Migrate reference external HAL implementation to AIDL
Android T migrated the HAL interface to AIDL, but the reference HAL
was never updated to use AIDL. This CL migrates the reference
HAL implementation for external cameras to use AIDL as well. The
external HAL uses V4L2 standard to expose USB cameras to the
cameraserver.
The reference HAL implementation for internal camera was dropped
because it is not possible to write a generic HAL that works with some
large percentage of internal cameras.
Bug: 219974678
Test: Existing CTS tests pass with external camera connected.
Change-Id: I35f3dc32c16670eca7735a4ac00fed3daf36aa65
diff --git a/camera/common/1.0/default/Android.bp b/camera/common/1.0/default/Android.bp
index 4a5ca83..1a4d16b 100644
--- a/camera/common/1.0/default/Android.bp
+++ b/camera/common/1.0/default/Android.bp
@@ -18,6 +18,7 @@
"VendorTagDescriptor.cpp",
"HandleImporter.cpp",
"Exif.cpp",
+ "SimpleThread.cpp",
],
cflags: [
"-Werror",
diff --git a/camera/common/1.0/default/SimpleThread.cpp b/camera/common/1.0/default/SimpleThread.cpp
new file mode 100644
index 0000000..46e89ba
--- /dev/null
+++ b/camera/common/1.0/default/SimpleThread.cpp
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2022 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 "SimpleThread.h"
+
+namespace android {
+namespace hardware {
+namespace camera {
+namespace common {
+namespace helper {
+
+SimpleThread::SimpleThread() : mDone(true), mThread() {}
+SimpleThread::~SimpleThread() {
+ // Safe to call requestExitAndWait() from the destructor because requestExitAndWait() ensures
+ // that the thread is joinable before joining on it. This is different from how
+ // android::Thread worked.
+ requestExitAndWait();
+}
+
+void SimpleThread::run() {
+ requestExitAndWait(); // Exit current execution, if any.
+
+ // start thread
+ mDone.store(false, std::memory_order_release);
+ mThread = std::thread(&SimpleThread::runLoop, this);
+}
+
+void SimpleThread::requestExitAndWait() {
+ // Signal thread to stop
+ mDone.store(true, std::memory_order_release);
+
+ // Wait for thread to exit if needed. This should happen in no more than one iteration of
+ // threadLoop
+ if (mThread.joinable()) {
+ mThread.join();
+ }
+ mThread = std::thread();
+}
+
+void SimpleThread::runLoop() {
+ while (!exitPending()) {
+ if (!threadLoop()) {
+ break;
+ }
+ }
+}
+
+} // namespace helper
+} // namespace common
+} // namespace camera
+} // namespace hardware
+} // namespace android
\ No newline at end of file
diff --git a/camera/common/1.0/default/include/SimpleThread.h b/camera/common/1.0/default/include/SimpleThread.h
new file mode 100644
index 0000000..d1becd6
--- /dev/null
+++ b/camera/common/1.0/default/include/SimpleThread.h
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2022 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 HARDWARE_INTERFACES_CAMERA_COMMON_SIMPLETHREAD_H_
+#define HARDWARE_INTERFACES_CAMERA_COMMON_SIMPLETHREAD_H_
+
+#include <thread>
+
+namespace android {
+namespace hardware {
+namespace camera {
+namespace common {
+namespace helper {
+
+// A simple looper based on std::thread.
+class SimpleThread {
+ public:
+ SimpleThread();
+ virtual ~SimpleThread();
+
+ // Explicit call to start execution of the thread. No thread is created before this function
+ // is called.
+ virtual void run() final;
+ virtual void requestExitAndWait() final;
+
+ protected:
+ // Main logic of the thread. This function is called repeatedly until it returns false.
+ // Thread execution stops if this function returns false.
+ virtual bool threadLoop() = 0;
+
+ // Returns true if the thread execution should stop. Should be used by threadLoop to check if
+ // the thread has been requested to exit.
+ virtual inline bool exitPending() final { return mDone.load(std::memory_order_acquire); }
+
+ private:
+ // Wraps threadLoop in a simple while loop that allows safe exit
+ virtual void runLoop() final;
+
+ // Flag to signal end of thread execution. This flag is checked before every iteration
+ // of threadLoop.
+ std::atomic_bool mDone;
+ std::thread mThread;
+};
+
+} // namespace helper
+} // namespace common
+} // namespace camera
+} // namespace hardware
+} // namespace android
+
+#endif // HARDWARE_INTERFACES_CAMERA_COMMON_SIMPLETHREAD_H_