Merge branch 'jk/write-file'

General code clean-up around a helper function to write a
single-liner to a file.

* jk/write-file:
  branch: use write_file_buf instead of write_file
  use write_file_buf where applicable
  write_file: add format attribute
  write_file: add pointer+len variant
  write_file: use xopen
  write_file: drop "gently" form
  branch: use non-gentle write_file for branch description
  am: ignore return value of write_file()
  config: fix bogus fd check when setting up default config

builtin/am.c

@@ -184,22 +184,22 @@ static inline const char *am_path(const struct am_state *state, const char *path
 /**
  * For convenience to call write_file()
  */
-static int write_state_text(const struct am_state *state,
+static void write_state_text(const struct am_state *state,
 			     const char *name, const char *string)
 {
-	return write_file(am_path(state, name), "%s", string);
+	write_file(am_path(state, name), "%s", string);
 }
 
-static int write_state_count(const struct am_state *state,
+static void write_state_count(const struct am_state *state,
 			      const char *name, int value)
 {
-	return write_file(am_path(state, name), "%d", value);
+	write_file(am_path(state, name), "%d", value);
 }
 
-static int write_state_bool(const struct am_state *state,
+static void write_state_bool(const struct am_state *state,
 			     const char *name, int value)
 {
-	return write_state_text(state, name, value ? "t" : "f");
+	write_state_text(state, name, value ? "t" : "f");
 }
 
 /**
@@ -403,13 +403,8 @@ static int read_commit_msg(struct am_state *state)
  */
 static void write_commit_msg(const struct am_state *state)
 {
-	int fd;
 	const char *filename = am_path(state, "final-commit");
-
+	write_file_buf(filename, state->msg, state->msg_len);
-	fd = xopen(filename, O_WRONLY | O_CREAT, 0666);
-	if (write_in_full(fd, state->msg, state->msg_len) < 0)
-		die_errno(_("could not write to %s"), filename);
-	close(fd);
 }
 
 /**

builtin/branch.c

@@ -618,10 +618,7 @@ static int edit_branch_description(const char *branch_name)
 		      "  %s\n"
 		      "Lines starting with '%c' will be stripped.\n"),
 		    branch_name, comment_line_char);
-	if (write_file_gently(git_path(edit_description), "%s", buf.buf)) {
+	write_file_buf(git_path(edit_description), buf.buf, buf.len);
-		strbuf_release(&buf);
-		return error_errno(_("could not write branch description template"));
-	}
 	strbuf_reset(&buf);
 	if (launch_editor(git_path(edit_description), &buf, NULL)) {
 		strbuf_release(&buf);

builtin/config.c

@@ -604,7 +604,7 @@ int cmd_config(int argc, const char **argv, const char *prefix)
 				      given_config_source.file : git_path("config"));
 		if (use_global_config) {
 			int fd = open(config_file, O_CREAT | O_EXCL | O_WRONLY, 0666);
-			if (fd) {
+			if (fd >= 0) {
 				char *content = default_user_config();
 				write_str_in_full(fd, content);
 				free(content);

builtin/merge.c

@@ -336,15 +336,9 @@ static void squash_message(struct commit *commit, struct commit_list *remotehead
 	struct rev_info rev;
 	struct strbuf out = STRBUF_INIT;
 	struct commit_list *j;
-	const char *filename;
-	int fd;
 	struct pretty_print_context ctx = {0};
 
 	printf(_("Squash commit -- not updating HEAD\n"));
-	filename = git_path_squash_msg();
-	fd = open(filename, O_WRONLY | O_CREAT, 0666);
-	if (fd < 0)
-		die_errno(_("Could not write to '%s'"), filename);
 
 	init_revisions(&rev, NULL);
 	rev.ignore_merges = 1;
@@ -371,10 +365,7 @@ static void squash_message(struct commit *commit, struct commit_list *remotehead
 			oid_to_hex(&commit->object.oid));
 		pretty_print_commit(&ctx, commit, &out);
 	}
-	if (write_in_full(fd, out.buf, out.len) != out.len)
+	write_file_buf(git_path_squash_msg(), out.buf, out.len);
-		die_errno(_("Writing SQUASH_MSG"));
-	if (close(fd))
-		die_errno(_("Finishing SQUASH_MSG"));
 	strbuf_release(&out);
 }
 
@@ -756,18 +747,6 @@ static void add_strategies(const char *string, unsigned attr)
 
 }
 
-static void write_merge_msg(struct strbuf *msg)
-{
-	const char *filename = git_path_merge_msg();
-	int fd = open(filename, O_WRONLY | O_CREAT, 0666);
-	if (fd < 0)
-		die_errno(_("Could not open '%s' for writing"),
-			  filename);
-	if (write_in_full(fd, msg->buf, msg->len) != msg->len)
-		die_errno(_("Could not write to '%s'"), filename);
-	close(fd);
-}
-
 static void read_merge_msg(struct strbuf *msg)
 {
 	const char *filename = git_path_merge_msg();
@@ -801,7 +780,7 @@ static void prepare_to_commit(struct commit_list *remoteheads)
 	strbuf_addch(&msg, '\n');
 	if (0 < option_edit)
 		strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
-	write_merge_msg(&msg);
+	write_file_buf(git_path_merge_msg(), msg.buf, msg.len);
 	if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
 			    git_path_merge_msg(), "merge", NULL))
 		abort_commit(remoteheads, NULL);
@@ -964,8 +943,6 @@ static int setup_with_upstream(const char ***argv)
 
 static void write_merge_state(struct commit_list *remoteheads)
 {
-	const char *filename;
-	int fd;
 	struct commit_list *j;
 	struct strbuf buf = STRBUF_INIT;
 
@@ -979,26 +956,14 @@ static void write_merge_state(struct commit_list *remoteheads)
 		}
 		strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
 	}
-	filename = git_path_merge_head();
+	write_file_buf(git_path_merge_head(), buf.buf, buf.len);
-	fd = open(filename, O_WRONLY | O_CREAT, 0666);
-	if (fd < 0)
-		die_errno(_("Could not open '%s' for writing"), filename);
-	if (write_in_full(fd, buf.buf, buf.len) != buf.len)
-		die_errno(_("Could not write to '%s'"), filename);
-	close(fd);
 	strbuf_addch(&merge_msg, '\n');
-	write_merge_msg(&merge_msg);
+	write_file_buf(git_path_merge_msg(), merge_msg.buf, merge_msg.len);
 
-	filename = git_path_merge_mode();
-	fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
-	if (fd < 0)
-		die_errno(_("Could not open '%s' for writing"), filename);
 	strbuf_reset(&buf);
 	if (fast_forward == FF_NO)
 		strbuf_addf(&buf, "no-ff");
-	if (write_in_full(fd, buf.buf, buf.len) != buf.len)
+	write_file_buf(git_path_merge_mode(), buf.buf, buf.len);
-		die_errno(_("Could not write to '%s'"), filename);
-	close(fd);
 }
 
 static int default_edit_option(void)

cache.h

@@ -1746,8 +1746,21 @@ static inline ssize_t write_str_in_full(int fd, const char *str)
 	return write_in_full(fd, str, strlen(str));
 }
 
-extern int write_file(const char *path, const char *fmt, ...);
+/**
-extern int write_file_gently(const char *path, const char *fmt, ...);
+ * Open (and truncate) the file at path, write the contents of buf to it,
+ * and close it. Dies if any errors are encountered.
+ */
+extern void write_file_buf(const char *path, const char *buf, size_t len);
+
+/**
+ * Like write_file_buf(), but format the contents into a buffer first.
+ * Additionally, write_file() will append a newline if one is not already
+ * present, making it convenient to write text files:
+ *
+ *   write_file(path, "counter: %d", ctr);
+ */
+__attribute__((format (printf, 2, 3)))
+extern void write_file(const char *path, const char *fmt, ...);
 
 /* pager.c */
 extern void setup_pager(void);

wrapper.c

@@ -651,56 +651,28 @@ int xsnprintf(char *dst, size_t max, const char *fmt, ...)
 	return len;
 }
 
-static int write_file_v(const char *path, int fatal,
+void write_file_buf(const char *path, const char *buf, size_t len)
-			const char *fmt, va_list params)
 {
-	struct strbuf sb = STRBUF_INIT;
+	int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
-	int fd = open(path, O_RDWR | O_CREAT | O_TRUNC, 0666);
+	if (write_in_full(fd, buf, len) != len)
-	if (fd < 0) {
-		if (fatal)
-			die_errno(_("could not open %s for writing"), path);
-		return -1;
-	}
-	strbuf_vaddf(&sb, fmt, params);
-	strbuf_complete_line(&sb);
-	if (write_in_full(fd, sb.buf, sb.len) != sb.len) {
-		int err = errno;
-		close(fd);
-		strbuf_release(&sb);
-		errno = err;
-		if (fatal)
 		die_errno(_("could not write to %s"), path);
-		return -1;
+	if (close(fd))
-	}
-	strbuf_release(&sb);
-	if (close(fd)) {
-		if (fatal)
 		die_errno(_("could not close %s"), path);
-		return -1;
-	}
-	return 0;
 }
 
-int write_file(const char *path, const char *fmt, ...)
+void write_file(const char *path, const char *fmt, ...)
 {
-	int status;
 	va_list params;
+	struct strbuf sb = STRBUF_INIT;
 
 	va_start(params, fmt);
-	status = write_file_v(path, 1, fmt, params);
+	strbuf_vaddf(&sb, fmt, params);
 	va_end(params);
-	return status;
-}
 
-int write_file_gently(const char *path, const char *fmt, ...)
+	strbuf_complete_line(&sb);
-{
-	int status;
-	va_list params;
 
-	va_start(params, fmt);
+	write_file_buf(path, sb.buf, sb.len);
-	status = write_file_v(path, 0, fmt, params);
+	strbuf_release(&sb);
-	va_end(params);
-	return status;
 }
 
 void sleep_millisec(int millisec)