1 files changed, 78 insertions, 16 deletions

diff --git a/src/decoder_control.h b/src/decoder_control.h
index 566b153ee..9ecbde73e 100644
--- a/src/decoder_control.h
+++ b/src/decoder_control.h
@@ -67,6 +67,14 @@ struct decoder_control {
 	enum decoder_state state;
 	enum decoder_command command;
 
+	/**
+	 * The error that occurred in the decoder thread.  This
+	 * attribute is only valid if #state is #DECODE_STATE_ERROR.
+	 * The object must be freed when this object transitions to
+	 * any other state (usually #DECODE_STATE_START).
+	 */
+	GError *error;
+
 	bool quit;
 	bool seek_error;
 	bool seekable;
@@ -82,8 +90,11 @@ struct decoder_control {
 	 * The song currently being decoded.  This attribute is set by
 	 * the player thread, when it sends the #DECODE_COMMAND_START
 	 * command.
+	 *
+	 * This is a duplicate, and must be freed when this attribute
+	 * is cleared.
 	 */
-	const struct song *song;
+	struct song *song;
 
 	/**
 	 * The initial seek position (in milliseconds), e.g. to the
@@ -188,6 +199,50 @@ decoder_has_failed(const struct decoder_control *dc)
 	return dc->state == DECODE_STATE_ERROR;
 }
 
+/**
+ * Checks whether an error has occurred, and if so, returns a newly
+ * allocated copy of the #GError object.
+ *
+ * Caller must lock the object.
+ */
+static inline GError *
+dc_get_error(const struct decoder_control *dc)
+{
+	assert(dc != NULL);
+	assert(dc->command == DECODE_COMMAND_NONE);
+	assert(dc->state != DECODE_STATE_ERROR || dc->error != NULL);
+
+	return dc->state == DECODE_STATE_ERROR
+		? g_error_copy(dc->error)
+		: NULL;
+}
+
+/**
+ * Like dc_get_error(), but locks and unlocks the object.
+ */
+static inline GError *
+dc_lock_get_error(struct decoder_control *dc)
+{
+	decoder_lock(dc);
+	GError *error = dc_get_error(dc);
+	decoder_unlock(dc);
+	return error;
+}
+
+/**
+ * Clear the error condition and free the #GError object (if any).
+ *
+ * Caller must lock the object.
+ */
+static inline void
+dc_clear_error(struct decoder_control *dc)
+{
+	if (dc->state == DECODE_STATE_ERROR) {
+		g_error_free(dc->error);
+		dc->state = DECODE_STATE_STOP;
+	}
+}
+
 static inline bool
 decoder_lock_is_idle(struct decoder_control *dc)
 {
@@ -224,28 +279,35 @@ decoder_lock_has_failed(struct decoder_control *dc)
 	return ret;
 }
 
-static inline const struct song *
-decoder_current_song(const struct decoder_control *dc)
-{
-	switch (dc->state) {
-	case DECODE_STATE_STOP:
-	case DECODE_STATE_ERROR:
-		return NULL;
-
-	case DECODE_STATE_START:
-	case DECODE_STATE_DECODE:
-		return dc->song;
-	}
+/**
+ * Check if the specified song is currently being decoded.  If the
+ * decoder is not running currently (or being started), then this
+ * function returns false in any case.
+ *
+ * Caller must lock the object.
+ */
+gcc_pure
+bool
+decoder_is_current_song(const struct decoder_control *dc,
+			const struct song *song);
 
-	assert(false);
-	return NULL;
+gcc_pure
+static inline bool
+decoder_lock_is_current_song(struct decoder_control *dc,
+			     const struct song *song)
+{
+	decoder_lock(dc);
+	const bool result = decoder_is_current_song(dc, song);
+	decoder_unlock(dc);
+	return result;
 }
 
 /**
  * Start the decoder.
  *
  * @param the decoder
- * @param song the song to be decoded
+ * @param song the song to be decoded; the given instance will be
+ * owned and freed by the decoder
  * @param start_ms see #decoder_control
  * @param end_ms see #decoder_control
  * @param pipe the pipe which receives the decoded chunks (owned by