Add the MIN_UNDEQUEUED_BUFFERS query to ANW.

This change adds a new query to ANativeWindow for getting the minimum
number of buffers that must be left un-dequeued during the steady-state
operation of the ANativeWindow.

Change-Id: Ie8c461fc26b02ecde02ddb4f95bf763662cf1551
Related-Bug: 3356050

3 files changed, 23 insertions, 2 deletions

diff --git a/libs/gui/SurfaceTexture.cpp b/libs/gui/SurfaceTexture.cpp
index 223cf09..3bed959 100644
--- a/libs/gui/SurfaceTexture.cpp
+++ b/libs/gui/SurfaceTexture.cpp
@@ -96,6 +96,11 @@ SurfaceTexture::~SurfaceTexture() {
 
 status_t SurfaceTexture::setBufferCount(int bufferCount) {
     LOGV("SurfaceTexture::setBufferCount");
+
+    if (bufferCount < MIN_BUFFER_SLOTS) {
+        return BAD_VALUE;
+    }
+
     Mutex::Autolock lock(mMutex);
     freeAllBuffers();
     mBufferCount = bufferCount;
diff --git a/libs/gui/SurfaceTextureClient.cpp b/libs/gui/SurfaceTextureClient.cpp
index ee14ac9..43b330c 100644
--- a/libs/gui/SurfaceTextureClient.cpp
+++ b/libs/gui/SurfaceTextureClient.cpp
@@ -143,8 +143,21 @@ int SurfaceTextureClient::queueBuffer(android_native_buffer_t* buffer) {
 int SurfaceTextureClient::query(int what, int* value) {
     LOGV("SurfaceTextureClient::query");
     Mutex::Autolock lock(mMutex);
-    // XXX: Implement this!
-    return INVALID_OPERATION;
+    switch (what) {
+    case NATIVE_WINDOW_WIDTH:
+    case NATIVE_WINDOW_HEIGHT:
+        // XXX: How should SurfaceTexture behave if setBuffersGeometry didn't
+        // override the size?
+        *value = 0;
+        return NO_ERROR;
+    case NATIVE_WINDOW_FORMAT:
+        *value = DEFAULT_FORMAT;
+        return NO_ERROR;
+    case NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS:
+        *value = MIN_UNDEQUEUED_BUFFERS;
+        return NO_ERROR;
+    }
+    return BAD_VALUE;
 }
 
 int SurfaceTextureClient::perform(int operation, va_list args)
diff --git a/libs/surfaceflinger_client/Surface.cpp b/libs/surfaceflinger_client/Surface.cpp
index 1e9bd74..2c77edf 100644
--- a/libs/surfaceflinger_client/Surface.cpp
+++ b/libs/surfaceflinger_client/Surface.cpp
@@ -709,6 +709,9 @@ int Surface::query(int what, int* value)
     case NATIVE_WINDOW_FORMAT:
         *value = int(mFormat);
         return NO_ERROR;
+    case NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS:
+        *value = MIN_UNDEQUEUED_BUFFERS;
+        return NO_ERROR;
     }
     return BAD_VALUE;
 }