blob: 168b6595173516c2e62793affa7125eebbf82d77 [file] [log] [blame]
/*
* Copyright 2015 Facebook, Inc.
*
* Licensed 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.
*/
#pragma once
#include <atomic>
#include <climits>
#include <functional>
#include <stdexcept>
namespace folly {
typedef std::function<void()> Func;
/// An Executor accepts units of work with add(), which should be
/// threadsafe.
class Executor {
public:
virtual ~Executor() = default;
/// Enqueue a function to executed by this executor. This and all
/// variants must be threadsafe.
virtual void add(Func) = 0;
/// Enqueue a function with a given priority, where 0 is the medium priority
/// This is up to the implementation to enforce
virtual void addWithPriority(Func, int8_t /*priority*/) {
throw std::runtime_error(
"addWithPriority() is not implemented for this Executor");
}
virtual uint8_t getNumPriorities() const {
return 1;
}
static const int8_t LO_PRI = SCHAR_MIN;
static const int8_t MID_PRI = 0;
static const int8_t HI_PRI = SCHAR_MAX;
/// A convenience function for shared_ptr to legacy functors.
///
/// Sometimes you have a functor that is move-only, and therefore can't be
/// converted to a std::function (e.g. std::packaged_task). In that case,
/// wrap it in a shared_ptr (or maybe folly::MoveWrapper) and use this.
template <class P>
void addPtr(P fn) {
this->add([fn]() mutable { (*fn)(); });
}
};
} // folly