/* * tkClipboard.c -- * * 	This file manages the clipboard for the Tk toolkit, * 	maintaining a collection of data buffers that will be * 	supplied on demand to requesting applications. * * Copyright (c) 1994 The Regents of the University of California. * Copyright (c) 1994-1995 Sun Microsystems, Inc. * * See the file "license.terms" for information on usage and redistribution * of this file, and for a DISCLAIMER OF ALL WARRANTIES. * * SCCS: @(#) tkClipboard.c 1.15 96/05/03 10:51:08 */#include "tkInt.h"#include "tkPort.h"#include "tkSelect.h"/* * Prototypes for procedures used only in this file: */static int		ClipboardAppHandler _ANSI_ARGS_((ClientData clientData,			    int offset, char *buffer, int maxBytes));static int		ClipboardHandler _ANSI_ARGS_((ClientData clientData,			    int offset, char *buffer, int maxBytes));static int		ClipboardWindowHandler _ANSI_ARGS_((			    ClientData clientData, int offset, char *buffer,			    int maxBytes));static void		ClipboardLostSel _ANSI_ARGS_((ClientData clientData));/* *---------------------------------------------------------------------- * * ClipboardHandler -- * *	This procedure acts as selection handler for the *	clipboard manager.  It extracts the required chunk of *	data from the buffer chain for a given selection target. * * Results: *	The return value is a count of the number of bytes *	actually stored at buffer. * * Side effects: *	None. * *---------------------------------------------------------------------- */static intClipboardHandler(clientData, offset, buffer, maxBytes)    ClientData clientData;	/* Information about data to fetch. */    int offset;			/* Return selection bytes starting at this				 * offset. */    char *buffer;		/* Place to store converted selection. */    int maxBytes;		/* Maximum # of bytes to store at buffer. */{    TkClipboardTarget *targetPtr = (TkClipboardTarget*) clientData;    TkClipboardBuffer *cbPtr;    char *srcPtr, *destPtr;    int count = 0;    int scanned = 0;    size_t length, freeCount;    /*     * Skip to buffer containing offset byte     */    for (cbPtr = targetPtr->firstBufferPtr; ; cbPtr = cbPtr->nextPtr) {	if (cbPtr == NULL) {	    return 0;	}	if (scanned + cbPtr->length > offset) {	    break;	}	scanned += cbPtr->length;    }    /*     * Copy up to maxBytes or end of list, switching buffers as needed.     */    freeCount = maxBytes;    srcPtr = cbPtr->buffer + (offset - scanned);    destPtr = buffer;    length = cbPtr->length - (offset - scanned);    while (1) {	if (length > freeCount) {	    strncpy(destPtr, srcPtr, freeCount);	    return maxBytes;	} else {	    strncpy(destPtr, srcPtr, length);	    destPtr += length;	    count += length;	    freeCount -= length;	}	cbPtr = cbPtr->nextPtr;	if (cbPtr == NULL) {	    break;	}	srcPtr = cbPtr->buffer;	length = cbPtr->length;    }    return count;}/* *---------------------------------------------------------------------- * * ClipboardAppHandler -- * *	This procedure acts as selection handler for retrievals of type *	TK_APPLICATION.  It returns the name of the application that *	owns the clipboard.  Note:  we can't use the default Tk *	selection handler for this selection type, because the clipboard *	window isn't a "real" window and doesn't have the necessary *	information. * * Results: *	The return value is a count of the number of bytes *	actually stored at buffer. * * Side effects: *	None. * *---------------------------------------------------------------------- */static intClipboardAppHandler(clientData, offset, buffer, maxBytes)    ClientData clientData;	/* Pointer to TkDisplay structure. */    int offset;			/* Return selection bytes starting at this				 * offset. */    char *buffer;		/* Place to store converted selection. */    int maxBytes;		/* Maximum # of bytes to store at buffer. */{    TkDisplay *dispPtr = (TkDisplay *) clientData;    size_t length;    char *p;    p = dispPtr->clipboardAppPtr->winPtr->nameUid;    length = strlen(p);    length -= offset;    if (length <= 0) {	return 0;    }    if (length > (size_t) maxBytes) {	length = maxBytes;    }    strncpy(buffer, p, length);    return length;}/* *---------------------------------------------------------------------- * * ClipboardWindowHandler -- * *	This procedure acts as selection handler for retrievals of *	type TK_WINDOW.  Since the clipboard doesn't correspond to *	any particular window, we just return ".".  We can't use Tk's *	default handler for this selection type, because the clipboard *	window isn't a valid window. * * Results: *	The return value is 1, the number of non-null bytes stored *	at buffer. * * Side effects: *	None. * *---------------------------------------------------------------------- */static intClipboardWindowHandler(clientData, offset, buffer, maxBytes)    ClientData clientData;	/* Not used. */    int offset;			/* Return selection bytes starting at this				 * offset. */    char *buffer;		/* Place to store converted selection. */    int maxBytes;		/* Maximum # of bytes to store at buffer. */{    buffer[0] = '.';    buffer[1] = 0;    return 1;}/* *---------------------------------------------------------------------- * * ClipboardLostSel -- * *	This procedure is invoked whenever clipboard ownership is *	claimed by another window.  It just sets a flag so that we *	know the clipboard was taken away. * * Results: *	None. * * Side effects: *	The clipboard is marked as inactive. * *---------------------------------------------------------------------- */static voidClipboardLostSel(clientData)    ClientData clientData;		/* Pointer to TkDisplay structure. */{    TkDisplay *dispPtr = (TkDisplay*) clientData;    dispPtr->clipboardActive = 0;}/* *---------------------------------------------------------------------- * * Tk_ClipboardClear -- * *	Take control of the clipboard and clear out the previous *	contents.  This procedure must be invoked before any *	calls to Tk_AppendToClipboard. * * Results: *	A standard Tcl result.  If an error occurs, an error message is *	left in interp->result. * * Side effects: *	From now on, requests for the CLIPBOARD selection will be *	directed to the clipboard manager routines associated with *	clipWindow for the display of tkwin.  In order to guarantee *	atomicity, no event handling should occur between *	Tk_ClipboardClear and the following Tk_AppendToClipboard *	calls.  This procedure may cause a user-defined LostSel command  * 	to be invoked when the CLIPBOARD is claimed, so any calling *	function should be reentrant at the point Tk_ClipboardClear is *	invoked. * *---------------------------------------------------------------------- */intTk_ClipboardClear(interp, tkwin)    Tcl_Interp *interp;		/* Interpreter to use for error reporting. */    Tk_Window tkwin;		/* Window in application that is clearing				 * clipboard;  identifies application and				 * display. */{    TkWindow *winPtr = (TkWindow *) tkwin;    TkDisplay *dispPtr = winPtr->dispPtr;    TkClipboardTarget *targetPtr, *nextTargetPtr;    TkClipboardBuffer *cbPtr, *nextCbPtr;    if (dispPtr->clipWindow == NULL) {	int result;	result = TkClipInit(interp, dispPtr);	if (result != TCL_OK) {	    return result;	}    }    /*     * Discard any existing clipboard data and delete the selection     * handler(s) associated with that data.     */    for (targetPtr = dispPtr->clipTargetPtr; targetPtr != NULL;	    targetPtr = nextTargetPtr) {	for (cbPtr = targetPtr->firstBufferPtr; cbPtr != NULL;		cbPtr = nextCbPtr) {	    ckfree(cbPtr->buffer);	    nextCbPtr = cbPtr->nextPtr;	    ckfree((char *) cbPtr);	}	nextTargetPtr = targetPtr->nextPtr;	Tk_DeleteSelHandler(dispPtr->clipWindow, dispPtr->clipboardAtom,		targetPtr->type);	ckfree((char *) targetPtr);    }    dispPtr->clipTargetPtr = NULL;    /*     * Reclaim the clipboard selection if we lost it.     */    if (!dispPtr->clipboardActive) {	Tk_OwnSelection(dispPtr->clipWindow, dispPtr->clipboardAtom,		ClipboardLostSel, (ClientData) dispPtr);	dispPtr->clipboardActive = 1;    }    dispPtr->clipboardAppPtr = winPtr->mainPtr;    return TCL_OK;}/* *---------------------------------------------------------------------- * * Tk_ClipboardAppend -- * * 	Append a buffer of data to the clipboard.  The first buffer of