Builtin git-show-branch.

Signed-off-by: Peter Eriksen <s022018@student.dtu.dk>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 789 insertions, 0 deletions

diff --git a/builtin-show-branch.c b/builtin-show-branch.c
new file mode 100644
index 000000000..3af24e767
--- /dev/null
+++ b/builtin-show-branch.c
@@ -0,0 +1,789 @@
+#include <stdlib.h>
+#include <fnmatch.h>
+#include "cache.h"
+#include "commit.h"
+#include "refs.h"
+#include "builtin.h"
+
+static const char show_branch_usage[] =
+"git-show-branch [--dense] [--current] [--all] [--heads] [--tags] [--topo-order] [--more=count | --list | --independent | --merge-base ] [--topics] [<refs>...]";
+
+static int default_num = 0;
+static int default_alloc = 0;
+static const char **default_arg = NULL;
+
+#define UNINTERESTING	01
+
+#define REV_SHIFT	 2
+#define MAX_REVS	29 /* should not exceed bits_per_int - REV_SHIFT */
+
+static struct commit *interesting(struct commit_list *list)
+{
+	while (list) {
+		struct commit *commit = list->item;
+		list = list->next;
+		if (commit->object.flags & UNINTERESTING)
+			continue;
+		return commit;
+	}
+	return NULL;
+}
+
+static struct commit *pop_one_commit(struct commit_list **list_p)
+{
+	struct commit *commit;
+	struct commit_list *list;
+	list = *list_p;
+	commit = list->item;
+	*list_p = list->next;
+	free(list);
+	return commit;
+}
+
+struct commit_name {
+	const char *head_name; /* which head's ancestor? */
+	int generation; /* how many parents away from head_name */
+};
+
+/* Name the commit as nth generation ancestor of head_name;
+ * we count only the first-parent relationship for naming purposes.
+ */
+static void name_commit(struct commit *commit, const char *head_name, int nth)
+{
+	struct commit_name *name;
+	if (!commit->object.util)
+		commit->object.util = xmalloc(sizeof(struct commit_name));
+	name = commit->object.util;
+	name->head_name = head_name;
+	name->generation = nth;
+}
+
+/* Parent is the first parent of the commit.  We may name it
+ * as (n+1)th generation ancestor of the same head_name as
+ * commit is nth generation ancestor of, if that generation
+ * number is better than the name it already has.
+ */
+static void name_parent(struct commit *commit, struct commit *parent)
+{
+	struct commit_name *commit_name = commit->object.util;
+	struct commit_name *parent_name = parent->object.util;
+	if (!commit_name)
+		return;
+	if (!parent_name ||
+	    commit_name->generation + 1 < parent_name->generation)
+		name_commit(parent, commit_name->head_name,
+			    commit_name->generation + 1);
+}
+
+static int name_first_parent_chain(struct commit *c)
+{
+	int i = 0;
+	while (c) {
+		struct commit *p;
+		if (!c->object.util)
+			break;
+		if (!c->parents)
+			break;
+		p = c->parents->item;
+		if (!p->object.util) {
+			name_parent(c, p);
+			i++;
+		}
+		c = p;
+	}
+	return i;
+}
+
+static void name_commits(struct commit_list *list,
+			 struct commit **rev,
+			 char **ref_name,
+			 int num_rev)
+{
+	struct commit_list *cl;
+	struct commit *c;
+	int i;
+
+	/* First give names to the given heads */
+	for (cl = list; cl; cl = cl->next) {
+		c = cl->item;
+		if (c->object.util)
+			continue;
+		for (i = 0; i < num_rev; i++) {
+			if (rev[i] == c) {
+				name_commit(c, ref_name[i], 0);
+				break;
+			}
+		}
+	}
+
+	/* Then commits on the first parent ancestry chain */
+	do {
+		i = 0;
+		for (cl = list; cl; cl = cl->next) {
+			i += name_first_parent_chain(cl->item);
+		}
+	} while (i);
+
+	/* Finally, any unnamed commits */
+	do {
+		i = 0;
+		for (cl = list; cl; cl = cl->next) {
+			struct commit_list *parents;
+			struct commit_name *n;
+			int nth;
+			c = cl->item;
+			if (!c->object.util)
+				continue;
+			n = c->object.util;
+			parents = c->parents;
+			nth = 0;
+			while (parents) {
+				struct commit *p = parents->item;
+				char newname[1000], *en;
+				parents = parents->next;
+				nth++;
+				if (p->object.util)
+					continue;
+				en = newname;
+				switch (n->generation) {
+				case 0:
+					en += sprintf(en, "%s", n->head_name);
+					break;
+				case 1:
+					en += sprintf(en, "%s^", n->head_name);
+					break;
+				default:
+					en += sprintf(en, "%s~%d",
+						n->head_name, n->generation);
+					break;
+				}
+				if (nth == 1)
+					en += sprintf(en, "^");
+				else
+					en += sprintf(en, "^%d", nth);
+				name_commit(p, strdup(newname), 0);
+				i++;
+				name_first_parent_chain(p);
+			}
+		}
+	} while (i);
+}
+
+static int mark_seen(struct commit *commit, struct commit_list **seen_p)
+{
+	if (!commit->object.flags) {
+		insert_by_date(commit, seen_p);
+		return 1;
+	}
+	return 0;
+}
+
+static void join_revs(struct commit_list **list_p,
+		      struct commit_list **seen_p,
+		      int num_rev, int extra)
+{
+	int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
+	int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
+
+	while (*list_p) {
+		struct commit_list *parents;
+		int still_interesting = !!interesting(*list_p);
+		struct commit *commit = pop_one_commit(list_p);
+		int flags = commit->object.flags & all_mask;
+
+		if (!still_interesting && extra <= 0)
+			break;
+
+		mark_seen(commit, seen_p);
+		if ((flags & all_revs) == all_revs)
+			flags |= UNINTERESTING;
+		parents = commit->parents;
+
+		while (parents) {
+			struct commit *p = parents->item;
+			int this_flag = p->object.flags;
+			parents = parents->next;
+			if ((this_flag & flags) == flags)
+				continue;
+			if (!p->object.parsed)
+				parse_commit(p);
+			if (mark_seen(p, seen_p) && !still_interesting)
+				extra--;
+			p->object.flags |= flags;
+			insert_by_date(p, list_p);
+		}
+	}
+
+	/*
+	 * Postprocess to complete well-poisoning.
+	 *
+	 * At this point we have all the commits we have seen in
+	 * seen_p list (which happens to be sorted chronologically but
+	 * it does not really matter).  Mark anything that can be
+	 * reached from uninteresting commits not interesting.
+	 */
+	for (;;) {
+		int changed = 0;
+		struct commit_list *s;
+		for (s = *seen_p; s; s = s->next) {
+			struct commit *c = s->item;
+			struct commit_list *parents;
+
+			if (((c->object.flags & all_revs) != all_revs) &&
+			    !(c->object.flags & UNINTERESTING))
+				continue;
+
+			/* The current commit is either a merge base or
+			 * already uninteresting one.  Mark its parents
+			 * as uninteresting commits _only_ if they are
+			 * already parsed.  No reason to find new ones
+			 * here.
+			 */
+			parents = c->parents;
+			while (parents) {
+				struct commit *p = parents->item;
+				parents = parents->next;
+				if (!(p->object.flags & UNINTERESTING)) {
+					p->object.flags |= UNINTERESTING;
+					changed = 1;
+				}
+			}
+		}
+		if (!changed)
+			break;
+	}
+}
+
+static void show_one_commit(struct commit *commit, int no_name)
+{
+	char pretty[256], *cp;
+	struct commit_name *name = commit->object.util;
+	if (commit->object.parsed)
+		pretty_print_commit(CMIT_FMT_ONELINE, commit, ~0,
+				    pretty, sizeof(pretty), 0);
+	else
+		strcpy(pretty, "(unavailable)");
+	if (!strncmp(pretty, "[PATCH] ", 8))
+		cp = pretty + 8;
+	else
+		cp = pretty;
+
+	if (!no_name) {
+		if (name && name->head_name) {
+			printf("[%s", name->head_name);
+			if (name->generation) {
+				if (name->generation == 1)
+					printf("^");
+				else
+					printf("~%d", name->generation);
+			}
+			printf("] ");
+		}
+		else
+			printf("[%s] ",
+			       find_unique_abbrev(commit->object.sha1, 7));
+	}
+	puts(cp);
+}
+
+static char *ref_name[MAX_REVS + 1];
+static int ref_name_cnt;
+
+static const char *find_digit_prefix(const char *s, int *v)
+{
+	const char *p;
+	int ver;
+	char ch;
+
+	for (p = s, ver = 0;
+	     '0' <= (ch = *p) && ch <= '9';
+	     p++)
+		ver = ver * 10 + ch - '0';
+	*v = ver;
+	return p;
+}
+
+
+static int version_cmp(const char *a, const char *b)
+{
+	while (1) {
+		int va, vb;
+
+		a = find_digit_prefix(a, &va);
+		b = find_digit_prefix(b, &vb);
+		if (va != vb)
+			return va - vb;
+
+		while (1) {
+			int ca = *a;
+			int cb = *b;
+			if ('0' <= ca && ca <= '9')
+				ca = 0;
+			if ('0' <= cb && cb <= '9')
+				cb = 0;
+			if (ca != cb)
+				return ca - cb;
+			if (!ca)
+				break;
+			a++;
+			b++;
+		}
+		if (!*a && !*b)
+			return 0;
+	}
+}
+
+static int compare_ref_name(const void *a_, const void *b_)
+{
+	const char * const*a = a_, * const*b = b_;
+	return version_cmp(*a, *b);
+}
+
+static void sort_ref_range(int bottom, int top)
+{
+	qsort(ref_name + bottom, top - bottom, sizeof(ref_name[0]),
+	      compare_ref_name);
+}
+
+static int append_ref(const char *refname, const unsigned char *sha1)
+{
+	struct commit *commit = lookup_commit_reference_gently(sha1, 1);
+	int i;
+
+	if (!commit)
+		return 0;
+	/* Avoid adding the same thing twice */
+	for (i = 0; i < ref_name_cnt; i++)
+		if (!strcmp(refname, ref_name[i]))
+			return 0;
+
+	if (MAX_REVS <= ref_name_cnt) {
+		fprintf(stderr, "warning: ignoring %s; "
+			"cannot handle more than %d refs\n",
+			refname, MAX_REVS);
+		return 0;
+	}
+	ref_name[ref_name_cnt++] = strdup(refname);
+	ref_name[ref_name_cnt] = NULL;
+	return 0;
+}
+
+static int append_head_ref(const char *refname, const unsigned char *sha1)
+{
+	unsigned char tmp[20];
+	int ofs = 11;
+	if (strncmp(refname, "refs/heads/", ofs))
+		return 0;
+	/* If both heads/foo and tags/foo exists, get_sha1 would
+	 * get confused.
+	 */
+	if (get_sha1(refname + ofs, tmp) || memcmp(tmp, sha1, 20))
+		ofs = 5;
+	return append_ref(refname + ofs, sha1);
+}
+
+static int append_tag_ref(const char *refname, const unsigned char *sha1)
+{
+	if (strncmp(refname, "refs/tags/", 10))
+		return 0;
+	return append_ref(refname + 5, sha1);
+}
+
+static const char *match_ref_pattern = NULL;
+static int match_ref_slash = 0;
+static int count_slash(const char *s)
+{
+	int cnt = 0;
+	while (*s)
+		if (*s++ == '/')
+			cnt++;
+	return cnt;
+}
+
+static int append_matching_ref(const char *refname, const unsigned char *sha1)
+{
+	/* we want to allow pattern hold/<asterisk> to show all
+	 * branches under refs/heads/hold/, and v0.99.9? to show
+	 * refs/tags/v0.99.9a and friends.
+	 */
+	const char *tail;
+	int slash = count_slash(refname);
+	for (tail = refname; *tail && match_ref_slash < slash; )
+		if (*tail++ == '/')
+			slash--;
+	if (!*tail)
+		return 0;
+	if (fnmatch(match_ref_pattern, tail, 0))
+		return 0;
+	if (!strncmp("refs/heads/", refname, 11))
+		return append_head_ref(refname, sha1);
+	if (!strncmp("refs/tags/", refname, 10))
+		return append_tag_ref(refname, sha1);
+	return append_ref(refname, sha1);
+}
+
+static void snarf_refs(int head, int tag)
+{
+	if (head) {
+		int orig_cnt = ref_name_cnt;
+		for_each_ref(append_head_ref);
+		sort_ref_range(orig_cnt, ref_name_cnt);
+	}
+	if (tag) {
+		int orig_cnt = ref_name_cnt;
+		for_each_ref(append_tag_ref);
+		sort_ref_range(orig_cnt, ref_name_cnt);
+	}
+}
+
+static int rev_is_head(char *head_path, int headlen, char *name,
+		       unsigned char *head_sha1, unsigned char *sha1)
+{
+	int namelen;
+	if ((!head_path[0]) ||
+	    (head_sha1 && sha1 && memcmp(head_sha1, sha1, 20)))
+		return 0;
+	namelen = strlen(name);
+	if ((headlen < namelen) ||
+	    memcmp(head_path + headlen - namelen, name, namelen))
+		return 0;
+	if (headlen == namelen ||
+	    head_path[headlen - namelen - 1] == '/')
+		return 1;
+	return 0;
+}
+
+static int show_merge_base(struct commit_list *seen, int num_rev)
+{
+	int all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
+	int all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
+	int exit_status = 1;
+
+	while (seen) {
+		struct commit *commit = pop_one_commit(&seen);
+		int flags = commit->object.flags & all_mask;
+		if (!(flags & UNINTERESTING) &&
+		    ((flags & all_revs) == all_revs)) {
+			puts(sha1_to_hex(commit->object.sha1));
+			exit_status = 0;
+			commit->object.flags |= UNINTERESTING;
+		}
+	}
+	return exit_status;
+}
+
+static int show_independent(struct commit **rev,
+			    int num_rev,
+			    char **ref_name,
+			    unsigned int *rev_mask)
+{
+	int i;
+
+	for (i = 0; i < num_rev; i++) {
+		struct commit *commit = rev[i];
+		unsigned int flag = rev_mask[i];
+
+		if (commit->object.flags == flag)
+			puts(sha1_to_hex(commit->object.sha1));
+		commit->object.flags |= UNINTERESTING;
+	}
+	return 0;
+}
+
+static void append_one_rev(const char *av)
+{
+	unsigned char revkey[20];
+	if (!get_sha1(av, revkey)) {
+		append_ref(av, revkey);
+		return;
+	}
+	if (strchr(av, '*') || strchr(av, '?') || strchr(av, '[')) {
+		/* glob style match */
+		int saved_matches = ref_name_cnt;
+		match_ref_pattern = av;
+		match_ref_slash = count_slash(av);
+		for_each_ref(append_matching_ref);
+		if (saved_matches == ref_name_cnt &&
+		    ref_name_cnt < MAX_REVS)
+			error("no matching refs with %s", av);
+		if (saved_matches + 1 < ref_name_cnt)
+			sort_ref_range(saved_matches, ref_name_cnt);
+		return;
+	}
+	die("bad sha1 reference %s", av);
+}
+
+static int git_show_branch_config(const char *var, const char *value)
+{
+	if (!strcmp(var, "showbranch.default")) {
+		if (default_alloc <= default_num + 1) {
+			default_alloc = default_alloc * 3 / 2 + 20;
+			default_arg = xrealloc(default_arg, sizeof *default_arg * default_alloc);
+		}
+		default_arg[default_num++] = strdup(value);
+		default_arg[default_num] = NULL;
+		return 0;
+	}
+
+	return git_default_config(var, value);
+}
+
+static int omit_in_dense(struct commit *commit, struct commit **rev, int n)
+{
+	/* If the commit is tip of the named branches, do not
+	 * omit it.
+	 * Otherwise, if it is a merge that is reachable from only one
+	 * tip, it is not that interesting.
+	 */
+	int i, flag, count;
+	for (i = 0; i < n; i++)
+		if (rev[i] == commit)
+			return 0;
+	flag = commit->object.flags;
+	for (i = count = 0; i < n; i++) {
+		if (flag & (1u << (i + REV_SHIFT)))
+			count++;
+	}
+	if (count == 1)
+		return 1;
+	return 0;
+}
+
+int cmd_show_branch(int ac, const char **av, char **envp)
+{
+	struct commit *rev[MAX_REVS], *commit;
+	struct commit_list *list = NULL, *seen = NULL;
+	unsigned int rev_mask[MAX_REVS];
+	int num_rev, i, extra = 0;
+	int all_heads = 0, all_tags = 0;
+	int all_mask, all_revs;
+	int lifo = 1;
+	char head_path[128];
+	const char *head_path_p;
+	int head_path_len;
+	unsigned char head_sha1[20];
+	int merge_base = 0;
+	int independent = 0;
+	int no_name = 0;
+	int sha1_name = 0;
+	int shown_merge_point = 0;
+	int with_current_branch = 0;
+	int head_at = -1;
+	int topics = 0;
+	int dense = 1;
+
+	setup_git_directory();
+	git_config(git_show_branch_config);
+
+	/* If nothing is specified, try the default first */
+	if (ac == 1 && default_num) {
+		ac = default_num + 1;
+		av = default_arg - 1; /* ick; we would not address av[0] */
+	}
+
+	while (1 < ac && av[1][0] == '-') {
+		const char *arg = av[1];
+		if (!strcmp(arg, "--")) {
+			ac--; av++;
+			break;
+		}
+		else if (!strcmp(arg, "--all"))
+			all_heads = all_tags = 1;
+		else if (!strcmp(arg, "--heads"))
+			all_heads = 1;
+		else if (!strcmp(arg, "--tags"))
+			all_tags = 1;
+		else if (!strcmp(arg, "--more"))
+			extra = 1;
+		else if (!strcmp(arg, "--list"))
+			extra = -1;
+		else if (!strcmp(arg, "--no-name"))
+			no_name = 1;
+		else if (!strcmp(arg, "--current"))
+			with_current_branch = 1;
+		else if (!strcmp(arg, "--sha1-name"))
+			sha1_name = 1;
+		else if (!strncmp(arg, "--more=", 7))
+			extra = atoi(arg + 7);
+		else if (!strcmp(arg, "--merge-base"))
+			merge_base = 1;
+		else if (!strcmp(arg, "--independent"))
+			independent = 1;
+		else if (!strcmp(arg, "--topo-order"))
+			lifo = 1;
+		else if (!strcmp(arg, "--topics"))
+			topics = 1;
+		else if (!strcmp(arg, "--sparse"))
+			dense = 0;
+		else if (!strcmp(arg, "--date-order"))
+			lifo = 0;
+		else
+			usage(show_branch_usage);
+		ac--; av++;
+	}
+	ac--; av++;
+
+	/* Only one of these is allowed */
+	if (1 < independent + merge_base + (extra != 0))
+		usage(show_branch_usage);
+
+	/* If nothing is specified, show all branches by default */
+	if (ac + all_heads + all_tags == 0)
+		all_heads = 1;
+
+	if (all_heads + all_tags)
+		snarf_refs(all_heads, all_tags);
+	while (0 < ac) {
+		append_one_rev(*av);
+		ac--; av++;
+	}
+
+	head_path_p = resolve_ref(git_path("HEAD"), head_sha1, 1);
+	if (head_path_p) {
+		head_path_len = strlen(head_path_p);
+		memcpy(head_path, head_path_p, head_path_len + 1);
+	}
+	else {
+		head_path_len = 0;
+		head_path[0] = 0;
+	}
+
+	if (with_current_branch && head_path_p) {
+		int has_head = 0;
+		for (i = 0; !has_head && i < ref_name_cnt; i++) {
+			/* We are only interested in adding the branch
+			 * HEAD points at.
+			 */
+			if (rev_is_head(head_path,
+					head_path_len,
+					ref_name[i],
+					head_sha1, NULL))
+				has_head++;
+		}
+		if (!has_head) {
+			int pfxlen = strlen(git_path("refs/heads/"));
+			append_one_rev(head_path + pfxlen);
+		}
+	}
+
+	if (!ref_name_cnt) {
+		fprintf(stderr, "No revs to be shown.\n");
+		exit(0);
+	}
+
+	for (num_rev = 0; ref_name[num_rev]; num_rev++) {
+		unsigned char revkey[20];
+		unsigned int flag = 1u << (num_rev + REV_SHIFT);
+
+		if (MAX_REVS <= num_rev)
+			die("cannot handle more than %d revs.", MAX_REVS);
+		if (get_sha1(ref_name[num_rev], revkey))
+			die("'%s' is not a valid ref.", ref_name[num_rev]);
+		commit = lookup_commit_reference(revkey);
+		if (!commit)
+			die("cannot find commit %s (%s)",
+			    ref_name[num_rev], revkey);
+		parse_commit(commit);
+		mark_seen(commit, &seen);
+
+		/* rev#0 uses bit REV_SHIFT, rev#1 uses bit REV_SHIFT+1,
+		 * and so on.  REV_SHIFT bits from bit 0 are used for
+		 * internal bookkeeping.
+		 */
+		commit->object.flags |= flag;
+		if (commit->object.flags == flag)
+			insert_by_date(commit, &list);
+		rev[num_rev] = commit;
+	}
+	for (i = 0; i < num_rev; i++)
+		rev_mask[i] = rev[i]->object.flags;
+
+	if (0 <= extra)
+		join_revs(&list, &seen, num_rev, extra);
+
+	if (merge_base)
+		return show_merge_base(seen, num_rev);
+
+	if (independent)
+		return show_independent(rev, num_rev, ref_name, rev_mask);
+
+	/* Show list; --more=-1 means list-only */
+	if (1 < num_rev || extra < 0) {
+		for (i = 0; i < num_rev; i++) {
+			int j;
+			int is_head = rev_is_head(head_path,
+						  head_path_len,
+						  ref_name[i],
+						  head_sha1,
+						  rev[i]->object.sha1);
+			if (extra < 0)
+				printf("%c [%s] ",
+				       is_head ? '*' : ' ', ref_name[i]);
+			else {
+				for (j = 0; j < i; j++)
+					putchar(' ');
+				printf("%c [%s] ",
+				       is_head ? '*' : '!', ref_name[i]);
+			}
+			/* header lines never need name */
+			show_one_commit(rev[i], 1);
+			if (is_head)
+				head_at = i;
+		}
+		if (0 <= extra) {
+			for (i = 0; i < num_rev; i++)
+				putchar('-');
+			putchar('\n');
+		}
+	}
+	if (extra < 0)
+		exit(0);
+
+	/* Sort topologically */
+	sort_in_topological_order(&seen, lifo);
+
+	/* Give names to commits */
+	if (!sha1_name && !no_name)
+		name_commits(seen, rev, ref_name, num_rev);
+
+	all_mask = ((1u << (REV_SHIFT + num_rev)) - 1);
+	all_revs = all_mask & ~((1u << REV_SHIFT) - 1);
+
+	while (seen) {
+		struct commit *commit = pop_one_commit(&seen);
+		int this_flag = commit->object.flags;
+		int is_merge_point = ((this_flag & all_revs) == all_revs);
+
+		shown_merge_point |= is_merge_point;
+
+		if (1 < num_rev) {
+			int is_merge = !!(commit->parents &&
+					  commit->parents->next);
+			if (topics &&
+			    !is_merge_point &&
+			    (this_flag & (1u << REV_SHIFT)))
+				continue;
+			if (dense && is_merge &&
+			    omit_in_dense(commit, rev, num_rev))
+				continue;
+			for (i = 0; i < num_rev; i++) {
+				int mark;
+				if (!(this_flag & (1u << (i + REV_SHIFT))))
+					mark = ' ';
+				else if (is_merge)
+					mark = '-';
+				else if (i == head_at)
+					mark = '*';
+				else
+					mark = '+';
+				putchar(mark);
+			}
+			putchar(' ');
+		}
+		show_one_commit(commit, no_name);
+
+		if (shown_merge_point && --extra < 0)
+			break;
+	}
+	return 0;
+}