1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
|
#ifndef QPID_CLUSTER_POLLABLEQUEUE_H
#define QPID_CLUSTER_POLLABLEQUEUE_H
/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 "qpid/cluster/PollableCondition.h"
#include "qpid/sys/Dispatcher.h"
#include "qpid/sys/Mutex.h"
#include <boost/function.hpp>
#include <boost/bind.hpp>
#include <deque>
namespace qpid {
namespace sys { class Poller; }
namespace cluster {
// FIXME aconway 2008-08-11: this could be of more general interest,
// move to common lib.
/**
* A queue that can be polled by sys::Poller. Any thread can push to
* the queue, on wakeup the poller thread processes all items on the
* queue by passing them to a callback in a batch.
*/
template <class T>
class PollableQueue {
typedef std::deque<T> Queue;
public:
typedef typename Queue::iterator iterator;
/** Callback to process a range of items. */
typedef boost::function<void (const iterator&, const iterator&)> Callback;
/** When the queue is selected by the poller, values are passed to callback cb. */
explicit PollableQueue(const Callback& cb);
/** Push a value onto the queue. Thread safe */
void push(const T& t) { ScopedLock l(lock); queue.push_back(t); condition.set(); }
/** Start polling. */
void start(const boost::shared_ptr<sys::Poller>& poller) { handle.startWatch(poller); }
/** Stop polling. */
void stop() { handle.stopWatch(); }
private:
typedef sys::Mutex::ScopedLock ScopedLock;
typedef sys::Mutex::ScopedUnlock ScopedUnlock;
void dispatch(sys::DispatchHandle&);
sys::Mutex lock;
Callback callback;
PollableCondition condition;
sys::DispatchHandle handle;
Queue queue;
Queue batch;
};
template <class T> PollableQueue<T>::PollableQueue(const Callback& cb) // FIXME aconway 2008-08-12:
: callback(cb),
handle(condition, boost::bind(&PollableQueue<T>::dispatch, this, _1), 0, 0)
{}
template <class T> void PollableQueue<T>::dispatch(sys::DispatchHandle& h) {
ScopedLock l(lock); // Lock for concurrent push()
batch.clear();
batch.swap(queue);
condition.clear();
ScopedUnlock u(lock);
callback(batch.begin(), batch.end()); // Process the batch outside the lock.
h.rewatch();
}
}} // namespace qpid::cluster
#endif /*!QPID_CLUSTER_POLLABLEQUEUE_H*/
|
