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author | lhchavez <lhchavez@lhchavez.com> | 2020-02-17 21:28:13 +0000 |
---|---|---|
committer | lhchavez <lhchavez@lhchavez.com> | 2021-07-26 18:49:18 -0700 |
commit | fff209c400dc054aa05575aa726fd0f03de788c5 (patch) | |
tree | 7954a78f26f450236505bbd5bc307fab83586582 /src/midx.c | |
parent | 2370e4910262f941a3bb0f70ce05ff7a90679fe1 (diff) | |
download | libgit2-fff209c400dc054aa05575aa726fd0f03de788c5.tar.gz |
midx: Add a way to write multi-pack-index files
This change adds the git_midx_writer_* functions to allow to
write and create `multi-pack-index` files from `.idx`/`.pack` files.
Part of: #5399
Diffstat (limited to 'src/midx.c')
-rw-r--r-- | src/midx.c | 396 |
1 files changed, 396 insertions, 0 deletions
diff --git a/src/midx.c b/src/midx.c index d6bb9c1e7..040a43fc4 100644 --- a/src/midx.c +++ b/src/midx.c @@ -7,11 +7,15 @@ #include "midx.h" +#include "array.h" #include "buffer.h" +#include "filebuf.h" #include "futils.h" #include "hash.h" #include "odb.h" #include "pack.h" +#include "path.h" +#include "repository.h" #define MIDX_SIGNATURE 0x4d494458 /* "MIDX" */ #define MIDX_VERSION 1 @@ -36,6 +40,8 @@ struct git_midx_chunk { size_t length; }; +typedef int (*midx_write_cb)(const char *buf, size_t size, void *cb_data); + static int midx_error(const char *message) { git_error_set(GIT_ERROR_ODB, "invalid multi-pack-index file - %s", message); @@ -475,3 +481,393 @@ void git_midx_free(git_midx_file *idx) git_midx_close(idx); git__free(idx); } + +static int packfile__cmp(const void *a_, const void *b_) +{ + const struct git_pack_file *a = a_; + const struct git_pack_file *b = b_; + + return strcmp(a->pack_name, b->pack_name); +} + +int git_midx_writer_new( + git_midx_writer **out, + const char *pack_dir) +{ + git_midx_writer *w = git__calloc(1, sizeof(git_midx_writer)); + GIT_ERROR_CHECK_ALLOC(w); + + if (git_buf_sets(&w->pack_dir, pack_dir) < 0) { + git__free(w); + return -1; + } + git_path_squash_slashes(&w->pack_dir); + + if (git_vector_init(&w->packs, 0, packfile__cmp) < 0) { + git_buf_dispose(&w->pack_dir); + git__free(w); + return -1; + } + + *out = w; + return 0; +} + +void git_midx_writer_free(git_midx_writer *w) +{ + struct git_pack_file *p; + size_t i; + + if (!w) + return; + + git_vector_foreach (&w->packs, i, p) + git_mwindow_put_pack(p); + git_vector_free(&w->packs); + git_buf_dispose(&w->pack_dir); + git__free(w); +} + +int git_midx_writer_add( + git_midx_writer *w, + const char *idx_path) +{ + git_buf idx_path_buf = GIT_BUF_INIT; + int error; + struct git_pack_file *p; + + error = git_path_prettify(&idx_path_buf, idx_path, git_buf_cstr(&w->pack_dir)); + if (error < 0) + return error; + + error = git_mwindow_get_pack(&p, git_buf_cstr(&idx_path_buf)); + git_buf_dispose(&idx_path_buf); + if (error < 0) + return error; + + error = git_vector_insert(&w->packs, p); + if (error < 0) { + git_mwindow_put_pack(p); + return error; + } + + return 0; +} + +typedef git_array_t(git_midx_entry) object_entry_array_t; + +struct object_entry_cb_state { + uint32_t pack_index; + object_entry_array_t *object_entries_array; +}; + +static int object_entry__cb(const git_oid *oid, off64_t offset, void *data) +{ + struct object_entry_cb_state *state = (struct object_entry_cb_state *)data; + + git_midx_entry *entry = git_array_alloc(*state->object_entries_array); + GIT_ERROR_CHECK_ALLOC(entry); + + git_oid_cpy(&entry->sha1, oid); + entry->offset = offset; + entry->pack_index = state->pack_index; + + return 0; +} + +static int object_entry__cmp(const void *a_, const void *b_) +{ + const git_midx_entry *a = (const git_midx_entry *)a_; + const git_midx_entry *b = (const git_midx_entry *)b_; + + return git_oid_cmp(&a->sha1, &b->sha1); +} + +static int write_offset(off64_t offset, midx_write_cb write_cb, void *cb_data) +{ + int error; + uint32_t word; + + word = htonl((uint32_t)((offset >> 32) & 0xffffffffu)); + error = write_cb((const char *)&word, sizeof(word), cb_data); + if (error < 0) + return error; + word = htonl((uint32_t)((offset >> 0) & 0xffffffffu)); + error = write_cb((const char *)&word, sizeof(word), cb_data); + if (error < 0) + return error; + + return 0; +} + +static int write_chunk_header(int chunk_id, off64_t offset, midx_write_cb write_cb, void *cb_data) +{ + uint32_t word = htonl(chunk_id); + int error = write_cb((const char *)&word, sizeof(word), cb_data); + if (error < 0) + return error; + return write_offset(offset, write_cb, cb_data); + + return 0; +} + +static int midx_write_buf(const char *buf, size_t size, void *data) +{ + git_buf *b = (git_buf *)data; + return git_buf_put(b, buf, size); +} + +struct midx_write_hash_context { + midx_write_cb write_cb; + void *cb_data; + git_hash_ctx *ctx; +}; + +static int midx_write_hash(const char *buf, size_t size, void *data) +{ + struct midx_write_hash_context *ctx = (struct midx_write_hash_context *)data; + int error; + + error = git_hash_update(ctx->ctx, buf, size); + if (error < 0) + return error; + + return ctx->write_cb(buf, size, ctx->cb_data); +} + +static int midx_write( + git_midx_writer *w, + midx_write_cb write_cb, + void *cb_data) +{ + int error = 0; + size_t i; + struct git_pack_file *p; + struct git_midx_header hdr = { + .signature = htonl(MIDX_SIGNATURE), + .version = MIDX_VERSION, + .object_id_version = MIDX_OBJECT_ID_VERSION, + .base_midx_files = 0, + }; + uint32_t oid_fanout_count; + uint32_t object_large_offsets_count; + uint32_t oid_fanout[256]; + off64_t offset; + git_buf packfile_names = GIT_BUF_INIT, + oid_lookup = GIT_BUF_INIT, + object_offsets = GIT_BUF_INIT, + object_large_offsets = GIT_BUF_INIT; + git_oid idx_checksum = {{0}}; + git_midx_entry *entry; + object_entry_array_t object_entries_array = GIT_ARRAY_INIT; + git_vector object_entries = GIT_VECTOR_INIT; + git_hash_ctx ctx; + struct midx_write_hash_context hash_cb_data = { + .write_cb = write_cb, + .cb_data = cb_data, + .ctx = &ctx, + }; + + error = git_hash_ctx_init(&ctx); + if (error < 0) + return error; + cb_data = &hash_cb_data; + write_cb = midx_write_hash; + + git_vector_sort(&w->packs); + git_vector_foreach (&w->packs, i, p) { + git_buf relative_index = GIT_BUF_INIT; + struct object_entry_cb_state state = { + .pack_index = (uint32_t)i, + .object_entries_array = &object_entries_array, + }; + size_t path_len; + + error = git_buf_sets(&relative_index, p->pack_name); + if (error < 0) + goto cleanup; + error = git_path_make_relative(&relative_index, git_buf_cstr(&w->pack_dir)); + if (error < 0) { + git_buf_dispose(&relative_index); + goto cleanup; + } + path_len = git_buf_len(&relative_index); + if (path_len <= strlen(".pack") || git__suffixcmp(git_buf_cstr(&relative_index), ".pack") != 0) { + git_buf_dispose(&relative_index); + goto cleanup; + } + path_len -= strlen(".pack"); + + git_buf_put(&packfile_names, git_buf_cstr(&relative_index), path_len); + git_buf_puts(&packfile_names, ".idx"); + git_buf_putc(&packfile_names, '\0'); + git_buf_dispose(&relative_index); + + error = git_pack_foreach_entry_offset(p, object_entry__cb, &state); + if (error < 0) + goto cleanup; + } + + /* Sort the object entries. */ + error = git_vector_init(&object_entries, git_array_size(object_entries_array), object_entry__cmp); + if (error < 0) + goto cleanup; + git_array_foreach (object_entries_array, i, entry) + error = git_vector_set(NULL, &object_entries, i, entry); + git_vector_set_sorted(&object_entries, 0); + git_vector_sort(&object_entries); + git_vector_uniq(&object_entries, NULL); + + /* Pad the packfile names so it is a multiple of four. */ + while (git_buf_len(&packfile_names) & 3) + git_buf_putc(&packfile_names, '\0'); + + /* Fill the OID Fanout table. */ + oid_fanout_count = 0; + for (i = 0; i < 256; i++) { + while (oid_fanout_count < git_vector_length(&object_entries) && + ((const git_midx_entry *)git_vector_get(&object_entries, oid_fanout_count))->sha1.id[0] <= i) + ++oid_fanout_count; + oid_fanout[i] = htonl(oid_fanout_count); + } + + /* Fill the OID Lookup table. */ + git_vector_foreach (&object_entries, i, entry) { + error = git_buf_put(&oid_lookup, (const char *)&entry->sha1, sizeof(entry->sha1)); + if (error < 0) + goto cleanup; + } + + /* Fill the Object Offsets and Object Large Offsets tables. */ + object_large_offsets_count = 0; + git_vector_foreach (&object_entries, i, entry) { + uint32_t word; + + word = htonl((uint32_t)entry->pack_index); + error = git_buf_put(&object_offsets, (const char *)&word, sizeof(word)); + if (error < 0) + goto cleanup; + if (entry->offset >= 0x80000000l) { + word = htonl(0x80000000u | object_large_offsets_count++); + error = write_offset(entry->offset, midx_write_buf, &object_large_offsets); + } else { + word = htonl((uint32_t)entry->offset & 0x7fffffffu); + } + error = git_buf_put(&object_offsets, (const char *)&word, sizeof(word)); + if (error < 0) + goto cleanup; + } + + /* Write the header. */ + hdr.packfiles = htonl((uint32_t)git_vector_length(&w->packs)); + hdr.chunks = 4; + if (git_buf_len(&object_large_offsets) > 0) + hdr.chunks++; + error = write_cb((const char *)&hdr, sizeof(hdr), cb_data); + if (error < 0) + goto cleanup; + + /* Write the chunk headers. */ + offset = sizeof(hdr) + (hdr.chunks + 1) * 12; + error = write_chunk_header(MIDX_PACKFILE_NAMES_ID, offset, write_cb, cb_data); + if (error < 0) + goto cleanup; + offset += git_buf_len(&packfile_names); + error = write_chunk_header(MIDX_OID_FANOUT_ID, offset, write_cb, cb_data); + if (error < 0) + goto cleanup; + offset += sizeof(oid_fanout); + error = write_chunk_header(MIDX_OID_LOOKUP_ID, offset, write_cb, cb_data); + if (error < 0) + goto cleanup; + offset += git_buf_len(&oid_lookup); + error = write_chunk_header(MIDX_OBJECT_OFFSETS_ID, offset, write_cb, cb_data); + if (error < 0) + goto cleanup; + offset += git_buf_len(&object_offsets); + if (git_buf_len(&object_large_offsets) > 0) { + error = write_chunk_header(MIDX_OBJECT_LARGE_OFFSETS_ID, offset, write_cb, cb_data); + if (error < 0) + goto cleanup; + offset += git_buf_len(&object_large_offsets); + } + error = write_chunk_header(0, offset, write_cb, cb_data); + if (error < 0) + goto cleanup; + + /* Write all the chunks. */ + error = write_cb(git_buf_cstr(&packfile_names), git_buf_len(&packfile_names), cb_data); + if (error < 0) + goto cleanup; + error = write_cb((const char *)oid_fanout, sizeof(oid_fanout), cb_data); + if (error < 0) + goto cleanup; + error = write_cb(git_buf_cstr(&oid_lookup), git_buf_len(&oid_lookup), cb_data); + if (error < 0) + goto cleanup; + error = write_cb(git_buf_cstr(&object_offsets), git_buf_len(&object_offsets), cb_data); + if (error < 0) + goto cleanup; + error = write_cb(git_buf_cstr(&object_large_offsets), git_buf_len(&object_large_offsets), cb_data); + if (error < 0) + goto cleanup; + + /* Finalize the checksum and write the trailer. */ + error = git_hash_final(&idx_checksum, &ctx); + if (error < 0) + goto cleanup; + error = write_cb((const char *)&idx_checksum, sizeof(idx_checksum), cb_data); + if (error < 0) + goto cleanup; + +cleanup: + git_array_clear(object_entries_array); + git_vector_free(&object_entries); + git_buf_dispose(&packfile_names); + git_buf_dispose(&oid_lookup); + git_buf_dispose(&object_offsets); + git_buf_dispose(&object_large_offsets); + git_hash_ctx_cleanup(&ctx); + return error; +} + +static int midx_write_filebuf(const char *buf, size_t size, void *data) +{ + git_filebuf *f = (git_filebuf *)data; + return git_filebuf_write(f, buf, size); +} + +int git_midx_writer_commit( + git_midx_writer *w) +{ + int error; + int filebuf_flags = GIT_FILEBUF_DO_NOT_BUFFER; + git_buf midx_path = GIT_BUF_INIT; + git_filebuf output = GIT_FILEBUF_INIT; + + error = git_buf_joinpath(&midx_path, git_buf_cstr(&w->pack_dir), "multi-pack-index"); + if (error < 0) + return error; + + if (git_repository__fsync_gitdir) + filebuf_flags |= GIT_FILEBUF_FSYNC; + error = git_filebuf_open(&output, git_buf_cstr(&midx_path), filebuf_flags, 0644); + git_buf_dispose(&midx_path); + if (error < 0) + return error; + + error = midx_write(w, midx_write_filebuf, &output); + if (error < 0) { + git_filebuf_cleanup(&output); + return error; + } + + return git_filebuf_commit(&output); +} + +int git_midx_writer_dump( + git_buf *midx, + git_midx_writer *w) +{ + return midx_write(w, midx_write_buf, midx); +} |