1 files changed, 636 insertions, 0 deletions

diff --git a/builtin/name-rev.c b/builtin/name-rev.c
new file mode 100644
index 0000000..a9dcd25
--- /dev/null
+++ b/builtin/name-rev.c
@@ -0,0 +1,636 @@
+#include "builtin.h"
+#include "cache.h"
+#include "repository.h"
+#include "config.h"
+#include "commit.h"
+#include "tag.h"
+#include "refs.h"
+#include "parse-options.h"
+#include "prio-queue.h"
+#include "sha1-lookup.h"
+#include "commit-slab.h"
+
+/*
+ * One day.  See the 'name a rev shortly after epoch' test in t6120 when
+ * changing this value
+ */
+#define CUTOFF_DATE_SLOP 86400
+
+struct rev_name {
+	char *tip_name;
+	timestamp_t taggerdate;
+	int generation;
+	int distance;
+	int from_tag;
+};
+
+define_commit_slab(commit_rev_name, struct rev_name);
+
+static timestamp_t cutoff = TIME_MAX;
+static struct commit_rev_name rev_names;
+
+/* How many generations are maximally preferred over _one_ merge traversal? */
+#define MERGE_TRAVERSAL_WEIGHT 65535
+
+static int is_valid_rev_name(const struct rev_name *name)
+{
+	return name && (name->generation || name->tip_name);
+}
+
+static struct rev_name *get_commit_rev_name(const struct commit *commit)
+{
+	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,
+			  timestamp_t taggerdate,
+			  int distance,
+			  int from_tag)
+{
+	/*
+	 * When comparing names based on tags, prefer names
+	 * based on the older tag, even if it is farther away.
+	 */
+	if (from_tag && name->from_tag)
+		return (name->taggerdate > taggerdate ||
+			(name->taggerdate == taggerdate &&
+			 name->distance > distance));
+
+	/*
+	 * We know that at least one of them is a non-tag at this point.
+	 * favor a tag over a non-tag.
+	 */
+	if (name->from_tag != from_tag)
+		return from_tag;
+
+	/*
+	 * We are now looking at two non-tags.  Tiebreak to favor
+	 * shorter hops.
+	 */
+	if (name->distance != distance)
+		return name->distance > distance;
+
+	/* ... or tiebreak to favor older date */
+	if (name->taggerdate != taggerdate)
+		return name->taggerdate > taggerdate;
+
+	/* keep the current one if we cannot decide */
+	return 0;
+}
+
+static struct rev_name *create_or_update_name(struct commit *commit,
+					      timestamp_t taggerdate,
+					      int generation, int distance,
+					      int from_tag)
+{
+	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,
+		const char *tip_name, timestamp_t taggerdate,
+		int from_tag, int deref)
+{
+	struct prio_queue queue;
+	struct commit *commit;
+	struct commit **parents_to_queue = NULL;
+	size_t parents_to_queue_nr, parents_to_queue_alloc = 0;
+	struct rev_name *start_name;
+
+	parse_commit(start_commit);
+	if (start_commit->date < cutoff)
+		return;
+
+	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);
+
+	while ((commit = prio_queue_get(&queue))) {
+		struct rev_name *name = get_commit_rev_name(commit);
+		struct commit_list *parents;
+		int parent_number = 1;
+
+		parents_to_queue_nr = 0;
+
+		for (parents = commit->parents;
+				parents;
+				parents = parents->next, parent_number++) {
+			struct commit *parent = parents->item;
+			struct rev_name *parent_name;
+			int generation, distance;
+
+			parse_commit(parent);
+			if (parent->date < cutoff)
+				continue;
+
+			if (parent_number > 1) {
+				generation = 0;
+				distance = name->distance + MERGE_TRAVERSAL_WEIGHT;
+			} else {
+				generation = name->generation + 1;
+				distance = name->distance + 1;
+			}
+
+			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);
+				parents_to_queue[parents_to_queue_nr] = parent;
+				parents_to_queue_nr++;
+			}
+		}
+
+		/* The first parent must come out first from the prio_queue */
+		while (parents_to_queue_nr)
+			prio_queue_put(&queue,
+				       parents_to_queue[--parents_to_queue_nr]);
+	}
+
+	clear_prio_queue(&queue);
+	free(parents_to_queue);
+}
+
+static int subpath_matches(const char *path, const char *filter)
+{
+	const char *subpath = path;
+
+	while (subpath) {
+		if (!wildmatch(filter, subpath, 0))
+			return subpath - path;
+		subpath = strchr(subpath, '/');
+		if (subpath)
+			subpath++;
+	}
+	return -1;
+}
+
+static const char *name_ref_abbrev(const char *refname, int shorten_unambiguous)
+{
+	if (shorten_unambiguous)
+		refname = shorten_unambiguous_ref(refname, 0);
+	else if (skip_prefix(refname, "refs/heads/", &refname))
+		; /* refname already advanced */
+	else
+		skip_prefix(refname, "refs/", &refname);
+	return refname;
+}
+
+struct name_ref_data {
+	int tags_only;
+	int name_only;
+	struct string_list ref_filters;
+	struct string_list exclude_filters;
+};
+
+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;
+	int sorted;
+} tip_table;
+
+static void add_to_tip_table(const struct object_id *oid, const char *refname,
+			     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;
+}
+
+static int tipcmp(const void *a_, const void *b_)
+{
+	const struct tip_table_entry *a = a_, *b = 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/"))
+		return 0;
+
+	if (data->exclude_filters.nr) {
+		struct string_list_item *item;
+
+		for_each_string_list_item(item, &data->exclude_filters) {
+			if (subpath_matches(path, item->string) >= 0)
+				return 0;
+		}
+	}
+
+	if (data->ref_filters.nr) {
+		struct string_list_item *item;
+		int matched = 0;
+
+		/* See if any of the patterns match. */
+		for_each_string_list_item(item, &data->ref_filters) {
+			/*
+			 * Check all patterns even after finding a match, so
+			 * that we can see if a match with a subpath exists.
+			 * When a user asked for 'refs/tags/v*' and 'v1.*',
+			 * both of which match, the user is showing her
+			 * willingness to accept a shortened output by having
+			 * the 'v1.*' in the acceptable refnames, so we
+			 * shouldn't stop when seeing 'refs/tags/v1.4' matches
+			 * 'refs/tags/v*'.  We should show it as 'v1.4'.
+			 */
+			switch (subpath_matches(path, item->string)) {
+			case -1: /* did not match */
+				break;
+			case 0: /* matched fully */
+				matched = 1;
+				break;
+			default: /* matched subpath */
+				matched = 1;
+				can_abbreviate_output = 1;
+				break;
+			}
+		}
+
+		/* If none of the patterns matched, stop now */
+		if (!matched)
+			return 0;
+	}
+
+	while (o && o->type == OBJ_TAG) {
+		struct tag *t = (struct tag *) o;
+		if (!t->tagged)
+			break; /* broken repository */
+		o = parse_object(the_repository, &t->tagged->oid);
+		deref = 1;
+		taggerdate = t->date;
+	}
+	if (o && o->type == OBJ_COMMIT) {
+		commit = (struct commit *)o;
+		from_tag = starts_with(path, "refs/tags/");
+		if (taggerdate == TIME_MAX)
+			taggerdate = commit->date;
+	}
+
+	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_;
+	return table[ix].oid.hash;
+}
+
+static const char *get_exact_ref_match(const struct object *o)
+{
+	int found;
+
+	if (!tip_table.table || !tip_table.nr)
+		return NULL;
+
+	if (!tip_table.sorted) {
+		QSORT(tip_table.table, tip_table.nr, tipcmp);
+		tip_table.sorted = 1;
+	}
+
+	found = sha1_pos(o->oid.hash, tip_table.table, tip_table.nr,
+			 nth_tip_table_ent);
+	if (0 <= found)
+		return tip_table.table[found].refname;
+	return NULL;
+}
+
+/* may return a constant string or use "buf" as scratch space */
+static const char *get_rev_name(const struct object *o, struct strbuf *buf)
+{
+	struct rev_name *n;
+	const struct commit *c;
+
+	if (o->type != OBJ_COMMIT)
+		return get_exact_ref_match(o);
+	c = (const struct commit *) o;
+	n = get_commit_rev_name(c);
+	if (!n)
+		return NULL;
+
+	if (!n->generation)
+		return n->tip_name;
+	else {
+		strbuf_reset(buf);
+		strbuf_addstr(buf, n->tip_name);
+		strbuf_strip_suffix(buf, "^0");
+		strbuf_addf(buf, "~%d", n->generation);
+		return buf->buf;
+	}
+}
+
+static void show_name(const struct object *obj,
+		      const char *caller_name,
+		      int always, int allow_undefined, int name_only)
+{
+	const char *name;
+	const struct object_id *oid = &obj->oid;
+	struct strbuf buf = STRBUF_INIT;
+
+	if (!name_only)
+		printf("%s ", caller_name ? caller_name : oid_to_hex(oid));
+	name = get_rev_name(obj, &buf);
+	if (name)
+		printf("%s\n", name);
+	else if (allow_undefined)
+		printf("undefined\n");
+	else if (always)
+		printf("%s\n", find_unique_abbrev(oid, DEFAULT_ABBREV));
+	else
+		die("cannot describe '%s'", oid_to_hex(oid));
+	strbuf_release(&buf);
+}
+
+static char const * const name_rev_usage[] = {
+	N_("git name-rev [<options>] <commit>..."),
+	N_("git name-rev [<options>] --all"),
+	N_("git name-rev [<options>] --stdin"),
+	NULL
+};
+
+static void name_rev_line(char *p, struct name_ref_data *data)
+{
+	struct strbuf buf = STRBUF_INIT;
+	int counter = 0;
+	char *p_start;
+	const unsigned hexsz = the_hash_algo->hexsz;
+
+	for (p_start = p; *p; p++) {
+#define ishex(x) (isdigit((x)) || ((x) >= 'a' && (x) <= 'f'))
+		if (!ishex(*p))
+			counter = 0;
+		else if (++counter == hexsz &&
+			 !ishex(*(p+1))) {
+			struct object_id oid;
+			const char *name = NULL;
+			char c = *(p+1);
+			int p_len = p - p_start + 1;
+
+			counter = 0;
+
+			*(p+1) = 0;
+			if (!get_oid(p - (hexsz - 1), &oid)) {
+				struct object *o =
+					lookup_object(the_repository, &oid);
+				if (o)
+					name = get_rev_name(o, &buf);
+			}
+			*(p+1) = c;
+
+			if (!name)
+				continue;
+
+			if (data->name_only)
+				printf("%.*s%s", p_len - hexsz, p_start, name);
+			else
+				printf("%.*s (%s)", p_len, p_start, name);
+			p_start = p + 1;
+		}
+	}
+
+	/* flush */
+	if (p_start != p)
+		fwrite(p_start, p - p_start, 1, stdout);
+
+	strbuf_release(&buf);
+}
+
+int cmd_name_rev(int argc, const char **argv, const char *prefix)
+{
+	struct object_array revs = OBJECT_ARRAY_INIT;
+	int all = 0, transform_stdin = 0, allow_undefined = 1, always = 0, peel_tag = 0;
+	struct name_ref_data data = { 0, 0, STRING_LIST_INIT_NODUP, STRING_LIST_INIT_NODUP };
+	struct option opts[] = {
+		OPT_BOOL(0, "name-only", &data.name_only, N_("print only names (no SHA-1)")),
+		OPT_BOOL(0, "tags", &data.tags_only, N_("only use tags to name the commits")),
+		OPT_STRING_LIST(0, "refs", &data.ref_filters, N_("pattern"),
+				   N_("only use refs matching <pattern>")),
+		OPT_STRING_LIST(0, "exclude", &data.exclude_filters, N_("pattern"),
+				   N_("ignore refs matching <pattern>")),
+		OPT_GROUP(""),
+		OPT_BOOL(0, "all", &all, N_("list all commits reachable from all refs")),
+		OPT_BOOL(0, "stdin", &transform_stdin, N_("read from stdin")),
+		OPT_BOOL(0, "undefined", &allow_undefined, N_("allow to print `undefined` names (default)")),
+		OPT_BOOL(0, "always",     &always,
+			   N_("show abbreviated commit object as fallback")),
+		{
+			/* A Hidden OPT_BOOL */
+			OPTION_SET_INT, 0, "peel-tag", &peel_tag, NULL,
+			N_("dereference tags in the input (internal use)"),
+			PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 1,
+		},
+		OPT_END(),
+	};
+
+	init_commit_rev_name(&rev_names);
+	git_config(git_default_config, NULL);
+	argc = parse_options(argc, argv, prefix, opts, name_rev_usage, 0);
+	if (all + transform_stdin + !!argc > 1) {
+		error("Specify either a list, or --all, not both!");
+		usage_with_options(name_rev_usage, opts);
+	}
+	if (all || transform_stdin)
+		cutoff = 0;
+
+	for (; argc; argc--, argv++) {
+		struct object_id oid;
+		struct object *object;
+		struct commit *commit;
+
+		if (get_oid(*argv, &oid)) {
+			fprintf(stderr, "Could not get sha1 for %s. Skipping.\n",
+					*argv);
+			continue;
+		}
+
+		commit = NULL;
+		object = parse_object(the_repository, &oid);
+		if (object) {
+			struct object *peeled = deref_tag(the_repository,
+							  object, *argv, 0);
+			if (peeled && peeled->type == OBJ_COMMIT)
+				commit = (struct commit *)peeled;
+		}
+
+		if (!object) {
+			fprintf(stderr, "Could not get object for %s. Skipping.\n",
+					*argv);
+			continue;
+		}
+
+		if (commit) {
+			if (cutoff > commit->date)
+				cutoff = commit->date;
+		}
+
+		if (peel_tag) {
+			if (!commit) {
+				fprintf(stderr, "Could not get commit for %s. Skipping.\n",
+					*argv);
+				continue;
+			}
+			object = (struct object *)commit;
+		}
+		add_object_array(object, *argv, &revs);
+	}
+
+	if (cutoff) {
+		/* check for undeflow */
+		if (cutoff > TIME_MIN + CUTOFF_DATE_SLOP)
+			cutoff = cutoff - CUTOFF_DATE_SLOP;
+		else
+			cutoff = TIME_MIN;
+	}
+	for_each_ref(name_ref, &data);
+	name_tips();
+
+	if (transform_stdin) {
+		char buffer[2048];
+
+		while (!feof(stdin)) {
+			char *p = fgets(buffer, sizeof(buffer), stdin);
+			if (!p)
+				break;
+			name_rev_line(p, &data);
+		}
+	} else if (all) {
+		int i, max;
+
+		max = get_max_object_index();
+		for (i = 0; i < max; i++) {
+			struct object *obj = get_indexed_object(i);
+			if (!obj || obj->type != OBJ_COMMIT)
+				continue;
+			show_name(obj, NULL,
+				  always, allow_undefined, data.name_only);
+		}
+	} else {
+		int i;
+		for (i = 0; i < revs.nr; i++)
+			show_name(revs.objects[i].item, revs.objects[i].name,
+				  always, allow_undefined, data.name_only);
+	}
+
+	UNLEAK(revs);
+	return 0;
+}