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SingularityViewer/indra/llmessage/aicurlperhost.h
2012-11-19 04:42:02 +01:00

136 lines
5.5 KiB
C++

/**
* @file aicurlperhost.h
* @brief Definition of class PerHostRequestQueue
*
* Copyright (c) 2012, Aleric Inglewood.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* There are special exceptions to the terms and conditions of the GPL as
* it is applied to this Source Code. View the full text of the exception
* in the file doc/FLOSS-exception.txt in this software distribution.
*
* CHANGELOG
* and additional copyright holders.
*
* 04/11/2012
* Initial version, written by Aleric Inglewood @ SL
*/
#ifndef AICURLPERHOST_H
#define AICURLPERHOST_H
#include "llerror.h" // llassert
#include <string>
#include <deque>
#include <map>
#include <boost/intrusive_ptr.hpp>
#include "aithreadsafe.h"
class AICurlEasyRequest;
namespace AICurlPrivate {
namespace curlthread { class MultiHandle; }
class PerHostRequestQueue;
class RefCountedThreadSafePerHostRequestQueue;
class ThreadSafeBufferedCurlEasyRequest;
// Forward declaration of BufferedCurlEasyRequestPtr (see aicurlprivate.h).
typedef boost::intrusive_ptr<ThreadSafeBufferedCurlEasyRequest> BufferedCurlEasyRequestPtr;
// PerHostRequestQueue objects are created by the curl thread and destructed by the main thread.
// We need locking.
typedef AIThreadSafeSimpleDC<PerHostRequestQueue> threadsafe_PerHostRequestQueue;
typedef AIAccessConst<PerHostRequestQueue> PerHostRequestQueue_crat;
typedef AIAccess<PerHostRequestQueue> PerHostRequestQueue_rat;
typedef AIAccess<PerHostRequestQueue> PerHostRequestQueue_wat;
// We can't put threadsafe_PerHostRequestQueue in a std::map because you can't copy a mutex.
// Therefore, use an intrusive pointer for the threadsafe type.
typedef boost::intrusive_ptr<RefCountedThreadSafePerHostRequestQueue> PerHostRequestQueuePtr;
//-----------------------------------------------------------------------------
// PerHostRequestQueue
// This class provides a static interface to create and maintain instances
// of PerHostRequestQueue objects, so that at any moment there is at most
// one instance per hostname. Those instances then are used to queue curl
// requests when the maximum number of connections for that host already
// have been reached.
class PerHostRequestQueue {
private:
typedef std::map<std::string, PerHostRequestQueuePtr> instance_map_type;
typedef AIThreadSafeSimpleDC<instance_map_type> threadsafe_instance_map_type;
typedef AIAccess<instance_map_type> instance_map_rat;
typedef AIAccess<instance_map_type> instance_map_wat;
static threadsafe_instance_map_type sInstanceMap; // Map of PerHostRequestQueue instances with the hostname as key.
friend class AIThreadSafeSimpleDC<PerHostRequestQueue>; //threadsafe_PerHostRequestQueue
PerHostRequestQueue(void) : mAdded(0) { }
public:
typedef instance_map_type::iterator iterator;
typedef instance_map_type::const_iterator const_iterator;
// Return (possibly create) a unique instance for the given hostname.
static PerHostRequestQueuePtr instance(std::string const& hostname);
// Release instance (object will be deleted if this was the last instance).
static void release(PerHostRequestQueuePtr& instance);
// Remove everything. Called upon viewer exit.
static void purge(void);
private:
typedef std::deque<BufferedCurlEasyRequestPtr> queued_request_type;
int mAdded; // Number of active easy handles with this host.
queued_request_type mQueuedRequests; // Waiting (throttled) requests.
public:
void added_to_multi_handle(void); // Called when an easy handle for this host has been added to the multi handle.
void removed_from_multi_handle(void); // Called when an easy handle for this host is removed again from the multi handle.
bool throttled(void) const; // Returns true if the maximum number of allowed requests for this host have been added to the multi handle.
void queue(AICurlEasyRequest const& easy_request); // Add easy_request to the queue.
bool cancel(AICurlEasyRequest const& easy_request); // Remove easy_request from the queue (if it's there).
void add_queued_to(curlthread::MultiHandle* mh); // Add queued easy handle (if any) to the multi handle. The request is removed from the queue,
// followed by either a call to added_to_multi_handle() or to queue() to add it back.
private:
// Disallow copying.
PerHostRequestQueue(PerHostRequestQueue const&) { }
};
class RefCountedThreadSafePerHostRequestQueue : public threadsafe_PerHostRequestQueue {
public:
RefCountedThreadSafePerHostRequestQueue(void) : mReferenceCount(0) { }
bool exactly_two_left(void) const { return mReferenceCount == 2; }
private:
// Used by PerHostRequestQueuePtr. Object is deleted when reference count reaches zero.
LLAtomicU32 mReferenceCount;
friend void intrusive_ptr_add_ref(RefCountedThreadSafePerHostRequestQueue* p);
friend void intrusive_ptr_release(RefCountedThreadSafePerHostRequestQueue* p);
};
extern U32 curl_concurrent_connections_per_host;
} // namespace AICurlPrivate
#endif // AICURLPERHOST_H