diff options
| -rw-r--r-- | Documentation/git-commit-graph.txt | 26 | ||||
| -rw-r--r-- | Documentation/technical/commit-graph-format.txt | 11 | ||||
| -rw-r--r-- | Documentation/technical/commit-graph.txt | 195 | ||||
| -rw-r--r-- | builtin/commit-graph.c | 58 | ||||
| -rw-r--r-- | builtin/commit.c | 2 | ||||
| -rw-r--r-- | builtin/gc.c | 3 | ||||
| -rw-r--r-- | commit-graph.c | 823 | ||||
| -rw-r--r-- | commit-graph.h | 25 | ||||
| -rwxr-xr-x | t/t5318-commit-graph.sh | 2 | ||||
| -rwxr-xr-x | t/t5324-split-commit-graph.sh | 343 |
10 files changed, 1414 insertions, 74 deletions
diff --git a/Documentation/git-commit-graph.txt b/Documentation/git-commit-graph.txt index 624470e198..eb5e7865f0 100644 --- a/Documentation/git-commit-graph.txt +++ b/Documentation/git-commit-graph.txt @@ -10,7 +10,7 @@ SYNOPSIS -------- [verse] 'git commit-graph read' [--object-dir <dir>] -'git commit-graph verify' [--object-dir <dir>] +'git commit-graph verify' [--object-dir <dir>] [--shallow] 'git commit-graph write' <options> [--object-dir <dir>] @@ -26,7 +26,7 @@ OPTIONS Use given directory for the location of packfiles and commit-graph file. This parameter exists to specify the location of an alternate that only has the objects directory, not a full `.git` directory. The - commit-graph file is expected to be at `<dir>/info/commit-graph` and + commit-graph file is expected to be in the `<dir>/info` directory and the packfiles are expected to be in `<dir>/pack`. @@ -51,6 +51,25 @@ or `--stdin-packs`.) + With the `--append` option, include all commits that are present in the existing commit-graph file. ++ +With the `--split` option, write the commit-graph as a chain of multiple +commit-graph files stored in `<dir>/info/commit-graphs`. The new commits +not already in the commit-graph are added in a new "tip" file. This file +is merged with the existing file if the following merge conditions are +met: ++ +* If `--size-multiple=<X>` is not specified, let `X` equal 2. If the new +tip file would have `N` commits and the previous tip has `M` commits and +`X` times `N` is greater than `M`, instead merge the two files into a +single file. ++ +* If `--max-commits=<M>` is specified with `M` a positive integer, and the +new tip file would have more than `M` commits, then instead merge the new +tip with the previous tip. ++ +Finally, if `--expire-time=<datetime>` is not specified, let `datetime` +be the current time. After writing the split commit-graph, delete all +unused commit-graph whose modified times are older than `datetime`. 'read':: @@ -61,6 +80,9 @@ Used for debugging purposes. Read the commit-graph file and verify its contents against the object database. Used to check for corrupted data. ++ +With the `--shallow` option, only check the tip commit-graph file in +a chain of split commit-graphs. EXAMPLES diff --git a/Documentation/technical/commit-graph-format.txt b/Documentation/technical/commit-graph-format.txt index 16452a0504..a4f17441ae 100644 --- a/Documentation/technical/commit-graph-format.txt +++ b/Documentation/technical/commit-graph-format.txt @@ -44,8 +44,9 @@ HEADER: 1-byte number (C) of "chunks" - 1-byte (reserved for later use) - Current clients should ignore this value. + 1-byte number (B) of base commit-graphs + We infer the length (H*B) of the Base Graphs chunk + from this value. CHUNK LOOKUP: @@ -92,6 +93,12 @@ CHUNK DATA: positions for the parents until reaching a value with the most-significant bit on. The other bits correspond to the position of the last parent. + Base Graphs List (ID: {'B', 'A', 'S', 'E'}) [Optional] + This list of H-byte hashes describe a set of B commit-graph files that + form a commit-graph chain. The graph position for the ith commit in this + file's OID Lookup chunk is equal to i plus the number of commits in all + base graphs. If B is non-zero, this chunk must exist. + TRAILER: H-byte HASH-checksum of all of the above. diff --git a/Documentation/technical/commit-graph.txt b/Documentation/technical/commit-graph.txt index fb53341d5e..729fbcb32f 100644 --- a/Documentation/technical/commit-graph.txt +++ b/Documentation/technical/commit-graph.txt @@ -127,6 +127,197 @@ Design Details helpful for these clones, anyway. The commit-graph will not be read or written when shallow commits are present. +Commit Graphs Chains +-------------------- + +Typically, repos grow with near-constant velocity (commits per day). Over time, +the number of commits added by a fetch operation is much smaller than the +number of commits in the full history. By creating a "chain" of commit-graphs, +we enable fast writes of new commit data without rewriting the entire commit +history -- at least, most of the time. + +## File Layout + +A commit-graph chain uses multiple files, and we use a fixed naming convention +to organize these files. Each commit-graph file has a name +`$OBJDIR/info/commit-graphs/graph-{hash}.graph` where `{hash}` is the hex- +valued hash stored in the footer of that file (which is a hash of the file's +contents before that hash). For a chain of commit-graph files, a plain-text +file at `$OBJDIR/info/commit-graphs/commit-graph-chain` contains the +hashes for the files in order from "lowest" to "highest". + +For example, if the `commit-graph-chain` file contains the lines + +``` + {hash0} + {hash1} + {hash2} +``` + +then the commit-graph chain looks like the following diagram: + + +-----------------------+ + | graph-{hash2}.graph | + +-----------------------+ + | + +-----------------------+ + | | + | graph-{hash1}.graph | + | | + +-----------------------+ + | + +-----------------------+ + | | + | | + | | + | graph-{hash0}.graph | + | | + | | + | | + +-----------------------+ + +Let X0 be the number of commits in `graph-{hash0}.graph`, X1 be the number of +commits in `graph-{hash1}.graph`, and X2 be the number of commits in +`graph-{hash2}.graph`. If a commit appears in position i in `graph-{hash2}.graph`, +then we interpret this as being the commit in position (X0 + X1 + i), and that +will be used as its "graph position". The commits in `graph-{hash2}.graph` use these +positions to refer to their parents, which may be in `graph-{hash1}.graph` or +`graph-{hash0}.graph`. We can navigate to an arbitrary commit in position j by checking +its containment in the intervals [0, X0), [X0, X0 + X1), [X0 + X1, X0 + X1 + +X2). + +Each commit-graph file (except the base, `graph-{hash0}.graph`) contains data +specifying the hashes of all files in the lower layers. In the above example, +`graph-{hash1}.graph` contains `{hash0}` while `graph-{hash2}.graph` contains +`{hash0}` and `{hash1}`. + +## Merging commit-graph files + +If we only added a new commit-graph file on every write, we would run into a +linear search problem through many commit-graph files. Instead, we use a merge +strategy to decide when the stack should collapse some number of levels. + +The diagram below shows such a collapse. As a set of new commits are added, it +is determined by the merge strategy that the files should collapse to +`graph-{hash1}`. Thus, the new commits, the commits in `graph-{hash2}` and +the commits in `graph-{hash1}` should be combined into a new `graph-{hash3}` +file. + + +---------------------+ + | | + | (new commits) | + | | + +---------------------+ + | | + +-----------------------+ +---------------------+ + | graph-{hash2} |->| | + +-----------------------+ +---------------------+ + | | | + +-----------------------+ +---------------------+ + | | | | + | graph-{hash1} |->| | + | | | | + +-----------------------+ +---------------------+ + | tmp_graphXXX + +-----------------------+ + | | + | | + | | + | graph-{hash0} | + | | + | | + | | + +-----------------------+ + +During this process, the commits to write are combined, sorted and we write the +contents to a temporary file, all while holding a `commit-graph-chain.lock` +lock-file. When the file is flushed, we rename it to `graph-{hash3}` +according to the computed `{hash3}`. Finally, we write the new chain data to +`commit-graph-chain.lock`: + +``` + {hash3} + {hash0} +``` + +We then close the lock-file. + +## Merge Strategy + +When writing a set of commits that do not exist in the commit-graph stack of +height N, we default to creating a new file at level N + 1. We then decide to +merge with the Nth level if one of two conditions hold: + + 1. `--size-multiple=<X>` is specified or X = 2, and the number of commits in + level N is less than X times the number of commits in level N + 1. + + 2. `--max-commits=<C>` is specified with non-zero C and the number of commits + in level N + 1 is more than C commits. + +This decision cascades down the levels: when we merge a level we create a new +set of commits that then compares to the next level. + +The first condition bounds the number of levels to be logarithmic in the total +number of commits. The second condition bounds the total number of commits in +a `graph-{hashN}` file and not in the `commit-graph` file, preventing +significant performance issues when the stack merges and another process only +partially reads the previous stack. + +The merge strategy values (2 for the size multiple, 64,000 for the maximum +number of commits) could be extracted into config settings for full +flexibility. + +## Deleting graph-{hash} files + +After a new tip file is written, some `graph-{hash}` files may no longer +be part of a chain. It is important to remove these files from disk, eventually. +The main reason to delay removal is that another process could read the +`commit-graph-chain` file before it is rewritten, but then look for the +`graph-{hash}` files after they are deleted. + +To allow holding old split commit-graphs for a while after they are unreferenced, +we update the modified times of the files when they become unreferenced. Then, +we scan the `$OBJDIR/info/commit-graphs/` directory for `graph-{hash}` +files whose modified times are older than a given expiry window. This window +defaults to zero, but can be changed using command-line arguments or a config +setting. + +## Chains across multiple object directories + +In a repo with alternates, we look for the `commit-graph-chain` file starting +in the local object directory and then in each alternate. The first file that +exists defines our chain. As we look for the `graph-{hash}` files for +each `{hash}` in the chain file, we follow the same pattern for the host +directories. + +This allows commit-graphs to be split across multiple forks in a fork network. +The typical case is a large "base" repo with many smaller forks. + +As the base repo advances, it will likely update and merge its commit-graph +chain more frequently than the forks. If a fork updates their commit-graph after +the base repo, then it should "reparent" the commit-graph chain onto the new +chain in the base repo. When reading each `graph-{hash}` file, we track +the object directory containing it. During a write of a new commit-graph file, +we check for any changes in the source object directory and read the +`commit-graph-chain` file for that source and create a new file based on those +files. During this "reparent" operation, we necessarily need to collapse all +levels in the fork, as all of the files are invalid against the new base file. + +It is crucial to be careful when cleaning up "unreferenced" `graph-{hash}.graph` +files in this scenario. It falls to the user to define the proper settings for +their custom environment: + + 1. When merging levels in the base repo, the unreferenced files may still be + referenced by chains from fork repos. + + 2. The expiry time should be set to a length of time such that every fork has + time to recompute their commit-graph chain to "reparent" onto the new base + file(s). + + 3. If the commit-graph chain is updated in the base, the fork will not have + access to the new chain until its chain is updated to reference those files. + (This may change in the future [5].) + Related Links ------------- [0] https://bugs.chromium.org/p/git/issues/detail?id=8 @@ -153,3 +344,7 @@ Related Links [4] https://public-inbox.org/git/20180108154822.54829-1-git@jeffhostetler.com/T/#u A patch to remove the ahead-behind calculation from 'status'. + +[5] https://public-inbox.org/git/f27db281-abad-5043-6d71-cbb083b1c877@gmail.com/ + A discussion of a "two-dimensional graph position" that can allow reading + multiple commit-graph chains at the same time. diff --git a/builtin/commit-graph.c b/builtin/commit-graph.c index d8efa5bab2..38027b83d9 100644 --- a/builtin/commit-graph.c +++ b/builtin/commit-graph.c @@ -5,17 +5,18 @@ #include "parse-options.h" #include "repository.h" #include "commit-graph.h" +#include "object-store.h" static char const * const builtin_commit_graph_usage[] = { N_("git commit-graph [--object-dir <objdir>]"), N_("git commit-graph read [--object-dir <objdir>]"), - N_("git commit-graph verify [--object-dir <objdir>]"), - N_("git commit-graph write [--object-dir <objdir>] [--append] [--reachable|--stdin-packs|--stdin-commits]"), + N_("git commit-graph verify [--object-dir <objdir>] [--shallow]"), + N_("git commit-graph write [--object-dir <objdir>] [--append|--split] [--reachable|--stdin-packs|--stdin-commits] <split options>"), NULL }; static const char * const builtin_commit_graph_verify_usage[] = { - N_("git commit-graph verify [--object-dir <objdir>]"), + N_("git commit-graph verify [--object-dir <objdir>] [--shallow]"), NULL }; @@ -25,7 +26,7 @@ static const char * const builtin_commit_graph_read_usage[] = { }; static const char * const builtin_commit_graph_write_usage[] = { - N_("git commit-graph write [--object-dir <objdir>] [--append] [--reachable|--stdin-packs|--stdin-commits]"), + N_("git commit-graph write [--object-dir <objdir>] [--append|--split] [--reachable|--stdin-packs|--stdin-commits] <split options>"), NULL }; @@ -35,9 +36,10 @@ static struct opts_commit_graph { int stdin_packs; int stdin_commits; int append; + int split; + int shallow; } opts; - static int graph_verify(int argc, const char **argv) { struct commit_graph *graph = NULL; @@ -45,11 +47,14 @@ static int graph_verify(int argc, const char **argv) int open_ok; int fd; struct stat st; + int flags = 0; static struct option builtin_commit_graph_verify_options[] = { OPT_STRING(0, "object-dir", &opts.obj_dir, N_("dir"), N_("The object directory to store the graph")), + OPT_BOOL(0, "shallow", &opts.shallow, + N_("if the commit-graph is split, only verify the tip file")), OPT_END(), }; @@ -59,21 +64,27 @@ static int graph_verify(int argc, const char **argv) if (!opts.obj_dir) opts.obj_dir = get_object_directory(); + if (opts.shallow) + flags |= COMMIT_GRAPH_VERIFY_SHALLOW; graph_name = get_commit_graph_filename(opts.obj_dir); open_ok = open_commit_graph(graph_name, &fd, &st); - if (!open_ok && errno == ENOENT) - return 0; - if (!open_ok) + if (!open_ok && errno != ENOENT) die_errno(_("Could not open commit-graph '%s'"), graph_name); - graph = load_commit_graph_one_fd_st(fd, &st); + FREE_AND_NULL(graph_name); + if (open_ok) + graph = load_commit_graph_one_fd_st(fd, &st); + else + graph = read_commit_graph_one(the_repository, opts.obj_dir); + + /* Return failure if open_ok predicted success */ if (!graph) - return 1; + return !!open_ok; UNLEAK(graph); - return verify_commit_graph(the_repository, graph); + return verify_commit_graph(the_repository, graph, flags); } static int graph_read(int argc, const char **argv) @@ -135,6 +146,7 @@ static int graph_read(int argc, const char **argv) } extern int read_replace_refs; +static struct split_commit_graph_opts split_opts; static int graph_write(int argc, const char **argv) { @@ -156,9 +168,21 @@ static int graph_write(int argc, const char **argv) N_("start walk at commits listed by stdin")), OPT_BOOL(0, "append", &opts.append, N_("include all commits already in the commit-graph file")), + OPT_BOOL(0, "split", &opts.split, + N_("allow writing an incremental commit-graph file")), + OPT_INTEGER(0, "max-commits", &split_opts.max_commits, + N_("maximum number of commits in a non-base split commit-graph")), + OPT_INTEGER(0, "size-multiple", &split_opts.size_multiple, + N_("maximum ratio between two levels of a split commit-graph")), + OPT_EXPIRY_DATE(0, "expire-time", &split_opts.expire_time, + N_("maximum number of commits in a non-base split commit-graph")), OPT_END(), }; + split_opts.size_multiple = 2; + split_opts.max_commits = 0; + split_opts.expire_time = 0; + argc = parse_options(argc, argv, NULL, builtin_commit_graph_write_options, builtin_commit_graph_write_usage, 0); @@ -169,11 +193,16 @@ static int graph_write(int argc, const char **argv) opts.obj_dir = get_object_directory(); if (opts.append) flags |= COMMIT_GRAPH_APPEND; + if (opts.split) + flags |= COMMIT_GRAPH_SPLIT; read_replace_refs = 0; - if (opts.reachable) - return write_commit_graph_reachable(opts.obj_dir, flags); + if (opts.reachable) { + if (write_commit_graph_reachable(opts.obj_dir, flags, &split_opts)) + return 1; + return 0; + } string_list_init(&lines, 0); if (opts.stdin_packs || opts.stdin_commits) { @@ -193,7 +222,8 @@ static int graph_write(int argc, const char **argv) if (write_commit_graph(opts.obj_dir, pack_indexes, commit_hex, - flags)) + flags, + &split_opts)) result = 1; UNLEAK(lines); diff --git a/builtin/commit.c b/builtin/commit.c index 3b561c2a75..3e4b5bfe4e 100644 --- a/builtin/commit.c +++ b/builtin/commit.c @@ -1687,7 +1687,7 @@ int cmd_commit(int argc, const char **argv, const char *prefix) "not exceeded, and then \"git restore --staged :/\" to recover.")); if (git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) && - write_commit_graph_reachable(get_object_directory(), 0)) + write_commit_graph_reachable(get_object_directory(), 0, NULL)) return 1; repo_rerere(the_repository, 0); diff --git a/builtin/gc.c b/builtin/gc.c index be8e0bfcbe..c18efadda5 100644 --- a/builtin/gc.c +++ b/builtin/gc.c @@ -687,7 +687,8 @@ int cmd_gc(int argc, const char **argv, const char *prefix) if (gc_write_commit_graph && write_commit_graph_reachable(get_object_directory(), - !quiet && !daemonized ? COMMIT_GRAPH_PROGRESS : 0)) + !quiet && !daemonized ? COMMIT_GRAPH_PROGRESS : 0, + NULL)) return 1; if (auto_gc && too_many_loose_objects()) diff --git a/commit-graph.c b/commit-graph.c index 8cc1d1d6c3..b3c4de79b6 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -22,6 +22,7 @@ #define GRAPH_CHUNKID_OIDLOOKUP 0x4f49444c /* "OIDL" */ #define GRAPH_CHUNKID_DATA 0x43444154 /* "CDAT" */ #define GRAPH_CHUNKID_EXTRAEDGES 0x45444745 /* "EDGE" */ +#define GRAPH_CHUNKID_BASE 0x42415345 /* "BASE" */ #define GRAPH_DATA_WIDTH (the_hash_algo->rawsz + 16) @@ -42,7 +43,28 @@ char *get_commit_graph_filename(const char *obj_dir) { - return xstrfmt("%s/info/commit-graph", obj_dir); + char *filename = xstrfmt("%s/info/commit-graph", obj_dir); + char *normalized = xmalloc(strlen(filename) + 1); + normalize_path_copy(normalized, filename); + free(filename); + return normalized; +} + +static char *get_split_graph_filename(const char *obj_dir, + const char *oid_hex) +{ + char *filename = xstrfmt("%s/info/commit-graphs/graph-%s.graph", + obj_dir, + oid_hex); + char *normalized = xmalloc(strlen(filename) + 1); + normalize_path_copy(normalized, filename); + free(filename); + return normalized; +} + +static char *get_chain_filename(const char *obj_dir) +{ + return xstrfmt("%s/info/commit-graphs/commit-graph-chain", obj_dir); } static uint8_t oid_version(void) @@ -249,6 +271,12 @@ struct commit_graph *parse_commit_graph(void *graph_map, int fd, else graph->chunk_extra_edges = data + chunk_offset; break; + + case GRAPH_CHUNKID_BASE: + if (graph->chunk_base_graphs) + chunk_repeated = 1; + else + graph->chunk_base_graphs = data + chunk_offset; } if (chunk_repeated) { @@ -267,6 +295,8 @@ struct commit_graph *parse_commit_graph(void *graph_map, int fd, last_chunk_offset = chunk_offset; } + hashcpy(graph->oid.hash, graph->data + graph->data_len - graph->hash_len); + if (verify_commit_graph_lite(graph)) { free(graph); return NULL; @@ -280,26 +310,151 @@ static struct commit_graph *load_commit_graph_one(const char *graph_file) struct stat st; int fd; + struct commit_graph *g; int open_ok = open_commit_graph(graph_file, &fd, &st); if (!open_ok) return NULL; - return load_commit_graph_one_fd_st(fd, &st); + g = load_commit_graph_one_fd_st(fd, &st); + + if (g) + g->filename = xstrdup(graph_file); + + return g; +} + +static struct commit_graph *load_commit_graph_v1(struct repository *r, const char *obj_dir) +{ + char *graph_name = get_commit_graph_filename(obj_dir); + struct commit_graph *g = load_commit_graph_one(graph_name); + free(graph_name); + + if (g) + g->obj_dir = obj_dir; + + return g; +} + +static int add_graph_to_chain(struct commit_graph *g, + struct commit_graph *chain, + struct object_id *oids, + int n) +{ + struct commit_graph *cur_g = chain; + + if (n && !g->chunk_base_graphs) { + warning(_("commit-graph has no base graphs chunk")); + return 0; + } + + while (n) { + n--; + + if (!cur_g || + !oideq(&oids[n], &cur_g->oid) || + !hasheq(oids[n].hash, g->chunk_base_graphs + g->hash_len * n)) { + warning(_("commit-graph chain does not match")); + return 0; + } + + cur_g = cur_g->base_graph; + } + + g->base_graph = chain; + + if (chain) + g->num_commits_in_base = chain->num_commits + chain->num_commits_in_base; + + return 1; +} + +static struct commit_graph *load_commit_graph_chain(struct repository *r, const char *obj_dir) +{ + struct commit_graph *graph_chain = NULL; + struct strbuf line = STRBUF_INIT; + struct stat st; + struct object_id *oids; + int i = 0, valid = 1, count; + char *chain_name = get_chain_filename(obj_dir); + FILE *fp; + int stat_res; + + fp = fopen(chain_name, "r"); + stat_res = stat(chain_name, &st); + free(chain_name); + + if (!fp || + stat_res || + st.st_size <= the_hash_algo->hexsz) + return NULL; + + count = st.st_size / (the_hash_algo->hexsz + 1); + oids = xcalloc(count, sizeof(struct object_id)); + + prepare_alt_odb(r); + + for (i = 0; i < count; i++) { + struct object_directory *odb; + + if (strbuf_getline_lf(&line, fp) == EOF) + break; + + if (get_oid_hex(line.buf, &oids[i])) { + warning(_("invalid commit-graph chain: line '%s' not a hash"), + line.buf); + valid = 0; + break; + } + + valid = 0; + for (odb = r->objects->odb; odb; odb = odb->next) { + char *graph_name = get_split_graph_filename(odb->path, line.buf); + struct commit_graph *g = load_commit_graph_one(graph_name); + + free(graph_name); + + if (g) { + g->obj_dir = odb->path; + + if (add_graph_to_chain(g, graph_chain, oids, i)) { + graph_chain = g; + valid = 1; + } + + break; + } + } + + if (!valid) { + warning(_("unable to find all commit-graph files")); + break; + } + } + + free(oids); + fclose(fp); + + return graph_chain; +} + +struct commit_graph *read_commit_graph_one(struct repository *r, const char *obj_dir) +{ + struct commit_graph *g = load_commit_graph_v1(r, obj_dir); + + if (!g) + g = load_commit_graph_chain(r, obj_dir); + + return g; } static void prepare_commit_graph_one(struct repository *r, const char *obj_dir) { - char *graph_name; if (r->objects->commit_graph) return; - graph_name = get_commit_graph_filename(obj_dir); - r->objects->commit_graph = - load_commit_graph_one(graph_name); - - FREE_AND_NULL(graph_name); + r->objects->commit_graph = read_commit_graph_one(r, obj_dir); } /* @@ -361,9 +516,18 @@ int generation_numbers_enabled(struct repository *r) return !!first_generation; } +static void close_commit_graph_one(struct commit_graph *g) +{ + if (!g) + return; + + close_commit_graph_one(g->base_graph); + free_commit_graph(g); +} + void close_commit_graph(struct raw_object_store *o) { - free_commit_graph(o->commit_graph); + close_commit_graph_one(o->commit_graph); o->commit_graph = NULL; } @@ -373,18 +537,38 @@ static int bsearch_graph(struct commit_graph *g, struct object_id *oid, uint32_t g->chunk_oid_lookup, g->hash_len, pos); } +static void load_oid_from_graph(struct commit_graph *g, + uint32_t pos, + struct object_id *oid) +{ + uint32_t lex_index; + + while (g && pos < g->num_commits_in_base) + g = g->base_graph; + + if (!g) + BUG("NULL commit-graph"); + + if (pos >= g->num_commits + g->num_commits_in_base) + die(_("invalid commit position. commit-graph is likely corrupt")); + + lex_index = pos - g->num_commits_in_base; + + hashcpy(oid->hash, g->chunk_oid_lookup + g->hash_len * lex_index); +} + static struct commit_list **insert_parent_or_die(struct repository *r, struct commit_graph *g, - uint64_t pos, + uint32_t pos, struct commit_list **pptr) { struct commit *c; struct object_id oid; - if (pos >= g->num_commits) - die("invalid parent position %"PRIu64, pos); + if (pos >= g->num_commits + g->num_commits_in_base) + die("invalid parent position %"PRIu32, pos); - hashcpy(oid.hash, g->chunk_oid_lookup + g->hash_len * pos); + load_oid_from_graph(g, pos, &oid); c = lookup_commit(r, &oid); if (!c) die(_("could not find commit %s"), oid_to_hex(&oid)); @@ -394,7 +578,14 @@ static struct commit_list **insert_parent_or_die(struct repository *r, static void fill_commit_graph_info(struct commit *item, struct commit_graph *g, uint32_t pos) { - const unsigned char *commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * pos; + const unsigned char *commit_data; + uint32_t lex_index; + + while (pos < g->num_commits_in_base) + g = g->base_graph; + + lex_index = pos - g->num_commits_in_base; + commit_data = g->chunk_commit_data + GRAPH_DATA_WIDTH * lex_index; item->graph_pos = pos; item->generation = get_be32(commit_data + g->hash_len + 8) >> 2; } @@ -412,10 +603,25 @@ static int fill_commit_in_graph(struct repository *r, uint32_t *parent_data_ptr; uint64_t date_low, date_high; struct commit_list **pptr; - const unsigned char *commit_data = g->chunk_commit_data + (g->hash_len + 16) * pos; + const unsigned char *commit_data; + uint32_t lex_index; - item->object.parsed = 1; + while (pos < g->num_commits_in_base) + g = g->base_graph; + + if (pos >= g->num_commits + g->num_commits_in_base) + die(_("invalid commit position. commit-graph is likely corrupt")); + + /* + * Store the "full" position, but then use the + * "local" position for the rest of the calculation. + */ item->graph_pos = pos; + lex_index = pos - g->num_commits_in_base; + + commit_data = g->chunk_commit_data + (g->hash_len + 16) * lex_index; + + item->object.parsed = 1; set_commit_tree(item, NULL); @@ -459,7 +665,18 @@ static int find_commit_in_graph(struct commit *item, struct commit_graph *g, uin *pos = item->graph_pos; return 1; } else { - return bsearch_graph(g, &(item->object.oid), pos); + struct commit_graph *cur_g = g; + uint32_t lex_index; + + while (cur_g && !bsearch_graph(cur_g, &(item->object.oid), &lex_index)) + cur_g = cur_g->base_graph; + + if (cur_g) { + *pos = lex_index + cur_g->num_commits_in_base; + return 1; + } + + return 0; } } @@ -499,8 +716,13 @@ static struct tree *load_tree_for_commit(struct repository *r, struct commit *c) { struct object_id oid; - const unsigned char *commit_data = g->chunk_commit_data + - GRAPH_DATA_WIDTH * (c->graph_pos); + const unsigned char *commit_data; + + while (c->graph_pos < g->num_commits_in_base) + g = g->base_graph; + + commit_data = g->chunk_commit_data + + GRAPH_DATA_WIDTH * (c->graph_pos - g->num_commits_in_base); hashcpy(oid.hash, commit_data); set_commit_tree(c, lookup_tree(r, &oid)); @@ -539,7 +761,7 @@ struct packed_oid_list { struct write_commit_graph_context { struct repository *r; - const char *obj_dir; + char *obj_dir; char *graph_name; struct packed_oid_list oids; struct packed_commit_list commits; @@ -548,8 +770,21 @@ struct write_commit_graph_context { struct progress *progress; int progress_done; uint64_t progress_cnt; + + char *base_graph_name; + int num_commit_graphs_before; + int num_commit_graphs_after; + char **commit_graph_filenames_before; + char **commit_graph_filenames_after; + char **commit_graph_hash_after; + uint32_t new_num_commits_in_base; + struct commit_graph *new_base_graph; + unsigned append:1, - report_progress:1; + report_progress:1, + split:1; + + const struct split_commit_graph_opts *split_opts; }; static void write_graph_chunk_fanout(struct hashfile *f, @@ -619,6 +854,16 @@ static void write_graph_chunk_data(struct hashfile *f, int hash_len, ctx->commits.nr, commit_to_sha1); + if (edge_value >= 0) + edge_value += ctx->new_num_commits_in_base; + else { + uint32_t pos; + if (find_commit_in_graph(parent->item, + ctx->new_base_graph, + &pos)) + edge_value = pos; + } + if (edge_value < 0) BUG("missing parent %s for commit %s", oid_to_hex(&parent->item->object.oid), @@ -639,6 +884,17 @@ static void write_graph_chunk_data(struct hashfile *f, int hash_len, ctx->commits.list, ctx->commits.nr, commit_to_sha1); + + if (edge_value >= 0) + edge_value += ctx->new_num_commits_in_base; + else { + uint32_t pos; + if (find_commit_in_graph(parent->item, + ctx->new_base_graph, + &pos)) + edge_value = pos; + } + if (edge_value < 0) BUG("missing parent %s for commit %s", oid_to_hex(&parent->item->object.oid), @@ -696,6 +952,16 @@ static void write_graph_chunk_extra_edges(struct hashfile *f, ctx->commits.nr, commit_to_sha1); + if (edge_value >= 0) + edge_value += ctx->new_num_commits_in_base; + else { + uint32_t pos; + if (find_commit_in_graph(parent->item, + ctx->new_base_graph, + &pos)) + edge_value = pos; + } + if (edge_value < 0) BUG("missing parent %s for commit %s", oid_to_hex(&parent->item->object.oid), @@ -710,7 +976,7 @@ static void write_graph_chunk_extra_edges(struct hashfile *f, } } -static int commit_compare(const void *_a, const void *_b) +static int oid_compare(const void *_a, const void *_b) { const struct object_id *a = (const struct object_id *)_a; const struct object_id *b = (const struct object_id *)_b; @@ -787,7 +1053,13 @@ static void close_reachable(struct write_commit_graph_context *ctx) display_progress(ctx->progress, i + 1); commit = lookup_commit(ctx->r, &ctx->oids.list[i]); - if (commit && !parse_commit_no_graph(commit)) + if (!commit) + continue; + if (ctx->split) { + if (!parse_commit(commit) && + commit->graph_pos == COMMIT_NOT_FROM_GRAPH) + add_missing_parents(ctx, commit); + } else if (!parse_commit_no_graph(commit)) add_missing_parents(ctx, commit); } stop_progress(&ctx->progress); @@ -861,14 +1133,15 @@ static int add_ref_to_list(const char *refname, return 0; } -int write_commit_graph_reachable(const char *obj_dir, unsigned int flags) +int write_commit_graph_reachable(const char *obj_dir, unsigned int flags, + const struct split_commit_graph_opts *split_opts) { struct string_list list = STRING_LIST_INIT_DUP; int result; for_each_ref(add_ref_to_list, &list); result = write_commit_graph(obj_dir, NULL, &list, - flags); + flags, split_opts); string_list_clear(&list, 0); return result; @@ -979,12 +1252,20 @@ static uint32_t count_distinct_commits(struct write_commit_graph_context *ctx) _("Counting distinct commits in commit graph"), ctx->oids.nr); display_progress(ctx->progress, 0); /* TODO: Measure QSORT() progress */ - QSORT(ctx->oids.list, ctx->oids.nr, commit_compare); + QSORT(ctx->oids.list, ctx->oids.nr, oid_compare); for (i = 1; i < ctx->oids.nr; i++) { display_progress(ctx->progress, i + 1); - if (!oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i])) + if (!oideq(&ctx->oids.list[i - 1], &ctx->oids.list[i])) { + if (ctx->split) { + |