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SyncRtSurfaceTransactionApplier: Improve thread safety

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If the calling thread releases the SurfaceControl passed
to SyncRtSurfaceTransactionApplier concurrently with the
applier preparing the transaction, this can lead to a
synchronization error and a crash. Once the state is
inside the transaction no further synchronization is required
as the native transaction will hold its own sp<SurfaceControl>
reference. By constructing the Transaction on the calling thread
and deferring application to the RenderThread we enable the calling
thread to not have any release synchronization requirements with
RenderThread.

Bug: 186391509
Change-Id: I585e1a9d3baf9ea384b00408b6253f34487d5037
This commit is contained in:
Robert Carr
2021-05-05 17:36:47 -07:00
committed by Rob Carr
parent 0e4d7f142b
commit e9ea91f47d
2 changed files with 13 additions and 8 deletions
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17
core/java/android/view/SyncRtSurfaceTransactionApplier.java
View File

@@ -54,20 +54,21 @@ public class SyncRtSurfaceTransactionApplier {
/**
* Schedules applying surface parameters on the next frame.
*
* @param params The surface parameters to apply. DO NOT MODIFY the list after passing into
* this method to avoid synchronization issues.
* @param params The surface parameters to apply.
*/
public void scheduleApply(final SurfaceParams... params) {
if (mTargetViewRootImpl == null) {
return;
}
mTargetSc = mTargetViewRootImpl.getSurfaceControl();
final Transaction t = new Transaction();
applyParams(t, params);
mTargetViewRootImpl.registerRtFrameCallback(frame -> {
if (mTargetSc == null || !mTargetSc.isValid()) {
return;
}
Transaction t = new Transaction();
applyParams(t, frame, params);
applyTransaction(t, frame);
});
// Make sure a frame gets scheduled.
@@ -78,15 +79,17 @@ public class SyncRtSurfaceTransactionApplier {
* Applies surface parameters on the next frame.
* @param t transaction to apply all parameters in.
* @param frame frame to synchronize to. Set -1 when sync is not required.
* @param params The surface parameters to apply. DO NOT MODIFY the list after passing into
* this method to avoid synchronization issues.
* @param params The surface parameters to apply.
*/
void applyParams(Transaction t, long frame, final SurfaceParams... params) {
void applyParams(Transaction t, final SurfaceParams... params) {
for (int i = params.length - 1; i >= 0; i--) {
SurfaceParams surfaceParams = params[i];
SurfaceControl surface = surfaceParams.surface;
applyParams(t, surfaceParams, mTmpFloat9);
}
}
void applyTransaction(Transaction t, long frame) {
if (mTargetViewRootImpl != null) {
mTargetViewRootImpl.mergeWithNextTransaction(t, frame);
} else {

4
core/java/android/view/ViewRootInsetsControllerHost.java
View File

@@ -127,7 +127,9 @@ public class ViewRootInsetsControllerHost implements InsetsController.Host {
// Window doesn't support hardware acceleration, no synchronization for now.
// TODO(b/149342281): use mViewRoot.mSurface.getNextFrameNumber() to sync on every
// frame instead.
mApplier.applyParams(new SurfaceControl.Transaction(), -1 /* frame */, params);
final SurfaceControl.Transaction t = new SurfaceControl.Transaction();
mApplier.applyParams(t, params);
mApplier.applyTransaction(t, -1);
}
}