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CyberPanel/install-two/openlitespeed-1.4.28/include/lsr/ls_tsstack.h
2018-05-29 20:20:05 +05:00

193 lines
5.9 KiB
C

/*****************************************************************************
* Open LiteSpeed is an open source HTTP server. *
* Copyright (C) 2013 - 2015 LiteSpeed Technologies, Inc. *
* *
* This program is free software: you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation, either version 3 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program. If not, see http://www.gnu.org/licenses/. *
*****************************************************************************/
#ifndef LS_TSSTACK_H
#define LS_TSSTACK_H
#include <lsr/ls_lock.h>
#include <lsr/ls_node.h>
#include <lsr/ls_stack.h>
#include <lsr/ls_types.h>
/**
* @file
* This version is the thread safe stack implementation.
* ls_tsstack_ uses spin locks to provide the concurrency protection.
*
* This uses ls_nodei_t as the nodes. In order to use the stack,
* the objects the user wishes to link should either inherit from,
* or contain a ls_nodei_t struct.
*
* Other Versions:
* - lsr/ls_lfstack.h
* - lsr/ls_stack.h
*/
#define LSR_TSSTACK_SLEEP_TIME 250
#ifdef __cplusplus
extern "C" {
#endif
typedef struct ls_tsstack_s
{
ls_stack_t stack;
ls_spinlock_t lock;
} ls_tsstack_t;
/** @ls_tsstack_init
* @brief Initializes a thread safe stack object.
* @details The function initializes an object to manage a
* node-based stack (LIFO).
*
* @param[in] pThis - A pointer to an allocated thread safe stack object.
* @return Void.
*
* @see ls_tsstack_destroy
*/
ls_inline void ls_tsstack_init(ls_tsstack_t *pThis)
{
ls_stack_init(&pThis->stack);
ls_spinlock_setup(&pThis->lock);
}
/** @ls_tsstack_destroy
* @brief Destroys a thread safe stack object.
*
* @param[in] pThis - A pointer to an initialized thread safe stack object.
*
* @see ls_tsstack_init
*/
ls_inline void ls_tsstack_destroy(ls_tsstack_t *pThis)
{
ls_spinlock_lock(&pThis->lock);
ls_stack_destroy(&pThis->stack);
ls_spinlock_unlock(&pThis->lock);
}
/** @ls_tsstack_new
* @brief Creates a new thread safe stack object.
* @details The function allocates and initializes an object
* to manage a node-based stack (LIFO).
*
* @return A pointer to an initialized thread safe stack object,
* else NULL on error.
*
* @see ls_tsstack_delete
*/
ls_tsstack_t *ls_tsstack_new();
/** @ls_tsstack_delete
* @brief Destroys then deletes a thread safe stack object.
* @details The object should have been created with a previous
* successful call to ls_tsstack_new.
*
* @param[in] pThis - A pointer to an initialized thread safe stack object.
* @return Void.
*
* @see ls_tsstack_new
*/
void ls_tsstack_delete(ls_tsstack_t *pThis);
/** @ls_tsstack_trypush
* @brief Tries to push an object onto the top of a thread safe stack.
* @details This function will try to push onto the stack only once.
* It will return immediately, regardless of the result.
*
* @param[in] pThis - A pointer to an initialized thread safe stack object.
* @param[in] pNode - A pointer to the user defined object to push onto
* the queue.
* @return 0 on success, else -1 on failure.
*/
ls_inline int ls_tsstack_trypush(ls_tsstack_t *pThis, ls_nodei_t *pNode)
{
if (ls_spinlock_trylock(&pThis->lock))
return -1;
ls_stack_push(&pThis->stack, pNode);
ls_spinlock_unlock(&pThis->lock);
return 0;
}
/** @ls_tsstack_push
* @brief Pushes an object onto the top of a thread safe stack.
* @details This function will block until it succeeds.
*
* @param[in] pThis - A pointer to an initialized thread safe stack object.
* @param[in] pNode - A pointer to a user defined object to put on the stack.
* @return Void.
*/
ls_inline void ls_tsstack_push(ls_tsstack_t *pThis, ls_nodei_t *pNode)
{
while (1)
{
if (ls_tsstack_trypush(pThis, pNode) == 0)
return;
usleep(LSR_TSSTACK_SLEEP_TIME);
}
}
/** @ls_tsstack_trypop
* @brief Tries to pop an object from the top of a thread safe stack.
* @details This function will try to pop from the stack only once.
* It will return immediately, regardless of result.
*
* @param[in] pThis - A pointer to an initialized thread safe stack object.
* @param[in,out] pRet - A pointer to the popped object if there is one
* available.
* @return 0 on success, else -1 on failure.
* \note If successful, the value stored in pRet is the result of a pop.
* If the stack is empty, this will be NULL.
*/
ls_inline int ls_tsstack_trypop(ls_tsstack_t *pThis, ls_nodei_t **pRet)
{
if (ls_spinlock_trylock(&pThis->lock))
return -1;
*pRet = ls_stack_pop(&pThis->stack);
ls_spinlock_unlock(&pThis->lock);
return 0;
}
/** @ls_tsstack_pop
* @brief Pops an object from the top of a thread safe stack.
* @details This function will block until it succeeds.
*
* @param[in] pThis - A pointer to an initialized thread safe stack object.
* @return A pointer to the object if one exists, else NULL if empty.
*/
ls_inline ls_nodei_t *ls_tsstack_pop(ls_tsstack_t *pThis)
{
ls_nodei_t *pRet;
while (1)
{
if (ls_tsstack_trypop(pThis, &pRet) == 0)
return pRet;
usleep(LSR_TSSTACK_SLEEP_TIME);
}
}
#ifdef __cplusplus
}
#endif
#endif //LS_TSSTACK_H