[PATCH v2 51/94] builtin/apply: make apply_patch() return -1 instead of die()ing

[Christian Couder <christian.couder@gmail.com>]

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

As a first step in this direction, let's make apply_patch() return
-1 in case of errors instead of dying. For now its only caller
apply_all_patches() will exit(1) when apply_patch() return -1.

In a later patch, apply_all_patches() will return -1 too instead of
exiting.

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
---
 builtin/apply.c | 54 +++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 39 insertions(+), 15 deletions(-)

diff --git a/builtin/apply.c b/builtin/apply.c
index ec55768..d95630c 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -4512,6 +4512,14 @@ static int write_out_results(struct apply_state *state, struct patch *list)
 #define INACCURATE_EOF	(1<<0)
 #define RECOUNT		(1<<1)
 
+/*
+ * Try to apply a patch.
+ *
+ * Returns:
+ *  -1 if an error happened
+ *   0 if the patch applied
+ *   1 if the patch did not apply
+ */
 static int apply_patch(struct apply_state *state,
 		       int fd,
 		       const char *filename,
@@ -4521,6 +4529,7 @@ static int apply_patch(struct apply_state *state,
 	struct strbuf buf = STRBUF_INIT; /* owns the patch text */
 	struct patch *list = NULL, **listp = &list;
 	int skipped_patch = 0;
+	int res = 0;
 
 	state->patch_input_file = filename;
 	read_patch_file(&buf, fd);
@@ -4553,8 +4562,10 @@ static int apply_patch(struct apply_state *state,
 		offset += nr;
 	}
 
-	if (!list && !skipped_patch)
-		die(_("unrecognized input"));
+	if (!list && !skipped_patch) {
+		res = error(_("unrecognized input"));
+		goto end;
+	}
 
 	if (state->whitespace_error && (state->ws_error_action == die_on_ws_error))
 		state->apply = 0;
@@ -4563,21 +4574,22 @@ static int apply_patch(struct apply_state *state,
 	if (state->update_index && state->newfd < 0)
 		state->newfd = hold_locked_index(state->lock_file, 1);
 
-	if (state->check_index) {
-		if (read_cache() < 0)
-			die(_("unable to read index file"));
+	if (state->check_index && read_cache() < 0) {
+		res = error(_("unable to read index file"));
+		goto end;
 	}
 
 	if ((state->check || state->apply) &&
 	    check_patch_list(state, list) < 0 &&
-	    !state->apply_with_reject)
-		exit(1);
+	    !state->apply_with_reject) {
+		res = -1;
+		goto end;
+	}
 
 	if (state->apply && write_out_results(state, list)) {
-		if (state->apply_with_reject)
-			exit(1);
 		/* with --3way, we still need to write the index out */
-		return 1;
+		res = state->apply_with_reject ? -1 : 1;
+		goto end;
 	}
 
 	if (state->fake_ancestor)
@@ -4592,10 +4604,11 @@ static int apply_patch(struct apply_state *state,
 	if (state->summary)
 		summary_patch_list(list);
 
+end:
 	free_patch_list(list);
 	strbuf_release(&buf);
 	string_list_clear(&state->fn_table, 0);
-	return 0;
+	return res;
 }
 
 static void git_apply_config(void)
@@ -4722,6 +4735,7 @@ static int apply_all_patches(struct apply_state *state,
 			     int options)
 {
 	int i;
+	int res;
 	int errs = 0;
 	int read_stdin = 1;
 
@@ -4730,7 +4744,10 @@ static int apply_all_patches(struct apply_state *state,
 		int fd;
 
 		if (!strcmp(arg, "-")) {
-			errs |= apply_patch(state, 0, "<stdin>", options);
+			res = apply_patch(state, 0, "<stdin>", options);
+			if (res < 0)
+				exit(1);
+			errs |= res;
 			read_stdin = 0;
 			continue;
 		} else if (0 < state->prefix_length)
@@ -4743,12 +4760,19 @@ static int apply_all_patches(struct apply_state *state,
 			die_errno(_("can't open patch '%s'"), arg);
 		read_stdin = 0;
 		set_default_whitespace_mode(state);
-		errs |= apply_patch(state, fd, arg, options);
+		res = apply_patch(state, fd, arg, options);
+		if (res < 0)
+			exit(1);
+		errs |= res;
 		close(fd);
 	}
 	set_default_whitespace_mode(state);
-	if (read_stdin)
-		errs |= apply_patch(state, 0, "<stdin>", options);
+	if (read_stdin) {
+		res = apply_patch(state, 0, "<stdin>", options);
+		if (res < 0)
+			exit(1);
+		errs |= res;
+	}
 
 	if (state->whitespace_error) {
 		if (state->squelch_whitespace_errors &&
-- 
2.8.2.490.g3dabe57