diff options
Diffstat (limited to 'third_party/git/shallow.c')
| -rw-r--r-- | third_party/git/shallow.c | 793 |
1 files changed, 793 insertions, 0 deletions
diff --git a/third_party/git/shallow.c b/third_party/git/shallow.c new file mode 100644 index 000000000000..7fd04afed19a --- /dev/null +++ b/third_party/git/shallow.c @@ -0,0 +1,793 @@ +#include "cache.h" +#include "repository.h" +#include "tempfile.h" +#include "lockfile.h" +#include "object-store.h" +#include "commit.h" +#include "tag.h" +#include "pkt-line.h" +#include "remote.h" +#include "refs.h" +#include "sha1-array.h" +#include "diff.h" +#include "revision.h" +#include "commit-slab.h" +#include "list-objects.h" +#include "commit-reach.h" + +void set_alternate_shallow_file(struct repository *r, const char *path, int override) +{ + if (r->parsed_objects->is_shallow != -1) + BUG("is_repository_shallow must not be called before set_alternate_shallow_file"); + if (r->parsed_objects->alternate_shallow_file && !override) + return; + free(r->parsed_objects->alternate_shallow_file); + r->parsed_objects->alternate_shallow_file = xstrdup_or_null(path); +} + +int register_shallow(struct repository *r, const struct object_id *oid) +{ + struct commit_graft *graft = + xmalloc(sizeof(struct commit_graft)); + struct commit *commit = lookup_commit(the_repository, oid); + + oidcpy(&graft->oid, oid); + graft->nr_parent = -1; + if (commit && commit->object.parsed) + commit->parents = NULL; + return register_commit_graft(r, graft, 0); +} + +int is_repository_shallow(struct repository *r) +{ + /* + * NEEDSWORK: This function updates + * r->parsed_objects->{is_shallow,shallow_stat} as a side effect but + * there is no corresponding function to clear them when the shallow + * file is updated. + */ + + FILE *fp; + char buf[1024]; + const char *path = r->parsed_objects->alternate_shallow_file; + + if (r->parsed_objects->is_shallow >= 0) + return r->parsed_objects->is_shallow; + + if (!path) + path = git_path_shallow(r); + /* + * fetch-pack sets '--shallow-file ""' as an indicator that no + * shallow file should be used. We could just open it and it + * will likely fail. But let's do an explicit check instead. + */ + if (!*path || (fp = fopen(path, "r")) == NULL) { + stat_validity_clear(r->parsed_objects->shallow_stat); + r->parsed_objects->is_shallow = 0; + return r->parsed_objects->is_shallow; + } + stat_validity_update(r->parsed_objects->shallow_stat, fileno(fp)); + r->parsed_objects->is_shallow = 1; + + while (fgets(buf, sizeof(buf), fp)) { + struct object_id oid; + if (get_oid_hex(buf, &oid)) + die("bad shallow line: %s", buf); + register_shallow(r, &oid); + } + fclose(fp); + return r->parsed_objects->is_shallow; +} + +/* + * TODO: use "int" elemtype instead of "int *" when/if commit-slab + * supports a "valid" flag. + */ +define_commit_slab(commit_depth, int *); +struct commit_list *get_shallow_commits(struct object_array *heads, int depth, + int shallow_flag, int not_shallow_flag) +{ + int i = 0, cur_depth = 0; + struct commit_list *result = NULL; + struct object_array stack = OBJECT_ARRAY_INIT; + struct commit *commit = NULL; + struct commit_graft *graft; + struct commit_depth depths; + + init_commit_depth(&depths); + while (commit || i < heads->nr || stack.nr) { + struct commit_list *p; + if (!commit) { + if (i < heads->nr) { + int **depth_slot; + commit = (struct commit *) + deref_tag(the_repository, + heads->objects[i++].item, + NULL, 0); + if (!commit || commit->object.type != OBJ_COMMIT) { + commit = NULL; + continue; + } + depth_slot = commit_depth_at(&depths, commit); + if (!*depth_slot) + *depth_slot = xmalloc(sizeof(int)); + **depth_slot = 0; + cur_depth = 0; + } else { + commit = (struct commit *) + object_array_pop(&stack); + cur_depth = **commit_depth_at(&depths, commit); + } + } + parse_commit_or_die(commit); + cur_depth++; + if ((depth != INFINITE_DEPTH && cur_depth >= depth) || + (is_repository_shallow(the_repository) && !commit->parents && + (graft = lookup_commit_graft(the_repository, &commit->object.oid)) != NULL && + graft->nr_parent < 0)) { + commit_list_insert(commit, &result); + commit->object.flags |= shallow_flag; + commit = NULL; + continue; + } + commit->object.flags |= not_shallow_flag; + for (p = commit->parents, commit = NULL; p; p = p->next) { + int **depth_slot = commit_depth_at(&depths, p->item); + if (!*depth_slot) { + *depth_slot = xmalloc(sizeof(int)); + **depth_slot = cur_depth; + } else { + if (cur_depth >= **depth_slot) + continue; + **depth_slot = cur_depth; + } + if (p->next) + add_object_array(&p->item->object, + NULL, &stack); + else { + commit = p->item; + cur_depth = **commit_depth_at(&depths, commit); + } + } + } + for (i = 0; i < depths.slab_count; i++) { + int j; + + if (!depths.slab[i]) + continue; + for (j = 0; j < depths.slab_size; j++) + free(depths.slab[i][j]); + } + clear_commit_depth(&depths); + + return result; +} + +static void show_commit(struct commit *commit, void *data) +{ + commit_list_insert(commit, data); +} + +/* + * Given rev-list arguments, run rev-list. All reachable commits + * except border ones are marked with not_shallow_flag. Border commits + * are marked with shallow_flag. The list of border/shallow commits + * are also returned. + */ +struct commit_list *get_shallow_commits_by_rev_list(int ac, const char **av, + int shallow_flag, + int not_shallow_flag) +{ + struct commit_list *result = NULL, *p; + struct commit_list *not_shallow_list = NULL; + struct rev_info revs; + int both_flags = shallow_flag | not_shallow_flag; + + /* + * SHALLOW (excluded) and NOT_SHALLOW (included) should not be + * set at this point. But better be safe than sorry. + */ + clear_object_flags(both_flags); + + is_repository_shallow(the_repository); /* make sure shallows are read */ + + repo_init_revisions(the_repository, &revs, NULL); + save_commit_buffer = 0; + setup_revisions(ac, av, &revs, NULL); + + if (prepare_revision_walk(&revs)) + die("revision walk setup failed"); + traverse_commit_list(&revs, show_commit, NULL, ¬_shallow_list); + + if (!not_shallow_list) + die("no commits selected for shallow requests"); + + /* Mark all reachable commits as NOT_SHALLOW */ + for (p = not_shallow_list; p; p = p->next) + p->item->object.flags |= not_shallow_flag; + + /* + * mark border commits SHALLOW + NOT_SHALLOW. + * We cannot clear NOT_SHALLOW right now. Imagine border + * commit A is processed first, then commit B, whose parent is + * A, later. If NOT_SHALLOW on A is cleared at step 1, B + * itself is considered border at step 2, which is incorrect. + */ + for (p = not_shallow_list; p; p = p->next) { + struct commit *c = p->item; + struct commit_list *parent; + + if (parse_commit(c)) + die("unable to parse commit %s", + oid_to_hex(&c->object.oid)); + + for (parent = c->parents; parent; parent = parent->next) + if (!(parent->item->object.flags & not_shallow_flag)) { + c->object.flags |= shallow_flag; + commit_list_insert(c, &result); + break; + } + } + free_commit_list(not_shallow_list); + + /* + * Now we can clean up NOT_SHALLOW on border commits. Having + * both flags set can confuse the caller. + */ + for (p = result; p; p = p->next) { + struct object *o = &p->item->object; + if ((o->flags & both_flags) == both_flags) + o->flags &= ~not_shallow_flag; + } + return result; +} + +static void check_shallow_file_for_update(struct repository *r) +{ + if (r->parsed_objects->is_shallow == -1) + BUG("shallow must be initialized by now"); + + if (!stat_validity_check(r->parsed_objects->shallow_stat, + git_path_shallow(r))) + die("shallow file has changed since we read it"); +} + +#define SEEN_ONLY 1 +#define VERBOSE 2 +#define QUICK 4 + +struct write_shallow_data { + struct strbuf *out; + int use_pack_protocol; + int count; + unsigned flags; +}; + +static int write_one_shallow(const struct commit_graft *graft, void *cb_data) +{ + struct write_shallow_data *data = cb_data; + const char *hex = oid_to_hex(&graft->oid); + if (graft->nr_parent != -1) + return 0; + if (data->flags & QUICK) { + if (!has_object_file(&graft->oid)) + return 0; + } else if (data->flags & SEEN_ONLY) { + struct commit *c = lookup_commit(the_repository, &graft->oid); + if (!c || !(c->object.flags & SEEN)) { + if (data->flags & VERBOSE) + printf("Removing %s from .git/shallow\n", + oid_to_hex(&c->object.oid)); + return 0; + } + } + data->count++; + if (data->use_pack_protocol) + packet_buf_write(data->out, "shallow %s", hex); + else { + strbuf_addstr(data->out, hex); + strbuf_addch(data->out, '\n'); + } + return 0; +} + +static int write_shallow_commits_1(struct strbuf *out, int use_pack_protocol, + const struct oid_array *extra, + unsigned flags) +{ + struct write_shallow_data data; + int i; + data.out = out; + data.use_pack_protocol = use_pack_protocol; + data.count = 0; + data.flags = flags; + for_each_commit_graft(write_one_shallow, &data); + if (!extra) + return data.count; + for (i = 0; i < extra->nr; i++) { + strbuf_addstr(out, oid_to_hex(extra->oid + i)); + strbuf_addch(out, '\n'); + data.count++; + } + return data.count; +} + +int write_shallow_commits(struct strbuf *out, int use_pack_protocol, + const struct oid_array *extra) +{ + return write_shallow_commits_1(out, use_pack_protocol, extra, 0); +} + +const char *setup_temporary_shallow(const struct oid_array *extra) +{ + struct tempfile *temp; + struct strbuf sb = STRBUF_INIT; + + if (write_shallow_commits(&sb, 0, extra)) { + temp = xmks_tempfile(git_path("shallow_XXXXXX")); + + if (write_in_full(temp->fd, sb.buf, sb.len) < 0 || + close_tempfile_gently(temp) < 0) + die_errno("failed to write to %s", + get_tempfile_path(temp)); + strbuf_release(&sb); + return get_tempfile_path(temp); + } + /* + * is_repository_shallow() sees empty string as "no shallow + * file". + */ + return ""; +} + +void setup_alternate_shallow(struct lock_file *shallow_lock, + const char **alternate_shallow_file, + const struct oid_array *extra) +{ + struct strbuf sb = STRBUF_INIT; + int fd; + + fd = hold_lock_file_for_update(shallow_lock, + git_path_shallow(the_repository), + LOCK_DIE_ON_ERROR); + check_shallow_file_for_update(the_repository); + if (write_shallow_commits(&sb, 0, extra)) { + if (write_in_full(fd, sb.buf, sb.len) < 0) + die_errno("failed to write to %s", + get_lock_file_path(shallow_lock)); + *alternate_shallow_file = get_lock_file_path(shallow_lock); + } else + /* + * is_repository_shallow() sees empty string as "no + * shallow file". + */ + *alternate_shallow_file = ""; + strbuf_release(&sb); +} + +static int advertise_shallow_grafts_cb(const struct commit_graft *graft, void *cb) +{ + int fd = *(int *)cb; + if (graft->nr_parent == -1) + packet_write_fmt(fd, "shallow %s\n", oid_to_hex(&graft->oid)); + return 0; +} + +void advertise_shallow_grafts(int fd) +{ + if (!is_repository_shallow(the_repository)) + return; + for_each_commit_graft(advertise_shallow_grafts_cb, &fd); +} + +/* + * mark_reachable_objects() should have been run prior to this and all + * reachable commits marked as "SEEN", except when quick_prune is non-zero, + * in which case lines are excised from the shallow file if they refer to + * commits that do not exist (any longer). + */ +void prune_shallow(unsigned options) +{ + struct lock_file shallow_lock = LOCK_INIT; + struct strbuf sb = STRBUF_INIT; + unsigned flags = SEEN_ONLY; + int fd; + + if (options & PRUNE_QUICK) + flags |= QUICK; + + if (options & PRUNE_SHOW_ONLY) { + flags |= VERBOSE; + write_shallow_commits_1(&sb, 0, NULL, flags); + strbuf_release(&sb); + return; + } + fd = hold_lock_file_for_update(&shallow_lock, + git_path_shallow(the_repository), + LOCK_DIE_ON_ERROR); + check_shallow_file_for_update(the_repository); + if (write_shallow_commits_1(&sb, 0, NULL, flags)) { + if (write_in_full(fd, sb.buf, sb.len) < 0) + die_errno("failed to write to %s", + get_lock_file_path(&shallow_lock)); + commit_lock_file(&shallow_lock); + } else { + unlink(git_path_shallow(the_repository)); + rollback_lock_file(&shallow_lock); + } + strbuf_release(&sb); +} + +struct trace_key trace_shallow = TRACE_KEY_INIT(SHALLOW); + +/* + * Step 1, split sender shallow commits into "ours" and "theirs" + * Step 2, clean "ours" based on .git/shallow + */ +void prepare_shallow_info(struct shallow_info *info, struct oid_array *sa) +{ + int i; + trace_printf_key(&trace_shallow, "shallow: prepare_shallow_info\n"); + memset(info, 0, sizeof(*info)); + info->shallow = sa; + if (!sa) + return; + ALLOC_ARRAY(info->ours, sa->nr); + ALLOC_ARRAY(info->theirs, sa->nr); + for (i = 0; i < sa->nr; i++) { + if (has_object_file(sa->oid + i)) { + struct commit_graft *graft; + graft = lookup_commit_graft(the_repository, + &sa->oid[i]); + if (graft && graft->nr_parent < 0) + continue; + info->ours[info->nr_ours++] = i; + } else + info->theirs[info->nr_theirs++] = i; + } +} + +void clear_shallow_info(struct shallow_info *info) +{ + free(info->ours); + free(info->theirs); +} + +/* Step 4, remove non-existent ones in "theirs" after getting the pack */ + +void remove_nonexistent_theirs_shallow(struct shallow_info *info) +{ + struct object_id *oid = info->shallow->oid; + int i, dst; + trace_printf_key(&trace_shallow, "shallow: remove_nonexistent_theirs_shallow\n"); + for (i = dst = 0; i < info->nr_theirs; i++) { + if (i != dst) + info->theirs[dst] = info->theirs[i]; + if (has_object_file(oid + info->theirs[i])) + dst++; + } + info->nr_theirs = dst; +} + +define_commit_slab(ref_bitmap, uint32_t *); + +#define POOL_SIZE (512 * 1024) + +struct paint_info { + struct ref_bitmap ref_bitmap; + unsigned nr_bits; + char **pools; + char *free, *end; + unsigned pool_count; +}; + +static uint32_t *paint_alloc(struct paint_info *info) +{ + unsigned nr = DIV_ROUND_UP(info->nr_bits, 32); + unsigned size = nr * sizeof(uint32_t); + void *p; + if (!info->pool_count || size > info->end - info->free) { + if (size > POOL_SIZE) + BUG("pool size too small for %d in paint_alloc()", + size); + info->pool_count++; + REALLOC_ARRAY(info->pools, info->pool_count); + info->free = xmalloc(POOL_SIZE); + info->pools[info->pool_count - 1] = info->free; + info->end = info->free + POOL_SIZE; + } + p = info->free; + info->free += size; + return p; +} + +/* + * Given a commit SHA-1, walk down to parents until either SEEN, + * UNINTERESTING or BOTTOM is hit. Set the id-th bit in ref_bitmap for + * all walked commits. + */ +static void paint_down(struct paint_info *info, const struct object_id *oid, + unsigned int id) +{ + unsigned int i, nr; + struct commit_list *head = NULL; + int bitmap_nr = DIV_ROUND_UP(info->nr_bits, 32); + size_t bitmap_size = st_mult(sizeof(uint32_t), bitmap_nr); + struct commit *c = lookup_commit_reference_gently(the_repository, oid, + 1); + uint32_t *tmp; /* to be freed before return */ + uint32_t *bitmap; + + if (!c) + return; + + tmp = xmalloc(bitmap_size); + bitmap = paint_alloc(info); + memset(bitmap, 0, bitmap_size); + bitmap[id / 32] |= (1U << (id % 32)); + commit_list_insert(c, &head); + while (head) { + struct commit_list *p; + struct commit *c = pop_commit(&head); + uint32_t **refs = ref_bitmap_at(&info->ref_bitmap, c); + + /* XXX check "UNINTERESTING" from pack bitmaps if available */ + if (c->object.flags & (SEEN | UNINTERESTING)) + continue; + else + c->object.flags |= SEEN; + + if (*refs == NULL) + *refs = bitmap; + else { + memcpy(tmp, *refs, bitmap_size); + for (i = 0; i < bitmap_nr; i++) + tmp[i] |= bitmap[i]; + if (memcmp(tmp, *refs, bitmap_size)) { + *refs = paint_alloc(info); + memcpy(*refs, tmp, bitmap_size); + } + } + + if (c->object.flags & BOTTOM) + continue; + + if (parse_commit(c)) + die("unable to parse commit %s", + oid_to_hex(&c->object.oid)); + + for (p = c->parents; p; p = p->next) { + if (p->item->object.flags & SEEN) + continue; + commit_list_insert(p->item, &head); + } + } + + nr = get_max_object_index(); + for (i = 0; i < nr; i++) { + struct object *o = get_indexed_object(i); + if (o && o->type == OBJ_COMMIT) + o->flags &= ~SEEN; + } + + free(tmp); +} + +static int mark_uninteresting(const char *refname, const struct object_id *oid, + int flags, void *cb_data) +{ + struct commit *commit = lookup_commit_reference_gently(the_repository, + oid, 1); + if (!commit) + return 0; + commit->object.flags |= UNINTERESTING; + mark_parents_uninteresting(commit); + return 0; +} + +static void post_assign_shallow(struct shallow_info *info, + struct ref_bitmap *ref_bitmap, + int *ref_status); +/* + * Step 6(+7), associate shallow commits with new refs + * + * info->ref must be initialized before calling this function. + * + * If used is not NULL, it's an array of info->shallow->nr + * bitmaps. The n-th bit set in the m-th bitmap if ref[n] needs the + * m-th shallow commit from info->shallow. + * + * If used is NULL, "ours" and "theirs" are updated. And if ref_status + * is not NULL it's an array of ref->nr ints. ref_status[i] is true if + * the ref needs some shallow commits from either info->ours or + * info->theirs. + */ +void assign_shallow_commits_to_refs(struct shallow_info *info, + uint32_t **used, int *ref_status) +{ + struct object_id *oid = info->shallow->oid; + struct oid_array *ref = info->ref; + unsigned int i, nr; + int *shallow, nr_shallow = 0; + struct paint_info pi; + + trace_printf_key(&trace_shallow, "shallow: assign_shallow_commits_to_refs\n"); + ALLOC_ARRAY(shallow, info->nr_ours + info->nr_theirs); + for (i = 0; i < info->nr_ours; i++) + shallow[nr_shallow++] = info->ours[i]; + for (i = 0; i < info->nr_theirs; i++) + shallow[nr_shallow++] = info->theirs[i]; + + /* + * Prepare the commit graph to track what refs can reach what + * (new) shallow commits. + */ + nr = get_max_object_index(); + for (i = 0; i < nr; i++) { + struct object *o = get_indexed_object(i); + if (!o || o->type != OBJ_COMMIT) + continue; + + o->flags &= ~(UNINTERESTING | BOTTOM | SEEN); + } + + memset(&pi, 0, sizeof(pi)); + init_ref_bitmap(&pi.ref_bitmap); + pi.nr_bits = ref->nr; + + /* + * "--not --all" to cut short the traversal if new refs + * connect to old refs. If not (e.g. force ref updates) it'll + * have to go down to the current shallow commits. + */ + head_ref(mark_uninteresting, NULL); + for_each_ref(mark_uninteresting, NULL); + + /* Mark potential bottoms so we won't go out of bound */ + for (i = 0; i < nr_shallow; i++) { + struct commit *c = lookup_commit(the_repository, + &oid[shallow[i]]); + c->object.flags |= BOTTOM; + } + + for (i = 0; i < ref->nr; i++) + paint_down(&pi, ref->oid + i, i); + + if (used) { + int bitmap_size = DIV_ROUND_UP(pi.nr_bits, 32) * sizeof(uint32_t); + memset(used, 0, sizeof(*used) * info->shallow->nr); + for (i = 0; i < nr_shallow; i++) { + const struct commit *c = lookup_commit(the_repository, + &oid[shallow[i]]); + uint32_t **map = ref_bitmap_at(&pi.ref_bitmap, c); + if (*map) + used[shallow[i]] = xmemdupz(*map, bitmap_size); + } + /* + * unreachable shallow commits are not removed from + * "ours" and "theirs". The user is supposed to run + * step 7 on every ref separately and not trust "ours" + * and "theirs" any more. + */ + } else + post_assign_shallow(info, &pi.ref_bitmap, ref_status); + + clear_ref_bitmap(&pi.ref_bitmap); + for (i = 0; i < pi.pool_count; i++) + free(pi.pools[i]); + free(pi.pools); + free(shallow); +} + +struct commit_array { + struct commit **commits; + int nr, alloc; +}; + +static int add_ref(const char *refname, const struct object_id *oid, + int flags, void *cb_data) +{ + struct commit_array *ca = cb_data; + ALLOC_GROW(ca->commits, ca->nr + 1, ca->alloc); + ca->commits[ca->nr] = lookup_commit_reference_gently(the_repository, + oid, 1); + if (ca->commits[ca->nr]) + ca->nr++; + return 0; +} + +static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap) +{ + unsigned int i; + if (!ref_status) + return; + for (i = 0; i < nr; i++) + if (bitmap[i / 32] & (1U << (i % 32))) + ref_status[i]++; +} + +/* + * Step 7, reachability test on "ours" at commit level + */ +static void post_assign_shallow(struct shallow_info *info, + struct ref_bitmap *ref_bitmap, + int *ref_status) +{ + struct object_id *oid = info->shallow->oid; + struct commit *c; + uint32_t **bitmap; + int dst, i, j; + int bitmap_nr = DIV_ROUND_UP(info->ref->nr, 32); + struct commit_array ca; + + trace_printf_key(&trace_shallow, "shallow: post_assign_shallow\n"); + if (ref_status) + memset(ref_status, 0, sizeof(*ref_status) * info->ref->nr); + + /* Remove unreachable shallow commits from "theirs" */ + for (i = dst = 0; i < info->nr_theirs; i++) { + if (i != dst) + info->theirs[dst] = info->theirs[i]; + c = lookup_commit(the_repository, &oid[info->theirs[i]]); + bitmap = ref_bitmap_at(ref_bitmap, c); + if (!*bitmap) + continue; + for (j = 0; j < bitmap_nr; j++) + if (bitmap[0][j]) { + update_refstatus(ref_status, info->ref->nr, *bitmap); + dst++; + break; + } + } + info->nr_theirs = dst; + + memset(&ca, 0, sizeof(ca)); + head_ref(add_ref, &ca); + for_each_ref(add_ref, &ca); + + /* Remove unreachable shallow commits from "ours" */ + for (i = dst = 0; i < info->nr_ours; i++) { + if (i != dst) + info->ours[dst] = info->ours[i]; + c = lookup_commit(the_repository, &oid[info->ours[i]]); + bitmap = ref_bitmap_at(ref_bitmap, c); + if (!*bitmap) + continue; + for (j = 0; j < bitmap_nr; j++) + if (bitmap[0][j] && + /* Step 7, reachability test at commit level */ + !in_merge_bases_many(c, ca.nr, ca.commits)) { + update_refstatus(ref_status, info->ref->nr, *bitmap); + dst++; + break; + } + } + info->nr_ours = dst; + + free(ca.commits); +} + +/* (Delayed) step 7, reachability test at commit level */ +int delayed_reachability_test(struct shallow_info *si, int c) +{ + if (si->need_reachability_test[c]) { + struct commit *commit = lookup_commit(the_repository, + &si->shallow->oid[c]); + + if (!si->commits) { + struct commit_array ca; + + memset(&ca, 0, sizeof(ca)); + head_ref(add_ref, &ca); + for_each_ref(add_ref, &ca); + si->commits = ca.commits; + si->nr_commits = ca.nr; + } + + si->reachable[c] = in_merge_bases_many(commit, + si->nr_commits, + si->commits); + si->need_reachability_test[c] = 0; + } + return si->reachable[c]; +} |