diff options
Diffstat (limited to 'include/apr_pools.h')
| -rw-r--r-- | include/apr_pools.h | 815 |
1 files changed, 815 insertions, 0 deletions
diff --git a/include/apr_pools.h b/include/apr_pools.h new file mode 100644 index 0000000..eae9c21 --- /dev/null +++ b/include/apr_pools.h @@ -0,0 +1,815 @@ +/* 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 APR_POOLS_H +#define APR_POOLS_H + +/** + * @file apr_pools.h + * @brief APR memory allocation + * + * Resource allocation routines... + * + * designed so that we don't have to keep track of EVERYTHING so that + * it can be explicitly freed later (a fundamentally unsound strategy --- + * particularly in the presence of die()). + * + * Instead, we maintain pools, and allocate items (both memory and I/O + * handlers) from the pools --- currently there are two, one for + * per-transaction info, and one for config info. When a transaction is + * over, we can delete everything in the per-transaction apr_pool_t without + * fear, and without thinking too hard about it either. + * + * Note that most operations on pools are not thread-safe: a single pool + * should only be accessed by a single thread at any given time. The one + * exception to this rule is creating a subpool of a given pool: one or more + * threads can safely create subpools at the same time that another thread + * accesses the parent pool. + */ + +#include "apr.h" +#include "apr_errno.h" +#include "apr_general.h" /* for APR_STRINGIFY */ +#define APR_WANT_MEMFUNC /**< for no good reason? */ +#include "apr_want.h" + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * @defgroup apr_pools Memory Pool Functions + * @ingroup APR + * @{ + */ + +/** The fundamental pool type */ +typedef struct apr_pool_t apr_pool_t; + + +/** + * Declaration helper macro to construct apr_foo_pool_get()s. + * + * This standardized macro is used by opaque (APR) data types to return + * the apr_pool_t that is associated with the data type. + * + * APR_POOL_DECLARE_ACCESSOR() is used in a header file to declare the + * accessor function. A typical usage and result would be: + * <pre> + * APR_POOL_DECLARE_ACCESSOR(file); + * becomes: + * APR_DECLARE(apr_pool_t *) apr_file_pool_get(const apr_file_t *thefile); + * </pre> + * @remark Doxygen unwraps this macro (via doxygen.conf) to provide + * actual help for each specific occurrence of apr_foo_pool_get. + * @remark the linkage is specified for APR. It would be possible to expand + * the macros to support other linkages. + */ +#define APR_POOL_DECLARE_ACCESSOR(type) \ + APR_DECLARE(apr_pool_t *) apr_##type##_pool_get \ + (const apr_##type##_t *the##type) + +/** + * Implementation helper macro to provide apr_foo_pool_get()s. + * + * In the implementation, the APR_POOL_IMPLEMENT_ACCESSOR() is used to + * actually define the function. It assumes the field is named "pool". + */ +#define APR_POOL_IMPLEMENT_ACCESSOR(type) \ + APR_DECLARE(apr_pool_t *) apr_##type##_pool_get \ + (const apr_##type##_t *the##type) \ + { return the##type->pool; } + + +/** + * Pool debug levels + * + * <pre> + * | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | + * --------------------------------- + * | | | | | | | | x | General debug code enabled (useful in + * combination with --with-efence). + * + * | | | | | | | x | | Verbose output on stderr (report + * CREATE, CLEAR, DESTROY). + * + * | | | | x | | | | | Verbose output on stderr (report + * PALLOC, PCALLOC). + * + * | | | | | | x | | | Lifetime checking. On each use of a + * pool, check its lifetime. If the pool + * is out of scope, abort(). + * In combination with the verbose flag + * above, it will output LIFE in such an + * event prior to aborting. + * + * | | | | | x | | | | Pool owner checking. On each use of a + * pool, check if the current thread is the + * pool's owner. If not, abort(). In + * combination with the verbose flag above, + * it will output OWNER in such an event + * prior to aborting. Use the debug + * function apr_pool_owner_set() to switch + * a pool's ownership. + * + * When no debug level was specified, assume general debug mode. + * If level 0 was specified, debugging is switched off. + * </pre> + */ +#if defined(APR_POOL_DEBUG) +/* If APR_POOL_DEBUG is blank, we get 1; if it is a number, we get -1. */ +#if (APR_POOL_DEBUG - APR_POOL_DEBUG -1 == 1) +#undef APR_POOL_DEBUG +#define APR_POOL_DEBUG 1 +#endif +#else +#define APR_POOL_DEBUG 0 +#endif + +/** the place in the code where the particular function was called */ +#define APR_POOL__FILE_LINE__ __FILE__ ":" APR_STRINGIFY(__LINE__) + + + +/** A function that is called when allocation fails. */ +typedef int (*apr_abortfunc_t)(int retcode); + +/* + * APR memory structure manipulators (pools, tables, and arrays). + */ + +/* + * Initialization + */ + +/** + * Setup all of the internal structures required to use pools + * @remark Programs do NOT need to call this directly. APR will call this + * automatically from apr_initialize. + * @internal + */ +APR_DECLARE(apr_status_t) apr_pool_initialize(void); + +/** + * Tear down all of the internal structures required to use pools + * @remark Programs do NOT need to call this directly. APR will call this + * automatically from apr_terminate. + * @internal + */ +APR_DECLARE(void) apr_pool_terminate(void); + + +/* + * Pool creation/destruction + */ + +#include "apr_allocator.h" + +/** + * Create a new pool. + * @param newpool The pool we have just created. + * @param parent The parent pool. If this is NULL, the new pool is a root + * pool. If it is non-NULL, the new pool will inherit all + * of its parent pool's attributes, except the apr_pool_t will + * be a sub-pool. + * @param abort_fn A function to use if the pool cannot allocate more memory. + * @param allocator The allocator to use with the new pool. If NULL the + * allocator of the parent pool will be used. + * @remark This function is thread-safe, in the sense that multiple threads + * can safely create subpools of the same parent pool concurrently. + * Similarly, a subpool can be created by one thread at the same + * time that another thread accesses the parent pool. + */ +APR_DECLARE(apr_status_t) apr_pool_create_ex(apr_pool_t **newpool, + apr_pool_t *parent, + apr_abortfunc_t abort_fn, + apr_allocator_t *allocator) + __attribute__((nonnull(1))); + +/** + * Create a new pool. + * @deprecated @see apr_pool_create_unmanaged_ex. + */ +APR_DECLARE(apr_status_t) apr_pool_create_core_ex(apr_pool_t **newpool, + apr_abortfunc_t abort_fn, + apr_allocator_t *allocator); + +/** + * Create a new unmanaged pool. + * @param newpool The pool we have just created. + * @param abort_fn A function to use if the pool cannot allocate more memory. + * @param allocator The allocator to use with the new pool. If NULL a + * new allocator will be created with the new pool as owner. + * @remark An unmanaged pool is a special pool without a parent; it will + * NOT be destroyed upon apr_terminate. It must be explicitly + * destroyed by calling apr_pool_destroy, to prevent memory leaks. + * Use of this function is discouraged, think twice about whether + * you really really need it. + * @warning Any child cleanups registered against the new pool, or + * against sub-pools thereof, will not be executed during an + * invocation of apr_proc_create(), so resources created in an + * "unmanaged" pool hierarchy will leak to child processes. + */ +APR_DECLARE(apr_status_t) apr_pool_create_unmanaged_ex(apr_pool_t **newpool, + apr_abortfunc_t abort_fn, + apr_allocator_t *allocator) + __attribute__((nonnull(1))); + +/** + * Debug version of apr_pool_create_ex. + * @param newpool @see apr_pool_create. + * @param parent @see apr_pool_create. + * @param abort_fn @see apr_pool_create. + * @param allocator @see apr_pool_create. + * @param file_line Where the function is called from. + * This is usually APR_POOL__FILE_LINE__. + * @remark Only available when APR_POOL_DEBUG is defined. + * Call this directly if you have your apr_pool_create_ex + * calls in a wrapper function and wish to override + * the file_line argument to reflect the caller of + * your wrapper function. If you do not have + * apr_pool_create_ex in a wrapper, trust the macro + * and don't call apr_pool_create_ex_debug directly. + */ +APR_DECLARE(apr_status_t) apr_pool_create_ex_debug(apr_pool_t **newpool, + apr_pool_t *parent, + apr_abortfunc_t abort_fn, + apr_allocator_t *allocator, + const char *file_line) + __attribute__((nonnull(1))); + +#if APR_POOL_DEBUG +#define apr_pool_create_ex(newpool, parent, abort_fn, allocator) \ + apr_pool_create_ex_debug(newpool, parent, abort_fn, allocator, \ + APR_POOL__FILE_LINE__) +#endif + +/** + * Debug version of apr_pool_create_core_ex. + * @deprecated @see apr_pool_create_unmanaged_ex_debug. + */ +APR_DECLARE(apr_status_t) apr_pool_create_core_ex_debug(apr_pool_t **newpool, + apr_abortfunc_t abort_fn, + apr_allocator_t *allocator, + const char *file_line); + +/** + * Debug version of apr_pool_create_unmanaged_ex. + * @param newpool @see apr_pool_create_unmanaged. + * @param abort_fn @see apr_pool_create_unmanaged. + * @param allocator @see apr_pool_create_unmanaged. + * @param file_line Where the function is called from. + * This is usually APR_POOL__FILE_LINE__. + * @remark Only available when APR_POOL_DEBUG is defined. + * Call this directly if you have your apr_pool_create_unmanaged_ex + * calls in a wrapper function and wish to override + * the file_line argument to reflect the caller of + * your wrapper function. If you do not have + * apr_pool_create_core_ex in a wrapper, trust the macro + * and don't call apr_pool_create_core_ex_debug directly. + */ +APR_DECLARE(apr_status_t) apr_pool_create_unmanaged_ex_debug(apr_pool_t **newpool, + apr_abortfunc_t abort_fn, + apr_allocator_t *allocator, + const char *file_line) + __attribute__((nonnull(1))); + +#if APR_POOL_DEBUG +#define apr_pool_create_core_ex(newpool, abort_fn, allocator) \ + apr_pool_create_unmanaged_ex_debug(newpool, abort_fn, allocator, \ + APR_POOL__FILE_LINE__) + +#define apr_pool_create_unmanaged_ex(newpool, abort_fn, allocator) \ + apr_pool_create_unmanaged_ex_debug(newpool, abort_fn, allocator, \ + APR_POOL__FILE_LINE__) + +#endif + +/** + * Create a new pool. + * @param newpool The pool we have just created. + * @param parent The parent pool. If this is NULL, the new pool is a root + * pool. If it is non-NULL, the new pool will inherit all + * of its parent pool's attributes, except the apr_pool_t will + * be a sub-pool. + * @remark This function is thread-safe, in the sense that multiple threads + * can safely create subpools of the same parent pool concurrently. + * Similarly, a subpool can be created by one thread at the same + * time that another thread accesses the parent pool. + */ +#if defined(DOXYGEN) +APR_DECLARE(apr_status_t) apr_pool_create(apr_pool_t **newpool, + apr_pool_t *parent); +#else +#if APR_POOL_DEBUG +#define apr_pool_create(newpool, parent) \ + apr_pool_create_ex_debug(newpool, parent, NULL, NULL, \ + APR_POOL__FILE_LINE__) +#else +#define apr_pool_create(newpool, parent) \ + apr_pool_create_ex(newpool, parent, NULL, NULL) +#endif +#endif + +/** + * Create a new unmanaged pool. + * @param newpool The pool we have just created. + */ +#if defined(DOXYGEN) +APR_DECLARE(apr_status_t) apr_pool_create_core(apr_pool_t **newpool); +APR_DECLARE(apr_status_t) apr_pool_create_unmanaged(apr_pool_t **newpool); +#else +#if APR_POOL_DEBUG +#define apr_pool_create_core(newpool) \ + apr_pool_create_unmanaged_ex_debug(newpool, NULL, NULL, \ + APR_POOL__FILE_LINE__) +#define apr_pool_create_unmanaged(newpool) \ + apr_pool_create_unmanaged_ex_debug(newpool, NULL, NULL, \ + APR_POOL__FILE_LINE__) +#else +#define apr_pool_create_core(newpool) \ + apr_pool_create_unmanaged_ex(newpool, NULL, NULL) +#define apr_pool_create_unmanaged(newpool) \ + apr_pool_create_unmanaged_ex(newpool, NULL, NULL) +#endif +#endif + +/** + * Find the pool's allocator + * @param pool The pool to get the allocator from. + */ +APR_DECLARE(apr_allocator_t *) apr_pool_allocator_get(apr_pool_t *pool) + __attribute__((nonnull(1))); + +/** + * Clear all memory in the pool and run all the cleanups. This also destroys all + * subpools. + * @param p The pool to clear + * @remark This does not actually free the memory, it just allows the pool + * to re-use this memory for the next allocation. + * @see apr_pool_destroy() + */ +APR_DECLARE(void) apr_pool_clear(apr_pool_t *p) __attribute__((nonnull(1))); + +/** + * Debug version of apr_pool_clear. + * @param p See: apr_pool_clear. + * @param file_line Where the function is called from. + * This is usually APR_POOL__FILE_LINE__. + * @remark Only available when APR_POOL_DEBUG is defined. + * Call this directly if you have your apr_pool_clear + * calls in a wrapper function and wish to override + * the file_line argument to reflect the caller of + * your wrapper function. If you do not have + * apr_pool_clear in a wrapper, trust the macro + * and don't call apr_pool_destroy_clear directly. + */ +APR_DECLARE(void) apr_pool_clear_debug(apr_pool_t *p, + const char *file_line) + __attribute__((nonnull(1))); + +#if APR_POOL_DEBUG +#define apr_pool_clear(p) \ + apr_pool_clear_debug(p, APR_POOL__FILE_LINE__) +#endif + +/** + * Destroy the pool. This takes similar action as apr_pool_clear() and then + * frees all the memory. + * @param p The pool to destroy + * @remark This will actually free the memory + */ +APR_DECLARE(void) apr_pool_destroy(apr_pool_t *p) __attribute__((nonnull(1))); + +/** + * Debug version of apr_pool_destroy. + * @param p See: apr_pool_destroy. + * @param file_line Where the function is called from. + * This is usually APR_POOL__FILE_LINE__. + * @remark Only available when APR_POOL_DEBUG is defined. + * Call this directly if you have your apr_pool_destroy + * calls in a wrapper function and wish to override + * the file_line argument to reflect the caller of + * your wrapper function. If you do not have + * apr_pool_destroy in a wrapper, trust the macro + * and don't call apr_pool_destroy_debug directly. + */ +APR_DECLARE(void) apr_pool_destroy_debug(apr_pool_t *p, + const char *file_line) + __attribute__((nonnull(1))); + +#if APR_POOL_DEBUG +#define apr_pool_destroy(p) \ + apr_pool_destroy_debug(p, APR_POOL__FILE_LINE__) +#endif + + +/* + * Memory allocation + */ + +/** + * Allocate a block of memory from a pool + * @param p The pool to allocate from + * @param size The amount of memory to allocate + * @return The allocated memory + */ +APR_DECLARE(void *) apr_palloc(apr_pool_t *p, apr_size_t size) +#if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4)) + __attribute__((alloc_size(2))) +#endif + __attribute__((nonnull(1))); + +/** + * Debug version of apr_palloc + * @param p See: apr_palloc + * @param size See: apr_palloc + * @param file_line Where the function is called from. + * This is usually APR_POOL__FILE_LINE__. + * @return See: apr_palloc + */ +APR_DECLARE(void *) apr_palloc_debug(apr_pool_t *p, apr_size_t size, + const char *file_line) +#if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 4)) + __attribute__((alloc_size(2))) +#endif + __attribute__((nonnull(1))); + +#if APR_POOL_DEBUG +#define apr_palloc(p, size) \ + apr_palloc_debug(p, size, APR_POOL__FILE_LINE__) +#endif + +/** + * Allocate a block of memory from a pool and set all of the memory to 0 + * @param p The pool to allocate from + * @param size The amount of memory to allocate + * @return The allocated memory + */ +#if defined(DOXYGEN) +APR_DECLARE(void *) apr_pcalloc(apr_pool_t *p, apr_size_t size); +#elif !APR_POOL_DEBUG +#define apr_pcalloc(p, size) memset(apr_palloc(p, size), 0, size) +#endif + +/** + * Debug version of apr_pcalloc + * @param p See: apr_pcalloc + * @param size See: apr_pcalloc + * @param file_line Where the function is called from. + * This is usually APR_POOL__FILE_LINE__. + * @return See: apr_pcalloc + */ +APR_DECLARE(void *) apr_pcalloc_debug(apr_pool_t *p, apr_size_t size, + const char *file_line) + __attribute__((nonnull(1))); + +#if APR_POOL_DEBUG +#define apr_pcalloc(p, size) \ + apr_pcalloc_debug(p, size, APR_POOL__FILE_LINE__) +#endif + + +/* + * Pool Properties + */ + +/** + * Set the function to be called when an allocation failure occurs. + * @remark If the program wants APR to exit on a memory allocation error, + * then this function can be called to set the callback to use (for + * performing cleanup and then exiting). If this function is not called, + * then APR will return an error and expect the calling program to + * deal with the error accordingly. + */ +APR_DECLARE(void) apr_pool_abort_set(apr_abortfunc_t abortfunc, + apr_pool_t *pool) + __attribute__((nonnull(2))); + +/** + * Get the abort function associated with the specified pool. + * @param pool The pool for retrieving the abort function. + * @return The abort function for the given pool. + */ +APR_DECLARE(apr_abortfunc_t) apr_pool_abort_get(apr_pool_t *pool) + __attribute__((nonnull(1))); + +/** + * Get the parent pool of the specified pool. + * @param pool The pool for retrieving the parent pool. + * @return The parent of the given pool. + */ +APR_DECLARE(apr_pool_t *) apr_pool_parent_get(apr_pool_t *pool) + __attribute__((nonnull(1))); + +/** + * Determine if pool a is an ancestor of pool b. + * @param a The pool to search + * @param b The pool to search for + * @return True if a is an ancestor of b, NULL is considered an ancestor + * of all pools. + * @remark if compiled with APR_POOL_DEBUG, this function will also + * return true if A is a pool which has been guaranteed by the caller + * (using apr_pool_join) to have a lifetime at least as long as some + * ancestor of pool B. + */ +APR_DECLARE(int) apr_pool_is_ancestor(apr_pool_t *a, apr_pool_t *b); + +/** + * Tag a pool (give it a name) + * @param pool The pool to tag + * @param tag The tag + */ +APR_DECLARE(void) apr_pool_tag(apr_pool_t *pool, const char *tag) + __attribute__((nonnull(1))); + + +/* + * User data management + */ + +/** + * Set the data associated with the current pool + * @param data The user data associated with the pool. + * @param key The key to use for association + * @param cleanup The cleanup program to use to cleanup the data (NULL if none) + * @param pool The current pool + * @warning The data to be attached to the pool should have a life span + * at least as long as the pool it is being attached to. + * + * Users of APR must take EXTREME care when choosing a key to + * use for their data. It is possible to accidentally overwrite + * data by choosing a key that another part of the program is using. + * Therefore it is advised that steps are taken to ensure that unique + * keys are used for all of the userdata objects in a particular pool + * (the same key in two different pools or a pool and one of its + * subpools is okay) at all times. Careful namespace prefixing of + * key names is a typical way to help ensure this uniqueness. + * + */ +APR_DECLARE(apr_status_t) apr_pool_userdata_set(const void *data, + const char *key, + apr_status_t (*cleanup)(void *), + apr_pool_t *pool) + __attribute__((nonnull(2,4))); + +/** + * Set the data associated with the current pool + * @param data The user data associated with the pool. + * @param key The key to use for association + * @param cleanup The cleanup program to use to cleanup the data (NULL if none) + * @param pool The current pool + * @note same as apr_pool_userdata_set(), except that this version doesn't + * make a copy of the key (this function is useful, for example, when + * the key is a string literal) + * @warning This should NOT be used if the key could change addresses by + * any means between the apr_pool_userdata_setn() call and a + * subsequent apr_pool_userdata_get() on that key, such as if a + * static string is used as a userdata key in a DSO and the DSO could + * be unloaded and reloaded between the _setn() and the _get(). You + * MUST use apr_pool_userdata_set() in such cases. + * @warning More generally, the key and the data to be attached to the + * pool should have a life span at least as long as the pool itself. + * + */ +APR_DECLARE(apr_status_t) apr_pool_userdata_setn( + const void *data, const char *key, + apr_status_t (*cleanup)(void *), + apr_pool_t *pool) + __attribute__((nonnull(2,4))); + +/** + * Return the data associated with the current pool. + * @param data The user data associated with the pool. + * @param key The key for the data to retrieve + * @param pool The current pool. + */ +APR_DECLARE(apr_status_t) apr_pool_userdata_get(void **data, const char *key, + apr_pool_t *pool) + __attribute__((nonnull(1,2,3))); + + +/** + * @defgroup PoolCleanup Pool Cleanup Functions + * + * Cleanups are performed in the reverse order they were registered. That is: + * Last In, First Out. A cleanup function can safely allocate memory from + * the pool that is being cleaned up. It can also safely register additional + * cleanups which will be run LIFO, directly after the current cleanup + * terminates. Cleanups have to take caution in calling functions that + * create subpools. Subpools, created during cleanup will NOT automatically + * be cleaned up. In other words, cleanups are to clean up after themselves. + * + * @{ + */ + +/** + * Register a function to be called when a pool is cleared or destroyed + * @param p The pool to register the cleanup with + * @param data The data to pass to the cleanup function. + * @param plain_cleanup The function to call when the pool is cleared + * or destroyed + * @param child_cleanup The function to call when a child process is about + * to exec - this function is called in the child, obviously! + */ +APR_DECLARE(void) apr_pool_cleanup_register( + apr_pool_t *p, const void *data, + apr_status_t (*plain_cleanup)(void *), + apr_status_t (*child_cleanup)(void *)) + __attribute__((nonnull(3,4))); + +/** + * Register a function to be called when a pool is cleared or destroyed. + * + * Unlike apr_pool_cleanup_register which registers a cleanup + * that is called AFTER all subpools are destroyed, this function registers + * a function that will be called before any of the subpools are destroyed. + * + * @param p The pool to register the cleanup with + * @param data The data to pass to the cleanup function. + * @param plain_cleanup The function to call when the pool is cleared + * or destroyed + */ +APR_DECLARE(void) apr_pool_pre_cleanup_register( + apr_pool_t *p, const void *data, + apr_status_t (*plain_cleanup)(void *)) + __attribute__((nonnull(3))); + +/** + * Remove a previously registered cleanup function. + * + * The cleanup most recently registered with @a p having the same values of + * @a data and @a cleanup will be removed. + * + * @param p The pool to remove the cleanup from + * @param data The data of the registered cleanup + * @param cleanup The function to remove from cleanup + * @remarks For some strange reason only the plain_cleanup is handled by this + * function + */ +APR_DECLARE(void) apr_pool_cleanup_kill(apr_pool_t *p, const void *data, + apr_status_t (*cleanup)(void *)) + __attribute__((nonnull(3))); + +/** + * Replace the child cleanup function of a previously registered cleanup. + * + * The cleanup most recently registered with @a p having the same values of + * @a data and @a plain_cleanup will have the registered child cleanup + * function replaced with @a child_cleanup. + * + * @param p The pool of the registered cleanup + * @param data The data of the registered cleanup + * @param plain_cleanup The plain cleanup function of the registered cleanup + * @param child_cleanup The function to register as the child cleanup + */ +APR_DECLARE(void) apr_pool_child_cleanup_set( + apr_pool_t *p, const void *data, + apr_status_t (*plain_cleanup)(void *), + apr_status_t (*child_cleanup)(void *)) + __attribute__((nonnull(3,4))); + +/** + * Run the specified cleanup function immediately and unregister it. + * + * The cleanup most recently registered with @a p having the same values of + * @a data and @a cleanup will be removed and @a cleanup will be called + * with @a data as the argument. + * + * @param p The pool to remove the cleanup from + * @param data The data to remove from cleanup + * @param cleanup The function to remove from cleanup + */ +APR_DECLARE(apr_status_t) apr_pool_cleanup_run(apr_pool_t *p, void *data, + apr_status_t (*cleanup)(void *)) + __attribute__((nonnull(3))); + +/** + * An empty cleanup function. + * + * Passed to apr_pool_cleanup_register() when no cleanup is required. + * + * @param data The data to cleanup, will not be used by this function. + */ +APR_DECLARE_NONSTD(apr_status_t) apr_pool_cleanup_null(void *data); + +/** + * Run all registered child cleanups, in preparation for an exec() + * call in a forked child -- close files, etc., but *don't* flush I/O + * buffers, *don't* wait for subprocesses, and *don't* free any + * memory. + */ +APR_DECLARE(void) apr_pool_cleanup_for_exec(void); + +/** @} */ + +/** + * @defgroup PoolDebug Pool Debugging functions + * + * pools have nested lifetimes -- sub_pools are destroyed when the + * parent pool is cleared. We allow certain liberties with operations + * on things such as tables (and on other structures in a more general + * sense) where we allow the caller to insert values into a table which + * were not allocated from the table's pool. The table's data will + * remain valid as long as all the pools from which its values are + * allocated remain valid. + * + * For example, if B is a sub pool of A, and you build a table T in + * pool B, then it's safe to insert data allocated in A or B into T + * (because B lives at most as long as A does, and T is destroyed when + * B is cleared/destroyed). On the other hand, if S is a table in + * pool A, it is safe to insert data allocated in A into S, but it + * is *not safe* to insert data allocated from B into S... because + * B can be cleared/destroyed before A is (which would leave dangling + * pointers in T's data structures). + * + * In general we say that it is safe to insert data into a table T + * if the data is allocated in any ancestor of T's pool. This is the + * basis on which the APR_POOL_DEBUG code works -- it tests these ancestor + * relationships for all data inserted into tables. APR_POOL_DEBUG also + * provides tools (apr_pool_find, and apr_pool_is_ancestor) for other + * folks to implement similar restrictions for their own data + * structures. + * + * However, sometimes this ancestor requirement is inconvenient -- + * sometimes it's necessary to create a sub pool where the sub pool is + * guaranteed to have the same lifetime as the parent pool. This is a + * guarantee implemented by the *caller*, not by the pool code. That + * is, the caller guarantees they won't destroy the sub pool + * individually prior to destroying the parent pool. + * + * In this case the caller must call apr_pool_join() to indicate this + * guarantee to the APR_POOL_DEBUG code. + * + * These functions are only implemented when #APR_POOL_DEBUG is set. + * + * @{ + */ +#if APR_POOL_DEBUG || defined(DOXYGEN) +/** + * Guarantee that a subpool has the same lifetime as the parent. + * @param p The parent pool + * @param sub The subpool + */ +APR_DECLARE(void) apr_pool_join(apr_pool_t *p, apr_pool_t *sub) + __attribute__((nonnull(2))); + +/** + * Find a pool from something allocated in it. + * @param mem The thing allocated in the pool + * @return The pool it is allocated in + */ +APR_DECLARE(apr_pool_t *) apr_pool_find(const void *mem); + +/** + * Report the number of bytes currently in the pool + * @param p The pool to inspect + * @param recurse Recurse/include the subpools' sizes + * @return The number of bytes + */ +APR_DECLARE(apr_size_t) apr_pool_num_bytes(apr_pool_t *p, int recurse) + __attribute__((nonnull(1))); + +/** + * Lock a pool + * @param pool The pool to lock + * @param flag The flag + */ +APR_DECLARE(void) apr_pool_lock(apr_pool_t *pool, int flag); + +/** @} */ + +#else /* APR_POOL_DEBUG or DOXYGEN */ + +#ifdef apr_pool_join +#undef apr_pool_join +#endif +#define apr_pool_join(a,b) + +#ifdef apr_pool_lock +#undef apr_pool_lock +#endif +#define apr_pool_lock(pool, lock) + +#endif /* APR_POOL_DEBUG or DOXYGEN */ + +/** @} */ + +#ifdef __cplusplus +} +#endif + +#endif /* !APR_POOLS_H */ |