merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/builtin/merge-index.c

@@ -0,0 +1,111 @@
+#define USE_THE_INDEX_COMPATIBILITY_MACROS
+#include "builtin.h"
+#include "run-command.h"
+
+static const char *pgm;
+static int one_shot, quiet;
+static int err;
+
+static int merge_entry(int pos, const char *path)
+{
+	int found;
+	const char *arguments[] = { pgm, "", "", "", path, "", "", "", NULL };
+	char hexbuf[4][GIT_MAX_HEXSZ + 1];
+	char ownbuf[4][60];
+
+	if (pos >= active_nr)
+		die("git merge-index: %s not in the cache", path);
+	found = 0;
+	do {
+		const struct cache_entry *ce = active_cache[pos];
+		int stage = ce_stage(ce);
+
+		if (strcmp(ce->name, path))
+			break;
+		found++;
+		oid_to_hex_r(hexbuf[stage], &ce->oid);
+		xsnprintf(ownbuf[stage], sizeof(ownbuf[stage]), "%o", ce->ce_mode);
+		arguments[stage] = hexbuf[stage];
+		arguments[stage + 4] = ownbuf[stage];
+	} while (++pos < active_nr);
+	if (!found)
+		die("git merge-index: %s not in the cache", path);
+
+	if (run_command_v_opt(arguments, 0)) {
+		if (one_shot)
+			err++;
+		else {
+			if (!quiet)
+				die("merge program failed");
+			exit(1);
+		}
+	}
+	return found;
+}
+
+static void merge_one_path(const char *path)
+{
+	int pos = cache_name_pos(path, strlen(path));
+
+	/*
+	 * If it already exists in the cache as stage0, it's
+	 * already merged and there is nothing to do.
+	 */
+	if (pos < 0)
+		merge_entry(-pos-1, path);
+}
+
+static void merge_all(void)
+{
+	int i;
+	for (i = 0; i < active_nr; i++) {
+		const struct cache_entry *ce = active_cache[i];
+		if (!ce_stage(ce))
+			continue;
+		i += merge_entry(i, ce->name)-1;
+	}
+}
+
+int cmd_merge_index(int argc, const char **argv, const char *prefix)
+{
+	int i, force_file = 0;
+
+	/* Without this we cannot rely on waitpid() to tell
+	 * what happened to our children.
+	 */
+	signal(SIGCHLD, SIG_DFL);
+
+	if (argc < 3)
+		usage("git merge-index [-o] [-q] <merge-program> (-a | [--] [<filename>...])");
+
+	read_cache();
+
+	i = 1;
+	if (!strcmp(argv[i], "-o")) {
+		one_shot = 1;
+		i++;
+	}
+	if (!strcmp(argv[i], "-q")) {
+		quiet = 1;
+		i++;
+	}
+	pgm = argv[i++];
+	for (; i < argc; i++) {
+		const char *arg = argv[i];
+		if (!force_file && *arg == '-') {
+			if (!strcmp(arg, "--")) {
+				force_file = 1;
+				continue;
+			}
+			if (!strcmp(arg, "-a")) {
+				merge_all();
+				continue;
+			}
+			die("git merge-index: unknown option %s", arg);
+		}
+		merge_one_path(arg);
+	}
+	if (err && !quiet)
+		die("merge program failed");
+	return err;
+}