libgui: Add generation numbers to BufferQueue

This change allows producers to set a generation number on a
BufferQueue. This number will be embedded in any new GraphicBuffers
created in that BufferQueue, and attempts to attach buffers which have
a different generation number will fail.

It also plumbs the setGenerationNumber method through Surface, with the
additional effect that any buffers attached to the Surface after
setting a new generation number will automatically be updated with the
new number (as opposed to failing, as would happen on through IGBP).

Bug: 20923096
Change-Id: I32bf726b035f99c3e5834beaf76afb9f01adcbc2

18 files changed, 199 insertions, 16 deletions

diff --git a/include/gui/BufferQueueCore.h b/include/gui/BufferQueueCore.h
index d7686ec..99134ea 100644
--- a/include/gui/BufferQueueCore.h
+++ b/include/gui/BufferQueueCore.h
@@ -275,6 +275,11 @@ private:
     // buffer as the number of frames that have elapsed since it was last queued
     uint64_t mBufferAge;
 
+    // mGenerationNumber stores the current generation number of the attached
+    // producer. Any attempt to attach a buffer with a different generation
+    // number will fail.
+    uint32_t mGenerationNumber;
+
 }; // class BufferQueueCore
 
 } // namespace android
diff --git a/include/gui/BufferQueueProducer.h b/include/gui/BufferQueueProducer.h
index ed660fb..afa7eb1 100644
--- a/include/gui/BufferQueueProducer.h
+++ b/include/gui/BufferQueueProducer.h
@@ -175,6 +175,9 @@ public:
     // See IGraphicBufferProducer::allowAllocation
     virtual status_t allowAllocation(bool allow);
 
+    // See IGraphicBufferProducer::setGenerationNumber
+    virtual status_t setGenerationNumber(uint32_t generationNumber);
+
 private:
     // This is required by the IBinder::DeathRecipient interface
     virtual void binderDied(const wp<IBinder>& who);
diff --git a/include/gui/IGraphicBufferConsumer.h b/include/gui/IGraphicBufferConsumer.h
index 6363a3a..60ec9cc 100644
--- a/include/gui/IGraphicBufferConsumer.h
+++ b/include/gui/IGraphicBufferConsumer.h
@@ -110,7 +110,8 @@ public:
     // will be deallocated as stale.
     //
     // Return of a value other than NO_ERROR means an error has occurred:
-    // * BAD_VALUE - outSlot or buffer were NULL
+    // * BAD_VALUE - outSlot or buffer were NULL, or the generation number of
+    //               the buffer did not match the buffer queue.
     // * INVALID_OPERATION - cannot attach the buffer because it would cause too
     //                       many buffers to be acquired.
     // * NO_MEMORY - no free slots available
diff --git a/include/gui/IGraphicBufferProducer.h b/include/gui/IGraphicBufferProducer.h
index 5c50b2b..4ca4cd5 100644
--- a/include/gui/IGraphicBufferProducer.h
+++ b/include/gui/IGraphicBufferProducer.h
@@ -218,8 +218,9 @@ public:
     //
     // Return of a negative value means an error has occurred:
     // * NO_INIT - the buffer queue has been abandoned.
-    // * BAD_VALUE - outSlot or buffer were NULL or invalid combination of
-    //               async mode and buffer count override.
+    // * BAD_VALUE - outSlot or buffer were NULL, invalid combination of
+    //               async mode and buffer count override, or the generation
+    //               number of the buffer did not match the buffer queue.
     // * INVALID_OPERATION - cannot attach the buffer because it would cause
     //                       too many buffers to be dequeued, either because
     //                       the producer already has a single buffer dequeued
@@ -470,6 +471,15 @@ public:
     // eligible slot is available, dequeueBuffer will block or return an error
     // as usual.
     virtual status_t allowAllocation(bool allow) = 0;
+
+    // Sets the current generation number of the BufferQueue.
+    //
+    // This generation number will be inserted into any buffers allocated by the
+    // BufferQueue, and any attempts to attach a buffer with a different
+    // generation number will fail. Buffers already in the queue are not
+    // affected and will retain their current generation number. The generation
+    // number defaults to 0.
+    virtual status_t setGenerationNumber(uint32_t generationNumber) = 0;
 };
 
 // ----------------------------------------------------------------------------
diff --git a/include/gui/Surface.h b/include/gui/Surface.h
index fd6d48c..261b07c 100644
--- a/include/gui/Surface.h
+++ b/include/gui/Surface.h
@@ -101,6 +101,11 @@ public:
      */
     void allocateBuffers();
 
+    /* Sets the generation number on the IGraphicBufferProducer and updates the
+     * generation number on any buffers attached to the Surface after this call.
+     * See IGBP::setGenerationNumber for more information. */
+    status_t setGenerationNumber(uint32_t generationNumber);
+
 protected:
     virtual ~Surface();
 
@@ -305,6 +310,10 @@ private:
     // When a non-CPU producer is attached, this reflects the surface damage
     // (the change since the previous frame) passed in by the producer.
     Region mDirtyRegion;
+
+    // Stores the current generation number. See setGenerationNumber and
+    // IGraphicBufferProducer::setGenerationNumber for more information.
+    uint32_t mGenerationNumber;
 };
 
 }; // namespace android
diff --git a/include/ui/GraphicBuffer.h b/include/ui/GraphicBuffer.h
index f91d192..3da720f 100644
--- a/include/ui/GraphicBuffer.h
+++ b/include/ui/GraphicBuffer.h
@@ -94,6 +94,11 @@ public:
     Rect getBounds() const              { return Rect(width, height); }
     uint64_t getId() const              { return mId; }
 
+    uint32_t getGenerationNumber() const { return mGenerationNumber; }
+    void setGenerationNumber(uint32_t generation) {
+        mGenerationNumber = generation;
+    }
+
     status_t reallocate(uint32_t inWidth, uint32_t inHeight,
             PixelFormat inFormat, uint32_t inUsage);
 
@@ -166,6 +171,11 @@ private:
     sp<ANativeWindowBuffer> mWrappedBuffer;
 
     uint64_t mId;
+
+    // Stores the generation number of this buffer. If this number does not
+    // match the BufferQueue's internal generation number (set through
+    // IGBP::setGenerationNumber), attempts to attach the buffer will fail.
+    uint32_t mGenerationNumber;
 };
 
 }; // namespace android
diff --git a/libs/gui/BufferQueueConsumer.cpp b/libs/gui/BufferQueueConsumer.cpp
index 4174676..ae796b1 100644
--- a/libs/gui/BufferQueueConsumer.cpp
+++ b/libs/gui/BufferQueueConsumer.cpp
@@ -248,6 +248,13 @@ status_t BufferQueueConsumer::attachBuffer(int* outSlot,
         return INVALID_OPERATION;
     }
 
+    if (buffer->getGenerationNumber() != mCore->mGenerationNumber) {
+        BQ_LOGE("attachBuffer: generation number mismatch [buffer %u] "
+                "[queue %u]", buffer->getGenerationNumber(),
+                mCore->mGenerationNumber);
+        return BAD_VALUE;
+    }
+
     // Find a free slot to put the buffer into
     int found = BufferQueueCore::INVALID_BUFFER_SLOT;
     if (!mCore->mFreeSlots.empty()) {
diff --git a/libs/gui/BufferQueueCore.cpp b/libs/gui/BufferQueueCore.cpp
index e784644..851a396 100644
--- a/libs/gui/BufferQueueCore.cpp
+++ b/libs/gui/BufferQueueCore.cpp
@@ -71,7 +71,8 @@ BufferQueueCore::BufferQueueCore(const sp<IGraphicBufferAlloc>& allocator) :
     mIsAllocating(false),
     mIsAllocatingCondition(),
     mAllowAllocation(true),
-    mBufferAge(0)
+    mBufferAge(0),
+    mGenerationNumber(0)
 {
     if (allocator == NULL) {
         sp<ISurfaceComposer> composer(ComposerService::getComposerService());
diff --git a/libs/gui/BufferQueueProducer.cpp b/libs/gui/BufferQueueProducer.cpp
index e318484..73d4261 100644
--- a/libs/gui/BufferQueueProducer.cpp
+++ b/libs/gui/BufferQueueProducer.cpp
@@ -383,6 +383,7 @@ status_t BufferQueueProducer::dequeueBuffer(int *outSlot,
                 return NO_INIT;
             }
 
+            graphicBuffer->setGenerationNumber(mCore->mGenerationNumber);
             mSlots[*outSlot].mGraphicBuffer = graphicBuffer;
         } // Autolock scope
     }
@@ -498,6 +499,13 @@ status_t BufferQueueProducer::attachBuffer(int* outSlot,
     Mutex::Autolock lock(mCore->mMutex);
     mCore->waitWhileAllocatingLocked();
 
+    if (buffer->getGenerationNumber() != mCore->mGenerationNumber) {
+        BQ_LOGE("attachBuffer: generation number mismatch [buffer %u] "
+                "[queue %u]", buffer->getGenerationNumber(),
+                mCore->mGenerationNumber);
+        return BAD_VALUE;
+    }
+
     status_t returnFlags = NO_ERROR;
     int found;
     // TODO: Should we provide an async flag to attachBuffer? It seems
@@ -1072,6 +1080,15 @@ status_t BufferQueueProducer::allowAllocation(bool allow) {
     return NO_ERROR;
 }
 
+status_t BufferQueueProducer::setGenerationNumber(uint32_t generationNumber) {
+    ATRACE_CALL();
+    BQ_LOGV("setGenerationNumber: %u", generationNumber);
+
+    Mutex::Autolock lock(mCore->mMutex);
+    mCore->mGenerationNumber = generationNumber;
+    return NO_ERROR;
+}
+
 void BufferQueueProducer::binderDied(const wp<android::IBinder>& /* who */) {
     // If we're here, it means that a producer we were connected to died.
     // We're guaranteed that we are still connected to it because we remove
diff --git a/libs/gui/IGraphicBufferProducer.cpp b/libs/gui/IGraphicBufferProducer.cpp
index 7093ffa..cfe726b 100644
--- a/libs/gui/IGraphicBufferProducer.cpp
+++ b/libs/gui/IGraphicBufferProducer.cpp
@@ -47,6 +47,7 @@ enum {
     SET_SIDEBAND_STREAM,
     ALLOCATE_BUFFERS,
     ALLOW_ALLOCATION,
+    SET_GENERATION_NUMBER,
 };
 
 class BpGraphicBufferProducer : public BpInterface<IGraphicBufferProducer>
@@ -284,6 +285,17 @@ public:
         result = reply.readInt32();
         return result;
     }
+
+    virtual status_t setGenerationNumber(uint32_t generationNumber) {
+        Parcel data, reply;
+        data.writeInterfaceToken(IGraphicBufferProducer::getInterfaceDescriptor());
+        data.writeUint32(generationNumber);
+        status_t result = remote()->transact(SET_GENERATION_NUMBER, data, &reply);
+        if (result == NO_ERROR) {
+            result = reply.readInt32();
+        }
+        return result;
+    }
 };
 
 // Out-of-line virtual method definition to trigger vtable emission in this
@@ -448,6 +460,13 @@ status_t BnGraphicBufferProducer::onTransact(
             reply->writeInt32(result);
             return NO_ERROR;
         }
+        case SET_GENERATION_NUMBER: {
+            CHECK_INTERFACE(IGraphicBufferProducer, data, reply);
+            uint32_t generationNumber = data.readUint32();
+            status_t result = setGenerationNumber(generationNumber);
+            reply->writeInt32(result);
+            return NO_ERROR;
+        }
     }
     return BBinder::onTransact(code, data, reply, flags);
 }
diff --git a/libs/gui/Surface.cpp b/libs/gui/Surface.cpp
index 04ac0f4..aeb56e0 100644
--- a/libs/gui/Surface.cpp
+++ b/libs/gui/Surface.cpp
@@ -42,7 +42,8 @@ namespace android {
 Surface::Surface(
         const sp<IGraphicBufferProducer>& bufferProducer,
         bool controlledByApp)
-    : mGraphicBufferProducer(bufferProducer)
+    : mGraphicBufferProducer(bufferProducer),
+      mGenerationNumber(0)
 {
     // Initialize the ANativeWindow function pointers.
     ANativeWindow::setSwapInterval  = hook_setSwapInterval;
@@ -102,6 +103,14 @@ void Surface::allocateBuffers() {
             reqHeight, mReqFormat, mReqUsage);
 }
 
+status_t Surface::setGenerationNumber(uint32_t generation) {
+    status_t result = mGraphicBufferProducer->setGenerationNumber(generation);
+    if (result == NO_ERROR) {
+        mGenerationNumber = generation;
+    }
+    return result;
+}
+
 int Surface::hook_setSwapInterval(ANativeWindow* window, int interval) {
     Surface* c = getSelf(window);
     return c->setSwapInterval(interval);
@@ -698,11 +707,14 @@ int Surface::attachBuffer(ANativeWindowBuffer* buffer)
     Mutex::Autolock lock(mMutex);
 
     sp<GraphicBuffer> graphicBuffer(static_cast<GraphicBuffer*>(buffer));
+    uint32_t priorGeneration = graphicBuffer->mGenerationNumber;
+    graphicBuffer->mGenerationNumber = mGenerationNumber;
     int32_t attachedSlot = -1;
     status_t result = mGraphicBufferProducer->attachBuffer(
             &attachedSlot, graphicBuffer);
     if (result != NO_ERROR) {
         ALOGE("attachBuffer: IGraphicBufferProducer call failed (%d)", result);
+        graphicBuffer->mGenerationNumber = priorGeneration;
         return result;
     }
     mSlots[attachedSlot].buffer = graphicBuffer;
diff --git a/libs/gui/tests/BufferQueue_test.cpp b/libs/gui/tests/BufferQueue_test.cpp
index 1584fef..3d1139d 100644
--- a/libs/gui/tests/BufferQueue_test.cpp
+++ b/libs/gui/tests/BufferQueue_test.cpp
@@ -402,4 +402,46 @@ TEST_F(BufferQueueTest, TestDisallowingAllocation) {
             WIDTH * 2, HEIGHT * 2, 0, GRALLOC_USAGE_SW_WRITE_OFTEN));
 }
 
+TEST_F(BufferQueueTest, TestGenerationNumbers) {
+    createBufferQueue();
+    sp<DummyConsumer> dc(new DummyConsumer);
+    ASSERT_EQ(OK, mConsumer->consumerConnect(dc, true));
+    IGraphicBufferProducer::QueueBufferOutput output;
+    ASSERT_EQ(OK, mProducer->connect(new DummyProducerListener,
+            NATIVE_WINDOW_API_CPU, true, &output));
+
+    ASSERT_EQ(OK, mProducer->setGenerationNumber(1));
+
+    // Get one buffer to play with
+    int slot;
+    sp<Fence> fence;
+    ASSERT_EQ(IGraphicBufferProducer::BUFFER_NEEDS_REALLOCATION,
+            mProducer->dequeueBuffer(&slot, &fence, false, 0, 0, 0, 0));
+
+    sp<GraphicBuffer> buffer;
+    ASSERT_EQ(OK, mProducer->requestBuffer(slot, &buffer));
+
+    // Ensure that the generation number we set propagates to allocated buffers
+    ASSERT_EQ(1U, buffer->getGenerationNumber());
+
+    ASSERT_EQ(OK, mProducer->detachBuffer(slot));
+
+    ASSERT_EQ(OK, mProducer->setGenerationNumber(2));
+
+    // These should fail, since we've changed the generation number on the queue
+    int outSlot;
+    ASSERT_EQ(BAD_VALUE, mProducer->attachBuffer(&outSlot, buffer));
+    ASSERT_EQ(BAD_VALUE, mConsumer->attachBuffer(&outSlot, buffer));
+
+    buffer->setGenerationNumber(2);
+
+    // This should succeed now that we've changed the buffer's generation number
+    ASSERT_EQ(OK, mProducer->attachBuffer(&outSlot, buffer));
+
+    ASSERT_EQ(OK, mProducer->detachBuffer(outSlot));
+
+    // This should also succeed with the new generation number
+    ASSERT_EQ(OK, mConsumer->attachBuffer(&outSlot, buffer));
+}
+
 } // namespace android
diff --git a/libs/gui/tests/Surface_test.cpp b/libs/gui/tests/Surface_test.cpp
index 4f87824..cf0043d 100644
--- a/libs/gui/tests/Surface_test.cpp
+++ b/libs/gui/tests/Surface_test.cpp
@@ -177,4 +177,37 @@ TEST_F(SurfaceTest, QueryDefaultBuffersDataSpace) {
     ASSERT_EQ(TEST_DATASPACE, dataSpace);
 }
 
+TEST_F(SurfaceTest, SettingGenerationNumber) {
+    sp<IGraphicBufferProducer> producer;
+    sp<IGraphicBufferConsumer> consumer;
+    BufferQueue::createBufferQueue(&producer, &consumer);
+    sp<CpuConsumer> cpuConsumer = new CpuConsumer(consumer, 1);
+    sp<Surface> surface = new Surface(producer);
+    sp<ANativeWindow> window(surface);
+
+    // Allocate a buffer with a generation number of 0
+    ANativeWindowBuffer* buffer;
+    int fenceFd;
+    ASSERT_EQ(NO_ERROR, window->dequeueBuffer(window.get(), &buffer, &fenceFd));
+    ASSERT_EQ(NO_ERROR, window->cancelBuffer(window.get(), buffer, fenceFd));
+
+    // Detach the buffer and check its generation number
+    sp<GraphicBuffer> graphicBuffer;
+    sp<Fence> fence;
+    ASSERT_EQ(NO_ERROR, surface->detachNextBuffer(&graphicBuffer, &fence));
+    ASSERT_EQ(0U, graphicBuffer->getGenerationNumber());
+
+    ASSERT_EQ(NO_ERROR, surface->setGenerationNumber(1));
+    buffer = static_cast<ANativeWindowBuffer*>(graphicBuffer.get());
+
+    // This should change the generation number of the GraphicBuffer
+    ASSERT_EQ(NO_ERROR, surface->attachBuffer(buffer));
+
+    // Check that the new generation number sticks with the buffer
+    ASSERT_EQ(NO_ERROR, window->cancelBuffer(window.get(), buffer, -1));
+    ASSERT_EQ(NO_ERROR, window->dequeueBuffer(window.get(), &buffer, &fenceFd));
+    graphicBuffer = static_cast<GraphicBuffer*>(buffer);
+    ASSERT_EQ(1U, graphicBuffer->getGenerationNumber());
+}
+
 }
diff --git a/libs/ui/GraphicBuffer.cpp b/libs/ui/GraphicBuffer.cpp
index 6a42a22..e55db30 100644
--- a/libs/ui/GraphicBuffer.cpp
+++ b/libs/ui/GraphicBuffer.cpp
@@ -278,7 +278,7 @@ status_t GraphicBuffer::unlockAsync(int *fenceFd)
 }
 
 size_t GraphicBuffer::getFlattenedSize() const {
-    return static_cast<size_t>(10 + (handle ? handle->numInts : 0)) * sizeof(int);
+    return static_cast<size_t>(11 + (handle ? handle->numInts : 0)) * sizeof(int);
 }
 
 size_t GraphicBuffer::getFdCount() const {
@@ -301,15 +301,16 @@ status_t GraphicBuffer::flatten(void*& buffer, size_t& size, int*& fds, size_t&
     buf[5] = usage;
     buf[6] = static_cast<int32_t>(mId >> 32);
     buf[7] = static_cast<int32_t>(mId & 0xFFFFFFFFull);
-    buf[8] = 0;
+    buf[8] = static_cast<int32_t>(mGenerationNumber);
     buf[9] = 0;
+    buf[10] = 0;
 
     if (handle) {
-        buf[8] = handle->numFds;
-        buf[9] = handle->numInts;
+        buf[9] = handle->numFds;
+        buf[10] = handle->numInts;
         memcpy(fds, handle->data,
                 static_cast<size_t>(handle->numFds) * sizeof(int));
-        memcpy(&buf[10], handle->data + handle->numFds,
+        memcpy(&buf[11], handle->data + handle->numFds,
                 static_cast<size_t>(handle->numInts) * sizeof(int));
     }
 
@@ -325,20 +326,20 @@ status_t GraphicBuffer::flatten(void*& buffer, size_t& size, int*& fds, size_t&
 
 status_t GraphicBuffer::unflatten(
         void const*& buffer, size_t& size, int const*& fds, size_t& count) {
-    if (size < 8*sizeof(int)) return NO_MEMORY;
+    if (size < 11 * sizeof(int)) return NO_MEMORY;
 
     int const* buf = static_cast<int const*>(buffer);
     if (buf[0] != 'GBFR') return BAD_TYPE;
 
-    const size_t numFds  = static_cast<size_t>(buf[8]);
-    const size_t numInts = static_cast<size_t>(buf[9]);
+    const size_t numFds  = static_cast<size_t>(buf[9]);
+    const size_t numInts = static_cast<size_t>(buf[10]);
 
     // Limit the maxNumber to be relatively small. The number of fds or ints
     // should not come close to this number, and the number itself was simply
     // chosen to be high enough to not cause issues and low enough to prevent
     // overflow problems.
     const size_t maxNumber = 4096;
-    if (numFds >= maxNumber || numInts >= (maxNumber - 10)) {
+    if (numFds >= maxNumber || numInts >= (maxNumber - 11)) {
         width = height = stride = format = usage = 0;
         handle = NULL;
         ALOGE("unflatten: numFds or numInts is too large: %zd, %zd",
@@ -346,7 +347,7 @@ status_t GraphicBuffer::unflatten(
         return BAD_VALUE;
     }
 
-    const size_t sizeNeeded = (10 + numInts) * sizeof(int);
+    const size_t sizeNeeded = (11 + numInts) * sizeof(int);
     if (size < sizeNeeded) return NO_MEMORY;
 
     size_t fdCountNeeded = numFds;
@@ -372,7 +373,7 @@ status_t GraphicBuffer::unflatten(
             return NO_MEMORY;
         }
         memcpy(h->data, fds, numFds * sizeof(int));
-        memcpy(h->data + numFds, &buf[10], numInts * sizeof(int));
+        memcpy(h->data + numFds, &buf[11], numInts * sizeof(int));
         handle = h;
     } else {
         width = height = stride = format = usage = 0;
@@ -382,6 +383,8 @@ status_t GraphicBuffer::unflatten(
     mId = static_cast<uint64_t>(buf[6]) << 32;
     mId |= static_cast<uint32_t>(buf[7]);
 
+    mGenerationNumber = static_cast<uint32_t>(buf[8]);
+
     mOwner = ownHandle;
 
     if (handle != 0) {
diff --git a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp
index 11cbdc6..ee8d41c 100644
--- a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp
+++ b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.cpp
@@ -530,6 +530,11 @@ status_t VirtualDisplaySurface::allowAllocation(bool /* allow */) {
     return INVALID_OPERATION;
 }
 
+status_t VirtualDisplaySurface::setGenerationNumber(uint32_t /* generation */) {
+    ALOGE("setGenerationNumber not supported on VirtualDisplaySurface");
+    return INVALID_OPERATION;
+}
+
 void VirtualDisplaySurface::updateQueueBufferOutput(
         const QueueBufferOutput& qbo) {
     uint32_t w, h, transformHint, numPendingBuffers;
diff --git a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
index 97af980..ff02290 100644
--- a/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
+++ b/services/surfaceflinger/DisplayHardware/VirtualDisplaySurface.h
@@ -116,6 +116,7 @@ private:
     virtual void allocateBuffers(bool async, uint32_t width, uint32_t height,
             PixelFormat format, uint32_t usage);
     virtual status_t allowAllocation(bool allow);
+    virtual status_t setGenerationNumber(uint32_t generationNumber);
 
     //
     // Utility methods
diff --git a/services/surfaceflinger/MonitoredProducer.cpp b/services/surfaceflinger/MonitoredProducer.cpp
index 9fb555b..6f25bf5 100644
--- a/services/surfaceflinger/MonitoredProducer.cpp
+++ b/services/surfaceflinger/MonitoredProducer.cpp
@@ -114,6 +114,10 @@ status_t MonitoredProducer::allowAllocation(bool allow) {
     return mProducer->allowAllocation(allow);
 }
 
+status_t MonitoredProducer::setGenerationNumber(uint32_t generationNumber) {
+    return mProducer->setGenerationNumber(generationNumber);
+}
+
 IBinder* MonitoredProducer::onAsBinder() {
     return IInterface::asBinder(mProducer).get();
 }
diff --git a/services/surfaceflinger/MonitoredProducer.h b/services/surfaceflinger/MonitoredProducer.h
index b2f8293..ff691d8 100644
--- a/services/surfaceflinger/MonitoredProducer.h
+++ b/services/surfaceflinger/MonitoredProducer.h
@@ -54,6 +54,7 @@ public:
     virtual void allocateBuffers(bool async, uint32_t width, uint32_t height,
             PixelFormat format, uint32_t usage);
     virtual status_t allowAllocation(bool allow);
+    virtual status_t setGenerationNumber(uint32_t generationNumber);
     virtual IBinder* onAsBinder();
 
 private: