1 files changed, 305 insertions, 0 deletions

diff --git a/builtin/name-rev.c b/builtin/name-rev.c
new file mode 100644
index 000000000..06a38ac8c
--- /dev/null
+++ b/builtin/name-rev.c
@@ -0,0 +1,305 @@
+#include "builtin.h"
+#include "cache.h"
+#include "commit.h"
+#include "tag.h"
+#include "refs.h"
+#include "parse-options.h"
+
+#define CUTOFF_DATE_SLOP 86400 /* one day */
+
+typedef struct rev_name {
+	const char *tip_name;
+	int generation;
+	int distance;
+} rev_name;
+
+static long cutoff = LONG_MAX;
+
+/* How many generations are maximally preferred over _one_ merge traversal? */
+#define MERGE_TRAVERSAL_WEIGHT 65535
+
+static void name_rev(struct commit *commit,
+		const char *tip_name, int generation, int distance,
+		int deref)
+{
+	struct rev_name *name = (struct rev_name *)commit->util;
+	struct commit_list *parents;
+	int parent_number = 1;
+
+	if (!commit->object.parsed)
+		parse_commit(commit);
+
+	if (commit->date < cutoff)
+		return;
+
+	if (deref) {
+		char *new_name = xmalloc(strlen(tip_name)+3);
+		strcpy(new_name, tip_name);
+		strcat(new_name, "^0");
+		tip_name = new_name;
+
+		if (generation)
+			die("generation: %d, but deref?", generation);
+	}
+
+	if (name == NULL) {
+		name = xmalloc(sizeof(rev_name));
+		commit->util = name;
+		goto copy_data;
+	} else if (name->distance > distance) {
+copy_data:
+		name->tip_name = tip_name;
+		name->generation = generation;
+		name->distance = distance;
+	} else
+		return;
+
+	for (parents = commit->parents;
+			parents;
+			parents = parents->next, parent_number++) {
+		if (parent_number > 1) {
+			int len = strlen(tip_name);
+			char *new_name = xmalloc(len +
+				1 + decimal_length(generation) +  /* ~<n> */
+				1 + 2 +				  /* ^NN */
+				1);
+
+			if (len > 2 && !strcmp(tip_name + len - 2, "^0"))
+				len -= 2;
+			if (generation > 0)
+				sprintf(new_name, "%.*s~%d^%d", len, tip_name,
+						generation, parent_number);
+			else
+				sprintf(new_name, "%.*s^%d", len, tip_name,
+						parent_number);
+
+			name_rev(parents->item, new_name, 0,
+				distance + MERGE_TRAVERSAL_WEIGHT, 0);
+		} else {
+			name_rev(parents->item, tip_name, generation + 1,
+				distance + 1, 0);
+		}
+	}
+}
+
+struct name_ref_data {
+	int tags_only;
+	int name_only;
+	const char *ref_filter;
+};
+
+static int name_ref(const char *path, const unsigned char *sha1, int flags, void *cb_data)
+{
+	struct object *o = parse_object(sha1);
+	struct name_ref_data *data = cb_data;
+	int deref = 0;
+
+	if (data->tags_only && prefixcmp(path, "refs/tags/"))
+		return 0;
+
+	if (data->ref_filter && fnmatch(data->ref_filter, path, 0))
+		return 0;
+
+	while (o && o->type == OBJ_TAG) {
+		struct tag *t = (struct tag *) o;
+		if (!t->tagged)
+			break; /* broken repository */
+		o = parse_object(t->tagged->sha1);
+		deref = 1;
+	}
+	if (o && o->type == OBJ_COMMIT) {
+		struct commit *commit = (struct commit *)o;
+
+		if (!prefixcmp(path, "refs/heads/"))
+			path = path + 11;
+		else if (data->tags_only
+		    && data->name_only
+		    && !prefixcmp(path, "refs/tags/"))
+			path = path + 10;
+		else if (!prefixcmp(path, "refs/"))
+			path = path + 5;
+
+		name_rev(commit, xstrdup(path), 0, 0, deref);
+	}
+	return 0;
+}
+
+/* returns a static buffer */
+static const char *get_rev_name(const struct object *o)
+{
+	static char buffer[1024];
+	struct rev_name *n;
+	struct commit *c;
+
+	if (o->type != OBJ_COMMIT)
+		return NULL;
+	c = (struct commit *) o;
+	n = c->util;
+	if (!n)
+		return NULL;
+
+	if (!n->generation)
+		return n->tip_name;
+	else {
+		int len = strlen(n->tip_name);
+		if (len > 2 && !strcmp(n->tip_name + len - 2, "^0"))
+			len -= 2;
+		snprintf(buffer, sizeof(buffer), "%.*s~%d", len, n->tip_name,
+				n->generation);
+
+		return buffer;
+	}
+}
+
+static void show_name(const struct object *obj,
+		      const char *caller_name,
+		      int always, int allow_undefined, int name_only)
+{
+	const char *name;
+	const unsigned char *sha1 = obj->sha1;
+
+	if (!name_only)
+		printf("%s ", caller_name ? caller_name : sha1_to_hex(sha1));
+	name = get_rev_name(obj);
+	if (name)
+		printf("%s\n", name);
+	else if (allow_undefined)
+		printf("undefined\n");
+	else if (always)
+		printf("%s\n", find_unique_abbrev(sha1, DEFAULT_ABBREV));
+	else
+		die("cannot describe '%s'", sha1_to_hex(sha1));
+}
+
+static char const * const name_rev_usage[] = {
+	"git name-rev [options] ( --all | --stdin | <commit>... )",
+	NULL
+};
+
+static void name_rev_line(char *p, struct name_ref_data *data)
+{
+	int forty = 0;
+	char *p_start;
+	for (p_start = p; *p; p++) {
+#define ishex(x) (isdigit((x)) || ((x) >= 'a' && (x) <= 'f'))
+		if (!ishex(*p))
+			forty = 0;
+		else if (++forty == 40 &&
+			 !ishex(*(p+1))) {
+			unsigned char sha1[40];
+			const char *name = NULL;
+			char c = *(p+1);
+			int p_len = p - p_start + 1;
+
+			forty = 0;
+
+			*(p+1) = 0;
+			if (!get_sha1(p - 39, sha1)) {
+				struct object *o =
+					lookup_object(sha1);
+				if (o)
+					name = get_rev_name(o);
+			}
+			*(p+1) = c;
+
+			if (!name)
+				continue;
+
+			if (data->name_only)
+				printf("%.*s%s", p_len - 40, 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);
+}
+
+int cmd_name_rev(int argc, const char **argv, const char *prefix)
+{
+	struct object_array revs = { 0, 0, NULL };
+	int all = 0, transform_stdin = 0, allow_undefined = 1, always = 0;
+	struct name_ref_data data = { 0, 0, NULL };
+	struct option opts[] = {
+		OPT_BOOLEAN(0, "name-only", &data.name_only, "print only names (no SHA-1)"),
+		OPT_BOOLEAN(0, "tags", &data.tags_only, "only use tags to name the commits"),
+		OPT_STRING(0, "refs", &data.ref_filter, "pattern",
+				   "only use refs matching <pattern>"),
+		OPT_GROUP(""),
+		OPT_BOOLEAN(0, "all", &all, "list all commits reachable from all refs"),
+		OPT_BOOLEAN(0, "stdin", &transform_stdin, "read from stdin"),
+		OPT_BOOLEAN(0, "undefined", &allow_undefined, "allow to print `undefined` names"),
+		OPT_BOOLEAN(0, "always",     &always,
+			   "show abbreviated commit object as fallback"),
+		OPT_END(),
+	};
+
+	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++) {
+		unsigned char sha1[20];
+		struct object *o;
+		struct commit *commit;
+
+		if (get_sha1(*argv, sha1)) {
+			fprintf(stderr, "Could not get sha1 for %s. Skipping.\n",
+					*argv);
+			continue;
+		}
+
+		o = deref_tag(parse_object(sha1), *argv, 0);
+		if (!o || o->type != OBJ_COMMIT) {
+			fprintf(stderr, "Could not get commit for %s. Skipping.\n",
+					*argv);
+			continue;
+		}
+
+		commit = (struct commit *)o;
+		if (cutoff > commit->date)
+			cutoff = commit->date;
+		add_object_array((struct object *)commit, *argv, &revs);
+	}
+
+	if (cutoff)
+		cutoff = cutoff - CUTOFF_DATE_SLOP;
+	for_each_ref(name_ref, &data);
+
+	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)
+				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);
+	}
+
+	return 0;
+}