Add some comments.
Also, minor tweak to SurfaceTextureLayer.
Change-Id: If616d5ee4e8226dd0e16c5dbb0e0f80db553110e
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 8c2dade..f94a9ba 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -125,6 +125,22 @@
sp<ISurface> Layer::createSurface()
{
+ /*
+ * This class provides an implementation of BnSurface (the "native" or
+ * "remote" side of the Binder IPC interface ISurface), and mixes in
+ * LayerCleaner to ensure that mFlinger->onLayerDestroyed() is called for
+ * this layer when the BSurface is destroyed.
+ *
+ * The idea is to provide a handle to the Layer through ISurface that
+ * is cleaned up automatically when the last reference to the ISurface
+ * goes away. (The references will be held on the "proxy" side, while
+ * the Layer exists on the "native" side.)
+ *
+ * The Layer has a reference to an instance of SurfaceFlinger's variant
+ * of GLConsumer, which holds a reference to the BufferQueue. The
+ * getSurfaceTexture() call returns a Binder interface reference for
+ * the producer interface of the buffer queue associated with the Layer.
+ */
class BSurface : public BnSurface, public LayerCleaner {
wp<const Layer> mOwner;
virtual sp<IGraphicBufferProducer> getSurfaceTexture() const {
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 2d4afc4..ef829ed 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -47,11 +47,19 @@
// ---------------------------------------------------------------------------
+/*
+ * The Layer class is essentially a LayerBase combined with a BufferQueue.
+ * A new BufferQueue and a new SurfaceFlingerConsumer are created when the
+ * Layer is first referenced.
+ *
+ * This also implements onFrameAvailable(), which notifies SurfaceFlinger
+ * that new data has arrived.
+ */
class Layer : public LayerBaseClient,
public SurfaceFlingerConsumer::FrameAvailableListener
{
public:
- Layer(SurfaceFlinger* flinger, const sp<Client>& client);
+ Layer(SurfaceFlinger* flinger, const sp<Client>& client);
virtual ~Layer();
virtual const char* getTypeId() const { return "Layer"; }
@@ -102,8 +110,9 @@
virtual void clearStats();
private:
- friend class SurfaceTextureLayer;
+ // Creates an instance of ISurface for this Layer.
virtual sp<ISurface> createSurface();
+
uint32_t getEffectiveUsage(uint32_t usage) const;
bool isCropped() const;
Rect computeBufferCrop() const;
diff --git a/services/surfaceflinger/LayerBase.h b/services/surfaceflinger/LayerBase.h
index 7a9471e..47473e7 100644
--- a/services/surfaceflinger/LayerBase.h
+++ b/services/surfaceflinger/LayerBase.h
@@ -49,6 +49,18 @@
// ---------------------------------------------------------------------------
+/*
+ * Layers are rectangular graphic entities, internal to SurfaceFlinger.
+ * They have properties including width, height, Z-depth, and 2D
+ * transformations (chiefly translation and 90-degree rotations).
+ *
+ * Layers are organized into "layer stacks". Each layer is a member of
+ * exactly one layer stack, identified by an integer in Layer::State. A
+ * given layer stack may appear on more than one display.
+ *
+ * Notable subclasses (below LayerBaseClient) include Layer, LayerDim, and
+ * LayerScreenshot.
+ */
class LayerBase : virtual public RefBase
{
static int32_t sSequence;
@@ -308,16 +320,27 @@
// ---------------------------------------------------------------------------
+/*
+ * This adds some additional fields and methods to support some Binder IPC
+ * interactions. In particular, the LayerBaseClient's lifetime can be
+ * managed by references to an ISurface object in another process.
+ */
class LayerBaseClient : public LayerBase
{
public:
- LayerBaseClient(SurfaceFlinger* flinger, const sp<Client>& client);
+ LayerBaseClient(SurfaceFlinger* flinger, const sp<Client>& client);
- virtual ~LayerBaseClient();
+ virtual ~LayerBaseClient();
- sp<ISurface> getSurface();
- wp<IBinder> getSurfaceBinder() const;
- virtual wp<IBinder> getSurfaceTextureBinder() const;
+ // Creates an ISurface associated with this object. This may only be
+ // called once (see also getSurfaceBinder()).
+ sp<ISurface> getSurface();
+
+ // Returns the Binder object for the ISurface associated with
+ // this object.
+ wp<IBinder> getSurfaceBinder() const;
+
+ virtual wp<IBinder> getSurfaceTextureBinder() const;
virtual sp<LayerBaseClient> getLayerBaseClient() const {
return const_cast<LayerBaseClient*>(this); }
@@ -330,6 +353,10 @@
virtual void dump(String8& result, char* scratch, size_t size) const;
virtual void shortDump(String8& result, char* scratch, size_t size) const;
+ /*
+ * Trivial class, used to ensure that mFlinger->onLayerDestroyed(mLayer)
+ * is called.
+ */
class LayerCleaner {
sp<SurfaceFlinger> mFlinger;
wp<LayerBaseClient> mLayer;
@@ -344,8 +371,13 @@
virtual sp<ISurface> createSurface();
mutable Mutex mLock;
+
+ // Set to true if an ISurface has been associated with this object.
mutable bool mHasSurface;
+
+ // The ISurface's Binder object, set by getSurface().
wp<IBinder> mClientSurfaceBinder;
+
const wp<Client> mClientRef;
// only read
const uint32_t mIdentity;
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index f0e5719..46476f9 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -575,13 +575,18 @@
Mutex::Autolock _l(mStateLock);
sp<IBinder> surfaceTextureBinder(bufferProducer->asBinder());
- // Check the visible layer list for the ISurface
+ // We want to determine whether the IGraphicBufferProducer was created by
+ // SurfaceFlinger. Check to see if we can find it in the layer list.
const LayerVector& currentLayers = mCurrentState.layersSortedByZ;
size_t count = currentLayers.size();
for (size_t i=0 ; i<count ; i++) {
const sp<LayerBase>& layer(currentLayers[i]);
sp<LayerBaseClient> lbc(layer->getLayerBaseClient());
if (lbc != NULL) {
+ // If this is an instance of Layer (as opposed to, say, LayerDim),
+ // we will get the consumer interface of SurfaceFlingerConsumer's
+ // BufferQueue. If it's the same Binder object as the graphic
+ // buffer producer interface, return success.
wp<IBinder> lbcBinder = lbc->getSurfaceTextureBinder();
if (lbcBinder == surfaceTextureBinder) {
return true;
diff --git a/services/surfaceflinger/SurfaceTextureLayer.cpp b/services/surfaceflinger/SurfaceTextureLayer.cpp
index 0b638b4..395c8c8 100644
--- a/services/surfaceflinger/SurfaceTextureLayer.cpp
+++ b/services/surfaceflinger/SurfaceTextureLayer.cpp
@@ -20,7 +20,6 @@
#include <utils/Errors.h>
-#include "Layer.h"
#include "SurfaceTextureLayer.h"
namespace android {
diff --git a/services/surfaceflinger/SurfaceTextureLayer.h b/services/surfaceflinger/SurfaceTextureLayer.h
index 8baa8d2..a75ccf4 100644
--- a/services/surfaceflinger/SurfaceTextureLayer.h
+++ b/services/surfaceflinger/SurfaceTextureLayer.h
@@ -29,12 +29,17 @@
class Layer;
+/*
+ * This is a thin wrapper around BufferQueue, used by the Layer class.
+ */
class SurfaceTextureLayer : public BufferQueue
{
public:
SurfaceTextureLayer();
~SurfaceTextureLayer();
+ // After calling the superclass connect(), set or clear synchronous
+ // mode appropriately for the specified API.
virtual status_t connect(int api, QueueBufferOutput* output);
};