Imported Upstream version 2.26.0
[platform/upstream/git.git] / builtin / name-rev.c
index 6b9e8c8..a9dcd25 100644 (file)
  */
 #define CUTOFF_DATE_SLOP 86400
 
-typedef struct rev_name {
-       const char *tip_name;
+struct rev_name {
+       char *tip_name;
        timestamp_t taggerdate;
        int generation;
        int distance;
        int from_tag;
-} rev_name;
+};
 
-define_commit_slab(commit_rev_name, struct rev_name *);
+define_commit_slab(commit_rev_name, struct rev_name);
 
 static timestamp_t cutoff = TIME_MAX;
 static struct commit_rev_name rev_names;
@@ -32,16 +32,16 @@ static struct commit_rev_name rev_names;
 /* How many generations are maximally preferred over _one_ merge traversal? */
 #define MERGE_TRAVERSAL_WEIGHT 65535
 
-static struct rev_name *get_commit_rev_name(struct commit *commit)
+static int is_valid_rev_name(const struct rev_name *name)
 {
-       struct rev_name **slot = commit_rev_name_peek(&rev_names, commit);
-
-       return slot ? *slot : NULL;
+       return name && (name->generation || name->tip_name);
 }
 
-static void set_commit_rev_name(struct commit *commit, struct rev_name *name)
+static struct rev_name *get_commit_rev_name(const struct commit *commit)
 {
-       *commit_rev_name_at(&rev_names, commit) = name;
+       struct rev_name *name = commit_rev_name_peek(&rev_names, commit);
+
+       return is_valid_rev_name(name) ? name : NULL;
 }
 
 static int is_better_name(struct rev_name *name,
@@ -81,28 +81,54 @@ static int is_better_name(struct rev_name *name,
 }
 
 static struct rev_name *create_or_update_name(struct commit *commit,
-                                             const char *tip_name,
                                              timestamp_t taggerdate,
                                              int generation, int distance,
                                              int from_tag)
 {
-       struct rev_name *name = get_commit_rev_name(commit);
-
-       if (name == NULL) {
-               name = xmalloc(sizeof(*name));
-               set_commit_rev_name(commit, name);
-               goto copy_data;
-       } else if (is_better_name(name, taggerdate, distance, from_tag)) {
-copy_data:
-               name->tip_name = tip_name;
-               name->taggerdate = taggerdate;
-               name->generation = generation;
-               name->distance = distance;
-               name->from_tag = from_tag;
-
-               return name;
-       } else
-               return NULL;
+       struct rev_name *name = commit_rev_name_at(&rev_names, commit);
+
+       if (is_valid_rev_name(name)) {
+               if (!is_better_name(name, taggerdate, distance, from_tag))
+                       return NULL;
+
+               /*
+                * This string might still be shared with ancestors
+                * (generation > 0).  We can release it here regardless,
+                * because the new name that has just won will be better
+                * for them as well, so name_rev() will replace these
+                * stale pointers when it processes the parents.
+                */
+               if (!name->generation)
+                       free(name->tip_name);
+       }
+
+       name->taggerdate = taggerdate;
+       name->generation = generation;
+       name->distance = distance;
+       name->from_tag = from_tag;
+
+       return name;
+}
+
+static char *get_parent_name(const struct rev_name *name, int parent_number)
+{
+       struct strbuf sb = STRBUF_INIT;
+       size_t len;
+
+       strip_suffix(name->tip_name, "^0", &len);
+       if (name->generation > 0) {
+               strbuf_grow(&sb, len +
+                           1 + decimal_width(name->generation) +
+                           1 + decimal_width(parent_number));
+               strbuf_addf(&sb, "%.*s~%d^%d", (int)len, name->tip_name,
+                           name->generation, parent_number);
+       } else {
+               strbuf_grow(&sb, len +
+                           1 + decimal_width(parent_number));
+               strbuf_addf(&sb, "%.*s^%d", (int)len, name->tip_name,
+                           parent_number);
+       }
+       return strbuf_detach(&sb, NULL);
 }
 
 static void name_rev(struct commit *start_commit,
@@ -113,20 +139,20 @@ static void name_rev(struct commit *start_commit,
        struct commit *commit;
        struct commit **parents_to_queue = NULL;
        size_t parents_to_queue_nr, parents_to_queue_alloc = 0;
-       char *to_free = NULL;
+       struct rev_name *start_name;
 
        parse_commit(start_commit);
        if (start_commit->date < cutoff)
                return;
 
-       if (deref)
-               tip_name = to_free = xstrfmt("%s^0", tip_name);
-
-       if (!create_or_update_name(start_commit, tip_name, taggerdate, 0, 0,
-                                  from_tag)) {
-               free(to_free);
+       start_name = create_or_update_name(start_commit, taggerdate, 0, 0,
+                                          from_tag);
+       if (!start_name)
                return;
-       }
+       if (deref)
+               start_name->tip_name = xstrfmt("%s^0", tip_name);
+       else
+               start_name->tip_name = xstrdup(tip_name);
 
        memset(&queue, 0, sizeof(queue)); /* Use the prio_queue as LIFO */
        prio_queue_put(&queue, start_commit);
@@ -142,7 +168,7 @@ static void name_rev(struct commit *start_commit,
                                parents;
                                parents = parents->next, parent_number++) {
                        struct commit *parent = parents->item;
-                       const char *new_name;
+                       struct rev_name *parent_name;
                        int generation, distance;
 
                        parse_commit(parent);
@@ -150,30 +176,23 @@ static void name_rev(struct commit *start_commit,
                                continue;
 
                        if (parent_number > 1) {
-                               size_t len;
-
-                               strip_suffix(name->tip_name, "^0", &len);
-                               if (name->generation > 0)
-                                       new_name = xstrfmt("%.*s~%d^%d",
-                                                          (int)len,
-                                                          name->tip_name,
-                                                          name->generation,
-                                                          parent_number);
-                               else
-                                       new_name = xstrfmt("%.*s^%d", (int)len,
-                                                          name->tip_name,
-                                                          parent_number);
                                generation = 0;
                                distance = name->distance + MERGE_TRAVERSAL_WEIGHT;
                        } else {
-                               new_name = name->tip_name;
                                generation = name->generation + 1;
                                distance = name->distance + 1;
                        }
 
-                       if (create_or_update_name(parent, new_name, taggerdate,
-                                                 generation, distance,
-                                                 from_tag)) {
+                       parent_name = create_or_update_name(parent, taggerdate,
+                                                           generation,
+                                                           distance, from_tag);
+                       if (parent_name) {
+                               if (parent_number > 1)
+                                       parent_name->tip_name =
+                                               get_parent_name(name,
+                                                               parent_number);
+                               else
+                                       parent_name->tip_name = name->tip_name;
                                ALLOC_GROW(parents_to_queue,
                                           parents_to_queue_nr + 1,
                                           parents_to_queue_alloc);
@@ -228,6 +247,10 @@ static struct tip_table {
        struct tip_table_entry {
                struct object_id oid;
                const char *refname;
+               struct commit *commit;
+               timestamp_t taggerdate;
+               unsigned int from_tag:1;
+               unsigned int deref:1;
        } *table;
        int nr;
        int alloc;
@@ -235,13 +258,18 @@ static struct tip_table {
 } tip_table;
 
 static void add_to_tip_table(const struct object_id *oid, const char *refname,
-                            int shorten_unambiguous)
+                            int shorten_unambiguous, struct commit *commit,
+                            timestamp_t taggerdate, int from_tag, int deref)
 {
        refname = name_ref_abbrev(refname, shorten_unambiguous);
 
        ALLOC_GROW(tip_table.table, tip_table.nr + 1, tip_table.alloc);
        oidcpy(&tip_table.table[tip_table.nr].oid, oid);
        tip_table.table[tip_table.nr].refname = xstrdup(refname);
+       tip_table.table[tip_table.nr].commit = commit;
+       tip_table.table[tip_table.nr].taggerdate = taggerdate;
+       tip_table.table[tip_table.nr].from_tag = from_tag;
+       tip_table.table[tip_table.nr].deref = deref;
        tip_table.nr++;
        tip_table.sorted = 0;
 }
@@ -252,12 +280,30 @@ static int tipcmp(const void *a_, const void *b_)
        return oidcmp(&a->oid, &b->oid);
 }
 
+static int cmp_by_tag_and_age(const void *a_, const void *b_)
+{
+       const struct tip_table_entry *a = a_, *b = b_;
+       int cmp;
+
+       /* Prefer tags. */
+       cmp = b->from_tag - a->from_tag;
+       if (cmp)
+               return cmp;
+
+       /* Older is better. */
+       if (a->taggerdate < b->taggerdate)
+               return -1;
+       return a->taggerdate != b->taggerdate;
+}
+
 static int name_ref(const char *path, const struct object_id *oid, int flags, void *cb_data)
 {
        struct object *o = parse_object(the_repository, oid);
        struct name_ref_data *data = cb_data;
        int can_abbreviate_output = data->tags_only && data->name_only;
        int deref = 0;
+       int from_tag = 0;
+       struct commit *commit = NULL;
        timestamp_t taggerdate = TIME_MAX;
 
        if (data->tags_only && !starts_with(path, "refs/tags/"))
@@ -306,8 +352,6 @@ static int name_ref(const char *path, const struct object_id *oid, int flags, vo
                        return 0;
        }
 
-       add_to_tip_table(oid, path, can_abbreviate_output);
-
        while (o && o->type == OBJ_TAG) {
                struct tag *t = (struct tag *) o;
                if (!t->tagged)
@@ -317,17 +361,35 @@ static int name_ref(const char *path, const struct object_id *oid, int flags, vo
                taggerdate = t->date;
        }
        if (o && o->type == OBJ_COMMIT) {
-               struct commit *commit = (struct commit *)o;
-               int from_tag = starts_with(path, "refs/tags/");
-
+               commit = (struct commit *)o;
+               from_tag = starts_with(path, "refs/tags/");
                if (taggerdate == TIME_MAX)
                        taggerdate = commit->date;
-               path = name_ref_abbrev(path, can_abbreviate_output);
-               name_rev(commit, xstrdup(path), taggerdate, from_tag, deref);
        }
+
+       add_to_tip_table(oid, path, can_abbreviate_output, commit, taggerdate,
+                        from_tag, deref);
        return 0;
 }
 
+static void name_tips(void)
+{
+       int i;
+
+       /*
+        * Try to set better names first, so that worse ones spread
+        * less.
+        */
+       QSORT(tip_table.table, tip_table.nr, cmp_by_tag_and_age);
+       for (i = 0; i < tip_table.nr; i++) {
+               struct tip_table_entry *e = &tip_table.table[i];
+               if (e->commit) {
+                       name_rev(e->commit, e->refname, e->taggerdate,
+                                e->from_tag, e->deref);
+               }
+       }
+}
+
 static const unsigned char *nth_tip_table_ent(size_t ix, void *table_)
 {
        struct tip_table_entry *table = table_;
@@ -357,11 +419,11 @@ static const char *get_exact_ref_match(const struct object *o)
 static const char *get_rev_name(const struct object *o, struct strbuf *buf)
 {
        struct rev_name *n;
-       struct commit *c;
+       const struct commit *c;
 
        if (o->type != OBJ_COMMIT)
                return get_exact_ref_match(o);
-       c = (struct commit *) o;
+       c = (const struct commit *) o;
        n = get_commit_rev_name(c);
        if (!n)
                return NULL;
@@ -540,6 +602,7 @@ int cmd_name_rev(int argc, const char **argv, const char *prefix)
                        cutoff = TIME_MIN;
        }
        for_each_ref(name_ref, &data);
+       name_tips();
 
        if (transform_stdin) {
                char buffer[2048];