From: Andre Noll <maan@tuebingen.mpg.de>
Date: Mon, 25 Nov 2024 20:55:43 +0000 (+0100)
Subject: com_select(): Support '-' to reactivate the previous mood/playlist.
X-Git-Url: http://git.tue.mpg.de/?a=commitdiff_plain;h=d09ca1da67f3f71b54ddd5f7d56d8d7cacf9d12c;p=paraslash.git

com_select(): Support '-' to reactivate the previous mood/playlist.

This adds two global variables to keep track of the previously active
mood or playlist. The select subcommand makes use of this information
if the argument is the special string '-'. The subcommand then follows
common Unix conventions and reactivates the previous mood or playlist.
---

diff --git a/afs.c b/afs.c
index 445d5871..ad1ececf 100644
--- a/afs.c
+++ b/afs.c
@@ -69,8 +69,8 @@ static int server_socket;
 static struct command_task command_task_struct;
 static struct signal_task *signal_task;
 
-static enum play_mode current_play_mode;
-static char *current_mop; /* mode or playlist specifier. NULL means dummy mood */
+static enum play_mode current_play_mode, previous_play_mode;
+static char *current_mop, *previous_mop; /* NULL means dummy mood */
 
 extern uint32_t afs_socket_cookie;
 
@@ -435,41 +435,56 @@ static int activate_mood_or_playlist(const char *arg, struct para_buffer *pb)
 {
 	enum play_mode mode;
 	int ret;
-	char *msg;
+	char *errmsg;
 
 	if (!arg) { /* load dummy mood */
-		ret = mood_load(NULL, NULL, &msg);
+		ret = mood_load(NULL, NULL, &errmsg);
 		mode = PLAY_MODE_MOOD;
+	} else if (!strcmp(arg, "-")) { /* load previous mop */
+		char *mop = previous_mop? previous_mop + 2 : NULL;
+		if (previous_play_mode == PLAY_MODE_MOOD)
+			ret = mood_load(mop, NULL, &errmsg);
+		else
+			ret = playlist_load(mop, NULL, &errmsg);
+		mode = previous_play_mode;
 	} else if (!strncmp(arg, "p/", 2)) {
-		ret = playlist_load(arg + 2, NULL, &msg);
+		ret = playlist_load(arg + 2, NULL, &errmsg);
 		mode = PLAY_MODE_PLAYLIST;
 	} else if (!strncmp(arg, "m/", 2)) {
-		ret = mood_load(arg + 2, NULL, &msg);
+		ret = mood_load(arg + 2, NULL, &errmsg);
 		mode = PLAY_MODE_MOOD;
 	} else {
 		ret = -ERRNO_TO_PARA_ERROR(EINVAL);
-		msg = make_message("%s: parse error\n", arg);
+		errmsg = make_message("%s: parse error\n", arg);
 	}
 	if (pb)
-		para_printf(pb, "%s", msg);
-	free(msg);
+		para_printf(pb, "%s", errmsg);
+	free(errmsg);
 	if (ret < 0)
 		return ret;
-	current_play_mode = mode;
 	/*
 	 * We get called with arg == current_mop from the signal dispatcher
 	 * after SIGHUP and from the error path of the select command to
-	 * re-select the current mood or playlist. In this case the assignment
-	 * to current_mop below would result in a use-after-free condition.
+	 * re-select the current mood or playlist. Don't update the four global
+	 * mop variables in these cases.
 	 */
 	if (arg != current_mop) {
-		free(current_mop);
-		current_mop = arg? para_strdup(arg) : NULL;
+		previous_play_mode = current_play_mode;
+		current_play_mode = mode;
+		if (arg && !strcmp(arg, "-")) {
+			char *tmp = current_mop;
+			current_mop = previous_mop;
+			previous_mop = tmp;
+		} else {
+			free(previous_mop);
+			previous_mop = current_mop;
+			current_mop = arg? para_strdup(arg) : NULL;
+		}
 	}
 	/* Notify the server about the mood/playlist change. */
 	mutex_lock(mmd_mutex);
-	strncpy(mmd->afs_mode_string, arg? arg: "dummy",
-		sizeof(mmd->afs_mode_string));
+	snprintf(mmd->afs_mode_string, sizeof(mmd->afs_mode_string) - 1,
+		"%s", current_mop? current_mop : "dummy");
 	mmd->afs_mode_string[sizeof(mmd->afs_mode_string) - 1] = '\0';
 	mmd->events++;
 	mutex_unlock(mmd_mutex);
@@ -959,6 +974,7 @@ out:
 	signal_shutdown(signal_task);
 	free_status_items();
 	free(current_mop);
+	free(previous_mop);
 	free_lpr();
 	if (ret < 0)
 		PARA_EMERG_LOG("%s\n", para_strerror(-ret));
diff --git a/m4/lls/server_cmd.suite.m4 b/m4/lls/server_cmd.suite.m4
index d694082b..f700339e 100644
--- a/m4/lls/server_cmd.suite.m4
+++ b/m4/lls/server_cmd.suite.m4
@@ -418,11 +418,13 @@ m4_include(`com_ll.m4')
 
 [subcommand select]
 	purpose = activate a mood or a playlist
-	non-opts-name = specifier/name
+	non-opts-name = mop
 	aux_info = AFS_READ | AFS_WRITE
 	[description]
-		The specifier is either 'm' or 'p' to indicate whether a playlist or
-		a mood should be activated. Example:
+		The argument is either the special string '-' to load the previous
+		mood or playlist, or of the form specifier/name. In the latter case
+		the specifier part of the argument is either 'm' or 'p' to indicate
+		whether a playlist or a mood should be activated. Example:
 
 			select m/foo