Change slot generation for BufferState

BufferState layers now do slot generation with buffer death considered
appropriately.  When a buffer dies, the slot will be pushed onto a stack
of available slots to be reused at the next opportunity.  This should
mimic BufferQueue slot behavior and prevent Composer Resources from
growing too large.

Test: build, boot, manual
Bug: 129351223

Change-Id: Icef9592593cacb0b5c6b12f6679fc2c4dabdcd19

2 files changed, 10 insertions, 6 deletions

diff --git a/libs/gui/include/gui/ISurfaceComposer.h b/libs/gui/include/gui/ISurfaceComposer.h
index 415b2d58e..e8c7a39ad 100644
--- a/libs/gui/include/gui/ISurfaceComposer.h
+++ b/libs/gui/include/gui/ISurfaceComposer.h
@@ -44,7 +44,7 @@
 namespace android {
 // ----------------------------------------------------------------------------
 
-struct cached_buffer_t;
+struct client_cache_t;
 struct ComposerState;
 struct DisplayState;
 struct DisplayInfo;
@@ -137,7 +137,7 @@ public:
                                      const sp<IBinder>& applyToken,
                                      const InputWindowCommands& inputWindowCommands,
                                      int64_t desiredPresentTime,
-                                     const cached_buffer_t& uncacheBuffer,
+                                     const client_cache_t& uncacheBuffer,
                                      const std::vector<ListenerCallbacks>& listenerCallbacks) = 0;
 
     /* signal that we're done booting.
diff --git a/libs/gui/include/gui/LayerState.h b/libs/gui/include/gui/LayerState.h
index 225649775..f438eb3d0 100644
--- a/libs/gui/include/gui/LayerState.h
+++ b/libs/gui/include/gui/LayerState.h
@@ -40,9 +40,13 @@ namespace android {
 class Parcel;
 class ISurfaceComposerClient;
 
-struct cached_buffer_t {
-    sp<IBinder> token = nullptr;
-    uint64_t cacheId;
+struct client_cache_t {
+    wp<IBinder> token = nullptr;
+    uint64_t id;
+
+    bool operator==(const client_cache_t& other) const { return id == other.id; }
+
+    bool isValid() const { return token != nullptr; }
 };
 
 /*
@@ -187,7 +191,7 @@ struct layer_state_t {
     InputWindowInfo inputInfo;
 #endif
 
-    cached_buffer_t cachedBuffer;
+    client_cache_t cachedBuffer;
 
     LayerMetadata metadata;