1/* 2 * Mesa 3-D graphics library 3 * 4 * Copyright (C) 1999-2008 Brian Paul All Rights Reserved. 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the "Software"), 8 * to deal in the Software without restriction, including without limitation 9 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 10 * and/or sell copies of the Software, and to permit persons to whom the 11 * Software is furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included 14 * in all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 20 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 21 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 22 * OTHER DEALINGS IN THE SOFTWARE. 23 */ 24 25 26/* 27 * This file manages the OpenGL API dispatch layer. 28 * The dispatch table (struct _glapi_table) is basically just a list 29 * of function pointers. 30 * There are functions to set/get the current dispatch table for the 31 * current thread and to manage registration/dispatch of dynamically 32 * added extension functions. 33 * 34 * It's intended that this file and the other glapi*.[ch] files are 35 * flexible enough to be reused in several places: XFree86, DRI- 36 * based libGL.so, and perhaps the SGI SI. 37 * 38 * NOTE: There are no dependencies on Mesa in this code. 39 * 40 * Versions (API changes): 41 * 2000/02/23 - original version for Mesa 3.3 and XFree86 4.0 42 * 2001/01/16 - added dispatch override feature for Mesa 3.5 43 * 2002/06/28 - added _glapi_set_warning_func(), Mesa 4.1. 44 * 2002/10/01 - _glapi_get_proc_address() will now generate new entrypoints 45 * itself (using offset ~0). _glapi_add_entrypoint() can be 46 * called afterward and it'll fill in the correct dispatch 47 * offset. This allows DRI libGL to avoid probing for DRI 48 * drivers! No changes to the public glapi interface. 49 */ 50 51#include "c11/threads.h" 52#include "util/u_thread.h" 53#include "u_current.h" 54 55#ifndef MAPI_MODE_UTIL 56 57#include "table.h" 58#include "stub.h" 59 60#else 61 62extern void init_glapi_relocs_once(void); 63extern void (*__glapi_noop_table[])(void); 64 65#define table_noop_array __glapi_noop_table 66#define stub_init_once() init_glapi_relocs_once() 67 68#endif 69 70/** 71 * \name Current dispatch and current context control variables 72 * 73 * Depending on whether or not multithreading is support, and the type of 74 * support available, several variables are used to store the current context 75 * pointer and the current dispatch table pointer. In the non-threaded case, 76 * the variables \c _glapi_Dispatch and \c _glapi_Context are used for this 77 * purpose. 78 * 79 * In the "normal" threaded case, the variables \c _glapi_Dispatch and 80 * \c _glapi_Context will be \c NULL if an application is detected as being 81 * multithreaded. Single-threaded applications will use \c _glapi_Dispatch 82 * and \c _glapi_Context just like the case without any threading support. 83 * When \c _glapi_Dispatch and \c _glapi_Context are \c NULL, the thread state 84 * data \c _gl_DispatchTSD and \c ContextTSD are used. Drivers and the 85 * static dispatch functions access these variables via \c _glapi_get_dispatch 86 * and \c _glapi_get_context. 87 * 88 * 89 * In the TLS case, the variables \c _glapi_Dispatch and \c _glapi_Context are 90 * hardcoded to \c NULL. Instead the TLS variables \c _glapi_tls_Dispatch and 91 * \c _glapi_tls_Context are used. Having \c _glapi_Dispatch and 92 * \c _glapi_Context be hardcoded to \c NULL maintains binary compatability 93 * between TLS enabled loaders and non-TLS DRI drivers. 94 */ 95/*@{*/ 96 97__THREAD_INITIAL_EXEC struct _glapi_table *u_current_table 98 = (struct _glapi_table *) table_noop_array; 99 100__THREAD_INITIAL_EXEC void *u_current_context; 101 102/*@}*/ 103 104/** 105 * Set the current context pointer for this thread. 106 * The context pointer is an opaque type which should be cast to 107 * void from the real context pointer type. 108 */ 109void 110u_current_set_context(const void *ptr) 111{ 112 u_current_context = (void *) ptr; 113} 114 115/** 116 * Get the current context pointer for this thread. 117 * The context pointer is an opaque type which should be cast from 118 * void to the real context pointer type. 119 */ 120void * 121u_current_get_context_internal(void) 122{ 123 return u_current_context; 124} 125 126/** 127 * Set the global or per-thread dispatch table pointer. 128 * If the dispatch parameter is NULL we'll plug in the no-op dispatch 129 * table (__glapi_noop_table). 130 */ 131void 132u_current_set_table(const struct _glapi_table *tbl) 133{ 134 stub_init_once(); 135 136 if (!tbl) 137 tbl = (const struct _glapi_table *) table_noop_array; 138 139 u_current_table = (struct _glapi_table *) tbl; 140} 141 142/** 143 * Return pointer to current dispatch table for calling thread. 144 */ 145struct _glapi_table * 146u_current_get_table_internal(void) 147{ 148 return u_current_table; 149} 150