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Diffstat (limited to 'mesalib/src/mapi/u_current.c')
| -rw-r--r-- | mesalib/src/mapi/u_current.c | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/mesalib/src/mapi/u_current.c b/mesalib/src/mapi/u_current.c new file mode 100644 index 000000000..344344939 --- /dev/null +++ b/mesalib/src/mapi/u_current.c @@ -0,0 +1,267 @@ +/* + * 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 + * THE AUTHORS OR COPYRIGHT HOLDERS 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. + */ + +#include "u_current.h" +#include "u_thread.h" + +#ifndef MAPI_MODE_UTIL + +#include "table.h" +#include "stub.h" + +#else + +extern void init_glapi_relocs_once(void); +extern void (*__glapi_noop_table[])(void); + +#define table_noop_array __glapi_noop_table +#define stub_init_once() init_glapi_relocs_once() + +#endif + +/** + * \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) + +__thread struct mapi_table *u_current_table + __attribute__((tls_model("initial-exec"))) + = (struct mapi_table *) table_noop_array; + +__thread void *u_current_user + __attribute__((tls_model("initial-exec"))); + +#else + +struct mapi_table *u_current_table = + (struct mapi_table *) table_noop_array; +void *u_current_user; + +#ifdef THREADS +struct u_tsd u_current_table_tsd; +static struct u_tsd u_current_user_tsd; +static int ThreadSafe; +#endif /* THREADS */ + +#endif /* defined(GLX_USE_TLS) */ +/*@}*/ + + +void +u_current_destroy(void) +{ +#if defined(THREADS) && defined(_WIN32) + u_tsd_destroy(&u_current_table_tsd); + u_tsd_destroy(&u_current_user_tsd); +#endif +} + + +#if defined(THREADS) && !defined(GLX_USE_TLS) + +static void +u_current_init_tsd(void) +{ + u_tsd_init(&u_current_table_tsd); + u_tsd_init(&u_current_user_tsd); +} + +/** + * Mutex for multithread check. + */ +u_mutex_declare_static(ThreadCheckMutex); + +/** + * We should call this periodically from a function such as glXMakeCurrent + * in order to test if multiple threads are being used. + */ +void +u_current_init(void) +{ + static unsigned long knownID; + static int firstCall = 1; + + if (ThreadSafe) + return; + + u_mutex_lock(ThreadCheckMutex); + if (firstCall) { + u_current_init_tsd(); + + knownID = u_thread_self(); + firstCall = 0; + } + else if (knownID != u_thread_self()) { + ThreadSafe = 1; + u_current_set(NULL); + u_current_set_user(NULL); + } + u_mutex_unlock(ThreadCheckMutex); +} + +#else + +void +u_current_init(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. + */ +void +u_current_set_user(const void *ptr) +{ + u_current_init(); + +#if defined(GLX_USE_TLS) + u_current_user = (void *) ptr; +#elif defined(THREADS) + u_tsd_set(&u_current_user_tsd, (void *) ptr); + u_current_user = (ThreadSafe) ? NULL : (void *) ptr; +#else + u_current_user = (void *) ptr; +#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. + */ +void * +u_current_get_user_internal(void) +{ +#if defined(GLX_USE_TLS) + return u_current_user; +#elif defined(THREADS) + return (ThreadSafe) + ? u_tsd_get(&u_current_user_tsd) + : u_current_user; +#else + return u_current_user; +#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). + */ +void +u_current_set(const struct mapi_table *tbl) +{ + u_current_init(); + + stub_init_once(); + + if (!tbl) + tbl = (const struct mapi_table *) table_noop_array; + +#if defined(GLX_USE_TLS) + u_current_table = (struct mapi_table *) tbl; +#elif defined(THREADS) + u_tsd_set(&u_current_table_tsd, (void *) tbl); + u_current_table = (ThreadSafe) ? NULL : (void *) tbl; +#else + u_current_table = (struct mapi_table *) tbl; +#endif +} + +/** + * Return pointer to current dispatch table for calling thread. + */ +struct mapi_table * +u_current_get_internal(void) +{ +#if defined(GLX_USE_TLS) + return u_current_table; +#elif defined(THREADS) + return (struct mapi_table *) ((ThreadSafe) ? + u_tsd_get(&u_current_table_tsd) : (void *) u_current_table); +#else + return u_current_table; +#endif +} |