blob: 82847c83026b25551ab51cc843c2554c2b448e57 [file] [log] [blame]
// Copyright 2019 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <memory>
#include <utility>
#include "base/callback_forward.h"
#include "base/macros.h"
#include "base/memory/scoped_refptr.h"
#include "base/memory/weak_ptr.h"
#include "base/single_thread_task_runner.h"
#include "third_party/grpc/src/include/grpcpp/client_context.h"
#include "third_party/grpc/src/include/grpcpp/support/status.h"
namespace grpc {
class CompletionQueue;
} // namespace grpc
namespace remoting {
// The GrpcAsyncRequest base class that holds logic invariant to the response
// type.
// The lifetime of GrpcAsyncRequest is bound to the completion queue. A
// subclass may enqueue itself multiple times into the completion queue, and
// GrpcAsyncExecutor will dequeue it and call OnDequeue() when the event is
// handled. If the subclass won't re-enqueue itself, OnDequeue() should return
// false, which will delete the request object.
// All methods are called from the same sequence, but the destructor could end
// up being called on an arbitrary sequence if the caller's sequence itself has
// been destroyed.
class GrpcAsyncRequest {
using RunTaskCallback = base::RepeatingCallback<void(base::OnceClosure)>;
virtual ~GrpcAsyncRequest();
grpc::ClientContext* context() { return &context_; }
// Methods below are considered internal to grpc_support.
// Force dequeues any pending request.
void CancelRequest();
// Starts the request. Subclass can store |cq| but should only use |event_tag|
// before the method returns.
// Subclass shall only run callbacks using |run_task_cb|. Directly running
// task in OnDequeue() might result in concurrency issue.
virtual void Start(const RunTaskCallback& run_task_cb,
grpc::CompletionQueue* cq,
void* event_tag) = 0;
// Called when the request has been dequeued from the completion queue.
// Returns true iff the task is not finished, and Reenqueue() should be
// called.
virtual bool OnDequeue(bool operation_succeeded) = 0;
// Re-enqueues the request. This is only called if the previous call to
// OnDequeue() returns true. Subclass shall not store |event_tag|.
virtual void Reenqueue(void* event_tag) = 0;
// Called before calling Start(). If this returns false then Start() won't be
// called and request will be silently dropped.
virtual bool CanStartRequest() const = 0;
base::WeakPtr<GrpcAsyncRequest> GetGrpcAsyncRequestWeakPtr();
// Called after CancelRequest() is called.
virtual void OnRequestCanceled() = 0;
grpc::Status status_{grpc::StatusCode::UNKNOWN, "Uninitialized"};
grpc::ClientContext context_;
base::WeakPtrFactory<GrpcAsyncRequest> grpc_async_request_weak_factory_;
} // namespace remoting