Replace epoll() with poll() and rename PollLoop to Looper.

As part of this change, consolidated and cleaned up the Looper API so
that there are fewer distinctions between the NDK and non-NDK declarations
(no need for two callback types, etc.).

Removed the dependence on specific constants from sys/poll.h such as
POLLIN.  Instead looper.h defines events like LOOPER_EVENT_INPUT for
the events that it supports.  That should help make any future
under-the-hood implementation changes easier.

Fixed a couple of compiler warnings along the way.

Change-Id: I449a7ec780bf061bdd325452f823673e2b39b6ae
diff --git a/libs/utils/tests/Looper_test.cpp b/libs/utils/tests/Looper_test.cpp
new file mode 100644
index 0000000..afc92f8
--- /dev/null
+++ b/libs/utils/tests/Looper_test.cpp
@@ -0,0 +1,433 @@
+//
+// Copyright 2010 The Android Open Source Project
+//
+
+#include <utils/Looper.h>
+#include <utils/Timers.h>
+#include <utils/StopWatch.h>
+#include <gtest/gtest.h>
+#include <unistd.h>
+#include <time.h>
+
+#include "TestHelpers.h"
+
+// # of milliseconds to fudge stopwatch measurements
+#define TIMING_TOLERANCE_MS 25
+
+namespace android {
+
+class DelayedWake : public DelayedTask {
+    sp<Looper> mLooper;
+
+public:
+    DelayedWake(int delayMillis, const sp<Looper> looper) :
+        DelayedTask(delayMillis), mLooper(looper) {
+    }
+
+protected:
+    virtual void doTask() {
+        mLooper->wake();
+    }
+};
+
+class DelayedWriteSignal : public DelayedTask {
+    Pipe* mPipe;
+
+public:
+    DelayedWriteSignal(int delayMillis, Pipe* pipe) :
+        DelayedTask(delayMillis), mPipe(pipe) {
+    }
+
+protected:
+    virtual void doTask() {
+        mPipe->writeSignal();
+    }
+};
+
+class CallbackHandler {
+public:
+    void setCallback(const sp<Looper>& looper, int fd, int events) {
+        looper->addFd(fd, 0, events, staticHandler, this);
+    }
+
+protected:
+    virtual ~CallbackHandler() { }
+
+    virtual int handler(int fd, int events) = 0;
+
+private:
+    static int staticHandler(int fd, int events, void* data) {
+        return static_cast<CallbackHandler*>(data)->handler(fd, events);
+    }
+};
+
+class StubCallbackHandler : public CallbackHandler {
+public:
+    int nextResult;
+    int callbackCount;
+
+    int fd;
+    int events;
+
+    StubCallbackHandler(int nextResult) : nextResult(nextResult),
+            callbackCount(0), fd(-1), events(-1) {
+    }
+
+protected:
+    virtual int handler(int fd, int events) {
+        callbackCount += 1;
+        this->fd = fd;
+        this->events = events;
+        return nextResult;
+    }
+};
+
+class LooperTest : public testing::Test {
+protected:
+    sp<Looper> mLooper;
+
+    virtual void SetUp() {
+        mLooper = new Looper(true);
+    }
+
+    virtual void TearDown() {
+        mLooper.clear();
+    }
+};
+
+
+TEST_F(LooperTest, PollOnce_WhenNonZeroTimeoutAndNotAwoken_WaitsForTimeout) {
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal timeout";
+    EXPECT_EQ(ALOOPER_POLL_TIMEOUT, result)
+            << "pollOnce result should be ALOOPER_POLL_TIMEOUT";
+}
+
+TEST_F(LooperTest, PollOnce_WhenNonZeroTimeoutAndAwokenBeforeWaiting_ImmediatelyReturns) {
+    mLooper->wake();
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(1000);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. zero because wake() was called before waiting";
+    EXPECT_EQ(ALOOPER_POLL_WAKE, result)
+            << "pollOnce result should be ALOOPER_POLL_CALLBACK because loop was awoken";
+}
+
+TEST_F(LooperTest, PollOnce_WhenNonZeroTimeoutAndAwokenWhileWaiting_PromptlyReturns) {
+    sp<DelayedWake> delayedWake = new DelayedWake(100, mLooper);
+    delayedWake->run();
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(1000);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal wake delay";
+    EXPECT_EQ(ALOOPER_POLL_WAKE, result)
+            << "pollOnce result should be ALOOPER_POLL_CALLBACK because loop was awoken";
+}
+
+TEST_F(LooperTest, PollOnce_WhenZeroTimeoutAndNoRegisteredFDs_ImmediatelyReturns) {
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(0);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should be approx. zero";
+    EXPECT_EQ(ALOOPER_POLL_TIMEOUT, result)
+            << "pollOnce result should be ALOOPER_POLL_TIMEOUT";
+}
+
+TEST_F(LooperTest, PollOnce_WhenZeroTimeoutAndNoSignalledFDs_ImmediatelyReturns) {
+    Pipe pipe;
+    StubCallbackHandler handler(true);
+
+    handler.setCallback(mLooper, pipe.receiveFd, ALOOPER_EVENT_INPUT);
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(0);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should be approx. zero";
+    EXPECT_EQ(ALOOPER_POLL_TIMEOUT, result)
+            << "pollOnce result should be ALOOPER_POLL_TIMEOUT";
+    EXPECT_EQ(0, handler.callbackCount)
+            << "callback should not have been invoked because FD was not signalled";
+}
+
+TEST_F(LooperTest, PollOnce_WhenZeroTimeoutAndSignalledFD_ImmediatelyInvokesCallbackAndReturns) {
+    Pipe pipe;
+    StubCallbackHandler handler(true);
+
+    ASSERT_EQ(OK, pipe.writeSignal());
+    handler.setCallback(mLooper, pipe.receiveFd, ALOOPER_EVENT_INPUT);
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(0);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should be approx. zero";
+    EXPECT_EQ(ALOOPER_POLL_CALLBACK, result)
+            << "pollOnce result should be ALOOPER_POLL_CALLBACK because FD was signalled";
+    EXPECT_EQ(1, handler.callbackCount)
+            << "callback should be invoked exactly once";
+    EXPECT_EQ(pipe.receiveFd, handler.fd)
+            << "callback should have received pipe fd as parameter";
+    EXPECT_EQ(ALOOPER_EVENT_INPUT, handler.events)
+            << "callback should have received ALOOPER_EVENT_INPUT as events";
+}
+
+TEST_F(LooperTest, PollOnce_WhenNonZeroTimeoutAndNoSignalledFDs_WaitsForTimeoutAndReturns) {
+    Pipe pipe;
+    StubCallbackHandler handler(true);
+
+    handler.setCallback(mLooper, pipe.receiveFd, ALOOPER_EVENT_INPUT);
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    EXPECT_NEAR(100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal timeout";
+    EXPECT_EQ(ALOOPER_POLL_TIMEOUT, result)
+            << "pollOnce result should be ALOOPER_POLL_TIMEOUT";
+    EXPECT_EQ(0, handler.callbackCount)
+            << "callback should not have been invoked because FD was not signalled";
+}
+
+TEST_F(LooperTest, PollOnce_WhenNonZeroTimeoutAndSignalledFDBeforeWaiting_ImmediatelyInvokesCallbackAndReturns) {
+    Pipe pipe;
+    StubCallbackHandler handler(true);
+
+    pipe.writeSignal();
+    handler.setCallback(mLooper, pipe.receiveFd, ALOOPER_EVENT_INPUT);
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should be approx. zero";
+    EXPECT_EQ(ALOOPER_POLL_CALLBACK, result)
+            << "pollOnce result should be ALOOPER_POLL_CALLBACK because FD was signalled";
+    EXPECT_EQ(1, handler.callbackCount)
+            << "callback should be invoked exactly once";
+    EXPECT_EQ(pipe.receiveFd, handler.fd)
+            << "callback should have received pipe fd as parameter";
+    EXPECT_EQ(ALOOPER_EVENT_INPUT, handler.events)
+            << "callback should have received ALOOPER_EVENT_INPUT as events";
+}
+
+TEST_F(LooperTest, PollOnce_WhenNonZeroTimeoutAndSignalledFDWhileWaiting_PromptlyInvokesCallbackAndReturns) {
+    Pipe pipe;
+    StubCallbackHandler handler(true);
+    sp<DelayedWriteSignal> delayedWriteSignal = new DelayedWriteSignal(100, & pipe);
+
+    handler.setCallback(mLooper, pipe.receiveFd, ALOOPER_EVENT_INPUT);
+    delayedWriteSignal->run();
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(1000);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal signal delay";
+    EXPECT_EQ(ALOOPER_POLL_CALLBACK, result)
+            << "pollOnce result should be ALOOPER_POLL_CALLBACK because FD was signalled";
+    EXPECT_EQ(1, handler.callbackCount)
+            << "callback should be invoked exactly once";
+    EXPECT_EQ(pipe.receiveFd, handler.fd)
+            << "callback should have received pipe fd as parameter";
+    EXPECT_EQ(ALOOPER_EVENT_INPUT, handler.events)
+            << "callback should have received ALOOPER_EVENT_INPUT as events";
+}
+
+TEST_F(LooperTest, PollOnce_WhenCallbackAddedThenRemoved_CallbackShouldNotBeInvoked) {
+    Pipe pipe;
+    StubCallbackHandler handler(true);
+
+    handler.setCallback(mLooper, pipe.receiveFd, ALOOPER_EVENT_INPUT);
+    pipe.writeSignal(); // would cause FD to be considered signalled
+    mLooper->removeFd(pipe.receiveFd);
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(100, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal timeout because FD was no longer registered";
+    EXPECT_EQ(ALOOPER_POLL_TIMEOUT, result)
+            << "pollOnce result should be ALOOPER_POLL_TIMEOUT";
+    EXPECT_EQ(0, handler.callbackCount)
+            << "callback should not be invoked";
+}
+
+TEST_F(LooperTest, PollOnce_WhenCallbackReturnsFalse_CallbackShouldNotBeInvokedAgainLater) {
+    Pipe pipe;
+    StubCallbackHandler handler(false);
+
+    handler.setCallback(mLooper, pipe.receiveFd, ALOOPER_EVENT_INPUT);
+
+    // First loop: Callback is registered and FD is signalled.
+    pipe.writeSignal();
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(0);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal zero because FD was already signalled";
+    EXPECT_EQ(ALOOPER_POLL_CALLBACK, result)
+            << "pollOnce result should be ALOOPER_POLL_CALLBACK because FD was signalled";
+    EXPECT_EQ(1, handler.callbackCount)
+            << "callback should be invoked";
+
+    // Second loop: Callback is no longer registered and FD is signalled.
+    pipe.writeSignal();
+
+    stopWatch.reset();
+    result = mLooper->pollOnce(0);
+    elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. equal zero because timeout was zero";
+    EXPECT_EQ(ALOOPER_POLL_TIMEOUT, result)
+            << "pollOnce result should be ALOOPER_POLL_TIMEOUT";
+    EXPECT_EQ(1, handler.callbackCount)
+            << "callback should not be invoked this time";
+}
+
+TEST_F(LooperTest, PollOnce_WhenNonCallbackFdIsSignalled_ReturnsIdent) {
+    const int expectedIdent = 5;
+    void* expectedData = this;
+
+    Pipe pipe;
+
+    pipe.writeSignal();
+    mLooper->addFd(pipe.receiveFd, expectedIdent, ALOOPER_EVENT_INPUT, NULL, expectedData);
+
+    StopWatch stopWatch("pollOnce");
+    int fd;
+    int events;
+    void* data;
+    int result = mLooper->pollOnce(100, &fd, &events, &data);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should be approx. zero";
+    EXPECT_EQ(expectedIdent, result)
+            << "pollOnce result should be the ident of the FD that was signalled";
+    EXPECT_EQ(pipe.receiveFd, fd)
+            << "pollOnce should have returned the received pipe fd";
+    EXPECT_EQ(ALOOPER_EVENT_INPUT, events)
+            << "pollOnce should have returned ALOOPER_EVENT_INPUT as events";
+    EXPECT_EQ(expectedData, data)
+            << "pollOnce should have returned the data";
+}
+
+TEST_F(LooperTest, AddFd_WhenCallbackAdded_ReturnsOne) {
+    Pipe pipe;
+    int result = mLooper->addFd(pipe.receiveFd, 0, ALOOPER_EVENT_INPUT, NULL, NULL);
+
+    EXPECT_EQ(1, result)
+            << "addFd should return 1 because FD was added";
+}
+
+TEST_F(LooperTest, AddFd_WhenEventsIsZero_ReturnsError) {
+    Pipe pipe;
+    int result = mLooper->addFd(pipe.receiveFd, 0, 0, NULL, NULL);
+
+    EXPECT_EQ(-1, result)
+            << "addFd should return -1 because arguments were invalid";
+}
+
+TEST_F(LooperTest, AddFd_WhenIdentIsNegativeAndCallbackIsNull_ReturnsError) {
+    Pipe pipe;
+    int result = mLooper->addFd(pipe.receiveFd, -1, ALOOPER_EVENT_INPUT, NULL, NULL);
+
+    EXPECT_EQ(-1, result)
+            << "addFd should return -1 because arguments were invalid";
+}
+
+TEST_F(LooperTest, AddFd_WhenNoCallbackAndAllowNonCallbacksIsFalse_ReturnsError) {
+    Pipe pipe;
+    sp<Looper> looper = new Looper(false /*allowNonCallbacks*/);
+    int result = looper->addFd(pipe.receiveFd, 0, 0, NULL, NULL);
+
+    EXPECT_EQ(-1, result)
+            << "addFd should return -1 because arguments were invalid";
+}
+
+TEST_F(LooperTest, RemoveFd_WhenCallbackNotAdded_ReturnsZero) {
+    int result = mLooper->removeFd(1);
+
+    EXPECT_EQ(0, result)
+            << "removeFd should return 0 because FD not registered";
+}
+
+TEST_F(LooperTest, RemoveFd_WhenCallbackAddedThenRemovedTwice_ReturnsOnceFirstTimeAndReturnsZeroSecondTime) {
+    Pipe pipe;
+    StubCallbackHandler handler(false);
+    handler.setCallback(mLooper, pipe.receiveFd, ALOOPER_EVENT_INPUT);
+
+    // First time.
+    int result = mLooper->removeFd(pipe.receiveFd);
+
+    EXPECT_EQ(1, result)
+            << "removeFd should return 1 first time because FD was registered";
+
+    // Second time.
+    result = mLooper->removeFd(pipe.receiveFd);
+
+    EXPECT_EQ(0, result)
+            << "removeFd should return 0 second time because FD was no longer registered";
+}
+
+TEST_F(LooperTest, PollOnce_WhenCallbackAddedTwice_OnlySecondCallbackShouldBeInvoked) {
+    Pipe pipe;
+    StubCallbackHandler handler1(true);
+    StubCallbackHandler handler2(true);
+
+    handler1.setCallback(mLooper, pipe.receiveFd, ALOOPER_EVENT_INPUT);
+    handler2.setCallback(mLooper, pipe.receiveFd, ALOOPER_EVENT_INPUT); // replace it
+    pipe.writeSignal(); // would cause FD to be considered signalled
+
+    StopWatch stopWatch("pollOnce");
+    int result = mLooper->pollOnce(100);
+    int32_t elapsedMillis = ns2ms(stopWatch.elapsedTime());
+
+    ASSERT_EQ(OK, pipe.readSignal())
+            << "signal should actually have been written";
+    EXPECT_NEAR(0, elapsedMillis, TIMING_TOLERANCE_MS)
+            << "elapsed time should approx. zero because FD was already signalled";
+    EXPECT_EQ(ALOOPER_POLL_CALLBACK, result)
+            << "pollOnce result should be ALOOPER_POLL_CALLBACK because FD was signalled";
+    EXPECT_EQ(0, handler1.callbackCount)
+            << "original handler callback should not be invoked because it was replaced";
+    EXPECT_EQ(1, handler2.callbackCount)
+            << "replacement handler callback should be invoked";
+}
+
+
+} // namespace android