[PATCH 2/3] Rename git-diff-tree-helper to git-diff-helper.

It used to be that diff-tree needed helper support to parse its
raw output to generate diffs, but these days git-diff-* family
produces the same output and the helper is not tied to diff-tree
anymore.  Drop "tree" from its name.

This commit is done separately to record just the rename and no
file content changes. The changes in the renamed files are recorded
in the next commit.

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

Bundled with the changes in the unrenamed files.

Signed-off-by: Petr Baudis <pasky@ucw.cz>

1 files changed, 143 insertions, 0 deletions

diff --git a/diff-helper.c b/diff-helper.c
new file mode 100644
index 0000000000..51bb658be4
--- /dev/null
+++ b/diff-helper.c
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2005 Junio C Hamano
+ */
+#include <limits.h>
+#include "cache.h"
+#include "strbuf.h"
+#include "diff.h"
+
+static int matches_pathspec(const char *name, const char **spec, int cnt)
+{
+	int i;
+	int namelen = strlen(name);
+	for (i = 0; i < cnt; i++) {
+		int speclen = strlen(spec[i]);
+		if (! strncmp(spec[i], name, speclen) &&
+		    speclen <= namelen &&
+		    (name[speclen] == 0 ||
+		     name[speclen] == '/'))
+			return 1;
+	}
+	return 0;
+}
+
+static int parse_oneside_change(const char *cp, struct diff_spec *one,
+				char *path)
+{
+	int ch;
+
+	one->file_valid = one->sha1_valid = 1;
+	one->mode = 0;
+	while ((ch = *cp) && '0' <= ch && ch <= '7') {
+		one->mode = (one->mode << 3) | (ch - '0');
+		cp++;
+	}
+
+	if (strncmp(cp, "\tblob\t", 6))
+		return -1;
+	cp += 6;
+	if (get_sha1_hex(cp, one->blob_sha1))
+		return -1;
+	cp += 40;
+	if (*cp++ != '\t')
+		return -1;
+	strcpy(path, cp);
+	return 0;
+}
+
+static int parse_diff_tree_output(const char *buf,
+				  const char **spec, int cnt, int reverse)
+{
+	struct diff_spec old, new;
+	char path[PATH_MAX];
+	const char *cp = buf;
+	int ch;
+
+	switch (*cp++) {
+	case 'U':
+		if (!cnt || matches_pathspec(cp + 1, spec, cnt))
+			diff_unmerge(cp + 1);
+		return 0;
+	case '+':
+		old.file_valid = 0;
+		parse_oneside_change(cp, &new, path);
+		break;
+	case '-':
+		new.file_valid = 0;
+		parse_oneside_change(cp, &old, path);
+		break;
+	case '*':
+		old.file_valid = old.sha1_valid =
+			new.file_valid = new.sha1_valid = 1;
+		old.mode = new.mode = 0;
+		while ((ch = *cp) && ('0' <= ch && ch <= '7')) {
+			old.mode = (old.mode << 3) | (ch - '0');
+			cp++;
+		}
+		if (strncmp(cp, "->", 2))
+			return -1;
+		cp += 2;
+		while ((ch = *cp) && ('0' <= ch && ch <= '7')) {
+			new.mode = (new.mode << 3) | (ch - '0');
+			cp++;
+		}
+		if (strncmp(cp, "\tblob\t", 6))
+			return -1;
+		cp += 6;
+		if (get_sha1_hex(cp, old.blob_sha1))
+			return -1;
+		cp += 40;
+		if (strncmp(cp, "->", 2))
+			return -1;
+		cp += 2;
+		if (get_sha1_hex(cp, new.blob_sha1))
+			return -1;
+		cp += 40;
+		if (*cp++ != '\t')
+			return -1;
+		strcpy(path, cp);
+		break;
+	default:
+		return -1;
+	}
+	if (!cnt || matches_pathspec(path, spec, cnt)) {
+		if (reverse)
+			run_external_diff(path, &new, &old);
+		else
+			run_external_diff(path, &old, &new);
+	}
+	return 0;
+}
+
+static const char *diff_tree_helper_usage =
+"diff-tree-helper [-R] [-z] paths...";
+
+int main(int ac, const char **av) {
+	struct strbuf sb;
+	int reverse = 0;
+	int line_termination = '\n';
+
+	strbuf_init(&sb);
+
+	while (1 < ac && av[1][0] == '-') {
+		if (av[1][1] == 'R')
+			reverse = 1;
+		else if (av[1][1] == 'z')
+			line_termination = 0;
+		else
+			usage(diff_tree_helper_usage);
+		ac--; av++;
+	}
+	/* the remaining parameters are paths patterns */
+
+	while (1) {
+		int status;
+		read_line(&sb, stdin, line_termination);
+		if (sb.eof)
+			break;
+		status = parse_diff_tree_output(sb.buf, av+1, ac-1, reverse);
+		if (status)
+			fprintf(stderr, "cannot parse %s\n", sb.buf);
+	}
+	return 0;
+}