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#ifndef QPID_CLIENT_FLOWCONTROL_H
#define QPID_CLIENT_FLOWCONTROL_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/sys/IntegerTypes.h>
namespace qpid {
namespace client {
/**
* Flow control works by associating a finite amount of "credit"
* with a subscription.
*
* Credit includes a message count and a byte count. Each message
* received decreases the message count by one, and the byte count by
* the size of the message. Either count can have the special value
* UNLIMITED which is never decreased.
*
* A subscription's credit is exhausted when the message count is 0 or
* the byte count is too small for the next available message. The
* subscription will not receive any further messages until is credit
* is renewed.
*
* In "window mode" credit is automatically renewed when a message is
* completed (which by default happens when it is accepted). In
* non-window mode credit is not automatically renewed, it must be
* explicitly re-set (@see Subscription)
*/
struct FlowControl {
static const uint32_t UNLIMITED=0xFFFFFFFF;
FlowControl(uint32_t messages_=0, uint32_t bytes_=0, bool window_=false)
: messages(messages_), bytes(bytes_), window(window_) {}
static FlowControl messageCredit(uint32_t messages_) { return FlowControl(messages_,UNLIMITED,false); }
static FlowControl messageWindow(uint32_t messages_) { return FlowControl(messages_,UNLIMITED,true); }
static FlowControl byteCredit(uint32_t bytes_) { return FlowControl(UNLIMITED,bytes_,false); }
static FlowControl byteWindow(uint32_t bytes_) { return FlowControl(UNLIMITED,bytes_,true); }
static FlowControl unlimited() { return FlowControl(UNLIMITED, UNLIMITED, false); }
static FlowControl zero() { return FlowControl(0, 0, false); }
/** Message credit: subscription can accept up to this many messages. */
uint32_t messages;
/** Byte credit: subscription can accept up to this many bytes of message content. */
uint32_t bytes;
/** Window mode. If true credit is automatically renewed as messages are acknowledged. */
bool window;
bool operator==(const FlowControl& x) {
return messages == x.messages && bytes == x.bytes && window == x.window;
};
};
}} // namespace qpid::client
#endif /*!QPID_CLIENT_FLOWCONTROL_H*/
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