checkout: don't recreate previous directory

Don't bother trying to recreate the previously created directory
during checkout, for a modest reduction in the number of stats.

src/checkout.c

@@ -63,6 +63,7 @@ typedef struct {
 	size_t total_steps;
 	size_t completed_steps;
 	git_checkout_perfdata perfdata;
+	git_buf last_mkdir;
 } checkout_data;
 
 typedef struct {
@@ -1216,9 +1217,24 @@ static int checkout_mkdir(
 static int mkpath2file(
 	checkout_data *data, const char *path, unsigned int mode)
 {
-	return checkout_mkdir(
-		data, path, git_repository_workdir(data->repo), mode,
-		GIT_MKDIR_PATH | GIT_MKDIR_SKIP_LAST | GIT_MKDIR_VERIFY_DIR);
+	git_buf *mkdir_path = &data->tmp;
+	int error;
+
+	if ((error = git_buf_sets(mkdir_path, path)) < 0)
+		return error;
+
+	git_buf_rtruncate_at_char(mkdir_path, '/');
+
+	if (data->last_mkdir.size && mkdir_path->size == data->last_mkdir.size &&
+		memcmp(mkdir_path->ptr, data->last_mkdir.ptr, mkdir_path->size) == 0)
+		return 0;
+
+	if ((error = checkout_mkdir(
+			data, mkdir_path->ptr, data->opts.target_directory, mode,
+			GIT_MKDIR_PATH | GIT_MKDIR_VERIFY_DIR)) == 0)
+		git_buf_swap(&data->last_mkdir, mkdir_path);
+
+	return error;
 }
 
 static int buffer_to_file(

src/fileops.c

@@ -352,26 +352,40 @@ int git_futils_mkdir_withperf(
 		*tail = '\0';
 		st.st_mode = 0;
 
-		/* make directory */
-		perfdata->mkdir_calls++;
+		/* See what's going on with this path component */
+		perfdata->stat_calls++;
+
+		if (p_lstat(make_path.ptr, &st) < 0) {
+			perfdata->mkdir_calls++;
 
-		if (p_mkdir(make_path.ptr, mode) < 0) {
-			int tmp_errno = giterr_system_last();
+			if (errno != ENOENT || p_mkdir(make_path.ptr, mode) < 0) {
+				giterr_set(GITERR_OS, "Failed to make directory '%s'", make_path.ptr);
+				error = GIT_EEXISTS;
+				goto done;
+			}
+
+			giterr_clear();
+		} else {
+			/* with exclusive create, existing dir is an error */
+			if ((flags & GIT_MKDIR_EXCL) != 0) {
+				giterr_set(GITERR_INVALID, "Failed to make directory '%s': directory exists", make_path.ptr);
+				error = GIT_EEXISTS;
+				goto done;
+			}
 
-			/* ignore error if not at end or if directory already exists */
-			if (lastch == '\0') {
+			if (S_ISLNK(st.st_mode)) {
 				perfdata->stat_calls++;
 
-				if (p_stat(make_path.ptr, &st) < 0 || !S_ISDIR(st.st_mode)) {
-					giterr_system_set(tmp_errno);
+				/* Re-stat the target, make sure it's a directory */
+				if (p_stat(make_path.ptr, &st) < 0) {
 					giterr_set(GITERR_OS, "Failed to make directory '%s'", make_path.ptr);
+					error = GIT_EEXISTS;
 					goto done;
 				}
 			}
 
-			/* with exclusive create, existing dir is an error */
-			if ((flags & GIT_MKDIR_EXCL) != 0) {
-				giterr_set(GITERR_OS, "Directory already exists '%s'", make_path.ptr);
+			if (!S_ISDIR(st.st_mode)) {
+				giterr_set(GITERR_INVALID, "Failed to make directory '%s': directory exists", make_path.ptr);
 				error = GIT_EEXISTS;
 				goto done;
 			}