builtin-am: implement --[no-]scissors

Since 017678b (am/mailinfo: Disable scissors processing by default,
2009-08-26), git-am supported the --[no-]scissors option, passing it to
git-mailinfo.

Re-implement support for this option in builtin/am.c.

Since the default setting of --scissors in git-mailinfo can be
configured with mailinfo.scissors (and perhaps through other settings in
the future), to be safe we make an explicit distinction between
SCISSORS_UNSET, SCISSORS_TRUE and SCISSORS_FALSE.

Signed-off-by: Paul Tan <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pyokagan

builtin/am.c

@@ -74,6 +74,12 @@ enum keep_type {
 	KEEP_NON_PATCH  /* pass -b flag to git-mailinfo */
 };
 
+enum scissors_type {
+	SCISSORS_UNSET = -1,
+	SCISSORS_FALSE = 0,  /* pass --no-scissors to git-mailinfo */
+	SCISSORS_TRUE        /* pass --scissors to git-mailinfo */
+};
+
 struct am_state {
 	/* state directory path */
 	char *dir;
@@ -99,6 +105,7 @@ struct am_state {
 	int utf8;
 	int keep; /* enum keep_type */
 	int message_id;
+	int scissors; /* enum scissors_type */
 	const char *resolvemsg;
 	int rebasing;
 };
@@ -119,6 +126,8 @@ static void am_state_init(struct am_state *state, const char *dir)
 	state->utf8 = 1;
 
 	git_config_get_bool("am.messageid", &state->message_id);
+
+	state->scissors = SCISSORS_UNSET;
 }
 
 /**
@@ -394,6 +403,14 @@ static void am_load(struct am_state *state)
 	read_state_file(&sb, state, "messageid", 1);
 	state->message_id = !strcmp(sb.buf, "t");
 
+	read_state_file(&sb, state, "scissors", 1);
+	if (!strcmp(sb.buf, "t"))
+		state->scissors = SCISSORS_TRUE;
+	else if (!strcmp(sb.buf, "f"))
+		state->scissors = SCISSORS_FALSE;
+	else
+		state->scissors = SCISSORS_UNSET;
+
 	state->rebasing = !!file_exists(am_path(state, "rebasing"));
 
 	strbuf_release(&sb);
@@ -614,6 +631,22 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
 
 	write_file(am_path(state, "messageid"), 1, state->message_id ? "t" : "f");
 
+	switch (state->scissors) {
+	case SCISSORS_UNSET:
+		str = "";
+		break;
+	case SCISSORS_FALSE:
+		str = "f";
+		break;
+	case SCISSORS_TRUE:
+		str = "t";
+		break;
+	default:
+		die("BUG: invalid value for state->scissors");
+	}
+
+	write_file(am_path(state, "scissors"), 1, "%s", str);
+
 	if (state->rebasing)
 		write_file(am_path(state, "rebasing"), 1, "%s", "");
 	else
@@ -798,6 +831,19 @@ static int parse_mail(struct am_state *state, const char *mail)
 	if (state->message_id)
 		argv_array_push(&cp.args, "-m");
 
+	switch (state->scissors) {
+	case SCISSORS_UNSET:
+		break;
+	case SCISSORS_FALSE:
+		argv_array_push(&cp.args, "--no-scissors");
+		break;
+	case SCISSORS_TRUE:
+		argv_array_push(&cp.args, "--scissors");
+		break;
+	default:
+		die("BUG: invalid value for state->scissors");
+	}
+
 	argv_array_push(&cp.args, am_path(state, "msg"));
 	argv_array_push(&cp.args, am_path(state, "patch"));
 
@@ -1551,6 +1597,8 @@ int cmd_am(int argc, const char **argv, const char *prefix)
 		{ OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
 		  N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
 		  PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
+		OPT_BOOL('c', "scissors", &state.scissors,
+			N_("strip everything before a scissors line")),
 		OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
 			N_("format the patch(es) are in"),
 			parse_opt_patchformat),