Add input filter mechanism for accessibility.

This patch adds a mechanism for capturing, filtering, transforming
and injecting input events at a very low level before the input
dispatcher attempts to deliver them to applications.  At this time,
the mechanism is only intended to be used by the accessibility
system to implement built-in system-level accessibility affordances.

The accessibility input filter is currently just a stub.
It logs the input events receives and reinjects them unchanged,
except that it transforms KEYCODE_Q into KEYCODE_Z.

Currently, the accessibility input filter is installed whenever
accessibility is enabled.  We'll probably want to change that
so it only enables the input filter when a screen reader is
installed and we want touch exploration.

Change-Id: I35764fdf75522b69d09ebd78c9766eb7593c1afe

2 files changed, 22 insertions, 13 deletions

diff --git a/services/input/tests/InputDispatcher_test.cpp b/services/input/tests/InputDispatcher_test.cpp
index 2f846c4..3650da0 100644
--- a/services/input/tests/InputDispatcher_test.cpp
+++ b/services/input/tests/InputDispatcher_test.cpp
@@ -67,6 +67,10 @@ private:
         return 60;
     }
 
+    virtual bool filterInputEvent(const InputEvent* inputEvent, uint32_t policyFlags) {
+        return true;
+    }
+
     virtual void interceptKeyBeforeQueueing(const KeyEvent* keyEvent, uint32_t& policyFlags) {
     }
 
@@ -124,7 +128,7 @@ TEST_F(InputDispatcherTest, InjectInputEvent_ValidatesKeyEvents) {
             /*action*/ -1, 0,
             AKEYCODE_A, KEY_A, AMETA_NONE, 0, ARBITRARY_TIME, ARBITRARY_TIME);
     ASSERT_EQ(INPUT_EVENT_INJECTION_FAILED, mDispatcher->injectInputEvent(&event,
-            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0))
+            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0, 0))
             << "Should reject key events with undefined action.";
 
     // Rejects ACTION_MULTIPLE since it is not supported despite being defined in the API.
@@ -132,7 +136,7 @@ TEST_F(InputDispatcherTest, InjectInputEvent_ValidatesKeyEvents) {
             AKEY_EVENT_ACTION_MULTIPLE, 0,
             AKEYCODE_A, KEY_A, AMETA_NONE, 0, ARBITRARY_TIME, ARBITRARY_TIME);
     ASSERT_EQ(INPUT_EVENT_INJECTION_FAILED, mDispatcher->injectInputEvent(&event,
-            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0))
+            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0, 0))
             << "Should reject key events with ACTION_MULTIPLE.";
 }
 
@@ -150,7 +154,7 @@ TEST_F(InputDispatcherTest, InjectInputEvent_ValidatesMotionEvents) {
             ARBITRARY_TIME, ARBITRARY_TIME,
             /*pointerCount*/ 1, pointerIds, pointerCoords);
     ASSERT_EQ(INPUT_EVENT_INJECTION_FAILED, mDispatcher->injectInputEvent(&event,
-            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0))
+            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0, 0))
             << "Should reject motion events with undefined action.";
 
     // Rejects pointer down with invalid index.
@@ -160,7 +164,7 @@ TEST_F(InputDispatcherTest, InjectInputEvent_ValidatesMotionEvents) {
             ARBITRARY_TIME, ARBITRARY_TIME,
             /*pointerCount*/ 1, pointerIds, pointerCoords);
     ASSERT_EQ(INPUT_EVENT_INJECTION_FAILED, mDispatcher->injectInputEvent(&event,
-            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0))
+            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0, 0))
             << "Should reject motion events with pointer down index too large.";
 
     event.initialize(DEVICE_ID, AINPUT_SOURCE_TOUCHSCREEN,
@@ -169,7 +173,7 @@ TEST_F(InputDispatcherTest, InjectInputEvent_ValidatesMotionEvents) {
             ARBITRARY_TIME, ARBITRARY_TIME,
             /*pointerCount*/ 1, pointerIds, pointerCoords);
     ASSERT_EQ(INPUT_EVENT_INJECTION_FAILED, mDispatcher->injectInputEvent(&event,
-            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0))
+            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0, 0))
             << "Should reject motion events with pointer down index too small.";
 
     // Rejects pointer up with invalid index.
@@ -179,7 +183,7 @@ TEST_F(InputDispatcherTest, InjectInputEvent_ValidatesMotionEvents) {
             ARBITRARY_TIME, ARBITRARY_TIME,
             /*pointerCount*/ 1, pointerIds, pointerCoords);
     ASSERT_EQ(INPUT_EVENT_INJECTION_FAILED, mDispatcher->injectInputEvent(&event,
-            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0))
+            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0, 0))
             << "Should reject motion events with pointer up index too large.";
 
     event.initialize(DEVICE_ID, AINPUT_SOURCE_TOUCHSCREEN,
@@ -188,7 +192,7 @@ TEST_F(InputDispatcherTest, InjectInputEvent_ValidatesMotionEvents) {
             ARBITRARY_TIME, ARBITRARY_TIME,
             /*pointerCount*/ 1, pointerIds, pointerCoords);
     ASSERT_EQ(INPUT_EVENT_INJECTION_FAILED, mDispatcher->injectInputEvent(&event,
-            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0))
+            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0, 0))
             << "Should reject motion events with pointer up index too small.";
 
     // Rejects motion events with invalid number of pointers.
@@ -197,7 +201,7 @@ TEST_F(InputDispatcherTest, InjectInputEvent_ValidatesMotionEvents) {
             ARBITRARY_TIME, ARBITRARY_TIME,
             /*pointerCount*/ 0, pointerIds, pointerCoords);
     ASSERT_EQ(INPUT_EVENT_INJECTION_FAILED, mDispatcher->injectInputEvent(&event,
-            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0))
+            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0, 0))
             << "Should reject motion events with 0 pointers.";
 
     event.initialize(DEVICE_ID, AINPUT_SOURCE_TOUCHSCREEN,
@@ -205,7 +209,7 @@ TEST_F(InputDispatcherTest, InjectInputEvent_ValidatesMotionEvents) {
             ARBITRARY_TIME, ARBITRARY_TIME,
             /*pointerCount*/ MAX_POINTERS + 1, pointerIds, pointerCoords);
     ASSERT_EQ(INPUT_EVENT_INJECTION_FAILED, mDispatcher->injectInputEvent(&event,
-            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0))
+            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0, 0))
             << "Should reject motion events with more than MAX_POINTERS pointers.";
 
     // Rejects motion events with invalid pointer ids.
@@ -215,7 +219,7 @@ TEST_F(InputDispatcherTest, InjectInputEvent_ValidatesMotionEvents) {
             ARBITRARY_TIME, ARBITRARY_TIME,
             /*pointerCount*/ 1, pointerIds, pointerCoords);
     ASSERT_EQ(INPUT_EVENT_INJECTION_FAILED, mDispatcher->injectInputEvent(&event,
-            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0))
+            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0, 0))
             << "Should reject motion events with pointer ids less than 0.";
 
     pointerIds[0] = MAX_POINTER_ID + 1;
@@ -224,7 +228,7 @@ TEST_F(InputDispatcherTest, InjectInputEvent_ValidatesMotionEvents) {
             ARBITRARY_TIME, ARBITRARY_TIME,
             /*pointerCount*/ 1, pointerIds, pointerCoords);
     ASSERT_EQ(INPUT_EVENT_INJECTION_FAILED, mDispatcher->injectInputEvent(&event,
-            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0))
+            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0, 0))
             << "Should reject motion events with pointer ids greater than MAX_POINTER_ID.";
 
     // Rejects motion events with duplicate pointer ids.
@@ -235,7 +239,7 @@ TEST_F(InputDispatcherTest, InjectInputEvent_ValidatesMotionEvents) {
             ARBITRARY_TIME, ARBITRARY_TIME,
             /*pointerCount*/ 2, pointerIds, pointerCoords);
     ASSERT_EQ(INPUT_EVENT_INJECTION_FAILED, mDispatcher->injectInputEvent(&event,
-            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0))
+            INJECTOR_PID, INJECTOR_UID, INPUT_EVENT_INJECTION_SYNC_NONE, 0, 0))
             << "Should reject motion events with duplicate pointer ids.";
 }
 
diff --git a/services/input/tests/InputReader_test.cpp b/services/input/tests/InputReader_test.cpp
index 60549c6..4c5f239 100644
--- a/services/input/tests/InputReader_test.cpp
+++ b/services/input/tests/InputReader_test.cpp
@@ -369,7 +369,8 @@ private:
     }
 
     virtual int32_t injectInputEvent(const InputEvent* event,
-            int32_t injectorPid, int32_t injectorUid, int32_t syncMode, int32_t timeoutMillis) {
+            int32_t injectorPid, int32_t injectorUid, int32_t syncMode, int32_t timeoutMillis,
+            uint32_t policyFlags) {
         ADD_FAILURE() << "Should never be called by input reader.";
         return INPUT_EVENT_INJECTION_FAILED;
     }
@@ -386,6 +387,10 @@ private:
         ADD_FAILURE() << "Should never be called by input reader.";
     }
 
+    virtual void setInputFilterEnabled(bool enabled) {
+        ADD_FAILURE() << "Should never be called by input reader.";
+    }
+
     virtual bool transferTouchFocus(const sp<InputChannel>& fromChannel,
             const sp<InputChannel>& toChannel) {
         ADD_FAILURE() << "Should never be called by input reader.";