Merge "Remove ViewTreeObserver allocations" (95fc7a24) · Commits · e / os / android_frameworks_base

core/java/android/view/ViewTreeObserver.java

+145 −34

Original line number	Diff line number	Diff line
		@@ -32,12 +32,18 @@ import java.util.concurrent.CopyOnWriteArrayList;
		* for more information.
		*/
		public final class ViewTreeObserver {
		// Recursive listeners use CopyOnWriteArrayList
		private CopyOnWriteArrayList<OnGlobalFocusChangeListener> mOnGlobalFocusListeners;
		private CopyOnWriteArrayList<OnGlobalLayoutListener> mOnGlobalLayoutListeners;
		private CopyOnWriteArrayList<OnTouchModeChangeListener> mOnTouchModeChangeListeners;
		private CopyOnWriteArrayList<OnComputeInternalInsetsListener> mOnComputeInternalInsetsListeners;
		private CopyOnWriteArrayList<OnScrollChangedListener> mOnScrollChangedListeners;
		private ArrayList<OnPreDrawListener> mOnPreDrawListeners;

		// Non-recursive listeners use CopyOnWriteArray
		// Any listener invoked from ViewRootImpl.performTraversals() should not be recursive
		private CopyOnWriteArray<OnGlobalLayoutListener> mOnGlobalLayoutListeners;
		private CopyOnWriteArray<OnComputeInternalInsetsListener> mOnComputeInternalInsetsListeners;
		private CopyOnWriteArray<OnScrollChangedListener> mOnScrollChangedListeners;
		private CopyOnWriteArray<OnPreDrawListener> mOnPreDrawListeners;

		// These listeners cannot be mutated during dispatch
		private ArrayList<OnDrawListener> mOnDrawListeners;

		private boolean mAlive = true;
		@@ -363,7 +369,7 @@ public final class ViewTreeObserver {
		checkIsAlive();

		if (mOnGlobalLayoutListeners == null) {
		mOnGlobalLayoutListeners = new CopyOnWriteArrayList<OnGlobalLayoutListener>();
		mOnGlobalLayoutListeners = new CopyOnWriteArray<OnGlobalLayoutListener>();
		}

		mOnGlobalLayoutListeners.add(listener);
		@@ -413,7 +419,7 @@ public final class ViewTreeObserver {
		checkIsAlive();

		if (mOnPreDrawListeners == null) {
		mOnPreDrawListeners = new ArrayList<OnPreDrawListener>();
		mOnPreDrawListeners = new CopyOnWriteArray<OnPreDrawListener>();
		}

		mOnPreDrawListeners.add(listener);
		@@ -485,7 +491,7 @@ public final class ViewTreeObserver {
		checkIsAlive();

		if (mOnScrollChangedListeners == null) {
		mOnScrollChangedListeners = new CopyOnWriteArrayList<OnScrollChangedListener>();
		mOnScrollChangedListeners = new CopyOnWriteArray<OnScrollChangedListener>();
		}

		mOnScrollChangedListeners.add(listener);
		@@ -558,7 +564,7 @@ public final class ViewTreeObserver {

		if (mOnComputeInternalInsetsListeners == null) {
		mOnComputeInternalInsetsListeners =
		new CopyOnWriteArrayList<OnComputeInternalInsetsListener>();
		new CopyOnWriteArray<OnComputeInternalInsetsListener>();
		}

		mOnComputeInternalInsetsListeners.add(listener);
		@@ -640,10 +646,16 @@ public final class ViewTreeObserver {
		// perform the dispatching. The iterator is a safe guard against listeners that
		// could mutate the list by calling the various add/remove methods. This prevents
		// the array from being modified while we iterate it.
		final CopyOnWriteArrayList<OnGlobalLayoutListener> listeners = mOnGlobalLayoutListeners;
		final CopyOnWriteArray<OnGlobalLayoutListener> listeners = mOnGlobalLayoutListeners;
		if (listeners != null && listeners.size() > 0) {
		for (OnGlobalLayoutListener listener : listeners) {
		listener.onGlobalLayout();
		CopyOnWriteArray.Access<OnGlobalLayoutListener> access = listeners.start();
		try {
		int count = access.size();
		for (int i = 0; i < count; i++) {
		access.get(i).onGlobalLayout();
		}
		} finally {
		listeners.end();
		}
		}
		}
		@@ -658,17 +670,17 @@ public final class ViewTreeObserver {
		*/
		@SuppressWarnings("unchecked")
		public final boolean dispatchOnPreDraw() {
		// NOTE: we must clone the listener list to perform the dispatching.
		// The clone is a safe guard against listeners that
		// could mutate the list by calling the various add/remove methods. This prevents
		// the array from being modified while we process it.
		boolean cancelDraw = false;
		if (mOnPreDrawListeners != null && mOnPreDrawListeners.size() > 0) {
		final ArrayList<OnPreDrawListener> listeners =
		(ArrayList<OnPreDrawListener>) mOnPreDrawListeners.clone();
		int numListeners = listeners.size();
		for (int i = 0; i < numListeners; ++i) {
		cancelDraw \|= !(listeners.get(i).onPreDraw());
		final CopyOnWriteArray<OnPreDrawListener> listeners = mOnPreDrawListeners;
		if (listeners != null && listeners.size() > 0) {
		CopyOnWriteArray.Access<OnPreDrawListener> access = listeners.start();
		try {
		int count = access.size();
		for (int i = 0; i < count; i++) {
		cancelDraw \|= !(access.get(i).onPreDraw());
		}
		} finally {
		listeners.end();
		}
		}
		return cancelDraw;
		@@ -710,10 +722,16 @@ public final class ViewTreeObserver {
		// perform the dispatching. The iterator is a safe guard against listeners that
		// could mutate the list by calling the various add/remove methods. This prevents
		// the array from being modified while we iterate it.
		final CopyOnWriteArrayList<OnScrollChangedListener> listeners = mOnScrollChangedListeners;
		final CopyOnWriteArray<OnScrollChangedListener> listeners = mOnScrollChangedListeners;
		if (listeners != null && listeners.size() > 0) {
		for (OnScrollChangedListener listener : listeners) {
		listener.onScrollChanged();
		CopyOnWriteArray.Access<OnScrollChangedListener> access = listeners.start();
		try {
		int count = access.size();
		for (int i = 0; i < count; i++) {
		access.get(i).onScrollChanged();
		}
		} finally {
		listeners.end();
		}
		}
		}
		@@ -722,7 +740,7 @@ public final class ViewTreeObserver {
		* Returns whether there are listeners for computing internal insets.
		*/
		final boolean hasComputeInternalInsetsListeners() {
		final CopyOnWriteArrayList<OnComputeInternalInsetsListener> listeners =
		final CopyOnWriteArray<OnComputeInternalInsetsListener> listeners =
		mOnComputeInternalInsetsListeners;
		return (listeners != null && listeners.size() > 0);
		}
		@@ -735,12 +753,105 @@ public final class ViewTreeObserver {
		// perform the dispatching. The iterator is a safe guard against listeners that
		// could mutate the list by calling the various add/remove methods. This prevents
		// the array from being modified while we iterate it.
		final CopyOnWriteArrayList<OnComputeInternalInsetsListener> listeners =
		final CopyOnWriteArray<OnComputeInternalInsetsListener> listeners =
		mOnComputeInternalInsetsListeners;
		if (listeners != null && listeners.size() > 0) {
		for (OnComputeInternalInsetsListener listener : listeners) {
		listener.onComputeInternalInsets(inoutInfo);
		CopyOnWriteArray.Access<OnComputeInternalInsetsListener> access = listeners.start();
		try {
		int count = access.size();
		for (int i = 0; i < count; i++) {
		access.get(i).onComputeInternalInsets(inoutInfo);
		}
		} finally {
		listeners.end();
		}
		}
		}

		/**
		* Copy on write array. This array is not thread safe, and only one loop can
		* iterate over this array at any given time. This class avoids allocations
		* until a concurrent modification happens.
		*
		* Usage:
		*
		* CopyOnWriteArray.Access<MyData> access = array.start();
		* try {
		* for (int i = 0; i < access.size(); i++) {
		* MyData d = access.get(i);
		* }
		* } finally {
		* access.end();
		* }
		*/
		static class CopyOnWriteArray<T> {
		private ArrayList<T> mData = new ArrayList<T>();
		private ArrayList<T> mDataCopy;

		private final Access<T> mAccess = new Access<T>();

		private boolean mStart;

		static class Access<T> {
		private ArrayList<T> mData;
		private int mSize;

		T get(int index) {
		return mData.get(index);
		}

		int size() {
		return mSize;
		}
		}

		CopyOnWriteArray() {
		}

		private ArrayList<T> getArray() {
		if (mStart) {
		if (mDataCopy == null) mDataCopy = new ArrayList<T>(mData);
		return mDataCopy;
		}
		return mData;
		}

		Access<T> start() {
		if (mStart) throw new IllegalStateException("Iteration already started");
		mStart = true;
		mDataCopy = null;
		mAccess.mData = mData;
		mAccess.mSize = mData.size();
		return mAccess;
		}

		void end() {
		if (!mStart) throw new IllegalStateException("Iteration not started");
		mStart = false;
		if (mDataCopy != null) {
		mData = mDataCopy;
		}
		mDataCopy = null;
		}

		int size() {
		return getArray().size();
		}

		void add(T item) {
		getArray().add(item);
		}

		void addAll(CopyOnWriteArray<T> array) {
		getArray().addAll(array.mData);
		}

		void remove(T item) {
		getArray().remove(item);
		}

		void clear() {
		getArray().clear();
		}
		}
		}