Prevent events from getting backlogged.

This change implements two heuristics.

1. When events are older than 10 seconds, they are dropped.

2. If the application is currently busy processing an event and
   the user touches a window belonging to a different application
   then we drop the currently queued events so the other application
   can start processing the gesture immediately.

Note that the system takes care of synthesizing cancelation events
automatically for any events that it drops.

Added some new handle types to allow the native dispatcher to
indirectly refer to the WindowManager's window state and app window
token.  This was done to enable the dispatcher to identify the
application to which each window belongs but it also eliminates
some lookup tables and linear searches through the window list
on each key press.

Bug: 3224911
Change-Id: I9dae8dfe23d195d76865f97011fe2f1d351e2940

1 files changed, 15 insertions, 10 deletions

diff --git a/services/java/com/android/server/InputManager.java b/services/java/com/android/server/InputManager.java
index 410b8c259b00..5c2048bd81f4 100644
--- a/services/java/com/android/server/InputManager.java
+++ b/services/java/com/android/server/InputManager.java
@@ -77,7 +77,7 @@ public class InputManager {
     private static native boolean nativeHasKeys(int deviceId, int sourceMask,
             int[] keyCodes, boolean[] keyExists);
     private static native void nativeRegisterInputChannel(InputChannel inputChannel,
-            boolean monitor);
+            InputWindowHandle inputWindowHandle, boolean monitor);
     private static native void nativeUnregisterInputChannel(InputChannel inputChannel);
     private static native int nativeInjectInputEvent(InputEvent event,
             int injectorPid, int injectorUid, int syncMode, int timeoutMillis);
@@ -240,7 +240,7 @@ public class InputManager {
         }
         
         InputChannel[] inputChannels = InputChannel.openInputChannelPair(inputChannelName);
-        nativeRegisterInputChannel(inputChannels[0], true);
+        nativeRegisterInputChannel(inputChannels[0], null, true);
         inputChannels[0].dispose(); // don't need to retain the Java object reference
         return inputChannels[1];
     }
@@ -248,13 +248,16 @@ public class InputManager {
     /**
      * Registers an input channel so that it can be used as an input event target.
      * @param inputChannel The input channel to register.
+     * @param inputWindowHandle The handle of the input window associated with the
+     * input channel, or null if none.
      */
-    public void registerInputChannel(InputChannel inputChannel) {
+    public void registerInputChannel(InputChannel inputChannel,
+            InputWindowHandle inputWindowHandle) {
         if (inputChannel == null) {
             throw new IllegalArgumentException("inputChannel must not be null.");
         }
         
-        nativeRegisterInputChannel(inputChannel, false);
+        nativeRegisterInputChannel(inputChannel, inputWindowHandle, false);
     }
     
     /**
@@ -429,13 +432,15 @@ public class InputManager {
         }
         
         @SuppressWarnings("unused")
-        public void notifyInputChannelBroken(InputChannel inputChannel) {
-            mWindowManagerService.mInputMonitor.notifyInputChannelBroken(inputChannel);
+        public void notifyInputChannelBroken(InputWindowHandle inputWindowHandle) {
+            mWindowManagerService.mInputMonitor.notifyInputChannelBroken(inputWindowHandle);
         }
         
         @SuppressWarnings("unused")
-        public long notifyANR(Object token, InputChannel inputChannel) {
-            return mWindowManagerService.mInputMonitor.notifyANR(token, inputChannel);
+        public long notifyANR(InputApplicationHandle inputApplicationHandle,
+                InputWindowHandle inputWindowHandle) {
+            return mWindowManagerService.mInputMonitor.notifyANR(
+                    inputApplicationHandle, inputWindowHandle);
         }
         
         @SuppressWarnings("unused")
@@ -445,14 +450,14 @@ public class InputManager {
         }
         
         @SuppressWarnings("unused")
-        public boolean interceptKeyBeforeDispatching(InputChannel focus,
+        public boolean interceptKeyBeforeDispatching(InputWindowHandle focus,
                 KeyEvent event, int policyFlags) {
             return mWindowManagerService.mInputMonitor.interceptKeyBeforeDispatching(
                     focus, event, policyFlags);
         }
         
         @SuppressWarnings("unused")
-        public KeyEvent dispatchUnhandledKey(InputChannel focus,
+        public KeyEvent dispatchUnhandledKey(InputWindowHandle focus,
                 KeyEvent event, int policyFlags) {
             return mWindowManagerService.mInputMonitor.dispatchUnhandledKey(
                     focus, event, policyFlags);