Create test for screenshots with null snapshots

Snapshots can be null when a layer is offscreen and unparented.
The best way to simulate this in a test is to mirror an offscreen
layer and check if the screenshot path works. Also adds more
informative screenshot deubg logs.

Bug: b/331874495, b/331923495
Test: atest ScreenCapturetest
Change-Id: I4fcd822f00e6427ebaf899756f95e6790b035544

3 files changed, 42 insertions, 8 deletions

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 949a030c1f..81697da5e1 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -7838,17 +7838,19 @@ void SurfaceFlinger::captureDisplay(const DisplayCaptureArgs& args,
 
     status_t validate = validateScreenshotPermissions(args);
     if (validate != OK) {
+        ALOGD("Permission denied to captureDisplay");
         invokeScreenCaptureError(validate, captureListener);
         return;
     }
 
     if (!args.displayToken) {
+        ALOGD("Invalid display token to captureDisplay");
         invokeScreenCaptureError(BAD_VALUE, captureListener);
         return;
     }
 
     if (args.captureSecureLayers && !hasCaptureBlackoutContentPermission()) {
-        ALOGE("Attempting to capture secure layers without CAPTURE_BLACKOUT_CONTENT");
+        ALOGD("Attempting to capture secure layers without CAPTURE_BLACKOUT_CONTENT");
         invokeScreenCaptureError(PERMISSION_DENIED, captureListener);
         return;
     }
@@ -7861,6 +7863,7 @@ void SurfaceFlinger::captureDisplay(const DisplayCaptureArgs& args,
         Mutex::Autolock lock(mStateLock);
         sp<DisplayDevice> display = getDisplayDeviceLocked(args.displayToken);
         if (!display) {
+            ALOGD("Unable to find display device for captureDisplay");
             invokeScreenCaptureError(NAME_NOT_FOUND, captureListener);
             return;
         }
@@ -7877,7 +7880,7 @@ void SurfaceFlinger::captureDisplay(const DisplayCaptureArgs& args,
             if (excludeLayer != UNASSIGNED_LAYER_ID) {
                 excludeLayerIds.emplace(excludeLayer);
             } else {
-                ALOGW("Invalid layer handle passed as excludeLayer to captureDisplay");
+                ALOGD("Invalid layer handle passed as excludeLayer to captureDisplay");
                 invokeScreenCaptureError(NAME_NOT_FOUND, captureListener);
                 return;
             }
@@ -7915,6 +7918,7 @@ void SurfaceFlinger::captureDisplay(DisplayId displayId, const CaptureArgs& args
 
         const auto display = getDisplayDeviceLocked(displayId);
         if (!display) {
+            ALOGD("Unable to find display device for captureDisplay");
             invokeScreenCaptureError(NAME_NOT_FOUND, captureListener);
             return;
         }
@@ -7932,7 +7936,7 @@ void SurfaceFlinger::captureDisplay(DisplayId displayId, const CaptureArgs& args
     constexpr auto kMaxTextureSize = 16384;
     if (size.width <= 0 || size.height <= 0 || size.width >= kMaxTextureSize ||
         size.height >= kMaxTextureSize) {
-        ALOGE("capture display resolved to invalid size %d x %d", size.width, size.height);
+        ALOGD("captureDisplay resolved to invalid size %d x %d", size.width, size.height);
         invokeScreenCaptureError(BAD_VALUE, captureListener);
         return;
     }
@@ -7979,6 +7983,7 @@ void SurfaceFlinger::captureLayers(const LayerCaptureArgs& args,
 
     status_t validate = validateScreenshotPermissions(args);
     if (validate != OK) {
+        ALOGD("Permission denied to captureLayers");
         invokeScreenCaptureError(validate, captureListener);
         return;
     }
@@ -7990,7 +7995,7 @@ void SurfaceFlinger::captureLayers(const LayerCaptureArgs& args,
     ui::Dataspace dataspace = args.dataspace;
 
     if (args.captureSecureLayers && !hasCaptureBlackoutContentPermission()) {
-        ALOGE("Attempting to capture secure layers without CAPTURE_BLACKOUT_CONTENT");
+        ALOGD("Attempting to capture secure layers without CAPTURE_BLACKOUT_CONTENT");
         invokeScreenCaptureError(PERMISSION_DENIED, captureListener);
         return;
     }
@@ -8000,7 +8005,7 @@ void SurfaceFlinger::captureLayers(const LayerCaptureArgs& args,
 
         parent = LayerHandle::getLayer(args.layerHandle);
         if (parent == nullptr) {
-            ALOGE("captureLayers called with an invalid or removed parent");
+            ALOGD("captureLayers called with an invalid or removed parent");
             invokeScreenCaptureError(NAME_NOT_FOUND, captureListener);
             return;
         }
@@ -8019,6 +8024,7 @@ void SurfaceFlinger::captureLayers(const LayerCaptureArgs& args,
         if (crop.isEmpty() || args.frameScaleX <= 0.0f || args.frameScaleY <= 0.0f) {
             // Error out if the layer has no source bounds (i.e. they are boundless) and a source
             // crop was not specified, or an invalid frame scale was provided.
+            ALOGD("Boundless layer, unspecified crop, or invalid frame scale to captureLayers");
             invokeScreenCaptureError(BAD_VALUE, captureListener);
             return;
         }
@@ -8029,7 +8035,7 @@ void SurfaceFlinger::captureLayers(const LayerCaptureArgs& args,
             if (excludeLayer != UNASSIGNED_LAYER_ID) {
                 excludeLayerIds.emplace(excludeLayer);
             } else {
-                ALOGW("Invalid layer handle passed as excludeLayer to captureLayers");
+                ALOGD("Invalid layer handle passed as excludeLayer to captureLayers");
                 invokeScreenCaptureError(NAME_NOT_FOUND, captureListener);
                 return;
             }
@@ -8038,7 +8044,7 @@ void SurfaceFlinger::captureLayers(const LayerCaptureArgs& args,
 
     // really small crop or frameScale
     if (reqSize.width <= 0 || reqSize.height <= 0) {
-        ALOGW("Failed to captureLayers: crop or scale too small");
+        ALOGD("Failed to captureLayers: crop or scale too small");
         invokeScreenCaptureError(BAD_VALUE, captureListener);
         return;
     }
@@ -8103,7 +8109,7 @@ void SurfaceFlinger::captureLayers(const LayerCaptureArgs& args,
     }
 
     if (captureListener == nullptr) {
-        ALOGE("capture screen must provide a capture listener callback");
+        ALOGD("capture screen must provide a capture listener callback");
         invokeScreenCaptureError(BAD_VALUE, captureListener);
         return;
     }
@@ -9869,6 +9875,7 @@ binder::Status SurfaceComposerAIDL::captureDisplayById(
         std::optional<DisplayId> id = DisplayId::fromValue(static_cast<uint64_t>(displayId));
         mFlinger->captureDisplay(*id, args, captureListener);
     } else {
+        ALOGD("Permission denied to captureDisplayById");
         invokeScreenCaptureError(PERMISSION_DENIED, captureListener);
     }
     return binderStatusFromStatusT(NO_ERROR);
diff --git a/services/surfaceflinger/tests/LayerTransactionTest.h b/services/surfaceflinger/tests/LayerTransactionTest.h
index c9af432513..5b056d0765 100644
--- a/services/surfaceflinger/tests/LayerTransactionTest.h
+++ b/services/surfaceflinger/tests/LayerTransactionTest.h
@@ -106,6 +106,10 @@ protected:
         return colorLayer;
     }
 
+    sp<SurfaceControl> mirrorSurface(SurfaceControl* mirrorFromSurface) {
+        return mClient->mirrorSurface(mirrorFromSurface);
+    }
+
     ANativeWindow_Buffer getBufferQueueLayerBuffer(const sp<SurfaceControl>& layer) {
         // wait for previous transactions (such as setSize) to complete
         Transaction().apply(true);
diff --git a/services/surfaceflinger/tests/ScreenCapture_test.cpp b/services/surfaceflinger/tests/ScreenCapture_test.cpp
index 18262f664a..9a78550d00 100644
--- a/services/surfaceflinger/tests/ScreenCapture_test.cpp
+++ b/services/surfaceflinger/tests/ScreenCapture_test.cpp
@@ -1039,6 +1039,29 @@ TEST_F(ScreenCaptureTest, CaptureHdrLayer) {
     ASSERT_TRUE(mCapture->capturedHdrLayers());
 }
 
+TEST_F(ScreenCaptureTest, captureOffscreenNullSnapshot) {
+    sp<SurfaceControl> layer;
+    ASSERT_NO_FATAL_FAILURE(layer = createLayer("test layer", 32, 32,
+                                                ISurfaceComposerClient::eFXSurfaceBufferState,
+                                                mBGSurfaceControl.get()));
+
+    // A mirrored layer will not have a snapshot. Testing an offscreen mirrored layer
+    // ensures that the screenshot path handles cases where snapshots are null.
+    sp<SurfaceControl> mirroredLayer;
+    ASSERT_NO_FATAL_FAILURE(mirroredLayer = mirrorSurface(layer.get()));
+
+    LayerCaptureArgs captureArgs;
+    captureArgs.layerHandle = mirroredLayer->getHandle();
+    captureArgs.sourceCrop = Rect(0, 0, 1, 1);
+
+    // Screenshot path should only use the children of the layer hierarchy so
+    // that it will not create a new snapshot. A snapshot would otherwise be
+    // created to pass on the properties of the parent, which is not needed
+    // for the purposes of this test since we explicitly want a null snapshot.
+    captureArgs.childrenOnly = true;
+    ScreenCapture::captureLayers(&mCapture, captureArgs);
+}
+
 // In the following tests we verify successful skipping of a parent layer,
 // so we use the same verification logic and only change how we mutate
 // the parent layer to verify that various properties are ignored.