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Diffstat (limited to 'indra/llcommon/llaprpool.h')
| -rw-r--r-- | indra/llcommon/llaprpool.h | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/indra/llcommon/llaprpool.h b/indra/llcommon/llaprpool.h new file mode 100644 index 0000000000..bf4102c584 --- /dev/null +++ b/indra/llcommon/llaprpool.h @@ -0,0 +1,256 @@ +/** + * @file llaprpool.h + * @brief Implementation of LLAPRPool + * + * $LicenseInfo:firstyear=2011&license=viewerlgpl$ + * Second Life Viewer Source Code + * Copyright (C) 2011, Linden Research, Inc. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; + * version 2.1 of the License only. + * + * This library 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 + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + * + * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA + * $/LicenseInfo$ + * + * CHANGELOG + * and additional copyright holders. + * + * 04/04/2010 + * - Initial version, written by Aleric Inglewood @ SL + * + * 10/11/2010 + * - Added APR_HAS_THREADS #if's to allow creation and destruction + * of subpools by threads other than the parent pool owner. + * + * 05/02/2011 + * - Fixed compilation on windows: Suppress compile warning 4996 + * and include <winsock2.h> before including <ws2tcpip.h>, + * by Merov Linden @ SL. + */ + +#ifndef LL_LLAPRPOOL_H +#define LL_LLAPRPOOL_H + +#ifdef LL_WINDOWS +#pragma warning(push) +#pragma warning(disable:4996) +#include <winsock2.h> +#include <ws2tcpip.h> // Needed before including apr_portable.h +#pragma warning(pop) +#endif + +#include "apr_portable.h" +#include "apr_pools.h" +#include "llerror.h" + +extern void ll_init_apr(); + +/** + * @brief A wrapper around the APR memory pool API. + * + * Usage of this class should be restricted to passing it to libapr-1 function calls that need it. + * + */ +class LL_COMMON_API LLAPRPool +{ +protected: + //! Pointer to the underlaying pool. NULL if not initialized. + apr_pool_t* mPool; // The use of apr_pool_t is OK here. + // This is the wrapped pointer that it is all about! + //! Pointer to the parent pool, if any. Only valid when mPool is non-zero. + LLAPRPool* mParent; + //! The thread that owns this memory pool. Only valid when mPool is non-zero. + apr_os_thread_t mOwner; + +public: + /// Construct an uninitialized (destructed) pool. + LLAPRPool(void) : mPool(NULL) { } + + /// Construct a subpool from an existing pool. + /// This is not a copy-constructor, this class doesn't have one! + LLAPRPool(LLAPRPool& parent) : mPool(NULL) { create(parent); } + + /// Destruct the memory pool (free all of its subpools and allocated memory). + ~LLAPRPool() { destroy(); } + +protected: + /// Create a pool that is allocated from the Operating System. Only used by LLAPRRootPool. + LLAPRPool(int) : mPool(NULL), mParent(NULL), mOwner(apr_os_thread_current()) + { + apr_status_t const apr_pool_create_status = apr_pool_create(&mPool, NULL); + llassert_always(apr_pool_create_status == APR_SUCCESS); + llassert(mPool); + apr_pool_cleanup_register(mPool, this, &s_plain_cleanup, &apr_pool_cleanup_null); + } + +public: + /// Create a subpool from parent. May only be called for an uninitialized/destroyed pool. + /// The default parameter causes the root pool of the current thread to be used. + void create(LLAPRPool& parent = *static_cast<LLAPRPool*>(NULL)); + + /// Destroy the (sub)pool, if any. + void destroy(void); + + // Use some safebool idiom (http://www.artima.com/cppsource/safebool.html) rather than operator bool. + typedef LLAPRPool* const LLAPRPool::* const bool_type; + /// Return true if the pool is initialized. + operator bool_type() const { return mPool ? &LLAPRPool::mParent : 0; } + + /// Painful, but we have to either provide access to this, or wrap + /// every APR function call that needs an apr pool as argument. + /// NEVER destroy a pool that is returned by this function! + apr_pool_t* operator()(void) const // The use of apr_pool_t is OK here. + // This is the accessor for passing the pool to libapr-1 functions. + { + llassert(mPool); + llassert(apr_os_thread_equal(mOwner, apr_os_thread_current())); + return mPool; + } + + /// Free all memory without destructing the pool. + void clear(void) + { + llassert(mPool); + llassert(apr_os_thread_equal(mOwner, apr_os_thread_current())); + apr_pool_clear(mPool); + } + +// These methods would make this class 'complete' (as wrapper around the libapr +// pool functions), but we don't use memory pools in the viewer (only when +// we are forced to pass one to a libapr call), so don't define them in order +// not to encourage people to use them. +#if 0 + void* palloc(size_t size) + { + llassert(mPool); + llassert(apr_os_thread_equal(mOwner, apr_os_thread_current())); + return apr_palloc(mPool, size); + } + void* pcalloc(size_t size) + { + llassert(mPool); + llassert(apr_os_thread_equal(mOwner, apr_os_thread_current())); + return apr_pcalloc(mPool, size); + } +#endif + +private: + bool parent_is_being_destructed(void); + static apr_status_t s_plain_cleanup(void* userdata) { return static_cast<LLAPRPool*>(userdata)->plain_cleanup(); } + + apr_status_t plain_cleanup(void) + { + if (mPool && // We are not being destructed, + parent_is_being_destructed()) // but our parent is. + // This means the pool is being destructed recursively by libapr + // because one of its parents is being destructed. + { + mPool = NULL; // Stop destroy() from destructing the pool again. + } + return APR_SUCCESS; + } +}; + +class LLAPRInitialization +{ +public: + LLAPRInitialization(void); +}; + +/** + * @brief Root memory pool (allocates memory from the operating system). + * + * This class should only be used by LLThreadLocalData + * (and LLMutexRootPool when APR_HAS_THREADS isn't defined). + */ +class LL_COMMON_API LLAPRRootPool : public LLAPRInitialization, public LLAPRPool +{ +private: + /// Construct a root memory pool. Should only be used by LLThreadLocalData and LLMutexRootPool. + friend class LLThreadLocalData; +#if !APR_HAS_THREADS + friend class LLMutexRootPool; +#endif + /// Construct a root memory pool. + /// Should only be used by LLThreadLocalData. + LLAPRRootPool(void); + ~LLAPRRootPool(); + +private: + // Keep track of how many root pools exist and when the last one is destructed. + static bool sCountInitialized; + static apr_uint32_t volatile sCount; + +public: + // Return a global root pool that is independent of LLThreadLocalData. + // Normally you should not use this. Only use for early initialization + // (before main) and deinitialization (after main). + static LLAPRRootPool& get(void); + +#if APR_POOL_DEBUG + void grab_ownership(void) + { + // You need a patched libapr to use this. + // See http://web.archiveorange.com/archive/v/5XO9y2zoxUOMt6Gmi1OI + apr_pool_owner_set(mPool); + } +#endif + +private: + // Used for constructing the Special Global Root Pool (returned by LLAPRRootPool::get). + // It is the same as the default constructor but omits to increment sCount. As a result, + // we must be sure that at least one other LLAPRRootPool is created before termination + // of the application (which is the case: we create one LLAPRRootPool per thread). + LLAPRRootPool(int) : LLAPRInitialization(), LLAPRPool(0) { } +}; + +/** Volatile memory pool + * + * 'Volatile' APR memory pool which normally only clears memory, + * and does not destroy the pool (the same pool is reused) for + * greater efficiency. However, as a safe guard the apr pool + * is destructed every FULL_VOLATILE_APR_POOL uses to allow + * the system memory to be allocated more efficiently and not + * get scattered through RAM. + */ +class LL_COMMON_API LLVolatileAPRPool : protected LLAPRPool +{ +public: + LLVolatileAPRPool(void) : mNumActiveRef(0), mNumTotalRef(0) { } + + void clearVolatileAPRPool(void); + + bool isOld(void) const { return mNumTotalRef > FULL_VOLATILE_APR_POOL; } + bool isUnused() const { return mNumActiveRef == 0; } + +private: + friend class LLScopedVolatileAPRPool; + friend class LLAPRFile; + apr_pool_t* getVolatileAPRPool(void) // The use of apr_pool_t is OK here. + { + if (!mPool) create(); + ++mNumActiveRef; + ++mNumTotalRef; + return LLAPRPool::operator()(); + } + +private: + S32 mNumActiveRef; // Number of active uses of the pool. + S32 mNumTotalRef; // Number of total uses of the pool since last creation. + + // Maximum number of references to LLVolatileAPRPool until the pool is recreated. + static S32 const FULL_VOLATILE_APR_POOL = 1024; +}; + +#endif // LL_LLAPRPOOL_H |