decoder/API: move part of decoder_check_cancel_read() into class DecoderBridge

src/decoder/Bridge.cxx

@@ -43,6 +43,26 @@ DecoderBridge::~DecoderBridge()
 	delete decoder_tag;
 }
 
+bool
+DecoderBridge::CheckCancelRead() const
+{
+	if (error)
+		/* this translates to DecoderCommand::STOP */
+		return true;
+
+	if (dc.command == DecoderCommand::NONE)
+		return false;
+
+	/* ignore the SEEK command during initialization, the plugin
+	   should handle that after it has initialized successfully */
+	if (dc.command == DecoderCommand::SEEK &&
+	    (dc.state == DecoderState::START || seeking ||
+	     initial_seek_running))
+		return false;
+
+	return true;
+}
+
 /**
  * All chunks are full of decoded data; wait for the player to free
  * one.

src/decoder/Bridge.hxx

@@ -107,6 +107,15 @@ public:
 
 	~DecoderBridge();
 
+	/**
+	 * Should be read operation be cancelled?  That is the case when the
+	 * player thread has sent a command such as "STOP".
+	 *
+	 * Caller must lock the #DecoderControl object.
+	 */
+	gcc_pure
+	bool CheckCancelRead() const;
+
 	/**
 	 * Returns the current chunk the decoder writes to, or allocates a new
 	 * chunk if there is none.

src/decoder/DecoderAPI.cxx

@@ -264,25 +264,7 @@ gcc_pure
 static inline bool
 decoder_check_cancel_read(const DecoderBridge *bridge)
 {
-	if (bridge == nullptr)
+	return bridge != nullptr && bridge->CheckCancelRead();
-		return false;
-
-	if (bridge->error)
-		/* this translates to DecoderCommand::STOP */
-		return true;
-
-	const DecoderControl &dc = bridge->dc;
-	if (dc.command == DecoderCommand::NONE)
-		return false;
-
-	/* ignore the SEEK command during initialization, the plugin
-	   should handle that after it has initialized successfully */
-	if (dc.command == DecoderCommand::SEEK &&
-	    (dc.state == DecoderState::START || bridge->seeking ||
-	     bridge->initial_seek_running))
-		return false;
-
-	return true;
 }
 
 size_t