github.com/krum110487/go-htaccess@v0.0.0-20240316004156-60641c8e7598/tests/data/apache_2_2_34/include/apr_global_mutex.h (about)

     1  /* Licensed to the Apache Software Foundation (ASF) under one or more
     2   * contributor license agreements.  See the NOTICE file distributed with
     3   * this work for additional information regarding copyright ownership.
     4   * The ASF licenses this file to You under the Apache License, Version 2.0
     5   * (the "License"); you may not use this file except in compliance with
     6   * the License.  You may obtain a copy of the License at
     7   *
     8   *     http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  #ifndef APR_GLOBAL_MUTEX_H
    18  #define APR_GLOBAL_MUTEX_H
    19  
    20  /**
    21   * @file apr_global_mutex.h
    22   * @brief APR Global Locking Routines
    23   */
    24  
    25  #include "apr.h"
    26  #include "apr_proc_mutex.h"    /* only for apr_lockmech_e */
    27  #include "apr_pools.h"
    28  #include "apr_errno.h"
    29  #if APR_PROC_MUTEX_IS_GLOBAL
    30  #include "apr_proc_mutex.h"
    31  #endif
    32  
    33  #ifdef __cplusplus
    34  extern "C" {
    35  #endif /* __cplusplus */
    36  
    37  /**
    38   * @defgroup APR_GlobalMutex Global Locking Routines
    39   * @ingroup APR 
    40   * @{
    41   */
    42  
    43  #if !APR_PROC_MUTEX_IS_GLOBAL || defined(DOXYGEN)
    44  
    45  /** Opaque global mutex structure. */
    46  typedef struct apr_global_mutex_t apr_global_mutex_t;
    47  
    48  /*   Function definitions */
    49  
    50  /**
    51   * Create and initialize a mutex that can be used to synchronize both
    52   * processes and threads. Note: There is considerable overhead in using
    53   * this API if only cross-process or cross-thread mutual exclusion is
    54   * required. See apr_proc_mutex.h and apr_thread_mutex.h for more
    55   * specialized lock routines.
    56   * @param mutex the memory address where the newly created mutex will be
    57   *        stored.
    58   * @param fname A file name to use if the lock mechanism requires one.  This
    59   *        argument should always be provided.  The lock code itself will
    60   *        determine if it should be used.
    61   * @param mech The mechanism to use for the interprocess lock, if any; one of
    62   * <PRE>
    63   *            APR_LOCK_FCNTL
    64   *            APR_LOCK_FLOCK
    65   *            APR_LOCK_SYSVSEM
    66   *            APR_LOCK_POSIXSEM
    67   *            APR_LOCK_PROC_PTHREAD
    68   *            APR_LOCK_DEFAULT     pick the default mechanism for the platform
    69   * </PRE>
    70   * @param pool the pool from which to allocate the mutex.
    71   * @warning Check APR_HAS_foo_SERIALIZE defines to see if the platform supports
    72   *          APR_LOCK_foo.  Only APR_LOCK_DEFAULT is portable.
    73   */
    74  APR_DECLARE(apr_status_t) apr_global_mutex_create(apr_global_mutex_t **mutex,
    75                                                    const char *fname,
    76                                                    apr_lockmech_e mech,
    77                                                    apr_pool_t *pool);
    78  
    79  /**
    80   * Re-open a mutex in a child process.
    81   * @param mutex The newly re-opened mutex structure.
    82   * @param fname A file name to use if the mutex mechanism requires one.  This
    83   *              argument should always be provided.  The mutex code itself will
    84   *              determine if it should be used.  This filename should be the 
    85   *              same one that was passed to apr_global_mutex_create().
    86   * @param pool The pool to operate on.
    87   * @remark This function must be called to maintain portability, even
    88   *         if the underlying lock mechanism does not require it.
    89   */
    90  APR_DECLARE(apr_status_t) apr_global_mutex_child_init(
    91                                apr_global_mutex_t **mutex,
    92                                const char *fname,
    93                                apr_pool_t *pool);
    94  
    95  /**
    96   * Acquire the lock for the given mutex. If the mutex is already locked,
    97   * the current thread will be put to sleep until the lock becomes available.
    98   * @param mutex the mutex on which to acquire the lock.
    99   */
   100  APR_DECLARE(apr_status_t) apr_global_mutex_lock(apr_global_mutex_t *mutex);
   101  
   102  /**
   103   * Attempt to acquire the lock for the given mutex. If the mutex has already
   104   * been acquired, the call returns immediately with APR_EBUSY. Note: it
   105   * is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine
   106   * if the return value was APR_EBUSY, for portability reasons.
   107   * @param mutex the mutex on which to attempt the lock acquiring.
   108   */
   109  APR_DECLARE(apr_status_t) apr_global_mutex_trylock(apr_global_mutex_t *mutex);
   110  
   111  /**
   112   * Release the lock for the given mutex.
   113   * @param mutex the mutex from which to release the lock.
   114   */
   115  APR_DECLARE(apr_status_t) apr_global_mutex_unlock(apr_global_mutex_t *mutex);
   116  
   117  /**
   118   * Destroy the mutex and free the memory associated with the lock.
   119   * @param mutex the mutex to destroy.
   120   */
   121  APR_DECLARE(apr_status_t) apr_global_mutex_destroy(apr_global_mutex_t *mutex);
   122  
   123  /**
   124   * Return the name of the lockfile for the mutex, or NULL
   125   * if the mutex doesn't use a lock file
   126   */
   127  APR_DECLARE(const char *) apr_global_mutex_lockfile(apr_global_mutex_t *mutex);
   128  
   129  /**
   130   * Display the name of the mutex, as it relates to the actual method used
   131   * for the underlying apr_proc_mutex_t, if any.  NULL is returned if
   132   * there is no underlying apr_proc_mutex_t.
   133   * @param mutex the name of the mutex
   134   */
   135  APR_DECLARE(const char *) apr_global_mutex_name(apr_global_mutex_t *mutex);
   136  
   137  /**
   138   * Get the pool used by this global_mutex.
   139   * @return apr_pool_t the pool
   140   */
   141  APR_POOL_DECLARE_ACCESSOR(global_mutex);
   142  
   143  #else /* APR_PROC_MUTEX_IS_GLOBAL */
   144  
   145  /* Some platforms [e.g. Win32] have cross process locks that are truly
   146   * global locks, since there isn't the concept of cross-process locks.
   147   * Define these platforms in terms of an apr_proc_mutex_t.
   148   */
   149  
   150  #define apr_global_mutex_t          apr_proc_mutex_t
   151  #define apr_global_mutex_create     apr_proc_mutex_create
   152  #define apr_global_mutex_child_init apr_proc_mutex_child_init
   153  #define apr_global_mutex_lock       apr_proc_mutex_lock
   154  #define apr_global_mutex_trylock    apr_proc_mutex_trylock
   155  #define apr_global_mutex_unlock     apr_proc_mutex_unlock
   156  #define apr_global_mutex_destroy    apr_proc_mutex_destroy
   157  #define apr_global_mutex_lockfile   apr_proc_mutex_lockfile
   158  #define apr_global_mutex_name       apr_proc_mutex_name
   159  #define apr_global_mutex_pool_get   apr_proc_mutex_pool_get
   160  
   161  #endif
   162  
   163  /** @} */
   164  
   165  #ifdef __cplusplus
   166  }
   167  #endif
   168  
   169  #endif  /* ndef APR_GLOBAL_MUTEX_H */