Remove ViewTreeObserver allocations
A couple of allocations remain to handle possibly recursive listeners.
Change-Id: I72fd271c2fc4f4ad427a27e0665f780cae117aea
diff --git a/core/java/android/view/ViewTreeObserver.java b/core/java/android/view/ViewTreeObserver.java
index 1c5d436..cfcf3c0 100644
--- a/core/java/android/view/ViewTreeObserver.java
+++ b/core/java/android/view/ViewTreeObserver.java
@@ -32,12 +32,18 @@
* 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;
@@ -147,7 +153,7 @@
* windows behind it should be placed.
*/
public final Rect contentInsets = new Rect();
-
+
/**
* Offsets from the frame of the window at which windows behind it
* are visible.
@@ -166,13 +172,13 @@
* can be touched.
*/
public static final int TOUCHABLE_INSETS_FRAME = 0;
-
+
/**
* Option for {@link #setTouchableInsets(int)}: the area inside of
* the content insets can be touched.
*/
public static final int TOUCHABLE_INSETS_CONTENT = 1;
-
+
/**
* Option for {@link #setTouchableInsets(int)}: the area inside of
* the visible insets can be touched.
@@ -195,7 +201,7 @@
}
int mTouchableInsets;
-
+
void reset() {
contentInsets.setEmpty();
visibleInsets.setEmpty();
@@ -231,7 +237,7 @@
mTouchableInsets = other.mTouchableInsets;
}
}
-
+
/**
* Interface definition for a callback to be invoked when layout has
* completed and the client can compute its interior insets.
@@ -363,7 +369,7 @@
checkIsAlive();
if (mOnGlobalLayoutListeners == null) {
- mOnGlobalLayoutListeners = new CopyOnWriteArrayList<OnGlobalLayoutListener>();
+ mOnGlobalLayoutListeners = new CopyOnWriteArray<OnGlobalLayoutListener>();
}
mOnGlobalLayoutListeners.add(listener);
@@ -413,7 +419,7 @@
checkIsAlive();
if (mOnPreDrawListeners == null) {
- mOnPreDrawListeners = new ArrayList<OnPreDrawListener>();
+ mOnPreDrawListeners = new CopyOnWriteArray<OnPreDrawListener>();
}
mOnPreDrawListeners.add(listener);
@@ -485,7 +491,7 @@
checkIsAlive();
if (mOnScrollChangedListeners == null) {
- mOnScrollChangedListeners = new CopyOnWriteArrayList<OnScrollChangedListener>();
+ mOnScrollChangedListeners = new CopyOnWriteArray<OnScrollChangedListener>();
}
mOnScrollChangedListeners.add(listener);
@@ -558,7 +564,7 @@
if (mOnComputeInternalInsetsListeners == null) {
mOnComputeInternalInsetsListeners =
- new CopyOnWriteArrayList<OnComputeInternalInsetsListener>();
+ new CopyOnWriteArray<OnComputeInternalInsetsListener>();
}
mOnComputeInternalInsetsListeners.add(listener);
@@ -640,10 +646,16 @@
// 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 @@
*/
@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 @@
// 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();
}
}
}
@@ -722,11 +740,11 @@
* 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);
}
-
+
/**
* Calls all listeners to compute the current insets.
*/
@@ -735,12 +753,105 @@
// 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();
+ }
+ }
}