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

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

third_party/git/builtin/merge-file.c

@@ -0,0 +1,118 @@
+#include "builtin.h"
+#include "cache.h"
+#include "config.h"
+#include "xdiff/xdiff.h"
+#include "xdiff-interface.h"
+#include "parse-options.h"
+
+static const char *const merge_file_usage[] = {
+	N_("git merge-file [<options>] [-L <name1> [-L <orig> [-L <name2>]]] <file1> <orig-file> <file2>"),
+	NULL
+};
+
+static int label_cb(const struct option *opt, const char *arg, int unset)
+{
+	static int label_count = 0;
+	const char **names = (const char **)opt->value;
+
+	BUG_ON_OPT_NEG(unset);
+
+	if (label_count >= 3)
+		return error("too many labels on the command line");
+	names[label_count++] = arg;
+	return 0;
+}
+
+int cmd_merge_file(int argc, const char **argv, const char *prefix)
+{
+	const char *names[3] = { NULL, NULL, NULL };
+	mmfile_t mmfs[3];
+	mmbuffer_t result = {NULL, 0};
+	xmparam_t xmp = {{0}};
+	int ret = 0, i = 0, to_stdout = 0;
+	int quiet = 0;
+	struct option options[] = {
+		OPT_BOOL('p', "stdout", &to_stdout, N_("send results to standard output")),
+		OPT_SET_INT(0, "diff3", &xmp.style, N_("use a diff3 based merge"), XDL_MERGE_DIFF3),
+		OPT_SET_INT(0, "ours", &xmp.favor, N_("for conflicts, use our version"),
+			    XDL_MERGE_FAVOR_OURS),
+		OPT_SET_INT(0, "theirs", &xmp.favor, N_("for conflicts, use their version"),
+			    XDL_MERGE_FAVOR_THEIRS),
+		OPT_SET_INT(0, "union", &xmp.favor, N_("for conflicts, use a union version"),
+			    XDL_MERGE_FAVOR_UNION),
+		OPT_INTEGER(0, "marker-size", &xmp.marker_size,
+			    N_("for conflicts, use this marker size")),
+		OPT__QUIET(&quiet, N_("do not warn about conflicts")),
+		OPT_CALLBACK('L', NULL, names, N_("name"),
+			     N_("set labels for file1/orig-file/file2"), &label_cb),
+		OPT_END(),
+	};
+
+	xmp.level = XDL_MERGE_ZEALOUS_ALNUM;
+	xmp.style = 0;
+	xmp.favor = 0;
+
+	if (startup_info->have_repository) {
+		/* Read the configuration file */
+		git_config(git_xmerge_config, NULL);
+		if (0 <= git_xmerge_style)
+			xmp.style = git_xmerge_style;
+	}
+
+	argc = parse_options(argc, argv, prefix, options, merge_file_usage, 0);
+	if (argc != 3)
+		usage_with_options(merge_file_usage, options);
+	if (quiet) {
+		if (!freopen("/dev/null", "w", stderr))
+			return error_errno("failed to redirect stderr to /dev/null");
+	}
+
+	for (i = 0; i < 3; i++) {
+		char *fname;
+		int ret;
+
+		if (!names[i])
+			names[i] = argv[i];
+
+		fname = prefix_filename(prefix, argv[i]);
+		ret = read_mmfile(mmfs + i, fname);
+		free(fname);
+		if (ret)
+			return -1;
+
+		if (mmfs[i].size > MAX_XDIFF_SIZE ||
+		    buffer_is_binary(mmfs[i].ptr, mmfs[i].size))
+			return error("Cannot merge binary files: %s",
+					argv[i]);
+	}
+
+	xmp.ancestor = names[1];
+	xmp.file1 = names[0];
+	xmp.file2 = names[2];
+	ret = xdl_merge(mmfs + 1, mmfs + 0, mmfs + 2, &xmp, &result);
+
+	for (i = 0; i < 3; i++)
+		free(mmfs[i].ptr);
+
+	if (ret >= 0) {
+		const char *filename = argv[0];
+		char *fpath = prefix_filename(prefix, argv[0]);
+		FILE *f = to_stdout ? stdout : fopen(fpath, "wb");
+
+		if (!f)
+			ret = error_errno("Could not open %s for writing",
+					  filename);
+		else if (result.size &&
+			 fwrite(result.ptr, result.size, 1, f) != 1)
+			ret = error_errno("Could not write to %s", filename);
+		else if (fclose(f))
+			ret = error_errno("Could not close %s", filename);
+		free(result.ptr);
+		free(fpath);
+	}
+
+	if (ret > 127)
+		ret = 127;
+
+	return ret;
+}