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Diffstat (limited to 'src/mapi/glapi/glapi.c')
| -rw-r--r-- | src/mapi/glapi/glapi.c | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/src/mapi/glapi/glapi.c b/src/mapi/glapi/glapi.c new file mode 100644 index 0000000000..ce85cf6a87 --- /dev/null +++ b/src/mapi/glapi/glapi.c @@ -0,0 +1,293 @@ +/* + * Mesa 3-D graphics library + * Version: 7.1 + * + * Copyright (C) 1999-2008 Brian Paul All Rights Reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included + * in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS + * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN + * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + + +/* + * This file manages the OpenGL API dispatch layer. + * The dispatch table (struct _glapi_table) is basically just a list + * of function pointers. + * There are functions to set/get the current dispatch table for the + * current thread and to manage registration/dispatch of dynamically + * added extension functions. + * + * It's intended that this file and the other glapi*.[ch] files are + * flexible enough to be reused in several places: XFree86, DRI- + * based libGL.so, and perhaps the SGI SI. + * + * NOTE: There are no dependencies on Mesa in this code. + * + * Versions (API changes): + * 2000/02/23 - original version for Mesa 3.3 and XFree86 4.0 + * 2001/01/16 - added dispatch override feature for Mesa 3.5 + * 2002/06/28 - added _glapi_set_warning_func(), Mesa 4.1. + * 2002/10/01 - _glapi_get_proc_address() will now generate new entrypoints + * itself (using offset ~0). _glapi_add_entrypoint() can be + * called afterward and it'll fill in the correct dispatch + * offset. This allows DRI libGL to avoid probing for DRI + * drivers! No changes to the public glapi interface. + */ + + + +#ifdef HAVE_DIX_CONFIG_H +#include <dix-config.h> +#include "glapi/mesa.h" +#else +#include "main/glheader.h" +#include "main/compiler.h" +#endif + +#include "glapi/glapi.h" +#include "glapi/glapi_priv.h" + +extern _glapi_proc __glapi_noop_table[]; + + +/** + * \name Current dispatch and current context control variables + * + * Depending on whether or not multithreading is support, and the type of + * support available, several variables are used to store the current context + * pointer and the current dispatch table pointer. In the non-threaded case, + * the variables \c _glapi_Dispatch and \c _glapi_Context are used for this + * purpose. + * + * In the "normal" threaded case, the variables \c _glapi_Dispatch and + * \c _glapi_Context will be \c NULL if an application is detected as being + * multithreaded. Single-threaded applications will use \c _glapi_Dispatch + * and \c _glapi_Context just like the case without any threading support. + * When \c _glapi_Dispatch and \c _glapi_Context are \c NULL, the thread state + * data \c _gl_DispatchTSD and \c ContextTSD are used. Drivers and the + * static dispatch functions access these variables via \c _glapi_get_dispatch + * and \c _glapi_get_context. + * + * There is a race condition in setting \c _glapi_Dispatch to \c NULL. It is + * possible for the original thread to be setting it at the same instant a new + * thread, perhaps running on a different processor, is clearing it. Because + * of that, \c ThreadSafe, which can only ever be changed to \c GL_TRUE, is + * used to determine whether or not the application is multithreaded. + * + * In the TLS case, the variables \c _glapi_Dispatch and \c _glapi_Context are + * hardcoded to \c NULL. Instead the TLS variables \c _glapi_tls_Dispatch and + * \c _glapi_tls_Context are used. Having \c _glapi_Dispatch and + * \c _glapi_Context be hardcoded to \c NULL maintains binary compatability + * between TLS enabled loaders and non-TLS DRI drivers. + */ +/*@{*/ +#if defined(GLX_USE_TLS) + +PUBLIC __thread struct _glapi_table * _glapi_tls_Dispatch + __attribute__((tls_model("initial-exec"))) + = (struct _glapi_table *) __glapi_noop_table; + +PUBLIC __thread void * _glapi_tls_Context + __attribute__((tls_model("initial-exec"))); + +PUBLIC const struct _glapi_table *_glapi_Dispatch = NULL; + +PUBLIC const void *_glapi_Context = NULL; + +#else + +#if defined(THREADS) + +static GLboolean ThreadSafe = GL_FALSE; /**< In thread-safe mode? */ + +_glthread_TSD _gl_DispatchTSD; /**< Per-thread dispatch pointer */ + +static _glthread_TSD ContextTSD; /**< Per-thread context pointer */ + +#endif /* defined(THREADS) */ + +PUBLIC struct _glapi_table *_glapi_Dispatch = (struct _glapi_table *) __glapi_noop_table; + +PUBLIC void *_glapi_Context = NULL; + +#endif /* defined(GLX_USE_TLS) */ +/*@}*/ + + + +#if defined(THREADS) && !defined(GLX_USE_TLS) + +void +_glapi_init_multithread(void) +{ + _glthread_InitTSD(&_gl_DispatchTSD); + _glthread_InitTSD(&ContextTSD); +} + +void +_glapi_destroy_multithread(void) +{ +#ifdef WIN32_THREADS + _glthread_DestroyTSD(&_gl_DispatchTSD); + _glthread_DestroyTSD(&ContextTSD); +#endif +} + +/** + * Mutex for multithread check. + */ +#ifdef WIN32_THREADS +/* _glthread_DECLARE_STATIC_MUTEX is broken on windows. There will be race! */ +#define CHECK_MULTITHREAD_LOCK() +#define CHECK_MULTITHREAD_UNLOCK() +#else +_glthread_DECLARE_STATIC_MUTEX(ThreadCheckMutex); +#define CHECK_MULTITHREAD_LOCK() _glthread_LOCK_MUTEX(ThreadCheckMutex) +#define CHECK_MULTITHREAD_UNLOCK() _glthread_UNLOCK_MUTEX(ThreadCheckMutex) +#endif + +/** + * We should call this periodically from a function such as glXMakeCurrent + * in order to test if multiple threads are being used. + */ +PUBLIC void +_glapi_check_multithread(void) +{ + static unsigned long knownID; + static GLboolean firstCall = GL_TRUE; + + if (ThreadSafe) + return; + + CHECK_MULTITHREAD_LOCK(); + if (firstCall) { + _glapi_init_multithread(); + + knownID = _glthread_GetID(); + firstCall = GL_FALSE; + } + else if (knownID != _glthread_GetID()) { + ThreadSafe = GL_TRUE; + _glapi_set_dispatch(NULL); + _glapi_set_context(NULL); + } + CHECK_MULTITHREAD_UNLOCK(); +} + +#else + +void +_glapi_init_multithread(void) { } + +void +_glapi_destroy_multithread(void) { } + +PUBLIC void +_glapi_check_multithread(void) { } + +#endif + + + +/** + * Set the current context pointer for this thread. + * The context pointer is an opaque type which should be cast to + * void from the real context pointer type. + */ +PUBLIC void +_glapi_set_context(void *context) +{ +#if defined(GLX_USE_TLS) + _glapi_tls_Context = context; +#elif defined(THREADS) + _glthread_SetTSD(&ContextTSD, context); + _glapi_Context = (ThreadSafe) ? NULL : context; +#else + _glapi_Context = context; +#endif +} + + + +/** + * Get the current context pointer for this thread. + * The context pointer is an opaque type which should be cast from + * void to the real context pointer type. + */ +PUBLIC void * +_glapi_get_context(void) +{ +#if defined(GLX_USE_TLS) + return _glapi_tls_Context; +#elif defined(THREADS) + return (ThreadSafe) ? _glthread_GetTSD(&ContextTSD) : _glapi_Context; +#else + return _glapi_Context; +#endif +} + + + +/** + * Set the global or per-thread dispatch table pointer. + * If the dispatch parameter is NULL we'll plug in the no-op dispatch + * table (__glapi_noop_table). + */ +PUBLIC void +_glapi_set_dispatch(struct _glapi_table *dispatch) +{ + init_glapi_relocs_once(); + + if (dispatch == NULL) { + /* use the no-op functions */ + dispatch = (struct _glapi_table *) __glapi_noop_table; + } +#ifdef DEBUG + else { + _glapi_check_table_not_null(dispatch); + _glapi_check_table(dispatch); + } +#endif + +#if defined(GLX_USE_TLS) + _glapi_tls_Dispatch = dispatch; +#elif defined(THREADS) + _glthread_SetTSD(&_gl_DispatchTSD, (void *) dispatch); + _glapi_Dispatch = (ThreadSafe) ? NULL : dispatch; +#else + _glapi_Dispatch = dispatch; +#endif +} + + + +/** + * Return pointer to current dispatch table for calling thread. + */ +PUBLIC struct _glapi_table * +_glapi_get_dispatch(void) +{ +#if defined(GLX_USE_TLS) + return _glapi_tls_Dispatch; +#elif defined(THREADS) + return (ThreadSafe) + ? (struct _glapi_table *) _glthread_GetTSD(&_gl_DispatchTSD) + : _glapi_Dispatch; +#else + return _glapi_Dispatch; +#endif +} |