[v2,03/17] kunit: test: add string_stream a std::stream like string builder
diff mbox series

Message ID 20190501230126.229218-4-brendanhiggins@google.com
State New
Headers show
Series
  • kunit: introduce KUnit, the Linux kernel unit testing framework
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Commit Message

Brendan Higgins May 1, 2019, 11:01 p.m. UTC
A number of test features need to do pretty complicated string printing
where it may not be possible to rely on a single preallocated string
with parameters.

So provide a library for constructing the string as you go similar to
C++'s std::string.

Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
---
 include/kunit/string-stream.h |  51 ++++++++++++
 kunit/Makefile                |   3 +-
 kunit/string-stream.c         | 144 ++++++++++++++++++++++++++++++++++
 3 files changed, 197 insertions(+), 1 deletion(-)
 create mode 100644 include/kunit/string-stream.h
 create mode 100644 kunit/string-stream.c

Comments

shuah May 3, 2019, 1:26 a.m. UTC | #1
On 5/1/19 5:01 PM, Brendan Higgins wrote:
> A number of test features need to do pretty complicated string printing
> where it may not be possible to rely on a single preallocated string
> with parameters.
> 
> So provide a library for constructing the string as you go similar to
> C++'s std::string.
> 
> Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
> ---
>   include/kunit/string-stream.h |  51 ++++++++++++
>   kunit/Makefile                |   3 +-
>   kunit/string-stream.c         | 144 ++++++++++++++++++++++++++++++++++
>   3 files changed, 197 insertions(+), 1 deletion(-)
>   create mode 100644 include/kunit/string-stream.h
>   create mode 100644 kunit/string-stream.c
> 
> diff --git a/include/kunit/string-stream.h b/include/kunit/string-stream.h
> new file mode 100644
> index 0000000000000..567a4629406da
> --- /dev/null
> +++ b/include/kunit/string-stream.h
> @@ -0,0 +1,51 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * C++ stream style string builder used in KUnit for building messages.
> + *
> + * Copyright (C) 2019, Google LLC.
> + * Author: Brendan Higgins <brendanhiggins@google.com>
> + */
> +
> +#ifndef _KUNIT_STRING_STREAM_H
> +#define _KUNIT_STRING_STREAM_H
> +
> +#include <linux/types.h>
> +#include <linux/spinlock.h>
> +#include <linux/kref.h>
> +#include <stdarg.h>
> +
> +struct string_stream_fragment {
> +	struct list_head node;
> +	char *fragment;
> +};
> +
> +struct string_stream {
> +	size_t length;
> +	struct list_head fragments;
> +
> +	/* length and fragments are protected by this lock */
> +	spinlock_t lock;
> +	struct kref refcount;
> +};
> +
> +struct string_stream *new_string_stream(void);
> +
> +void destroy_string_stream(struct string_stream *stream);
> +
> +void string_stream_get(struct string_stream *stream);
> +
> +int string_stream_put(struct string_stream *stream);
> +
> +int string_stream_add(struct string_stream *this, const char *fmt, ...);
> +
> +int string_stream_vadd(struct string_stream *this,
> +		       const char *fmt,
> +		       va_list args);
> +
> +char *string_stream_get_string(struct string_stream *this);
> +
> +void string_stream_clear(struct string_stream *this);
> +
> +bool string_stream_is_empty(struct string_stream *this);
> +
> +#endif /* _KUNIT_STRING_STREAM_H */
> diff --git a/kunit/Makefile b/kunit/Makefile
> index 5efdc4dea2c08..275b565a0e81f 100644
> --- a/kunit/Makefile
> +++ b/kunit/Makefile
> @@ -1 +1,2 @@
> -obj-$(CONFIG_KUNIT) +=			test.o
> +obj-$(CONFIG_KUNIT) +=			test.o \
> +					string-stream.o
> diff --git a/kunit/string-stream.c b/kunit/string-stream.c
> new file mode 100644
> index 0000000000000..7018194ecf2fa
> --- /dev/null
> +++ b/kunit/string-stream.c
> @@ -0,0 +1,144 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * C++ stream style string builder used in KUnit for building messages.
> + *
> + * Copyright (C) 2019, Google LLC.
> + * Author: Brendan Higgins <brendanhiggins@google.com>
> + */
> +
> +#include <linux/list.h>
> +#include <linux/slab.h>
> +#include <kunit/string-stream.h>
> +
> +int string_stream_vadd(struct string_stream *this,
> +		       const char *fmt,
> +		       va_list args)
> +{
> +	struct string_stream_fragment *fragment;

Since there is field with the same name, please use a different
name. Using the same name for the struct which contains a field
of the same name get very confusing and will hard to maintain
the code.

> +	int len;
> +	va_list args_for_counting;
> +	unsigned long flags;
> +
> +	/* Make a copy because `vsnprintf` could change it */
> +	va_copy(args_for_counting, args);
> +
> +	/* Need space for null byte. */
> +	len = vsnprintf(NULL, 0, fmt, args_for_counting) + 1;
> +
> +	va_end(args_for_counting);
> +
> +	fragment = kmalloc(sizeof(*fragment), GFP_KERNEL);
> +	if (!fragment)
> +		return -ENOMEM;
> +
> +	fragment->fragment = kmalloc(len, GFP_KERNEL);

This is confusing. See above comment.


> +	if (!fragment->fragment) {
> +		kfree(fragment);
> +		return -ENOMEM;
> +	}
> +
> +	len = vsnprintf(fragment->fragment, len, fmt, args);
> +	spin_lock_irqsave(&this->lock, flags);
> +	this->length += len;
> +	list_add_tail(&fragment->node, &this->fragments);
> +	spin_unlock_irqrestore(&this->lock, flags);
> +	return 0;
> +}
> +
> +int string_stream_add(struct string_stream *this, const char *fmt, ...)
> +{
> +	va_list args;
> +	int result;
> +
> +	va_start(args, fmt);
> +	result = string_stream_vadd(this, fmt, args);
> +	va_end(args);
> +	return result;
> +}
> +
> +void string_stream_clear(struct string_stream *this)
> +{
> +	struct string_stream_fragment *fragment, *fragment_safe;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&this->lock, flags);
> +	list_for_each_entry_safe(fragment,
> +				 fragment_safe,
> +				 &this->fragments,
> +				 node) {
> +		list_del(&fragment->node);
> +		kfree(fragment->fragment);
> +		kfree(fragment);

This is what git me down the road of checking the structure
name to begin with. :)

> +	}
> +	this->length = 0;
> +	spin_unlock_irqrestore(&this->lock, flags);
> +}
> +
> +char *string_stream_get_string(struct string_stream *this)
> +{
> +	struct string_stream_fragment *fragment;
> +	size_t buf_len = this->length + 1; /* +1 for null byte. */
> +	char *buf;
> +	unsigned long flags;
> +
> +	buf = kzalloc(buf_len, GFP_KERNEL);
> +	if (!buf)
> +		return NULL;
> +
> +	spin_lock_irqsave(&this->lock, flags);
> +	list_for_each_entry(fragment, &this->fragments, node)
> +		strlcat(buf, fragment->fragment, buf_len);
> +	spin_unlock_irqrestore(&this->lock, flags);
> +
> +	return buf;
> +}
> +
> +bool string_stream_is_empty(struct string_stream *this)
> +{
> +	bool is_empty;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&this->lock, flags);
> +	is_empty = list_empty(&this->fragments);
> +	spin_unlock_irqrestore(&this->lock, flags);
> +
> +	return is_empty;
> +}
> +
> +void destroy_string_stream(struct string_stream *stream)
> +{
> +	string_stream_clear(stream);
> +	kfree(stream);
> +}
> +
> +static void string_stream_destroy(struct kref *kref)
> +{
> +	struct string_stream *stream = container_of(kref,
> +						    struct string_stream,
> +						    refcount);
> +	destroy_string_stream(stream);
> +}
> +
> +struct string_stream *new_string_stream(void)
> +{
> +	struct string_stream *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
> +
> +	if (!stream)
> +		return NULL;
> +
> +	INIT_LIST_HEAD(&stream->fragments);
> +	spin_lock_init(&stream->lock);
> +	kref_init(&stream->refcount);
> +	return stream;
> +}
> +
> +void string_stream_get(struct string_stream *stream)
> +{
> +	kref_get(&stream->refcount);
> +}
> +
> +int string_stream_put(struct string_stream *stream)
> +{
> +	return kref_put(&stream->refcount, &string_stream_destroy);
> +}
> +
> 

thanks,
-- Shuah
Brendan Higgins May 3, 2019, 4:37 a.m. UTC | #2
On Thu, May 2, 2019 at 6:26 PM shuah <shuah@kernel.org> wrote:
>
> On 5/1/19 5:01 PM, Brendan Higgins wrote:
< snip >
> > diff --git a/kunit/Makefile b/kunit/Makefile
> > index 5efdc4dea2c08..275b565a0e81f 100644
> > --- a/kunit/Makefile
> > +++ b/kunit/Makefile
> > @@ -1 +1,2 @@
> > -obj-$(CONFIG_KUNIT) +=                       test.o
> > +obj-$(CONFIG_KUNIT) +=                       test.o \
> > +                                     string-stream.o
> > diff --git a/kunit/string-stream.c b/kunit/string-stream.c
> > new file mode 100644
> > index 0000000000000..7018194ecf2fa
> > --- /dev/null
> > +++ b/kunit/string-stream.c
> > @@ -0,0 +1,144 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * C++ stream style string builder used in KUnit for building messages.
> > + *
> > + * Copyright (C) 2019, Google LLC.
> > + * Author: Brendan Higgins <brendanhiggins@google.com>
> > + */
> > +
> > +#include <linux/list.h>
> > +#include <linux/slab.h>
> > +#include <kunit/string-stream.h>
> > +
> > +int string_stream_vadd(struct string_stream *this,
> > +                    const char *fmt,
> > +                    va_list args)
> > +{
> > +     struct string_stream_fragment *fragment;
>
> Since there is field with the same name, please use a different
> name. Using the same name for the struct which contains a field
> of the same name get very confusing and will hard to maintain
> the code.
>
> > +     int len;
> > +     va_list args_for_counting;
> > +     unsigned long flags;
> > +
> > +     /* Make a copy because `vsnprintf` could change it */
> > +     va_copy(args_for_counting, args);
> > +
> > +     /* Need space for null byte. */
> > +     len = vsnprintf(NULL, 0, fmt, args_for_counting) + 1;
> > +
> > +     va_end(args_for_counting);
> > +
> > +     fragment = kmalloc(sizeof(*fragment), GFP_KERNEL);
> > +     if (!fragment)
> > +             return -ENOMEM;
> > +
> > +     fragment->fragment = kmalloc(len, GFP_KERNEL);
>
> This is confusing. See above comment.

Good point. Will fix in the next revision.

< snip >

Thanks!

Patch
diff mbox series

diff --git a/include/kunit/string-stream.h b/include/kunit/string-stream.h
new file mode 100644
index 0000000000000..567a4629406da
--- /dev/null
+++ b/include/kunit/string-stream.h
@@ -0,0 +1,51 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * C++ stream style string builder used in KUnit for building messages.
+ *
+ * Copyright (C) 2019, Google LLC.
+ * Author: Brendan Higgins <brendanhiggins@google.com>
+ */
+
+#ifndef _KUNIT_STRING_STREAM_H
+#define _KUNIT_STRING_STREAM_H
+
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/kref.h>
+#include <stdarg.h>
+
+struct string_stream_fragment {
+	struct list_head node;
+	char *fragment;
+};
+
+struct string_stream {
+	size_t length;
+	struct list_head fragments;
+
+	/* length and fragments are protected by this lock */
+	spinlock_t lock;
+	struct kref refcount;
+};
+
+struct string_stream *new_string_stream(void);
+
+void destroy_string_stream(struct string_stream *stream);
+
+void string_stream_get(struct string_stream *stream);
+
+int string_stream_put(struct string_stream *stream);
+
+int string_stream_add(struct string_stream *this, const char *fmt, ...);
+
+int string_stream_vadd(struct string_stream *this,
+		       const char *fmt,
+		       va_list args);
+
+char *string_stream_get_string(struct string_stream *this);
+
+void string_stream_clear(struct string_stream *this);
+
+bool string_stream_is_empty(struct string_stream *this);
+
+#endif /* _KUNIT_STRING_STREAM_H */
diff --git a/kunit/Makefile b/kunit/Makefile
index 5efdc4dea2c08..275b565a0e81f 100644
--- a/kunit/Makefile
+++ b/kunit/Makefile
@@ -1 +1,2 @@ 
-obj-$(CONFIG_KUNIT) +=			test.o
+obj-$(CONFIG_KUNIT) +=			test.o \
+					string-stream.o
diff --git a/kunit/string-stream.c b/kunit/string-stream.c
new file mode 100644
index 0000000000000..7018194ecf2fa
--- /dev/null
+++ b/kunit/string-stream.c
@@ -0,0 +1,144 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * C++ stream style string builder used in KUnit for building messages.
+ *
+ * Copyright (C) 2019, Google LLC.
+ * Author: Brendan Higgins <brendanhiggins@google.com>
+ */
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <kunit/string-stream.h>
+
+int string_stream_vadd(struct string_stream *this,
+		       const char *fmt,
+		       va_list args)
+{
+	struct string_stream_fragment *fragment;
+	int len;
+	va_list args_for_counting;
+	unsigned long flags;
+
+	/* Make a copy because `vsnprintf` could change it */
+	va_copy(args_for_counting, args);
+
+	/* Need space for null byte. */
+	len = vsnprintf(NULL, 0, fmt, args_for_counting) + 1;
+
+	va_end(args_for_counting);
+
+	fragment = kmalloc(sizeof(*fragment), GFP_KERNEL);
+	if (!fragment)
+		return -ENOMEM;
+
+	fragment->fragment = kmalloc(len, GFP_KERNEL);
+	if (!fragment->fragment) {
+		kfree(fragment);
+		return -ENOMEM;
+	}
+
+	len = vsnprintf(fragment->fragment, len, fmt, args);
+	spin_lock_irqsave(&this->lock, flags);
+	this->length += len;
+	list_add_tail(&fragment->node, &this->fragments);
+	spin_unlock_irqrestore(&this->lock, flags);
+	return 0;
+}
+
+int string_stream_add(struct string_stream *this, const char *fmt, ...)
+{
+	va_list args;
+	int result;
+
+	va_start(args, fmt);
+	result = string_stream_vadd(this, fmt, args);
+	va_end(args);
+	return result;
+}
+
+void string_stream_clear(struct string_stream *this)
+{
+	struct string_stream_fragment *fragment, *fragment_safe;
+	unsigned long flags;
+
+	spin_lock_irqsave(&this->lock, flags);
+	list_for_each_entry_safe(fragment,
+				 fragment_safe,
+				 &this->fragments,
+				 node) {
+		list_del(&fragment->node);
+		kfree(fragment->fragment);
+		kfree(fragment);
+	}
+	this->length = 0;
+	spin_unlock_irqrestore(&this->lock, flags);
+}
+
+char *string_stream_get_string(struct string_stream *this)
+{
+	struct string_stream_fragment *fragment;
+	size_t buf_len = this->length + 1; /* +1 for null byte. */
+	char *buf;
+	unsigned long flags;
+
+	buf = kzalloc(buf_len, GFP_KERNEL);
+	if (!buf)
+		return NULL;
+
+	spin_lock_irqsave(&this->lock, flags);
+	list_for_each_entry(fragment, &this->fragments, node)
+		strlcat(buf, fragment->fragment, buf_len);
+	spin_unlock_irqrestore(&this->lock, flags);
+
+	return buf;
+}
+
+bool string_stream_is_empty(struct string_stream *this)
+{
+	bool is_empty;
+	unsigned long flags;
+
+	spin_lock_irqsave(&this->lock, flags);
+	is_empty = list_empty(&this->fragments);
+	spin_unlock_irqrestore(&this->lock, flags);
+
+	return is_empty;
+}
+
+void destroy_string_stream(struct string_stream *stream)
+{
+	string_stream_clear(stream);
+	kfree(stream);
+}
+
+static void string_stream_destroy(struct kref *kref)
+{
+	struct string_stream *stream = container_of(kref,
+						    struct string_stream,
+						    refcount);
+	destroy_string_stream(stream);
+}
+
+struct string_stream *new_string_stream(void)
+{
+	struct string_stream *stream = kzalloc(sizeof(*stream), GFP_KERNEL);
+
+	if (!stream)
+		return NULL;
+
+	INIT_LIST_HEAD(&stream->fragments);
+	spin_lock_init(&stream->lock);
+	kref_init(&stream->refcount);
+	return stream;
+}
+
+void string_stream_get(struct string_stream *stream)
+{
+	kref_get(&stream->refcount);
+}
+
+int string_stream_put(struct string_stream *stream)
+{
+	return kref_put(&stream->refcount, &string_stream_destroy);
+}
+