builtin/apply: make try_create_file() return -1 on error

To libify `git apply` functionality we have to signal errors to the
caller instead of die()ing.

To do that in a compatible manner with the rest of the error handling
in "builtin/apply.c", try_create_file() should return -1 in case of
error.

Unfortunately try_create_file() currently returns -1 to signal a
recoverable error. To fix that, let's make it return 1 in case of
a recoverable error and -1 in case of an unrecoverable error.

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/apply.c

@@ -4150,38 +4150,48 @@ static int add_index_file(struct apply_state *state,
 	return 0;
 }
 
+/*
+ * Returns:
+ *  -1 if an unrecoverable error happened
+ *   0 if everything went well
+ *   1 if a recoverable error happened
+ */
 static int try_create_file(const char *path, unsigned int mode, const char *buf, unsigned long size)
 {
-	int fd;
+	int fd, res;
 	struct strbuf nbuf = STRBUF_INIT;
 
 	if (S_ISGITLINK(mode)) {
 		struct stat st;
 		if (!lstat(path, &st) && S_ISDIR(st.st_mode))
 			return 0;
-		return mkdir(path, 0777);
+		return !!mkdir(path, 0777);
 	}
 
 	if (has_symlinks && S_ISLNK(mode))
 		/* Although buf:size is counted string, it also is NUL
 		 * terminated.
 		 */
-		return symlink(buf, path);
+		return !!symlink(buf, path);
 
 	fd = open(path, O_CREAT | O_EXCL | O_WRONLY, (mode & 0100) ? 0777 : 0666);
 	if (fd < 0)
-		return -1;
+		return 1;
 
 	if (convert_to_working_tree(path, buf, size, &nbuf)) {
 		size = nbuf.len;
 		buf  = nbuf.buf;
 	}
-	write_or_die(fd, buf, size);
+
+	res = write_in_full(fd, buf, size) < 0;
+	if (res)
+		error_errno(_("failed to write to '%s'"), path);
 	strbuf_release(&nbuf);
 
-	if (close(fd) < 0)
+	if (close(fd) < 0 && !res)
-		die_errno(_("closing file '%s'"), path);
+		return error_errno(_("closing file '%s'"), path);
-	return 0;
+
+	return res ? -1 : 0;
 }
 
 /*
@@ -4195,15 +4205,24 @@ static void create_one_file(struct apply_state *state,
 			    const char *buf,
 			    unsigned long size)
 {
+	int res;
+
 	if (state->cached)
 		return;
-	if (!try_create_file(path, mode, buf, size))
+
+	res = try_create_file(path, mode, buf, size);
+	if (res < 0)
+		exit(128);
+	if (!res)
 		return;
 
 	if (errno == ENOENT) {
 		if (safe_create_leading_directories(path))
 			return;
-		if (!try_create_file(path, mode, buf, size))
+		res = try_create_file(path, mode, buf, size);
+		if (res < 0)
+			exit(128);
+		if (!res)
 			return;
 	}
 
@@ -4222,7 +4241,10 @@ static void create_one_file(struct apply_state *state,
 		for (;;) {
 			char newpath[PATH_MAX];
 			mksnpath(newpath, sizeof(newpath), "%s~%u", path, nr);
-			if (!try_create_file(newpath, mode, buf, size)) {
+			res = try_create_file(newpath, mode, buf, size);
+			if (res < 0)
+				exit(128);
+			if (!res) {
 				if (!rename(newpath, path))
 					return;
 				unlink_or_warn(newpath);