[PATCH v4 20/27] use new wrapper write_file() for simple file writing

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

This fixes common problems in these code about error handling,
forgetting to close the file handle after fprintf() fails, or not
printing out the error string..

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 builtin/branch.c  |  4 +---
 builtin/init-db.c |  7 +------
 daemon.c          | 11 +----------
 submodule.c       |  9 ++-------
 transport.c       |  8 +++-----
 5 files changed, 8 insertions(+), 31 deletions(-)

diff --git a/builtin/branch.c b/builtin/branch.c
index b4d7716..3eebdbc 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -754,7 +754,6 @@ static const char edit_description[] = "BRANCH_DESCRIPTION";
 
 static int edit_branch_description(const char *branch_name)
 {
-	FILE *fp;
 	int status;
 	struct strbuf buf = STRBUF_INIT;
 	struct strbuf name = STRBUF_INIT;
@@ -767,8 +766,7 @@ static int edit_branch_description(const char *branch_name)
 		    "  %s\n"
 		    "Lines starting with '%c' will be stripped.\n",
 		    branch_name, comment_line_char);
-	fp = fopen(git_path(edit_description), "w");
-	if ((fwrite(buf.buf, 1, buf.len, fp) < buf.len) || fclose(fp)) {
+	if (write_file(git_path(edit_description), 0, "%s", buf.buf)) {
 		strbuf_release(&buf);
 		return error(_("could not write branch description template: %s"),
 			     strerror(errno));
diff --git a/builtin/init-db.c b/builtin/init-db.c
index c7c76bb..081e512 100644
--- a/builtin/init-db.c
+++ b/builtin/init-db.c
@@ -342,7 +342,6 @@ int set_git_dir_init(const char *git_dir, const char *real_git_dir,
 static void separate_git_dir(const char *git_dir)
 {
 	struct stat st;
-	FILE *fp;
 
 	if (!stat(git_link, &st)) {
 		const char *src;
@@ -358,11 +357,7 @@ static void separate_git_dir(const char *git_dir)
 			die_errno(_("unable to move %s to %s"), src, git_dir);
 	}
 
-	fp = fopen(git_link, "w");
-	if (!fp)
-		die(_("Could not create git link %s"), git_link);
-	fprintf(fp, "gitdir: %s\n", git_dir);
-	fclose(fp);
+	write_file(git_link, 1, "gitdir: %s\n", git_dir);
 }
 
 int init_db(const char *template_dir, unsigned int flags)
diff --git a/daemon.c b/daemon.c
index 503e039..b880d30 100644
--- a/daemon.c
+++ b/daemon.c
@@ -1122,15 +1122,6 @@ static void daemonize(void)
 }
 #endif
 
-static void store_pid(const char *path)
-{
-	FILE *f = fopen(path, "w");
-	if (!f)
-		die_errno("cannot open pid file '%s'", path);
-	if (fprintf(f, "%"PRIuMAX"\n", (uintmax_t) getpid()) < 0 || fclose(f) != 0)
-		die_errno("failed to write pid file '%s'", path);
-}
-
 static int serve(struct string_list *listen_addr, int listen_port,
     struct credentials *cred)
 {
@@ -1339,7 +1330,7 @@ int main(int argc, char **argv)
 		sanitize_stdfds();
 
 	if (pid_file)
-		store_pid(pid_file);
+		write_file(pid_file, 1, "%"PRIuMAX"\n", (uintmax_t) getpid());
 
 	/* prepare argv for serving-processes */
 	cld_argv = xmalloc(sizeof (char *) * (argc + 2));
diff --git a/submodule.c b/submodule.c
index 613857e..fe5748d 100644
--- a/submodule.c
+++ b/submodule.c
@@ -1135,16 +1135,11 @@ void connect_work_tree_and_git_dir(const char *work_tree, const char *git_dir)
 	struct strbuf file_name = STRBUF_INIT;
 	struct strbuf rel_path = STRBUF_INIT;
 	const char *real_work_tree = xstrdup(real_path(work_tree));
-	FILE *fp;
 
 	/* Update gitfile */
 	strbuf_addf(&file_name, "%s/.git", work_tree);
-	fp = fopen(file_name.buf, "w");
-	if (!fp)
-		die(_("Could not create git link %s"), file_name.buf);
-	fprintf(fp, "gitdir: %s\n", relative_path(git_dir, real_work_tree,
-						  &rel_path));
-	fclose(fp);
+	write_file(file_name.buf, 1, "gitdir: %s\n",
+		   relative_path(git_dir, real_work_tree, &rel_path));
 
 	/* Update core.worktree setting */
 	strbuf_reset(&file_name);
diff --git a/transport.c b/transport.c
index ca7bb44..2df8a15 100644
--- a/transport.c
+++ b/transport.c
@@ -294,7 +294,6 @@ static int write_one_ref(const char *name, const unsigned char *sha1,
 {
 	struct strbuf *buf = data;
 	int len = buf->len;
-	FILE *f;
 
 	/* when called via for_each_ref(), flags is non-zero */
 	if (flags && !starts_with(name, "refs/heads/") &&
@@ -303,10 +302,9 @@ static int write_one_ref(const char *name, const unsigned char *sha1,
 
 	strbuf_addstr(buf, name);
 	if (safe_create_leading_directories(buf->buf) ||
-			!(f = fopen(buf->buf, "w")) ||
-			fprintf(f, "%s\n", sha1_to_hex(sha1)) < 0 ||
-			fclose(f))
-		return error("problems writing temporary file %s", buf->buf);
+	    write_file(buf->buf, 0, "%s\n", sha1_to_hex(sha1)))
+		return error("problems writing temporary file %s: %s",
+			     buf->buf, strerror(errno));
 	strbuf_setlen(buf, len);
 	return 0;
 }
-- 
1.9.0.40.gaa8c3ea