Nebula 1995 August/NEBULA.mdf/SourceCode/AlexNeXTSTEPSource/Source/Chapter9_Text/Words/Document.m

Text File | 1993-04-08 | 4.0 KB | 195 lines

#import <appkit/appkit.h>
#import "Document.h"
#import "TextController.h"

#define SAVE NX_ALERTDEFAULT
#define CLOSE NX_ALERTALTERNATE
#define CANCEL NX_ALERTOTHER

#define SAVE_ERROR "Can't save file"
#define OPEN_ERROR "Can't open file"

@implementation Document

// initialize a new document
- init
{
    [super init];
    [NXApp loadNibSection:"Document.nib"
        owner:self withNames:NO];
    // make the document the delegate of the window
    // allows us to determine the current document
    // in showSavePanel:
    [window setDelegate:self];
    // make the document the delegate of the text
    // every time a key is pressed, the delegate
    // of the text object will receive a
    // textDidGetKeys: isEmpty: message
    // this allows us to update the window from
    // a clean state to a dirty state
    [theText setDelegate:self];
    return self;
}

// load a document from a file
- initDocumentFromFile:
    (const char *)fullPathName
{
    NXStream *stream;

    // obtain a stream for an existing file
    if (stream =
        NXMapFile(fullPathName, NX_READONLY))
        {
        [self init];
        // read text from stream
        [theText readText:stream];
        //update the window's title
        [window setTitle:fullPathName];
        // display the document
        [self showDocument];
        // free memory associated with stream
        NXCloseMemory(stream, NX_FREEBUFFER);
        return self;
        }
    else
        {
        [self showError:OPEN_ERROR];
        return nil;
        }
}

// display the document -- one improvement
// is to stagger the window rather than display
// each one on top of each other
- showDocument
{
    // set the text selection to 1st char
    [theText setSel:0 :0];
    [window makeKeyAndOrderFront:self];
    return self;
}

// write the document to file
- saveDocumentToFile:(const char *)fullPathName
{
    NXStream *stream = NULL;
    const char* title = [window title];

    // get a stream first
    if (stream =
        (NXOpenMemory(NULL, 0, NX_WRITEONLY)))
        {
        // write text into stream
        [theText writeText:stream];
        // write the stream to the file
        // and check for error code
        if (NXSaveToFile(stream, fullPathName) != 0)
            {
            [self showError:SAVE_ERROR];
            // free stream
            NXCloseMemory(stream, NX_FREEBUFFER);
            return nil;
            }
        else
            // save succeeded: update misc info
            {
            // update the title of the window
            [window setTitle:fullPathName];
            // update window to clean state
            [window setDocEdited:NO];
            // free stream
            NXCloseMemory(stream, NX_FREEBUFFER);
            }
        }
    else
        // Couldn't get stream
        {
        [self showError:SAVE_ERROR];
        return nil;
        }
    return self;
}

// use an Alert panel to display error messages
- showError:(const char *)errorMessage
{
    NXRunAlertPanel(NULL,
        errorMessage, "OK", NULL, NULL);
    return self;
}

// called every time a key is pressed
// if the window is marked dirty, we don't do
// anything -- if it's not dirty, we set
// it to dirty
- textDidGetKeys:sender isEmpty:(BOOL)flag
{
    // if window is not dirty, then set
    // it to dirty
    if ([window isDocEdited] == NO)
        [window setDocEdited:YES];
    return self;
}

- free
{
    // free the window since it's
    // dynamically allocated
    [window free];
    // free everything allocated
    // by the superclasses
    return [super free];
}

// since the document object is the delegate of
// the window, the window will, before closing,
// send a windowWillClose: message to
// the document
- windowWillClose:sender
{
    int result;

    // display alert panel only if window
    // is dirty
    if ([window isDocEdited])
        {
        result = NXRunAlertPanel
            ([NXApp appName],
            "Unsaved changes. Close Anyway?\n",
            "Save",
            "Close anyway",
            "Cancel");

        switch(result)
            {
            case SAVE:
                // display savepanel;
                // showSavePanel: returns
                // nil if user presses Cancel
                // this prevents window from
                // closing
                return [textController
                    showSavePanel:sender];
                break;
            case CLOSE:
                // delay freeing the object until
                // we are done with the current
                // event (closing the window)
                return [NXApp delayedFree:self];
            case CANCEL:
                // returning nil prevents the window
                // from closing
                return nil;
            }
        }
    return self;
}

- window
{
    return window;
}

@end