[PATCH v4 09/23] rebase: use read_oneliner()

[Denton Liu <liu.denton@xxxxxxxxx>]

Since in sequencer.c, read_one() basically duplicates the functionality
of read_oneliner(), reduce code duplication by replacing read_one() with
read_oneliner(). Also, delete strbuf_reset() calls prior to
read_oneliner() as read_oneliner() already resets the strbuf.

This was mostly done with the following Coccinelle script

	@@
	expression a, b;
	@@
	- read_one(a, b)
	+ !read_oneliner(b, a, READ_ONELINER_WARN_NON_EXISTENCE)

Long lines were broken up and strbuf_reset()s were deleted manually.

Signed-off-by: Denton Liu <liu.denton@xxxxxxxxx>
---
 builtin/rebase.c | 42 +++++++++++++++++-------------------------
 1 file changed, 17 insertions(+), 25 deletions(-)

diff --git a/builtin/rebase.c b/builtin/rebase.c
index bff53d5d16..91873fa0b5 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -586,15 +586,6 @@ static const char *state_dir_path(const char *filename, struct rebase_options *o
 	return path.buf;
 }
 
-/* Read one file, then strip line endings */
-static int read_one(const char *path, struct strbuf *buf)
-{
-	if (strbuf_read_file(buf, path, 0) < 0)
-		return error_errno(_("could not read '%s'"), path);
-	strbuf_trim_trailing_newline(buf);
-	return 0;
-}
-
 /* Initialize the rebase options from the state directory. */
 static int read_basic_state(struct rebase_options *opts)
 {
@@ -602,8 +593,10 @@ static int read_basic_state(struct rebase_options *opts)
 	struct strbuf buf = STRBUF_INIT;
 	struct object_id oid;
 
-	if (read_one(state_dir_path("head-name", opts), &head_name) ||
-	    read_one(state_dir_path("onto", opts), &buf))
+	if (!read_oneliner(&head_name, state_dir_path("head-name", opts),
+			   READ_ONELINER_WARN_MISSING) ||
+	    !read_oneliner(&buf, state_dir_path("onto", opts),
+			   READ_ONELINER_WARN_MISSING))
 		return -1;
 	opts->head_name = starts_with(head_name.buf, "refs/") ?
 		xstrdup(head_name.buf) : NULL;
@@ -617,11 +610,12 @@ static int read_basic_state(struct rebase_options *opts)
 	 * head. Fall back to reading from head to cover for the case that the
 	 * user upgraded git with an ongoing interactive rebase.
 	 */
-	strbuf_reset(&buf);
 	if (file_exists(state_dir_path("orig-head", opts))) {
-		if (read_one(state_dir_path("orig-head", opts), &buf))
+		if (!read_oneliner(&buf, state_dir_path("orig-head", opts),
+				   READ_ONELINER_WARN_MISSING))
 			return -1;
-	} else if (read_one(state_dir_path("head", opts), &buf))
+	} else if (!read_oneliner(&buf, state_dir_path("head", opts),
+				  READ_ONELINER_WARN_MISSING))
 		return -1;
 	if (get_oid(buf.buf, &opts->orig_head))
 		return error(_("invalid orig-head: '%s'"), buf.buf);
@@ -640,9 +634,8 @@ static int read_basic_state(struct rebase_options *opts)
 	}
 
 	if (file_exists(state_dir_path("allow_rerere_autoupdate", opts))) {
-		strbuf_reset(&buf);
-		if (read_one(state_dir_path("allow_rerere_autoupdate", opts),
-			    &buf))
+		if (!read_oneliner(&buf, state_dir_path("allow_rerere_autoupdate", opts),
+				   READ_ONELINER_WARN_MISSING))
 			return -1;
 		if (!strcmp(buf.buf, "--rerere-autoupdate"))
 			opts->allow_rerere_autoupdate = RERERE_AUTOUPDATE;
@@ -654,25 +647,24 @@ static int read_basic_state(struct rebase_options *opts)
 	}
 
 	if (file_exists(state_dir_path("gpg_sign_opt", opts))) {
-		strbuf_reset(&buf);
-		if (read_one(state_dir_path("gpg_sign_opt", opts),
-			    &buf))
+		if (!read_oneliner(&buf, state_dir_path("gpg_sign_opt", opts),
+				   READ_ONELINER_WARN_MISSING))
 			return -1;
 		free(opts->gpg_sign_opt);
 		opts->gpg_sign_opt = xstrdup(buf.buf);
 	}
 
 	if (file_exists(state_dir_path("strategy", opts))) {
-		strbuf_reset(&buf);
-		if (read_one(state_dir_path("strategy", opts), &buf))
+		if (!read_oneliner(&buf, state_dir_path("strategy", opts),
+				   READ_ONELINER_WARN_MISSING))
 			return -1;
 		free(opts->strategy);
 		opts->strategy = xstrdup(buf.buf);
 	}
 
 	if (file_exists(state_dir_path("strategy_opts", opts))) {
-		strbuf_reset(&buf);
-		if (read_one(state_dir_path("strategy_opts", opts), &buf))
+		if (!read_oneliner(&buf, state_dir_path("strategy_opts", opts),
+				   READ_ONELINER_WARN_MISSING))
 			return -1;
 		free(opts->strategy_opts);
 		opts->strategy_opts = xstrdup(buf.buf);
@@ -724,7 +716,7 @@ static int apply_autostash(struct rebase_options *opts)
 	if (!file_exists(path))
 		return 0;
 
-	if (read_one(path, &autostash))
+	if (!read_oneliner(&autostash, path, READ_ONELINER_WARN_MISSING))
 		return error(_("Could not read '%s'"), path);
 	/* Ensure that the hash is not mistaken for a number */
 	strbuf_addstr(&autostash, "^0");
-- 
2.26.0.159.g23e2136ad0