Making classers.del safer + FilterGraph now stores its FilterContexts…

… to remove them from classers properly

bit_stream_filter_context.go

@@ -62,12 +62,14 @@ func (bsfc *BitStreamFilterContext) ReceivePacket(p *Packet) error {
 func (bsfc *BitStreamFilterContext) Free() {
 	if bsfc.c != nil {
 		// Make sure to clone the classer before freeing the object since
-		// the C free method resets the pointer
+		// the C free method may reset the pointer
 		c := newClonedClasser(bsfc)
 		C.av_bsf_free(&bsfc.c)
 		// Make sure to remove from classers after freeing the object since
 		// the C free method may use methods needing the classer
-		classers.del(c)
+		if c != nil {
+			classers.del(c)
+		}
 	}
 }
 

class_test.go

@@ -28,7 +28,8 @@ func TestClass(t *testing.T) {
 
 func TestClassers(t *testing.T) {
 	cl := len(classers.p)
-	f := AllocFilterGraph()
+	f1 := AllocFilterGraph()
+	f2 := AllocFilterGraph()
 	c := FindDecoder(CodecIDMjpeg)
 	require.NotNil(t, c)
 	bf := FindBitStreamFilterByName("null")
@@ -39,7 +40,9 @@ func TestClassers(t *testing.T) {
 	require.NotNil(t, cc)
 	bufferSink := FindFilterByName("buffersink")
 	require.NotNil(t, bufferSink)
-	fc, err := f.NewFilterContext(bufferSink, "filter_out", nil)
+	fc1, err := f1.NewFilterContext(bufferSink, "filter_out", nil)
+	require.NoError(t, err)
+	_, err = f2.NewFilterContext(bufferSink, "filter_out", nil)
 	require.NoError(t, err)
 	fmc1 := AllocFormatContext()
 	fmc2 := AllocFormatContext()
@@ -53,15 +56,16 @@ func TestClassers(t *testing.T) {
 	ssc, err := CreateSoftwareScaleContext(1, 1, PixelFormatRgba, 2, 2, PixelFormatRgba, NewSoftwareScaleContextFlags())
 	require.NoError(t, err)
 
-	require.Equal(t, cl+10, len(classers.p))
-	v, ok := classers.get(unsafe.Pointer(f.c))
+	require.Equal(t, cl+12, len(classers.p))
+	v, ok := classers.get(unsafe.Pointer(f1.c))
 	require.True(t, ok)
-	require.Equal(t, f, v)
+	require.Equal(t, f1, v)
 
 	bfc.Free()
 	cc.Free()
-	fc.Free()
-	f.Free()
+	fc1.Free()
+	f1.Free()
+	f2.Free()
 	fmc1.Free()
 	fmc2.CloseInput()
 	require.NoError(t, ic1.Close())

codec_context.go

@@ -45,12 +45,14 @@ func (cc *CodecContext) Free() {
 	}
 	if cc.c != nil {
 		// Make sure to clone the classer before freeing the object since
-		// the C free method resets the pointer
+		// the C free method may reset the pointer
 		c := newClonedClasser(cc)
 		C.avcodec_free_context(&cc.c)
 		// Make sure to remove from classers after freeing the object since
 		// the C free method may use methods needing the classer
-		classers.del(c)
+		if c != nil {
+			classers.del(c)
+		}
 	}
 }
 

filter_context.go

@@ -27,10 +27,15 @@ func newFilterContext(c *C.AVFilterContext) *FilterContext {
 var _ Classer = (*FilterContext)(nil)
 
 func (fc *FilterContext) Free() {
+	// Make sure to clone the classer before freeing the object since
+	// the C free method may reset the pointer
+	c := newClonedClasser(fc)
 	C.avfilter_free(fc.c)
 	// Make sure to remove from classers after freeing the object since
 	// the C free method may use methods needing the classer
-	classers.del(fc)
+	if c != nil {
+		classers.del(c)
+	}
 }
 
 func (fc *FilterContext) BuffersrcAddFrame(f *Frame, fs BuffersrcFlags) error {

filter_graph.go

@@ -10,6 +10,8 @@ import (
 // https://github.com/FFmpeg/FFmpeg/blob/n5.0/libavfilter/avfilter.h#L861
 type FilterGraph struct {
 	c *C.AVFilterGraph
+	// We need to store filter contexts to clean classer once filter graph is freed
+	fcs []*FilterContext
 }
 
 func newFilterGraphFromC(c *C.AVFilterGraph) *FilterGraph {
@@ -30,12 +32,23 @@ func AllocFilterGraph() *FilterGraph {
 func (g *FilterGraph) Free() {
 	if g.c != nil {
 		// Make sure to clone the classer before freeing the object since
-		// the C free method resets the pointer
+		// the C free method may reset the pointer
 		c := newClonedClasser(g)
+		var cfcs []Classer
+		for _, fc := range g.fcs {
+			cfcs = append(cfcs, newClonedClasser(fc))
+		}
 		C.avfilter_graph_free(&g.c)
 		// Make sure to remove from classers after freeing the object since
 		// the C free method may use methods needing the classer
-		classers.del(c)
+		for _, cfc := range cfcs {
+			if cfc != nil {
+				classers.del(cfc)
+			}
+		}
+		if c != nil {
+			classers.del(c)
+		}
 	}
 }
 
@@ -85,7 +98,9 @@ func (g *FilterGraph) NewFilterContext(f *Filter, name string, args FilterArgs)
 	if err := newError(C.avfilter_graph_create_filter(&c, f.c, cn, ca, nil, g.c)); err != nil {
 		return nil, err
 	}
-	return newFilterContext(c), nil
+	fc := newFilterContext(c)
+	g.fcs = append(g.fcs, fc)
+	return fc, nil
 }
 
 func (g *FilterGraph) Parse(content string, inputs, outputs *FilterInOut) error {

format_context.go

@@ -51,10 +51,15 @@ func AllocOutputFormatContext(of *OutputFormat, formatName, filename string) (*F
 }
 
 func (fc *FormatContext) Free() {
+	// Make sure to clone the classer before freeing the object since
+	// the C free method may reset the pointer
+	c := newClonedClasser(fc)
 	C.avformat_free_context(fc.c)
 	// Make sure to remove from classers after freeing the object since
 	// the C free method may use methods needing the classer
-	classers.del(fc)
+	if c != nil {
+		classers.del(c)
+	}
 }
 
 func (fc *FormatContext) BitRate() int64 {
@@ -194,18 +199,23 @@ func (fc *FormatContext) OpenInput(url string, fmt *InputFormat, d *Dictionary)
 }
 
 func (fc *FormatContext) CloseInput() {
-	pb := fc.Pb()
 	if fc.c != nil {
 		// Make sure to clone the classer before freeing the object since
-		// the C free method resets the pointer
+		// the C free method may reset the pointer
 		c := newClonedClasser(fc)
+		var cpb Classer
+		if pb := fc.Pb(); pb != nil {
+			cpb = newClonedClasser(pb)
+		}
 		C.avformat_close_input(&fc.c)
 		// Make sure to remove from classers after freeing the object since
 		// the C free method may use methods needing the classer
-		if pb != nil {
-			classers.del(pb)
+		if cpb != nil {
+			classers.del(cpb)
+		}
+		if c != nil {
+			classers.del(c)
 		}
-		classers.del(c)
 	}
 }
 

io_context.go

@@ -124,14 +124,16 @@ func (ic *IOContext) Class() *Class {
 func (ic *IOContext) Close() error {
 	if ic.c != nil {
 		// Make sure to clone the classer before freeing the object since
-		// the C free method resets the pointer
+		// the C free method may reset the pointer
 		c := newClonedClasser(ic)
 		if err := newError(C.avio_closep(&ic.c)); err != nil {
 			return err
 		}
 		// Make sure to remove from classers after freeing the object since
 		// the C free method may use methods needing the classer
-		classers.del(c)
+		if c != nil {
+			classers.del(c)
+		}
 	}
 	return nil
 }
@@ -146,12 +148,14 @@ func (ic *IOContext) Free() {
 			ic.handlerID = nil
 		}
 		// Make sure to clone the classer before freeing the object since
-		// the C free method resets the pointer
+		// the C free method may reset the pointer
 		c := newClonedClasser(ic)
 		C.avio_context_free(&ic.c)
 		// Make sure to remove from classers after freeing the object since
 		// the C free method may use methods needing the classer
-		classers.del(c)
+		if c != nil {
+			classers.del(c)
+		}
 	}
 	return
 }

software_scale_context.go

@@ -66,7 +66,9 @@ func (ssc *SoftwareScaleContext) Free() {
 	C.sws_freeContext(ssc.c)
 	// Make sure to remove from classers after freeing the object since
 	// the C free method may use methods needing the classer
-	classers.del(c)
+	if c != nil {
+		classers.del(c)
+	}
 }
 
 var _ Classer = (*SoftwareScaleContext)(nil)