// bthread - A M:N threading library to make applications more concurrent. // Copyright (c) 2014 Baidu, 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. // Author: Ge,Jun (gejun@baidu.com) // Date: Sun Jul 13 15:04:18 CST 2014 #ifndef BUTIL_OBJECT_POOL_H #define BUTIL_OBJECT_POOL_H #include <cstddef> // size_t // ObjectPool is a derivative class of ResourcePool to allocate and // reuse fixed-size objects without identifiers. namespace butil { // Specialize following classes to override default parameters for type T. // namespace butil { // template <> struct ObjectPoolBlockMaxSize<Foo> { // static const size_t value = 1024; // }; // } // Memory is allocated in blocks, memory size of a block will not exceed: // min(ObjectPoolBlockMaxSize<T>::value, // ObjectPoolBlockMaxItem<T>::value * sizeof(T)) template <typename T> struct ObjectPoolBlockMaxSize { static const size_t value = 64 * 1024; // bytes }; template <typename T> struct ObjectPoolBlockMaxItem { static const size_t value = 256; }; // Free objects of each thread are grouped into a chunk before they are merged // to the global list. Memory size of objects in one free chunk will not exceed: // min(ObjectPoolFreeChunkMaxItem<T>::value(), // ObjectPoolBlockMaxSize<T>::value, // ObjectPoolBlockMaxItem<T>::value * sizeof(T)) template <typename T> struct ObjectPoolFreeChunkMaxItem { static size_t value() { return 256; } }; // ObjectPool calls this function on newly constructed objects. If this // function returns false, the object is destructed immediately and // get_object() shall return NULL. This is useful when the constructor // failed internally(namely ENOMEM). template <typename T> struct ObjectPoolValidator { static bool validate(const T*) { return true; } }; } // namespace butil #include "butil/object_pool_inl.h" namespace butil { // Get an object typed |T|. The object should be cleared before usage. // NOTE: T must be default-constructible. template <typename T> inline T* get_object() { return ObjectPool<T>::singleton()->get_object(); } // Get an object whose constructor is T(arg1) template <typename T, typename A1> inline T* get_object(const A1& arg1) { return ObjectPool<T>::singleton()->get_object(arg1); } // Get an object whose constructor is T(arg1, arg2) template <typename T, typename A1, typename A2> inline T* get_object(const A1& arg1, const A2& arg2) { return ObjectPool<T>::singleton()->get_object(arg1, arg2); } // Return the object |ptr| back. The object is NOT destructed and will be // returned by later get_object<T>. Similar with free/delete, validity of // the object is not checked, user shall not return a not-yet-allocated or // already-returned object otherwise behavior is undefined. // Returns 0 when successful, -1 otherwise. template <typename T> inline int return_object(T* ptr) { return ObjectPool<T>::singleton()->return_object(ptr); } // Reclaim all allocated objects typed T if caller is the last thread called // this function, otherwise do nothing. You rarely need to call this function // manually because it's called automatically when each thread quits. template <typename T> inline void clear_objects() { ObjectPool<T>::singleton()->clear_objects(); } // Get description of objects typed T. // This function is possibly slow because it iterates internal structures. // Don't use it frequently like a "getter" function. template <typename T> ObjectPoolInfo describe_objects() { return ObjectPool<T>::singleton()->describe_objects(); } } // namespace butil #endif // BUTIL_OBJECT_POOL_H