/*
 * 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.
 */

#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif

#include <string.h>
#include "glxserver.h"
#include <windowstr.h>
#include <propertyst.h>
#include <registry.h>
#include "privates.h"
#include <os.h>
#include "unpack.h"
#include "glxutil.h"
#include "glxext.h"
#include "indirect_table.h"
#include "indirect_util.h"

/*
** The last context used by the server.  It is the context that is current
** from the server's perspective.
*/
__GLXcontext *__glXLastContext;

/*
** X resources.
*/
RESTYPE __glXContextRes;
RESTYPE __glXDrawableRes;

/*
** Reply for most singles.
*/
xGLXSingleReply __glXReply;

static DevPrivateKeyRec glxClientPrivateKeyRec;
#define glxClientPrivateKey (&glxClientPrivateKeyRec)

/*
** Forward declarations.
*/
static int __glXDispatch(ClientPtr);

/*
** Called when the extension is reset.
*/
static void ResetExtension(ExtensionEntry* extEntry)
{
    __glXFlushContextCache();
}

/*
** Reset state used to keep track of large (multi-request) commands.
*/
void __glXResetLargeCommandStatus(__GLXclientState *cl)
{
    cl->largeCmdBytesSoFar = 0;
    cl->largeCmdBytesTotal = 0;
    cl->largeCmdRequestsSoFar = 0;
    cl->largeCmdRequestsTotal = 0;
}

/*
** This procedure is called when the client who created the context goes
** away OR when glXDestroyContext is called.  In either case, all we do is
** flag that the ID is no longer valid, and (maybe) free the context.
** use.
*/
static int ContextGone(__GLXcontext* cx, XID id)
{
    cx->idExists = GL_FALSE;
    if (!cx->isCurrent) {
	__glXFreeContext(cx);
    }

    return True;
}

static __GLXcontext *glxPendingDestroyContexts;
static __GLXcontext *glxAllContexts;
static int glxServerLeaveCount;
static int glxBlockClients;

/*
** Destroy routine that gets called when a drawable is freed.  A drawable
** contains the ancillary buffers needed for rendering.
*/
static Bool DrawableGone(__GLXdrawable *glxPriv, XID xid)
{
    __GLXcontext *c, *next;

    if (glxPriv->type == GLX_DRAWABLE_WINDOW) {
        /* If this was created by glXCreateWindow, free the matching resource */
        if (glxPriv->drawId != glxPriv->pDraw->id) {
            if (xid == glxPriv->drawId)
                FreeResourceByType(glxPriv->pDraw->id, __glXDrawableRes, TRUE);
            else
                FreeResourceByType(glxPriv->drawId, __glXDrawableRes, TRUE);
        }
        /* otherwise this window was implicitly created by MakeCurrent */
    }

    for (c = glxAllContexts; c; c = next) {
	next = c->next;
	if (c->isCurrent && (c->drawPriv == glxPriv || c->readPriv == glxPriv)) {
	    (*c->loseCurrent)(c);
	    c->isCurrent = GL_FALSE;
	    if (c == __glXLastContext)
		__glXFlushContextCache();
	}
	if (c->drawPriv == glxPriv)
	    c->drawPriv = NULL;
	if (c->readPriv == glxPriv)
	    c->readPriv = NULL;
    }

    /* drop our reference to any backing pixmap */
    if (glxPriv->type == GLX_DRAWABLE_PIXMAP)
        glxPriv->pDraw->pScreen->DestroyPixmap((PixmapPtr)glxPriv->pDraw);

    glxPriv->destroy(glxPriv);

    return True;
}

void __glXAddToContextList(__GLXcontext *cx)
{
    cx->next = glxAllContexts;
    glxAllContexts = cx;
}

static void __glXRemoveFromContextList(__GLXcontext *cx)
{
    __GLXcontext *c, *prev;

    if (cx == glxAllContexts)
	glxAllContexts = cx->next;
    else {
	prev = glxAllContexts;
	for (c = glxAllContexts; c; c = c->next) {
	    if (c == cx)
		prev->next = c->next;
	    prev = c;
	}
    }
}

/*
** Free a context.
*/
GLboolean __glXFreeContext(__GLXcontext *cx)
{
    if (cx->idExists || cx->isCurrent) return GL_FALSE;
    
    free(cx->feedbackBuf);
    free(cx->selectBuf);
    if (cx == __glXLastContext) {
	__glXFlushContextCache();
    }

    __glXRemoveFromContextList(cx);

    /* We can get here through both regular dispatching from
     * __glXDispatch() or as a callback from the resource manager.  In
     * the latter case we need to lift the DRI lock manually. */

    if (!glxBlockClients) {
	__glXleaveServer(GL_FALSE);
	cx->destroy(cx);
	__glXenterServer(GL_FALSE);
    } else {
	cx->next = glxPendingDestroyContexts;
	glxPendingDestroyContexts = cx;
    }

    return GL_TRUE;
}

/************************************************************************/

/*
** These routines can be used to check whether a particular GL command
** has caused an error.  Specifically, we use them to check whether a
** given query has caused an error, in which case a zero-length data
** reply is sent to the client.
*/

static GLboolean errorOccured = GL_FALSE;

/*
** The GL was will call this routine if an error occurs.
*/
void __glXErrorCallBack(GLenum code)
{
    errorOccured = GL_TRUE;
}

/*
** Clear the error flag before calling the GL command.
*/
void __glXClearErrorOccured(void)
{
    errorOccured = GL_FALSE;
}

/*
** Check if the GL command caused an error.
*/
GLboolean __glXErrorOccured(void)
{
    return errorOccured;
}

static int __glXErrorBase;
int __glXEventBase;

int __glXError(int error)
{
    return __glXErrorBase + error;
}

__GLXclientState *
glxGetClient(ClientPtr pClient)
{
    return dixLookupPrivate(&pClient->devPrivates, glxClientPrivateKey);
}

static void
glxClientCallback (CallbackListPtr	*list,
		   pointer		closure,
		   pointer		data)
{
    NewClientInfoRec	*clientinfo = (NewClientInfoRec *) data;
    ClientPtr		pClient = clientinfo->client;
    __GLXclientState	*cl = glxGetClient(pClient);

    switch (pClient->clientState) {
    case ClientStateRunning:
	/*
	** By default, assume that the client supports
	** GLX major version 1 minor version 0 protocol.
	*/
	cl->GLClientmajorVersion = 1;
	cl->GLClientminorVersion = 0;
	cl->client = pClient;
	break;

    case ClientStateGone:
	free(cl->returnBuf);
	free(cl->largeCmdBuf);
	free(cl->GLClientextensions);
	break;

    default:
	break;
    }
}

/************************************************************************/

static __GLXprovider *__glXProviderStack;

void GlxPushProvider(__GLXprovider *provider)
{
    provider->next = __glXProviderStack;
    __glXProviderStack = provider;
}

/*
** Initialize the GLX extension.
*/
void GlxExtensionInit(void)
{
    ExtensionEntry *extEntry;
    ScreenPtr pScreen;
    int i;
    __GLXprovider *p;
    Bool glx_provided = False;

    __glXContextRes = CreateNewResourceType((DeleteType)ContextGone,
					    "GLXContext");
    __glXDrawableRes = CreateNewResourceType((DeleteType)DrawableGone,
					     "GLXDrawable");
    if (!__glXContextRes || !__glXDrawableRes)
	return;

    if (!dixRegisterPrivateKey(&glxClientPrivateKeyRec, PRIVATE_CLIENT, sizeof (__GLXclientState)))
	return;
    if (!AddCallback (&ClientStateCallback, glxClientCallback, 0))
	return;

    for (i = 0; i < screenInfo.numScreens; i++) {
	pScreen = screenInfo.screens[i];

	for (p = __glXProviderStack; p != NULL; p = p->next) {
	    __GLXscreen *glxScreen;

	    glxScreen = p->screenProbe(pScreen);
	    if (glxScreen != NULL) {
	        if (glxScreen->GLXminor < glxMinorVersion)
		    glxMinorVersion = glxScreen->GLXminor;
		LogMessage(X_INFO,
			   "GLX: Initialized %s GL provider for screen %d\n",
			   p->name, i);
		break;
	    }

	}

	if (!p)
	    LogMessage(X_INFO,
		       "GLX: no usable GL providers found for screen %d\n", i);
	else
	    glx_provided = True;
    }

    /* don't register extension if GL is not provided on any screen */
    if (!glx_provided)
	return;

    /*
    ** Add extension to server extensions.
    */
    extEntry = AddExtension(GLX_EXTENSION_NAME, __GLX_NUMBER_EVENTS,
			    __GLX_NUMBER_ERRORS, __glXDispatch,
			    __glXDispatch, ResetExtension,
			    StandardMinorOpcode);
    if (!extEntry) {
	FatalError("__glXExtensionInit: AddExtensions failed\n");
	return;
    }
    if (!AddExtensionAlias(GLX_EXTENSION_ALIAS, extEntry)) {
	ErrorF("__glXExtensionInit: AddExtensionAlias failed\n");
	return;
    }

    __glXErrorBase = extEntry->errorBase;
    __glXEventBase = extEntry->eventBase;
}

/************************************************************************/

void __glXFlushContextCache(void)
{
    __glXLastContext = 0;
}

/*
** Make a context the current one for the GL (in this implementation, there
** is only one instance of the GL, and we use it to serve all GL clients by
** switching it between different contexts).  While we are at it, look up
** a context by its tag and return its (__GLXcontext *).
*/
__GLXcontext *__glXForceCurrent(__GLXclientState *cl, GLXContextTag tag,
				int *error)
{
    __GLXcontext *cx;

    /*
    ** See if the context tag is legal; it is managed by the extension,
    ** so if it's invalid, we have an implementation error.
    */
    cx = __glXLookupContextByTag(cl, tag);
    if (!cx) {
	cl->client->errorValue = tag;
	*error = __glXError(GLXBadContextTag);
	return 0;
    }

    if (!cx->isDirect) {
	if (cx->drawPriv == NULL) {
	    /*
	    ** The drawable has vanished.  It must be a window, because only
	    ** windows can be destroyed from under us; GLX pixmaps are
	    ** refcounted and don't go away until no one is using them.
	    */
	    *error = __glXError(GLXBadCurrentWindow);
	    return 0;
    	}
    }
    
    if (cx->wait && (*cx->wait)(cx, cl, error))
	return NULL;

    if (cx == __glXLastContext) {
	/* No need to re-bind */
	return cx;
    }

    /* Make this context the current one for the GL. */
    if (!cx->isDirect) {
	if (!(*cx->makeCurrent)(cx)) {
	    /* Bind failed, and set the error code.  Bummer */
	    cl->client->errorValue = cx->id;
	    *error = __glXError(GLXBadContextState);
	    return 0;
    	}
    }
    __glXLastContext = cx;
    return cx;
}

/************************************************************************/

void glxSuspendClients(void)
{
    int i;

    for (i = 1; i < currentMaxClients; i++) {
	if (clients[i] && glxGetClient(clients[i])->inUse)
	    IgnoreClient(clients[i]);
    }

    glxBlockClients = TRUE;
}

void glxResumeClients(void)
{
    __GLXcontext *cx, *next;
    int i;

    glxBlockClients = FALSE;

    for (i = 1; i < currentMaxClients; i++) {
	if (clients[i] && glxGetClient(clients[i])->inUse)
	    AttendClient(clients[i]);
    }

    __glXleaveServer(GL_FALSE);
    for (cx = glxPendingDestroyContexts; cx != NULL; cx = next) {
	next = cx->next;

	cx->destroy(cx);
    }
    glxPendingDestroyContexts = NULL;
    __glXenterServer(GL_FALSE);
}

static void
__glXnopEnterServer(GLboolean rendering)
{
}
    
static void
__glXnopLeaveServer(GLboolean rendering)
{
}

static void (*__glXenterServerFunc)(GLboolean) = __glXnopEnterServer;
static void (*__glXleaveServerFunc)(GLboolean)  = __glXnopLeaveServer;

void __glXsetEnterLeaveServerFuncs(void (*enter)(GLboolean),
				   void (*leave)(GLboolean))
{
  __glXenterServerFunc = enter;
  __glXleaveServerFunc = leave;
}


void __glXenterServer(GLboolean rendering)
{
  glxServerLeaveCount--;

  if (glxServerLeaveCount == 0)
    (*__glXenterServerFunc)(rendering);
}

void __glXleaveServer(GLboolean rendering)
{
  if (glxServerLeaveCount == 0)
    (*__glXleaveServerFunc)(rendering);

  glxServerLeaveCount++;
}

/*
** Top level dispatcher; all commands are executed from here down.
*/
static int __glXDispatch(ClientPtr client)
{
    REQUEST(xGLXSingleReq);
    CARD8 opcode;
    __GLXdispatchSingleProcPtr proc;
    __GLXclientState *cl;
    int retval;

    opcode = stuff->glxCode;
    cl = glxGetClient(client);
    /* Mark it in use so we suspend it on VT switch. */
    cl->inUse = TRUE;

    /*
    ** If we're expecting a glXRenderLarge request, this better be one.
    */
    if ((cl->largeCmdRequestsSoFar != 0) && (opcode != X_GLXRenderLarge)) {
	client->errorValue = stuff->glxCode;
	return __glXError(GLXBadLargeRequest);
    }

    /* If we're currently blocking GLX clients, just put this guy to
     * sleep, reset the request and return. */
    if (glxBlockClients) {
	ResetCurrentRequest(client);
	client->sequence--;
	IgnoreClient(client);
	return Success;
    }

    /*
    ** Use the opcode to index into the procedure table.
    */
    proc = __glXGetProtocolDecodeFunction(& Single_dispatch_info, opcode,
                                          client->swapped);
    if (proc != NULL) {
	GLboolean rendering = opcode <= X_GLXRenderLarge;
	__glXleaveServer(rendering);

	retval = (*proc)(cl, (GLbyte *) stuff);

	__glXenterServer(rendering);
    }
    else {
	retval = BadRequest;
    }

    return retval;
}
