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/*
* Copyright 2023 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "api/environment/environment_factory.h"
#include <memory>
#include <utility>
#include "absl/base/nullability.h"
#include "api/environment/environment.h"
#include "api/field_trials_view.h"
#include "api/make_ref_counted.h"
#include "api/ref_counted_base.h"
#include "api/rtc_event_log/rtc_event_log.h"
#include "api/scoped_refptr.h"
#include "api/task_queue/default_task_queue_factory.h"
#include "api/task_queue/task_queue_factory.h"
#include "api/transport/field_trial_based_config.h"
#include "rtc_base/checks.h"
#include "system_wrappers/include/clock.h"
namespace webrtc {
namespace {
template <typename T>
void Store(absl::Nonnull<std::unique_ptr<T>> value,
scoped_refptr<const rtc::RefCountedBase>& leaf) {
class StorageNode : public rtc::RefCountedBase {
public:
StorageNode(scoped_refptr<const rtc::RefCountedBase> parent,
absl::Nonnull<std::unique_ptr<T>> value)
: parent_(std::move(parent)), value_(std::move(value)) {}
StorageNode(const StorageNode&) = delete;
StorageNode& operator=(const StorageNode&) = delete;
~StorageNode() override = default;
private:
scoped_refptr<const rtc::RefCountedBase> parent_;
absl::Nonnull<std::unique_ptr<T>> value_;
};
// Utilities provided with ownership form a tree:
// Root is nullptr, each node keeps an ownership of one utility.
// Each child node has a link to the parent, but parent is unaware of its
// children. Each `EnvironmentFactory` and `Environment` keep a reference to a
// 'leaf_' - node with the last provided utility. This way `Environment` keeps
// ownership of a single branch of the storage tree with each used utiltity
// owned by one of the nodes on that branch.
leaf = rtc::make_ref_counted<StorageNode>(std::move(leaf), std::move(value));
}
} // namespace
EnvironmentFactory::EnvironmentFactory(const Environment& env)
: leaf_(env.storage_),
field_trials_(env.field_trials_),
clock_(env.clock_),
task_queue_factory_(env.task_queue_factory_),
event_log_(env.event_log_) {}
void EnvironmentFactory::Set(
absl::Nullable<std::unique_ptr<const FieldTrialsView>> utility) {
if (utility != nullptr) {
field_trials_ = utility.get();
Store(std::move(utility), leaf_);
}
}
void EnvironmentFactory::Set(absl::Nullable<std::unique_ptr<Clock>> utility) {
if (utility != nullptr) {
clock_ = utility.get();
Store(std::move(utility), leaf_);
}
}
void EnvironmentFactory::Set(
absl::Nullable<std::unique_ptr<TaskQueueFactory>> utility) {
if (utility != nullptr) {
task_queue_factory_ = utility.get();
Store(std::move(utility), leaf_);
}
}
void EnvironmentFactory::Set(
absl::Nullable<std::unique_ptr<RtcEventLog>> utility) {
if (utility != nullptr) {
event_log_ = utility.get();
Store(std::move(utility), leaf_);
}
}
Environment EnvironmentFactory::CreateWithDefaults() && {
if (field_trials_ == nullptr) {
Set(std::make_unique<FieldTrialBasedConfig>());
}
#if defined(WEBRTC_MOZILLA_BUILD)
// We want to use our clock, not GetRealTimeClockRaw, and we avoid
// building the code under third_party/libwebrtc/task_queue. To
// ensure we're setting up things correctly, namely providing an
// Environment object with a preset task_queue_factory and clock,
// we'll do a release assert here.
RTC_CHECK(clock_);
RTC_CHECK(task_queue_factory_);
#else
if (clock_ == nullptr) {
Set(Clock::GetRealTimeClock());
}
if (task_queue_factory_ == nullptr) {
Set(CreateDefaultTaskQueueFactory(field_trials_));
}
#endif
if (event_log_ == nullptr) {
Set(std::make_unique<RtcEventLogNull>());
}
RTC_DCHECK(field_trials_ != nullptr);
RTC_DCHECK(clock_ != nullptr);
RTC_DCHECK(task_queue_factory_ != nullptr);
RTC_DCHECK(event_log_ != nullptr);
return Environment(std::move(leaf_), //
field_trials_, clock_, task_queue_factory_, event_log_);
}
Environment EnvironmentFactory::Create() const {
// Create a temporary copy to avoid mutating `this` with default utilities.
return EnvironmentFactory(*this).CreateWithDefaults();
}
} // namespace webrtc