[v2,2/3] kernel-shark-qt: Add I/O for configuration data.
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Message ID 20180814180348.17236-2-y.karadz@gmail.com
State New, archived
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Series
  • [v2,1/3] kernel-shark-qt: Add Json-C as a third party dependency.
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Commit Message

Yordan Karadzhov (VMware) Aug. 14, 2018, 6:03 p.m. UTC
Add to the C API of KernelShark instruments for importing/exporting
configuration settings to/from Json files. A wrapper is added in order
to abstract out completely the use of Json. This can be useful in the
future if we want to support multiple formats (YAML for example).

Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
---
 kernel-shark-qt/src/CMakeLists.txt       |    1 +
 kernel-shark-qt/src/libkshark-configio.c | 1276 ++++++++++++++++++++++
 kernel-shark-qt/src/libkshark.h          |  152 +++
 3 files changed, 1429 insertions(+)
 create mode 100644 kernel-shark-qt/src/libkshark-configio.c

Comments

Steven Rostedt Aug. 15, 2018, 2:46 a.m. UTC | #1
On Tue, 14 Aug 2018 21:03:47 +0300
"Yordan Karadzhov (VMware)" <y.karadz@gmail.com> wrote:

> Add to the C API of KernelShark instruments for importing/exporting
> configuration settings to/from Json files. A wrapper is added in order
> to abstract out completely the use of Json. This can be useful in the
> future if we want to support multiple formats (YAML for example).
> 
> Signed-off-by: Yordan Karadzhov (VMware) <y.karadz@gmail.com>
> ---
>  kernel-shark-qt/src/CMakeLists.txt       |    1 +
>  kernel-shark-qt/src/libkshark-configio.c | 1276 ++++++++++++++++++++++
>  kernel-shark-qt/src/libkshark.h          |  152 +++
>  3 files changed, 1429 insertions(+)
>  create mode 100644 kernel-shark-qt/src/libkshark-configio.c
> 
> diff --git a/kernel-shark-qt/src/CMakeLists.txt b/kernel-shark-qt/src/CMakeLists.txt
> index ea5dbda..a762da1 100644
> --- a/kernel-shark-qt/src/CMakeLists.txt
> +++ b/kernel-shark-qt/src/CMakeLists.txt
> @@ -3,6 +3,7 @@ message("\n src ...")
>  message(STATUS "libkshark")
>  add_library(kshark SHARED libkshark.c
>                            libkshark-model.c
> +                          libkshark-configio.c
>                            libkshark-collection.c)
>  
>  target_link_libraries(kshark ${CMAKE_DL_LIBS}
> diff --git a/kernel-shark-qt/src/libkshark-configio.c b/kernel-shark-qt/src/libkshark-configio.c
> new file mode 100644
> index 0000000..20f183f
> --- /dev/null
> +++ b/kernel-shark-qt/src/libkshark-configio.c
> @@ -0,0 +1,1276 @@
> +// SPDX-License-Identifier: LGPL-2.1
> +
> +/*
> + * Copyright (C) 2018 VMware Inc, Yordan Karadzhov <y.karadz@gmail.com>
> + */
> +
> + /**
> +  *  @file    libkshark-configio.c
> +  *  @brief   Json Configuration I/O.
> +  */
> +
> +// C
> +/** Use GNU C Library. */
> +#define _GNU_SOURCE
> +#include <stdio.h>
> +#include <sys/stat.h>
> +
> +// KernelShark
> +#include "libkshark.h"
> +#include "libkshark-model.h"
> +
> +/**
> + * @brief Create an empty Json document and set its type description.
> + *
> + * @param type: String describing the type of the document,
> + *		e.g. "kshark.record.config" or "kshark.filter.config".
> + *
> + * @returns json_object instance. Use json_object_put() to free the object.
> + */
> +struct json_object *kshark_json_config_alloc(const char *type)

Hmm, I thought you were going to make the json functons static?

Is this needed to be global?

> +{
> +	json_object *jobj, *jtype;
> +
> +	jobj = json_object_new_object();
> +	jtype = json_object_new_string(type);
> +
> +	if (!jobj || !jtype)
> +		goto fail;
> +
> +	/* Set the type of this Json document. */
> +	json_object_object_add(jobj, "type", jtype);
> +
> +	return jobj;
> +
> + fail:
> +	fprintf(stderr, "Failed to allocate memory for json_object.\n");
> +	json_object_put(jobj);
> +	json_object_put(jtype);
> +
> +	return NULL;
> +}
> +
> +/**
> + * @brief Allocate kshark_config_doc and set its format.
> + *
> + * @param format: Input location for the Configuration format identifier.
> + *		  Currently only Json and String formats are supported.
> + *
> + * @returns kshark_config_doc instance on success. Else NULL. Use
> + *	    free() to free the object.
> + */
> +struct kshark_config_doc *kshark_config_alloc(int format)

Have the format parameter be of type enum kshark_config_formats.

> +{
> +	struct kshark_config_doc *doc = NULL;
> +
> +	if (format == KS_JSON_CONFIG ||
> +	    format == KS_STRING_CONFIG) {
> +		doc = malloc(sizeof(*doc));
> +		doc->format = format;
> +		doc->conf_doc = NULL;
> +	}
> +
> +	return doc;
> +}
> +
> +/**
> + * @brief Create an empty Configuration document and set its format and type.
> + *
> + * @param type: String describing the type of the document,
> + *		e.g. "kshark.record.config" or "kshark.filter.config".
> + * @param format: Input location for the Configuration format identifier.
> + *		  Currently only Json format is supported.
> + *
> + * @returns kshark_config_doc instance on success. Else NULL. Use
> + *	    kshark_free_config_doc() to free the object.
> + */
> +struct kshark_config_doc *kshark_config_new(const char *type, int format)
> +{
> +	struct kshark_config_doc *doc = NULL;
> +
> +	if (format == KS_JSON_CONFIG) {
> +		doc = kshark_config_alloc(format);

Need to test if doc is NULL.

> +		doc->conf_doc = kshark_json_config_alloc(type);

And doc->conf_doc. If it is, then free doc and return NULL.

> +	}
> +
> +	return doc;
> +}
> +
> +/**
> + * @brief Free the Configuration document.
> + *
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json and String formats are supported. It is safe to pass
> + *		a NULL value.
> + */
> +void kshark_free_config_doc(struct kshark_config_doc *conf)
> +{
> +	if (!conf)
> +		return;
> +

Use a switch statement here:

	switch(conf->format) {
	case KS_JSON_CONFIG:

> +	if (conf->format == KS_JSON_CONFIG)
> +		json_object_put(conf->conf_doc);

		break;

	case KS_STRING_CONFIG:

Also, these should not be KS_*_CONFIG, but KS_CONFIG_*.

	KS_CONFIG_JSON
	KS_CONFIG_STRING

etc.

> +
> +	if (conf->format == KS_STRING_CONFIG)
> +		free(conf->conf_doc);
> +
> +	free(conf);
> +}
> +
> +/**
> + * @brief Use an existing Json document to create a new KernelShark
> + *	  Configuration document.
> + *
> + * @param jobj: Input location for the json_object instance.
> + *
> + * @returns shark_config_doc instance. Use kshark_free_config_doc() to free
> + *	    the object.
> + */
> +struct kshark_config_doc *kshark_json_to_conf(struct json_object *jobj)
> +{
> +	struct kshark_config_doc *conf = malloc(sizeof(*conf));
> +

Need to test if conf is NULL.

> +	conf->format = KS_JSON_CONFIG;
> +	conf->conf_doc = jobj;
> +
> +	return conf;
> +}
> +
> +/**
> + * @brief Use an existing string to create a new KernelShark Configuration
> + * document.
> + *
> + * @param val: Input location for the string.
> + *
> + * @returns kshark_config_doc instance. Use kshark_free_config_doc() to free
> + *	    the object.

		or NULL on error.

> + */
> +struct kshark_config_doc *kshark_string_to_conf(const char* val)
> +{
> +	struct kshark_config_doc *conf = malloc(sizeof(*conf));
> +	char *str;

Need to test if conf is NULL.

> +
> +	asprintf(&str, "%s", val);

Need to test the return value of asprintf().

> +	conf->conf_doc = str;
> +	conf->format = KS_STRING_CONFIG;
> +
> +	return conf;
> +}
> +
> +/**
> + * @brief Add a field to a KernelShark Configuration document.
> + *
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + * @param key: The name of the field.
> + * @param val: Input location for the kshark_config_doc to be added.
> + *	       Currently only Json and String formats are supported.
> + */
> +void kshark_config_doc_add(struct kshark_config_doc *conf,
> +			   const char *key,
> +			   struct kshark_config_doc *val)

Hmm, this seems a bit low level on the abstract area. I guess in need
to see the code that uses this (do you have a branch that converted to
this already?).

Ideally, we would want our kshark_config_doc to take something
directly, and not have it add another kshark_config_doc. That is, where
the creation of the val is, should probably be able to add to the conf
directly. Know what I mean?

> +{
> +	struct json_object *jobj;
> +
> +	if (!conf || !val)
> +		return;
> +
> +	if (val->format == KS_NOFORMAT_CONFIG)
> +		val->format = conf->format;
> +
> +	if (conf->format == KS_JSON_CONFIG) {
> +		if (val->format == KS_JSON_CONFIG) {
> +			json_object_object_add(conf->conf_doc, key,
> +					       val->conf_doc);
> +		}
> +
> +		if (val->format == KS_STRING_CONFIG) {
> +			jobj = json_object_new_string(val->conf_doc);
> +			json_object_object_add(conf->conf_doc, key, jobj);
> +		}
> +
> +		free(val);
> +	}
> +}
> +
> +static bool get_jval(struct kshark_config_doc *conf,
> +		     const char *key, void **val)
> +{
> +	return json_object_object_get_ex(conf->conf_doc, key,
> +					 (json_object **) val);
> +}
> +
> +/**
> + * @brief Get the KernelShark Configuration document associate with a given
> + *	  field name.
> + *
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + * @param key: The name of the field.
> + * @param val: Output location for the kshark_config_doc instance containing
> + *	       the field. Currently only Json and String formats are supported.
> + *
> + * @returns True, if the key exists. Else False.
> + */
> +bool kshark_config_doc_get(struct kshark_config_doc *conf,
> +			   const char *key,
> +			   struct kshark_config_doc *val)

I feel this is the same as add. Too low level. Again, I'll have to take
a look at how these are used in the finished product.

> +{
> +	if (!conf || !val)
> +		return false;
> +
> +	if (val->format == KS_NOFORMAT_CONFIG)
> +		val->format = conf->format;
> +
> +	if (conf->format == KS_JSON_CONFIG) {
> +		if (val->format == KS_JSON_CONFIG) {
> +			json_object_put(val->conf_doc);
> +			return get_jval(conf, key, &val->conf_doc);
> +		}
> +
> +		if (val->format == KS_STRING_CONFIG) {
> +			struct kshark_config_doc *tmp;
> +
> +			free(val->conf_doc);
> +
> +			tmp = kshark_config_alloc(KS_JSON_CONFIG);
> +			if (!get_jval(conf, key, &tmp->conf_doc))

Do we really want to return false after freeing an input parameter? If
anything, we should add:

			val->conf_doc = NULL;

right after it is freed.

> +				return false;
> +
> +			val->conf_doc =
> +				(char *) json_object_get_string(tmp->conf_doc);
> +			free(tmp);
> +
> +			return true;
> +		}
> +	}
> +
> +	return false;
> +}
> +
> +/**
> + * @brief Create an empty Record Configuration document. The type description
> + *	  is set to "kshark.record.config".
> + *
> + * @returns kshark_config_doc instance. Use kshark_free_config_doc() to free
> + *	    the object.
> + */
> +struct kshark_config_doc *kshark_record_config_new(int format)
> +{
> +	return kshark_config_new("kshark.record.config", format);
> +}
> +
> +/**
> + * @brief Create an empty Filter Configuration document. The type description
> + *	  is set to "kshark.filter.config".
> + *
> + * @returns kshark_config_doc instance. Use kshark_free_config_doc() to free
> + *	    the object.
> + */
> +struct kshark_config_doc *kshark_filter_config_new(int format)
> +{
> +	return kshark_config_new("kshark.filter.config", format);
> +}
> +
> +/**
> + * @brief Create an empty Data File Configuration document. The type
> + *	  description is set to "kshark.data.config".
> + *
> + * @returns kshark_config._doc instance. Use kshark_free_config_doc() to free
> + *	    the object
> + */
> +struct kshark_config_doc *kshark_data_config_alloc(int format)
> +{
> +	return kshark_config_new("kshark.data.config", format);
> +}
> +
> +/**
> + * @brief Create an empty Text Configuration document. The Text Configuration
> + *	  documents do not use type descriptions.
> + *
> + * @returns kshark_config_doc instance. Use free() to free the object.
> + */
> +struct kshark_config_doc *kshark_string_config_alloc()
> +{
> +	return kshark_config_alloc(KS_STRING_CONFIG);
> +}
> +
> +static void json_del_if_exist(struct json_object *jobj, const char *key)
> +{
> +	struct json_object *temp;
> +	if (json_object_object_get_ex(jobj, key, &temp))
> +	    json_object_object_del(jobj, key);
> +}
> +
> +static bool json_check_type(struct json_object *jobj, const char *type)
> +{
> +	struct json_object *jtype;
> +	const char *type_str;
> +
> +	if (!json_object_object_get_ex(jobj, "type", &jtype))
> +		return false;
> +
> +	type_str = json_object_get_string(jtype);
> +	if (strcmp(type_str, type) != 0)
> +		return false;
> +
> +	return true;
> +}
> +
> +static void kshark_trace_file_to_json(const char *file,

Should we have a state that gets returned to know if fails or not.

> +				      struct json_object *jobj)
> +{
> +	struct json_object *jdata, *jfile_name, *jtime;
> +	struct stat st;
> +
> +	if (!file || !jobj)
> +		return;
> +
> +	/*
> +	 * If this Json document already contains a descriprion of the data
> +	 * source, delete this descriprion.
> +	 */
> +	json_del_if_exist(jobj, KS_DATA_SOURCE_NAME);
> +
> +	if (stat(file, &st) != 0) {
> +		fprintf(stderr, "Unable to find file %s\n", file);
> +		return;
> +	}
> +
> +	jdata = kshark_json_config_alloc("kshark.data.config");
> +	jfile_name = json_object_new_string(file);
> +	jtime = json_object_new_int64(st.st_mtime);
> +
> +	if (!jdata || !jfile_name || !jtime)
> +		goto fail;
> +
> +	json_object_object_add(jdata, "file", jfile_name);
> +	json_object_object_add(jdata, "time", jtime);
> +
> +	json_object_object_add(jobj, KS_DATA_SOURCE_NAME, jdata);
> +
> +	return;
> +
> + fail:
> +	fprintf(stderr, "Failed to allocate memory for json_object.\n");
> +	json_object_put(jdata);
> +	json_object_put(jfile_name);
> +	json_object_put(jtime);
> +}
> +
> +/**
> + * @brief Record the name of a trace data file and its timestamp into a
> + *	  Configuration document.
> + *
> + * @param file: The name of the file.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + */
> +void kshark_export_trace_file(const char *file,
> +			      struct kshark_config_doc *conf)

Should have a return value to return state.

> +{
> +	if (conf->format == KS_JSON_CONFIG)
> +		kshark_trace_file_to_json(file, conf->conf_doc);

This could fail.

And if format is not JSON we should return failure for that too.

> +}
> +
> +static bool kshark_trace_file_from_json(const char **file,
> +					struct json_object *jobj)
> +{
> +	struct json_object *jdata, *jfile_name, *jtime;
> +	const char *file_str;
> +	struct stat st;
> +	int64_t time;
> +
> +	if (!jobj)
> +		return false;
> +
> +	if (!json_object_object_get_ex(jobj, KS_DATA_SOURCE_NAME, &jdata) ||
> +	    !json_check_type(jdata, "kshark.data.config") ||
> +	    !json_object_object_get_ex(jdata, "file", &jfile_name) ||
> +	    !json_object_object_get_ex(jdata, "time", &jtime)) {
> +		fprintf(stderr,
> +			"Failed to retrieve data file from json_object.\n");
> +		goto fail;
> +	}
> +
> +	file_str = json_object_get_string(jfile_name);

Can file_str be NULL?

> +	time = json_object_get_int64(jtime);
> +
> +	if (stat(file_str, &st) != 0) {
> +		fprintf(stderr, "Unable to find file %s\n", file_str);
> +		goto fail;
> +	}
> +
> +	if (st.st_mtime != time) {
> +		fprintf(stderr,"Timestamp mismatch!\nFile %s", file_str);
> +		fprintf(stderr," has been modified.\n");
> +		goto fail;
> +	}
> +
> +	*file = file_str;
> +	printf("file_from_json: %s\n", *file);
> +	return true;
> +
> + fail:
> +	json_object_put(jdata);
> +	json_object_put(jfile_name);
> +	json_object_put(jtime);
> +
> +	return false;
> +}
> +
> +/**
> + * @brief Read the name of a trace data file and its timestamp from a
> + *	  Configuration document and check if this file exists.
> + *
> + * @param file: Output location for the name of the file.

Hmm, file ends up pointing to the object that came from json. What
happens if that object is freed? This pointer may become corrupted,
right?

I don't like returning string pointers to objects that can be destroyed
internally.

Usually what I do is to malloc() the string, and document that it is up
to the caller to free it. Or have the string passed in along with a
length, and we fill the string.

> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + *
> + * @returns True, if the Configuration document contains a trace data file
> + *	    record and if such a file exists. Else False.
> + */
> +bool kshark_import_trace_file(const char **file,
> +			      struct kshark_config_doc *conf)
> +{
> +	if (conf->format == KS_JSON_CONFIG) {
> +		if (kshark_trace_file_from_json(file, conf->conf_doc))
> +			return true;
> +	}
> +
> +	return false;
> +}
> +
> +static void kshark_model_to_json(struct kshark_trace_histo *histo,
> +				 struct json_object *jobj)
> +{
> +	struct json_object *jmodel, *jrange, *jmin, *jmax, *jn_bins;
> +	if (!histo || !jobj)
> +		return;
> +
> +	/*
> +	 * If this Json document already contains a descriprion of the model,
> +	 * delete this descripron.

	"description"

> +	 */
> +	json_del_if_exist(jobj, KS_HISTO_NAME);
> +
> +	jmodel = kshark_json_config_alloc("kshark.model.config");
> +	jrange = json_object_new_array();
> +
> +	jmin = json_object_new_int64(histo->min);
> +	jmax = json_object_new_int64(histo->max);
> +	jn_bins = json_object_new_int(histo->n_bins);
> +
> +	if (!jmodel || !jrange || !jmin || !jmax || !jn_bins)
> +		goto fail;
> +
> +	json_object_array_put_idx(jrange, 0, jmin);
> +	json_object_array_put_idx(jrange, 1, jmax);
> +
> +	json_object_object_add(jmodel, "range", jrange);
> +	json_object_object_add(jmodel, "bins", jn_bins);
> +
> +	json_object_object_add(jobj, KS_HISTO_NAME, jmodel);
> +
> +	return;
> +
> + fail:
> +	fprintf(stderr, "Failed to allocate memory for json_object.\n");
> +	json_object_put(jmodel);
> +	json_object_put(jrange);
> +	json_object_put(jmin);
> +	json_object_put(jmax);
> +	json_object_put(jn_bins);
> +}
> +
> +/**
> + * @brief Record the current configuration of the Vis. model into a
> + *	  Configuration document.
> + * Load the configuration of the Vis. model from a Configuration
> + *	  document.
> + *
> + * @param histo: Input location for the Vis. model descriptor.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + */
> +void kshark_export_model(struct kshark_trace_histo *histo,
> +			 struct kshark_config_doc *conf)
> +{
> +	if (conf->format == KS_JSON_CONFIG)
> +		kshark_model_to_json(histo, conf->conf_doc);

We probably want to create a switch statement for all tests for
conf->format. The above could work like this:

	switch(conf->format) {
	case KS_JSON_CONFIG:
		kshark_model_to_json(histo, conf->conf_doc);
		break;
	default:
		fprintf(stderr, "Format %d not supported\n",
			conf->format);
	}


> +}
> +
> +static bool kshark_model_from_json(struct kshark_trace_histo *histo,
> +				   struct json_object *jobj)
> +{
> +	struct json_object *jmodel, *jrange, *jmin, *jmax, *jn_bins;
> +	uint64_t min, max;
> +	int n_bins;
> +
> +	if (!histo || !jobj)
> +		return false;
> +
> +	if (!json_object_object_get_ex(jobj, KS_HISTO_NAME, &jmodel))
> +		goto fail;
> +
> +	if (!json_check_type(jmodel, "kshark.model.config"))
> +		goto fail;
> +
> +	if (!json_object_object_get_ex(jmodel, "range", &jrange))
> +		goto fail;
> +
> +	if (json_object_get_type(jrange) != json_type_array)
> +		goto fail;
> +
> +	jmin = json_object_array_get_idx(jrange, 0);
> +	jmax = json_object_array_get_idx(jrange, 1);
> +	if (!jmin || !jmax)
> +		goto fail;
> +
> +	if (!json_object_object_get_ex(jmodel, "bins", &jn_bins))
> +		goto fail;
> +
> +	min = json_object_get_int64(jmin);
> +	max = json_object_get_int64(jmax);
> +	n_bins = json_object_get_int(jn_bins);
> +	ksmodel_set_bining(histo, n_bins, min, max);
> +
> +	if (histo->data && histo->data_size)
> +		ksmodel_fill(histo, histo->data, histo->data_size);
> +
> +	return true;
> +
> + fail:
> +	fprintf(stderr, "Failed to load event filter from json_object.\n");
> +	return false;
> +}
> +
> +/**
> + * @brief Load the configuration of the Vis. model from a Configuration
> + *	  document.
> + *
> + * @param histo: Input location for the Vis. model descriptor.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + */
> +void kshark_import_model(struct kshark_trace_histo *histo,
> +			 struct kshark_config_doc *conf)
> +{
> +	if (conf->format == KS_JSON_CONFIG)

Use switch statement here too.

> +		kshark_model_from_json(histo, conf->conf_doc);
> +}
> +
> +static void kshark_event_filter_to_json(struct pevent *pevent,
> +					struct tracecmd_filter_id *filter,
> +					const char *filter_name,
> +					struct json_object *jobj)
> +{
> +	json_object *jfilter_data, *jevent, *jsystem, *jname;
> +	int i, evt, *ids;
> +	char *temp;
> +
> +	/*
> +	 * If this Json document already contains a descriprion of the filter,
> +	 * delete this descriprion.
> +	 */
> +	json_del_if_exist(jobj, filter_name);
> +
> +
> +	/* Get the array of Ids to be fitered. */
> +	ids = tracecmd_filter_ids(filter);
> +	if (!ids)
> +		return;
> +
> +	/* Create a Json array and fill the Id values into it. */
> +	jfilter_data = json_object_new_array();
> +	if (!jfilter_data)
> +		goto fail;
> +
> +	for (i = 0; i < filter->count; ++i) {
> +		for (evt = 0; evt < pevent->nr_events; ++evt) {
> +			if (pevent->events[evt]->id == ids[i]) {
> +				jevent = json_object_new_object();
> +
> +				temp = pevent->events[evt]->system;
> +				jsystem = json_object_new_string(temp);
> +
> +				temp = pevent->events[evt]->name;
> +				jname = json_object_new_string(temp);
> +
> +				if (!jevent || !jsystem || !jname)
> +					goto fail;
> +
> +				json_object_object_add(jevent, "system",
> +							       jsystem);
> +
> +				json_object_object_add(jevent, "name",
> +							       jname);
> +
> +				json_object_array_add(jfilter_data, jevent);
> +
> +				break;
> +			}
> +		}
> +	}
> +
> +	free(ids);
> +
> +	/* Add the array of Ids to the filter config document. */
> +	json_object_object_add(jobj, filter_name, jfilter_data);
> +
> +	return;
> +
> + fail:
> +	fprintf(stderr, "Failed to allocate memory for json_object.\n");
> +	json_object_put(jfilter_data);
> +	json_object_put(jevent);
> +	json_object_put(jsystem);
> +	json_object_put(jname);
> +	free(ids);
> +}
> +
> +/**
> + * @brief Record the current configuration of an Event Id filter into a
> + *	  Configuration document.
> + *
> + * @param pevent: Input location for the Page event.
> + * @param filter: Input location for an Id filter.
> + * @param filter_name: The name of the filter to show up in the Json document.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + */
> +void kshark_export_event_filter(struct pevent *pevent,
> +				struct tracecmd_filter_id *filter,
> +				const char *filter_name,
> +				struct kshark_config_doc *conf)
> +{
> +	if (conf->format == KS_JSON_CONFIG)

switch statement here too.

> +		kshark_event_filter_to_json(pevent, filter, filter_name,
> +					    conf->conf_doc);
> +}
> +
> +static bool kshark_event_filter_from_json(struct pevent *pevent,
> +					  struct tracecmd_filter_id *filter,
> +					  const char *filter_name,
> +					  struct json_object *jobj)
> +{
> +	json_object *jfilter, *jevent, *jsystem, *jname;
> +	const char *system_str, *name_str;
> +	struct event_format *event;
> +	int i, length;
> +
> +	/*
> +	 * Use the name of the filter to find the array of events associated
> +	 * with this filter. Notice that the filter config document may
> +	 * contain no data for this particular filter.
> +	 */
> +	if (!json_object_object_get_ex(jobj, filter_name, &jfilter))
> +		return false;
> +
> +	if (!json_check_type(jobj, "kshark.filter.config") ||
> +	    json_object_get_type(jfilter) != json_type_array)
> +		goto fail;
> +
> +	/* Set the filter. */
> +	length = json_object_array_length(jfilter);
> +	for (i = 0; i < length; ++i) {
> +		jevent = json_object_array_get_idx(jfilter, i);
> +
> +		if (!json_object_object_get_ex(jevent, "system", &jsystem))
> +			goto fail;
> +
> +		if (!json_object_object_get_ex(jevent, "name", &jname))
> +			goto fail;
> +
> +		system_str = json_object_get_string(jsystem);
> +		name_str = json_object_get_string(jname);
> +
> +		event = pevent_find_event_by_name(pevent, system_str, name_str);
> +		if (!event)
> +			goto fail;
> +
> +		tracecmd_filter_id_add(filter, event->id);
> +	}
> +
> +	return true;
> +
> + fail:
> +	fprintf(stderr, "Failed to load event filter from json_object.\n");
> +	return false;
> +}
> +
> +/**
> + * @brief Load from Configuration document the configuration of an Event Id filter.
> + *
> + * @param pevent: Input location for the Page event.
> + * @param filter: Input location for an Id filter.
> + * @param filter_name: The name of the filter as showing up in the Config.
> + *	               document.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + *
> + * @returns True, if a filter has been loaded. If the filter configuration
> + *	    document contains no data for this particular filter or in a case
> + *	    of an error, the function returns False.
> + */
> +bool kshark_import_event_filter(struct pevent *pevent,
> +				struct tracecmd_filter_id *filter,
> +				const char *filter_name,
> +				struct kshark_config_doc *conf)
> +{
> +	if (conf->format == KS_JSON_CONFIG)

switch here too.

> +		return kshark_event_filter_from_json(pevent, filter,
> +						     filter_name,
> +						     conf->conf_doc);
> +
> +	return false;
> +}
> +
> +static void kshark_task_filter_to_json(struct tracecmd_filter_id *filter,
> +				       const char *filter_name,
> +				       struct json_object *jobj)
> +{
> +	json_object *jfilter_data, *jpid;
> +	int i, *ids;
> +
> +	/*
> +	 * If this Json document already contains a descriprion of the model,
> +	 * delete this descriprion.
> +	 */
> +	json_del_if_exist(jobj, filter_name);
> +
> +	/* Get the array of Ids to be fitered. */
> +	ids = tracecmd_filter_ids(filter);
> +	if (!ids)
> +		return;
> +
> +	/* Create a Json array and fill the Id values into it. */
> +	jfilter_data = json_object_new_array();
> +	if (!jfilter_data)
> +		goto fail;
> +
> +	for (i = 0; i < filter->count; ++i) {
> +		jpid = json_object_new_int(ids[i]);
> +		if (!jpid)
> +			goto fail;
> +
> +		json_object_array_add(jfilter_data, jpid);
> +	}
> +
> +	free(ids);
> +
> +	/* Add the array of Ids to the filter config document. */
> +	json_object_object_add(jobj, filter_name, jfilter_data);
> +
> +	return;
> +
> + fail:
> +	fprintf(stderr, "Failed to allocate memory for json_object.\n");
> +	json_object_put(jfilter_data);
> +	json_object_put(jpid);
> +	free(ids);
> +}
> +
> +/**
> + * @brief Record the current configuration of a Task Id filter into a
> + *	  Configuration document.
> + *
> + * @param filter: Input location for an Id filter.
> + * @param filter_name: The name of the filter to show up in the Json document.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + */
> +void kshark_export_task_filter(struct tracecmd_filter_id *filter,
> +			       const char *filter_name,
> +			       struct kshark_config_doc *conf)
> +{
> +	if (conf->format == KS_JSON_CONFIG)

switch here too.

> +		kshark_task_filter_to_json(filter, filter_name,
> +					   conf->conf_doc);
> +}
> +
> +static bool kshark_task_filter_from_json(struct tracecmd_filter_id *filter,
> +					 const char *filter_name,
> +					 struct json_object *jobj)
> +{
> +	json_object *jfilter, *jpid;
> +	int i, length;
> +
> +	/*
> +	 * Use the name of the filter to find the array of events associated
> +	 * with this filter. Notice that the filter config document may
> +	 * contain no data for this particular filter.
> +	 */
> +	if (!json_object_object_get_ex(jobj, filter_name, &jfilter))
> +		return false;
> +
> +	if (!json_check_type(jobj, "kshark.filter.config") ||
> +	    json_object_get_type(jfilter) != json_type_array)
> +		goto fail;
> +
> +	/* Set the filter. */
> +	length = json_object_array_length(jfilter);
> +	for (i = 0; i < length; ++i) {
> +		jpid = json_object_array_get_idx(jfilter, i);
> +		if (!jpid)
> +			goto fail;
> +
> +		tracecmd_filter_id_add(filter, json_object_get_int(jpid));
> +	}
> +
> +	return true;
> +
> + fail:
> +	fprintf(stderr, "Failed to load task filter from json_object.\n");
> +	return false;
> +}
> +
> +/**
> + * @brief Load from Configuration document the configuration of a Task Id filter.
> + *
> + * @param filter: Input location for an Id filter.
> + * @param filter_name: The name of the filter as showing up in the Config.
> + *	               document.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + *
> + * @returns True, if a filter has been loaded. If the filter configuration
> + *	    document contains no data for this particular filter or in a case
> + *	    of an error, the function returns False.
> + */
> +bool kshark_import_task_filter(struct tracecmd_filter_id *filter,
> +			       const char *filter_name,
> +			       struct kshark_config_doc *conf)
> +{
> +	if (conf->format == KS_JSON_CONFIG)

switch here too.

> +		return kshark_task_filter_from_json(filter, filter_name,
> +						    conf->conf_doc);
> +
> +	return false;
> +}
> +
> +static void kshark_adv_filters_to_json(struct kshark_context *kshark_ctx,
> +				       struct json_object *jobj)
> +{
> +	struct event_filter *adv_filter = kshark_ctx->advanced_event_filter;
> +	json_object *jfilter_data, *jevent, *jsystem, *jname, *jfilter;
> +	struct event_format **events;
> +	char *str;
> +	int i;
> +
> +	/*
> +	 * If this Json document already contains a descriprion of the model,
> +	 * delete this descriprion.
> +	 */
> +	json_del_if_exist(jobj, KS_ADV_EVENT_FILTER_NAME);
> +
> +	if (!kshark_ctx->advanced_event_filter ||
> +	    !kshark_ctx->advanced_event_filter->filters)
> +		return;
> +
> +	/* Create a Json array and fill the Id values into it. */
> +	jfilter_data = json_object_new_array();
> +	if (!jfilter_data)
> +		goto fail;
> +
> +	events = pevent_list_events(kshark_ctx->pevent, EVENT_SORT_SYSTEM);
> +	if (!events)
> +		return;
> +
> +	for (i = 0; events[i]; i++) {
> +		str = pevent_filter_make_string(adv_filter,
> +						events[i]->id);
> +		if (!str)
> +			continue;
> +
> +		jevent = json_object_new_object();
> +		jsystem = json_object_new_string(events[i]->system);
> +		jname = json_object_new_string(events[i]->name);
> +		jfilter = json_object_new_string(str);
> +		if (!jevent || !jsystem || !jname || !jfilter)
> +			goto fail;
> +
> +		json_object_object_add(jevent, "system", jsystem);
> +		json_object_object_add(jevent, "name", jname);
> +		json_object_object_add(jevent, "condition", jfilter);
> +
> +		json_object_array_add(jfilter_data, jevent);
> +	}
> +
> +	/* Add the array of advanced filters to the filter config document. */
> +	json_object_object_add(jobj, KS_ADV_EVENT_FILTER_NAME, jfilter_data);
> +
> +	return;
> +
> + fail:
> +	fprintf(stderr, "Failed to allocate memory for json_object.\n");
> +	json_object_put(jfilter_data);
> +	json_object_put(jevent);
> +	json_object_put(jsystem);
> +	json_object_put(jname);
> +	json_object_put(jfilter);
> +}
> +
> +/**
> + * @brief Record the current configuration of the advanced filter into a
> + *	  Configuration document.
> + *
> + * @param kshark_ctx: Input location for session context pointer.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported. If NULL, a new Adv. Filter
> + *		Configuration document will be created.

We should have a format parameter here, where they can specify what
type to create (currently only KS_JSON_CONFIG is supported). Otherwise,
how would one pass something else in when if we support something else?

> + */
> +void kshark_export_adv_filters(struct kshark_context *kshark_ctx,
> +			       struct kshark_config_doc **conf)
> +{
> +	if (!*conf)
> +		*conf = kshark_filter_config_new(KS_JSON_CONFIG);
> +
> +	if ((*conf)->format == KS_JSON_CONFIG)
> +		kshark_adv_filters_to_json(kshark_ctx, (*conf)->conf_doc);
> +}
> +
> +static bool kshark_adv_filters_from_json(struct kshark_context *kshark_ctx,
> +					 struct json_object *jobj)
> +{
> +	struct event_filter *adv_filter = kshark_ctx->advanced_event_filter;
> +	json_object *jfilter, *jsystem, *jname, *jcond;
> +	int i, length, ret;
> +	char *filter_str;
> +
> +	/*
> +	 * Use the name of the filter to find the array of events associated
> +	 * with this filter. Notice that the filter config document may
> +	 * contain no data for this particular filter.
> +	 */
> +	if (!json_object_object_get_ex(jobj, KS_ADV_EVENT_FILTER_NAME,
> +				       &jfilter))
> +		return false;
> +
> +	if (!json_check_type(jobj, "kshark.filter.config") ||
> +	    json_object_get_type(jfilter) != json_type_array)
> +		goto fail;
> +
> +	/* Set the filter. */
> +	length = json_object_array_length(jfilter);
> +	for (i = 0; i < length; ++i) {
> +		jfilter = json_object_array_get_idx(jfilter, i);
> +
> +		if (!json_object_object_get_ex(jfilter, "system", &jsystem))
> +			goto fail;
> +
> +		if (!json_object_object_get_ex(jfilter, "name", &jname))
> +			goto fail;
> +
> +		if (!json_object_object_get_ex(jfilter, "condition", &jcond))
> +			goto fail;
> +
> +		asprintf(&filter_str, "%s/%s:%s",
> +			 json_object_get_string(jsystem),
> +			 json_object_get_string(jname),
> +			 json_object_get_string(jcond));
> +
> +		ret = pevent_filter_add_filter_str(adv_filter,
> +						   filter_str);
> +		if (ret < 0)
> +			goto fail;
> +	}
> +
> +	return true;
> +
> + fail:
> +	fprintf(stderr, "Failed to laod Advanced filters.\n");
> +	char error_str[200];
> +	int error_status =
> +		pevent_strerror(kshark_ctx->pevent, ret, error_str,
> +							 sizeof(error_str));
> +
> +	if (error_status == 0)
> +		fprintf(stderr, "filter failed due to: %s\n", error_str);
> +
> +	free(filter_str);
> +	return false;
> +}
> +
> +/**
> + * @brief Load from Configuration document the configuration of the advanced
> + *	  filter.
> + *
> + * @param kshark_ctx: Input location for session context pointer.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.

I don't think you need to document that only Json format is supported
at every function. Just the ones that create it. Other than that,
these functions shouldn't care about what is supported behind the
scenes. If someone was able to create a kshark_config_doc, then they
should be able to use it.


> + *
> + * @returns True, if a filter has been loaded. If the filter configuration
> + *	    document contains no data for this particular filter or in a case
> + *	    of an error, the function returns False.
> + */
> +bool kshark_import_adv_filters(struct kshark_context *kshark_ctx,
> +			       struct kshark_config_doc *conf)
> +{
> +	if (conf->format == KS_JSON_CONFIG)
> +		return kshark_adv_filters_from_json(kshark_ctx,
> +						    conf->conf_doc);
> +
> +	return false;
> +}
> +
> +static bool filter_is_set(struct tracecmd_filter_id *filter)
> +{
> +	return filter && filter->count;
> +}
> +
> +/**
> + * @brief Record the current configuration of "show task" and "hide task"
> + *	  filters into a Json document.
> + *
> + * @param kshark_ctx: Input location for session context pointer.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported. If NULL, a new Filter
> + *		Configuration document will be created.
> + */
> +void kshark_export_all_event_filters(struct kshark_context *kshark_ctx,
> +				     struct kshark_config_doc **conf)
> +{
> +	if (!*conf)
> +		*conf = kshark_filter_config_new(KS_JSON_CONFIG);
> +
> +	/* Save a filter only if it contains Id values. */
> +	if (filter_is_set(kshark_ctx->show_event_filter))
> +		kshark_export_event_filter(kshark_ctx->pevent,
> +					   kshark_ctx->show_event_filter,
> +					   KS_SHOW_EVENT_FILTER_NAME,
> +					   *conf);
> +
> +	if (filter_is_set(kshark_ctx->hide_event_filter))
> +		kshark_export_event_filter(kshark_ctx->pevent,
> +					   kshark_ctx->hide_event_filter,
> +					   KS_HIDE_EVENT_FILTER_NAME,
> +					   *conf);
> +}
> +
> +/**
> + * @brief Record the current configuration of "show task" and "hide task"
> + *	  filters into a Configuration document.
> + *
> + * @param kshark_ctx: Input location for session context pointer.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported. If NULL, a new Filter
> + *		Configuration document will be created.

Again, we should allow a format parameter to let the user decide what
type of format to use. Currently only Json.

Allow a zero or KS_

> + */
> +void kshark_export_all_task_filters(struct kshark_context *kshark_ctx,
> +				    struct kshark_config_doc **conf)
> +{
> +	if (!*conf)
> +		*conf = kshark_filter_config_new(KS_JSON_CONFIG);
> +
> +	/* Save a filter only if it contains Id values. */
> +	if (filter_is_set(kshark_ctx->show_task_filter))
> +		kshark_export_task_filter(kshark_ctx->show_task_filter,
> +					  KS_SHOW_TASK_FILTER_NAME,
> +					  *conf);
> +
> +	if (filter_is_set(kshark_ctx->hide_task_filter))
> +		kshark_export_task_filter(kshark_ctx->hide_task_filter,
> +					  KS_HIDE_TASK_FILTER_NAME,
> +					  *conf);
> +}
> +
> +/**
> + * @brief Load from a Configuration document the configuration of "show event"
> + *	  and "hide event" filters.
> + *
> + * @param kshark_ctx: Input location for session context pointer.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + *
> + * @returns True, if a filter has been loaded. If the filter configuration
> + *	    document contains no data for any event filter or in a case
> + *	    of an error, the function returns False.
> + */
> +bool kshark_import_all_event_filters(struct kshark_context *kshark_ctx,
> +				     struct kshark_config_doc *conf)
> +{
> +	bool status;
> +
> +	status = kshark_import_event_filter(kshark_ctx->pevent,
> +					    kshark_ctx->hide_event_filter,
> +					    KS_HIDE_EVENT_FILTER_NAME,
> +					    conf);
> +
> +	status |= kshark_import_event_filter(kshark_ctx->pevent,
> +					     kshark_ctx->show_event_filter,
> +					     KS_SHOW_EVENT_FILTER_NAME,
> +					     conf);
> +
> +	return status;
> +}
> +
> +/**
> + * @brief Load from Configuration document the configuration of "show task"
> + *	  and "hide task" filters.
> + *
> + * @param kshark_ctx: Input location for session context pointer.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + *
> + * @returns True, if a filter has been loaded. If the filter configuration
> + *	    document contains no data for any task filter or in a case of an
> + *	    error, the function returns False.
> + */
> +bool kshark_import_all_task_filters(struct kshark_context *kshark_ctx,
> +				    struct kshark_config_doc *conf)
> +{
> +	bool status;
> +
> +	status = kshark_import_task_filter(kshark_ctx->hide_task_filter,
> +					   KS_HIDE_TASK_FILTER_NAME,
> +					   conf);
> +
> +	status |= kshark_import_task_filter(kshark_ctx->show_task_filter,
> +					    KS_SHOW_TASK_FILTER_NAME,
> +					    conf);
> +
> +	return status;
> +}
> +
> +/**
> + * @brief Create a Filter Configuration document containing the current
> + *	  configuration of all filters.
> + *
> + * @param kshark_ctx: Input location for session context pointer.

Here we should also pass in a format to choose JSON, to allow other
formats to be exported later.


> + *
> + * @returns kshark_config_doc instance. Use kshark_free_config_doc() to free
> + *	    the object.
> + */
> +struct kshark_config_doc *
> +kshark_export_all_filters(struct kshark_context *kshark_ctx)
> +{
> +	/*  Create a new Configuration document. */
> +	struct kshark_config_doc *conf =
> +		kshark_filter_config_new(KS_JSON_CONFIG);
> +
> +	/* Save a filter only if it contains Id values. */
> +	kshark_export_all_event_filters(kshark_ctx, &conf);
> +	kshark_export_all_task_filters(kshark_ctx, &conf);
> +	kshark_export_adv_filters(kshark_ctx, &conf);
> +
> +	return conf;
> +}
> +
> +/**
> + * @brief Load from a Configuration document the configuration of all filters.
> + *
> + * @param kshark_ctx: Input location for session context pointer.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + *
> + * @returns True, if a filter has been loaded. If the filter configuration
> + *	    document contains no data for any filter or in a case of an error,
> + *	    the function returns False.
> + */
> +bool kshark_import_all_filters(struct kshark_context *kshark_ctx,
> +			       struct kshark_config_doc *conf)
> +{
> +	bool status;
> +	status = kshark_import_all_task_filters(kshark_ctx, conf);
> +	status |= kshark_import_all_event_filters(kshark_ctx, conf);
> +	status |= kshark_import_adv_filters(kshark_ctx, conf);
> +
> +	return status;
> +}
> +
> +static void kshark_save_json_file(const char *file_name,
> +				  struct json_object *jobj)
> +{
> +	int flags;
> +
> +	/* Save the file in a human-readable form. */
> +	flags = JSON_C_TO_STRING_SPACED | JSON_C_TO_STRING_PRETTY;
> +	json_object_to_file_ext(file_name, jobj, flags);
> +}
> +
> +/**
> + * @brief Save a Configuration document into a file.
> + *
> + * @param file_name: The name of the file.
> + * @param conf: Input location for the kshark_config_doc instance. Currently
> + *		only Json format is supported.
> + */
> +void kshark_save_config_file(const char *file_name,
> +			     struct kshark_config_doc *conf)
> +{
> +	if (conf->format == KS_JSON_CONFIG)
> +		kshark_save_json_file(file_name, conf->conf_doc);
> +}
> +
> +static struct json_object *kshark_open_json_file(const char *file_name,
> +						 const char *type)
> +{
> +	struct json_object *jobj, *var;
> +	const char *type_var;
> +
> +	jobj = json_object_from_file(file_name);
> +
> +	if (!jobj)
> +		return NULL;
> +
> +	/* Get the type of the document. */
> +	if (!json_object_object_get_ex(jobj, "type", &var))
> +		goto fail;
> +
> +	type_var = json_object_get_string(var);
> +
> +	if (strcmp(type, type_var) != 0)
> +		goto fail;
> +
> +	return jobj;
> +
> + fail:
> +	/* The document has a wrong type. */
> +	fprintf(stderr, "Failed to open Json file %s\n.", file_name);
> +	fprintf(stderr, "The document has a wrong type.\n");
> +
> +	json_object_put(jobj);
> +	return NULL;
> +}
> +
> +static const char *get_ext(const char *filename)
> +{
> +	const char *dot = strrchr(filename, '.');
> +
> +	if(!dot)
> +		return "unknown";
> +
> +	return dot + 1;
> +}
> +
> +/**
> + * @brief Open a for read a Configuration file and check if it has the
> + *	  expected type.
> + *
> + * @param file_name: The name of the file. Currently only Json files are
> + *		     supported.
> + * @param type: String describing the expected type of the document,
> + *		e.g. "kshark.record.config" or "kshark.filter.config".
> + *
> + * @returns kshark_config_doc instance on success, or NULL on failure. Use
> + *	    kshark_free_config_doc() to free the object.
> + */
> +struct kshark_config_doc *kshark_open_config_file(const char *file_name,
> +						  const char *type)
> +{
> +	struct kshark_config_doc *conf = NULL;
> +
> +	if (strcmp(get_ext(file_name), "json") == 0) {
> +		struct json_object *jobj =
> +			kshark_open_json_file(file_name, type);
> +
> +		if (jobj) {
> +			conf = malloc(sizeof(*conf));
> +			conf->conf_doc = jobj;
> +			conf->format = KS_JSON_CONFIG;
> +		}
> +	}
> +
> +	return conf;
> +}
> diff --git a/kernel-shark-qt/src/libkshark.h b/kernel-shark-qt/src/libkshark.h
> index ff09da3..4fe4420 100644
> --- a/kernel-shark-qt/src/libkshark.h
> +++ b/kernel-shark-qt/src/libkshark.h
> @@ -16,6 +16,9 @@
>  #include <stdint.h>
>  #include <pthread.h>
>  
> +// Json-C
> +#include <json.h>
> +
>  #ifdef __cplusplus
>  extern "C" {
>  #endif
> @@ -367,6 +370,155 @@ kshark_get_collection_entry_back(struct kshark_entry_request **req,
>  				 const struct kshark_entry_collection *col,
>  				 ssize_t *index);
>  
> +/** Structure representing a KernelShark Configuration document. */
> +struct kshark_config_doc {
> +	/** Document format identifier. */
> +	int	format;
> +
> +	/** Configuration document instance. */
> +	void	*conf_doc;
> +};
> +
> +/** Configuration format identifiers. */
> +enum kshark_config_formats {
> +	/** Unformatted Configuration document identifier. */
> +	KS_NOFORMAT_CONFIG = 0,

Perhaps we should rename this to

	KS_CONFIG_DEFAULT = 0,

so that it can be passed above as the format parameter to allow the
application to use the default format, if the developer doesn't care
what it uses. It would also be the option to use if a conf is defined,
where we could create one if it wasn't.

> +
> +	/**
> +	 * String Configuration document identifier. The String format is
> +	 * meant to be used only by kshark_config_doc_add() and
> +	 * kshark_config_doc_get(), when adding/getting simple string fields.
> +	 */
> +	KS_STRING_CONFIG,

Rename to:

	KS_CONFIG_STRING

> +
> +	/** Json Configuration document identifier. */
> +	KS_JSON_CONFIG,

Rename to:

	KS_CONFIG_JSON

This way it's easier to define and see what they are.

Note, I looked at this pretty late at night, so I may not be making
much sense above. But hopefully you understood at least 50% of what I
said ;-)


-- Steve


> +};
> +
> +/**
> + * Field name for the Configuration document describing the Hide Event filter.
> + */
> +#define KS_HIDE_EVENT_FILTER_NAME	"hide event filter"
> +
> +/**
> + * Field name for the Configuration document describing the Show Event filter.
> + */
> +#define KS_SHOW_EVENT_FILTER_NAME	"show event filter"
> +
> +/**
> + * Field name for the Configuration document describing the Hide Task filter.
> + */
> +#define KS_HIDE_TASK_FILTER_NAME	"hide task filter"
> +
> +/**
> + * Field name for the Configuration document describing the Show Task filter.
> + */
> +#define KS_SHOW_TASK_FILTER_NAME	"show task filter"
> +
> +/**
> + * Field name for the Configuration document describing the Advanced event
> + * filter.
> + */
> +#define KS_ADV_EVENT_FILTER_NAME	"adv event filter"
> +
> +/**
> + * Field name for the Configuration document describing the state of the Vis.
> + * model.
> + */
> +#define KS_HISTO_NAME			"vis. model"
> +
> +/**
> + * Field name for the Configuration document describing the currently loaded
> + * trace data file.
> + */
> +#define KS_DATA_SOURCE_NAME		"trace data"
> +
> +struct json_object *kshark_json_config_alloc(const char *type);
> +
> +struct kshark_config_doc *kshark_config_alloc(int format);
> +
> +struct kshark_config_doc *kshark_config_new(const char *type, int format);
> +
> +void kshark_free_config_doc(struct kshark_config_doc *conf);
> +
> +struct kshark_config_doc *kshark_record_config_new(int format);
> +
> +struct kshark_config_doc *kshark_filter_config_new(int format);
> +
> +struct kshark_config_doc *kshark_string_config_alloc();
> +
> +void kshark_config_doc_add(struct kshark_config_doc *conf,
> +			   const char *key,
> +			   struct kshark_config_doc *val);
> +
> +bool kshark_config_doc_get(struct kshark_config_doc *conf,
> +			   const char *key,
> +			   struct kshark_config_doc *val);
> +
> +struct kshark_trace_histo;
> +
> +void kshark_export_trace_file(const char *file,
> +			      struct kshark_config_doc *conf);
> +
> +bool kshark_import_trace_file(const char **file,
> +			      struct kshark_config_doc *conf);
> +
> +void kshark_export_model(struct kshark_trace_histo *histo,
> +			 struct kshark_config_doc *conf);
> +
> +void kshark_import_model(struct kshark_trace_histo *histo,
> +			 struct kshark_config_doc *conf);
> +
> +void kshark_export_adv_filters(struct kshark_context *kshark_ctx,
> +			       struct kshark_config_doc **conf);
> +
> +bool kshark_import_adv_filters(struct kshark_context *kshark_ctx,
> +			       struct kshark_config_doc *conf);
> +
> +void kshark_export_event_filter(struct pevent *pevent,
> +				struct tracecmd_filter_id *filter,
> +				const char *filter_name,
> +				struct kshark_config_doc *conf);
> +
> +bool kshark_import_event_filter(struct pevent *pevent,
> +				struct tracecmd_filter_id *filter,
> +				const char *filter_name,
> +				struct kshark_config_doc *conf);
> +
> +void kshark_export_task_filter(struct tracecmd_filter_id *filter,
> +			       const char *filter_name,
> +			       struct kshark_config_doc *conf);
> +
> +bool kshark_import_task_filter(struct tracecmd_filter_id *filter,
> +			       const char *filter_name,
> +			       struct kshark_config_doc *conf);
> +
> +void kshark_export_all_event_filters(struct kshark_context *kshark_ctx,
> +				     struct kshark_config_doc **conf);
> +
> +void kshark_export_all_task_filters(struct kshark_context *kshark_ctx,
> +				    struct kshark_config_doc **conf);
> +
> +struct kshark_config_doc *
> +kshark_export_all_filters(struct kshark_context *kshark_ctx);
> +
> +bool kshark_import_all_event_filters(struct kshark_context *kshark_ctx,
> +				     struct kshark_config_doc *conf);
> +
> +bool kshark_import_all_task_filters(struct kshark_context *kshark_ctx,
> +				    struct kshark_config_doc *conf);
> +
> +bool kshark_import_all_filters(struct kshark_context *kshark_ctx,
> +			       struct kshark_config_doc *conf);
> +
> +void kshark_save_config_file(const char *file_name,
> +			     struct kshark_config_doc *conf);
> +
> +struct kshark_config_doc *kshark_open_config_file(const char *file_name,
> +						  const char *type);
> +
> +struct kshark_config_doc *kshark_json_to_conf(struct json_object *jobj);
> +
>  #ifdef __cplusplus
>  }
>  #endif
Yordan Karadzhov (VMware) Aug. 15, 2018, 2:11 p.m. UTC | #2
Hi Steven,

On 15.08.2018 05:46, Steven Rostedt wrote:
>> +
>> +/**
>> + * @brief Add a field to a KernelShark Configuration document.
>> + *
>> + * @param conf: Input location for the kshark_config_doc instance. Currently
>> + *		only Json format is supported.
>> + * @param key: The name of the field.
>> + * @param val: Input location for the kshark_config_doc to be added.
>> + *	       Currently only Json and String formats are supported.
>> + */
>> +void kshark_config_doc_add(struct kshark_config_doc *conf,
>> +			   const char *key,
>> +			   struct kshark_config_doc *val)
> Hmm, this seems a bit low level on the abstract area. I guess in need
> to see the code that uses this (do you have a branch that converted to
> this already?).
> 
> Ideally, we would want our kshark_config_doc to take something
> directly, and not have it add another kshark_config_doc. That is, where
> the creation of the val is, should probably be able to add to the conf
> directly. Know what I mean?
> 

I would prefer to keep the *doc_add and *doc_get functions. I need ADD 
and GET because of the way the information gets structured in the 
configuration document. See an example of a Session description file below:

{
    "type": "kshark.session.config",
    "MainWindow": [
      898,
      538
    ],
    "Markers": {
      "type": "kshark.markers.config",
      "markA": {
        "isSet": false
      },
      "markB": {
        "isSet": false
      },
      "Active": "A"
    },
    "Filters": {
      "type": "kshark.filter.config",
      "show task filter": [
        314,
        42
      ]
    },
    "ViewTop": 16988720,
    "ColorScheme": 0.75,
    "trace data": {
      "type": "kshark.data.config",
      "file": 
"\/home\/yordan\/Workspace\/trace-cmd_qtdev\/kernel-shark-qt\/bin\/trace_very_big.dat",
      "time": 1520425749
    },
    "vis. model": {
      "type": "kshark.model.config",
      "range": [
        119984624152884,
        119984638388301
      ],
      "bins": 777
    },
    "CpuPlots": [
      0,
      1,
      2,
      3,
      4,
      5,
      6,
      7
    ],
    "TaskPlots": [
    ]
  }

In this example we have the top level document having
  "type": "kshark.session.config"

This top level document contains some simple field like:
"MainWindow", "ViewTop", "ColorScheme" etc.

but it also contains other documents, having there own types.
Like "Markers", "Filters", "vis. model" etc.

If the user only wants to export the filtering settings the 
"kshark.filter.config" documents is enough.
However when we want to save the entire session, we first create
"kshark.filter.config" and then we ADD this document to 
kshark.session.config

I've tried to demonstrate the way all this works in the example added in 
the following patch.

What do you think?

Thanks!
Yordan


>> +{
>> +	struct json_object *jobj;
>> +
>> +	if (!conf || !val)
>> +		return;
>> +
>> +	if (val->format == KS_NOFORMAT_CONFIG)
>> +		val->format = conf->format;
>> +
>> +	if (conf->format == KS_JSON_CONFIG) {
>> +		if (val->format == KS_JSON_CONFIG) {
>> +			json_object_object_add(conf->conf_doc, key,
>> +					       val->conf_doc);
>> +		}
>> +
>> +		if (val->format == KS_STRING_CONFIG) {
>> +			jobj = json_object_new_string(val->conf_doc);
>> +			json_object_object_add(conf->conf_doc, key, jobj);
>> +		}
>> +
>> +		free(val);
>> +	}
>> +}
>> +
>> +static bool get_jval(struct kshark_config_doc *conf,
>> +		     const char *key, void **val)
>> +{
>> +	return json_object_object_get_ex(conf->conf_doc, key,
>> +					 (json_object **) val);
>> +}
>> +
>> +/**
>> + * @brief Get the KernelShark Configuration document associate with a given
>> + *	  field name.
>> + *
>> + * @param conf: Input location for the kshark_config_doc instance. Currently
>> + *		only Json format is supported.
>> + * @param key: The name of the field.
>> + * @param val: Output location for the kshark_config_doc instance containing
>> + *	       the field. Currently only Json and String formats are supported.
>> + *
>> + * @returns True, if the key exists. Else False.
>> + */
>> +bool kshark_config_doc_get(struct kshark_config_doc *conf,
>> +			   const char *key,
>> +			   struct kshark_config_doc *val)
> I feel this is the same as add. Too low level. Again, I'll have to take
> a look at how these are used in the finished product.
>
Yordan Karadzhov (VMware) Aug. 15, 2018, 2:16 p.m. UTC | #3
Hi Steven,

On 15.08.2018 05:46, Steven Rostedt wrote:
>> +/**
>> + * @brief Record the current configuration of the advanced filter into a
>> + *	  Configuration document.
>> + *
>> + * @param kshark_ctx: Input location for session context pointer.
>> + * @param conf: Input location for the kshark_config_doc instance. Currently
>> + *		only Json format is supported. If NULL, a new Adv. Filter
>> + *		Configuration document will be created.
> We should have a format parameter here, where they can specify what
> type to create (currently only KS_JSON_CONFIG is supported). Otherwise,
> how would one pass something else in when if we support something else?
> 

The idea here is that the user is expected to provide an instance of 
kshark_config_doc and this instance already has a format.

A new instance will be created only in the case of passing conf = NULL.
In this case the new instance will have the default format (Json).

I agree that it looks peculiar, because we support only one format for 
the moment. ;-)

Thanks!
Yordan


>> + */
>> +void kshark_export_adv_filters(struct kshark_context *kshark_ctx,
>> +			       struct kshark_config_doc **conf)
>> +{
>> +	if (!*conf)
>> +		*conf = kshark_filter_config_new(KS_JSON_CONFIG);
>> +
>> +	if ((*conf)->format == KS_JSON_CONFIG)
>> +		kshark_adv_filters_to_json(kshark_ctx, (*conf)->conf_doc);
>> +}

Patch
diff mbox series

diff --git a/kernel-shark-qt/src/CMakeLists.txt b/kernel-shark-qt/src/CMakeLists.txt
index ea5dbda..a762da1 100644
--- a/kernel-shark-qt/src/CMakeLists.txt
+++ b/kernel-shark-qt/src/CMakeLists.txt
@@ -3,6 +3,7 @@  message("\n src ...")
 message(STATUS "libkshark")
 add_library(kshark SHARED libkshark.c
                           libkshark-model.c
+                          libkshark-configio.c
                           libkshark-collection.c)
 
 target_link_libraries(kshark ${CMAKE_DL_LIBS}
diff --git a/kernel-shark-qt/src/libkshark-configio.c b/kernel-shark-qt/src/libkshark-configio.c
new file mode 100644
index 0000000..20f183f
--- /dev/null
+++ b/kernel-shark-qt/src/libkshark-configio.c
@@ -0,0 +1,1276 @@ 
+// SPDX-License-Identifier: LGPL-2.1
+
+/*
+ * Copyright (C) 2018 VMware Inc, Yordan Karadzhov <y.karadz@gmail.com>
+ */
+
+ /**
+  *  @file    libkshark-configio.c
+  *  @brief   Json Configuration I/O.
+  */
+
+// C
+/** Use GNU C Library. */
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <sys/stat.h>
+
+// KernelShark
+#include "libkshark.h"
+#include "libkshark-model.h"
+
+/**
+ * @brief Create an empty Json document and set its type description.
+ *
+ * @param type: String describing the type of the document,
+ *		e.g. "kshark.record.config" or "kshark.filter.config".
+ *
+ * @returns json_object instance. Use json_object_put() to free the object.
+ */
+struct json_object *kshark_json_config_alloc(const char *type)
+{
+	json_object *jobj, *jtype;
+
+	jobj = json_object_new_object();
+	jtype = json_object_new_string(type);
+
+	if (!jobj || !jtype)
+		goto fail;
+
+	/* Set the type of this Json document. */
+	json_object_object_add(jobj, "type", jtype);
+
+	return jobj;
+
+ fail:
+	fprintf(stderr, "Failed to allocate memory for json_object.\n");
+	json_object_put(jobj);
+	json_object_put(jtype);
+
+	return NULL;
+}
+
+/**
+ * @brief Allocate kshark_config_doc and set its format.
+ *
+ * @param format: Input location for the Configuration format identifier.
+ *		  Currently only Json and String formats are supported.
+ *
+ * @returns kshark_config_doc instance on success. Else NULL. Use
+ *	    free() to free the object.
+ */
+struct kshark_config_doc *kshark_config_alloc(int format)
+{
+	struct kshark_config_doc *doc = NULL;
+
+	if (format == KS_JSON_CONFIG ||
+	    format == KS_STRING_CONFIG) {
+		doc = malloc(sizeof(*doc));
+		doc->format = format;
+		doc->conf_doc = NULL;
+	}
+
+	return doc;
+}
+
+/**
+ * @brief Create an empty Configuration document and set its format and type.
+ *
+ * @param type: String describing the type of the document,
+ *		e.g. "kshark.record.config" or "kshark.filter.config".
+ * @param format: Input location for the Configuration format identifier.
+ *		  Currently only Json format is supported.
+ *
+ * @returns kshark_config_doc instance on success. Else NULL. Use
+ *	    kshark_free_config_doc() to free the object.
+ */
+struct kshark_config_doc *kshark_config_new(const char *type, int format)
+{
+	struct kshark_config_doc *doc = NULL;
+
+	if (format == KS_JSON_CONFIG) {
+		doc = kshark_config_alloc(format);
+		doc->conf_doc = kshark_json_config_alloc(type);
+	}
+
+	return doc;
+}
+
+/**
+ * @brief Free the Configuration document.
+ *
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json and String formats are supported. It is safe to pass
+ *		a NULL value.
+ */
+void kshark_free_config_doc(struct kshark_config_doc *conf)
+{
+	if (!conf)
+		return;
+
+	if (conf->format == KS_JSON_CONFIG)
+		json_object_put(conf->conf_doc);
+
+	if (conf->format == KS_STRING_CONFIG)
+		free(conf->conf_doc);
+
+	free(conf);
+}
+
+/**
+ * @brief Use an existing Json document to create a new KernelShark
+ *	  Configuration document.
+ *
+ * @param jobj: Input location for the json_object instance.
+ *
+ * @returns shark_config_doc instance. Use kshark_free_config_doc() to free
+ *	    the object.
+ */
+struct kshark_config_doc *kshark_json_to_conf(struct json_object *jobj)
+{
+	struct kshark_config_doc *conf = malloc(sizeof(*conf));
+
+	conf->format = KS_JSON_CONFIG;
+	conf->conf_doc = jobj;
+
+	return conf;
+}
+
+/**
+ * @brief Use an existing string to create a new KernelShark Configuration
+ * document.
+ *
+ * @param val: Input location for the string.
+ *
+ * @returns kshark_config_doc instance. Use kshark_free_config_doc() to free
+ *	    the object.
+ */
+struct kshark_config_doc *kshark_string_to_conf(const char* val)
+{
+	struct kshark_config_doc *conf = malloc(sizeof(*conf));
+	char *str;
+
+	asprintf(&str, "%s", val);
+	conf->conf_doc = str;
+	conf->format = KS_STRING_CONFIG;
+
+	return conf;
+}
+
+/**
+ * @brief Add a field to a KernelShark Configuration document.
+ *
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ * @param key: The name of the field.
+ * @param val: Input location for the kshark_config_doc to be added.
+ *	       Currently only Json and String formats are supported.
+ */
+void kshark_config_doc_add(struct kshark_config_doc *conf,
+			   const char *key,
+			   struct kshark_config_doc *val)
+{
+	struct json_object *jobj;
+
+	if (!conf || !val)
+		return;
+
+	if (val->format == KS_NOFORMAT_CONFIG)
+		val->format = conf->format;
+
+	if (conf->format == KS_JSON_CONFIG) {
+		if (val->format == KS_JSON_CONFIG) {
+			json_object_object_add(conf->conf_doc, key,
+					       val->conf_doc);
+		}
+
+		if (val->format == KS_STRING_CONFIG) {
+			jobj = json_object_new_string(val->conf_doc);
+			json_object_object_add(conf->conf_doc, key, jobj);
+		}
+
+		free(val);
+	}
+}
+
+static bool get_jval(struct kshark_config_doc *conf,
+		     const char *key, void **val)
+{
+	return json_object_object_get_ex(conf->conf_doc, key,
+					 (json_object **) val);
+}
+
+/**
+ * @brief Get the KernelShark Configuration document associate with a given
+ *	  field name.
+ *
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ * @param key: The name of the field.
+ * @param val: Output location for the kshark_config_doc instance containing
+ *	       the field. Currently only Json and String formats are supported.
+ *
+ * @returns True, if the key exists. Else False.
+ */
+bool kshark_config_doc_get(struct kshark_config_doc *conf,
+			   const char *key,
+			   struct kshark_config_doc *val)
+{
+	if (!conf || !val)
+		return false;
+
+	if (val->format == KS_NOFORMAT_CONFIG)
+		val->format = conf->format;
+
+	if (conf->format == KS_JSON_CONFIG) {
+		if (val->format == KS_JSON_CONFIG) {
+			json_object_put(val->conf_doc);
+			return get_jval(conf, key, &val->conf_doc);
+		}
+
+		if (val->format == KS_STRING_CONFIG) {
+			struct kshark_config_doc *tmp;
+
+			free(val->conf_doc);
+
+			tmp = kshark_config_alloc(KS_JSON_CONFIG);
+			if (!get_jval(conf, key, &tmp->conf_doc))
+				return false;
+
+			val->conf_doc =
+				(char *) json_object_get_string(tmp->conf_doc);
+			free(tmp);
+
+			return true;
+		}
+	}
+
+	return false;
+}
+
+/**
+ * @brief Create an empty Record Configuration document. The type description
+ *	  is set to "kshark.record.config".
+ *
+ * @returns kshark_config_doc instance. Use kshark_free_config_doc() to free
+ *	    the object.
+ */
+struct kshark_config_doc *kshark_record_config_new(int format)
+{
+	return kshark_config_new("kshark.record.config", format);
+}
+
+/**
+ * @brief Create an empty Filter Configuration document. The type description
+ *	  is set to "kshark.filter.config".
+ *
+ * @returns kshark_config_doc instance. Use kshark_free_config_doc() to free
+ *	    the object.
+ */
+struct kshark_config_doc *kshark_filter_config_new(int format)
+{
+	return kshark_config_new("kshark.filter.config", format);
+}
+
+/**
+ * @brief Create an empty Data File Configuration document. The type
+ *	  description is set to "kshark.data.config".
+ *
+ * @returns kshark_config._doc instance. Use kshark_free_config_doc() to free
+ *	    the object
+ */
+struct kshark_config_doc *kshark_data_config_alloc(int format)
+{
+	return kshark_config_new("kshark.data.config", format);
+}
+
+/**
+ * @brief Create an empty Text Configuration document. The Text Configuration
+ *	  documents do not use type descriptions.
+ *
+ * @returns kshark_config_doc instance. Use free() to free the object.
+ */
+struct kshark_config_doc *kshark_string_config_alloc()
+{
+	return kshark_config_alloc(KS_STRING_CONFIG);
+}
+
+static void json_del_if_exist(struct json_object *jobj, const char *key)
+{
+	struct json_object *temp;
+	if (json_object_object_get_ex(jobj, key, &temp))
+	    json_object_object_del(jobj, key);
+}
+
+static bool json_check_type(struct json_object *jobj, const char *type)
+{
+	struct json_object *jtype;
+	const char *type_str;
+
+	if (!json_object_object_get_ex(jobj, "type", &jtype))
+		return false;
+
+	type_str = json_object_get_string(jtype);
+	if (strcmp(type_str, type) != 0)
+		return false;
+
+	return true;
+}
+
+static void kshark_trace_file_to_json(const char *file,
+				      struct json_object *jobj)
+{
+	struct json_object *jdata, *jfile_name, *jtime;
+	struct stat st;
+
+	if (!file || !jobj)
+		return;
+
+	/*
+	 * If this Json document already contains a descriprion of the data
+	 * source, delete this descriprion.
+	 */
+	json_del_if_exist(jobj, KS_DATA_SOURCE_NAME);
+
+	if (stat(file, &st) != 0) {
+		fprintf(stderr, "Unable to find file %s\n", file);
+		return;
+	}
+
+	jdata = kshark_json_config_alloc("kshark.data.config");
+	jfile_name = json_object_new_string(file);
+	jtime = json_object_new_int64(st.st_mtime);
+
+	if (!jdata || !jfile_name || !jtime)
+		goto fail;
+
+	json_object_object_add(jdata, "file", jfile_name);
+	json_object_object_add(jdata, "time", jtime);
+
+	json_object_object_add(jobj, KS_DATA_SOURCE_NAME, jdata);
+
+	return;
+
+ fail:
+	fprintf(stderr, "Failed to allocate memory for json_object.\n");
+	json_object_put(jdata);
+	json_object_put(jfile_name);
+	json_object_put(jtime);
+}
+
+/**
+ * @brief Record the name of a trace data file and its timestamp into a
+ *	  Configuration document.
+ *
+ * @param file: The name of the file.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ */
+void kshark_export_trace_file(const char *file,
+			      struct kshark_config_doc *conf)
+{
+	if (conf->format == KS_JSON_CONFIG)
+		kshark_trace_file_to_json(file, conf->conf_doc);
+}
+
+static bool kshark_trace_file_from_json(const char **file,
+					struct json_object *jobj)
+{
+	struct json_object *jdata, *jfile_name, *jtime;
+	const char *file_str;
+	struct stat st;
+	int64_t time;
+
+	if (!jobj)
+		return false;
+
+	if (!json_object_object_get_ex(jobj, KS_DATA_SOURCE_NAME, &jdata) ||
+	    !json_check_type(jdata, "kshark.data.config") ||
+	    !json_object_object_get_ex(jdata, "file", &jfile_name) ||
+	    !json_object_object_get_ex(jdata, "time", &jtime)) {
+		fprintf(stderr,
+			"Failed to retrieve data file from json_object.\n");
+		goto fail;
+	}
+
+	file_str = json_object_get_string(jfile_name);
+	time = json_object_get_int64(jtime);
+
+	if (stat(file_str, &st) != 0) {
+		fprintf(stderr, "Unable to find file %s\n", file_str);
+		goto fail;
+	}
+
+	if (st.st_mtime != time) {
+		fprintf(stderr,"Timestamp mismatch!\nFile %s", file_str);
+		fprintf(stderr," has been modified.\n");
+		goto fail;
+	}
+
+	*file = file_str;
+	printf("file_from_json: %s\n", *file);
+	return true;
+
+ fail:
+	json_object_put(jdata);
+	json_object_put(jfile_name);
+	json_object_put(jtime);
+
+	return false;
+}
+
+/**
+ * @brief Read the name of a trace data file and its timestamp from a
+ *	  Configuration document and check if this file exists.
+ *
+ * @param file: Output location for the name of the file.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ *
+ * @returns True, if the Configuration document contains a trace data file
+ *	    record and if such a file exists. Else False.
+ */
+bool kshark_import_trace_file(const char **file,
+			      struct kshark_config_doc *conf)
+{
+	if (conf->format == KS_JSON_CONFIG) {
+		if (kshark_trace_file_from_json(file, conf->conf_doc))
+			return true;
+	}
+
+	return false;
+}
+
+static void kshark_model_to_json(struct kshark_trace_histo *histo,
+				 struct json_object *jobj)
+{
+	struct json_object *jmodel, *jrange, *jmin, *jmax, *jn_bins;
+	if (!histo || !jobj)
+		return;
+
+	/*
+	 * If this Json document already contains a descriprion of the model,
+	 * delete this descriprion.
+	 */
+	json_del_if_exist(jobj, KS_HISTO_NAME);
+
+	jmodel = kshark_json_config_alloc("kshark.model.config");
+	jrange = json_object_new_array();
+
+	jmin = json_object_new_int64(histo->min);
+	jmax = json_object_new_int64(histo->max);
+	jn_bins = json_object_new_int(histo->n_bins);
+
+	if (!jmodel || !jrange || !jmin || !jmax || !jn_bins)
+		goto fail;
+
+	json_object_array_put_idx(jrange, 0, jmin);
+	json_object_array_put_idx(jrange, 1, jmax);
+
+	json_object_object_add(jmodel, "range", jrange);
+	json_object_object_add(jmodel, "bins", jn_bins);
+
+	json_object_object_add(jobj, KS_HISTO_NAME, jmodel);
+
+	return;
+
+ fail:
+	fprintf(stderr, "Failed to allocate memory for json_object.\n");
+	json_object_put(jmodel);
+	json_object_put(jrange);
+	json_object_put(jmin);
+	json_object_put(jmax);
+	json_object_put(jn_bins);
+}
+
+/**
+ * @brief Record the current configuration of the Vis. model into a
+ *	  Configuration document.
+ * Load the configuration of the Vis. model from a Configuration
+ *	  document.
+ *
+ * @param histo: Input location for the Vis. model descriptor.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ */
+void kshark_export_model(struct kshark_trace_histo *histo,
+			 struct kshark_config_doc *conf)
+{
+	if (conf->format == KS_JSON_CONFIG)
+		kshark_model_to_json(histo, conf->conf_doc);
+}
+
+static bool kshark_model_from_json(struct kshark_trace_histo *histo,
+				   struct json_object *jobj)
+{
+	struct json_object *jmodel, *jrange, *jmin, *jmax, *jn_bins;
+	uint64_t min, max;
+	int n_bins;
+
+	if (!histo || !jobj)
+		return false;
+
+	if (!json_object_object_get_ex(jobj, KS_HISTO_NAME, &jmodel))
+		goto fail;
+
+	if (!json_check_type(jmodel, "kshark.model.config"))
+		goto fail;
+
+	if (!json_object_object_get_ex(jmodel, "range", &jrange))
+		goto fail;
+
+	if (json_object_get_type(jrange) != json_type_array)
+		goto fail;
+
+	jmin = json_object_array_get_idx(jrange, 0);
+	jmax = json_object_array_get_idx(jrange, 1);
+	if (!jmin || !jmax)
+		goto fail;
+
+	if (!json_object_object_get_ex(jmodel, "bins", &jn_bins))
+		goto fail;
+
+	min = json_object_get_int64(jmin);
+	max = json_object_get_int64(jmax);
+	n_bins = json_object_get_int(jn_bins);
+	ksmodel_set_bining(histo, n_bins, min, max);
+
+	if (histo->data && histo->data_size)
+		ksmodel_fill(histo, histo->data, histo->data_size);
+
+	return true;
+
+ fail:
+	fprintf(stderr, "Failed to load event filter from json_object.\n");
+	return false;
+}
+
+/**
+ * @brief Load the configuration of the Vis. model from a Configuration
+ *	  document.
+ *
+ * @param histo: Input location for the Vis. model descriptor.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ */
+void kshark_import_model(struct kshark_trace_histo *histo,
+			 struct kshark_config_doc *conf)
+{
+	if (conf->format == KS_JSON_CONFIG)
+		kshark_model_from_json(histo, conf->conf_doc);
+}
+
+static void kshark_event_filter_to_json(struct pevent *pevent,
+					struct tracecmd_filter_id *filter,
+					const char *filter_name,
+					struct json_object *jobj)
+{
+	json_object *jfilter_data, *jevent, *jsystem, *jname;
+	int i, evt, *ids;
+	char *temp;
+
+	/*
+	 * If this Json document already contains a descriprion of the filter,
+	 * delete this descriprion.
+	 */
+	json_del_if_exist(jobj, filter_name);
+
+
+	/* Get the array of Ids to be fitered. */
+	ids = tracecmd_filter_ids(filter);
+	if (!ids)
+		return;
+
+	/* Create a Json array and fill the Id values into it. */
+	jfilter_data = json_object_new_array();
+	if (!jfilter_data)
+		goto fail;
+
+	for (i = 0; i < filter->count; ++i) {
+		for (evt = 0; evt < pevent->nr_events; ++evt) {
+			if (pevent->events[evt]->id == ids[i]) {
+				jevent = json_object_new_object();
+
+				temp = pevent->events[evt]->system;
+				jsystem = json_object_new_string(temp);
+
+				temp = pevent->events[evt]->name;
+				jname = json_object_new_string(temp);
+
+				if (!jevent || !jsystem || !jname)
+					goto fail;
+
+				json_object_object_add(jevent, "system",
+							       jsystem);
+
+				json_object_object_add(jevent, "name",
+							       jname);
+
+				json_object_array_add(jfilter_data, jevent);
+
+				break;
+			}
+		}
+	}
+
+	free(ids);
+
+	/* Add the array of Ids to the filter config document. */
+	json_object_object_add(jobj, filter_name, jfilter_data);
+
+	return;
+
+ fail:
+	fprintf(stderr, "Failed to allocate memory for json_object.\n");
+	json_object_put(jfilter_data);
+	json_object_put(jevent);
+	json_object_put(jsystem);
+	json_object_put(jname);
+	free(ids);
+}
+
+/**
+ * @brief Record the current configuration of an Event Id filter into a
+ *	  Configuration document.
+ *
+ * @param pevent: Input location for the Page event.
+ * @param filter: Input location for an Id filter.
+ * @param filter_name: The name of the filter to show up in the Json document.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ */
+void kshark_export_event_filter(struct pevent *pevent,
+				struct tracecmd_filter_id *filter,
+				const char *filter_name,
+				struct kshark_config_doc *conf)
+{
+	if (conf->format == KS_JSON_CONFIG)
+		kshark_event_filter_to_json(pevent, filter, filter_name,
+					    conf->conf_doc);
+}
+
+static bool kshark_event_filter_from_json(struct pevent *pevent,
+					  struct tracecmd_filter_id *filter,
+					  const char *filter_name,
+					  struct json_object *jobj)
+{
+	json_object *jfilter, *jevent, *jsystem, *jname;
+	const char *system_str, *name_str;
+	struct event_format *event;
+	int i, length;
+
+	/*
+	 * Use the name of the filter to find the array of events associated
+	 * with this filter. Notice that the filter config document may
+	 * contain no data for this particular filter.
+	 */
+	if (!json_object_object_get_ex(jobj, filter_name, &jfilter))
+		return false;
+
+	if (!json_check_type(jobj, "kshark.filter.config") ||
+	    json_object_get_type(jfilter) != json_type_array)
+		goto fail;
+
+	/* Set the filter. */
+	length = json_object_array_length(jfilter);
+	for (i = 0; i < length; ++i) {
+		jevent = json_object_array_get_idx(jfilter, i);
+
+		if (!json_object_object_get_ex(jevent, "system", &jsystem))
+			goto fail;
+
+		if (!json_object_object_get_ex(jevent, "name", &jname))
+			goto fail;
+
+		system_str = json_object_get_string(jsystem);
+		name_str = json_object_get_string(jname);
+
+		event = pevent_find_event_by_name(pevent, system_str, name_str);
+		if (!event)
+			goto fail;
+
+		tracecmd_filter_id_add(filter, event->id);
+	}
+
+	return true;
+
+ fail:
+	fprintf(stderr, "Failed to load event filter from json_object.\n");
+	return false;
+}
+
+/**
+ * @brief Load from Configuration document the configuration of an Event Id filter.
+ *
+ * @param pevent: Input location for the Page event.
+ * @param filter: Input location for an Id filter.
+ * @param filter_name: The name of the filter as showing up in the Config.
+ *	               document.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ *
+ * @returns True, if a filter has been loaded. If the filter configuration
+ *	    document contains no data for this particular filter or in a case
+ *	    of an error, the function returns False.
+ */
+bool kshark_import_event_filter(struct pevent *pevent,
+				struct tracecmd_filter_id *filter,
+				const char *filter_name,
+				struct kshark_config_doc *conf)
+{
+	if (conf->format == KS_JSON_CONFIG)
+		return kshark_event_filter_from_json(pevent, filter,
+						     filter_name,
+						     conf->conf_doc);
+
+	return false;
+}
+
+static void kshark_task_filter_to_json(struct tracecmd_filter_id *filter,
+				       const char *filter_name,
+				       struct json_object *jobj)
+{
+	json_object *jfilter_data, *jpid;
+	int i, *ids;
+
+	/*
+	 * If this Json document already contains a descriprion of the model,
+	 * delete this descriprion.
+	 */
+	json_del_if_exist(jobj, filter_name);
+
+	/* Get the array of Ids to be fitered. */
+	ids = tracecmd_filter_ids(filter);
+	if (!ids)
+		return;
+
+	/* Create a Json array and fill the Id values into it. */
+	jfilter_data = json_object_new_array();
+	if (!jfilter_data)
+		goto fail;
+
+	for (i = 0; i < filter->count; ++i) {
+		jpid = json_object_new_int(ids[i]);
+		if (!jpid)
+			goto fail;
+
+		json_object_array_add(jfilter_data, jpid);
+	}
+
+	free(ids);
+
+	/* Add the array of Ids to the filter config document. */
+	json_object_object_add(jobj, filter_name, jfilter_data);
+
+	return;
+
+ fail:
+	fprintf(stderr, "Failed to allocate memory for json_object.\n");
+	json_object_put(jfilter_data);
+	json_object_put(jpid);
+	free(ids);
+}
+
+/**
+ * @brief Record the current configuration of a Task Id filter into a
+ *	  Configuration document.
+ *
+ * @param filter: Input location for an Id filter.
+ * @param filter_name: The name of the filter to show up in the Json document.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ */
+void kshark_export_task_filter(struct tracecmd_filter_id *filter,
+			       const char *filter_name,
+			       struct kshark_config_doc *conf)
+{
+	if (conf->format == KS_JSON_CONFIG)
+		kshark_task_filter_to_json(filter, filter_name,
+					   conf->conf_doc);
+}
+
+static bool kshark_task_filter_from_json(struct tracecmd_filter_id *filter,
+					 const char *filter_name,
+					 struct json_object *jobj)
+{
+	json_object *jfilter, *jpid;
+	int i, length;
+
+	/*
+	 * Use the name of the filter to find the array of events associated
+	 * with this filter. Notice that the filter config document may
+	 * contain no data for this particular filter.
+	 */
+	if (!json_object_object_get_ex(jobj, filter_name, &jfilter))
+		return false;
+
+	if (!json_check_type(jobj, "kshark.filter.config") ||
+	    json_object_get_type(jfilter) != json_type_array)
+		goto fail;
+
+	/* Set the filter. */
+	length = json_object_array_length(jfilter);
+	for (i = 0; i < length; ++i) {
+		jpid = json_object_array_get_idx(jfilter, i);
+		if (!jpid)
+			goto fail;
+
+		tracecmd_filter_id_add(filter, json_object_get_int(jpid));
+	}
+
+	return true;
+
+ fail:
+	fprintf(stderr, "Failed to load task filter from json_object.\n");
+	return false;
+}
+
+/**
+ * @brief Load from Configuration document the configuration of a Task Id filter.
+ *
+ * @param filter: Input location for an Id filter.
+ * @param filter_name: The name of the filter as showing up in the Config.
+ *	               document.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ *
+ * @returns True, if a filter has been loaded. If the filter configuration
+ *	    document contains no data for this particular filter or in a case
+ *	    of an error, the function returns False.
+ */
+bool kshark_import_task_filter(struct tracecmd_filter_id *filter,
+			       const char *filter_name,
+			       struct kshark_config_doc *conf)
+{
+	if (conf->format == KS_JSON_CONFIG)
+		return kshark_task_filter_from_json(filter, filter_name,
+						    conf->conf_doc);
+
+	return false;
+}
+
+static void kshark_adv_filters_to_json(struct kshark_context *kshark_ctx,
+				       struct json_object *jobj)
+{
+	struct event_filter *adv_filter = kshark_ctx->advanced_event_filter;
+	json_object *jfilter_data, *jevent, *jsystem, *jname, *jfilter;
+	struct event_format **events;
+	char *str;
+	int i;
+
+	/*
+	 * If this Json document already contains a descriprion of the model,
+	 * delete this descriprion.
+	 */
+	json_del_if_exist(jobj, KS_ADV_EVENT_FILTER_NAME);
+
+	if (!kshark_ctx->advanced_event_filter ||
+	    !kshark_ctx->advanced_event_filter->filters)
+		return;
+
+	/* Create a Json array and fill the Id values into it. */
+	jfilter_data = json_object_new_array();
+	if (!jfilter_data)
+		goto fail;
+
+	events = pevent_list_events(kshark_ctx->pevent, EVENT_SORT_SYSTEM);
+	if (!events)
+		return;
+
+	for (i = 0; events[i]; i++) {
+		str = pevent_filter_make_string(adv_filter,
+						events[i]->id);
+		if (!str)
+			continue;
+
+		jevent = json_object_new_object();
+		jsystem = json_object_new_string(events[i]->system);
+		jname = json_object_new_string(events[i]->name);
+		jfilter = json_object_new_string(str);
+		if (!jevent || !jsystem || !jname || !jfilter)
+			goto fail;
+
+		json_object_object_add(jevent, "system", jsystem);
+		json_object_object_add(jevent, "name", jname);
+		json_object_object_add(jevent, "condition", jfilter);
+
+		json_object_array_add(jfilter_data, jevent);
+	}
+
+	/* Add the array of advanced filters to the filter config document. */
+	json_object_object_add(jobj, KS_ADV_EVENT_FILTER_NAME, jfilter_data);
+
+	return;
+
+ fail:
+	fprintf(stderr, "Failed to allocate memory for json_object.\n");
+	json_object_put(jfilter_data);
+	json_object_put(jevent);
+	json_object_put(jsystem);
+	json_object_put(jname);
+	json_object_put(jfilter);
+}
+
+/**
+ * @brief Record the current configuration of the advanced filter into a
+ *	  Configuration document.
+ *
+ * @param kshark_ctx: Input location for session context pointer.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported. If NULL, a new Adv. Filter
+ *		Configuration document will be created.
+ */
+void kshark_export_adv_filters(struct kshark_context *kshark_ctx,
+			       struct kshark_config_doc **conf)
+{
+	if (!*conf)
+		*conf = kshark_filter_config_new(KS_JSON_CONFIG);
+
+	if ((*conf)->format == KS_JSON_CONFIG)
+		kshark_adv_filters_to_json(kshark_ctx, (*conf)->conf_doc);
+}
+
+static bool kshark_adv_filters_from_json(struct kshark_context *kshark_ctx,
+					 struct json_object *jobj)
+{
+	struct event_filter *adv_filter = kshark_ctx->advanced_event_filter;
+	json_object *jfilter, *jsystem, *jname, *jcond;
+	int i, length, ret;
+	char *filter_str;
+
+	/*
+	 * Use the name of the filter to find the array of events associated
+	 * with this filter. Notice that the filter config document may
+	 * contain no data for this particular filter.
+	 */
+	if (!json_object_object_get_ex(jobj, KS_ADV_EVENT_FILTER_NAME,
+				       &jfilter))
+		return false;
+
+	if (!json_check_type(jobj, "kshark.filter.config") ||
+	    json_object_get_type(jfilter) != json_type_array)
+		goto fail;
+
+	/* Set the filter. */
+	length = json_object_array_length(jfilter);
+	for (i = 0; i < length; ++i) {
+		jfilter = json_object_array_get_idx(jfilter, i);
+
+		if (!json_object_object_get_ex(jfilter, "system", &jsystem))
+			goto fail;
+
+		if (!json_object_object_get_ex(jfilter, "name", &jname))
+			goto fail;
+
+		if (!json_object_object_get_ex(jfilter, "condition", &jcond))
+			goto fail;
+
+		asprintf(&filter_str, "%s/%s:%s",
+			 json_object_get_string(jsystem),
+			 json_object_get_string(jname),
+			 json_object_get_string(jcond));
+
+		ret = pevent_filter_add_filter_str(adv_filter,
+						   filter_str);
+		if (ret < 0)
+			goto fail;
+	}
+
+	return true;
+
+ fail:
+	fprintf(stderr, "Failed to laod Advanced filters.\n");
+	char error_str[200];
+	int error_status =
+		pevent_strerror(kshark_ctx->pevent, ret, error_str,
+							 sizeof(error_str));
+
+	if (error_status == 0)
+		fprintf(stderr, "filter failed due to: %s\n", error_str);
+
+	free(filter_str);
+	return false;
+}
+
+/**
+ * @brief Load from Configuration document the configuration of the advanced
+ *	  filter.
+ *
+ * @param kshark_ctx: Input location for session context pointer.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ *
+ * @returns True, if a filter has been loaded. If the filter configuration
+ *	    document contains no data for this particular filter or in a case
+ *	    of an error, the function returns False.
+ */
+bool kshark_import_adv_filters(struct kshark_context *kshark_ctx,
+			       struct kshark_config_doc *conf)
+{
+	if (conf->format == KS_JSON_CONFIG)
+		return kshark_adv_filters_from_json(kshark_ctx,
+						    conf->conf_doc);
+
+	return false;
+}
+
+static bool filter_is_set(struct tracecmd_filter_id *filter)
+{
+	return filter && filter->count;
+}
+
+/**
+ * @brief Record the current configuration of "show task" and "hide task"
+ *	  filters into a Json document.
+ *
+ * @param kshark_ctx: Input location for session context pointer.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported. If NULL, a new Filter
+ *		Configuration document will be created.
+ */
+void kshark_export_all_event_filters(struct kshark_context *kshark_ctx,
+				     struct kshark_config_doc **conf)
+{
+	if (!*conf)
+		*conf = kshark_filter_config_new(KS_JSON_CONFIG);
+
+	/* Save a filter only if it contains Id values. */
+	if (filter_is_set(kshark_ctx->show_event_filter))
+		kshark_export_event_filter(kshark_ctx->pevent,
+					   kshark_ctx->show_event_filter,
+					   KS_SHOW_EVENT_FILTER_NAME,
+					   *conf);
+
+	if (filter_is_set(kshark_ctx->hide_event_filter))
+		kshark_export_event_filter(kshark_ctx->pevent,
+					   kshark_ctx->hide_event_filter,
+					   KS_HIDE_EVENT_FILTER_NAME,
+					   *conf);
+}
+
+/**
+ * @brief Record the current configuration of "show task" and "hide task"
+ *	  filters into a Configuration document.
+ *
+ * @param kshark_ctx: Input location for session context pointer.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported. If NULL, a new Filter
+ *		Configuration document will be created.
+ */
+void kshark_export_all_task_filters(struct kshark_context *kshark_ctx,
+				    struct kshark_config_doc **conf)
+{
+	if (!*conf)
+		*conf = kshark_filter_config_new(KS_JSON_CONFIG);
+
+	/* Save a filter only if it contains Id values. */
+	if (filter_is_set(kshark_ctx->show_task_filter))
+		kshark_export_task_filter(kshark_ctx->show_task_filter,
+					  KS_SHOW_TASK_FILTER_NAME,
+					  *conf);
+
+	if (filter_is_set(kshark_ctx->hide_task_filter))
+		kshark_export_task_filter(kshark_ctx->hide_task_filter,
+					  KS_HIDE_TASK_FILTER_NAME,
+					  *conf);
+}
+
+/**
+ * @brief Load from a Configuration document the configuration of "show event"
+ *	  and "hide event" filters.
+ *
+ * @param kshark_ctx: Input location for session context pointer.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ *
+ * @returns True, if a filter has been loaded. If the filter configuration
+ *	    document contains no data for any event filter or in a case
+ *	    of an error, the function returns False.
+ */
+bool kshark_import_all_event_filters(struct kshark_context *kshark_ctx,
+				     struct kshark_config_doc *conf)
+{
+	bool status;
+
+	status = kshark_import_event_filter(kshark_ctx->pevent,
+					    kshark_ctx->hide_event_filter,
+					    KS_HIDE_EVENT_FILTER_NAME,
+					    conf);
+
+	status |= kshark_import_event_filter(kshark_ctx->pevent,
+					     kshark_ctx->show_event_filter,
+					     KS_SHOW_EVENT_FILTER_NAME,
+					     conf);
+
+	return status;
+}
+
+/**
+ * @brief Load from Configuration document the configuration of "show task"
+ *	  and "hide task" filters.
+ *
+ * @param kshark_ctx: Input location for session context pointer.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ *
+ * @returns True, if a filter has been loaded. If the filter configuration
+ *	    document contains no data for any task filter or in a case of an
+ *	    error, the function returns False.
+ */
+bool kshark_import_all_task_filters(struct kshark_context *kshark_ctx,
+				    struct kshark_config_doc *conf)
+{
+	bool status;
+
+	status = kshark_import_task_filter(kshark_ctx->hide_task_filter,
+					   KS_HIDE_TASK_FILTER_NAME,
+					   conf);
+
+	status |= kshark_import_task_filter(kshark_ctx->show_task_filter,
+					    KS_SHOW_TASK_FILTER_NAME,
+					    conf);
+
+	return status;
+}
+
+/**
+ * @brief Create a Filter Configuration document containing the current
+ *	  configuration of all filters.
+ *
+ * @param kshark_ctx: Input location for session context pointer.
+ *
+ * @returns kshark_config_doc instance. Use kshark_free_config_doc() to free
+ *	    the object.
+ */
+struct kshark_config_doc *
+kshark_export_all_filters(struct kshark_context *kshark_ctx)
+{
+	/*  Create a new Configuration document. */
+	struct kshark_config_doc *conf =
+		kshark_filter_config_new(KS_JSON_CONFIG);
+
+	/* Save a filter only if it contains Id values. */
+	kshark_export_all_event_filters(kshark_ctx, &conf);
+	kshark_export_all_task_filters(kshark_ctx, &conf);
+	kshark_export_adv_filters(kshark_ctx, &conf);
+
+	return conf;
+}
+
+/**
+ * @brief Load from a Configuration document the configuration of all filters.
+ *
+ * @param kshark_ctx: Input location for session context pointer.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ *
+ * @returns True, if a filter has been loaded. If the filter configuration
+ *	    document contains no data for any filter or in a case of an error,
+ *	    the function returns False.
+ */
+bool kshark_import_all_filters(struct kshark_context *kshark_ctx,
+			       struct kshark_config_doc *conf)
+{
+	bool status;
+	status = kshark_import_all_task_filters(kshark_ctx, conf);
+	status |= kshark_import_all_event_filters(kshark_ctx, conf);
+	status |= kshark_import_adv_filters(kshark_ctx, conf);
+
+	return status;
+}
+
+static void kshark_save_json_file(const char *file_name,
+				  struct json_object *jobj)
+{
+	int flags;
+
+	/* Save the file in a human-readable form. */
+	flags = JSON_C_TO_STRING_SPACED | JSON_C_TO_STRING_PRETTY;
+	json_object_to_file_ext(file_name, jobj, flags);
+}
+
+/**
+ * @brief Save a Configuration document into a file.
+ *
+ * @param file_name: The name of the file.
+ * @param conf: Input location for the kshark_config_doc instance. Currently
+ *		only Json format is supported.
+ */
+void kshark_save_config_file(const char *file_name,
+			     struct kshark_config_doc *conf)
+{
+	if (conf->format == KS_JSON_CONFIG)
+		kshark_save_json_file(file_name, conf->conf_doc);
+}
+
+static struct json_object *kshark_open_json_file(const char *file_name,
+						 const char *type)
+{
+	struct json_object *jobj, *var;
+	const char *type_var;
+
+	jobj = json_object_from_file(file_name);
+
+	if (!jobj)
+		return NULL;
+
+	/* Get the type of the document. */
+	if (!json_object_object_get_ex(jobj, "type", &var))
+		goto fail;
+
+	type_var = json_object_get_string(var);
+
+	if (strcmp(type, type_var) != 0)
+		goto fail;
+
+	return jobj;
+
+ fail:
+	/* The document has a wrong type. */
+	fprintf(stderr, "Failed to open Json file %s\n.", file_name);
+	fprintf(stderr, "The document has a wrong type.\n");
+
+	json_object_put(jobj);
+	return NULL;
+}
+
+static const char *get_ext(const char *filename)
+{
+	const char *dot = strrchr(filename, '.');
+
+	if(!dot)
+		return "unknown";
+
+	return dot + 1;
+}
+
+/**
+ * @brief Open a for read a Configuration file and check if it has the
+ *	  expected type.
+ *
+ * @param file_name: The name of the file. Currently only Json files are
+ *		     supported.
+ * @param type: String describing the expected type of the document,
+ *		e.g. "kshark.record.config" or "kshark.filter.config".
+ *
+ * @returns kshark_config_doc instance on success, or NULL on failure. Use
+ *	    kshark_free_config_doc() to free the object.
+ */
+struct kshark_config_doc *kshark_open_config_file(const char *file_name,
+						  const char *type)
+{
+	struct kshark_config_doc *conf = NULL;
+
+	if (strcmp(get_ext(file_name), "json") == 0) {
+		struct json_object *jobj =
+			kshark_open_json_file(file_name, type);
+
+		if (jobj) {
+			conf = malloc(sizeof(*conf));
+			conf->conf_doc = jobj;
+			conf->format = KS_JSON_CONFIG;
+		}
+	}
+
+	return conf;
+}
diff --git a/kernel-shark-qt/src/libkshark.h b/kernel-shark-qt/src/libkshark.h
index ff09da3..4fe4420 100644
--- a/kernel-shark-qt/src/libkshark.h
+++ b/kernel-shark-qt/src/libkshark.h
@@ -16,6 +16,9 @@ 
 #include <stdint.h>
 #include <pthread.h>
 
+// Json-C
+#include <json.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -367,6 +370,155 @@  kshark_get_collection_entry_back(struct kshark_entry_request **req,
 				 const struct kshark_entry_collection *col,
 				 ssize_t *index);
 
+/** Structure representing a KernelShark Configuration document. */
+struct kshark_config_doc {
+	/** Document format identifier. */
+	int	format;
+
+	/** Configuration document instance. */
+	void	*conf_doc;
+};
+
+/** Configuration format identifiers. */
+enum kshark_config_formats {
+	/** Unformatted Configuration document identifier. */
+	KS_NOFORMAT_CONFIG = 0,
+
+	/**
+	 * String Configuration document identifier. The String format is
+	 * meant to be used only by kshark_config_doc_add() and
+	 * kshark_config_doc_get(), when adding/getting simple string fields.
+	 */
+	KS_STRING_CONFIG,
+
+	/** Json Configuration document identifier. */
+	KS_JSON_CONFIG,
+};
+
+/**
+ * Field name for the Configuration document describing the Hide Event filter.
+ */
+#define KS_HIDE_EVENT_FILTER_NAME	"hide event filter"
+
+/**
+ * Field name for the Configuration document describing the Show Event filter.
+ */
+#define KS_SHOW_EVENT_FILTER_NAME	"show event filter"
+
+/**
+ * Field name for the Configuration document describing the Hide Task filter.
+ */
+#define KS_HIDE_TASK_FILTER_NAME	"hide task filter"
+
+/**
+ * Field name for the Configuration document describing the Show Task filter.
+ */
+#define KS_SHOW_TASK_FILTER_NAME	"show task filter"
+
+/**
+ * Field name for the Configuration document describing the Advanced event
+ * filter.
+ */
+#define KS_ADV_EVENT_FILTER_NAME	"adv event filter"
+
+/**
+ * Field name for the Configuration document describing the state of the Vis.
+ * model.
+ */
+#define KS_HISTO_NAME			"vis. model"
+
+/**
+ * Field name for the Configuration document describing the currently loaded
+ * trace data file.
+ */
+#define KS_DATA_SOURCE_NAME		"trace data"
+
+struct json_object *kshark_json_config_alloc(const char *type);
+
+struct kshark_config_doc *kshark_config_alloc(int format);
+
+struct kshark_config_doc *kshark_config_new(const char *type, int format);
+
+void kshark_free_config_doc(struct kshark_config_doc *conf);
+
+struct kshark_config_doc *kshark_record_config_new(int format);
+
+struct kshark_config_doc *kshark_filter_config_new(int format);
+
+struct kshark_config_doc *kshark_string_config_alloc();
+
+void kshark_config_doc_add(struct kshark_config_doc *conf,
+			   const char *key,
+			   struct kshark_config_doc *val);
+
+bool kshark_config_doc_get(struct kshark_config_doc *conf,
+			   const char *key,
+			   struct kshark_config_doc *val);
+
+struct kshark_trace_histo;
+
+void kshark_export_trace_file(const char *file,
+			      struct kshark_config_doc *conf);
+
+bool kshark_import_trace_file(const char **file,
+			      struct kshark_config_doc *conf);
+
+void kshark_export_model(struct kshark_trace_histo *histo,
+			 struct kshark_config_doc *conf);
+
+void kshark_import_model(struct kshark_trace_histo *histo,
+			 struct kshark_config_doc *conf);
+
+void kshark_export_adv_filters(struct kshark_context *kshark_ctx,
+			       struct kshark_config_doc **conf);
+
+bool kshark_import_adv_filters(struct kshark_context *kshark_ctx,
+			       struct kshark_config_doc *conf);
+
+void kshark_export_event_filter(struct pevent *pevent,
+				struct tracecmd_filter_id *filter,
+				const char *filter_name,
+				struct kshark_config_doc *conf);
+
+bool kshark_import_event_filter(struct pevent *pevent,
+				struct tracecmd_filter_id *filter,
+				const char *filter_name,
+				struct kshark_config_doc *conf);
+
+void kshark_export_task_filter(struct tracecmd_filter_id *filter,
+			       const char *filter_name,
+			       struct kshark_config_doc *conf);
+
+bool kshark_import_task_filter(struct tracecmd_filter_id *filter,
+			       const char *filter_name,
+			       struct kshark_config_doc *conf);
+
+void kshark_export_all_event_filters(struct kshark_context *kshark_ctx,
+				     struct kshark_config_doc **conf);
+
+void kshark_export_all_task_filters(struct kshark_context *kshark_ctx,
+				    struct kshark_config_doc **conf);
+
+struct kshark_config_doc *
+kshark_export_all_filters(struct kshark_context *kshark_ctx);
+
+bool kshark_import_all_event_filters(struct kshark_context *kshark_ctx,
+				     struct kshark_config_doc *conf);
+
+bool kshark_import_all_task_filters(struct kshark_context *kshark_ctx,
+				    struct kshark_config_doc *conf);
+
+bool kshark_import_all_filters(struct kshark_context *kshark_ctx,
+			       struct kshark_config_doc *conf);
+
+void kshark_save_config_file(const char *file_name,
+			     struct kshark_config_doc *conf);
+
+struct kshark_config_doc *kshark_open_config_file(const char *file_name,
+						  const char *type);
+
+struct kshark_config_doc *kshark_json_to_conf(struct json_object *jobj);
+
 #ifdef __cplusplus
 }
 #endif