add a delta cache; saves us from reading + decompressing some deltas
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diff --git a/lib/got_repository_lib.h b/lib/got_repository_lib.h
index 2eecc5f..a8e4ced 100644
--- a/lib/got_repository_lib.h
+++ b/lib/got_repository_lib.h
@@ -14,6 +14,19 @@
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
+struct got_delta_cache_entry {
+ off_t data_offset;
+ uint8_t *delta_buf;
+ size_t delta_len;
+};
+
+#define GOT_DELTA_CACHE_SIZE 1024
+
+struct got_delta_cache {
+ char *path_packfile;
+ struct got_delta_cache_entry deltas[GOT_DELTA_CACHE_SIZE];
+};
+
#define GOT_PACKIDX_CACHE_SIZE 64
struct got_repository {
@@ -22,5 +35,8 @@ struct got_repository {
/* The pack index cache speeds up search for packed objects. */
struct got_packidx_v2_hdr *packidx_cache[GOT_PACKIDX_CACHE_SIZE];
+
+ /* The delta cache speeds up reconstruction of packed objects. */
+ struct got_delta_cache delta_cache[GOT_PACKIDX_CACHE_SIZE];
};
diff --git a/lib/pack.c b/lib/pack.c
index 52d0602..d3af74a 100644
--- a/lib/pack.c
+++ b/lib/pack.c
@@ -976,8 +976,123 @@ get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
return NULL;
}
+void
+clear_delta_cache_entry(struct got_delta_cache_entry *entry)
+{
+ entry->data_offset = 0;
+ free(entry->delta_buf);
+ entry->delta_buf = NULL;
+ entry->delta_len = 0;
+}
+
+void
+add_delta_cache_entry(struct got_delta_cache *cache, off_t data_offset,
+ uint8_t *delta_buf, size_t delta_len)
+{
+ int i;
+ struct got_delta_cache_entry *entry;
+
+ for (i = 0; i < nitems(cache->deltas); i++) {
+ entry = &cache->deltas[i];
+ if (entry->data_offset == 0)
+ break;
+ }
+
+ if (i == nitems(cache->deltas)) {
+ entry = &cache->deltas[i - 1];
+ clear_delta_cache_entry(entry);
+ memmove(&cache->deltas[1], &cache->deltas[0],
+ sizeof(cache->deltas) - sizeof(cache->deltas[0]));
+ i = 0;
+ }
+
+ entry = &cache->deltas[i];
+ entry->delta_buf = calloc(1, delta_len);
+ if (entry->delta_buf == NULL)
+ return;
+ entry->data_offset = data_offset;
+ memcpy(entry->delta_buf, delta_buf, delta_len);
+ entry->delta_len = delta_len;
+}
+
+void
+cache_delta(off_t data_offset, uint8_t *delta_buf, size_t delta_len,
+ const char *path_packfile, struct got_repository *repo)
+{
+ struct got_delta_cache *cache;
+ int i;
+
+ for (i = 0; i < nitems(repo->delta_cache); i++) {
+ cache = &repo->delta_cache[i];
+ if (cache->path_packfile == NULL)
+ break;
+ if (strcmp(cache->path_packfile, path_packfile) == 0) {
+ add_delta_cache_entry(cache, data_offset, delta_buf,
+ delta_len);
+ return;
+ }
+ }
+
+ if (i == nitems(repo->delta_cache)) {
+ int j;
+ cache = &repo->delta_cache[i - 1];
+ free(cache->path_packfile);
+ cache->path_packfile = NULL;
+ for (j = 0; j < nitems(cache->deltas); j++) {
+ struct got_delta_cache_entry *entry = &cache->deltas[j];
+ if (entry->data_offset == 0)
+ break;
+ clear_delta_cache_entry(entry);
+ }
+ memmove(&repo->delta_cache[1], &repo->delta_cache[0],
+ sizeof(repo->delta_cache) - sizeof(repo->delta_cache[0]));
+ i = 0;
+ }
+
+ cache = &repo->delta_cache[i];
+ cache->path_packfile = strdup(path_packfile);
+ if (cache->path_packfile == NULL)
+ return;
+ add_delta_cache_entry(cache, data_offset, delta_buf, delta_len);
+}
+
+void
+get_cached_delta(uint8_t **delta_buf, size_t *delta_len,
+ off_t data_offset, const char *path_packfile, struct got_repository *repo)
+{
+ struct got_delta_cache *cache;
+ struct got_delta_cache_entry *entry;
+ int i;
+
+ *delta_buf = NULL;
+ *delta_len = 0;
+
+ for (i = 0; i < nitems(repo->delta_cache); i++) {
+ cache = &repo->delta_cache[i];
+ if (cache->path_packfile == NULL)
+ return;
+ if (strcmp(cache->path_packfile, path_packfile) == 0)
+ break;
+ }
+
+ if (i == nitems(repo->delta_cache))
+ return;
+
+ for (i = 0; i < nitems(cache->deltas); i++) {
+ entry = &cache->deltas[i];
+ if (entry->data_offset == 0)
+ break;
+ if (entry->data_offset == data_offset) {
+ *delta_buf = entry->delta_buf;
+ *delta_len = entry->delta_len;
+ break;
+ }
+ }
+}
+
static const struct got_error *
-dump_delta_chain(struct got_delta_chain *deltas, FILE *outfile)
+dump_delta_chain(struct got_delta_chain *deltas, FILE *outfile,
+ const char *path_packfile, struct got_repository *repo)
{
const struct got_error *err = NULL;
struct got_delta *delta;
@@ -1014,6 +1129,7 @@ dump_delta_chain(struct got_delta_chain *deltas, FILE *outfile)
uint8_t *delta_buf = NULL;
size_t delta_len = 0;
FILE *delta_file;
+ int is_cached = 0;
delta_file = fopen(delta->path_packfile, "rb");
if (delta_file == NULL) {
@@ -1047,22 +1163,34 @@ dump_delta_chain(struct got_delta_chain *deltas, FILE *outfile)
continue;
}
- if (fseeko(delta_file, delta->data_offset, SEEK_CUR) != 0) {
+ get_cached_delta(&delta_buf, &delta_len, delta->data_offset,
+ path_packfile, repo);
+
+ if (delta_buf == NULL) {
+ if (fseeko(delta_file, delta->data_offset, SEEK_CUR)
+ != 0) {
+ fclose(delta_file);
+ err = got_error_from_errno();
+ goto done;
+ }
+
+ /* Delta streams should always fit in memory. */
+ err = got_inflate_to_mem(&delta_buf, &delta_len,
+ delta_file);
fclose(delta_file);
- err = got_error_from_errno();
- goto done;
- }
+ if (err)
+ goto done;
- /* Delta streams should always fit in memory. */
- err = got_inflate_to_mem(&delta_buf, &delta_len, delta_file);
- fclose(delta_file);
- if (err)
- goto done;
+ cache_delta(delta->data_offset, delta_buf, delta_len,
+ path_packfile, repo);
+ } else
+ is_cached = 1;
err = got_delta_apply(base_file, delta_buf, delta_len,
/* Final delta application writes to the output file. */
++n < deltas->nentries ? accum_file : outfile);
- free(delta_buf);
+ if (!is_cached)
+ free(delta_buf);
if (err)
goto done;
@@ -1113,7 +1241,8 @@ got_packfile_extract_object(FILE **f, struct got_object *obj,
err = got_inflate_to_file(&obj->size, packfile, *f);
} else
- err = dump_delta_chain(&obj->deltas, *f);
+ err = dump_delta_chain(&obj->deltas, *f, obj->path_packfile,
+ repo);
done:
if (packfile)
fclose(packfile);
diff --git a/lib/repository.c b/lib/repository.c
index 1dc1c5a..c19c013 100644
--- a/lib/repository.c
+++ b/lib/repository.c
@@ -207,6 +207,27 @@ got_repo_close(struct got_repository *repo)
break;
got_packidx_close(repo->packidx_cache[i]);
}
+
+ for (i = 0; i < nitems(repo->delta_cache); i++) {
+ struct got_delta_cache *cache = &repo->delta_cache[i];
+ int j;
+
+ if (cache->path_packfile == NULL)
+ break;
+ free(cache->path_packfile);
+ cache->path_packfile = NULL;
+
+ for (j = 0; j < nitems(cache->deltas); j++) {
+ struct got_delta_cache_entry *entry = &cache->deltas[j];
+ if (entry->data_offset == 0)
+ break;
+ entry->data_offset = 0;
+ free(entry->delta_buf);
+ entry->delta_buf = NULL;
+ entry->delta_len = 0;
+ }
+ }
+
free(repo->path);
free(repo->path_git_dir);
free(repo);