lyrics: added callback

Instead of letting our caller poll lyrics_result(), call it back as
soon as we have the result.

3 files changed, 56 insertions, 69 deletions

diff --git a/src/lyrics.c b/src/lyrics.c
index 917344701..7a6124b69 100644
--- a/src/lyrics.c
+++ b/src/lyrics.c
@@ -32,7 +32,8 @@ static GPtrArray *plugins;
 struct lyrics_loader {
 	char *artist, *title;
 
-	enum lyrics_loader_result result;
+	lyrics_callback_t callback;
+	void *callback_data;
 
 	guint next_plugin;
 
@@ -99,7 +100,7 @@ lyrics_eof(struct lyrics_loader *loader)
 
 		lyrics_next_plugin(loader);
 	} else {
-		loader->result = LYRICS_SUCCESS;
+		loader->callback(loader->data, loader->callback_data);
 	}
 }
 
@@ -112,7 +113,6 @@ lyrics_data(mpd_unused GIOChannel *source,
 	ssize_t nbytes;
 
 	assert(loader != NULL);
-	assert(loader->result = LYRICS_BUSY);
 	assert(loader->fd >= 0);
 	assert(loader->pid > 0);
 	assert(source == loader->channel);
@@ -134,6 +134,28 @@ lyrics_data(mpd_unused GIOChannel *source,
 	return TRUE;
 }
 
+/**
+ * This is a timer callback which calls the lyrics callback "some
+ * timer later".  This solves the problem that lyrics_load() may fail
+ * immediately, leaving its return value in an undefined state.
+ * Instead, install a timer which calls the lyrics callback in the
+ * moment after.
+ */
+static gboolean
+lyrics_delayed_fail(gpointer data)
+{
+	struct lyrics_loader *loader = data;
+
+	assert(loader != NULL);
+	assert(loader->fd < 0);
+	assert(loader->pid < 0);
+	assert(loader->data == NULL);
+
+	loader->callback(NULL, loader->callback_data);
+
+	return FALSE;
+}
+
 static int
 lyrics_start_plugin(struct lyrics_loader *loader, const char *plugin_path)
 {
@@ -141,7 +163,6 @@ lyrics_start_plugin(struct lyrics_loader *loader, const char *plugin_path)
 	pid_t pid;
 
 	assert(loader != NULL);
-	assert(loader->result == LYRICS_BUSY);
 	assert(loader->pid < 0);
 	assert(loader->fd < 0);
 	assert(loader->data == NULL);
@@ -198,7 +219,7 @@ lyrics_next_plugin(struct lyrics_loader *loader)
 
 	if (loader->next_plugin >= plugins->len) {
 		/* no plugins left */
-		loader->result = LYRICS_FAILED;
+		g_timeout_add(0, lyrics_delayed_fail, loader);
 		return;
 	}
 
@@ -206,13 +227,14 @@ lyrics_next_plugin(struct lyrics_loader *loader)
 	ret = lyrics_start_plugin(loader, plugin_path);
 	if (ret < 0) {
 		/* system error */
-		loader->result = LYRICS_FAILED;
+		g_timeout_add(0, lyrics_delayed_fail, loader);
 		return;
 	}
 }
 
 struct lyrics_loader *
-lyrics_load(const char *artist, const char *title)
+lyrics_load(const char *artist, const char *title,
+	    lyrics_callback_t callback, void *data)
 {
 	struct lyrics_loader *loader = g_new(struct lyrics_loader, 1);
 
@@ -224,7 +246,8 @@ lyrics_load(const char *artist, const char *title)
 
 	loader->artist = g_strdup(artist);
 	loader->title = g_strdup(title);
-	loader->result = LYRICS_BUSY;
+	loader->callback = callback;
+	loader->data = data;
 	loader->next_plugin = 0;
 	loader->pid = -1;
 	loader->fd = -1;
@@ -254,19 +277,3 @@ lyrics_free(struct lyrics_loader *loader)
 	if (loader->data != NULL)
 		g_string_free(loader->data, TRUE);
 }
-
-enum lyrics_loader_result
-lyrics_result(struct lyrics_loader *loader)
-{
-	return loader->result;
-}
-
-const GString *
-lyrics_get(struct lyrics_loader *loader)
-{
-	assert(loader->result == LYRICS_SUCCESS);
-	assert(loader->pid < 0);
-	assert(loader->data != NULL);
-
-	return loader->data;
-}
diff --git a/src/lyrics.h b/src/lyrics.h
index 34380c344..613ccb338 100644
--- a/src/lyrics.h
+++ b/src/lyrics.h
@@ -21,11 +21,7 @@
 
 #include <glib.h>
 
-enum lyrics_loader_result {
-	LYRICS_SUCCESS,
-	LYRICS_BUSY,
-	LYRICS_FAILED
-};
+typedef void (*lyrics_callback_t)(const GString *result, void *data);
 
 struct lyrics_loader;
 
@@ -34,15 +30,10 @@ void lyrics_init(void);
 void lyrics_deinit(void);
 
 struct lyrics_loader *
-lyrics_load(const char *artist, const char *title);
+lyrics_load(const char *artist, const char *title,
+	    lyrics_callback_t callback, void *callback_data);
 
 void
 lyrics_free(struct lyrics_loader *loader);
 
-enum lyrics_loader_result
-lyrics_result(struct lyrics_loader *loader);
-
-const GString *
-lyrics_get(struct lyrics_loader *loader);
-
 #endif
diff --git a/src/screen_lyrics.c b/src/screen_lyrics.c
index cfc658939..9b9ea03a2 100644
--- a/src/screen_lyrics.c
+++ b/src/screen_lyrics.c
@@ -76,15 +76,15 @@ screen_lyrics_clear(void)
 {
 	guint i;
 
-	assert(current.loader == NULL ||
-	       lyrics_result(current.loader) == LYRICS_SUCCESS);
-
 	for (i = 0; i < current.lines->len; ++i)
 		g_free(g_ptr_array_index(current.lines, i));
 
 	g_ptr_array_set_size(current.lines, 0);
 }
 
+static const char *
+list_callback(unsigned idx, int *highlight, void *data);
+
 static void
 screen_lyrics_set(const GString *str)
 {
@@ -122,32 +122,30 @@ screen_lyrics_set(const GString *str)
 
 	if (*p != 0)
 		g_ptr_array_add(current.lines, g_strdup(p));
+
+	/* paint new data */
+
+	if (get_cur_mode_id() == 104) { /* XXX don't use the literal number */
+		lw->clear = 1;
+		list_window_paint(lw, list_callback, NULL);
+		wrefresh(lw->w);
+
+		/* XXX repaint the screen title */
+	}
 }
 
-static int
-screen_lyrics_poll(void)
+static void
+screen_lyrics_callback(const GString *result, mpd_unused void *data)
 {
 	assert(current.loader != NULL);
 
-	switch (lyrics_result(current.loader)) {
-	case LYRICS_BUSY:
-		return 0;
-
-	case LYRICS_SUCCESS:
-		screen_lyrics_set(lyrics_get(current.loader));
-		lyrics_free(current.loader);
-		current.loader = NULL;
-		return 1;
-
-	case LYRICS_FAILED:
-		lyrics_free(current.loader);
-		current.loader = NULL;
+	if (result != NULL)
+		screen_lyrics_set(result);
+	else
 		screen_status_message (_("No lyrics"));
-		return -1;
-	}
 
-	assert(0);
-	return -1;
+	lyrics_free(current.loader);
+	current.loader = NULL;
 }
 
 static void
@@ -168,7 +166,8 @@ screen_lyrics_load(struct mpd_song *song)
 	strfsong(buffer, sizeof(buffer), "%title%", song);
 	current.title = g_strdup(buffer);
 
-	current.loader = lyrics_load(current.artist, current.title);
+	current.loader = lyrics_load(current.artist, current.title,
+				     screen_lyrics_callback, NULL);
 }
 
 static void lyrics_paint(screen_t *screen, mpdclient_t *c);
@@ -246,8 +245,6 @@ lyrics_open(mpd_unused screen_t *screen, mpdclient_t *c)
 {
 	if (c->song != NULL && c->song != current.song)
 		screen_lyrics_load(c->song);
-	else if (current.loader != NULL)
-		screen_lyrics_poll();
 }
 
 
@@ -292,14 +289,6 @@ lyrics_cmd(screen_t *screen, mpdclient_t *c, command_t cmd)
 		return 1;
 
 	switch(cmd) {
-	case CMD_SELECT:
-		/* XXX */
-		if (current.loader != NULL) {
-			int ret = screen_lyrics_poll();
-			if (ret != 0)
-				lyrics_paint(NULL, NULL);
-		}
-		return 1;
 	case CMD_INTERRUPT:
 		if (current.loader != NULL) {
 			screen_lyrics_abort();