commit 28efc19d395bca5c747d71d392dfbeccf42b00be
author Prabir Pradhan <prabirmsp@google.com> Tue Nov 05 01:10:04 2019 +0000
committer Prabir Pradhan <prabirmsp@google.com> Wed Dec 04 13:48:58 2019 -0800
tree 32feafb201c5d1192abfc5e8b44bc428be37b406
parent cace66c539fc5c2c3451fa5af5c6324ddcc4e384

Reland "Let InputReader handle its own thread"

This CL was first landed in Ic732436d4f00a831e317be1f16ac106a11652cff
but was reverted due to flaky tests.

The flaky tests were caused by races between the instrumented test
classes and the InputReader class under test, which now runs in a new
thread.

In addition to re-landing the change, this CL ensures that InputReader
does not start its own thread in its unit tests, but instead keep using
the loopOnce method that is exposed for testing.

Bug: 130819454
Test: atest inputflinger_tests
Test: Touch input works on crosshatch
Change-Id: I5bbfc68b6be6745efc8b7106a9292ee3cb431c9c

services/inputflinger/reader/include/InputReader.h

diff --git a/services/inputflinger/reader/include/InputReader.h b/services/inputflinger/reader/include/InputReader.h
index 557eb3b..5024906 100644
--- a/services/inputflinger/reader/include/InputReader.h
+++ b/services/inputflinger/reader/include/InputReader.h
@@ -38,12 +38,12 @@
  * that it sends to the input listener.  Some functions of the input reader, such as early
  * event filtering in low power states, are controlled by a separate policy object.
  *
- * The InputReader owns a collection of InputMappers.  Most of the work it does happens
- * on the input reader thread but the InputReader can receive queries from other system
+ * The InputReader owns a collection of InputMappers. InputReader starts its own thread, where
+ * most of the work happens, but the InputReader can receive queries from other system
  * components running on arbitrary threads.  To keep things manageable, the InputReader
  * uses a single Mutex to guard its state.  The Mutex may be held while calling into the
  * EventHub or the InputReaderPolicy but it is never held while calling into the
- * InputListener.
+ * InputListener. All calls to InputListener must happen from InputReader's thread.
  */
 class InputReader : public InputReaderInterface {
 public:
@@ -55,7 +55,8 @@
     virtual void dump(std::string& dump) override;
     virtual void monitor() override;
 
-    virtual void loopOnce() override;
+    virtual status_t start() override;
+    virtual status_t stop() override;
 
     virtual void getInputDevices(std::vector<InputDeviceInfo>& outInputDevices) override;
 
@@ -86,6 +87,10 @@
                                             const InputDeviceIdentifier& identifier,
                                             uint32_t classes);
 
+    // With each iteration of the loop, InputReader reads and processes one incoming message from
+    // the EventHub.
+    void loopOnce();
+
     class ContextImpl : public InputReaderContext {
         InputReader* mReader;
 
@@ -111,6 +116,9 @@
     friend class ContextImpl;
 
 private:
+    class InputReaderThread;
+    sp<InputReaderThread> mThread;
+
     Mutex mLock;
 
     Condition mReaderIsAliveCondition;