Add InputChannel::waitForMessage and use it in EndToEndNativeInputTest

The EndToEndNativeInputTest::waitForEventAvailable(timeoutMs) is similar
in implementation to InputChannel::probablyHasInput(), but can stop
after a timeout.

Add InputChannel::waitForMessage(std::chrono::milliseconds timeout) for
use in tests and use it to replace the waitForEventAvailable().

The difference of the new method from probablyHasInput() is that the
latter does not get repeated (because it is not necessary to implement
the hint). Repeating happens only on EINTR to allow tests to return
before timeout expiration when there are problems with the channel
setup. In the end the implementations are rather different.

Bug: b/314973388
Test: atest frameworks/native/libs/gui/tests/EndToEndNativeInputTest.cpp
Test: atest InputPublisherAndConsumerTest
Change-Id: I806aad14e4fba223a5cbbe49cea862f9b8279f24

3 files changed, 51 insertions, 33 deletions

diff --git a/include/input/InputTransport.h b/include/input/InputTransport.h
index 750e170c24..2d64872beb 100644
--- a/include/input/InputTransport.h
+++ b/include/input/InputTransport.h
@@ -290,6 +290,17 @@ public:
      */
     bool probablyHasInput() const;
 
+    /* Wait until there is a message in the channel.
+     *
+     * The |timeout| specifies how long to block waiting for an input event to appear. Negative
+     * values are not allowed.
+     *
+     * In some cases returning before timeout expiration can happen without a message available.
+     * This could happen after the channel was closed on the other side. Another possible reason
+     * is incorrect setup of the channel.
+     */
+    void waitForMessage(std::chrono::milliseconds timeout) const;
+
     /* Return a new object that has a duplicate of this channel's fd. */
     std::unique_ptr<InputChannel> dup() const;
 
diff --git a/libs/gui/tests/EndToEndNativeInputTest.cpp b/libs/gui/tests/EndToEndNativeInputTest.cpp
index d4b8dbeeb9..b9ab803101 100644
--- a/libs/gui/tests/EndToEndNativeInputTest.cpp
+++ b/libs/gui/tests/EndToEndNativeInputTest.cpp
@@ -168,8 +168,8 @@ public:
         return std::make_unique<InputSurface>(surfaceControl, width, height);
     }
 
-    InputEvent *consumeEvent(int timeoutMs = 3000) {
-        waitForEventAvailable(timeoutMs);
+    InputEvent* consumeEvent(std::chrono::milliseconds timeout = 3000ms) {
+        mClientChannel->waitForMessage(timeout);
 
         InputEvent *ev;
         uint32_t seqId;
@@ -302,15 +302,6 @@ public:
         t.apply(true);
     }
 
-private:
-    void waitForEventAvailable(int timeoutMs) {
-        struct pollfd fd;
-
-        fd.fd = mClientChannel->getFd();
-        fd.events = POLLIN;
-        poll(&fd, 1, timeoutMs);
-    }
-
 public:
     sp<SurfaceControl> mSurfaceControl;
     std::shared_ptr<InputChannel> mClientChannel;
@@ -615,7 +606,7 @@ TEST_F(InputSurfacesTest, touchable_region) {
 
     // A tap within the surface but outside the touchable region should not be sent to the surface.
     injectTap(20, 30);
-    EXPECT_EQ(surface->consumeEvent(200 /*timeoutMs*/), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/200ms), nullptr);
 
     injectTap(31, 52);
     surface->expectTap(20, 30);
@@ -981,12 +972,12 @@ TEST_F(InputSurfacesTest, strict_unobscured_input_obscured_window) {
     obscuringSurface->mInputInfo.ownerUid = gui::Uid{22222};
     obscuringSurface->showAt(100, 100);
     injectTap(101, 101);
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 
     surface->requestFocus();
     surface->assertFocusChange(true);
     injectKey(AKEYCODE_V);
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 }
 
 TEST_F(InputSurfacesTest, strict_unobscured_input_partially_obscured_window) {
@@ -1002,12 +993,12 @@ TEST_F(InputSurfacesTest, strict_unobscured_input_partially_obscured_window) {
 
     injectTap(101, 101);
 
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 
     surface->requestFocus();
     surface->assertFocusChange(true);
     injectKey(AKEYCODE_V);
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 }
 
 TEST_F(InputSurfacesTest, strict_unobscured_input_alpha_window) {
@@ -1024,12 +1015,12 @@ TEST_F(InputSurfacesTest, strict_unobscured_input_alpha_window) {
 
     injectTap(101, 101);
 
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 
     surface->requestFocus();
     surface->assertFocusChange(true);
     injectKey(AKEYCODE_V);
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 }
 
 TEST_F(InputSurfacesTest, strict_unobscured_input_cropped_window) {
@@ -1046,12 +1037,12 @@ TEST_F(InputSurfacesTest, strict_unobscured_input_cropped_window) {
 
     injectTap(111, 111);
 
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 
     surface->requestFocus();
     surface->assertFocusChange(true);
     injectKey(AKEYCODE_V);
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 }
 
 TEST_F(InputSurfacesTest, ignore_touch_region_with_zero_sized_blast) {
@@ -1076,12 +1067,12 @@ TEST_F(InputSurfacesTest, drop_input_policy) {
 
     injectTap(101, 101);
 
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 
     surface->requestFocus();
     surface->assertFocusChange(true);
     injectKey(AKEYCODE_V);
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 }
 
 TEST_F(InputSurfacesTest, layer_with_valid_crop_can_be_focused) {
@@ -1116,7 +1107,7 @@ TEST_F(InputSurfacesTest, cropped_container_replaces_touchable_region_with_null_
 
     // Does not receive events outside its crop
     injectTap(26, 26);
-    EXPECT_EQ(containerSurface->consumeEvent(100), nullptr);
+    EXPECT_EQ(containerSurface->consumeEvent(/*timeout=*/100ms), nullptr);
 }
 
 /**
@@ -1141,7 +1132,7 @@ TEST_F(InputSurfacesTest, uncropped_container_replaces_touchable_region_with_nul
 
     // Does not receive events outside parent bounds
     injectTap(31, 31);
-    EXPECT_EQ(containerSurface->consumeEvent(100), nullptr);
+    EXPECT_EQ(containerSurface->consumeEvent(/*timeout=*/100ms), nullptr);
 }
 
 /**
@@ -1167,7 +1158,7 @@ TEST_F(InputSurfacesTest, replace_touchable_region_with_crop) {
     // Does not receive events outside crop layer bounds
     injectTap(21, 21);
     injectTap(71, 71);
-    EXPECT_EQ(containerSurface->consumeEvent(100), nullptr);
+    EXPECT_EQ(containerSurface->consumeEvent(/*timeout=*/100ms), nullptr);
 }
 
 TEST_F(InputSurfacesTest, child_container_with_no_input_channel_blocks_parent) {
@@ -1184,7 +1175,7 @@ TEST_F(InputSurfacesTest, child_container_with_no_input_channel_blocks_parent) {
             [&](auto &t, auto &sc) { t.reparent(sc, parent->mSurfaceControl); });
     injectTap(101, 101);
 
-    EXPECT_EQ(parent->consumeEvent(100), nullptr);
+    EXPECT_EQ(parent->consumeEvent(/*timeout=*/100ms), nullptr);
 }
 
 class MultiDisplayTests : public InputSurfacesTest {
@@ -1233,7 +1224,7 @@ TEST_F(MultiDisplayTests, drop_touch_if_layer_on_invalid_display) {
 
     // Touches should be dropped if the layer is on an invalid display.
     injectTapOnDisplay(101, 101, layerStack.id);
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 
     // However, we still let the window be focused and receive keys.
     surface->requestFocus(layerStack.id);
@@ -1271,12 +1262,12 @@ TEST_F(MultiDisplayTests, drop_input_for_secure_layer_on_nonsecure_display) {
 
     injectTapOnDisplay(101, 101, layerStack.id);
 
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 
     surface->requestFocus(layerStack.id);
     surface->assertFocusChange(true);
     injectKeyOnDisplay(AKEYCODE_V, layerStack.id);
-    EXPECT_EQ(surface->consumeEvent(100), nullptr);
+    EXPECT_EQ(surface->consumeEvent(/*timeout=*/100ms), nullptr);
 }
 
 TEST_F(MultiDisplayTests, dont_drop_input_for_secure_layer_on_secure_display) {
diff --git a/libs/input/InputTransport.cpp b/libs/input/InputTransport.cpp
index 598f949f8a..e63b8f012f 100644
--- a/libs/input/InputTransport.cpp
+++ b/libs/input/InputTransport.cpp
@@ -521,11 +521,11 @@ status_t InputChannel::receiveMessage(InputMessage* msg) {
 bool InputChannel::probablyHasInput() const {
     struct pollfd pfds = {.fd = mFd, .events = POLLIN};
     if (::poll(&pfds, /*nfds=*/1, /*timeout=*/0) <= 0) {
-        // This can be a false negative because EAGAIN and ENOMEM are not handled. The latter should
-        // be extremely rare. The EAGAIN is also unlikely because it happens only when the signal
-        // arrives while the syscall is executed, and the syscall is quick. Hitting EAGAIN too often
+        // This can be a false negative because EINTR and ENOMEM are not handled. The latter should
+        // be extremely rare. The EINTR is also unlikely because it happens only when the signal
+        // arrives while the syscall is executed, and the syscall is quick. Hitting EINTR too often
         // would be a sign of having too many signals, which is a bigger performance problem. A
-        // common tradition is to repeat the syscall on each EAGAIN, but it is not necessary here.
+        // common tradition is to repeat the syscall on each EINTR, but it is not necessary here.
         // In other words, the missing one liner is replaced by a multiline explanation.
         return false;
     }
@@ -534,6 +534,22 @@ bool InputChannel::probablyHasInput() const {
     return (pfds.revents & POLLIN) != 0;
 }
 
+void InputChannel::waitForMessage(std::chrono::milliseconds timeout) const {
+    if (timeout < 0ms) {
+        LOG(FATAL) << "Timeout cannot be negative, received " << timeout.count();
+    }
+    struct pollfd pfds = {.fd = mFd, .events = POLLIN};
+    int ret;
+    std::chrono::time_point<std::chrono::steady_clock> stopTime =
+            std::chrono::steady_clock::now() + timeout;
+    std::chrono::milliseconds remaining = timeout;
+    do {
+        ret = ::poll(&pfds, /*nfds=*/1, /*timeout=*/remaining.count());
+        remaining = std::chrono::duration_cast<std::chrono::milliseconds>(
+                stopTime - std::chrono::steady_clock::now());
+    } while (ret == -1 && errno == EINTR && remaining > 0ms);
+}
+
 std::unique_ptr<InputChannel> InputChannel::dup() const {
     base::unique_fd newFd(dupFd());
     return InputChannel::create(getName(), std::move(newFd), getConnectionToken());