@@ -2389,6 +2389,7 @@ REFTABLE_OBJS += reftable/blocksource.o
REFTABLE_OBJS += reftable/publicbasics.o
REFTABLE_OBJS += reftable/record.o
REFTABLE_OBJS += reftable/tree.o
+REFTABLE_OBJS += reftable/writer.o
REFTABLE_OBJS += reftable/zlib-compat.o
REFTABLE_TEST_OBJS += reftable/basics_test.o
new file mode 100644
@@ -0,0 +1,147 @@
+/*
+Copyright 2020 Google LLC
+
+Use of this source code is governed by a BSD-style
+license that can be found in the LICENSE file or at
+https://developers.google.com/open-source/licenses/bsd
+*/
+
+#ifndef REFTABLE_WRITER_H
+#define REFTABLE_WRITER_H
+
+#include <stdint.h>
+
+#include "reftable-record.h"
+
+/* Writing single reftables */
+
+/* reftable_write_options sets options for writing a single reftable. */
+struct reftable_write_options {
+ /* boolean: do not pad out blocks to block size. */
+ unsigned unpadded : 1;
+
+ /* the blocksize. Should be less than 2^24. */
+ uint32_t block_size;
+
+ /* boolean: do not generate a SHA1 => ref index. */
+ unsigned skip_index_objects : 1;
+
+ /* how often to write complete keys in each block. */
+ int restart_interval;
+
+ /* 4-byte identifier ("sha1", "s256") of the hash.
+ * Defaults to SHA1 if unset
+ */
+ uint32_t hash_id;
+
+ /* boolean: do not check ref names for validity or dir/file conflicts.
+ */
+ unsigned skip_name_check : 1;
+
+ /* boolean: copy log messages exactly. If unset, check that the message
+ * is a single line, and add '\n' if missing.
+ */
+ unsigned exact_log_message : 1;
+};
+
+/* reftable_block_stats holds statistics for a single block type */
+struct reftable_block_stats {
+ /* total number of entries written */
+ int entries;
+ /* total number of key restarts */
+ int restarts;
+ /* total number of blocks */
+ int blocks;
+ /* total number of index blocks */
+ int index_blocks;
+ /* depth of the index */
+ int max_index_level;
+
+ /* offset of the first block for this type */
+ uint64_t offset;
+ /* offset of the top level index block for this type, or 0 if not
+ * present */
+ uint64_t index_offset;
+};
+
+/* stats holds overall statistics for a single reftable */
+struct reftable_stats {
+ /* total number of blocks written. */
+ int blocks;
+ /* stats for ref data */
+ struct reftable_block_stats ref_stats;
+ /* stats for the SHA1 to ref map. */
+ struct reftable_block_stats obj_stats;
+ /* stats for index blocks */
+ struct reftable_block_stats idx_stats;
+ /* stats for log blocks */
+ struct reftable_block_stats log_stats;
+
+ /* disambiguation length of shortened object IDs. */
+ int object_id_len;
+};
+
+/* reftable_new_writer creates a new writer */
+struct reftable_writer *
+reftable_new_writer(int (*writer_func)(void *, const void *, size_t),
+ void *writer_arg, struct reftable_write_options *opts);
+
+/* Set the range of update indices for the records we will add. When writing a
+ table into a stack, the min should be at least
+ reftable_stack_next_update_index(), or REFTABLE_API_ERROR is returned.
+
+ For transactional updates to a stack, typically min==max, and the
+ update_index can be obtained by inspeciting the stack. When converting an
+ existing ref database into a single reftable, this would be a range of
+ update-index timestamps.
+ */
+void reftable_writer_set_limits(struct reftable_writer *w, uint64_t min,
+ uint64_t max);
+
+/*
+ Add a reftable_ref_record. The record should have names that come after
+ already added records.
+
+ The update_index must be within the limits set by
+ reftable_writer_set_limits(), or REFTABLE_API_ERROR is returned. It is an
+ REFTABLE_API_ERROR error to write a ref record after a log record.
+*/
+int reftable_writer_add_ref(struct reftable_writer *w,
+ struct reftable_ref_record *ref);
+
+/*
+ Convenience function to add multiple reftable_ref_records; the function sorts
+ the records before adding them, reordering the records array passed in.
+*/
+int reftable_writer_add_refs(struct reftable_writer *w,
+ struct reftable_ref_record *refs, int n);
+
+/*
+ adds reftable_log_records. Log records are keyed by (refname, decreasing
+ update_index). The key for the record added must come after the already added
+ log records.
+*/
+int reftable_writer_add_log(struct reftable_writer *w,
+ struct reftable_log_record *log);
+
+/*
+ Convenience function to add multiple reftable_log_records; the function sorts
+ the records before adding them, reordering records array passed in.
+*/
+int reftable_writer_add_logs(struct reftable_writer *w,
+ struct reftable_log_record *logs, int n);
+
+/* reftable_writer_close finalizes the reftable. The writer is retained so
+ * statistics can be inspected. */
+int reftable_writer_close(struct reftable_writer *w);
+
+/* writer_stats returns the statistics on the reftable being written.
+
+ This struct becomes invalid when the writer is freed.
+ */
+const struct reftable_stats *writer_stats(struct reftable_writer *w);
+
+/* reftable_writer_free deallocates memory for the writer */
+void reftable_writer_free(struct reftable_writer *w);
+
+#endif
new file mode 100644
@@ -0,0 +1,691 @@
+/*
+Copyright 2020 Google LLC
+
+Use of this source code is governed by a BSD-style
+license that can be found in the LICENSE file or at
+https://developers.google.com/open-source/licenses/bsd
+*/
+
+#include "writer.h"
+
+#include "system.h"
+
+#include "block.h"
+#include "constants.h"
+#include "record.h"
+#include "tree.h"
+#include "reftable-error.h"
+
+/* finishes a block, and writes it to storage */
+static int writer_flush_block(struct reftable_writer *w);
+
+/* deallocates memory related to the index */
+static void writer_clear_index(struct reftable_writer *w);
+
+/* finishes writing a 'r' (refs) or 'g' (reflogs) section */
+static int writer_finish_public_section(struct reftable_writer *w);
+
+static struct reftable_block_stats *
+writer_reftable_block_stats(struct reftable_writer *w, uint8_t typ)
+{
+ switch (typ) {
+ case 'r':
+ return &w->stats.ref_stats;
+ case 'o':
+ return &w->stats.obj_stats;
+ case 'i':
+ return &w->stats.idx_stats;
+ case 'g':
+ return &w->stats.log_stats;
+ }
+ abort();
+ return NULL;
+}
+
+/* write data, queuing the padding for the next write. Returns negative for
+ * error. */
+static int padded_write(struct reftable_writer *w, uint8_t *data, size_t len,
+ int padding)
+{
+ int n = 0;
+ if (w->pending_padding > 0) {
+ uint8_t *zeroed = reftable_calloc(w->pending_padding);
+ int n = w->write(w->write_arg, zeroed, w->pending_padding);
+ if (n < 0)
+ return n;
+
+ w->pending_padding = 0;
+ reftable_free(zeroed);
+ }
+
+ w->pending_padding = padding;
+ n = w->write(w->write_arg, data, len);
+ if (n < 0)
+ return n;
+ n += padding;
+ return 0;
+}
+
+static void options_set_defaults(struct reftable_write_options *opts)
+{
+ if (opts->restart_interval == 0) {
+ opts->restart_interval = 16;
+ }
+
+ if (opts->hash_id == 0) {
+ opts->hash_id = SHA1_ID;
+ }
+ if (opts->block_size == 0) {
+ opts->block_size = DEFAULT_BLOCK_SIZE;
+ }
+}
+
+static int writer_version(struct reftable_writer *w)
+{
+ return (w->opts.hash_id == 0 || w->opts.hash_id == SHA1_ID) ? 1 : 2;
+}
+
+static int writer_write_header(struct reftable_writer *w, uint8_t *dest)
+{
+ memcpy((char *)dest, "REFT", 4);
+
+ dest[4] = writer_version(w);
+
+ put_be24(dest + 5, w->opts.block_size);
+ put_be64(dest + 8, w->min_update_index);
+ put_be64(dest + 16, w->max_update_index);
+ if (writer_version(w) == 2) {
+ put_be32(dest + 24, w->opts.hash_id);
+ }
+ return header_size(writer_version(w));
+}
+
+static void writer_reinit_block_writer(struct reftable_writer *w, uint8_t typ)
+{
+ int block_start = 0;
+ if (w->next == 0) {
+ block_start = header_size(writer_version(w));
+ }
+
+ strbuf_release(&w->last_key);
+ block_writer_init(&w->block_writer_data, typ, w->block,
+ w->opts.block_size, block_start,
+ hash_size(w->opts.hash_id));
+ w->block_writer = &w->block_writer_data;
+ w->block_writer->restart_interval = w->opts.restart_interval;
+}
+
+static struct strbuf reftable_empty_strbuf = STRBUF_INIT;
+
+struct reftable_writer *
+reftable_new_writer(int (*writer_func)(void *, const void *, size_t),
+ void *writer_arg, struct reftable_write_options *opts)
+{
+ struct reftable_writer *wp =
+ reftable_calloc(sizeof(struct reftable_writer));
+ strbuf_init(&wp->block_writer_data.last_key, 0);
+ options_set_defaults(opts);
+ if (opts->block_size >= (1 << 24)) {
+ /* TODO - error return? */
+ abort();
+ }
+ wp->last_key = reftable_empty_strbuf;
+ wp->block = reftable_calloc(opts->block_size);
+ wp->write = writer_func;
+ wp->write_arg = writer_arg;
+ wp->opts = *opts;
+ writer_reinit_block_writer(wp, BLOCK_TYPE_REF);
+
+ return wp;
+}
+
+void reftable_writer_set_limits(struct reftable_writer *w, uint64_t min,
+ uint64_t max)
+{
+ w->min_update_index = min;
+ w->max_update_index = max;
+}
+
+void reftable_writer_free(struct reftable_writer *w)
+{
+ reftable_free(w->block);
+ reftable_free(w);
+}
+
+struct obj_index_tree_node {
+ struct strbuf hash;
+ uint64_t *offsets;
+ size_t offset_len;
+ size_t offset_cap;
+};
+
+#define OBJ_INDEX_TREE_NODE_INIT \
+ { \
+ .hash = STRBUF_INIT \
+ }
+
+static int obj_index_tree_node_compare(const void *a, const void *b)
+{
+ return strbuf_cmp(&((const struct obj_index_tree_node *)a)->hash,
+ &((const struct obj_index_tree_node *)b)->hash);
+}
+
+static void writer_index_hash(struct reftable_writer *w, struct strbuf *hash)
+{
+ uint64_t off = w->next;
+
+ struct obj_index_tree_node want = { .hash = *hash };
+
+ struct tree_node *node = tree_search(&want, &w->obj_index_tree,
+ &obj_index_tree_node_compare, 0);
+ struct obj_index_tree_node *key = NULL;
+ if (node == NULL) {
+ struct obj_index_tree_node empty = OBJ_INDEX_TREE_NODE_INIT;
+ key = reftable_malloc(sizeof(struct obj_index_tree_node));
+ *key = empty;
+
+ strbuf_reset(&key->hash);
+ strbuf_addbuf(&key->hash, hash);
+ tree_search((void *)key, &w->obj_index_tree,
+ &obj_index_tree_node_compare, 1);
+ } else {
+ key = node->key;
+ }
+
+ if (key->offset_len > 0 && key->offsets[key->offset_len - 1] == off) {
+ return;
+ }
+
+ if (key->offset_len == key->offset_cap) {
+ key->offset_cap = 2 * key->offset_cap + 1;
+ key->offsets = reftable_realloc(
+ key->offsets, sizeof(uint64_t) * key->offset_cap);
+ }
+
+ key->offsets[key->offset_len++] = off;
+}
+
+static int writer_add_record(struct reftable_writer *w,
+ struct reftable_record *rec)
+{
+ int result = -1;
+ struct strbuf key = STRBUF_INIT;
+ int err = 0;
+ reftable_record_key(rec, &key);
+ if (strbuf_cmp(&w->last_key, &key) >= 0)
+ goto done;
+
+ strbuf_reset(&w->last_key);
+ strbuf_addbuf(&w->last_key, &key);
+ if (w->block_writer == NULL) {
+ writer_reinit_block_writer(w, reftable_record_type(rec));
+ }
+
+ assert(block_writer_type(w->block_writer) == reftable_record_type(rec));
+
+ if (block_writer_add(w->block_writer, rec) == 0) {
+ result = 0;
+ goto done;
+ }
+
+ err = writer_flush_block(w);
+ if (err < 0) {
+ result = err;
+ goto done;
+ }
+
+ writer_reinit_block_writer(w, reftable_record_type(rec));
+ err = block_writer_add(w->block_writer, rec);
+ if (err < 0) {
+ result = err;
+ goto done;
+ }
+
+ result = 0;
+done:
+ strbuf_release(&key);
+ return result;
+}
+
+int reftable_writer_add_ref(struct reftable_writer *w,
+ struct reftable_ref_record *ref)
+{
+ struct reftable_record rec = { NULL };
+ struct reftable_ref_record copy = *ref;
+ int err = 0;
+
+ if (ref->refname == NULL)
+ return REFTABLE_API_ERROR;
+ if (ref->update_index < w->min_update_index ||
+ ref->update_index > w->max_update_index)
+ return REFTABLE_API_ERROR;
+
+ reftable_record_from_ref(&rec, ©);
+ copy.update_index -= w->min_update_index;
+
+ err = writer_add_record(w, &rec);
+ if (err < 0)
+ return err;
+
+ if (!w->opts.skip_index_objects &&
+ reftable_ref_record_val1(ref) != NULL) {
+ struct strbuf h = STRBUF_INIT;
+ strbuf_add(&h, (char *)reftable_ref_record_val1(ref),
+ hash_size(w->opts.hash_id));
+ writer_index_hash(w, &h);
+ strbuf_release(&h);
+ }
+
+ if (!w->opts.skip_index_objects &&
+ reftable_ref_record_val2(ref) != NULL) {
+ struct strbuf h = STRBUF_INIT;
+ strbuf_add(&h, reftable_ref_record_val2(ref),
+ hash_size(w->opts.hash_id));
+ writer_index_hash(w, &h);
+ strbuf_release(&h);
+ }
+ return 0;
+}
+
+int reftable_writer_add_refs(struct reftable_writer *w,
+ struct reftable_ref_record *refs, int n)
+{
+ int err = 0;
+ int i = 0;
+ QSORT(refs, n, reftable_ref_record_compare_name);
+ for (i = 0; err == 0 && i < n; i++) {
+ err = reftable_writer_add_ref(w, &refs[i]);
+ }
+ return err;
+}
+
+static int reftable_writer_add_log_verbatim(struct reftable_writer *w,
+ struct reftable_log_record *log)
+{
+ struct reftable_record rec = { NULL };
+ if (w->block_writer != NULL &&
+ block_writer_type(w->block_writer) == BLOCK_TYPE_REF) {
+ int err = writer_finish_public_section(w);
+ if (err < 0)
+ return err;
+ }
+
+ w->next -= w->pending_padding;
+ w->pending_padding = 0;
+
+ reftable_record_from_log(&rec, log);
+ return writer_add_record(w, &rec);
+}
+
+int reftable_writer_add_log(struct reftable_writer *w,
+ struct reftable_log_record *log)
+{
+ char *input_log_message = NULL;
+ struct strbuf cleaned_message = STRBUF_INIT;
+ int err = 0;
+
+ if (log->value_type == REFTABLE_LOG_DELETION)
+ return reftable_writer_add_log_verbatim(w, log);
+
+ if (log->refname == NULL)
+ return REFTABLE_API_ERROR;
+
+ input_log_message = log->update.message;
+ if (!w->opts.exact_log_message && log->update.message != NULL) {
+ strbuf_addstr(&cleaned_message, log->update.message);
+ while (cleaned_message.len &&
+ cleaned_message.buf[cleaned_message.len - 1] == '\n')
+ strbuf_setlen(&cleaned_message,
+ cleaned_message.len - 1);
+ if (strchr(cleaned_message.buf, '\n')) {
+ // multiple lines not allowed.
+ err = REFTABLE_API_ERROR;
+ goto done;
+ }
+ strbuf_addstr(&cleaned_message, "\n");
+ log->update.message = cleaned_message.buf;
+ }
+
+ err = reftable_writer_add_log_verbatim(w, log);
+ log->update.message = input_log_message;
+done:
+ strbuf_release(&cleaned_message);
+ return err;
+}
+
+int reftable_writer_add_logs(struct reftable_writer *w,
+ struct reftable_log_record *logs, int n)
+{
+ int err = 0;
+ int i = 0;
+ QSORT(logs, n, reftable_log_record_compare_key);
+
+ for (i = 0; err == 0 && i < n; i++) {
+ err = reftable_writer_add_log(w, &logs[i]);
+ }
+ return err;
+}
+
+static int writer_finish_section(struct reftable_writer *w)
+{
+ uint8_t typ = block_writer_type(w->block_writer);
+ uint64_t index_start = 0;
+ int max_level = 0;
+ int threshold = w->opts.unpadded ? 1 : 3;
+ int before_blocks = w->stats.idx_stats.blocks;
+ int err = writer_flush_block(w);
+ int i = 0;
+ struct reftable_block_stats *bstats = NULL;
+ if (err < 0)
+ return err;
+
+ while (w->index_len > threshold) {
+ struct reftable_index_record *idx = NULL;
+ int idx_len = 0;
+
+ max_level++;
+ index_start = w->next;
+ writer_reinit_block_writer(w, BLOCK_TYPE_INDEX);
+
+ idx = w->index;
+ idx_len = w->index_len;
+
+ w->index = NULL;
+ w->index_len = 0;
+ w->index_cap = 0;
+ for (i = 0; i < idx_len; i++) {
+ struct reftable_record rec = { NULL };
+ reftable_record_from_index(&rec, idx + i);
+ if (block_writer_add(w->block_writer, &rec) == 0) {
+ continue;
+ }
+
+ err = writer_flush_block(w);
+ if (err < 0)
+ return err;
+
+ writer_reinit_block_writer(w, BLOCK_TYPE_INDEX);
+
+ err = block_writer_add(w->block_writer, &rec);
+ if (err != 0) {
+ /* write into fresh block should always succeed
+ */
+ abort();
+ }
+ }
+ for (i = 0; i < idx_len; i++) {
+ strbuf_release(&idx[i].last_key);
+ }
+ reftable_free(idx);
+ }
+
+ writer_clear_index(w);
+
+ err = writer_flush_block(w);
+ if (err < 0)
+ return err;
+
+ bstats = writer_reftable_block_stats(w, typ);
+ bstats->index_blocks = w->stats.idx_stats.blocks - before_blocks;
+ bstats->index_offset = index_start;
+ bstats->max_index_level = max_level;
+
+ /* Reinit lastKey, as the next section can start with any key. */
+ w->last_key.len = 0;
+
+ return 0;
+}
+
+struct common_prefix_arg {
+ struct strbuf *last;
+ int max;
+};
+
+static void update_common(void *void_arg, void *key)
+{
+ struct common_prefix_arg *arg = (struct common_prefix_arg *)void_arg;
+ struct obj_index_tree_node *entry = (struct obj_index_tree_node *)key;
+ if (arg->last != NULL) {
+ int n = common_prefix_size(&entry->hash, arg->last);
+ if (n > arg->max) {
+ arg->max = n;
+ }
+ }
+ arg->last = &entry->hash;
+}
+
+struct write_record_arg {
+ struct reftable_writer *w;
+ int err;
+};
+
+static void write_object_record(void *void_arg, void *key)
+{
+ struct write_record_arg *arg = (struct write_record_arg *)void_arg;
+ struct obj_index_tree_node *entry = (struct obj_index_tree_node *)key;
+ struct reftable_obj_record obj_rec = {
+ .hash_prefix = (uint8_t *)entry->hash.buf,
+ .hash_prefix_len = arg->w->stats.object_id_len,
+ .offsets = entry->offsets,
+ .offset_len = entry->offset_len,
+ };
+ struct reftable_record rec = { NULL };
+ if (arg->err < 0)
+ goto done;
+
+ reftable_record_from_obj(&rec, &obj_rec);
+ arg->err = block_writer_add(arg->w->block_writer, &rec);
+ if (arg->err == 0)
+ goto done;
+
+ arg->err = writer_flush_block(arg->w);
+ if (arg->err < 0)
+ goto done;
+
+ writer_reinit_block_writer(arg->w, BLOCK_TYPE_OBJ);
+ arg->err = block_writer_add(arg->w->block_writer, &rec);
+ if (arg->err == 0)
+ goto done;
+ obj_rec.offset_len = 0;
+ arg->err = block_writer_add(arg->w->block_writer, &rec);
+
+ /* Should be able to write into a fresh block. */
+ assert(arg->err == 0);
+
+done:;
+}
+
+static void object_record_free(void *void_arg, void *key)
+{
+ struct obj_index_tree_node *entry = (struct obj_index_tree_node *)key;
+
+ FREE_AND_NULL(entry->offsets);
+ strbuf_release(&entry->hash);
+ reftable_free(entry);
+}
+
+static int writer_dump_object_index(struct reftable_writer *w)
+{
+ struct write_record_arg closure = { .w = w };
+ struct common_prefix_arg common = { NULL };
+ if (w->obj_index_tree != NULL) {
+ infix_walk(w->obj_index_tree, &update_common, &common);
+ }
+ w->stats.object_id_len = common.max + 1;
+
+ writer_reinit_block_writer(w, BLOCK_TYPE_OBJ);
+
+ if (w->obj_index_tree != NULL) {
+ infix_walk(w->obj_index_tree, &write_object_record, &closure);
+ }
+
+ if (closure.err < 0)
+ return closure.err;
+ return writer_finish_section(w);
+}
+
+static int writer_finish_public_section(struct reftable_writer *w)
+{
+ uint8_t typ = 0;
+ int err = 0;
+
+ if (w->block_writer == NULL)
+ return 0;
+
+ typ = block_writer_type(w->block_writer);
+ err = writer_finish_section(w);
+ if (err < 0)
+ return err;
+ if (typ == BLOCK_TYPE_REF && !w->opts.skip_index_objects &&
+ w->stats.ref_stats.index_blocks > 0) {
+ err = writer_dump_object_index(w);
+ if (err < 0)
+ return err;
+ }
+
+ if (w->obj_index_tree != NULL) {
+ infix_walk(w->obj_index_tree, &object_record_free, NULL);
+ tree_free(w->obj_index_tree);
+ w->obj_index_tree = NULL;
+ }
+
+ w->block_writer = NULL;
+ return 0;
+}
+
+int reftable_writer_close(struct reftable_writer *w)
+{
+ uint8_t footer[72];
+ uint8_t *p = footer;
+ int err = writer_finish_public_section(w);
+ int empty_table = w->next == 0;
+ if (err != 0)
+ goto done;
+ w->pending_padding = 0;
+ if (empty_table) {
+ /* Empty tables need a header anyway. */
+ uint8_t header[28];
+ int n = writer_write_header(w, header);
+ err = padded_write(w, header, n, 0);
+ if (err < 0)
+ goto done;
+ }
+
+ p += writer_write_header(w, footer);
+ put_be64(p, w->stats.ref_stats.index_offset);
+ p += 8;
+ put_be64(p, (w->stats.obj_stats.offset) << 5 | w->stats.object_id_len);
+ p += 8;
+ put_be64(p, w->stats.obj_stats.index_offset);
+ p += 8;
+
+ put_be64(p, w->stats.log_stats.offset);
+ p += 8;
+ put_be64(p, w->stats.log_stats.index_offset);
+ p += 8;
+
+ put_be32(p, crc32(0, footer, p - footer));
+ p += 4;
+
+ err = padded_write(w, footer, footer_size(writer_version(w)), 0);
+ if (err < 0)
+ goto done;
+
+ if (empty_table) {
+ err = REFTABLE_EMPTY_TABLE_ERROR;
+ goto done;
+ }
+
+done:
+ /* free up memory. */
+ block_writer_release(&w->block_writer_data);
+ writer_clear_index(w);
+ strbuf_release(&w->last_key);
+ return err;
+}
+
+static void writer_clear_index(struct reftable_writer *w)
+{
+ int i = 0;
+ for (i = 0; i < w->index_len; i++) {
+ strbuf_release(&w->index[i].last_key);
+ }
+
+ FREE_AND_NULL(w->index);
+ w->index_len = 0;
+ w->index_cap = 0;
+}
+
+static const int debug = 0;
+
+static int writer_flush_nonempty_block(struct reftable_writer *w)
+{
+ uint8_t typ = block_writer_type(w->block_writer);
+ struct reftable_block_stats *bstats =
+ writer_reftable_block_stats(w, typ);
+ uint64_t block_typ_off = (bstats->blocks == 0) ? w->next : 0;
+ int raw_bytes = block_writer_finish(w->block_writer);
+ int padding = 0;
+ int err = 0;
+ struct reftable_index_record ir = { .last_key = STRBUF_INIT };
+ if (raw_bytes < 0)
+ return raw_bytes;
+
+ if (!w->opts.unpadded && typ != BLOCK_TYPE_LOG) {
+ padding = w->opts.block_size - raw_bytes;
+ }
+
+ if (block_typ_off > 0) {
+ bstats->offset = block_typ_off;
+ }
+
+ bstats->entries += w->block_writer->entries;
+ bstats->restarts += w->block_writer->restart_len;
+ bstats->blocks++;
+ w->stats.blocks++;
+
+ if (debug) {
+ fprintf(stderr, "block %c off %" PRIu64 " sz %d (%d)\n", typ,
+ w->next, raw_bytes,
+ get_be24(w->block + w->block_writer->header_off + 1));
+ }
+
+ if (w->next == 0) {
+ writer_write_header(w, w->block);
+ }
+
+ err = padded_write(w, w->block, raw_bytes, padding);
+ if (err < 0)
+ return err;
+
+ if (w->index_cap == w->index_len) {
+ w->index_cap = 2 * w->index_cap + 1;
+ w->index = reftable_realloc(
+ w->index,
+ sizeof(struct reftable_index_record) * w->index_cap);
+ }
+
+ ir.offset = w->next;
+ strbuf_reset(&ir.last_key);
+ strbuf_addbuf(&ir.last_key, &w->block_writer->last_key);
+ w->index[w->index_len] = ir;
+
+ w->index_len++;
+ w->next += padding + raw_bytes;
+ w->block_writer = NULL;
+ return 0;
+}
+
+static int writer_flush_block(struct reftable_writer *w)
+{
+ if (w->block_writer == NULL)
+ return 0;
+ if (w->block_writer->entries == 0)
+ return 0;
+ return writer_flush_nonempty_block(w);
+}
+
+const struct reftable_stats *writer_stats(struct reftable_writer *w)
+{
+ return &w->stats;
+}
new file mode 100644
@@ -0,0 +1,50 @@
+/*
+Copyright 2020 Google LLC
+
+Use of this source code is governed by a BSD-style
+license that can be found in the LICENSE file or at
+https://developers.google.com/open-source/licenses/bsd
+*/
+
+#ifndef WRITER_H
+#define WRITER_H
+
+#include "basics.h"
+#include "block.h"
+#include "tree.h"
+#include "reftable-writer.h"
+
+struct reftable_writer {
+ int (*write)(void *, const void *, size_t);
+ void *write_arg;
+ int pending_padding;
+ struct strbuf last_key;
+
+ /* offset of next block to write. */
+ uint64_t next;
+ uint64_t min_update_index, max_update_index;
+ struct reftable_write_options opts;
+
+ /* memory buffer for writing */
+ uint8_t *block;
+
+ /* writer for the current section. NULL or points to
+ * block_writer_data */
+ struct block_writer *block_writer;
+
+ struct block_writer block_writer_data;
+
+ /* pending index records for the current section */
+ struct reftable_index_record *index;
+ size_t index_len;
+ size_t index_cap;
+
+ /*
+ * tree for use with tsearch; used to populate the 'o' inverse OID
+ * map */
+ struct tree_node *obj_index_tree;
+
+ struct reftable_stats stats;
+};
+
+#endif