1 files changed, 311 insertions, 0 deletions
diff --git a/third_party/git/diff-no-index.c b/third_party/git/diff-no-index.c
new file mode 100644
index 000000000000..7814eabfe028
--- /dev/null
+++ b/third_party/git/diff-no-index.c
@@ -0,0 +1,311 @@
+/*
+ * "diff --no-index" support
+ * Copyright (c) 2007 by Johannes Schindelin
+ * Copyright (c) 2008 by Junio C Hamano
+ */
+
+#include "cache.h"
+#include "color.h"
+#include "commit.h"
+#include "blob.h"
+#include "tag.h"
+#include "diff.h"
+#include "diffcore.h"
+#include "revision.h"
+#include "log-tree.h"
+#include "builtin.h"
+#include "parse-options.h"
+#include "string-list.h"
+#include "dir.h"
+
+static int read_directory_contents(const char *path, struct string_list *list)
+{
+	DIR *dir;
+	struct dirent *e;
+
+	if (!(dir = opendir(path)))
+		return error("Could not open directory %s", path);
+
+	while ((e = readdir(dir)))
+		if (!is_dot_or_dotdot(e->d_name))
+			string_list_insert(list, e->d_name);
+
+	closedir(dir);
+	return 0;
+}
+
+/*
+ * This should be "(standard input)" or something, but it will
+ * probably expose many more breakages in the way no-index code
+ * is bolted onto the diff callchain.
+ */
+static const char file_from_standard_input[] = "-";
+
+static int get_mode(const char *path, int *mode)
+{
+	struct stat st;
+
+	if (!path || !strcmp(path, "/dev/null"))
+		*mode = 0;
+#ifdef GIT_WINDOWS_NATIVE
+	else if (!strcasecmp(path, "nul"))
+		*mode = 0;
+#endif
+	else if (path == file_from_standard_input)
+		*mode = create_ce_mode(0666);
+	else if (lstat(path, &st))
+		return error("Could not access '%s'", path);
+	else
+		*mode = st.st_mode;
+	return 0;
+}
+
+static int populate_from_stdin(struct diff_filespec *s)
+{
+	struct strbuf buf = STRBUF_INIT;
+	size_t size = 0;
+
+	if (strbuf_read(&buf, 0, 0) < 0)
+		return error_errno("error while reading from stdin");
+
+	s->should_munmap = 0;
+	s->data = strbuf_detach(&buf, &size);
+	s->size = size;
+	s->should_free = 1;
+	s->is_stdin = 1;
+	return 0;
+}
+
+static struct diff_filespec *noindex_filespec(const char *name, int mode)
+{
+	struct diff_filespec *s;
+
+	if (!name)
+		name = "/dev/null";
+	s = alloc_filespec(name);
+	fill_filespec(s, &null_oid, 0, mode);
+	if (name == file_from_standard_input)
+		populate_from_stdin(s);
+	return s;
+}
+
+static int queue_diff(struct diff_options *o,
+		      const char *name1, const char *name2)
+{
+	int mode1 = 0, mode2 = 0;
+
+	if (get_mode(name1, &mode1) || get_mode(name2, &mode2))
+		return -1;
+
+	if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2)) {
+		struct diff_filespec *d1, *d2;
+
+		if (S_ISDIR(mode1)) {
+			/* 2 is file that is created */
+			d1 = noindex_filespec(NULL, 0);
+			d2 = noindex_filespec(name2, mode2);
+			name2 = NULL;
+			mode2 = 0;
+		} else {
+			/* 1 is file that is deleted */
+			d1 = noindex_filespec(name1, mode1);
+			d2 = noindex_filespec(NULL, 0);
+			name1 = NULL;
+			mode1 = 0;
+		}
+		/* emit that file */
+		diff_queue(&diff_queued_diff, d1, d2);
+
+		/* and then let the entire directory be created or deleted */
+	}
+
+	if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
+		struct strbuf buffer1 = STRBUF_INIT;
+		struct strbuf buffer2 = STRBUF_INIT;
+		struct string_list p1 = STRING_LIST_INIT_DUP;
+		struct string_list p2 = STRING_LIST_INIT_DUP;
+		int i1, i2, ret = 0;
+		size_t len1 = 0, len2 = 0;
+
+		if (name1 && read_directory_contents(name1, &p1))
+			return -1;
+		if (name2 && read_directory_contents(name2, &p2)) {
+			string_list_clear(&p1, 0);
+			return -1;
+		}
+
+		if (name1) {
+			strbuf_addstr(&buffer1, name1);
+			strbuf_complete(&buffer1, '/');
+			len1 = buffer1.len;
+		}
+
+		if (name2) {
+			strbuf_addstr(&buffer2, name2);
+			strbuf_complete(&buffer2, '/');
+			len2 = buffer2.len;
+		}
+
+		for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
+			const char *n1, *n2;
+			int comp;
+
+			strbuf_setlen(&buffer1, len1);
+			strbuf_setlen(&buffer2, len2);
+
+			if (i1 == p1.nr)
+				comp = 1;
+			else if (i2 == p2.nr)
+				comp = -1;
+			else
+				comp = strcmp(p1.items[i1].string, p2.items[i2].string);
+
+			if (comp > 0)
+				n1 = NULL;
+			else {
+				strbuf_addstr(&buffer1, p1.items[i1++].string);
+				n1 = buffer1.buf;
+			}
+
+			if (comp < 0)
+				n2 = NULL;
+			else {
+				strbuf_addstr(&buffer2, p2.items[i2++].string);
+				n2 = buffer2.buf;
+			}
+
+			ret = queue_diff(o, n1, n2);
+		}
+		string_list_clear(&p1, 0);
+		string_list_clear(&p2, 0);
+		strbuf_release(&buffer1);
+		strbuf_release(&buffer2);
+
+		return ret;
+	} else {
+		struct diff_filespec *d1, *d2;
+
+		if (o->flags.reverse_diff) {
+			SWAP(mode1, mode2);
+			SWAP(name1, name2);
+		}
+
+		d1 = noindex_filespec(name1, mode1);
+		d2 = noindex_filespec(name2, mode2);
+		diff_queue(&diff_queued_diff, d1, d2);
+		return 0;
+	}
+}
+
+/* append basename of F to D */
+static void append_basename(struct strbuf *path, const char *dir, const char *file)
+{
+	const char *tail = strrchr(file, '/');
+
+	strbuf_addstr(path, dir);
+	while (path->len && path->buf[path->len - 1] == '/')
+		path->len--;
+	strbuf_addch(path, '/');
+	strbuf_addstr(path, tail ? tail + 1 : file);
+}
+
+/*
+ * DWIM "diff D F" into "diff D/F F" and "diff F D" into "diff F D/F"
+ * Note that we append the basename of F to D/, so "diff a/b/file D"
+ * becomes "diff a/b/file D/file", not "diff a/b/file D/a/b/file".
+ */
+static void fixup_paths(const char **path, struct strbuf *replacement)
+{
+	unsigned int isdir0, isdir1;
+
+	if (path[0] == file_from_standard_input ||
+	    path[1] == file_from_standard_input)
+		return;
+	isdir0 = is_directory(path[0]);
+	isdir1 = is_directory(path[1]);
+	if (isdir0 == isdir1)
+		return;
+	if (isdir0) {
+		append_basename(replacement, path[0], path[1]);
+		path[0] = replacement->buf;
+	} else {
+		append_basename(replacement, path[1], path[0]);
+		path[1] = replacement->buf;
+	}
+}
+
+static const char * const diff_no_index_usage[] = {
+	N_("git diff --no-index [<options>] <path> <path>"),
+	NULL
+};
+
+int diff_no_index(struct rev_info *revs,
+		  int implicit_no_index,
+		  int argc, const char **argv)
+{
+	int i, no_index;
+	const char *paths[2];
+	struct strbuf replacement = STRBUF_INIT;
+	const char *prefix = revs->prefix;
+	struct option no_index_options[] = {
+		OPT_BOOL_F(0, "no-index", &no_index, "",
+			   PARSE_OPT_NONEG | PARSE_OPT_HIDDEN),
+		OPT_END(),
+	};
+	struct option *options;
+
+	options = parse_options_concat(no_index_options,
+				       revs->diffopt.parseopts);
+	argc = parse_options(argc, argv, revs->prefix, options,
+			     diff_no_index_usage, 0);
+	if (argc != 2) {
+		if (implicit_no_index)
+			warning(_("Not a git repository. Use --no-index to "
+				  "compare two paths outside a working tree"));
+		usage_with_options(diff_no_index_usage, options);
+	}
+	FREE_AND_NULL(options);
+	for (i = 0; i < 2; i++) {
+		const char *p = argv[argc - 2 + i];
+		if (!strcmp(p, "-"))
+			/*
+			 * stdin should be spelled as "-"; if you have
+			 * path that is "-", spell it as "./-".
+			 */
+			p = file_from_standard_input;
+		else if (prefix)
+			p = prefix_filename(prefix, p);
+		paths[i] = p;
+	}
+
+	fixup_paths(paths, &replacement);
+
+	revs->diffopt.skip_stat_unmatch = 1;
+	if (!revs->diffopt.output_format)
+		revs->diffopt.output_format = DIFF_FORMAT_PATCH;
+
+	revs->diffopt.flags.no_index = 1;
+
+	revs->diffopt.flags.relative_name = 1;
+	revs->diffopt.prefix = prefix;
+
+	revs->max_count = -2;
+	diff_setup_done(&revs->diffopt);
+
+	setup_diff_pager(&revs->diffopt);
+	revs->diffopt.flags.exit_with_status = 1;
+
+	if (queue_diff(&revs->diffopt, paths[0], paths[1]))
+		return 1;
+	diff_set_mnemonic_prefix(&revs->diffopt, "1/", "2/");
+	diffcore_std(&revs->diffopt);
+	diff_flush(&revs->diffopt);
+
+	strbuf_release(&replacement);
+
+	/*
+	 * The return code for --no-index imitates diff(1):
+	 * 0 = no changes, 1 = changes, else error
+	 */
+	return diff_result_code(&revs->diffopt, 0);
+}