From 4efd0d936e2a2bfd9a46432270d7960062265c7b Mon Sep 17 00:00:00 2001
From: Anton Ivanov <aii@google.com>
Date: Fri, 14 Feb 2025 17:08:55 -0800
Subject: Delay initialization of a ConsumerBase instance to construction of a
 sp/wp.

This is needed to ensure correcntess of wp view of `this` which is
needed during initialization.

Bug: 393217449
Test: presubmit
Flag: EXEMPT_refactor
Change-Id: I1c4ec5d4487e9bb7f16a2654e38b27d32d2b82f3
---
 libs/gui/ConsumerBase.cpp | 32 ++++++++++++++++++--------------
 1 file changed, 18 insertions(+), 14 deletions(-)

(limited to 'libs/gui/ConsumerBase.cpp')

diff --git a/libs/gui/ConsumerBase.cpp b/libs/gui/ConsumerBase.cpp
index 0266a3f2e0..117a362661 100644
--- a/libs/gui/ConsumerBase.cpp
+++ b/libs/gui/ConsumerBase.cpp
@@ -31,6 +31,7 @@
 #include <gui/BufferItem.h>
 #include <gui/BufferQueue.h>
 #include <gui/ConsumerBase.h>
+#include <gui/IConsumerListener.h>
 #include <gui/ISurfaceComposer.h>
 #include <gui/Surface.h>
 #include <gui/SurfaceComposerClient.h>
@@ -68,8 +69,8 @@ ConsumerBase::ConsumerBase(const sp<IGraphicBufferConsumer>& bufferQueue, bool c
 #endif
         mAbandoned(false),
         mConsumer(bufferQueue),
-        mPrevFinalReleaseFence(Fence::NO_FENCE) {
-    initialize(controlledByApp);
+        mPrevFinalReleaseFence(Fence::NO_FENCE),
+        mIsControlledByApp(controlledByApp) {
 }
 
 #if COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(WB_CONSUMER_BASE_OWNS_BQ)
@@ -79,11 +80,11 @@ ConsumerBase::ConsumerBase(bool controlledByApp, bool consumerIsSurfaceFlinger)
         mSlots(BufferQueueDefs::NUM_BUFFER_SLOTS),
 #endif
         mAbandoned(false),
-        mPrevFinalReleaseFence(Fence::NO_FENCE) {
+        mPrevFinalReleaseFence(Fence::NO_FENCE),
+        mIsControlledByApp(controlledByApp) {
     sp<IGraphicBufferProducer> producer;
     BufferQueue::createBufferQueue(&producer, &mConsumer, consumerIsSurfaceFlinger);
     mSurface = sp<Surface>::make(producer, controlledByApp);
-    initialize(controlledByApp);
 }
 
 ConsumerBase::ConsumerBase(const sp<IGraphicBufferProducer>& producer,
@@ -95,24 +96,27 @@ ConsumerBase::ConsumerBase(const sp<IGraphicBufferProducer>& producer,
         mAbandoned(false),
         mConsumer(consumer),
         mSurface(sp<Surface>::make(producer, controlledByApp)),
-        mPrevFinalReleaseFence(Fence::NO_FENCE) {
-    initialize(controlledByApp);
+        mPrevFinalReleaseFence(Fence::NO_FENCE),
+        mIsControlledByApp(controlledByApp) {
 }
 
 #endif // COM_ANDROID_GRAPHICS_LIBGUI_FLAGS(WB_CONSUMER_BASE_OWNS_BQ)
 
-void ConsumerBase::initialize(bool controlledByApp) {
+void ConsumerBase::onFirstRef() {
+    ConsumerListener::onFirstRef();
+    initialize();
+}
+
+void ConsumerBase::initialize() {
     // Choose a name using the PID and a process-unique ID.
     mName = String8::format("unnamed-%d-%d", getpid(), createProcessUniqueId());
 
-    // Note that we can't create an sp<...>(this) in a ctor that will not keep a
-    // reference once the ctor ends, as that would cause the refcount of 'this'
-    // dropping to 0 at the end of the ctor.  Since all we need is a wp<...>
-    // that's what we create.
-    wp<ConsumerListener> listener = static_cast<ConsumerListener*>(this);
-    sp<IConsumerListener> proxy = new BufferQueue::ProxyConsumerListener(listener);
+    // Here we depend on an sp/wp having been created for `this`.  For this
+    // reason, initialize() cannot be called from a ctor.
+    wp<ConsumerListener> listener = wp<ConsumerListener>::fromExisting(this);
+    sp<IConsumerListener> proxy = sp<BufferQueue::ProxyConsumerListener>::make(listener);
 
-    status_t err = mConsumer->consumerConnect(proxy, controlledByApp);
+    status_t err = mConsumer->consumerConnect(proxy, mIsControlledByApp);
     if (err != NO_ERROR) {
         CB_LOGE("ConsumerBase: error connecting to BufferQueue: %s (%d)",
                 strerror(-err), err);
-- 
cgit v1.2.3-59-g8ed1b