/* * tkUndo.c -- * * This module provides the implementation of an undo stack. * * Copyright (c) 2002 by Ludwig Callewaert. * * See the file "license.terms" for information on usage and redistribution * of this file, and for a DISCLAIMER OF ALL WARRANTIES. * * RCS: @(#) $Id: tkUndo.c,v 1.1.1.1 2007/07/10 15:05:17 duncan Exp $ */ #include "tkUndo.h" /* * TkUndoPushStack * Push elem on the stack identified by stack. * * Results: * None * * Side effects: * None. */ void TkUndoPushStack ( stack, elem ) TkUndoAtom ** stack; TkUndoAtom * elem; { elem->next = *stack; *stack = elem; } /* * TkUndoPopStack -- * Remove and return the top element from the stack identified by * stack. * * Results: * None * * Side effects: * None. */ TkUndoAtom * TkUndoPopStack ( stack ) TkUndoAtom ** stack ; { TkUndoAtom * elem = NULL; if (*stack != NULL ) { elem = *stack; *stack = elem->next; } return elem; } /* * TkUndoInsertSeparator -- * insert a separator on the stack, indicating a border for * an undo/redo chunk. * * Results: * None * * Side effects: * None. */ int TkUndoInsertSeparator ( stack ) TkUndoAtom ** stack; { TkUndoAtom * separator; if ( *stack != NULL && (*stack)->type != TK_UNDO_SEPARATOR ) { separator = (TkUndoAtom *) ckalloc(sizeof(TkUndoAtom)); separator->type = TK_UNDO_SEPARATOR; TkUndoPushStack(stack,separator); return 1; } else { return 0; } } /* * TkUndoClearStack -- * Clear an entire undo or redo stack and destroy all elements in it. * * Results: * None * * Side effects: * None. */ void TkUndoClearStack ( stack ) TkUndoAtom ** stack; /* An Undo or Redo stack */ { TkUndoAtom * elem; while ( (elem = TkUndoPopStack(stack)) ) { if ( elem->type != TK_UNDO_SEPARATOR ) { Tcl_DecrRefCount(elem->apply); Tcl_DecrRefCount(elem->revert); } ckfree((char *)elem); } *stack = NULL; } /* * TkUndoPushAction * Push a new elem on the stack identified by stack. * action and revert are given through Tcl_DStrings * * Results: * None * * Side effects: * None. */ void TkUndoPushAction ( stack, actionScript, revertScript ) TkUndoRedoStack * stack; /* An Undo or Redo stack */ Tcl_DString * actionScript; /* The script to get the action (redo) */ Tcl_DString * revertScript; /* The script to revert the action (undo) */ { TkUndoAtom * atom; atom = (TkUndoAtom *) ckalloc(sizeof(TkUndoAtom)); atom->type = TK_UNDO_ACTION; atom->apply = Tcl_NewStringObj(Tcl_DStringValue(actionScript),Tcl_DStringLength(actionScript)); Tcl_IncrRefCount(atom->apply); atom->revert = Tcl_NewStringObj(Tcl_DStringValue(revertScript),Tcl_DStringLength(revertScript)); Tcl_IncrRefCount(atom->revert); TkUndoPushStack(&(stack->undoStack), atom); TkUndoClearStack(&(stack->redoStack)); } /* * TkUndoInitStack * Initialize a new undo/redo stack * * Results: * un Undo/Redo stack pointer * * Side effects: * None. */ TkUndoRedoStack * TkUndoInitStack ( interp, maxdepth ) Tcl_Interp * interp; /* The interpreter */ int maxdepth; /* The maximum stack depth */ { TkUndoRedoStack * stack; /* An Undo/Redo stack */ stack = (TkUndoRedoStack *) ckalloc(sizeof(TkUndoRedoStack)); stack->undoStack = NULL; stack->redoStack = NULL; stack->interp = interp; stack->maxdepth = maxdepth; stack->depth = 0; return stack; } /* * TkUndoInitStack * Initialize a new undo/redo stack * * Results: * un Undo/Redo stack pointer * * Side effects: * None. */ void TkUndoSetDepth ( stack, maxdepth ) TkUndoRedoStack * stack; /* An Undo/Redo stack */ int maxdepth; /* The maximum stack depth */ { TkUndoAtom * elem; TkUndoAtom * prevelem; int sepNumber = 0; stack->maxdepth = maxdepth; if ((stack->maxdepth > 0) && (stack->depth > stack->maxdepth)) { /* * Maximum stack depth exceeded. We have to remove the last compound * elements on the stack. */ elem = stack->undoStack; prevelem = NULL; while (elem && (sepNumber <= stack->maxdepth)) { if (elem->type == TK_UNDO_SEPARATOR) { sepNumber++; } prevelem = elem; elem = elem->next; } prevelem->next = NULL; while ( elem ) { prevelem = elem; elem = elem->next; ckfree((char *) prevelem); } stack->depth = stack->maxdepth; } } /* * TkUndoClearStacks * Clear both the undo and redo stack * * Results: * None * * Side effects: * None. */ void TkUndoClearStacks ( stack ) TkUndoRedoStack * stack; /* An Undo/Redo stack */ { TkUndoClearStack(&(stack->undoStack)); TkUndoClearStack(&(stack->redoStack)); stack->depth = 0; } /* * TkUndoFreeStack * Clear both the undo and redo stack * also free the memory allocated to the u/r stack pointer * * Results: * None * * Side effects: * None. */ void TkUndoFreeStack ( stack ) TkUndoRedoStack * stack; /* An Undo/Redo stack */ { TkUndoClearStacks(stack); /* ckfree((TkUndoRedoStack *) stack); */ ckfree((char *) stack); } /* * TkUndoInsertUndoSeparator -- * insert a separator on the undo stack, indicating a border for * an undo/redo chunk. * * Results: * None * * Side effects: * None. */ void TkUndoInsertUndoSeparator ( stack ) TkUndoRedoStack * stack; { if ( TkUndoInsertSeparator(&(stack->undoStack)) ) { ++(stack->depth); TkUndoSetDepth(stack,stack->maxdepth); } } /* * TkUndoRevert -- * Undo a compound action on the stack. * * Results: * A TCL status code * * Side effects: * None. */ int TkUndoRevert ( stack ) TkUndoRedoStack * stack; { TkUndoAtom * elem; /* insert a separator on the undo and the redo stack */ TkUndoInsertUndoSeparator(stack); TkUndoInsertSeparator(&(stack->redoStack)); /* Pop and skip the first separator if there is one*/ elem = TkUndoPopStack(&(stack->undoStack)); if ( elem == NULL ) { return TCL_ERROR; } if ( ( elem != NULL ) && ( elem->type == TK_UNDO_SEPARATOR ) ) { ckfree((char *) elem); elem = TkUndoPopStack(&(stack->undoStack)); } while ( elem && (elem->type != TK_UNDO_SEPARATOR) ) { Tcl_EvalObjEx(stack->interp,elem->revert,TCL_EVAL_GLOBAL); TkUndoPushStack(&(stack->redoStack),elem); elem = TkUndoPopStack(&(stack->undoStack)); } /* insert a separator on the redo stack */ TkUndoInsertSeparator(&(stack->redoStack)); --(stack->depth); return TCL_OK; } /* * TkUndoApply -- * Redo a compound action on the stack. * * Results: * A TCL status code * * Side effects: * None. */ int TkUndoApply ( stack ) TkUndoRedoStack * stack; { TkUndoAtom *elem; /* insert a separator on the undo stack */ TkUndoInsertSeparator(&(stack->undoStack)); /* Pop and skip the first separator if there is one*/ elem = TkUndoPopStack(&(stack->redoStack)); if ( elem == NULL ) { return TCL_ERROR; } if ( ( elem != NULL ) && ( elem->type == TK_UNDO_SEPARATOR ) ) { ckfree((char *) elem); elem = TkUndoPopStack(&(stack->redoStack)); } while ( elem && (elem->type != TK_UNDO_SEPARATOR) ) { Tcl_EvalObjEx(stack->interp,elem->apply,TCL_EVAL_GLOBAL); TkUndoPushStack(&(stack->undoStack), elem); elem = TkUndoPopStack(&(stack->redoStack)); } /* insert a separator on the undo stack */ TkUndoInsertSeparator(&(stack->undoStack)); ++(stack->depth); return TCL_OK; }