/*
* SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
* Copyright (C) 1991-2000 Silicon Graphics, Inc. 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 including the dates of first publication and
* either this permission notice or a reference to
* http://oss.sgi.com/projects/FreeB/
* 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
* SILICON GRAPHICS, INC. 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.
*
* Except as contained in this notice, the name of Silicon Graphics, Inc.
* shall not be used in advertising or otherwise to promote the sale, use or
* other dealings in this Software without prior written authorization from
* Silicon Graphics, Inc.
*/
/**
* \file glxcurrent.c
* Client-side GLX interface for current context management.
*/
#include <pthread.h>
#include "glxclient.h"
#include "glapi.h"
/*
** We setup some dummy structures here so that the API can be used
** even if no context is current.
*/
static GLubyte dummyBuffer[__GLX_BUFFER_LIMIT_SIZE];
static struct glx_context_vtable dummyVtable;
/*
** Dummy context used by small commands when there is no current context.
** All the
** gl and glx entry points are designed to operate as nop's when using
** the dummy context structure.
*/
struct glx_context dummyContext = {
&dummyBuffer[0],
&dummyBuffer[0],
&dummyBuffer[0],
&dummyBuffer[__GLX_BUFFER_LIMIT_SIZE],
sizeof(dummyBuffer),
&dummyVtable
};
/*
* Current context management and locking
*/
_X_HIDDEN pthread_mutex_t __glXmutex = PTHREAD_MUTEX_INITIALIZER;
# if defined( GLX_USE_TLS )
/**
* Per-thread GLX context pointer.
*
* \c __glXSetCurrentContext is written is such a way that this pointer can
* \b never be \c NULL. This is important! Because of this
* \c __glXGetCurrentContext can be implemented as trivial macro.
*/
__thread void *__glX_tls_Context __attribute__ ((tls_model("initial-exec")))
= &dummyContext;
_X_HIDDEN void
__glXSetCurrentContext(struct glx_context * c)
{
__glX_tls_Context = (c != NULL) ? c : &dummyContext;
}
# else
static pthread_once_t once_control = PTHREAD_ONCE_INIT;
/**
* Per-thread data key.
*
* Once \c init_thread_data has been called, the per-thread data key will
* take a value of \c NULL. As each new thread is created the default
* value, in that thread, will be \c NULL.
*/
static pthread_key_t ContextTSD;
/**
* Initialize the per-thread data key.
*
* This function is called \b exactly once per-process (not per-thread!) to
* initialize the per-thread data key. This is ideally done using the
* \c pthread_once mechanism.
*/
static void
init_thread_data(void)
{
if (pthread_key_create(&ContextTSD, NULL) != 0) {
}
}
_X_HIDDEN void
__glXSetCurrentContext(struct glx_context * c)
{
pthread_once(&once_control, init_thread_data);
pthread_setspecific(ContextTSD, c);
}
_X_HIDDEN struct glx_context *
__glXGetCurrentContext(void)
{
void *v;
pthread_once(&once_control, init_thread_data);
v = pthread_getspecific(ContextTSD);
return (v == NULL) ? &dummyContext : (struct glx_context *) v;
}
# endif /* defined( GLX_USE_TLS ) */
_X_HIDDEN void
__glXSetCurrentContextNull(void)
{
__glXSetCurrentContext(&dummyContext);
#if defined(GLX_DIRECT_RENDERING)
_glapi_set_dispatch(NULL); /* no-op functions */
_glapi_set_context(NULL);
#endif
}
_X_EXPORT GLXContext
glXGetCurrentContext(void)
{
struct glx_context *cx = __glXGetCurrentContext();
if (cx == &dummyContext) {
return NULL;
}
else {
return (GLXContext) cx;
}
}
_X_EXPORT GLXDrawable
glXGetCurrentDrawable(void)
{
struct glx_context *gc = __glXGetCurrentContext();
return gc->currentDrawable;
}
static void
__glXGenerateError(Display * dpy, XID resource,
BYTE errorCode, CARD16 minorCode)
{
xError error;
error.errorCode = errorCode;
error.resourceID = resource;
error.sequenceNumber = dpy->request;
error.type = X_Error;
error.majorCode = __glXSetupForCommand(dpy);
error.minorCode = minorCode;
_XError(dpy, &error);
}
/**
* Make a particular context current.
*
* \note This is in this file so that it can access dummyContext.
*/
static Bool
MakeContextCurrent(Display * dpy, GLXDrawable draw,
GLXDrawable read, GLXContext gc_user)
{
struct glx_context *gc = (struct glx_context *) gc_user;
struct glx_context *oldGC = __glXGetCurrentContext();
/* Make sure that the new context has a nonzero ID. In the request,
* a zero context ID is used only to mean that we bind to no current
* context.
*/
if ((gc != NULL) && (gc->xid == None)) {
return GL_FALSE;
}
_glapi_check_multithread();
__glXLock();
if (oldGC == gc &&
gc->currentDrawable == draw && gc->currentReadable == read) {
__glXUnlock();
return True;
}
if (oldGC != &dummyContext) {
if (--oldGC->thread_refcount == 0) {
oldGC->vtable->unbind(oldGC, gc);
oldGC->currentDpy = 0;
}
}
if (gc) {
/* Attempt to bind the context. We do this before mucking with
* gc and __glXSetCurrentContext to properly handle our state in
* case of an error.
*
* If an error occurs, set the Null context since we've already
* blown away our old context. The caller is responsible for
* figuring out how to handle setting a valid context.
*/
if (gc->vtable->bind(gc, oldGC, draw, read) != Success) {
__glXSetCurrentContextNull();
__glXUnlock();
__glXGenerateError(dpy, None, GLXBadContext, X_GLXMakeContextCurrent);
return GL_FALSE;
}
if (gc->thread_refcount == 0) {
gc->currentDpy = dpy;
gc->currentDrawable = draw;
gc->currentReadable = read;
}
gc->thread_refcount++;
__glXSetCurrentContext(gc);
} else {
__glXSetCurrentContextNull();
}
if (oldGC->thread_refcount == 0 && oldGC != &dummyContext && oldGC->xid == None) {
/* We are switching away from a context that was
* previously destroyed, so we need to free the memory
* for the old handle. */
oldGC->vtable->destroy(oldGC);
}
__glXUnlock();
return GL_TRUE;
}
_X_EXPORT Bool
glXMakeCurrent(Display * dpy, GLXDrawable draw, GLXContext gc)
{
return MakeContextCurrent(dpy, draw, draw, gc);
}
_X_EXPORT
GLX_ALIAS(Bool, glXMakeCurrentReadSGI,
(Display * dpy, GLXDrawable d, GLXDrawable r, GLXContext ctx),
(dpy, d, r, ctx), MakeContextCurrent)
_X_EXPORT
GLX_ALIAS(Bool, glXMakeContextCurrent,
(Display * dpy, GLXDrawable d, GLXDrawable r,
GLXContext ctx), (dpy, d, r, ctx), MakeContextCurrent)