rocksdb/thrift/lib/cpp/concurrency/FunctionRunner.h

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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.
*/
#ifndef _THRIFT_CONCURRENCY_FUNCTION_RUNNER_H
#define _THRIFT_CONCURRENCY_FUNCTION_RUNNER_H 1
#include <tr1/functional>
#include "thrift/lib/cpp/concurrency/Thread.h"
namespace apache { namespace thrift { namespace concurrency {
/**
* Convenient implementation of Runnable that will execute arbitrary callbacks.
* Interfaces are provided to accept both a generic 'void(void)' callback, and
* a 'void* (void*)' pthread_create-style callback.
*
* Example use:
* void* my_thread_main(void* arg);
* shared_ptr<ThreadFactory> factory = ...;
* // To create a thread that executes my_thread_main once:
* shared_ptr<Thread> thread = factory->newThread(
* FunctionRunner::create(my_thread_main, some_argument));
* thread->start();
*
* bool A::foo();
* A* a = new A();
* // To create a thread that executes a.foo() every 100 milliseconds:
* factory->newThread(FunctionRunner::create(
* std::tr1::bind(&A::foo, a), 100))->start();
*
*/
class FunctionRunner : public Runnable {
public:
// This is the type of callback 'pthread_create()' expects.
typedef void* (*PthreadFuncPtr)(void *arg);
// This a fully-generic void(void) callback for custom bindings.
typedef std::tr1::function<void()> VoidFunc;
typedef std::tr1::function<bool()> BoolFunc;
/**
* Syntactic sugar to make it easier to create new FunctionRunner
* objects wrapped in shared_ptr.
*/
static boost::shared_ptr<FunctionRunner> create(const VoidFunc& cob) {
return boost::shared_ptr<FunctionRunner>(new FunctionRunner(cob));
}
static boost::shared_ptr<FunctionRunner> create(PthreadFuncPtr func,
void* arg) {
return boost::shared_ptr<FunctionRunner>(new FunctionRunner(func, arg));
}
static boost::shared_ptr<FunctionRunner> create(const BoolFunc& cob,
int intervalMs) {
return boost::shared_ptr<FunctionRunner>(new FunctionRunner(cob,
intervalMs));
}
/**
* Given a 'pthread_create' style callback, this FunctionRunner will
* execute the given callback. Note that the 'void*' return value is ignored.
*/
FunctionRunner(PthreadFuncPtr func, void* arg)
: func_(std::tr1::bind(func, arg)), repFunc_(0), initFunc_(0)
{ }
/**
* Given a generic callback, this FunctionRunner will execute it.
*/
FunctionRunner(const VoidFunc& cob)
: func_(cob), repFunc_(0), initFunc_(0)
{ }
/**
* Given a bool foo(...) type callback, FunctionRunner will execute
* the callback repeatedly with 'intervalMs' milliseconds between the calls,
* until it returns false. Note that the actual interval between calls will
* be intervalMs plus execution time of the callback.
*/
FunctionRunner(const BoolFunc& cob, int intervalMs)
: func_(0), repFunc_(cob), intervalMs_(intervalMs), initFunc_(0)
{ }
/**
* Set a callback to be called when the thread is started.
*/
void setInitFunc(const VoidFunc& initFunc) {
initFunc_ = initFunc;
}
void run() {
if (initFunc_) {
initFunc_();
}
if (repFunc_) {
while(repFunc_()) {
usleep(intervalMs_*1000);
}
} else {
func_();
}
}
private:
VoidFunc func_;
BoolFunc repFunc_;
int intervalMs_;
VoidFunc initFunc_;
};
}}} // apache::thrift::concurrency
#endif // #ifndef _THRIFT_CONCURRENCY_FUNCTION_RUNNER_H