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// Copyright (c) 2006-2008 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 "net/http/winhttp_request_throttle.h"
#include "base/logging.h"
#include "net/http/http_transaction_winhttp.h"
namespace {
// The arguments to a WinHttpSendRequest call.
struct SendRequestArgs {
SendRequestArgs() : request_handle(NULL), total_size(0), context(0) {}
SendRequestArgs(HINTERNET handle, DWORD size, DWORD_PTR context_value)
: request_handle(handle), total_size(size), context(context_value) {}
HINTERNET request_handle;
DWORD total_size;
DWORD_PTR context;
};
} // namespace
namespace net {
// Per-server queue for WinHttpSendRequest calls.
class WinHttpRequestThrottle::RequestQueue {
public:
RequestQueue() {}
// Adds |args| to the end of the queue.
void PushBack(const SendRequestArgs& args) { queue_.push_back(args); }
// If the queue is not empty, pops the first entry off the queue, saves it
// in |*args|, and returns true. If the queue is empty, returns false.
bool GetFront(SendRequestArgs* args);
// If the queue has an entry containing |request_handle|, removes it and
// returns true. Otherwise, returns false.
bool Remove(HINTERNET request_handle);
bool empty() const { return queue_.empty(); }
private:
std::list<SendRequestArgs> queue_;
DISALLOW_EVIL_CONSTRUCTORS(RequestQueue);
};
bool WinHttpRequestThrottle::RequestQueue::GetFront(SendRequestArgs* args) {
if (queue_.empty())
return false;
*args = queue_.front();
queue_.pop_front();
return true;
}
bool WinHttpRequestThrottle::RequestQueue::Remove(HINTERNET request_handle) {
std::list<SendRequestArgs>::iterator it;
for (it = queue_.begin(); it != queue_.end(); ++it) {
if (it->request_handle == request_handle) {
queue_.erase(it);
return true;
}
}
return false;
}
WinHttpRequestThrottle::~WinHttpRequestThrottle() {
#ifndef NDEBUG
ThrottleMap::const_iterator throttle_iter = throttles_.begin();
for (; throttle_iter != throttles_.end(); ++throttle_iter) {
const PerServerThrottle& throttle = throttle_iter->second;
DCHECK(throttle.num_requests == 0);
DCHECK(!throttle.request_queue.get() || throttle.request_queue->empty());
}
#endif
}
BOOL WinHttpRequestThrottle::SubmitRequest(const std::string &server,
HINTERNET request_handle,
DWORD total_size,
DWORD_PTR context) {
PerServerThrottle& throttle = throttles_[server];
DCHECK(throttle.num_requests >= 0 &&
throttle.num_requests <= kMaxConnectionsPerServer);
if (throttle.num_requests >= kMaxConnectionsPerServer) {
if (!throttle.request_queue.get())
throttle.request_queue.reset(new RequestQueue);
SendRequestArgs args(request_handle, total_size, context);
throttle.request_queue->PushBack(args);
return TRUE;
}
BOOL ok = SendRequest(request_handle, total_size, context, false);
if (ok)
throttle.num_requests += 1;
return ok;
}
void WinHttpRequestThrottle::NotifyRequestDone(const std::string& server) {
PerServerThrottle& throttle = throttles_[server];
DCHECK(throttle.num_requests > 0 &&
throttle.num_requests <= kMaxConnectionsPerServer);
throttle.num_requests -= 1;
SendRequestArgs args;
if (throttle.request_queue.get() &&
throttle.request_queue->GetFront(&args)) {
throttle.num_requests += 1;
SendRequest(args.request_handle, args.total_size, args.context, true);
}
if (throttles_.size() > static_cast<size_t>(kGarbageCollectionThreshold))
GarbageCollect();
}
void WinHttpRequestThrottle::RemoveRequest(const std::string& server,
HINTERNET request_handle) {
PerServerThrottle& throttle = throttles_[server];
if (throttle.request_queue.get() &&
throttle.request_queue->Remove(request_handle))
return;
NotifyRequestDone(server);
}
BOOL WinHttpRequestThrottle::SendRequest(HINTERNET request_handle,
DWORD total_size,
DWORD_PTR context,
bool report_async_error) {
BOOL ok = WinHttpSendRequest(request_handle,
WINHTTP_NO_ADDITIONAL_HEADERS,
0,
WINHTTP_NO_REQUEST_DATA,
0,
total_size,
context);
if (!ok && report_async_error) {
WINHTTP_ASYNC_RESULT async_result = { API_SEND_REQUEST, GetLastError() };
HttpTransactionWinHttp::StatusCallback(
request_handle, context,
WINHTTP_CALLBACK_STATUS_REQUEST_ERROR,
&async_result, sizeof(async_result));
}
return ok;
}
WinHttpRequestThrottle::PerServerThrottle::PerServerThrottle()
: num_requests(0) {
}
WinHttpRequestThrottle::PerServerThrottle::~PerServerThrottle() {
}
// static
const int WinHttpRequestThrottle::kMaxConnectionsPerServer = 6;
// static
const int WinHttpRequestThrottle::kGarbageCollectionThreshold = 64;
void WinHttpRequestThrottle::GarbageCollect() {
ThrottleMap::iterator throttle_iter = throttles_.begin();
while (throttle_iter != throttles_.end()) {
PerServerThrottle& throttle = throttle_iter->second;
if (throttle.num_requests == 0 &&
(!throttle.request_queue.get() || throttle.request_queue->empty())) {
// Erase the current item but keep the iterator valid.
throttles_.erase(throttle_iter++);
} else {
++throttle_iter;
}
}
}
} // namespace net
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