git-fetch--tool: start rewriting parts of git-fetch in C.

Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 214 insertions, 0 deletions

diff --git a/builtin-fetch--tool.c b/builtin-fetch--tool.c
new file mode 100644
index 000000000..3075ba04a
--- /dev/null
+++ b/builtin-fetch--tool.c
@@ -0,0 +1,214 @@
+#include "cache.h"
+#include "refs.h"
+#include "commit.h"
+
+static void show_new(char *type, unsigned char *sha1_new)
+{
+	fprintf(stderr, "  %s: %s\n", type,
+		find_unique_abbrev(sha1_new, DEFAULT_ABBREV));
+}
+
+static int update_ref(const char *action,
+		      const char *refname,
+		      unsigned char *sha1,
+		      unsigned char *oldval)
+{
+	int len;
+	char msg[1024];
+	char *rla = getenv("GIT_REFLOG_ACTION");
+	static struct ref_lock *lock;
+
+	if (!rla)
+		rla = "(reflog update)";
+	len = snprintf(msg, sizeof(msg), "%s: %s", rla, action);
+	if (sizeof(msg) <= len)
+		die("insanely long action");
+	lock = lock_any_ref_for_update(refname, oldval);
+	if (!lock)
+		return 1;
+	if (write_ref_sha1(lock, sha1, msg) < 0)
+		return 1;
+	return 0;
+}
+
+static int update_local_ref(const char *name,
+			    const char *new_head,
+			    const char *note,
+			    int verbose, int force)
+{
+	char type[20];
+	unsigned char sha1_old[20], sha1_new[20];
+	char oldh[41], newh[41];
+	struct commit *current, *updated;
+
+	if (get_sha1_hex(new_head, sha1_new))
+		die("malformed object name %s", new_head);
+	if (sha1_object_info(sha1_new, type, NULL))
+		die("object %s not found", new_head);
+
+	if (!*name) {
+		/* Not storing */
+		if (verbose) {
+			fprintf(stderr, "* fetched %s\n", note);
+			show_new(type, sha1_new);
+		}
+		return 0;
+	}
+
+	if (get_sha1(name, sha1_old)) {
+		char *msg;
+	just_store:
+		/* new ref */
+		if (!strncmp(name, "refs/tags/", 10))
+			msg = "storing tag";
+		else
+			msg = "storing head";
+		fprintf(stderr, "* %s: storing %s\n",
+			name, note);
+		show_new(type, sha1_new);
+		return update_ref(msg, name, sha1_new, NULL);
+	}
+
+	if (!hashcmp(sha1_old, sha1_new)) {
+		if (verbose) {
+			fprintf(stderr, "* %s: same as %s\n", name, note);
+			show_new(type, sha1_new);
+		}
+		return 0;
+	}
+
+	if (!strncmp(name, "refs/tags/", 10)) {
+		fprintf(stderr, "* %s: updating with %s\n", name, note);
+		show_new(type, sha1_new);
+		return update_ref("updating tag", name, sha1_new, NULL);
+	}
+
+	current = lookup_commit_reference(sha1_old);
+	updated = lookup_commit_reference(sha1_new);
+	if (!current || !updated)
+		goto just_store;
+
+	strcpy(oldh, find_unique_abbrev(current->object.sha1, DEFAULT_ABBREV));
+	strcpy(newh, find_unique_abbrev(sha1_new, DEFAULT_ABBREV));
+
+	if (in_merge_bases(current, &updated, 1)) {
+		fprintf(stderr, "* %s: fast forward to %s\n",
+			name, note);
+		fprintf(stderr, "  old..new: %s..%s\n", oldh, newh);
+		return update_ref("fast forward", name, sha1_new, sha1_old);
+	}
+	if (!force) {
+		fprintf(stderr,
+			"* %s: not updating to non-fast forward %s\n",
+			name, note);
+		fprintf(stderr,
+			"  old...new: %s...%s\n", oldh, newh);
+		return 1;
+	}
+	fprintf(stderr,
+		"* %s: forcing update to non-fast forward %s\n",
+		name, note);
+	fprintf(stderr, "  old...new: %s...%s\n", oldh, newh);
+	return update_ref("forced-update", name, sha1_new, sha1_old);
+}
+
+static int append_fetch_head(FILE *fp,
+			     const char *head, const char *remote,
+			     const char *remote_name, const char *remote_nick,
+			     const char *local_name, int not_for_merge,
+			     int verbose, int force)
+{
+	struct commit *commit;
+	int remote_len, i, note_len;
+	unsigned char sha1[20];
+	char note[1024];
+	const char *what, *kind;
+
+	if (get_sha1(head, sha1))
+		return error("Not a valid object name: %s", head);
+	commit = lookup_commit_reference(sha1);
+	if (!commit)
+		not_for_merge = 1;
+
+	if (!strcmp(remote_name, "HEAD")) {
+		kind = "";
+		what = "";
+	}
+	else if (!strncmp(remote_name, "refs/heads/", 11)) {
+		kind = "branch";
+		what = remote_name + 11;
+	}
+	else if (!strncmp(remote_name, "refs/tags/", 10)) {
+		kind = "tag";
+		what = remote_name + 10;
+	}
+	else if (!strncmp(remote_name, "refs/remotes/", 13)) {
+		kind = "remote branch";
+		what = remote_name + 13;
+	}
+	else {
+		kind = "";
+		what = remote_name;
+	}
+
+	remote_len = strlen(remote);
+	for (i = remote_len - 1; remote[i] == '/' && 0 <= i; i--)
+		;
+	remote_len = i + 1;
+	if (4 < i && !strncmp(".git", remote + i - 3, 4))
+		remote_len = i - 3;
+	note_len = sprintf(note, "%s\t%s\t",
+			   sha1_to_hex(commit ? commit->object.sha1 : sha1),
+			   not_for_merge ? "not-for-merge" : "");
+	if (*what) {
+		if (*kind)
+			note_len += sprintf(note + note_len, "%s ", kind);
+		note_len += sprintf(note + note_len, "'%s' of ", what);
+	}
+	note_len += sprintf(note + note_len, "%.*s", remote_len, remote);
+	fprintf(fp, "%s\n", note);
+	return update_local_ref(local_name, head, note, verbose, force);
+}
+
+int cmd_fetch__tool(int argc, const char **argv, const char *prefix)
+{
+	int verbose = 0;
+	int force = 0;
+
+	while (1 < argc) {
+		const char *arg = argv[1];
+		if (!strcmp("-v", arg))
+			verbose = 1;
+		else if (!strcmp("-f", arg))
+			force = 1;
+		else
+			break;
+		argc--;
+		argv++;
+	}
+
+	if (argc <= 1)
+		return error("Missing subcommand");
+
+	if (!strcmp("append-fetch-head", argv[1])) {
+		int result;
+		FILE *fp;
+
+		if (argc != 8)
+			return error("append-fetch-head takes 6 args");
+		fp = fopen(git_path("FETCH_HEAD"), "a");
+		result = append_fetch_head(fp, argv[2], argv[3],
+					   argv[4], argv[5],
+					   argv[6], !!argv[7][0],
+					   verbose, force);
+		fclose(fp);
+		return result;
+	}
+	if (!strcmp("update-local-ref", argv[1])) {
+		if (argc != 5)
+			return error("update-local-ref takes 3 args");
+		return update_local_ref(argv[2], argv[3], argv[4],
+					verbose, force);
+	}
+	return error("Unknown subcommand: %s", argv[1]);
+}