NNAPI HAL: Change IEvent to explicit callbacks
IEvent was a synchronization primitive which caused some confusion
in the interface. Originally the event object was paired with an
asynchronous task, and the asynchronous task would signal this event
when the corresponding output was ready to be used.
In the case of IDevice::prepareModel, the function call would return an
IPreparedModel object that was not guaranteed to be prepared until the
runtime had returned from waiting on the corresponding event object.
The event object has been changed to two explicit callbacks--
IPreparedModelCallback and IExecutionCallback. Now,
IDevice::prepareModel no longer returns an unfinished IPreparedModel;
instead, it will pass the IPreparedModel object to the runtime through
IPreparedModelCallback::notify. When the runtime retreives the
IPreparedModel object, the asynchronous task has already finished
preparing the model.
The two callbacks are used for different purposes. Each has its own
version of notify to pass the data back to the runtime:
* IPreparedModelCallback::notify(ErrorStatus, IPreparedModel)
* IExecutionCallback::notify(ErrorStatus)
Bug: 63905942
Test: mm, vts, ml/nn/runtime/tests
Change-Id: I0c88cd262ba762e0af15e9da31ebe813a5d150b2
diff --git a/neuralnetworks/1.0/vts/functional/Callbacks.cpp b/neuralnetworks/1.0/vts/functional/Callbacks.cpp
new file mode 100644
index 0000000..46bf243
--- /dev/null
+++ b/neuralnetworks/1.0/vts/functional/Callbacks.cpp
@@ -0,0 +1,127 @@
+#include "Callbacks.h"
+#include <android-base/logging.h>
+
+namespace android {
+namespace hardware {
+namespace neuralnetworks {
+namespace V1_0 {
+namespace implementation {
+
+CallbackBase::CallbackBase() : mNotified(false) {}
+
+CallbackBase::~CallbackBase() {
+ // Note that we cannot call CallbackBase::join_thread from here:
+ // CallbackBase is intended to be reference counted, and it is possible that
+ // the reference count drops to zero in the bound thread, causing the
+ // bound thread to call this destructor. If a thread tries to join
+ // itself, it throws an exception, producing a message like the
+ // following:
+ //
+ // terminating with uncaught exception of type std::__1::system_error:
+ // thread::join failed: Resource deadlock would occur
+}
+
+void CallbackBase::wait() {
+ std::unique_lock<std::mutex> lock(mMutex);
+ mCondition.wait(lock, [this]{return mNotified;});
+ join_thread_locked();
+}
+
+bool CallbackBase::on_finish(std::function<bool(void)> post_work) {
+ std::lock_guard<std::mutex> lock(mMutex);
+ if (mPostWork != nullptr) {
+ LOG(ERROR) << "CallbackBase::on_finish -- a post-work function has already been bound to "
+ "this callback object";
+ return false;
+ }
+ if (post_work == nullptr) {
+ LOG(ERROR) << "CallbackBase::on_finish -- the new post-work function is invalid";
+ return false;
+ }
+ mPostWork = std::move(post_work);
+ return true;
+}
+
+bool CallbackBase::bind_thread(std::thread&& asyncThread) {
+ std::lock_guard<std::mutex> lock(mMutex);
+ if (mThread.joinable()) {
+ LOG(ERROR) << "CallbackBase::bind_thread -- a thread has already been bound to this "
+ "callback object";
+ return false;
+ }
+ if (!asyncThread.joinable()) {
+ LOG(ERROR) << "CallbackBase::bind_thread -- the new thread is not joinable";
+ return false;
+ }
+ mThread = std::move(asyncThread);
+ return true;
+}
+
+void CallbackBase::join_thread() {
+ std::lock_guard<std::mutex> lock(mMutex);
+ join_thread_locked();
+}
+
+void CallbackBase::notify() {
+ {
+ std::lock_guard<std::mutex> lock(mMutex);
+ mNotified = true;
+ if (mPostWork != nullptr) {
+ bool success = mPostWork();
+ if (!success) {
+ LOG(ERROR) << "CallbackBase::notify -- post work failed";
+ }
+ }
+ }
+ mCondition.notify_all();
+}
+
+void CallbackBase::join_thread_locked() {
+ if (mThread.joinable()) {
+ mThread.join();
+ }
+}
+
+PreparedModelCallback::PreparedModelCallback() :
+ mErrorStatus(ErrorStatus::GENERAL_FAILURE), mPreparedModel(nullptr) {}
+
+PreparedModelCallback::~PreparedModelCallback() {}
+
+Return<void> PreparedModelCallback::notify(ErrorStatus errorStatus,
+ const sp<IPreparedModel>& preparedModel) {
+ mErrorStatus = errorStatus;
+ mPreparedModel = preparedModel;
+ CallbackBase::notify();
+ return Void();
+}
+
+ErrorStatus PreparedModelCallback::getStatus() {
+ wait();
+ return mErrorStatus;
+}
+
+sp<IPreparedModel> PreparedModelCallback::getPreparedModel() {
+ wait();
+ return mPreparedModel;
+}
+
+ExecutionCallback::ExecutionCallback() : mErrorStatus(ErrorStatus::GENERAL_FAILURE) {}
+
+ExecutionCallback::~ExecutionCallback() {}
+
+Return<void> ExecutionCallback::notify(ErrorStatus errorStatus) {
+ mErrorStatus = errorStatus;
+ CallbackBase::notify();
+ return Void();
+}
+
+ErrorStatus ExecutionCallback::getStatus() {
+ wait();
+ return mErrorStatus;
+}
+
+} // namespace implementation
+} // namespace V1_0
+} // namespace neuralnetworks
+} // namespace hardware
+} // namespace android