filter/Internal: add method Reset()

src/filter/FilterInternal.hxx

@@ -52,6 +52,12 @@ public:
 		return out_audio_format;
 	}
 
+	/**
+	 * Reset the filter's state, e.g. drop/flush buffers.
+	 */
+	virtual void Reset() {
+	}
+
 	/**
 	 * Filters a block of PCM data.
 	 *
@@ -60,7 +66,7 @@ public:
 	 * @param src the input buffer
 	 * @return the destination buffer on success (will be
 	 * invalidated by deleting this object or the next FilterPCM()
-	 * call)
+	 * or Reset() call)
 	 */
 	virtual ConstBuffer<void> FilterPCM(ConstBuffer<void> src) = 0;
 };

src/filter/plugins/AutoConvertFilterPlugin.cxx

@@ -48,6 +48,13 @@ public:
 		:Filter(_filter->GetOutAudioFormat()),
 		 filter(std::move(_filter)), convert(std::move(_convert)) {}
 
+	void Reset() override {
+		filter->Reset();
+
+		if (convert)
+			convert->Reset();
+	}
+
 	ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override;
 };
 

src/filter/plugins/ChainFilterPlugin.cxx

@@ -61,6 +61,7 @@ public:
 	}
 
 	/* virtual methods from class Filter */
+	void Reset() override;
 	ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override;
 };
 
@@ -130,6 +131,13 @@ PreparedChainFilter::Open(AudioFormat &in_audio_format)
 	return chain.release();
 }
 
+void
+ChainFilter::Reset()
+{
+	for (auto &child : children)
+		child.filter->Reset();
+}
+
 ConstBuffer<void>
 ChainFilter::FilterPCM(ConstBuffer<void> src)
 {

src/filter/plugins/ConvertFilterPlugin.cxx

@@ -52,6 +52,10 @@ public:
 
 	void Set(const AudioFormat &_out_audio_format);
 
+	void Reset() override {
+		state.Reset();
+	}
+
 	ConstBuffer<void> FilterPCM(ConstBuffer<void> src) override;
 };