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/*
* Copyright 2018 Google
*
* 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 "Firestore/core/src/firebase/firestore/util/async_queue.h"
#include <utility>
#include "Firestore/core/src/firebase/firestore/util/firebase_assert.h"
#include "absl/memory/memory.h"
namespace firebase {
namespace firestore {
namespace util {
using internal::Executor;
AsyncQueue::AsyncQueue(std::unique_ptr<Executor> executor)
: executor_{std::move(executor)} {
is_operation_in_progress_ = false;
}
void AsyncQueue::VerifyIsCurrentExecutor() const {
FIREBASE_ASSERT_MESSAGE(
executor_->IsCurrentExecutor(),
"Expected to be called by the executor associated with this queue "
"(expected executor: '%s', actual executor: '%s')",
executor_->Name().c_str(), executor_->CurrentExecutorName().c_str());
}
void AsyncQueue::VerifyIsCurrentQueue() const {
VerifyIsCurrentExecutor();
FIREBASE_ASSERT_MESSAGE(
is_operation_in_progress_,
"VerifyIsCurrentQueue called when no operation is executing "
"(expected executor: '%s', actual executor: '%s')",
executor_->Name().c_str(), executor_->CurrentExecutorName().c_str());
}
void AsyncQueue::ExecuteBlocking(const Operation& operation) {
VerifyIsCurrentExecutor();
FIREBASE_ASSERT_MESSAGE(!is_operation_in_progress_,
"ExecuteBlocking may not be called "
"before the previous operation finishes executing");
is_operation_in_progress_ = true;
operation();
is_operation_in_progress_ = false;
}
void AsyncQueue::Enqueue(const Operation& operation) {
VerifySequentialOrder();
EnqueueRelaxed(operation);
}
void AsyncQueue::EnqueueRelaxed(const Operation& operation) {
executor_->Execute(Wrap(operation));
}
DelayedOperation AsyncQueue::EnqueueAfterDelay(const Milliseconds delay,
const TimerId timer_id,
const Operation& operation) {
VerifyIsCurrentExecutor();
// While not necessarily harmful, we currently don't expect to have multiple
// callbacks with the same timer_id in the queue, so defensively reject
// them.
FIREBASE_ASSERT_MESSAGE(
!IsScheduled(timer_id),
"Attempted to schedule multiple operations with id %d", timer_id);
Executor::TaggedOperation tagged{static_cast<int>(timer_id), Wrap(operation)};
return executor_->Schedule(delay, std::move(tagged));
}
AsyncQueue::Operation AsyncQueue::Wrap(const Operation& operation) {
// Decorator pattern: wrap `operation` into a call to `ExecuteBlocking` to
// ensure that it doesn't spawn any nested operations.
// Note: can't move `operation` into lambda until C++14.
return [this, operation] { ExecuteBlocking(operation); };
}
void AsyncQueue::VerifySequentialOrder() const {
// This is the inverse of `VerifyIsCurrentQueue`.
FIREBASE_ASSERT_MESSAGE(
!is_operation_in_progress_ || !executor_->IsCurrentExecutor(),
"Enforcing sequential order failed: currently executing operations "
"cannot enqueue more operations "
"(this queue's executor: '%s', current executor: '%s')",
executor_->Name().c_str(), executor_->CurrentExecutorName().c_str());
}
// Test-only functions
void AsyncQueue::EnqueueBlocking(const Operation& operation) {
VerifySequentialOrder();
executor_->ExecuteBlocking(Wrap(operation));
}
bool AsyncQueue::IsScheduled(const TimerId timer_id) const {
return executor_->IsScheduled(static_cast<int>(timer_id));
}
void AsyncQueue::RunScheduledOperationsUntil(const TimerId last_timer_id) {
FIREBASE_ASSERT_MESSAGE(
!executor_->IsCurrentExecutor(),
"RunScheduledOperationsUntil must not be called on the queue");
executor_->ExecuteBlocking([this, last_timer_id] {
FIREBASE_ASSERT_MESSAGE(
last_timer_id == TimerId::All || IsScheduled(last_timer_id),
"Attempted to run scheduled operations until missing timer id: %d",
last_timer_id);
for (auto next = executor_->PopFromSchedule(); next.has_value();
next = executor_->PopFromSchedule()) {
next->operation();
if (next->tag == static_cast<int>(last_timer_id)) {
break;
}
}
});
}
} // namespace util
} // namespace firestore
} // namespace firebase
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