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Diffstat (limited to 'src/libgit2/odb_pack.c')
| -rw-r--r-- | src/libgit2/odb_pack.c | 921 |
1 files changed, 921 insertions, 0 deletions
diff --git a/src/libgit2/odb_pack.c b/src/libgit2/odb_pack.c new file mode 100644 index 000000000..818cc6125 --- /dev/null +++ b/src/libgit2/odb_pack.c @@ -0,0 +1,921 @@ +/* + * Copyright (C) the libgit2 contributors. All rights reserved. + * + * This file is part of libgit2, distributed under the GNU GPL v2 with + * a Linking Exception. For full terms see the included COPYING file. + */ + +#include "common.h" + +#include <zlib.h> +#include "git2/repository.h" +#include "git2/indexer.h" +#include "git2/sys/odb_backend.h" +#include "delta.h" +#include "futils.h" +#include "hash.h" +#include "midx.h" +#include "mwindow.h" +#include "odb.h" +#include "pack.h" + +#include "git2/odb_backend.h" + +/* re-freshen pack files no more than every 2 seconds */ +#define FRESHEN_FREQUENCY 2 + +struct pack_backend { + git_odb_backend parent; + git_midx_file *midx; + git_vector midx_packs; + git_vector packs; + struct git_pack_file *last_found; + char *pack_folder; +}; + +struct pack_writepack { + struct git_odb_writepack parent; + git_indexer *indexer; +}; + +/** + * The wonderful tale of a Packed Object lookup query + * =================================================== + * A riveting and epic story of epicness and ASCII + * art, presented by yours truly, + * Sir Vicent of Marti + * + * + * Chapter 1: Once upon a time... + * Initialization of the Pack Backend + * -------------------------------------------------- + * + * # git_odb_backend_pack + * | Creates the pack backend structure, initializes the + * | callback pointers to our default read() and exist() methods, + * | and tries to find the `pack` folder, if it exists. ODBs without a `pack` + * | folder are ignored altogether. If there is a `pack` folder, it tries to + * | preload all the known packfiles in the ODB. + * | + * |-# pack_backend__refresh + * | The `multi-pack-index` is loaded if it exists and is valid. + * | Then we run a `dirent` callback through every file in the pack folder, + * | even those present in `multi-pack-index`. The unindexed packfiles are + * | then sorted according to a sorting callback. + * | + * |-# refresh_multi_pack_index + * | Detect the presence of the `multi-pack-index` file. If it needs to be + * | refreshed, frees the old copy and tries to load the new one, together + * | with all the packfiles it indexes. If the process fails, fall back to + * | the old behavior, as if the `multi-pack-index` file was not there. + * | + * |-# packfile_load__cb + * | | This callback is called from `dirent` with every single file + * | | inside the pack folder. We find the packs by actually locating + * | | their index (ends in ".idx"). From that index, we verify that + * | | the corresponding packfile exists and is valid, and if so, we + * | | add it to the pack list. + * | | + * | # git_mwindow_get_pack + * | Make sure that there's a packfile to back this index, and store + * | some very basic information regarding the packfile itself, + * | such as the full path, the size, and the modification time. + * | We don't actually open the packfile to check for internal consistency. + * | + * |-# packfile_sort__cb + * Sort all the preloaded packs according to some specific criteria: + * we prioritize the "newer" packs because it's more likely they + * contain the objects we are looking for, and we prioritize local + * packs over remote ones. + * + * + * + * Chapter 2: To be, or not to be... + * A standard packed `exist` query for an OID + * -------------------------------------------------- + * + * # pack_backend__exists / pack_backend__exists_prefix + * | Check if the given SHA1 oid (or a SHA1 oid prefix) exists in any of the + * | packs that have been loaded for our ODB. + * | + * |-# pack_entry_find / pack_entry_find_prefix + * | If there is a multi-pack-index present, search the SHA1 oid in that + * | index first. If it is not found there, iterate through all the unindexed + * | packs that have been preloaded (starting by the pack where the latest + * | object was found) to try to find the OID in one of them. + * | + * |-# git_midx_entry_find + * | Search for the SHA1 oid in the multi-pack-index. See + * | <https://github.com/git/git/blob/master/Documentation/technical/pack-format.txt> + * | for specifics on the multi-pack-index format and how do we find + * | entries in it. + * | + * |-# git_pack_entry_find + * | Check the index of an individual unindexed pack to see if the SHA1 + * | OID can be found. If we can find the offset to that SHA1 inside of the + * | index, that means the object is contained inside of the packfile and + * | we can stop searching. Before returning, we verify that the + * | packfile behind the index we are searching still exists on disk. + * | + * |-# pack_entry_find_offset + * | Mmap the actual index file to disk if it hasn't been opened + * | yet, and run a binary search through it to find the OID. + * | See <https://github.com/git/git/blob/master/Documentation/technical/pack-format.txt> + * | for specifics on the Packfile Index format and how do we find + * | entries in it. + * | + * |-# pack_index_open + * | Guess the name of the index based on the full path to the + * | packfile, open it and verify its contents. Only if the index + * | has not been opened already. + * | + * |-# pack_index_check + * Mmap the index file and do a quick run through the header + * to guess the index version (right now we support v1 and v2), + * and to verify that the size of the index makes sense. + * + * + * + * Chapter 3: The neverending story... + * A standard packed `lookup` query for an OID + * -------------------------------------------------- + * + * # pack_backend__read / pack_backend__read_prefix + * | Check if the given SHA1 oid (or a SHA1 oid prefix) exists in any of the + * | packs that have been loaded for our ODB. If it does, open the packfile and + * | read from it. + * | + * |-# git_packfile_unpack + * Armed with a packfile and the offset within it, we can finally unpack + * the object pointed at by the SHA1 oid. This involves mmapping part of + * the `.pack` file, and uncompressing the object within it (if it is + * stored in the undelfitied representation), or finding a base object and + * applying some deltas to its uncompressed representation (if it is stored + * in the deltified representation). See + * <https://github.com/git/git/blob/master/Documentation/technical/pack-format.txt> + * for specifics on the Packfile format and how do we read from it. + * + */ + + +/*********************************************************** + * + * FORWARD DECLARATIONS + * + ***********************************************************/ + +static int packfile_sort__cb(const void *a_, const void *b_); + +static int packfile_load__cb(void *_data, git_str *path); + +static int packfile_byname_search_cmp(const void *path, const void *pack_entry); + +static int pack_entry_find(struct git_pack_entry *e, + struct pack_backend *backend, const git_oid *oid); + +/* Can find the offset of an object given + * a prefix of an identifier. + * Sets GIT_EAMBIGUOUS if short oid is ambiguous. + * This method assumes that len is between + * GIT_OID_MINPREFIXLEN and GIT_OID_HEXSZ. + */ +static int pack_entry_find_prefix( + struct git_pack_entry *e, + struct pack_backend *backend, + const git_oid *short_oid, + size_t len); + + + +/*********************************************************** + * + * PACK WINDOW MANAGEMENT + * + ***********************************************************/ + +static int packfile_byname_search_cmp(const void *path_, const void *p_) +{ + const git_str *path = (const git_str *)path_; + const struct git_pack_file *p = (const struct git_pack_file *)p_; + + return strncmp(p->pack_name, git_str_cstr(path), git_str_len(path)); +} + +static int packfile_sort__cb(const void *a_, const void *b_) +{ + const struct git_pack_file *a = a_; + const struct git_pack_file *b = b_; + int st; + + /* + * Local packs tend to contain objects specific to our + * variant of the project than remote ones. In addition, + * remote ones could be on a network mounted filesystem. + * Favor local ones for these reasons. + */ + st = a->pack_local - b->pack_local; + if (st) + return -st; + + /* + * Younger packs tend to contain more recent objects, + * and more recent objects tend to get accessed more + * often. + */ + if (a->mtime < b->mtime) + return 1; + else if (a->mtime == b->mtime) + return 0; + + return -1; +} + + +static int packfile_load__cb(void *data, git_str *path) +{ + struct pack_backend *backend = data; + struct git_pack_file *pack; + const char *path_str = git_str_cstr(path); + git_str index_prefix = GIT_STR_INIT; + size_t cmp_len = git_str_len(path); + int error; + + if (cmp_len <= strlen(".idx") || git__suffixcmp(path_str, ".idx") != 0) + return 0; /* not an index */ + + cmp_len -= strlen(".idx"); + git_str_attach_notowned(&index_prefix, path_str, cmp_len); + + if (git_vector_search2(NULL, &backend->midx_packs, packfile_byname_search_cmp, &index_prefix) == 0) + return 0; + if (git_vector_search2(NULL, &backend->packs, packfile_byname_search_cmp, &index_prefix) == 0) + return 0; + + error = git_mwindow_get_pack(&pack, path->ptr); + + /* ignore missing .pack file as git does */ + if (error == GIT_ENOTFOUND) { + git_error_clear(); + return 0; + } + + if (!error) + error = git_vector_insert(&backend->packs, pack); + + return error; + +} + +static int pack_entry_find(struct git_pack_entry *e, struct pack_backend *backend, const git_oid *oid) +{ + struct git_pack_file *last_found = backend->last_found, *p; + git_midx_entry midx_entry; + size_t i; + + if (backend->midx && + git_midx_entry_find(&midx_entry, backend->midx, oid, GIT_OID_HEXSZ) == 0 && + midx_entry.pack_index < git_vector_length(&backend->midx_packs)) { + e->offset = midx_entry.offset; + git_oid_cpy(&e->sha1, &midx_entry.sha1); + e->p = git_vector_get(&backend->midx_packs, midx_entry.pack_index); + return 0; + } + + if (last_found && + git_pack_entry_find(e, last_found, oid, GIT_OID_HEXSZ) == 0) + return 0; + + git_vector_foreach(&backend->packs, i, p) { + if (p == last_found) + continue; + + if (git_pack_entry_find(e, p, oid, GIT_OID_HEXSZ) == 0) { + backend->last_found = p; + return 0; + } + } + + return git_odb__error_notfound( + "failed to find pack entry", oid, GIT_OID_HEXSZ); +} + +static int pack_entry_find_prefix( + struct git_pack_entry *e, + struct pack_backend *backend, + const git_oid *short_oid, + size_t len) +{ + int error; + size_t i; + git_oid found_full_oid = {{0}}; + bool found = false; + struct git_pack_file *last_found = backend->last_found, *p; + git_midx_entry midx_entry; + + if (backend->midx) { + error = git_midx_entry_find(&midx_entry, backend->midx, short_oid, len); + if (error == GIT_EAMBIGUOUS) + return error; + if (!error && midx_entry.pack_index < git_vector_length(&backend->midx_packs)) { + e->offset = midx_entry.offset; + git_oid_cpy(&e->sha1, &midx_entry.sha1); + e->p = git_vector_get(&backend->midx_packs, midx_entry.pack_index); + git_oid_cpy(&found_full_oid, &e->sha1); + found = true; + } + } + + if (last_found) { + error = git_pack_entry_find(e, last_found, short_oid, len); + if (error == GIT_EAMBIGUOUS) + return error; + if (!error) { + if (found && git_oid_cmp(&e->sha1, &found_full_oid)) + return git_odb__error_ambiguous("found multiple pack entries"); + git_oid_cpy(&found_full_oid, &e->sha1); + found = true; + } + } + + git_vector_foreach(&backend->packs, i, p) { + if (p == last_found) + continue; + + error = git_pack_entry_find(e, p, short_oid, len); + if (error == GIT_EAMBIGUOUS) + return error; + if (!error) { + if (found && git_oid_cmp(&e->sha1, &found_full_oid)) + return git_odb__error_ambiguous("found multiple pack entries"); + git_oid_cpy(&found_full_oid, &e->sha1); + found = true; + backend->last_found = p; + } + } + + if (!found) + return git_odb__error_notfound("no matching pack entry for prefix", + short_oid, len); + else + return 0; +} + +/*********************************************************** + * + * MULTI-PACK-INDEX SUPPORT + * + * Functions needed to support the multi-pack-index. + * + ***********************************************************/ + +/* + * Remove the multi-pack-index, and move all midx_packs to packs. + */ +static int remove_multi_pack_index(struct pack_backend *backend) +{ + size_t i, j = git_vector_length(&backend->packs); + struct pack_backend *p; + int error = git_vector_size_hint( + &backend->packs, + j + git_vector_length(&backend->midx_packs)); + if (error < 0) + return error; + + git_vector_foreach(&backend->midx_packs, i, p) + git_vector_set(NULL, &backend->packs, j++, p); + git_vector_clear(&backend->midx_packs); + + git_midx_free(backend->midx); + backend->midx = NULL; + + return 0; +} + +/* + * Loads a single .pack file referred to by the multi-pack-index. These must + * match the order in which they are declared in the multi-pack-index file, + * since these files are referred to by their index. + */ +static int process_multi_pack_index_pack( + struct pack_backend *backend, + size_t i, + const char *packfile_name) +{ + int error; + struct git_pack_file *pack; + size_t found_position; + git_str pack_path = GIT_STR_INIT, index_prefix = GIT_STR_INIT; + + error = git_str_joinpath(&pack_path, backend->pack_folder, packfile_name); + if (error < 0) + return error; + + /* This is ensured by midx_parse_packfile_name() */ + if (git_str_len(&pack_path) <= strlen(".idx") || git__suffixcmp(git_str_cstr(&pack_path), ".idx") != 0) + return git_odb__error_notfound("midx file contained a non-index", NULL, 0); + + git_str_attach_notowned(&index_prefix, git_str_cstr(&pack_path), git_str_len(&pack_path) - strlen(".idx")); + + if (git_vector_search2(&found_position, &backend->packs, packfile_byname_search_cmp, &index_prefix) == 0) { + /* Pack was found in the packs list. Moving it to the midx_packs list. */ + git_str_dispose(&pack_path); + git_vector_set(NULL, &backend->midx_packs, i, git_vector_get(&backend->packs, found_position)); + git_vector_remove(&backend->packs, found_position); + return 0; + } + + /* Pack was not found. Allocate a new one. */ + error = git_mwindow_get_pack(&pack, git_str_cstr(&pack_path)); + git_str_dispose(&pack_path); + if (error < 0) + return error; + + git_vector_set(NULL, &backend->midx_packs, i, pack); + return 0; +} + +/* + * Reads the multi-pack-index. If this fails for whatever reason, the + * multi-pack-index object is freed, and all the packfiles that are related to + * it are moved to the unindexed packfiles vector. + */ +static int refresh_multi_pack_index(struct pack_backend *backend) +{ + int error; + git_str midx_path = GIT_STR_INIT; + const char *packfile_name; + size_t i; + + error = git_str_joinpath(&midx_path, backend->pack_folder, "multi-pack-index"); + if (error < 0) + return error; + + /* + * Check whether the multi-pack-index has changed. If it has, close any + * old multi-pack-index and move all the packfiles to the unindexed + * packs. This is done to prevent losing any open packfiles in case + * refreshing the new multi-pack-index fails, or the file is deleted. + */ + if (backend->midx) { + if (!git_midx_needs_refresh(backend->midx, git_str_cstr(&midx_path))) { + git_str_dispose(&midx_path); + return 0; + } + error = remove_multi_pack_index(backend); + if (error < 0) { + git_str_dispose(&midx_path); + return error; + } + } + + error = git_midx_open(&backend->midx, git_str_cstr(&midx_path)); + git_str_dispose(&midx_path); + if (error < 0) + return error; + + git_vector_resize_to(&backend->midx_packs, git_vector_length(&backend->midx->packfile_names)); + + git_vector_foreach(&backend->midx->packfile_names, i, packfile_name) { + error = process_multi_pack_index_pack(backend, i, packfile_name); + if (error < 0) { + /* + * Something failed during reading multi-pack-index. + * Restore the state of backend as if the + * multi-pack-index was never there, and move all + * packfiles that have been processed so far to the + * unindexed packs. + */ + git_vector_resize_to(&backend->midx_packs, i); + remove_multi_pack_index(backend); + return error; + } + } + + return 0; +} + +/*********************************************************** + * + * PACKED BACKEND PUBLIC API + * + * Implement the git_odb_backend API calls + * + ***********************************************************/ +static int pack_backend__refresh(git_odb_backend *backend_) +{ + int error; + struct stat st; + git_str path = GIT_STR_INIT; + struct pack_backend *backend = (struct pack_backend *)backend_; + + if (backend->pack_folder == NULL) + return 0; + + if (p_stat(backend->pack_folder, &st) < 0 || !S_ISDIR(st.st_mode)) + return git_odb__error_notfound("failed to refresh packfiles", NULL, 0); + + if (refresh_multi_pack_index(backend) < 0) { + /* + * It is okay if this fails. We will just not use the + * multi-pack-index in this case. + */ + git_error_clear(); + } + + /* reload all packs */ + git_str_sets(&path, backend->pack_folder); + error = git_fs_path_direach(&path, 0, packfile_load__cb, backend); + + git_str_dispose(&path); + git_vector_sort(&backend->packs); + + return error; +} + +static int pack_backend__read_header( + size_t *len_p, git_object_t *type_p, + struct git_odb_backend *backend, const git_oid *oid) +{ + struct git_pack_entry e; + int error; + + GIT_ASSERT_ARG(len_p); + GIT_ASSERT_ARG(type_p); + GIT_ASSERT_ARG(backend); + GIT_ASSERT_ARG(oid); + + if ((error = pack_entry_find(&e, (struct pack_backend *)backend, oid)) < 0) + return error; + + return git_packfile_resolve_header(len_p, type_p, e.p, e.offset); +} + +static int pack_backend__freshen( + git_odb_backend *backend, const git_oid *oid) +{ + struct git_pack_entry e; + time_t now; + int error; + + if ((error = pack_entry_find(&e, (struct pack_backend *)backend, oid)) < 0) + return error; + + now = time(NULL); + + if (e.p->last_freshen > now - FRESHEN_FREQUENCY) + return 0; + + if ((error = git_futils_touch(e.p->pack_name, &now)) < 0) + return error; + + e.p->last_freshen = now; + return 0; +} + +static int pack_backend__read( + void **buffer_p, size_t *len_p, git_object_t *type_p, + git_odb_backend *backend, const git_oid *oid) +{ + struct git_pack_entry e; + git_rawobj raw = {NULL}; + int error; + + if ((error = pack_entry_find(&e, (struct pack_backend *)backend, oid)) < 0 || + (error = git_packfile_unpack(&raw, e.p, &e.offset)) < 0) + return error; + + *buffer_p = raw.data; + *len_p = raw.len; + *type_p = raw.type; + + return 0; +} + +static int pack_backend__read_prefix( + git_oid *out_oid, + void **buffer_p, + size_t *len_p, + git_object_t *type_p, + git_odb_backend *backend, + const git_oid *short_oid, + size_t len) +{ + int error = 0; + + if (len < GIT_OID_MINPREFIXLEN) + error = git_odb__error_ambiguous("prefix length too short"); + + else if (len >= GIT_OID_HEXSZ) { + /* We can fall back to regular read method */ + error = pack_backend__read(buffer_p, len_p, type_p, backend, short_oid); + if (!error) + git_oid_cpy(out_oid, short_oid); + } else { + struct git_pack_entry e; + git_rawobj raw = {NULL}; + + if ((error = pack_entry_find_prefix( + &e, (struct pack_backend *)backend, short_oid, len)) == 0 && + (error = git_packfile_unpack(&raw, e.p, &e.offset)) == 0) + { + *buffer_p = raw.data; + *len_p = raw.len; + *type_p = raw.type; + git_oid_cpy(out_oid, &e.sha1); + } + } + + return error; +} + +static int pack_backend__exists(git_odb_backend *backend, const git_oid *oid) +{ + struct git_pack_entry e; + return pack_entry_find(&e, (struct pack_backend *)backend, oid) == 0; +} + +static int pack_backend__exists_prefix( + git_oid *out, git_odb_backend *backend, const git_oid *short_id, size_t len) +{ + int error; + struct pack_backend *pb = (struct pack_backend *)backend; + struct git_pack_entry e = {0}; + + error = pack_entry_find_prefix(&e, pb, short_id, len); + git_oid_cpy(out, &e.sha1); + return error; +} + +static int pack_backend__foreach(git_odb_backend *_backend, git_odb_foreach_cb cb, void *data) +{ + int error; + struct git_pack_file *p; + struct pack_backend *backend; + unsigned int i; + + GIT_ASSERT_ARG(_backend); + GIT_ASSERT_ARG(cb); + + backend = (struct pack_backend *)_backend; + + /* Make sure we know about the packfiles */ + if ((error = pack_backend__refresh(_backend)) != 0) + return error; + + if (backend->midx && (error = git_midx_foreach_entry(backend->midx, cb, data)) != 0) + return error; + git_vector_foreach(&backend->packs, i, p) { + if ((error = git_pack_foreach_entry(p, cb, data)) != 0) + return error; + } + + return 0; +} + +static int pack_backend__writepack_append(struct git_odb_writepack *_writepack, const void *data, size_t size, git_indexer_progress *stats) +{ + struct pack_writepack *writepack = (struct pack_writepack *)_writepack; + + GIT_ASSERT_ARG(writepack); + + return git_indexer_append(writepack->indexer, data, size, stats); +} + +static int pack_backend__writepack_commit(struct git_odb_writepack *_writepack, git_indexer_progress *stats) +{ + struct pack_writepack *writepack = (struct pack_writepack *)_writepack; + + GIT_ASSERT_ARG(writepack); + + return git_indexer_commit(writepack->indexer, stats); +} + +static void pack_backend__writepack_free(struct git_odb_writepack *_writepack) +{ + struct pack_writepack *writepack; + + if (!_writepack) + return; + + writepack = (struct pack_writepack *)_writepack; + + git_indexer_free(writepack->indexer); + git__free(writepack); +} + +static int pack_backend__writepack(struct git_odb_writepack **out, + git_odb_backend *_backend, + git_odb *odb, + git_indexer_progress_cb progress_cb, + void *progress_payload) +{ + git_indexer_options opts = GIT_INDEXER_OPTIONS_INIT; + struct pack_backend *backend; + struct pack_writepack *writepack; + + GIT_ASSERT_ARG(out); + GIT_ASSERT_ARG(_backend); + + *out = NULL; + + opts.progress_cb = progress_cb; + opts.progress_cb_payload = progress_payload; + + backend = (struct pack_backend *)_backend; + + writepack = git__calloc(1, sizeof(struct pack_writepack)); + GIT_ERROR_CHECK_ALLOC(writepack); + + if (git_indexer_new(&writepack->indexer, + backend->pack_folder, 0, odb, &opts) < 0) { + git__free(writepack); + return -1; + } + + writepack->parent.backend = _backend; + writepack->parent.append = pack_backend__writepack_append; + writepack->parent.commit = pack_backend__writepack_commit; + writepack->parent.free = pack_backend__writepack_free; + + *out = (git_odb_writepack *)writepack; + + return 0; +} + +static int get_idx_path( + git_str *idx_path, + struct pack_backend *backend, + struct git_pack_file *p) +{ + size_t path_len; + int error; + + error = git_fs_path_prettify(idx_path, p->pack_name, backend->pack_folder); + if (error < 0) + return error; + path_len = git_str_len(idx_path); + if (path_len <= strlen(".pack") || git__suffixcmp(git_str_cstr(idx_path), ".pack") != 0) + return git_odb__error_notfound("packfile does not end in .pack", NULL, 0); + path_len -= strlen(".pack"); + error = git_str_splice(idx_path, path_len, strlen(".pack"), ".idx", strlen(".idx")); + if (error < 0) + return error; + + return 0; +} + +static int pack_backend__writemidx(git_odb_backend *_backend) +{ + struct pack_backend *backend; + git_midx_writer *w = NULL; + struct git_pack_file *p; + size_t i; + int error = 0; + + GIT_ASSERT_ARG(_backend); + + backend = (struct pack_backend *)_backend; + + error = git_midx_writer_new(&w, backend->pack_folder); + if (error < 0) + return error; + + git_vector_foreach(&backend->midx_packs, i, p) { + git_str idx_path = GIT_STR_INIT; + error = get_idx_path(&idx_path, backend, p); + if (error < 0) + goto cleanup; + error = git_midx_writer_add(w, git_str_cstr(&idx_path)); + git_str_dispose(&idx_path); + if (error < 0) + goto cleanup; + } + git_vector_foreach(&backend->packs, i, p) { + git_str idx_path = GIT_STR_INIT; + error = get_idx_path(&idx_path, backend, p); + if (error < 0) + goto cleanup; + error = git_midx_writer_add(w, git_str_cstr(&idx_path)); + git_str_dispose(&idx_path); + if (error < 0) + goto cleanup; + } + + /* + * Invalidate the previous midx before writing the new one. + */ + error = remove_multi_pack_index(backend); + if (error < 0) + goto cleanup; + error = git_midx_writer_commit(w); + if (error < 0) + goto cleanup; + error = refresh_multi_pack_index(backend); + +cleanup: + git_midx_writer_free(w); + return error; +} + +static void pack_backend__free(git_odb_backend *_backend) +{ + struct pack_backend *backend; + struct git_pack_file *p; + size_t i; + + if (!_backend) + return; + + backend = (struct pack_backend *)_backend; + + git_vector_foreach(&backend->midx_packs, i, p) + git_mwindow_put_pack(p); + git_vector_foreach(&backend->packs, i, p) + git_mwindow_put_pack(p); + + git_midx_free(backend->midx); + git_vector_free(&backend->midx_packs); + git_vector_free(&backend->packs); + git__free(backend->pack_folder); + git__free(backend); +} + +static int pack_backend__alloc(struct pack_backend **out, size_t initial_size) +{ + struct pack_backend *backend = git__calloc(1, sizeof(struct pack_backend)); + GIT_ERROR_CHECK_ALLOC(backend); + + if (git_vector_init(&backend->midx_packs, 0, NULL) < 0) { + git__free(backend); + return -1; + } + if (git_vector_init(&backend->packs, initial_size, packfile_sort__cb) < 0) { + git_vector_free(&backend->midx_packs); + git__free(backend); + return -1; + } + + backend->parent.version = GIT_ODB_BACKEND_VERSION; + + backend->parent.read = &pack_backend__read; + backend->parent.read_prefix = &pack_backend__read_prefix; + backend->parent.read_header = &pack_backend__read_header; + backend->parent.exists = &pack_backend__exists; + backend->parent.exists_prefix = &pack_backend__exists_prefix; + backend->parent.refresh = &pack_backend__refresh; + backend->parent.foreach = &pack_backend__foreach; + backend->parent.writepack = &pack_backend__writepack; + backend->parent.writemidx = &pack_backend__writemidx; + backend->parent.freshen = &pack_backend__freshen; + backend->parent.free = &pack_backend__free; + + *out = backend; + return 0; +} + +int git_odb_backend_one_pack(git_odb_backend **backend_out, const char *idx) +{ + struct pack_backend *backend = NULL; + struct git_pack_file *packfile = NULL; + + if (pack_backend__alloc(&backend, 1) < 0) + return -1; + + if (git_mwindow_get_pack(&packfile, idx) < 0 || + git_vector_insert(&backend->packs, packfile) < 0) + { + pack_backend__free((git_odb_backend *)backend); + return -1; + } + + *backend_out = (git_odb_backend *)backend; + return 0; +} + +int git_odb_backend_pack(git_odb_backend **backend_out, const char *objects_dir) +{ + int error = 0; + struct pack_backend *backend = NULL; + git_str path = GIT_STR_INIT; + + if (pack_backend__alloc(&backend, 8) < 0) + return -1; + + if (!(error = git_str_joinpath(&path, objects_dir, "pack")) && + git_fs_path_isdir(git_str_cstr(&path))) + { + backend->pack_folder = git_str_detach(&path); + error = pack_backend__refresh((git_odb_backend *)backend); + } + + if (error < 0) { + pack_backend__free((git_odb_backend *)backend); + backend = NULL; + } + + *backend_out = (git_odb_backend *)backend; + + git_str_dispose(&path); + + return error; +} |