mesa/src/mapi/u_current.c

150 lines
5.1 KiB
C

/*
* Mesa 3-D graphics library
*
* 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 "c11/threads.h"
#include "util/u_thread.h"
#include "u_current.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.
*
*
* 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.
*/
/*@{*/
__THREAD_INITIAL_EXEC struct _glapi_table *u_current_table
= (struct _glapi_table *) table_noop_array;
__THREAD_INITIAL_EXEC void *u_current_context;
/*@}*/
/**
* 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_context(const void *ptr)
{
u_current_context = (void *) ptr;
}
/**
* 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_context_internal(void)
{
return u_current_context;
}
/**
* 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_table(const struct _glapi_table *tbl)
{
stub_init_once();
if (!tbl)
tbl = (const struct _glapi_table *) table_noop_array;
u_current_table = (struct _glapi_table *) tbl;
}
/**
* Return pointer to current dispatch table for calling thread.
*/
struct _glapi_table *
u_current_get_table_internal(void)
{
return u_current_table;
}