Files
lawnchair/systemUIViewCapture/src/com/android/app/viewcapture/ViewCapture.java
2023-12-13 18:47:55 +08:00

624 lines
24 KiB
Java

/*
* Copyright (C) 2022 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.app.viewcapture;
import static com.android.app.viewcapture.data.ExportedData.MagicNumber.MAGIC_NUMBER_H;
import static com.android.app.viewcapture.data.ExportedData.MagicNumber.MAGIC_NUMBER_L;
import android.content.Context;
import android.content.res.Resources;
import android.media.permission.SafeCloseable;
import android.os.HandlerThread;
import android.os.Looper;
import android.os.SystemClock;
import android.os.Trace;
import android.text.TextUtils;
import android.util.SparseArray;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.view.Window;
import androidx.annotation.AnyThread;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.UiThread;
import androidx.annotation.VisibleForTesting;
import androidx.annotation.WorkerThread;
import com.android.app.viewcapture.data.ExportedData;
import com.android.app.viewcapture.data.FrameData;
import com.android.app.viewcapture.data.MotionWindowData;
import com.android.app.viewcapture.data.ViewNode;
import com.android.app.viewcapture.data.WindowData;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;
import java.util.function.Consumer;
import java.util.function.Predicate;
/**
* Utility class for capturing view data every frame
*/
public abstract class ViewCapture {
private static final String TAG = "ViewCapture";
// These flags are copies of two private flags in the View class.
private static final int PFLAG_INVALIDATED = 0x80000000;
private static final int PFLAG_DIRTY_MASK = 0x00200000;
private static final long MAGIC_NUMBER_FOR_WINSCOPE =
((long) MAGIC_NUMBER_H.getNumber() << 32) | MAGIC_NUMBER_L.getNumber();
// Number of frames to keep in memory
private final int mMemorySize;
protected static final int DEFAULT_MEMORY_SIZE = 2000;
// Initial size of the reference pool. This is at least be 5 * total number of views in
// Launcher. This allows the first free frames avoid object allocation during view capture.
protected static final int DEFAULT_INIT_POOL_SIZE = 300;
public static final LooperExecutor MAIN_EXECUTOR = new LooperExecutor(Looper.getMainLooper());
private final List<WindowListener> mListeners = new ArrayList<>();
protected final Executor mBgExecutor;
// Pool used for capturing view tree on the UI thread.
private ViewRef mPool = new ViewRef();
private boolean mIsEnabled = true;
protected ViewCapture(int memorySize, int initPoolSize, Executor bgExecutor) {
mMemorySize = memorySize;
mBgExecutor = bgExecutor;
mBgExecutor.execute(() -> initPool(initPoolSize));
}
public static LooperExecutor createAndStartNewLooperExecutor(String name, int priority) {
HandlerThread thread = new HandlerThread(name, priority);
thread.start();
return new LooperExecutor(thread.getLooper());
}
@UiThread
private void addToPool(ViewRef start, ViewRef end) {
end.next = mPool;
mPool = start;
}
@WorkerThread
private void initPool(int initPoolSize) {
ViewRef start = new ViewRef();
ViewRef current = start;
for (int i = 0; i < initPoolSize; i++) {
current.next = new ViewRef();
current = current.next;
}
ViewRef finalCurrent = current;
MAIN_EXECUTOR.execute(() -> addToPool(start, finalCurrent));
}
/**
* Attaches the ViewCapture to the provided window and returns a handle to detach the listener
*/
@NonNull
public SafeCloseable startCapture(Window window) {
String title = window.getAttributes().getTitle().toString();
String name = TextUtils.isEmpty(title) ? window.toString() : title;
return startCapture(window.getDecorView(), name);
}
/**
* Attaches the ViewCapture to the provided window and returns a handle to detach the listener.
* Verifies that ViewCapture is enabled before actually attaching an onDrawListener.
*/
@NonNull
public SafeCloseable startCapture(View view, String name) {
WindowListener listener = new WindowListener(view, name);
if (mIsEnabled) MAIN_EXECUTOR.execute(listener::attachToRoot);
mListeners.add(listener);
return () -> {
mListeners.remove(listener);
listener.detachFromRoot();
};
}
/**
* Launcher checks for leaks in many spots during its instrumented tests. The WindowListeners
* appear to have leaks because they store mRoot views. In reality, attached views close their
* respective window listeners when they are destroyed.
* <p>
* This method deletes detaches and deletes mRoot views from windowListeners. This makes the
* WindowListeners unusable for anything except dumping previously captured information. They
* are still technically enabled to allow for dumping.
*/
@VisibleForTesting
public void stopCapture(@NonNull View rootView) {
mListeners.forEach(it -> {
if (rootView == it.mRoot) {
it.mRoot.getViewTreeObserver().removeOnDrawListener(it);
it.mRoot = null;
}
});
}
@UiThread
protected void enableOrDisableWindowListeners(boolean isEnabled) {
mIsEnabled = isEnabled;
mListeners.forEach(WindowListener::detachFromRoot);
if (mIsEnabled) mListeners.forEach(WindowListener::attachToRoot);
}
@AnyThread
public void dumpTo(OutputStream os, Context context)
throws InterruptedException, ExecutionException, IOException {
if (mIsEnabled) getExportedData(context).writeTo(os);
}
@VisibleForTesting
public ExportedData getExportedData(Context context)
throws InterruptedException, ExecutionException {
ArrayList<Class> classList = new ArrayList<>();
return ExportedData.newBuilder()
.setMagicNumber(MAGIC_NUMBER_FOR_WINSCOPE)
.setPackage(context.getPackageName())
.addAllWindowData(getWindowData(context, classList, l -> l.mIsActive).get())
.addAllClassname(toStringList(classList))
.setRealToElapsedTimeOffsetNanos(TimeUnit.MILLISECONDS
.toNanos(System.currentTimeMillis()) - SystemClock.elapsedRealtimeNanos())
.build();
}
private static List<String> toStringList(List<Class> classList) {
return classList.stream().map(Class::getName).toList();
}
public CompletableFuture<Optional<MotionWindowData>> getDumpTask(View view) {
ArrayList<Class> classList = new ArrayList<>();
return getWindowData(view.getContext().getApplicationContext(), classList,
l -> l.mRoot.equals(view)).thenApply(list -> list.stream().findFirst().map(w ->
MotionWindowData.newBuilder()
.addAllFrameData(w.getFrameDataList())
.addAllClassname(toStringList(classList))
.build()));
}
@AnyThread
private CompletableFuture<List<WindowData>> getWindowData(Context context,
ArrayList<Class> outClassList, Predicate<WindowListener> filter) {
ViewIdProvider idProvider = new ViewIdProvider(context.getResources());
return CompletableFuture.supplyAsync(() ->
mListeners.stream().filter(filter).toList(), MAIN_EXECUTOR).thenApplyAsync(it ->
it.stream().map(l -> l.dumpToProto(idProvider, outClassList)).toList(),
mBgExecutor);
}
/**
* Once this window listener is attached to a window's root view, it traverses the entire
* view tree on the main thread every time onDraw is called. It then saves the state of the view
* tree traversed in a local list of nodes, so that this list of nodes can be processed on a
* background thread, and prepared for being dumped into a bugreport.
*
* Since some of the work needs to be done on the main thread after every draw, this piece of
* code needs to be hyper optimized. That is why we are recycling ViewRef and ViewPropertyRef
* objects and storing the list of nodes as a flat LinkedList, rather than as a tree. This data
* structure allows recycling to happen in O(1) time via pointer assignment. Without this
* optimization, a lot of time is wasted creating ViewRef objects, or finding ViewRef objects to
* recycle.
*
* Another optimization is to only traverse view nodes on the main thread that have potentially
* changed since the last frame was drawn. This can be determined via a combination of private
* flags inside the View class.
*
* Another optimization is to not store or manipulate any string objects on the main thread.
* While this might seem trivial, using Strings in any form causes the ViewCapture to hog the
* main thread for up to an additional 6-7ms. It must be avoided at all costs.
*
* Another optimization is to only store the class names of the Views in the view hierarchy one
* time. They are then referenced via a classNameIndex value stored in each ViewPropertyRef.
*
* TODO: b/262585897: If further memory optimization is required, an effective one would be to
* only store the changes between frames, rather than the entire node tree for each frame.
* The go/web-hv UX already does this, and has reaped significant memory improves because of it.
*
* TODO: b/262585897: Another memory optimization could be to store all integer, float, and
* boolean information via single integer values via the Chinese remainder theorem, or a similar
* algorithm, which enables multiple numerical values to be stored inside 1 number. Doing this
* would allow each ViewProperty / ViewRef to slim down its memory footprint significantly.
*
* One important thing to remember is that bugs related to recycling will usually only appear
* after at least 2000 frames have been rendered. If that code is changed, the tester can
* use hard-coded logs to verify that recycling is happening, and test view capturing at least
* ~8000 frames or so to verify the recycling functionality is working properly.
*/
private class WindowListener implements ViewTreeObserver.OnDrawListener {
@Nullable // Nullable in tests only
public View mRoot;
public final String name;
private final ViewRef mViewRef = new ViewRef();
private int mFrameIndexBg = -1;
private boolean mIsFirstFrame = true;
private final long[] mFrameTimesNanosBg = new long[mMemorySize];
private final ViewPropertyRef[] mNodesBg = new ViewPropertyRef[mMemorySize];
private boolean mIsActive = true;
private final Consumer<ViewRef> mCaptureCallback = this::captureViewPropertiesBg;
WindowListener(View view, String name) {
mRoot = view;
this.name = name;
}
/**
* Every time onDraw is called, it does the minimal set of work required on the main thread,
* i.e. capturing potentially dirty / invalidated views, and then immediately offloads the
* rest of the processing work (extracting the captured view properties) to a background
* thread via mExecutor.
*/
@Override
public void onDraw() {
Trace.beginSection("view_capture");
captureViewTree(mRoot, mViewRef);
ViewRef captured = mViewRef.next;
if (captured != null) {
captured.callback = mCaptureCallback;
captured.elapsedRealtimeNanos = SystemClock.elapsedRealtimeNanos();
mBgExecutor.execute(captured);
}
mIsFirstFrame = false;
Trace.endSection();
}
/**
* Captures the View property on the background thread, and transfer all the ViewRef objects
* back to the pool
*/
@WorkerThread
private void captureViewPropertiesBg(ViewRef viewRefStart) {
long elapsedRealtimeNanos = viewRefStart.elapsedRealtimeNanos;
mFrameIndexBg++;
if (mFrameIndexBg >= mMemorySize) {
mFrameIndexBg = 0;
}
mFrameTimesNanosBg[mFrameIndexBg] = elapsedRealtimeNanos;
ViewPropertyRef recycle = mNodesBg[mFrameIndexBg];
ViewPropertyRef resultStart = null;
ViewPropertyRef resultEnd = null;
ViewRef viewRefEnd = viewRefStart;
while (viewRefEnd != null) {
ViewPropertyRef propertyRef = recycle;
if (propertyRef == null) {
propertyRef = new ViewPropertyRef();
} else {
recycle = recycle.next;
propertyRef.next = null;
}
ViewPropertyRef copy = null;
if (viewRefEnd.childCount < 0) {
copy = findInLastFrame(viewRefEnd.view.hashCode());
viewRefEnd.childCount = (copy != null) ? copy.childCount : 0;
}
viewRefEnd.transferTo(propertyRef);
if (resultStart == null) {
resultStart = propertyRef;
resultEnd = resultStart;
} else {
resultEnd.next = propertyRef;
resultEnd = resultEnd.next;
}
if (copy != null) {
int pending = copy.childCount;
while (pending > 0) {
copy = copy.next;
pending = pending - 1 + copy.childCount;
propertyRef = recycle;
if (propertyRef == null) {
propertyRef = new ViewPropertyRef();
} else {
recycle = recycle.next;
propertyRef.next = null;
}
copy.transferTo(propertyRef);
resultEnd.next = propertyRef;
resultEnd = resultEnd.next;
}
}
if (viewRefEnd.next == null) {
// The compiler will complain about using a non-final variable from
// an outer class in a lambda if we pass in viewRefEnd directly.
final ViewRef finalViewRefEnd = viewRefEnd;
MAIN_EXECUTOR.execute(() -> addToPool(viewRefStart, finalViewRefEnd));
break;
}
viewRefEnd = viewRefEnd.next;
}
mNodesBg[mFrameIndexBg] = resultStart;
}
private @Nullable ViewPropertyRef findInLastFrame(int hashCode) {
int lastFrameIndex = (mFrameIndexBg == 0) ? mMemorySize - 1 : mFrameIndexBg - 1;
ViewPropertyRef viewPropertyRef = mNodesBg[lastFrameIndex];
while (viewPropertyRef != null && viewPropertyRef.hashCode != hashCode) {
viewPropertyRef = viewPropertyRef.next;
}
return viewPropertyRef;
}
void attachToRoot() {
mIsActive = true;
if (mRoot.isAttachedToWindow()) {
safelyEnableOnDrawListener();
} else {
mRoot.addOnAttachStateChangeListener(new View.OnAttachStateChangeListener() {
@Override
public void onViewAttachedToWindow(View v) {
if (mIsActive) {
safelyEnableOnDrawListener();
}
mRoot.removeOnAttachStateChangeListener(this);
}
@Override
public void onViewDetachedFromWindow(View v) {
}
});
}
}
void detachFromRoot() {
mIsActive = false;
if (mRoot != null) {
mRoot.getViewTreeObserver().removeOnDrawListener(this);
}
}
private void safelyEnableOnDrawListener() {
mRoot.getViewTreeObserver().removeOnDrawListener(this);
mRoot.getViewTreeObserver().addOnDrawListener(this);
}
@WorkerThread
private WindowData dumpToProto(ViewIdProvider idProvider, ArrayList<Class> classList) {
WindowData.Builder builder = WindowData.newBuilder().setTitle(name);
int size = (mNodesBg[mMemorySize - 1] == null) ? mFrameIndexBg + 1 : mMemorySize;
for (int i = size - 1; i >= 0; i--) {
int index = (mMemorySize + mFrameIndexBg - i) % mMemorySize;
ViewNode.Builder nodeBuilder = ViewNode.newBuilder();
mNodesBg[index].toProto(idProvider, classList, nodeBuilder);
FrameData.Builder frameDataBuilder = FrameData.newBuilder()
.setNode(nodeBuilder)
.setTimestamp(mFrameTimesNanosBg[index]);
builder.addFrameData(frameDataBuilder);
}
return builder.build();
}
private ViewRef captureViewTree(View view, ViewRef start) {
ViewRef ref;
if (mPool != null) {
ref = mPool;
mPool = mPool.next;
ref.next = null;
} else {
ref = new ViewRef();
}
ref.view = view;
start.next = ref;
if (view instanceof ViewGroup) {
ViewGroup parent = (ViewGroup) view;
// If a view has not changed since the last frame, we will copy
// its children from the last processed frame's data.
if ((view.mPrivateFlags & (PFLAG_INVALIDATED | PFLAG_DIRTY_MASK)) == 0
&& !mIsFirstFrame) {
// A negative child count is the signal to copy this view from the last frame.
ref.childCount = -parent.getChildCount();
return ref;
}
ViewRef result = ref;
int childCount = ref.childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
result = captureViewTree(parent.getChildAt(i), result);
}
return result;
} else {
ref.childCount = 0;
return ref;
}
}
}
private static class ViewPropertyRef {
// We store reference in memory to avoid generating and storing too many strings
public Class clazz;
public int hashCode;
public int childCount = 0;
public int id;
public int left, top, right, bottom;
public int scrollX, scrollY;
public float translateX, translateY;
public float scaleX, scaleY;
public float alpha;
public float elevation;
public int visibility;
public boolean willNotDraw;
public boolean clipChildren;
public ViewPropertyRef next;
public void transferTo(ViewPropertyRef out) {
out.clazz = this.clazz;
out.hashCode = this.hashCode;
out.childCount = this.childCount;
out.id = this.id;
out.left = this.left;
out.top = this.top;
out.right = this.right;
out.bottom = this.bottom;
out.scrollX = this.scrollX;
out.scrollY = this.scrollY;
out.scaleX = this.scaleX;
out.scaleY = this.scaleY;
out.translateX = this.translateX;
out.translateY = this.translateY;
out.alpha = this.alpha;
out.visibility = this.visibility;
out.willNotDraw = this.willNotDraw;
out.clipChildren = this.clipChildren;
out.elevation = this.elevation;
}
/**
* Converts the data to the proto representation and returns the next property ref
* at the end of the iteration.
*/
public ViewPropertyRef toProto(ViewIdProvider idProvider, ArrayList<Class> classList,
ViewNode.Builder viewNode) {
int classnameIndex = classList.indexOf(clazz);
if (classnameIndex < 0) {
classnameIndex = classList.size();
classList.add(clazz);
}
viewNode.setClassnameIndex(classnameIndex)
.setHashcode(hashCode)
.setId(idProvider.getName(id))
.setLeft(left)
.setTop(top)
.setWidth(right - left)
.setHeight(bottom - top)
.setTranslationX(translateX)
.setTranslationY(translateY)
.setScrollX(scrollX)
.setScrollY(scrollY)
.setScaleX(scaleX)
.setScaleY(scaleY)
.setAlpha(alpha)
.setVisibility(visibility)
.setWillNotDraw(willNotDraw)
.setElevation(elevation)
.setClipChildren(clipChildren);
ViewPropertyRef result = next;
for (int i = 0; (i < childCount) && (result != null); i++) {
ViewNode.Builder childViewNode = ViewNode.newBuilder();
result = result.toProto(idProvider, classList, childViewNode);
viewNode.addChildren(childViewNode);
}
return result;
}
}
private static class ViewRef implements Runnable {
public View view;
public int childCount = 0;
public ViewRef next;
public Consumer<ViewRef> callback = null;
public long elapsedRealtimeNanos = 0;
public void transferTo(ViewPropertyRef out) {
out.childCount = this.childCount;
View view = this.view;
this.view = null;
out.clazz = view.getClass();
out.hashCode = view.hashCode();
out.id = view.getId();
out.left = view.getLeft();
out.top = view.getTop();
out.right = view.getRight();
out.bottom = view.getBottom();
out.scrollX = view.getScrollX();
out.scrollY = view.getScrollY();
out.translateX = view.getTranslationX();
out.translateY = view.getTranslationY();
out.scaleX = view.getScaleX();
out.scaleY = view.getScaleY();
out.alpha = view.getAlpha();
out.elevation = view.getElevation();
out.visibility = view.getVisibility();
out.willNotDraw = view.willNotDraw();
}
@Override
public void run() {
Consumer<ViewRef> oldCallback = callback;
callback = null;
if (oldCallback != null) {
oldCallback.accept(this);
}
}
}
private static final class ViewIdProvider {
private final SparseArray<String> mNames = new SparseArray<>();
private final Resources mRes;
ViewIdProvider(Resources res) {
mRes = res;
}
String getName(int id) {
String name = mNames.get(id);
if (name == null) {
if (id >= 0) {
try {
name = mRes.getResourceTypeName(id) + '/' + mRes.getResourceEntryName(id);
} catch (Resources.NotFoundException e) {
name = "id/" + "0x" + Integer.toHexString(id).toUpperCase();
}
} else {
name = "NO_ID";
}
mNames.put(id, name);
}
return name;
}
}
}