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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/webdata/common/web_data_request_manager.h"
#include <utility>
#include "base/functional/bind.h"
#include "base/location.h"
#include "base/memory/ptr_util.h"
#include "base/task/sequenced_task_runner.h"
#include "base/task/thread_pool.h"
////////////////////////////////////////////////////////////////////////////////
//
// WebDataRequest implementation.
//
////////////////////////////////////////////////////////////////////////////////
WebDataRequest::~WebDataRequest() {
WebDataRequestManager* manager = GetManager();
if (manager) {
manager->CancelRequest(handle_);
}
}
WebDataServiceBase::Handle WebDataRequest::GetHandle() const {
return handle_;
}
bool WebDataRequest::IsActive() {
return GetManager() != nullptr;
}
WebDataRequest::WebDataRequest(WebDataRequestManager* manager,
WebDataServiceRequestCallback consumer,
WebDataServiceBase::Handle handle)
: task_runner_(base::SequencedTaskRunner::HasCurrentDefault()
? base::SequencedTaskRunner::GetCurrentDefault()
: nullptr),
atomic_manager_(manager),
consumer_(std::move(consumer)),
handle_(handle) {
DCHECK(IsActive());
static_assert(sizeof(atomic_manager_) == sizeof(manager), "size mismatch");
}
WebDataRequestManager* WebDataRequest::GetManager() {
return atomic_manager_.load(std::memory_order_acquire);
}
WebDataServiceRequestCallback WebDataRequest::ExtractConsumer() && {
return std::move(consumer_);
}
scoped_refptr<base::SequencedTaskRunner> WebDataRequest::GetTaskRunner() {
return task_runner_;
}
void WebDataRequest::MarkAsInactive() {
atomic_manager_.store(nullptr, std::memory_order_release);
}
////////////////////////////////////////////////////////////////////////////////
//
// WebDataRequestManager implementation.
//
////////////////////////////////////////////////////////////////////////////////
WebDataRequestManager::WebDataRequestManager() : next_request_handle_(1) {}
std::unique_ptr<WebDataRequest> WebDataRequestManager::NewRequest(
WebDataServiceRequestCallback consumer) {
base::AutoLock l(pending_lock_);
std::unique_ptr<WebDataRequest> request = base::WrapUnique(
new WebDataRequest(this, std::move(consumer), next_request_handle_));
bool inserted =
pending_requests_.emplace(next_request_handle_, request.get()).second;
DCHECK(inserted);
++next_request_handle_;
return request;
}
void WebDataRequestManager::CancelRequest(WebDataServiceBase::Handle h) {
base::AutoLock l(pending_lock_);
// If the request was already cancelled, or has already completed, it won't
// be in the pending_requests_ collection any more.
auto i = pending_requests_.find(h);
if (i == pending_requests_.end()) {
return;
}
i->second->MarkAsInactive();
pending_requests_.erase(i);
}
void WebDataRequestManager::RequestCompleted(
std::unique_ptr<WebDataRequest> request,
std::unique_ptr<WDTypedResult> result) {
// Careful: Don't swap this below the BindOnce() call below, since that
// effectively does a std::move() on |request|!
scoped_refptr<base::SequencedTaskRunner> task_runner =
request->GetTaskRunner();
auto task = base::BindOnce(&WebDataRequestManager::RequestCompletedOnThread,
this, std::move(request), std::move(result));
if (task_runner) {
task_runner->PostTask(FROM_HERE, std::move(task));
} else {
base::ThreadPool::PostTask(FROM_HERE, std::move(task));
}
}
WebDataRequestManager::~WebDataRequestManager() {
base::AutoLock l(pending_lock_);
for (auto& pending_request : pending_requests_) {
pending_request.second->MarkAsInactive();
}
pending_requests_.clear();
}
void WebDataRequestManager::RequestCompletedOnThread(
std::unique_ptr<WebDataRequest> request,
std::unique_ptr<WDTypedResult> result) {
// Check whether the request is active. It might have been cancelled in
// another thread before this completion handler was invoked. This means the
// request initiator is no longer interested in the result.
if (!request->IsActive()) {
return;
}
WebDataServiceBase::Handle handle = request->GetHandle();
WebDataServiceRequestCallback consumer =
std::move(*request).ExtractConsumer();
// Stop tracking the request. The request is already finished, so "stop
// tracking" is the same as post-facto cancellation.
CancelRequest(handle);
// Notify the consumer if needed.
if (!consumer.is_null()) {
std::move(consumer).Run(handle, std::move(result));
}
}
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