tkclipboard.c

linux系统下的音频通信

/*
 * 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 int
ClipboardHandler(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 int
ClipboardAppHandler(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 int
ClipboardWindowHandler(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 void
ClipboardLostSel(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.
 *
 *----------------------------------------------------------------------
 */

int
Tk_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