/*
 * 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 "extinit.h"
#include "glx_extinit.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;
}

Bool
__glXAddContext(__GLXcontext * cx)
{
    /* Register this context as a resource.
     */
    if (!AddResource(cx->id, __glXContextRes, (pointer)cx)) {
	return False;
    }

    cx->next = glxAllContexts;
    glxAllContexts = cx;
    return True;
}

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->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, **stack;
    Bool glx_provided = False;

    if (serverGeneration == 1) {
        for (stack = &__glXProviderStack; *stack; stack = &(*stack)->next)
            ;
        *stack = &__glXDRISWRastProvider;
    }

    __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;
}