path: root/generic/tkOption.c

/*
 * tkOption.c --
 *
 *	This module contains functions to manage the option database, which
 *	allows various strings to be associated with windows either by name or
 *	by class or both.
 *
 * Copyright (c) 1990-1994 The Regents of the University of California.
 * Copyright (c) 1994-1997 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 */

#include "tkInt.h"

/*
 * The option database is stored as one tree for each main window. Each name
 * or class field in an option is associated with a node or leaf of the tree.
 * For example, the options "x.y.z" and "x.y*a" each correspond to three nodes
 * in the tree; they share the nodes "x" and "x.y", but have different leaf
 * nodes. One of the following structures exists for each node or leaf in the
 * option tree. It is actually stored as part of the parent node, and
 * describes a particular child of the parent.
 *
 * The structure of the option db tree is a little confusing. There are four
 * different kinds of nodes in the tree:
 *	interior class nodes
 *	interior name nodes
 *	leaf class nodes
 *	leaf name nodes
 *
 * All interior nodes refer to _window_ classes and names; all leaf nodes
 * refer to _option_ classes and names. When looking for a particular option,
 * therefore, you must compare interior node values to corresponding window
 * values, and compare leaf node values to corresponding option values.
 *
 * The tree is actually stored in a collection of arrays; there is one each
 * combination of WILDCARD/EXACT and CLASS/NAME and NODE/LEAF. The NODE arrays
 * contain the interior nodes of the tree; each element has a pointer to an
 * array of elements which are the leaves of the tree. The LEAF arrays, rather
 * than holding the leaves of the tree, hold a cached subset of the option
 * database, consisting of the values of all defined options for a single
 * window, and some additional information about each ancestor of the window
 * (since some options may be inherited from a parent), all the way back to
 * the root window.
 *
 * Each time a call is made to Tk_GetOption, Tk will attempt to use the cached
 * information to satisfy the lookup. If the call is for a window other than
 * that for which options are currently cached, the portion of the cache that
 * contains information for common ancestors of the two windows is retained
 * and the remainder is discarded and rebuilt with new information for the new
 * window.
 */

typedef struct Element {
    Tk_Uid nameUid;		/* Name or class from one element of an option
				 * spec. */
    union {
	struct ElArray *arrayPtr;
				/* If this is an intermediate node, a pointer
				 * to a structure describing the remaining
				 * elements of all options whose prefixes are
				 * the same up through this element. */
	Tk_Uid valueUid;	/* For leaf nodes, this is the string value of
				 * the option. */
    } child;
    int priority;		/* Used to select among matching options.
				 * Includes both the priority level and a
				 * serial #. Greater value means higher
				 * priority. Irrelevant except in leaf
				 * nodes. */
    int flags;			/* OR-ed combination of bits. See below for
				 * values. */
} Element;

/*
 * Flags in Element structures:
 *
 * CLASS -		Non-zero means this element refers to a class, zero
 *			means this element refers to a name.
 * NODE -		Zero means this is a leaf element (the child field is
 *			a value, not a pointer to another node). One means
 *			this is a node element.
 * WILDCARD -		Non-zero means this there was a star in the original
 *			specification just before this element. Zero means
 *			there was a dot.
 */

#define TYPE_MASK		0x7

#define CLASS			0x1
#define NODE			0x2
#define WILDCARD		0x4

#define EXACT_LEAF_NAME		0x0
#define EXACT_LEAF_CLASS	0x1
#define EXACT_NODE_NAME		0x2
#define EXACT_NODE_CLASS	0x3
#define WILDCARD_LEAF_NAME	0x4
#define WILDCARD_LEAF_CLASS	0x5
#define WILDCARD_NODE_NAME	0x6
#define WILDCARD_NODE_CLASS	0x7

/*
 * The following structure is used to manage a dynamic array of Elements.
 * These structures are used for two purposes: to store the contents of a node
 * in the option tree, and for the option stacks described below.
 */

typedef struct ElArray {
    int arraySize;		/* Number of elements actually allocated in
				 * the "els" array. */
    int numUsed;		/* Number of elements currently in use out of
				 * els. */
    Element *nextToUse;		/* Pointer to &els[numUsed]. */
    Element els[1];		/* Array of structures describing children of
				 * this node. The array will actually contain
				 * enough elements for all of the children
				 * (and even a few extras, perhaps). This must
				 * be the last field in the structure. */
} ElArray;

#define EL_ARRAY_SIZE(numEls) ((unsigned) (sizeof(ElArray) \
	+ ((numEls)-1)*sizeof(Element)))
#define INITIAL_SIZE 5

/*
 * In addition to the option tree, which is a relatively static structure,
 * there are eight additional structures called "stacks", which are used to
 * speed up queries into the option database. The stack structures are
 * designed for the situation where an individual widget makes repeated
 * requests for its particular options. The requests differ only in their last
 * name/class, so during the first request we extract all the options
 * pertaining to the particular widget and save them in a stack-like cache;
 * subsequent requests for the same widget can search the cache relatively
 * quickly. In fact, the cache is a hierarchical one, storing a list of
 * relevant options for this widget and all of its ancestors up to the
 * application root; hence the name "stack".
 *
 * Each of the eight stacks consists of an array of Elements, ordered in terms
 * of levels in the window hierarchy. All the elements relevant for the
 * top-level widget appear first in the array, followed by all those from the
 * next-level widget on the path to the current widget, etc. down to those for
 * the current widget.
 *
 * Cached information is divided into eight stacks according to the CLASS,
 * NODE, and WILDCARD flags. Leaf and non-leaf information is kept separate to
 * speed up individual probes (non-leaf information is only relevant when
 * building the stacks, but isn't relevant when making probes; similarly, only
 * non-leaf information is relevant when the stacks are being extended to the
 * next widget down in the widget hierarchy). Wildcard elements are handled
 * separately from "exact" elements because once they appear at a particular
 * level in the stack they remain active for all deeper levels; exact elements
 * are only relevant at a particular level. For example, when searching for
 * options relevant in a particular window, the entire wildcard stacks get
 * checked, but only the portions of the exact stacks that pertain to the
 * window's parent. Lastly, name and class stacks are kept separate because
 * different search keys are used when searching them; keeping them separate
 * speeds up the searches.
 */

#define NUM_STACKS 8

/*
 * One of the following structures is used to keep track of each level in the
 * stacks.
 */

typedef struct StackLevel {
    TkWindow *winPtr;		/* Window corresponding to this stack
				 * level. */
    int bases[NUM_STACKS];	/* For each stack, index of first element on
				 * stack corresponding to this level (used to
				 * restore "numUsed" fields when popping out
				 * of a level. */
} StackLevel;

typedef struct ThreadSpecificData {
    int initialized;		/* 0 means the ThreadSpecific Data structure
				 * for the current thread needs to be
				 * initialized. */
    ElArray *stacks[NUM_STACKS];
    TkWindow *cachedWindow;	/* Lowest-level window currently loaded in
				 * stacks at present. NULL means stacks have
				 * never been used, or have been invalidated
				 * because of a change to the database. */
    /*
     * Information about all of the stack levels that are currently active.
     * This array grows dynamically to become as large as needed.
     */

    StackLevel *levels;		/* Array describing current stack. */
    int numLevels;		/* Total space allocated. */
    int curLevel;		/* Highest level currently in use. Note:
				 * curLevel is never 0! (I don't remember why
				 * anymore...) */
    int serial;			/* A serial number for all options entered
				 * into the database so far. It increments on
				 * each addition to the option database. It is
				 * used in computing option priorities, so
				 * that the most recent entry wins when
				 * choosing between options at the same
				 * priority level. */
    Element defaultMatch;	/* Special "no match" Element to use as
				 * default for searches.*/
} ThreadSpecificData;
static Tcl_ThreadDataKey dataKey;

/*
 * Forward declarations for functions defined in this file:
 */

static int		AddFromString(Tcl_Interp *interp, Tk_Window tkwin,
			    char *string, int priority);
static void		ClearOptionTree(ElArray *arrayPtr);
static ElArray *	ExtendArray(ElArray *arrayPtr, Element *elPtr);
static void		ExtendStacks(ElArray *arrayPtr, int leaf);
static int		GetDefaultOptions(Tcl_Interp *interp,
			    TkWindow *winPtr);
static ElArray *	NewArray(int numEls);
static void		OptionThreadExitProc(ClientData clientData);
static void		OptionInit(TkMainInfo *mainPtr);
static int		ParsePriority(Tcl_Interp *interp, char *string);
static int		ReadOptionFile(Tcl_Interp *interp, Tk_Window tkwin,
			    char *fileName, int priority);
static void		SetupStacks(TkWindow *winPtr, int leaf);

/*
 *--------------------------------------------------------------
 *
 * Tk_AddOption --
 *
 *	Add a new option to the option database.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Information is added to the option database.
 *
 *--------------------------------------------------------------
 */

void
Tk_AddOption(
    Tk_Window tkwin,		/* Window token; option will be associated
				 * with main window for this window. */
    CONST char *name,		/* Multi-element name of option. */
    CONST char *value,		/* String value for option. */
    int priority)		/* Overall priority level to use for this
				 * option, such as TK_USER_DEFAULT_PRIO or
				 * TK_INTERACTIVE_PRIO. Must be between 0 and
				 * TK_MAX_PRIO. */
{
    TkWindow *winPtr = ((TkWindow *) tkwin)->mainPtr->winPtr;
    register ElArray **arrayPtrPtr;
    register Element *elPtr;
    Element newEl;
    register CONST char *p;
    CONST char *field;
    int count, firstField;
    ptrdiff_t length;
#define TMP_SIZE 100
    char tmp[TMP_SIZE+1];
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));

    if (winPtr->mainPtr->optionRootPtr == NULL) {
	OptionInit(winPtr->mainPtr);
    }
    tsdPtr->cachedWindow = NULL;/* Invalidate the cache. */

    /*
     * Compute the priority for the new element, including both the overall
     * level and the serial number (to disambiguate with the level).
     */

    if (priority < 0) {
	priority = 0;
    } else if (priority > TK_MAX_PRIO) {
	priority = TK_MAX_PRIO;
    }
    newEl.priority = (priority << 24) + tsdPtr->serial;
    tsdPtr->serial++;

    /*
     * Parse the option one field at a time.
     */

    arrayPtrPtr = &(((TkWindow *) tkwin)->mainPtr->optionRootPtr);
    p = name;
    for (firstField = 1; ; firstField = 0) {
	/*
	 * Scan the next field from the name and convert it to a Tk_Uid. Must
	 * copy the field before calling Tk_Uid, so that a terminating NULL
	 * may be added without modifying the source string.
	 */

	if (*p == '*') {
	    newEl.flags = WILDCARD;
	    p++;
	} else {
	    newEl.flags = 0;
	}
	field = p;
	while ((*p != 0) && (*p != '.') && (*p != '*')) {
	    p++;
	}
	length = p - field;
	if (length > TMP_SIZE) {
	    length = TMP_SIZE;
	}
	strncpy(tmp, field, (size_t) length);
	tmp[length] = 0;
	newEl.nameUid = Tk_GetUid(tmp);
	if (isupper(UCHAR(*field))) {
	    newEl.flags |= CLASS;
	}

	if (*p != 0) {
	    /*
	     * New element will be a node. If this option can't possibly apply
	     * to this main window, then just skip it. Otherwise, add it to
	     * the parent, if it isn't already there, and descend into it.
	     */

	    newEl.flags |= NODE;
	    if (firstField && !(newEl.flags & WILDCARD)
		    && (newEl.nameUid != winPtr->nameUid)
		    && (newEl.nameUid != winPtr->classUid)) {
		return;
	    }
	    for (elPtr = (*arrayPtrPtr)->els, count = (*arrayPtrPtr)->numUsed;
		    ; elPtr++, count--) {
		if (count == 0) {
		    newEl.child.arrayPtr = NewArray(5);
		    *arrayPtrPtr = ExtendArray(*arrayPtrPtr, &newEl);
		    arrayPtrPtr = &((*arrayPtrPtr)
			    ->nextToUse[-1].child.arrayPtr);
		    break;
		}
		if ((elPtr->nameUid == newEl.nameUid)
			&& (elPtr->flags == newEl.flags)) {
		    arrayPtrPtr = &(elPtr->child.arrayPtr);
		    break;
		}
	    }
	    if (*p == '.') {
		p++;
	    }
	} else {
	    /*
	     * New element is a leaf. Add it to the parent, if it isn't
	     * already there. If it exists already, keep whichever value has
	     * highest priority.
	     */

	    newEl.child.valueUid = Tk_GetUid(value);
	    for (elPtr = (*arrayPtrPtr)->els, count = (*arrayPtrPtr)->numUsed;
		    ; elPtr++, count--) {
		if (count == 0) {
		    *arrayPtrPtr = ExtendArray(*arrayPtrPtr, &newEl);
		    return;
		}
		if ((elPtr->nameUid == newEl.nameUid)
			&& (elPtr->flags == newEl.flags)) {
		    if (elPtr->priority < newEl.priority) {
			elPtr->priority = newEl.priority;
			elPtr->child.valueUid = newEl.child.valueUid;
		    }
		    return;
		}
	    }
	}
    }
}

/*
 *--------------------------------------------------------------
 *
 * Tk_GetOption --
 *
 *	Retrieve an option from the option database.
 *
 * Results:
 *	The return value is the value specified in the option database for the
 *	given name and class on the given window. If there is nothing
 *	specified in the database for that option, then NULL is returned.
 *
 * Side effects:
 *	The internal caches used to speed up option mapping may be modified,
 *	if this tkwin is different from the last tkwin used for option
 *	retrieval.
 *
 *--------------------------------------------------------------
 */

Tk_Uid
Tk_GetOption(
    Tk_Window tkwin,		/* Token for window that option is associated
				 * with. */
    CONST char *name,		/* Name of option. */
    CONST char *className)	/* Class of option. NULL means there is no
				 * class for this option: just check for
				 * name. */
{
    Tk_Uid nameId, classId = NULL;
    char *masqName;
    register Element *elPtr, *bestPtr;
    register int count;
    StackLevel *levelPtr;
    int stackDepth[NUM_STACKS];
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));

    /*
     * Note: no need to call OptionInit here: it will be done by the
     * SetupStacks call below (squeeze out those nanoseconds).
     */

    if (tkwin != (Tk_Window) tsdPtr->cachedWindow) {
	SetupStacks((TkWindow *) tkwin, 1);
    }

    /*
     * Get a default "best" match.
     */

    bestPtr = &tsdPtr->defaultMatch;

    /*
     * For megawidget support, we want to have some widget options masquerade
     * as options for other widgets. For example, a combobox has a button in
     * it; this button ought to pick up the *Button.background, etc., options.
     * But because the class of the widget is Combobox, our normal search
     * won't get that option.
     *
     * To work around this, the option name field syntax was extended to allow
     * for a "." in the name; if this character occurs in the name, then it
     * indicates that this name contains a new window class and an option
     * name, ie, "Button.foreground". If we see this form in the name field,
     * we query the option database directly (since the option stacks will not
     * have the information we need).
     */

    masqName = strchr(name, (int)'.');
    if (masqName != NULL) {
	/*
	 * This option is masquerading with a different window class. Search
	 * the stack to the depth it was before the current window's
	 * information was pushed (the value for which is stored in the bases
	 * field).
	 */

	levelPtr = &tsdPtr->levels[tsdPtr->curLevel];
	nameId = Tk_GetUid(masqName+1);
	for (count = 0; count < NUM_STACKS; count++) {
	    stackDepth[count] = levelPtr->bases[count];
	}
    } else {
	/*
	 * No option masquerading here. Just use the current level to get the
	 * stack depths.
	 */

	nameId = Tk_GetUid(name);
	for (count = 0; count < NUM_STACKS; count++) {
	    stackDepth[count] = tsdPtr->stacks[count]->numUsed;
	}
    }

    /*
     * Probe the stacks for matches.
     */

    for (elPtr = tsdPtr->stacks[EXACT_LEAF_NAME]->els,
	     count = stackDepth[EXACT_LEAF_NAME]; count > 0;
	 elPtr++, count--) {
	if ((elPtr->nameUid == nameId)
		&& (elPtr->priority > bestPtr->priority)) {
	    bestPtr = elPtr;
	}
    }
    for (elPtr = tsdPtr->stacks[WILDCARD_LEAF_NAME]->els,
	     count = stackDepth[WILDCARD_LEAF_NAME]; count > 0;
	 elPtr++, count--) {
	if ((elPtr->nameUid == nameId)
		&& (elPtr->priority > bestPtr->priority)) {
	    bestPtr = elPtr;
	}
    }

    if (className != NULL) {
	classId = Tk_GetUid(className);
	for (elPtr = tsdPtr->stacks[EXACT_LEAF_CLASS]->els,
		 count = stackDepth[EXACT_LEAF_CLASS]; count > 0;
	     elPtr++, count--) {
	    if ((elPtr->nameUid == classId)
		    && (elPtr->priority > bestPtr->priority)) {
		bestPtr = elPtr;
	    }
	}
	for (elPtr = tsdPtr->stacks[WILDCARD_LEAF_CLASS]->els,
		 count = stackDepth[WILDCARD_LEAF_CLASS]; count > 0;
	     elPtr++, count--) {
	    if ((elPtr->nameUid == classId)
		    && (elPtr->priority > bestPtr->priority)) {
		bestPtr = elPtr;
	    }
	}
    }

    /*
     * If this option was masquerading with a different window class, probe
     * the option database now. Note that this will be inefficient if the
     * option database is densely populated, or if the widget has many
     * masquerading options.
     */

    if (masqName != NULL) {
	char *masqClass;
	Tk_Uid nodeId, winClassId, winNameId;
	unsigned int classNameLength;
	register Element *nodePtr, *leafPtr;
	static int searchOrder[] = {
	    EXACT_NODE_NAME, WILDCARD_NODE_NAME, EXACT_NODE_CLASS,
	    WILDCARD_NODE_CLASS, -1
	};
	int *currentPtr, currentStack, leafCount;

	/*
	 * Extract the masquerade class name from the name field.
	 */

	classNameLength	= (unsigned int)(masqName - name);
	masqClass = (char *) ckalloc(classNameLength + 1);
	strncpy(masqClass, name, classNameLength);
	masqClass[classNameLength] = '\0';

	winClassId = Tk_GetUid(masqClass);
	ckfree(masqClass);
	winNameId = ((TkWindow *)tkwin)->nameUid;

	levelPtr = &tsdPtr->levels[tsdPtr->curLevel];

	for (currentPtr = searchOrder; *currentPtr != -1; currentPtr++) {
	    currentStack = *currentPtr;
	    nodePtr = tsdPtr->stacks[currentStack]->els;
	    count = levelPtr->bases[currentStack];

	    /*
	     * For wildcard stacks, check all entries; for non-wildcard
	     * stacks, only check things that matched in the parent.
	     */

	    if (!(currentStack & WILDCARD)) {
		nodePtr += levelPtr[-1].bases[currentStack];
		count	-= levelPtr[-1].bases[currentStack];
	    }

	    if (currentStack & CLASS) {
		nodeId = winClassId;
	    } else {
		nodeId = winNameId;
	    }

	    for ( ; count > 0; nodePtr++, count--) {
		if (nodePtr->nameUid == nodeId) {
		    leafPtr = nodePtr->child.arrayPtr->els;
		    leafCount = nodePtr->child.arrayPtr->numUsed;
		    for ( ; leafCount > 0; leafPtr++, leafCount--) {
			if (leafPtr->flags & CLASS && className != NULL) {
			    if (leafPtr->nameUid == classId &&
				    leafPtr->priority > bestPtr->priority) {
				bestPtr = leafPtr;
			    }
			} else {
			    if (leafPtr->nameUid == nameId &&
				    leafPtr->priority > bestPtr->priority) {
				bestPtr = leafPtr;
			    }
			}
		    }
		}
	    }
	}
    }

    return bestPtr->child.valueUid;
}

/*
 *--------------------------------------------------------------
 *
 * Tk_OptionObjCmd --
 *
 *	This function is invoked to process the "option" Tcl command. See the
 *	user documentation for details on what it does.
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *--------------------------------------------------------------
 */

int
Tk_OptionObjCmd(
    ClientData clientData,	/* Main window associated with interpreter. */
    Tcl_Interp *interp,		/* Current interpreter. */
    int objc,			/* Number of Tcl_Obj arguments. */
    Tcl_Obj *CONST objv[])	/* Tcl_Obj arguments. */
{
    Tk_Window tkwin = (Tk_Window) clientData;
    int index, result;
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));

    static CONST char *optionCmds[] = {
	"add", "clear", "get", "readfile", NULL
    };

    enum optionVals {
	OPTION_ADD, OPTION_CLEAR, OPTION_GET, OPTION_READFILE
    };

    if (objc < 2) {
	Tcl_WrongNumArgs(interp, 1, objv, "cmd arg ?arg ...?");
	return TCL_ERROR;
    }

    result = Tcl_GetIndexFromObj(interp, objv[1], optionCmds, "option", 0,
	    &index);
    if (result != TCL_OK) {
	return result;
    }

    result = TCL_OK;
    switch ((enum optionVals) index) {
    case OPTION_ADD: {
	int priority;
	if ((objc != 4) && (objc != 5)) {
	    Tcl_WrongNumArgs(interp, 2, objv, "pattern value ?priority?");
	    return TCL_ERROR;
	}

	if (objc == 4) {
	    priority = TK_INTERACTIVE_PRIO;
	} else {
	    priority = ParsePriority(interp, Tcl_GetString(objv[4]));
	    if (priority < 0) {
		return TCL_ERROR;
	    }
	}
	Tk_AddOption(tkwin, Tcl_GetString(objv[2]), Tcl_GetString(objv[3]),
		priority);
	break;
    }

    case OPTION_CLEAR: {
	TkMainInfo *mainPtr;

	if (objc != 2) {
	    Tcl_WrongNumArgs(interp, 2, objv, "");
	    return TCL_ERROR;
	}
	mainPtr = ((TkWindow *) tkwin)->mainPtr;
	if (mainPtr->optionRootPtr != NULL) {
	    ClearOptionTree(mainPtr->optionRootPtr);
	    mainPtr->optionRootPtr = NULL;
	}
	tsdPtr->cachedWindow = NULL;
	break;
    }

    case OPTION_GET: {
	Tk_Window window;
	Tk_Uid value;

	if (objc != 5) {
	    Tcl_WrongNumArgs(interp, 2, objv, "window name class");
	    return TCL_ERROR;
	}
	window = Tk_NameToWindow(interp, Tcl_GetString(objv[2]), tkwin);
	if (window == NULL) {
	    return TCL_ERROR;
	}
	value = Tk_GetOption(window, Tcl_GetString(objv[3]),
		Tcl_GetString(objv[4]));
	if (value != NULL) {
	    Tcl_SetResult(interp, (char *)value, TCL_STATIC);
	}
	break;
    }

    case OPTION_READFILE: {
	int priority;

	if ((objc != 3) && (objc != 4)) {
	    Tcl_WrongNumArgs(interp, 2, objv, "fileName ?priority?");
	    return TCL_ERROR;
	}

	if (objc == 4) {
	    priority = ParsePriority(interp, Tcl_GetString(objv[3]));
	    if (priority < 0) {
		return TCL_ERROR;
	    }
	} else {
	    priority = TK_INTERACTIVE_PRIO;
	}
	result = ReadOptionFile(interp, tkwin, Tcl_GetString(objv[2]),
		priority);
	break;
    }
    }
    return result;
}

/*
 *--------------------------------------------------------------
 *
 * TkOptionDeadWindow --
 *
 *	This function is called whenever a window is deleted. It cleans up any
 *	option-related stuff associated with the window.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Option-related resources are freed. See code below for details.
 *
 *--------------------------------------------------------------
 */

void
TkOptionDeadWindow(
    register TkWindow *winPtr)	/* Window to be cleaned up. */
{
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));

    /*
     * If this window is in the option stacks, then clear the stacks.
     *
     * XXX: OptionThreadExitProc will be invoked before DeleteWindowsExitProc
     * XXX: if it is thread-specific (which it should be), invalidating the
     * XXX: tsd. Tk shutdown needs to be verified to handle this correctly.
     */

    if (tsdPtr->initialized && (winPtr->optionLevel != -1)) {
	int i;

	for (i = 1; i <= tsdPtr->curLevel; i++) {
	    tsdPtr->levels[i].winPtr->optionLevel = -1;
	}
	tsdPtr->curLevel = -1;
	tsdPtr->cachedWindow = NULL;
    }

    /*
     * If this window was a main window, then delete its option database.
     */

    if ((winPtr->mainPtr != NULL) && (winPtr->mainPtr->winPtr == winPtr)
	    && (winPtr->mainPtr->optionRootPtr != NULL)) {
	ClearOptionTree(winPtr->mainPtr->optionRootPtr);
	winPtr->mainPtr->optionRootPtr = NULL;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * TkOptionClassChanged --
 *
 *	This function is invoked when a window's class changes. If the window
 *	is on the option cache, this function flushes any information for the
 *	window, since the new class could change what is relevant.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The option cache may be flushed in part or in whole.
 *
 *----------------------------------------------------------------------
 */

void
TkOptionClassChanged(
    TkWindow *winPtr)		/* Window whose class changed. */
{
    int i, j, *basePtr;
    ElArray *arrayPtr;
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));

    if (winPtr->optionLevel == -1) {
	return;
    }

    /*
     * Find the lowest stack level that refers to this window, then flush all
     * of the levels above the matching one.
     */

    for (i = 1; i <= tsdPtr->curLevel; i++) {
	if (tsdPtr->levels[i].winPtr == winPtr) {
	    for (j = i; j <= tsdPtr->curLevel; j++) {
		tsdPtr->levels[j].winPtr->optionLevel = -1;
	    }
	    tsdPtr->curLevel = i-1;
	    basePtr = tsdPtr->levels[i].bases;
	    for (j = 0; j < NUM_STACKS; j++) {
		arrayPtr = tsdPtr->stacks[j];
		arrayPtr->numUsed = basePtr[j];
		arrayPtr->nextToUse = &arrayPtr->els[arrayPtr->numUsed];
	    }
	    if (tsdPtr->curLevel <= 0) {
		tsdPtr->cachedWindow = NULL;
	    } else {
		tsdPtr->cachedWindow = tsdPtr->levels[tsdPtr->curLevel].winPtr;
	    }
	    break;
	}
    }
}

/*
 *----------------------------------------------------------------------
 *
 * ParsePriority --
 *
 *	Parse a string priority value.
 *
 * Results:
 *	The return value is the integer priority level corresponding to
 *	string, or -1 if string doesn't point to a valid priority level. In
 *	this case, an error message is left in the interp's result.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
ParsePriority(
    Tcl_Interp *interp,		/* Interpreter to use for error reporting. */
    char *string)		/* Describes a priority level, either
				 * symbolically or numerically. */
{
    int priority, c;
    size_t length;

    c = string[0];
    length = strlen(string);
    if ((c == 'w')
	    && (strncmp(string, "widgetDefault", length) == 0)) {
	return TK_WIDGET_DEFAULT_PRIO;
    } else if ((c == 's')
	    && (strncmp(string, "startupFile", length) == 0)) {
	return TK_STARTUP_FILE_PRIO;
    } else if ((c == 'u')
	    && (strncmp(string, "userDefault", length) == 0)) {
	return TK_USER_DEFAULT_PRIO;
    } else if ((c == 'i')
	    && (strncmp(string, "interactive", length) == 0)) {
	return TK_INTERACTIVE_PRIO;
    } else {
	char *end;

	priority = strtoul(string, &end, 0);
	if ((end == string) || (*end != 0) || (priority < 0)
		|| (priority > 100)) {
	    Tcl_AppendResult(interp, "bad priority level \"", string,
		    "\": must be widgetDefault, startupFile, userDefault, ",
		    "interactive, or a number between 0 and 100", NULL);
	    return -1;
	}
    }
    return priority;
}

/*
 *----------------------------------------------------------------------
 *
 * AddFromString --
 *
 *	Given a string containing lines in the standard format for X resources
 *	(see other documentation for details on what this is), parse the
 *	resource specifications and enter them as options for tkwin's main
 *	window.
 *
 * Results:
 *	The return value is a standard Tcl return code. In the case of an
 *	error in parsing string, TCL_ERROR will be returned and an error
 *	message will be left in the interp's result. The memory at string is
 *	totally trashed by this function. If you care about its contents, make
 *	a copy before calling here.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
AddFromString(
    Tcl_Interp *interp,		/* Interpreter to use for reporting results. */
    Tk_Window tkwin,		/* Token for window: options are entered for
				 * this window's main window. */
    char *string,		/* String containing option specifiers. */
    int priority)		/* Priority level to use for options in this
				 * string, such as TK_USER_DEFAULT_PRIO or
				 * TK_INTERACTIVE_PRIO. Must be between 0 and
				 * TK_MAX_PRIO. */
{
    register char *src, *dst;
    char *name, *value;
    int lineNum;

    src = string;
    lineNum = 1;
    while (1) {

	/*
	 * Skip leading white space and empty lines and comment lines, and
	 * check for the end of the spec.
	 */

	while ((*src == ' ') || (*src == '\t')) {
	    src++;
	}
	if ((*src == '#') || (*src == '!')) {
	    do {
		src++;
		if ((src[0] == '\\') && (src[1] == '\n')) {
		    src += 2;
		    lineNum++;
		}
	    } while ((*src != '\n') && (*src != 0));
	}
	if (*src == '\n') {
	    src++;
	    lineNum++;
	    continue;
	}
	if (*src == '\0') {
	    break;
	}

	/*
	 * Parse off the option name, collapsing out backslash-newline
	 * sequences of course.
	 */

	dst = name = src;
	while (*src != ':') {
	    if ((*src == '\0') || (*src == '\n')) {
		char buf[32 + TCL_INTEGER_SPACE];

		sprintf(buf, "missing colon on line %d", lineNum);
		Tcl_SetResult(interp, buf, TCL_VOLATILE);
		return TCL_ERROR;
	    }
	    if ((src[0] == '\\') && (src[1] == '\n')) {
		src += 2;
		lineNum++;
	    } else {
		*dst = *src;
		dst++;
		src++;
	    }
	}

	/*
	 * Eliminate trailing white space on the name, and null-terminate
	 * it.
	 */

	while ((dst != name) && ((dst[-1] == ' ') || (dst[-1] == '\t'))) {
	    dst--;
	}
	*dst = '\0';

	/*
	 * Skip white space between the name and the value.
	 */

	src++;
	while ((*src == ' ') || (*src == '\t')) {
	    src++;
	}
	if (*src == '\0') {
	    char buf[32 + TCL_INTEGER_SPACE];

	    sprintf(buf, "missing value on line %d", lineNum);
	    Tcl_SetResult(interp, buf, TCL_VOLATILE);
	    return TCL_ERROR;
	}

	/*
	 * Parse off the value, squeezing out backslash-newline sequences
	 * along the way.
	 */

	dst = value = src;
	while (*src != '\n') {
	    if (*src == '\0') {
		char buf[32 + TCL_INTEGER_SPACE];

		sprintf(buf, "missing newline on line %d", lineNum);
		Tcl_SetResult(interp, buf, TCL_VOLATILE);
		return TCL_ERROR;
	    }
	    if (*src == '\\'){
		if (src[1] == '\n') {
		    src += 2;
		    lineNum++;
		    continue;
		} else if (src[1] == 'n') {
		    src += 2;
		    *dst++ = '\n';
		    continue;
		} else if (src[1] == '\t' || src[1] == ' ' || src[1] == '\\') {
		    ++src;
		} else if (src[1] >= '0' && src[1] <= '3' && src[2] >= '0' &&
			src[2] <= '9' && src[3] >= '0' && src[3] <= '9') {
		    *dst++ = ((src[1]&7)<<6) | ((src[2]&7)<<3) | (src[3]&7);
		    src += 4;
		    continue;
		}
	    }
	    *dst++ = *src++;
	}
	*dst = 0;

	/*
	 * Enter the option into the database.
	 */

	Tk_AddOption(tkwin, name, value, priority);
	src++;
	lineNum++;
    }
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * ReadOptionFile --
 *
 *	Read a file of options ("resources" in the old X terminology) and load
 *	them into the option database.
 *
 * Results:
 *	The return value is a standard Tcl return code. In the case of an
 *	error in parsing string, TCL_ERROR will be returned and an error
 *	message will be left in the interp's result.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static int
ReadOptionFile(
    Tcl_Interp *interp,		/* Interpreter to use for reporting results. */
    Tk_Window tkwin,		/* Token for window: options are entered for
				 * this window's main window. */
    char *fileName,		/* Name of file containing options. */
    int priority)		/* Priority level to use for options in this
				 * file, such as TK_USER_DEFAULT_PRIO or
				 * TK_INTERACTIVE_PRIO. Must be between 0 and
				 * TK_MAX_PRIO. */
{
    CONST char *realName;
    char *buffer;
    int result, bufferSize;
    Tcl_Channel chan;
    Tcl_DString newName, optString;

    /*
     * Prevent file system access in a safe interpreter.
     */

    if (Tcl_IsSafe(interp)) {
	Tcl_AppendResult(interp, "can't read options from a file in a",
		" safe interpreter", NULL);
	return TCL_ERROR;
    }

    realName = Tcl_TranslateFileName(interp, fileName, &newName);
    if (realName == NULL) {
	return TCL_ERROR;
    }
    chan = Tcl_OpenFileChannel(interp, realName, "r", 0);
    Tcl_DStringFree(&newName);
    if (chan == NULL) {
	Tcl_ResetResult(interp);
	Tcl_AppendResult(interp, "couldn't open \"", fileName,
		"\": ", Tcl_PosixError(interp), NULL);
	return TCL_ERROR;
    }

    /*
     * Compute size of file by seeking to the end of the file. This will
     * overallocate if we are performing CRLF translation.
     */

    bufferSize = (int) Tcl_Seek(chan, (Tcl_WideInt) 0, SEEK_END);
    (void) Tcl_Seek(chan, (Tcl_WideInt) 0, SEEK_SET);

    if (bufferSize < 0) {
	Tcl_AppendResult(interp, "error seeking to end of file \"",
		fileName, "\":", Tcl_PosixError(interp), NULL);
	Tcl_Close(NULL, chan);
	return TCL_ERROR;

    }
    buffer = (char *) ckalloc((unsigned) bufferSize+1);
    bufferSize = Tcl_Read(chan, buffer, bufferSize);
    if (bufferSize < 0) {
	Tcl_AppendResult(interp, "error reading file \"", fileName, "\":",
		Tcl_PosixError(interp), NULL);
	Tcl_Close(NULL, chan);
	return TCL_ERROR;
    }
    Tcl_Close(NULL, chan);
    buffer[bufferSize] = 0;
    if ((bufferSize>2) && !memcmp(buffer, "\357\273\277", 3)) {
	/* File starts with UTF-8 BOM */
	result = AddFromString(interp, tkwin, buffer+3, priority);
    } else {
	Tcl_DStringInit(&optString);
	Tcl_ExternalToUtfDString(NULL, buffer, bufferSize, &optString);
	result = AddFromString(interp, tkwin, Tcl_DStringValue(&optString),
		priority);
	Tcl_DStringFree(&optString);
    }
    ckfree(buffer);
    return result;
}

/*
 *--------------------------------------------------------------
 *
 * NewArray --
 *
 *	Create a new ElArray structure of a given size.
 *
 * Results:
 *	The return value is a pointer to a properly initialized element array
 *	with "numEls" space. The array is marked as having no active elements.
 *
 * Side effects:
 *	Memory is allocated.
 *
 *--------------------------------------------------------------
 */

static ElArray *
NewArray(
    int numEls)			/* How many elements of space to allocate. */
{
    register ElArray *arrayPtr;

    arrayPtr = (ElArray *) ckalloc(EL_ARRAY_SIZE(numEls));
    arrayPtr->arraySize = numEls;
    arrayPtr->numUsed = 0;
    arrayPtr->nextToUse = arrayPtr->els;
    return arrayPtr;
}

/*
 *--------------------------------------------------------------
 *
 * ExtendArray --
 *
 *	Add a new element to an array, extending the array if necessary.
 *
 * Results:
 *	The return value is a pointer to the new array, which will be
 *	different from arrayPtr if the array got expanded.
 *
 * Side effects:
 *	Memory may be allocated or freed.
 *
 *--------------------------------------------------------------
 */

static ElArray *
ExtendArray(
    register ElArray *arrayPtr,	/* Array to be extended. */
    register Element *elPtr)	/* Element to be copied into array. */
{
    /*
     * If the current array has filled up, make it bigger.
     */

    if (arrayPtr->numUsed >= arrayPtr->arraySize) {
	register ElArray *newPtr;

	newPtr = (ElArray *) ckalloc(EL_ARRAY_SIZE(2*arrayPtr->arraySize));
	newPtr->arraySize = 2*arrayPtr->arraySize;
	newPtr->numUsed = arrayPtr->numUsed;
	newPtr->nextToUse = &newPtr->els[newPtr->numUsed];
	memcpy(newPtr->els, arrayPtr->els,
		arrayPtr->arraySize * sizeof(Element));
	ckfree((char *) arrayPtr);
	arrayPtr = newPtr;
    }

    *arrayPtr->nextToUse = *elPtr;
    arrayPtr->nextToUse++;
    arrayPtr->numUsed++;
    return arrayPtr;
}

/*
 *--------------------------------------------------------------
 *
 * SetupStacks --
 *
 *	Arrange the stacks so that they cache all the option information for a
 *	particular window.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The stacks are modified to hold information for tkwin and all its
 *	ancestors in the window hierarchy.
 *
 *--------------------------------------------------------------
 */

static void
SetupStacks(
    TkWindow *winPtr,		/* Window for which information is to be
				 * cached. */
    int leaf)			/* Non-zero means this is the leaf window
				 * being probed. Zero means this is an
				 * ancestor of the desired leaf. */
{
    int level, i, *iPtr;
    register StackLevel *levelPtr;
    register ElArray *arrayPtr;
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));

    /*
     * The following array defines the order in which the current stacks are
     * searched to find matching entries to add to the stacks. Given the
     * current priority-based scheme, the order below is no longer relevant;
     * all that matters is that an element is on the list *somewhere*. The
     * ordering is a relic of the old days when priorities were determined
     * differently.
     */

    static int searchOrder[] = {WILDCARD_NODE_CLASS, WILDCARD_NODE_NAME,
	    EXACT_NODE_CLASS, EXACT_NODE_NAME, -1};

    if (winPtr->mainPtr->optionRootPtr == NULL) {
	OptionInit(winPtr->mainPtr);
    }

    /*
     * Step 1: make sure that options are cached for this window's parent.
     */

    if (winPtr->parentPtr != NULL) {
	level = winPtr->parentPtr->optionLevel;
	if ((level == -1) || (tsdPtr->cachedWindow == NULL)) {
	    SetupStacks(winPtr->parentPtr, 0);
	    level = winPtr->parentPtr->optionLevel;
	}
	level++;
    } else {
	level = 1;
    }

    /*
     * Step 2: pop extra unneeded information off the stacks and mark those
     * windows as no longer having cached information.
     */

    if (tsdPtr->curLevel >= level) {
	while (tsdPtr->curLevel >= level) {
	    tsdPtr->levels[tsdPtr->curLevel].winPtr->optionLevel = -1;
	    tsdPtr->curLevel--;
	}
	levelPtr = &tsdPtr->levels[level];
	for (i = 0; i < NUM_STACKS; i++) {
	    arrayPtr = tsdPtr->stacks[i];
	    arrayPtr->numUsed = levelPtr->bases[i];
	    arrayPtr->nextToUse = &arrayPtr->els[arrayPtr->numUsed];
	}
    }
    tsdPtr->curLevel = winPtr->optionLevel = level;

    /*
     * Step 3: if the root database information isn't loaded or isn't valid,
     * initialize level 0 of the stack from the database root (this only
     * happens if winPtr is a main window).
     */

    if ((tsdPtr->curLevel == 1)
	    && ((tsdPtr->cachedWindow == NULL)
	    || (tsdPtr->cachedWindow->mainPtr != winPtr->mainPtr))) {
	for (i = 0; i < NUM_STACKS; i++) {
	    arrayPtr = tsdPtr->stacks[i];
	    arrayPtr->numUsed = 0;
	    arrayPtr->nextToUse = arrayPtr->els;
	}
	ExtendStacks(winPtr->mainPtr->optionRootPtr, 0);
    }

    /*
     * Step 4: create a new stack level; grow the level array if we've run out
     * of levels. Clear the stacks for EXACT_LEAF_NAME and EXACT_LEAF_CLASS
     * (anything that was there is of no use any more).
     */

    if (tsdPtr->curLevel >= tsdPtr->numLevels) {
	StackLevel *newLevels;

	newLevels = (StackLevel *) ckalloc((unsigned)
		(tsdPtr->numLevels * 2 * sizeof(StackLevel)));
	memcpy(newLevels, tsdPtr->levels,
		tsdPtr->numLevels * sizeof(StackLevel));
	ckfree((char *) tsdPtr->levels);
	tsdPtr->numLevels *= 2;
	tsdPtr->levels = newLevels;
    }
    levelPtr = &tsdPtr->levels[tsdPtr->curLevel];
    levelPtr->winPtr = winPtr;
    arrayPtr = tsdPtr->stacks[EXACT_LEAF_NAME];
    arrayPtr->numUsed = 0;
    arrayPtr->nextToUse = arrayPtr->els;
    arrayPtr = tsdPtr->stacks[EXACT_LEAF_CLASS];
    arrayPtr->numUsed = 0;
    arrayPtr->nextToUse = arrayPtr->els;
    for (i = 0; i < NUM_STACKS; i++) {
	levelPtr->bases[i] = tsdPtr->stacks[i]->numUsed;
    }

    /*
     * Step 5: scan the current stack level looking for matches to this
     * window's name or class; where found, add new information to the stacks.
     */

    for (iPtr = searchOrder; *iPtr != -1; iPtr++) {
	register Element *elPtr;
	int count;
	Tk_Uid id;

	i = *iPtr;
	if (i & CLASS) {
	    id = winPtr->classUid;
	} else {
	    id = winPtr->nameUid;
	}
	elPtr = tsdPtr->stacks[i]->els;
	count = levelPtr->bases[i];

	/*
	 * For wildcard stacks, check all entries; for non-wildcard stacks,
	 * only check things that matched in the parent.
	 */

	if (!(i & WILDCARD)) {
	    elPtr += levelPtr[-1].bases[i];
	    count -= levelPtr[-1].bases[i];
	}
	for ( ; count > 0; elPtr++, count--) {
	    if (elPtr->nameUid != id) {
		continue;
	    }
	    ExtendStacks(elPtr->child.arrayPtr, leaf);
	}
    }
    tsdPtr->cachedWindow = winPtr;
}

/*
 *--------------------------------------------------------------
 *
 * ExtendStacks --
 *
 *	Given an element array, copy all the elements from the array onto the
 *	system stacks (except for irrelevant leaf elements).
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The option stacks are extended.
 *
 *--------------------------------------------------------------
 */

static void
ExtendStacks(
    ElArray *arrayPtr,		/* Array of elements to copy onto stacks. */
    int leaf)			/* If zero, then don't copy exact leaf
				 * elements. */
{
    register int count;
    register Element *elPtr;
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));

    for (elPtr = arrayPtr->els, count = arrayPtr->numUsed;
	    count > 0; elPtr++, count--) {
	if (!(elPtr->flags & (NODE|WILDCARD)) && !leaf) {
	    continue;
	}
	tsdPtr->stacks[elPtr->flags] =
		ExtendArray(tsdPtr->stacks[elPtr->flags], elPtr);
    }
}

/*
 *--------------------------------------------------------------
 *
 * OptionThreadExitProc --
 *
 *	Free data structures for option handling.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Option-related data structures get freed.
 *
 *--------------------------------------------------------------
 */

static void
OptionThreadExitProc(
    ClientData clientData)	/* not used */
{
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));

    if (tsdPtr->initialized) {
	int i;

	for (i = 0; i < NUM_STACKS; i++) {
	    ckfree((char *) tsdPtr->stacks[i]);
	}
	ckfree((char *) tsdPtr->levels);
	tsdPtr->initialized = 0;
    }
}

/*
 *--------------------------------------------------------------
 *
 * OptionInit --
 *
 *	Initialize data structures for option handling.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Option-related data structures get initialized.
 *
 *--------------------------------------------------------------
 */

static void
OptionInit(
    register TkMainInfo *mainPtr)
				/* Top-level information about window that
				 * isn't initialized yet. */
{
    int i;
    Tcl_Interp *interp;
    ThreadSpecificData *tsdPtr = (ThreadSpecificData *)
	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));
    Element *defaultMatchPtr = &tsdPtr->defaultMatch;

    /*
     * First, once-only initialization.
     */

    if (tsdPtr->initialized == 0) {
	tsdPtr->initialized = 1;
	tsdPtr->cachedWindow = NULL;
	tsdPtr->numLevels = 5;
	tsdPtr->curLevel = -1;
	tsdPtr->serial = 0;

	tsdPtr->levels = (StackLevel *)
		ckalloc((unsigned) (5*sizeof(StackLevel)));
	for (i = 0; i < NUM_STACKS; i++) {
	    tsdPtr->stacks[i] = NewArray(10);
	    tsdPtr->levels[0].bases[i] = 0;
	}

	defaultMatchPtr->nameUid = NULL;
	defaultMatchPtr->child.valueUid = NULL;
	defaultMatchPtr->priority = -1;
	defaultMatchPtr->flags = 0;
	Tcl_CreateThreadExitHandler(OptionThreadExitProc, NULL);
    }

    /*
     * Then, per-main-window initialization. Create and delete dummy
     * interpreter for message logging.
     */

    mainPtr->optionRootPtr = NewArray(20);
    interp = Tcl_CreateInterp();
    (void) GetDefaultOptions(interp, mainPtr->winPtr);
    Tcl_DeleteInterp(interp);
}

/*
 *--------------------------------------------------------------
 *
 * ClearOptionTree --
 *
 *	This function is called to erase everything in a hierarchical option
 *	database.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	All the options associated with arrayPtr are deleted, along with all
 *	option subtrees. The space pointed to by arrayPtr is freed.
 *
 *--------------------------------------------------------------
 */

static void
ClearOptionTree(
    ElArray *arrayPtr)		/* Array of options; delete everything
				 * referred to recursively by this. */
{
    register Element *elPtr;
    int count;

    for (count = arrayPtr->numUsed, elPtr = arrayPtr->els;  count > 0;
	    count--, elPtr++) {
	if (elPtr->flags & NODE) {
	    ClearOptionTree(elPtr->child.arrayPtr);
	}
    }
    ckfree((char *) arrayPtr);
}

/*
 *--------------------------------------------------------------
 *
 * GetDefaultOptions --
 *
 *	This function is invoked to load the default set of options for a
 *	window.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Options are added to those for winPtr's main window. If there exists a
 *	RESOURCE_MANAGER proprety for winPtr's display, that is used.
 *	Otherwise, the .Xdefaults file in the user's home directory is used.
 *
 *--------------------------------------------------------------
 */

static int
GetDefaultOptions(
    Tcl_Interp *interp,		/* Interpreter to use for error reporting. */
    TkWindow *winPtr)		/* Fetch option defaults for main window
				 * associated with this. */
{
    char *regProp, **regPropPtr = &regProp;
    int result, actualFormat;
    unsigned long numItems, bytesAfter;
    Atom actualType;

    /*
     * Try the RESOURCE_MANAGER property on the root window first.
     */

    regProp = NULL;
    result = XGetWindowProperty(winPtr->display,
	    RootWindow(winPtr->display, 0), XA_RESOURCE_MANAGER, 0, 100000,
	    False, XA_STRING, &actualType, &actualFormat, &numItems,
	    &bytesAfter, (unsigned char **) regPropPtr);

    if ((result == Success) && (actualType == XA_STRING)
	    && (actualFormat == 8)) {
	result = AddFromString(interp, (Tk_Window) winPtr, regProp,
		TK_USER_DEFAULT_PRIO);
	XFree(regProp);
	return result;
    }

    /*
     * No luck there. Try a .Xdefaults file in the user's home directory.
     */

    if (regProp != NULL) {
	XFree(regProp);
    }
    result = ReadOptionFile(interp, (Tk_Window) winPtr, "~/.Xdefaults",
	    TK_USER_DEFAULT_PRIO);
    return result;
}

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */