Create InputThread to manage inputflinger threads

InputReader and InputDispatcher both manage their own threads. To help
manage input processing threads that have elevated priority/nice values,
we create the InputThread class.

Creating an InputThread starts the thread immediately, and loops the
loop function until the InputThread object is destructed.

Bug: 130819454
Test: atest inputflinger_tests
Test: Touch input works on crosshatch
Change-Id: I2cb56250fc62300e195c5b2474d32c2db3fa4711

7 files changed, 127 insertions, 68 deletions

diff --git a/services/inputflinger/Android.bp b/services/inputflinger/Android.bp
index f6b5935bcf..308e93aa48 100644
--- a/services/inputflinger/Android.bp
+++ b/services/inputflinger/Android.bp
@@ -83,6 +83,7 @@ cc_library_shared {
     srcs: [
         "InputListener.cpp",
         "InputReaderBase.cpp",
+        "InputThread.cpp",
     ],
 
     shared_libs: [
diff --git a/services/inputflinger/InputThread.cpp b/services/inputflinger/InputThread.cpp
new file mode 100644
index 0000000000..b87f7a1243
--- /dev/null
+++ b/services/inputflinger/InputThread.cpp
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "InputThread.h"
+
+namespace android {
+
+namespace {
+
+// Implementation of Thread from libutils.
+class InputThreadImpl : public Thread {
+public:
+    explicit InputThreadImpl(std::function<void()> loop)
+          : Thread(/* canCallJava */ true), mThreadLoop(loop) {}
+
+    ~InputThreadImpl() {}
+
+private:
+    std::function<void()> mThreadLoop;
+
+    bool threadLoop() override {
+        mThreadLoop();
+        return true;
+    }
+};
+
+} // namespace
+
+InputThread::InputThread(std::string name, std::function<void()> loop, std::function<void()> wake)
+      : mName(name), mThreadWake(wake) {
+    mThread = new InputThreadImpl(loop);
+    mThread->run(mName.c_str(), ANDROID_PRIORITY_URGENT_DISPLAY);
+}
+
+InputThread::~InputThread() {
+    mThread->requestExit();
+    if (mThreadWake) {
+        mThreadWake();
+    }
+    mThread->requestExitAndWait();
+}
+
+bool InputThread::isCallingThread() {
+    return gettid() == mThread->getTid();
+}
+
+} // namespace android
\ No newline at end of file
diff --git a/services/inputflinger/dispatcher/InputDispatcher.cpp b/services/inputflinger/dispatcher/InputDispatcher.cpp
index 30fdf906fc..6a56d38298 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.cpp
+++ b/services/inputflinger/dispatcher/InputDispatcher.cpp
@@ -325,24 +325,6 @@ static std::unique_ptr<DispatchEntry> createDispatchEntry(const InputTarget& inp
     return dispatchEntry;
 }
 
-// --- InputDispatcherThread ---
-
-class InputDispatcher::InputDispatcherThread : public Thread {
-public:
-    explicit InputDispatcherThread(InputDispatcher* dispatcher)
-          : Thread(/* canCallJava */ true), mDispatcher(dispatcher) {}
-
-    ~InputDispatcherThread() {}
-
-private:
-    InputDispatcher* mDispatcher;
-
-    virtual bool threadLoop() override {
-        mDispatcher->dispatchOnce();
-        return true;
-    }
-};
-
 // --- InputDispatcher ---
 
 InputDispatcher::InputDispatcher(const sp<InputDispatcherPolicyInterface>& policy)
@@ -367,8 +349,6 @@ InputDispatcher::InputDispatcher(const sp<InputDispatcherPolicyInterface>& polic
     mKeyRepeatState.lastKeyEntry = nullptr;
 
     policy->getDispatcherConfiguration(&mConfig);
-
-    mThread = new InputDispatcherThread(this);
 }
 
 InputDispatcher::~InputDispatcher() {
@@ -387,25 +367,21 @@ InputDispatcher::~InputDispatcher() {
 }
 
 status_t InputDispatcher::start() {
-    if (mThread->isRunning()) {
+    if (mThread) {
         return ALREADY_EXISTS;
     }
-    return mThread->run("InputDispatcher", PRIORITY_URGENT_DISPLAY);
+    mThread = std::make_unique<InputThread>(
+            "InputDispatcher", [this]() { dispatchOnce(); }, [this]() { mLooper->wake(); });
+    return OK;
 }
 
 status_t InputDispatcher::stop() {
-    if (!mThread->isRunning()) {
-        return OK;
-    }
-    if (gettid() == mThread->getTid()) {
-        ALOGE("InputDispatcher can only be stopped from outside of the InputDispatcherThread!");
+    if (mThread && mThread->isCallingThread()) {
+        ALOGE("InputDispatcher cannot be stopped from its own thread!");
         return INVALID_OPERATION;
     }
-    // Directly calling requestExitAndWait() causes the thread to not exit
-    // if mLooper is waiting for a long timeout.
-    mThread->requestExit();
-    mLooper->wake();
-    return mThread->requestExitAndWait();
+    mThread.reset();
+    return OK;
 }
 
 void InputDispatcher::dispatchOnce() {
diff --git a/services/inputflinger/dispatcher/InputDispatcher.h b/services/inputflinger/dispatcher/InputDispatcher.h
index a4ba0dec6a..93de18d02f 100644
--- a/services/inputflinger/dispatcher/InputDispatcher.h
+++ b/services/inputflinger/dispatcher/InputDispatcher.h
@@ -25,6 +25,7 @@
 #include "InputDispatcherPolicyInterface.h"
 #include "InputState.h"
 #include "InputTarget.h"
+#include "InputThread.h"
 #include "Monitor.h"
 #include "TouchState.h"
 #include "TouchedWindow.h"
@@ -124,8 +125,7 @@ private:
         STALE,
     };
 
-    class InputDispatcherThread;
-    sp<InputDispatcherThread> mThread;
+    std::unique_ptr<InputThread> mThread;
 
     sp<InputDispatcherPolicyInterface> mPolicy;
     android::InputDispatcherConfiguration mConfig;
diff --git a/services/inputflinger/include/InputThread.h b/services/inputflinger/include/InputThread.h
new file mode 100644
index 0000000000..407365a269
--- /dev/null
+++ b/services/inputflinger/include/InputThread.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _UI_INPUT_THREAD_H
+#define _UI_INPUT_THREAD_H
+
+#include <utils/Thread.h>
+
+namespace android {
+
+/* A thread that loops continuously until destructed to process input events.
+ *
+ * Creating the InputThread starts it immediately. The thread begins looping the loop
+ * function until the InputThread is destroyed. The wake function is used to wake anything
+ * that sleeps in the loop when it is time for the thread to be destroyed.
+ */
+class InputThread {
+public:
+    explicit InputThread(std::string name, std::function<void()> loop,
+                         std::function<void()> wake = nullptr);
+    virtual ~InputThread();
+
+    bool isCallingThread();
+
+private:
+    std::string mName;
+    std::function<void()> mThreadWake;
+    sp<Thread> mThread;
+};
+
+} // namespace android
+
+#endif // _UI_INPUT_THREAD_H
\ No newline at end of file
diff --git a/services/inputflinger/reader/InputReader.cpp b/services/inputflinger/reader/InputReader.cpp
index 05f0db1329..2023c6e8da 100644
--- a/services/inputflinger/reader/InputReader.cpp
+++ b/services/inputflinger/reader/InputReader.cpp
@@ -49,25 +49,6 @@ using android::base::StringPrintf;
 
 namespace android {
 
-// --- InputReader::InputReaderThread ---
-
-/* Thread that reads raw events from the event hub and processes them, endlessly. */
-class InputReader::InputReaderThread : public Thread {
-public:
-    explicit InputReaderThread(InputReader* reader)
-          : Thread(/* canCallJava */ true), mReader(reader) {}
-
-    ~InputReaderThread() {}
-
-private:
-    InputReader* mReader;
-
-    bool threadLoop() override {
-        mReader->loopOnce();
-        return true;
-    }
-};
-
 // --- InputReader ---
 
 InputReader::InputReader(std::shared_ptr<EventHubInterface> eventHub,
@@ -83,7 +64,6 @@ InputReader::InputReader(std::shared_ptr<EventHubInterface> eventHub,
         mNextTimeout(LLONG_MAX),
         mConfigurationChangesToRefresh(0) {
     mQueuedListener = new QueuedInputListener(listener);
-    mThread = new InputReaderThread(this);
 
     { // acquire lock
         AutoMutex _l(mLock);
@@ -100,25 +80,21 @@ InputReader::~InputReader() {
 }
 
 status_t InputReader::start() {
-    if (mThread->isRunning()) {
+    if (mThread) {
         return ALREADY_EXISTS;
     }
-    return mThread->run("InputReader", PRIORITY_URGENT_DISPLAY);
+    mThread = std::make_unique<InputThread>(
+            "InputReader", [this]() { loopOnce(); }, [this]() { mEventHub->wake(); });
+    return OK;
 }
 
 status_t InputReader::stop() {
-    if (!mThread->isRunning()) {
-        return OK;
-    }
-    if (gettid() == mThread->getTid()) {
-        ALOGE("InputReader can only be stopped from outside of the InputReaderThread!");
+    if (mThread && mThread->isCallingThread()) {
+        ALOGE("InputReader cannot be stopped from its own thread!");
         return INVALID_OPERATION;
     }
-    // Directly calling requestExitAndWait() causes the thread to not exit
-    // if mEventHub is waiting for a long timeout.
-    mThread->requestExit();
-    mEventHub->wake();
-    return mThread->requestExitAndWait();
+    mThread.reset();
+    return OK;
 }
 
 void InputReader::loopOnce() {
diff --git a/services/inputflinger/reader/include/InputReader.h b/services/inputflinger/reader/include/InputReader.h
index 502490601e..02957cd6ee 100644
--- a/services/inputflinger/reader/include/InputReader.h
+++ b/services/inputflinger/reader/include/InputReader.h
@@ -21,6 +21,7 @@
 #include "InputListener.h"
 #include "InputReaderBase.h"
 #include "InputReaderContext.h"
+#include "InputThread.h"
 
 #include <utils/Condition.h>
 #include <utils/Mutex.h>
@@ -116,8 +117,7 @@ protected:
     friend class ContextImpl;
 
 private:
-    class InputReaderThread;
-    sp<InputReaderThread> mThread;
+    std::unique_ptr<InputThread> mThread;
 
     Mutex mLock;