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/*
*
* 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 <TopicExchange.h>
#include <ExchangeBinding.h>
#include <algorithm>
using namespace qpid::broker;
using namespace qpid::framing;
using namespace qpid::sys;
// TODO aconway 2006-09-20: More efficient matching algorithm.
// Areas for improvement:
// - excessive string copying: should be 0 copy, match from original buffer.
// - match/lookup: use descision tree or other more efficient structure.
Tokens& Tokens::operator=(const std::string& s) {
clear();
if (s.empty()) return *this;
std::string::const_iterator i = s.begin();
while (true) {
// Invariant: i is at the beginning of the next untokenized word.
std::string::const_iterator j = find(i, s.end(), '.');
push_back(std::string(i, j));
if (j == s.end()) return *this;
i = j + 1;
}
return *this;
}
TopicPattern& TopicPattern::operator=(const Tokens& tokens) {
Tokens::operator=(tokens);
normalize();
return *this;
}
namespace {
const std::string hashmark("#");
const std::string star("*");
}
void TopicPattern::normalize() {
std::string word;
Tokens::iterator i = begin();
while (i != end()) {
if (*i == hashmark) {
++i;
while (i != end()) {
// Invariant: *(i-1)==#, [begin()..i-1] is normalized.
if (*i == star) { // Move * before #.
std::swap(*i, *(i-1));
++i;
} else if (*i == hashmark) {
erase(i); // Remove extra #
} else {
break;
}
}
} else {
i ++;
}
}
}
namespace {
// TODO aconway 2006-09-20: Ineficient to convert every routingKey to a string.
// Need StringRef class that operates on a string in place witout copy.
// Should be applied everywhere strings are extracted from frames.
//
bool do_match(Tokens::const_iterator pattern_begin, Tokens::const_iterator pattern_end, Tokens::const_iterator target_begin, Tokens::const_iterator target_end)
{
// Invariant: [pattern_begin..p) matches [target_begin..t)
Tokens::const_iterator p = pattern_begin;
Tokens::const_iterator t = target_begin;
while (p != pattern_end && t != target_end)
{
if (*p == star || *p == *t) {
++p, ++t;
} else if (*p == hashmark) {
++p;
if (do_match(p, pattern_end, t, target_end)) return true;
while (t != target_end) {
++t;
if (do_match(p, pattern_end, t, target_end)) return true;
}
return false;
} else {
return false;
}
}
while (p != pattern_end && *p == hashmark) ++p; // Ignore trailing #
return t == target_end && p == pattern_end;
}
}
bool TopicPattern::match(const Tokens& target) const
{
return do_match(begin(), end(), target.begin(), target.end());
}
TopicExchange::TopicExchange(const string& _name) : Exchange(_name) { }
void TopicExchange::bind(Queue::shared_ptr queue, const string& routingKey, const FieldTable* args){
Monitor::ScopedLock l(lock);
TopicPattern routingPattern(routingKey);
bindings[routingPattern].push_back(queue);
queue->bound(new ExchangeBinding(this, queue, routingKey, args));
}
void TopicExchange::unbind(Queue::shared_ptr queue, const string& routingKey, const FieldTable* /*args*/){
Monitor::ScopedLock l(lock);
BindingMap::iterator bi = bindings.find(TopicPattern(routingKey));
Queue::vector& qv(bi->second);
if (bi == bindings.end()) return;
Queue::vector::iterator q = find(qv.begin(), qv.end(), queue);
if(q == qv.end()) return;
qv.erase(q);
if(qv.empty()) bindings.erase(bi);
}
void TopicExchange::route(Deliverable& msg, const string& routingKey, const FieldTable* /*args*/){
Monitor::ScopedLock l(lock);
for (BindingMap::iterator i = bindings.begin(); i != bindings.end(); ++i) {
if (i->first.match(routingKey)) {
Queue::vector& qv(i->second);
for(Queue::vector::iterator j = qv.begin(); j != qv.end(); j++){
msg.deliverTo(*j);
}
}
}
}
TopicExchange::~TopicExchange() {}
const std::string TopicExchange::typeName("topic");
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