TweetFollow Us on Twitter

X Files Carbonara

Volume Number: 19 (2003)
Issue Number: 8
Column Tag: Recipes

X Files Carbonara

Making Navigation Easier for the Impatient

by Richard Patterson

The Good ol' ways

Before I was coerced into being carbonized, I had a simple scrap of code I could grab and use whenever I needed my application to create and write a file.

   long            byteCounter;
   StandardFileReply   reply;
   FSSpec         asciFile;
   short         asciFileNum;
   char            *textData;
   OSErr         err = noErr;
StandardPutFile("\pSave Text Data as:", 
"\pFullLookupTable.txt", &reply);
   if(reply.sfGood)
   {
      asciFile = reply.sfFile;
      FSpDelete(&asciFile);
// ignore any error caused if there is no such file
      err = FSpCreate(&asciFile,'XCEL','TEXT', -1);   /* -1 = system script */
      err = FSpOpenDF(&asciFile, fsCurPerm, &asciFileNum);
      if (err != noErr) return err;
      err = FSWrite(asciFileNum, &byteCounter, textData);
      if (err != noErr) return err;
      err = FSClose(asciFileNum);
   }
   return err;

It couldn't get much more straightforward than that. Those were the days when the Toolbox really made life simpler for a programmer. It helped me tell the user (generally myself) what he was supposed to do and even suggest a default name for the file. The only suspect part of this code was the shortcut method of insuring that the file was indeed a virgin file by attempting to delete it before (re)creating it. I knew there were more elegant ways to let StandardPutFile tell me that the user was replacing an existing file rather than just creating a brand new one, but most of the time I didn't care. I just wanted to write the file and get on with it. (Most of my programming is for in-house use only, so I can get away with quick-and-dirty solutions that you should only try at home.)

Recently I was desperately trying to debug an After Effects plug-in to send images to a film recorder, and I realized the only way I was going to be able tell what was going on would be to save a file capturing the state of the image at a certain point. I don't write applications that write files all that often, but years ago I acquired the prejudice that reading and writing files is one of the most basic functions the operating system needs to do and should therefore be a very simple programming task. So I resurrected a scrap of code designed to save an image buffer as a simple Photoshop file and threw it into the soup.

The next thing I knew I was spending two days trying to figure out how to replace the method shown above with something that would work inside my carbon code running on OS-X. I found myself floating around in all kinds of convoluted discussions of Apple Events and Unicode text. I eventually vented my frustration on Apple Developer Support whose suggestions for further reading and examples only seemed to complicate what I thought I was beginning to grasp. Fortunately the support technician was very patient, and I was able to crystallize my ferment into a rational suggestion that OS-X should provide a much simpler higher level function to help the less experienced programmer create and write a file. The support technician agreed that was a good idea, but indicated that it was not at the top of their priorites. When I finally saw the light thanks to Mr. K.J. Bricknell's indispensable tome, Carbon Programming; I realized that perhaps I should write a sample function that might spare someone else the agony I had just experienced.

Non Standard

The functions for opening and writing to a file (FspOpenDF and FSWrite) still work in Carbon on OS-X, but the StandardPutFile and StandardGetFile functions have been replaced by Navigation Services. The system had just outgrown the functionality provided by the Standard File Package. There is a Navigation Services function NavPutFile that was the original replacement for StandardPutFile, but with OS-X Apple recommends that we use NavCreatePutFileDialog. If I had been keeping up, the transition from StandardPutFile to NavPutFile to NavCreatePutFileDialog might have been smooth and effortless. Instead I woke up and found the following definition staring me in the face:

OSStatus NavCreatePutFileDialog (
   const NavDialogCreationOptions * inOptions,
   OSType inFileType,
   OSType inFileCreator,
   NavEventUPP inEventProc,
   void * inClientData,
   NavDialogRef * outDialog
);

Then I discovered there were 11 other functions I must call before I can have an FSSpec to use in the familiar way.

What I wanted was one function that took care of all the user interaction and just gave me a ready-to-wear FSSpec. It would need to know what kind of file I am trying to create, so there are three things I need to give it: the file type, the file creator and a pointer to the FSSpec.

OSErr SimpleNavPutFile(   OSType fileType, 
OSType fileCreator, 
FSSpec *theFileSpec)
{
   OSStatus         theStatus;
   NavDialogRef   theDialog;
   NavReplyRecord theReply;
   AEDesc            aeDesc;
   FSRef            fsRefParent, fsRefDelete;
   UniChar         *nameBuffer;
   UniCharCount   nameLength;
   FInfo            fileInfo;
   OSErr            err = noErr;
   theStatus = NavCreatePutFileDialog(NULL, fileType, fileCreator,
NULL, NULL,
&theDialog);
   NavDialogRun(theDialog);
   theStatus = NavDialogGetReply ( theDialog, &theReply); 
   NavDialogDispose(theDialog);
         
   if(!theReply.validRecord)
   {
      // Assuming the user changed his/her mind? No harm; no foul.
      // Still need to indicate that a file has not been created
      return -1;   
   }   
                        
   err = AECoerceDesc(&theReply.selection, typeFSRef, &aeDesc);
   if(err != noErr) return err;
   err = AEGetDescData(&aeDesc, &fsRefParent, sizeof(FSRef));
   if(err != noErr) return err;
   nameLength = 
(UniCharCount)CFStringGetLength(theReply.saveFileName);
   nameBuffer = (UniChar *) NewPtr((long)nameLength);
   CFStringGetCharacters(theReply.saveFileName, 
CFRangeMake(0, (long)nameLength), 
&nameBuffer[0]);
   if(nameBuffer == NULL) return -1; // generic error
   if(theReply.replacing)
   {
      err = FSMakeFSRefUnicode(&fsRefParent, 
nameLength, nameBuffer, 
                        kTextEncodingUnicodeDefault, 
                        &fsRefDelete);
      if(err == noErr) err = FSDeleteObject(&fsRefDelete);
      if(err == fBsyErr)
      {
         DisposePtr((Ptr)nameBuffer);
         return err;
      }
   }
   
   err = FSCreateFileUnicode(&fsRefParent, nameLength, nameBuffer,
                      kFSCatInfoNone, NULL, NULL,
theFileSpec);
   
   err = FSpGetFInfo(theFileSpec, &fileInfo);
   fileInfo.fdType = fileType;
   fileInfo.fdCreator = fileCreator;
   err = FSpSetFInfo(theFileSpec, &fileInfo);
   
   return err;
}   

So now my original scrap of code would become:

long                           byteCounter;
   StandardFileReply      reply;
   FSSpec                     asciFile;
   short                     asciFileNum;
   char                        *textData;
   OSErr                     err = noErr;
err = SimpleNavPutFile('TEXT', 'XCEL' &asciFile);
   if(err == noErr)   // a file was created
   {
      err = FSpOpenDF(&asciFile, fsCurPerm, &asciFileNum);
      if (err != noErr) return err;
      err = FSWrite(asciFileNum, &byteCounter, textData);
      if (err != noErr) return err;
      err = FSClose(asciFileNum);
   }
   return err;

I've sacrificed a little functionality in the dialog, since I can no longer suggest a default file name and prompt the forgetful user about what he is supposed to be doing. This scrap is fewer lines of code than my original, though, and even easier to use. I shall not attempt to explain what all the functions are doing in my SimpleNavPutFile. All I can say is that this works on my machine and is not meant to be anything other than a quick and dirty solution. Note that it includes the call creating the file and deals with the choice to replace an existing file. It may just amount to the same thing as using the now-deprecated NavPutFile, but I believe it lets OS-X put up the latest and greatest file navigation dialog.

I should confess that this solution will fail with OS-9 because it gives up if it cannot coerce the AEDesc to an FSRef. Bricknell's book has a discussion on page 960 of how to derive the FSSpec in OS-9 when this coercion fails. I have not included it, because my immediate concern was getting over the hump in OS-X, and I want to keep this as simple as possible.

The corresponding SimpleNavGetFile is built around

OSStatus NavCreateGetFileDialog (
   const NavDialogCreationOptions * inOptions,   
   NavTypeListHandle inTypeList,      // can be NULL
   NavEventUPP inEventProc,         // can be NULL
   NavPreviewUPP inPreviewProc,      // can be NULL
   NavObjectFilterUPP inFilterProc,   // can be NULL
   void * inClientData,            // can be NULL
   NavDialogRef * outDialog
);

Most of the parameters which can be set to NULL have system defaults that will be used when they are NULL. Setting the NavTypeListHandle to NULL simply results in no file filtering in the dialog. In order to avoid dealing with the NavDialogCreationOptions you can use NavGetDefaultDialogCreationOptions to set everything to a default.

SimpleNavGetFile(FSSpec *theFileSpec)
{   
   OSStatus                        theStatus;
NavDialogRef                     theDialog;
   NavReplyRecord                theReply;
NavDialogCreationOptions    inOptions;
AEKeyword                        theKeyword;
   DescType                      actualType;
   Size                          actualSize;
   OSErr                           err = noErr;
   
   NavGetDefaultDialogCreationOptions(&inOptions);
   theStatus = NavCreateGetFileDialog(&inOptions, 
NULL, NULL, NULL, NULL, NULL, 
&theDialog);
   NavDialogRun(theDialog);
   theStatus = NavDialogGetReply ( theDialog, &theReply); 
   NavDialogDispose(theDialog);
      
   if(!theReply.validRecord)
   {
      return -1;      
// Assuming the user changed his/her mind? 
// No harm; no foul, but need to know 
// not to try to open the file.
   }   
                        
       // Get a pointer to selected file
err = AEGetNthPtr(&(theReply.selection), 1,
                           typeFSS, &theKeyword,
                           &actualType, theFileSpec,
                           sizeof(FSSpec),
                           &actualSize);
      
   return err;
}   

If you want to filter files to limit the options provided the user in the Navigation Dialog, you can either use an 'open' resource created with a resource editor or you can create a NavTypeList. To use an 'open' resource you get the NavTypeListHandle with a GetResoure function.

NavTypeListHandle typeList = 
(NavTypeListHandle)GetResource('open', 128);
   theStatus = NavCreateGetFileDialog(&inOptions, 
typeList, 
NULL, NULL, NULL, NULL, 
&theDialog);

The 128 is just the number of the resource you have created. If no such resource is found typeList will be given a NULL value and you will be doing no file filtering.

To create your own NavTypeList from scratch you need only fill in a few blanks.

   NavTypeList            inTypeList;
   NavTypeListPtr      inTypeListPtr;
   
   inTypeList.componentSignature = kNavGenericSignature;
   inTypeList.osTypeCount = 1;
   inTypeList.osType[0] = 'TEXT';
   
inTypeListPtr = &inTypeList;
   theStatus = NavCreateGetFileDialog(&inOptions, 
&inTypeListPtr, 
NULL, NULL, NULL, NULL, 
&theDialog);

I have used a NavTypeListPtr just to minimize the confusion when it is necessary to pass a NavTypeListHandle to NavCreateGetFileDialog. The kNavGenericSignature is a system constant which tells it not to filter files by their creator. If you wanted to choose from only Excel files you could put 'XCEL' here instead. Since the osType is an array you can list several file types for a given appliction signature, and you can also make NavTypeList itself an array so that the handle tells the dialog to display any number of file types from any number of specifica applications. If you need to do this, though, you are on your own.


Richard Patterson is in charge of digital imaging at Illusion Arts, a visual effects facility in Van Nuys, CA, specializing in matte paintings and bluescreen compositing for movies. You can reach him at richard@illusion-arts.com.

 
AAPL
$524.94
Apple Inc.
+5.93
MSFT
$40.01
Microsoft Corpora
-0.39
GOOG
$536.10
Google Inc.
-20.44

MacTech Search:
Community Search:

Software Updates via MacUpdate

Mac DVDRipper Pro 4.1.7 - Copy, backup,...
Mac DVDRipper Pro is the DVD backup solution that lets you protect your DVDs from scratches, save your batteries by reading your movies from your hard disk, manage your collection with just a few... Read more
PDFpenPro 6.2 - Advanced PDF toolkit for...
PDFpenPro allows users to edit PDF's easily. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even correct text and edit graphics! Create... Read more
PDFpen 6.2 - Edit and annotate PDFs with...
PDFpen allows users to easily edit PDF's. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even correct text and edit graphics! Features... Read more
Monolingual 1.5.9 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. It requires a 64-bit capable Intel-based Mac and at least... Read more
Maya 2015 - Professional 3D modeling and...
Maya is an award-winning software and powerful, integrated 3D modeling, animation, visual effects, and rendering solution. Because Maya is based on an open architecture, all your work can be scripted... Read more
Starcraft II: Wings of Liberty 1.1.1.180...
Download the patch by launching the Starcraft II game and downloading it through the Battle.net connection within the app. Starcraft II: Wings of Liberty is a strategy game played in real-time. You... Read more
Sibelius 7.5.0 - Music notation solution...
Sibelius is the world's best-selling music notation software for Mac. It is as intuitive to use as a pen, yet so powerful that it does most things in less than the blink of an eye. The demo includes... Read more
Typinator 5.9 - Speedy and reliable text...
Typinator turbo-charges your typing productivity. Type a little. Typinator does the rest. We've all faced projects that require repetitive typing tasks. With Typinator, you can store commonly used... Read more
MYStuff Pro 2.0.16 - Create inventories...
MYStuff Pro is the most flexible way to create detail-rich inventories for your home or small business. Add items to MYStuff by dragging and dropping existing information, uploading new images, or... Read more
TurboTax 2013.r17.002 - Manage your 2013...
TurboTax guides you through your tax return step by step, does all the calculations, and checks your return for errors and overlooked deductions. It lets you file your return electronically to get... Read more

Latest Forum Discussions

See All

Zynga Launches Brand New Farmville Exper...
Zynga Launches Brand New Farmville Experience with Farmville 2: Country Escape Posted by Tre Lawrence on April 18th, 2014 [ permalink ] | Read more »
David. Review
David. Review By Cata Modorcea on April 18th, 2014 Our Rating: :: MINIMALISTIC IN A DIFFERENT WAYUniversal App - Designed for iPhone and iPad David is a minimalistic game wrapped inside of a soothing atmosphere in which the hero... | Read more »
Eyefi Unveils New Eyefi Cloud Service Th...
Eyefi Unveils New Eyefi Cloud Service That Allows Users to Share Media Across Personal Devices Posted by Tre Lawrence on April 18th, 2014 [ permalink ] | Read more »
Tales from the Dragon Mountain: The Lair...
Tales from the Dragon Mountain: The Lair Review By Jennifer Allen on April 18th, 2014 Our Rating: :: STEADY ADVENTURINGiPad Only App - Designed for the iPad Treading a safe path, Tales from the Dragon Mountain: The Lair is a... | Read more »
Yahoo Updates Flickr App with Advanced E...
Yahoo Updates Flickr App with Advanced Editing Features and More Posted by Tre Lawrence on April 18th, 2014 [ permalink ] | Read more »
My Incredible Body - A Kid's App to...
My Incredible Body - A Kid's App to Learn about the Human Body 1.1.00 Device: iOS Universal Category: Education Price: $2.99, Version: 1.1.00 (iTunes) Description: Wouldn’t it be cool to look inside yourself and see what was going on... | Read more »
Trials Frontier Review
Trials Frontier Review By Carter Dotson on April 18th, 2014 Our Rating: :: A ROUGH LANDINGUniversal App - Designed for iPhone and iPad Trials Frontier finally brings the famed stunt racing franchise to mobile, but how much does its... | Read more »
Evernote Business Notebook by Moleskin I...
Evernote Business Notebook by Moleskin Introduced – Support Available in Evernote for iOS Posted by Tre Lawrence on April 18th, 2014 [ permalink ] | Read more »
Sparkle Unleashed Review
Sparkle Unleashed Review By Jennifer Allen on April 18th, 2014 Our Rating: :: CLASSY MARBLE FLINGINGUniversal App - Designed for iPhone and iPad It’s a concept we’ve seen before, but Sparkle Unleashed is a solidly enjoyable orb... | Read more »
Tilt to Live 2: Redonkulus Receives its...
Tilt to Live 2: Redonkulus Receives its First Update – Gets New Brimstone Pinball DLC Posted by Rob Rich on April 18th, 2014 [ permalink ] | Read more »

Price Scanner via MacPrices.net

iMacs on sale for up to $160 off MSRP this we...
Best Buy has iMacs on sale for up to $160 off MSRP for a limited time. Choose free home shipping or free instant local store pickup (if available). Prices are valid for online orders only, in-store... Read more
iPad Airs on sale this weekend for up to $100...
Best Buy has WiFi iPad Airs on sale for $50 off MSRP and WiFi + Cellular iPad Airs on sale for $100 off MSRP on their online store for a limited time, with prices now starting at $449. Choose free... Read more
Apple restocks refurbished Mac minis starting...
The Apple Store has restocked Apple Certified Refurbished Mac minis for up to $150 off the cost of new models. Apple’s one-year warranty is included with each mini, and shipping is free: - 2.5GHz Mac... Read more
Hyundai Brings Apple CarPlay To The 2015 Sona...
Hyundai Motor America has announced it will bring Apple CarPlay functionality to the 2015 Sonata. CarPlay is pitched as a smarter, safer and easier way to use iPhone in the car and gives iPhone users... Read more
Updated iPads Coming Sooner Than We Had Thoug...
MacRumors, cites KGI securities analyst Ming Chi Kuo, well-respected as an Apple product prognisticator, saying that Apple will introduce an upgraded iPad Air and iPad mini in 2014/Q3, meaning the... Read more
Toshiba Unveils New High And Low End Laptop M...
Toshiba has announced new laptop models covering both the high-end and low-end of the notebook computer spectrum. Toshiba 4K Ultra HD Laptop Toshiba’s new Satellite P55t features one of the world’s... Read more
Save up to $270 with Apple refurbished 13-inc...
The Apple Store has Apple Certified Refurbished October 2013 13″ Retina MacBook Pros available starting at $1099, with models up to $270 off MSRP. Apple’s one-year warranty is standard, and shipping... Read more
Apple now offering refurbished iPad mini with...
The Apple Store has Certified Refurbished 2nd generation iPad minis with Retina Displays now available starting at $339. Apple’s one-year warranty is included with each model, and shipping is free.... Read more
Microsoft Blinks – Drops Microsoft Office 365...
Microsoft has dropped the annual subscription fee for Microsoft Office 365 Personal – which is needed in order to create and edit documents in Microsoft Office for iPad. However, Apple’s iOS and OS X... Read more
New AVG Vault Apps for iOS and Android Help K...
AVG Technologies N.V. an online security company for 177 million active users, has announced the launch of its latest mobile application, AVG Vault. The free app introduces an innovative user... Read more

Jobs Board

*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
*Apple* Retail - Manager - Holyoke - Apple I...
Job Summary Keeping an Apple Store thriving requires a diverse set of leadership skills, and as a Manager, you’re a master of them all. In the store’s fast-paced, Read more
*Apple* Retail - Manager - Apple (United Sta...
Job SummaryKeeping an Apple Store thriving requires a diverse set of leadership skills, and as a Manager, you're a master of them all. In the store's fast-paced, dynamic Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
*Apple* Retail - Market Leader - Cincinnati...
…challenges of developing individuals, building teams, and affecting growth across Apple Stores. You demonstrate successful leadership ability - focusing on excellence Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.