Imported Upstream version 2.10.1
[platform/upstream/git.git] / shallow.c
index a0363de..54e2db7 100644 (file)
--- a/shallow.c
+++ b/shallow.c
@@ -1,8 +1,29 @@
 #include "cache.h"
+#include "tempfile.h"
+#include "lockfile.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"
 
 static int is_shallow = -1;
+static struct stat_validity shallow_stat;
+static char *alternate_shallow_file;
+
+void set_alternate_shallow_file(const char *path, int override)
+{
+       if (is_shallow != -1)
+               die("BUG: is_repository_shallow must not be called before set_alternate_shallow_file");
+       if (alternate_shallow_file && !override)
+               return;
+       free(alternate_shallow_file);
+       alternate_shallow_file = xstrdup_or_null(path);
+}
 
 int register_shallow(const unsigned char *sha1)
 {
@@ -10,7 +31,7 @@ int register_shallow(const unsigned char *sha1)
                xmalloc(sizeof(struct commit_graft));
        struct commit *commit = lookup_commit(sha1);
 
-       hashcpy(graft->sha1, sha1);
+       hashcpy(graft->oid.hash, sha1);
        graft->nr_parent = -1;
        if (commit && commit->object.parsed)
                commit->parents = NULL;
@@ -21,15 +42,24 @@ int is_repository_shallow(void)
 {
        FILE *fp;
        char buf[1024];
+       const char *path = alternate_shallow_file;
 
        if (is_shallow >= 0)
                return is_shallow;
 
-       fp = fopen(git_path("shallow"), "r");
-       if (!fp) {
+       if (!path)
+               path = git_path_shallow();
+       /*
+        * 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(&shallow_stat);
                is_shallow = 0;
                return is_shallow;
        }
+       stat_validity_update(&shallow_stat, fileno(fp));
        is_shallow = 1;
 
        while (fgets(buf, sizeof(buf), fp)) {
@@ -49,6 +79,7 @@ struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
        struct commit_list *result = NULL;
        struct object_array stack = OBJECT_ARRAY_INIT;
        struct commit *commit = NULL;
+       struct commit_graft *graft;
 
        while (commit || i < heads->nr || stack.nr) {
                struct commit_list *p;
@@ -70,10 +101,18 @@ struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
                                cur_depth = *(int *)commit->util;
                        }
                }
-               if (parse_commit(commit))
-                       die("invalid commit");
-               commit->object.flags |= not_shallow_flag;
+               parse_commit_or_die(commit);
                cur_depth++;
+               if ((depth != INFINITE_DEPTH && cur_depth >= depth) ||
+                   (is_repository_shallow() && !commit->parents &&
+                    (graft = lookup_commit_graft(commit->object.oid.hash)) != 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) {
                        if (!p->item->util) {
                                int *pointer = xmalloc(sizeof(int));
@@ -85,20 +124,541 @@ struct commit_list *get_shallow_commits(struct object_array *heads, int depth,
                                        continue;
                                *pointer = cur_depth;
                        }
-                       if (cur_depth < depth) {
-                               if (p->next)
-                                       add_object_array(&p->item->object,
-                                                       NULL, &stack);
-                               else {
-                                       commit = p->item;
-                                       cur_depth = *(int *)commit->util;
-                               }
-                       } else {
-                               commit_list_insert(p->item, &result);
-                               p->item->object.flags |= shallow_flag;
+                       if (p->next)
+                               add_object_array(&p->item->object,
+                                               NULL, &stack);
+                       else {
+                               commit = p->item;
+                               cur_depth = *(int *)commit->util;
                        }
                }
        }
 
        return result;
 }
+
+static void check_shallow_file_for_update(void)
+{
+       if (is_shallow == -1)
+               die("BUG: shallow must be initialized by now");
+
+       if (!stat_validity_check(&shallow_stat, git_path_shallow()))
+               die("shallow file has changed since we read it");
+}
+
+#define SEEN_ONLY 1
+#define VERBOSE   2
+
+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 & SEEN_ONLY) {
+               struct commit *c = lookup_commit(graft->oid.hash);
+               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 sha1_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, sha1_to_hex(extra->sha1[i]));
+               strbuf_addch(out, '\n');
+               data.count++;
+       }
+       return data.count;
+}
+
+int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
+                         const struct sha1_array *extra)
+{
+       return write_shallow_commits_1(out, use_pack_protocol, extra, 0);
+}
+
+static struct tempfile temporary_shallow;
+
+const char *setup_temporary_shallow(const struct sha1_array *extra)
+{
+       struct strbuf sb = STRBUF_INIT;
+       int fd;
+
+       if (write_shallow_commits(&sb, 0, extra)) {
+               fd = xmks_tempfile(&temporary_shallow, git_path("shallow_XXXXXX"));
+
+               if (write_in_full(fd, sb.buf, sb.len) != sb.len)
+                       die_errno("failed to write to %s",
+                                 get_tempfile_path(&temporary_shallow));
+               close_tempfile(&temporary_shallow);
+               strbuf_release(&sb);
+               return get_tempfile_path(&temporary_shallow);
+       }
+       /*
+        * is_repository_shallow() sees empty string as "no shallow
+        * file".
+        */
+       return get_tempfile_path(&temporary_shallow);
+}
+
+void setup_alternate_shallow(struct lock_file *shallow_lock,
+                            const char **alternate_shallow_file,
+                            const struct sha1_array *extra)
+{
+       struct strbuf sb = STRBUF_INIT;
+       int fd;
+
+       fd = hold_lock_file_for_update(shallow_lock, git_path_shallow(),
+                                      LOCK_DIE_ON_ERROR);
+       check_shallow_file_for_update();
+       if (write_shallow_commits(&sb, 0, extra)) {
+               if (write_in_full(fd, sb.buf, sb.len) != sb.len)
+                       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(fd, "shallow %s\n", oid_to_hex(&graft->oid));
+       return 0;
+}
+
+void advertise_shallow_grafts(int fd)
+{
+       if (!is_repository_shallow())
+               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".
+ */
+void prune_shallow(int show_only)
+{
+       static struct lock_file shallow_lock;
+       struct strbuf sb = STRBUF_INIT;
+       int fd;
+
+       if (show_only) {
+               write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY | VERBOSE);
+               strbuf_release(&sb);
+               return;
+       }
+       fd = hold_lock_file_for_update(&shallow_lock, git_path_shallow(),
+                                      LOCK_DIE_ON_ERROR);
+       check_shallow_file_for_update();
+       if (write_shallow_commits_1(&sb, 0, NULL, SEEN_ONLY)) {
+               if (write_in_full(fd, sb.buf, sb.len) != sb.len)
+                       die_errno("failed to write to %s",
+                                 get_lock_file_path(&shallow_lock));
+               commit_lock_file(&shallow_lock);
+       } else {
+               unlink(git_path_shallow());
+               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 sha1_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_sha1_file(sa->sha1[i])) {
+                       struct commit_graft *graft;
+                       graft = lookup_commit_graft(sa->sha1[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)
+{
+       unsigned char (*sha1)[20] = info->shallow->sha1;
+       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_sha1_file(sha1[info->theirs[i]]))
+                       dst++;
+       }
+       info->nr_theirs = dst;
+}
+
+define_commit_slab(ref_bitmap, uint32_t *);
+
+struct paint_info {
+       struct ref_bitmap ref_bitmap;
+       unsigned nr_bits;
+       char **slab;
+       char *free, *end;
+       unsigned slab_count;
+};
+
+static uint32_t *paint_alloc(struct paint_info *info)
+{
+       unsigned nr = (info->nr_bits + 31) / 32;
+       unsigned size = nr * sizeof(uint32_t);
+       void *p;
+       if (!info->slab_count || info->free + size > info->end) {
+               info->slab_count++;
+               REALLOC_ARRAY(info->slab, info->slab_count);
+               info->free = xmalloc(COMMIT_SLAB_SIZE);
+               info->slab[info->slab_count - 1] = info->free;
+               info->end = info->free + COMMIT_SLAB_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 unsigned char *sha1,
+                      int id)
+{
+       unsigned int i, nr;
+       struct commit_list *head = NULL;
+       int bitmap_nr = (info->nr_bits + 31) / 32;
+       size_t bitmap_size = st_mult(sizeof(uint32_t), bitmap_nr);
+       uint32_t *tmp = xmalloc(bitmap_size); /* to be freed before return */
+       uint32_t *bitmap = paint_alloc(info);
+       struct commit *c = lookup_commit_reference_gently(sha1, 1);
+       if (!c)
+               return;
+       memset(bitmap, 0, bitmap_size);
+       bitmap[id / 32] |= (1 << (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) {
+                       uint32_t **p_refs = ref_bitmap_at(&info->ref_bitmap,
+                                                         p->item);
+                       if (p->item->object.flags & SEEN)
+                               continue;
+                       if (*p_refs == NULL || *p_refs == *refs)
+                               *p_refs = *refs;
+                       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(oid->hash, 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)
+{
+       unsigned char (*sha1)[20] = info->shallow->sha1;
+       struct sha1_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(sha1[shallow[i]]);
+               c->object.flags |= BOTTOM;
+       }
+
+       for (i = 0; i < ref->nr; i++)
+               paint_down(&pi, ref->sha1[i], i);
+
+       if (used) {
+               int bitmap_size = ((pi.nr_bits + 31) / 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(sha1[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.slab_count; i++)
+               free(pi.slab[i]);
+       free(pi.slab);
+       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(oid->hash, 1);
+       if (ca->commits[ca->nr])
+               ca->nr++;
+       return 0;
+}
+
+static void update_refstatus(int *ref_status, int nr, uint32_t *bitmap)
+{
+       int i;
+       if (!ref_status)
+               return;
+       for (i = 0; i < nr; i++)
+               if (bitmap[i / 32] & (1 << (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)
+{
+       unsigned char (*sha1)[20] = info->shallow->sha1;
+       struct commit *c;
+       uint32_t **bitmap;
+       int dst, i, j;
+       int bitmap_nr = (info->ref->nr + 31) / 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(sha1[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(sha1[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(si->shallow->sha1[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];
+}