Add displayservice.

This hidl service provides information about vsync and hotplug
to vendor services which is required by at least some camera
hal implementations.

Test: VtsFwkDisplayServiceV1_0TargetTest
Bug: 38311538
Change-Id: Ifc344c11ca4b3c8cebc6f0145f506d1aa774506d
diff --git a/services/displayservice/DisplayEventReceiver.cpp b/services/displayservice/DisplayEventReceiver.cpp
new file mode 100644
index 0000000..a7fd3c5
--- /dev/null
+++ b/services/displayservice/DisplayEventReceiver.cpp
@@ -0,0 +1,167 @@
+/*
+ * Copyright (C) 2017 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.
+ */
+#define LOG_TAG "libdisplayservicehidl"
+
+#include <displayservice/DisplayEventReceiver.h>
+
+#include <android-base/logging.h>
+#include <android/frameworks/displayservice/1.0/BpHwEventCallback.h>
+
+#include <thread>
+
+namespace android {
+namespace frameworks {
+namespace displayservice {
+namespace V1_0 {
+namespace implementation {
+
+sp<Looper> getLooper() {
+    static sp<Looper> looper = []() {
+        sp<Looper> looper = new Looper(false /* allowNonCallbacks */);
+
+        std::thread{[&](){
+            int pollResult = looper->pollAll(-1 /* timeout */);
+            LOG(ERROR) << "Looper::pollAll returns unexpected " << pollResult;
+        }}.detach();
+
+        return looper;
+    }();
+
+    return looper;
+}
+
+DisplayEventReceiver::AttachedEvent::AttachedEvent(const sp<IEventCallback> &callback) : mCallback(callback) {
+    mLooperAttached = getLooper()->addFd(mFwkReceiver.getFd(),
+                                         Looper::POLL_CALLBACK,
+                                         Looper::EVENT_INPUT,
+                                         this,
+                                         nullptr);
+}
+
+DisplayEventReceiver::AttachedEvent::~AttachedEvent() {
+    if (!detach()) {
+        LOG(ERROR) << "Could not remove fd from looper.";
+    }
+}
+
+bool DisplayEventReceiver::AttachedEvent::detach() {
+    if (!valid()) {
+        return true;
+    }
+
+    return getLooper()->removeFd(mFwkReceiver.getFd());
+}
+
+bool DisplayEventReceiver::AttachedEvent::valid() const {
+    return mFwkReceiver.initCheck() == OK && mLooperAttached;
+}
+
+DisplayEventReceiver::FwkReceiver &DisplayEventReceiver::AttachedEvent::receiver() {
+    return mFwkReceiver;
+}
+
+int DisplayEventReceiver::AttachedEvent::handleEvent(int fd, int events, void* /* data */) {
+    CHECK(fd == mFwkReceiver.getFd());
+
+    if (events & (Looper::EVENT_ERROR | Looper::EVENT_HANGUP)) {
+        LOG(ERROR) << "AttachedEvent handleEvent received error or hangup:" << events;
+        return 0; // remove the callback
+    }
+
+    if (!(events & Looper::EVENT_INPUT)) {
+        LOG(ERROR) << "AttachedEvent handleEvent unhandled poll event:" << events;
+        return 1; // keep the callback
+    }
+
+    const static size_t SIZE = 1;
+
+    ssize_t n;
+    FwkReceiver::Event buf[SIZE];
+    while ((n = mFwkReceiver.getEvents(buf, SIZE)) > 0) {
+        for (size_t i = 0; i < static_cast<size_t>(n); ++i) {
+            const FwkReceiver::Event &event = buf[i];
+
+            uint32_t type = event.header.type;
+            uint64_t timestamp = event.header.timestamp;
+
+            switch(buf[i].header.type) {
+                case FwkReceiver::DISPLAY_EVENT_VSYNC: {
+                    mCallback->onVsync(timestamp, event.vsync.count);
+                } break;
+                case FwkReceiver::DISPLAY_EVENT_HOTPLUG: {
+                    mCallback->onHotplug(timestamp, event.hotplug.connected);
+                } break;
+                default: {
+                    LOG(ERROR) << "AttachedEvent handleEvent unknown type: " << type;
+                }
+            }
+        }
+    }
+
+    return 1; // keep on going
+}
+
+Return<Status> DisplayEventReceiver::init(const sp<IEventCallback>& callback) {
+    std::unique_lock<std::mutex> lock(mMutex);
+
+    if (mAttached != nullptr || callback == nullptr) {
+        return Status::BAD_VALUE;
+    }
+
+    mAttached = new AttachedEvent(callback);
+
+    return mAttached->valid() ? Status::SUCCESS : Status::UNKNOWN;
+}
+
+Return<Status> DisplayEventReceiver::setVsyncRate(int32_t count) {
+    std::unique_lock<std::mutex> lock(mMutex);
+
+    if (mAttached == nullptr || count < 0) {
+        return Status::BAD_VALUE;
+    }
+
+    bool success = OK == mAttached->receiver().setVsyncRate(count);
+    return success ? Status::SUCCESS : Status::UNKNOWN;
+}
+
+Return<Status> DisplayEventReceiver::requestNextVsync() {
+    std::unique_lock<std::mutex> lock(mMutex);
+
+    if (mAttached == nullptr) {
+        return Status::BAD_VALUE;
+    }
+
+    bool success = OK == mAttached->receiver().requestNextVsync();
+    return success ? Status::SUCCESS : Status::UNKNOWN;
+}
+
+Return<Status> DisplayEventReceiver::close() {
+    if (mAttached == nullptr) {
+        return Status::BAD_VALUE;
+    }
+
+    std::unique_lock<std::mutex> lock(mMutex);
+    bool success = mAttached->detach();
+    mAttached = nullptr;
+
+    return success ? Status::SUCCESS : Status::UNKNOWN;
+}
+
+}  // namespace implementation
+}  // namespace V1_0
+}  // namespace displayservice
+}  // namespace frameworks
+}  // namespace android