resource.c

远程桌面连接工具

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

Copyright (c) 1987  X Consortium

Permission is hereby granted, free of charge, to any person obtaining a copy
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all copies or substantial portions of the Software.

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in this Software without prior written authorization from the X Consortium.


Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in 
supporting documentation, and that the name of Digital not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.  

DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
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********************************************************/

/* $XConsortium: resource.c /main/39 1996/10/30 11:17:56 rws $ */
/* $XFree86: xc/programs/Xserver/dix/resource.c,v 3.1 1996/12/23 06:29:51 dawes Exp $ */

/*	Routines to manage various kinds of resources:
 *
 *	CreateNewResourceType, CreateNewResourceClass, InitClientResources,
 *	FakeClientID, AddResource, FreeResource, FreeClientResources,
 *	FreeAllResources, LookupIDByType, LookupIDByClass, GetXIDRange
 */

/* 
 *      A resource ID is a 32 bit quantity, the upper 3 bits of which are
 *	off-limits for client-visible resources.  The next 7 bits are
 *      used as client ID, and the low 22 bits come from the client.
 *	A resource ID is "hashed" by extracting and xoring subfields
 *      (varying with the size of the hash table).
 *
 *      It is sometimes necessary for the server to create an ID that looks
 *      like it belongs to a client.  This ID, however,  must not be one
 *      the client actually can create, or we have the potential for conflict.
 *      The 30th bit of the ID is reserved for the server's use for this
 *      purpose.  By setting CLIENT_ID(id) to the client, the SERVER_BIT to
 *      1, and an otherwise arbitrary ID in the low 22 bits, we can create a
 *      resource "owned" by the client.
 */

#define NEED_EVENTS
#include "X.h"
#include "misc.h"
#include "os.h"
#include "resource.h"
#include "dixstruct.h" 
#include "opaque.h"
#include "windowstr.h"
#include "inputstr.h"
#include "dixfont.h"
#include "dixevents.h"
#include "dixgrabs.h"
#include "colormap.h"
#include "cursor.h"
#include <assert.h>

extern WindowPtr *WindowTable;

static void RebuildTable(
#if NeedFunctionPrototypes
    int /*client*/
#endif
);

#define SERVER_MINID 32

#define INITBUCKETS 64
#define INITHASHSIZE 6
#define MAXHASHSIZE 11

typedef struct _Resource {
    struct _Resource	*next;
    XID			id;
    RESTYPE		type;
    pointer		value;
} ResourceRec, *ResourcePtr;
#define NullResource ((ResourcePtr)NULL)

typedef struct _ClientResource {
    ResourcePtr *resources;
    int		elements;
    int		buckets;
    int		hashsize;	/* log(2)(buckets) */
    XID		fakeID;
    XID		endFakeID;
    XID		expectID;
} ClientResourceRec;

static RESTYPE lastResourceType;
static RESTYPE lastResourceClass;
static RESTYPE TypeMask;

static DeleteType *DeleteFuncs = (DeleteType *)NULL;

RESTYPE
CreateNewResourceType(deleteFunc)
    DeleteType deleteFunc;
{
    RESTYPE next = lastResourceType + 1;
    DeleteType *funcs;

    if (next & lastResourceClass)
	return 0;
    funcs = (DeleteType *)xrealloc(DeleteFuncs,
				   (next + 1) * sizeof(DeleteType));
    if (!funcs)
	return 0;
    lastResourceType = next;
    DeleteFuncs = funcs;
    DeleteFuncs[next] = deleteFunc;
    return next;
}

RESTYPE
CreateNewResourceClass()
{
    RESTYPE next = lastResourceClass >> 1;

    if (next & lastResourceType)
	return 0;
    lastResourceClass = next;
    TypeMask = next - 1;
    return next;
}

ClientResourceRec clientTable[MAXCLIENTS];

/*****************
 * InitClientResources
 *    When a new client is created, call this to allocate space
 *    in resource table
 *****************/

Bool
InitClientResources(client)
    ClientPtr client;
{
    register int i, j;
 
    if (client == serverClient)
    {
	lastResourceType = RT_LASTPREDEF;
	lastResourceClass = RC_LASTPREDEF;
	TypeMask = RC_LASTPREDEF - 1;
	if (DeleteFuncs)
	    xfree(DeleteFuncs);
	DeleteFuncs = (DeleteType *)xalloc((lastResourceType + 1) *
					   sizeof(DeleteType));
	if (!DeleteFuncs)
	    return FALSE;
	DeleteFuncs[RT_NONE & TypeMask] = (DeleteType)NoopDDA;
	DeleteFuncs[RT_WINDOW & TypeMask] = DeleteWindow;
	DeleteFuncs[RT_PIXMAP & TypeMask] = dixDestroyPixmap;
	DeleteFuncs[RT_GC & TypeMask] = FreeGC;
	DeleteFuncs[RT_FONT & TypeMask] = CloseFont;
	DeleteFuncs[RT_CURSOR & TypeMask] = FreeCursor;
	DeleteFuncs[RT_COLORMAP & TypeMask] = FreeColormap;
	DeleteFuncs[RT_CMAPENTRY & TypeMask] = FreeClientPixels;
	DeleteFuncs[RT_OTHERCLIENT & TypeMask] = OtherClientGone;
	DeleteFuncs[RT_PASSIVEGRAB & TypeMask] = DeletePassiveGrab;
    }
    clientTable[i = client->index].resources =
	(ResourcePtr *)xalloc(INITBUCKETS*sizeof(ResourcePtr));
    if (!clientTable[i].resources)
	return FALSE;
    clientTable[i].buckets = INITBUCKETS;
    clientTable[i].elements = 0;
    clientTable[i].hashsize = INITHASHSIZE;
    /* Many IDs allocated from the server client are visible to clients,
     * so we don't use the SERVER_BIT for them, but we have to start
     * past the magic value constants used in the protocol.  For normal
     * clients, we can start from zero, with SERVER_BIT set.
     */
    clientTable[i].fakeID = client->clientAsMask |
			    (client->index ? SERVER_BIT : SERVER_MINID);
    clientTable[i].endFakeID = (clientTable[i].fakeID | RESOURCE_ID_MASK) + 1;
    clientTable[i].expectID = client->clientAsMask;
    for (j=0; j<INITBUCKETS; j++) 
    {
        clientTable[i].resources[j] = NullResource;
    }
    return TRUE;
}

static int
#if NeedFunctionPrototypes
Hash(int client, register XID id)
#else
Hash(client, id)
    int client;
    register XID id;
#endif
{
    id &= RESOURCE_ID_MASK;
    switch (clientTable[client].hashsize)
    {
	case 6:
	    return ((int)(0x03F & (id ^ (id>>6) ^ (id>>12))));
	case 7:
	    return ((int)(0x07F & (id ^ (id>>7) ^ (id>>13))));
	case 8:
	    return ((int)(0x0FF & (id ^ (id>>8) ^ (id>>16))));
	case 9:
	    return ((int)(0x1FF & (id ^ (id>>9))));
	case 10:
	    return ((int)(0x3FF & (id ^ (id>>10))));
	case 11:
	    return ((int)(0x7FF & (id ^ (id>>11))));
    }
    return -1;
}

static XID
#if NeedFunctionPrototypes
AvailableID(
    register int client,
    register XID id,
    register XID maxid,
    register XID goodid)
#else
AvailableID(client, id, maxid, goodid)
    register int client;
    register XID id, maxid, goodid;
#endif
{
    register ResourcePtr res;

    if ((goodid >= id) && (goodid <= maxid))
	return goodid;
    for (; id <= maxid; id++)
    {
	res = clientTable[client].resources[Hash(client, id)];
	while (res && (res->id != id))
	    res = res->next;
	if (!res)
	    return id;
    }
    return 0;
}

void
GetXIDRange(client, server, minp, maxp)
    int client;
    Bool server;
    XID *minp, *maxp;
{
    register XID id, maxid;
    register ResourcePtr *resp;
    register ResourcePtr res;
    register int i;
    XID goodid;

    id = (Mask)client << CLIENTOFFSET;
    if (server)
	id |= client ? SERVER_BIT : SERVER_MINID;
    maxid = id | RESOURCE_ID_MASK;
    goodid = 0;
    for (resp = clientTable[client].resources, i = clientTable[client].buckets;
	 --i >= 0;)
    {
	for (res = *resp++; res; res = res->next)
	{
	    if ((res->id < id) || (res->id > maxid))
		continue;
	    if (((res->id - id) >= (maxid - res->id)) ?
		(goodid = AvailableID(client, id, res->id - 1, goodid)) :
		!(goodid = AvailableID(client, res->id + 1, maxid, goodid)))
		maxid = res->id - 1;
	    else
		id = res->id + 1;
	}
    }
    if (id > maxid)
	id = maxid = 0;
    *minp = id;
    *maxp = maxid;
}

/*  GetXIDList is called by the XC-MISC extension's MiscGetXIDList function.
 *  This function tries to find count unused XIDs for the given client.  It 
 *  puts the IDs in the array pids and returns the number found, which should
 *  almost always be the number requested.
 *
 *  The circumstances that lead to a call to this function are very rare.
 *  Xlib must run out of IDs while trying to generate a request that wants
 *  multiple ID's, like the Multi-buffering CreateImageBuffers request.
 *
 *  No rocket science in the implementation; just iterate over all
 *  possible IDs for the given client and pick the first count IDs
 *  that aren't in use.  A more efficient algorithm could probably be
 *  invented, but this will be used so rarely that this should suffice.
 */

unsigned int
GetXIDList(pClient, count, pids)
    ClientPtr pClient;
    unsigned int count;
    XID *pids;
{
    unsigned int found = 0;
    XID id = pClient->clientAsMask;
    XID maxid;

    maxid = id | RESOURCE_ID_MASK;
    while ( (found < count) && (id <= maxid) )
    {
	if (!LookupIDByClass(id, RC_ANY))
	{
	    pids[found++] = id;
	}
	id++;
    }
    return found;
}

/*
 * Return the next usable fake client ID.
 *
 * Normally this is just the next one in line, but if we've used the last
 * in the range, we need to find a new range of safe IDs to avoid
 * over-running another client.
 */

XID
FakeClientID(client)
    register int client;
{
    XID id, maxid;

    id = clientTable[client].fakeID++;
    if (id != clientTable[client].endFakeID)
	return id;
    GetXIDRange(client, TRUE, &id, &maxid);
    if (!id) {
	if (!client)
	    FatalError("FakeClientID: server internal ids exhausted\n");
	MarkClientException(clients[client]);
	id = ((Mask)client << CLIENTOFFSET) | (SERVER_BIT * 3);
	maxid = id | RESOURCE_ID_MASK;
    }
    clientTable[client].fakeID = id + 1;
    clientTable[client].endFakeID = maxid + 1;
    return id;
}

Bool
AddResource(id, type, value)
    XID id;
    RESTYPE type;
    pointer value;
{
    int client;
    register ClientResourceRec *rrec;
    register ResourcePtr res, *head;
    	
    client = CLIENT_ID(id);
    rrec = &clientTable[client];
    if (!rrec->buckets)
    {
	ErrorF("AddResource(%x, %x, %x), client=%d \n",
		id, type, (unsigned long)value, client);
        FatalError("client not in use\n");
    }
    if ((rrec->elements >= 4*rrec->buckets) &&
	(rrec->hashsize < MAXHASHSIZE))
	RebuildTable(client);
    head = &rrec->resources[Hash(client, id)];
    res = (ResourcePtr)xalloc(sizeof(ResourceRec));
    if (!res)
    {
	(*DeleteFuncs[type & TypeMask])(value, id);
	return FALSE;
    }
    res->next = *head;
    res->id = id;
    res->type = type;
    res->value = value;
    *head = res;
    rrec->elements++;
    if (!(id & SERVER_BIT) && (id >= rrec->expectID))
	rrec->expectID = id + 1;
    return TRUE;
}

static void
RebuildTable(client)
    int client;
{
    register int j;
    register ResourcePtr res, next;
    ResourcePtr **tails, *resources;
    register ResourcePtr **tptr, *rptr;

    /*
     * For now, preserve insertion order, since some ddx layers depend
     * on resources being free in the opposite order they are added.
     */

    j = 2 * clientTable[client].buckets;
    tails = (ResourcePtr **)ALLOCATE_LOCAL(j * sizeof(ResourcePtr *));
    if (!tails)
	return;