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.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

ScreenFlow 8.2.5 - Create screen recordi...
ScreenFlow is powerful, easy-to-use screencasting software for the Mac. With ScreenFlow you can record the contents of your entire monitor while also capturing your video camera, microphone and your... Read more
MegaSeg 6.1.1 - Professional DJ and radi...
MegaSeg is a complete solution for pro audio/video DJ mixing, radio automation, and music scheduling with rock-solid performance and an easy-to-use design. Mix with visual waveforms and Magic... Read more
Beamer 3.4 - Stream any movie file from...
Beamer streams to your Apple TV or Chromecast. Plays any movie file - Just like the popular desktop movie players, Beamer accepts all common formats, codecs and resolutions. AVI, MKV, MOV, MP4, WMV... Read more
FotoMagico 5.6.12 - Powerful slideshow c...
FotoMagico lets you create professional slideshows from your photos and music with just a few, simple mouse clicks. It sports a very clean and intuitive yet powerful user interface. High image... Read more
OmniGraffle Pro 7.12.1 - Create diagrams...
OmniGraffle Pro helps you draw beautiful diagrams, family trees, flow charts, org charts, layouts, and (mathematically speaking) any other directed or non-directed graphs. We've had people use... Read more
beaTunes 5.2.1 - Organize your music col...
beaTunes is a full-featured music player and organizational tool for music collections. How well organized is your music library? Are your artists always spelled the same way? Any R.E.M. vs REM?... Read more
HandBrake 1.3.0 - Versatile video encode...
HandBrake is a tool for converting video from nearly any format to a selection of modern, widely supported codecs. Features Supported Sources VIDEO_TS folder, DVD image or real DVD (unencrypted... Read more
Macs Fan Control 1.5.1.6 - Monitor and c...
Macs Fan Control allows you to monitor and control almost any aspect of your computer's fans, with support for controlling fan speed, temperature sensors pane, menu-bar icon, and autostart with... Read more
TunnelBear 3.9.3 - Subscription-based pr...
TunnelBear is a subscription-based virtual private network (VPN) service and companion app, enabling you to browse the internet privately and securely. Features Browse privately - Secure your data... Read more
calibre 4.3.0 - Complete e-book library...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more

Latest Forum Discussions

See All

The House of Da Vinci 2 gets a new gamep...
The House of Da Vinci launched all the way back in 2017. Now, developer Blue Brain Games is gearing up to deliver a second dose of The Room-inspired puzzling. Some fresh details have now emerged, alongside the game's first official trailer. [Read... | Read more »
Shoot 'em up action awaits in Battl...
BattleBrew Productions has just introduced another entry into its award winning, barrelpunk inspired, BattleSky Brigade series. Whilst its previous title BattleSky Brigade TapTap provided fans with idle town building gameplay, this time the... | Read more »
Arcade classic R-Type Dimensions EX blas...
If you're a long time fan of shmups and have been looking for something to play lately, Tozai Games may have just released an ideal game for you on iOS. R-Type Dimensions EX brings the first R-Type and its sequel to iOS devices. [Read more] | Read more »
Intense VR first-person shooter Colonicl...
Our latest VR obsession is Colonicle, an intense VR FPS, recently released on Oculus and Google Play, courtesy of From Fake Eyes and Goboogie Games. It's a pulse-pounding multiplayer shooter which should appeal to genre fanatics and newcomers alike... | Read more »
PUBG Mobile's incoming update bring...
PUGB Mobile's newest Royale Pass season they're calling Fury of the Wasteland arrives tomorrow and with it comes a fair chunk of new content to the game. We'll be seeing a new map, weapon and even a companion system. [Read more] | Read more »
PSA: Download Bastion for free, but wait...
There hasn’t been much news from Supergiant Games on mobile lately regarding new games, but there’s something going on with their first game. Bastion released on the App Store in 2012, and back then it was published by Warner Bros. This Warner... | Read more »
Apple Arcade: Ranked - 51+ [Updated 11.5...
This is Part 2 of our Apple Arcade Ranking list. To see part 1, go here. 51. Patterned [Read more] | Read more »
NABOKI is a blissful puzzler from acclai...
Acclaimed developer Rainbow Train's latest game, NABOKI, is set to launch for iOS, Android, and Steam on November 13th. It's a blissful puzzler all about taking levels apart in interesting, inventive ways. [Read more] | Read more »
A Case of Distrust is a narrative-driven...
A Case of Distrust a narrative-focused mystery game that's set in the roaring 20s. In it, you play as a detective with one of the most private eye sounding names ever – Phyllis Cadence Malone. You'll follow her journey in San Francisco as she... | Read more »
Brown Dust’s October update offers playe...
October is turning out to be a productive month for the Neowiz team, and a fantastic month to be a Brown Dust player. First, there was a crossover event with the popular manga That Time I Got Reincarnated as a Slime. Then, there was the addition of... | Read more »

Price Scanner via MacPrices.net

Score a 37% discount on Apple Smart Keyboards...
Amazon has Apple Smart Keyboards for current-generation 10″ iPad Airs and previous-generation 10″ iPad Pros on sale today for $99.99 shipped. That’s a 37% discount over Apple’s regular MSRP of $159... Read more
Apple has refurbished 2019 13″ 1.4GHz MacBook...
Apple has a full line of Certified Refurbished 2019 13″ 1.4GHz 4-Core Touch Bar MacBook Pros available starting at $1099 and up to $230 off MSRP. Apple’s one-year warranty is included, shipping is... Read more
2019 13″ 1.4GHz 4-Core MacBook Pros on sale f...
Amazon has new 2019 13″ 1.4GHz 4-Core Touch Bar MacBook Pros on sale for $150-$200 off Apple’s MSRP. These are the same MacBook Pros sold by Apple in its retail and online stores: – 2019 13″ 1.4GHz/... Read more
11″ 64GB Gray WiFi iPad Pro on sale for $674,...
Amazon has the 11″ 64GB Gray WiFi iPad Pro on sale today for $674 shipped. Their price is $125 off MSRP for this iPad, and it’s the lowest price available for the 64GB model from any Apple reseller. Read more
2019 15″ MacBook Pros available for up to $42...
Apple has a full line of 2019 15″ 6-Core and 8-Core Touch Bar MacBook Pros, Certified Refurbished, available for up to $420 off the cost of new models. Each model features a new outer case, shipping... Read more
2019 15″ MacBook Pros on sale this week for $...
Apple resellers B&H Photo and Amazon are offering the new 2019 15″ MacBook Pros for up to $300 off Apple’s MSRP including free shipping. These are the same MacBook Pros sold by Apple in its... Read more
Sunday Sale: AirPods with Wireless Charging C...
B&H Photo has Apple AirPods with Wireless Charging Case on sale for $159.99 through 11:59pm ET on November 11th. Their price is $40 off Apple’s MSRP, and it’s the lowest price available for these... Read more
Details of Sams Club November 9th one day App...
Through midnight Saturday night (November 9th), Sams Club online has several Apple products on sale as part of their One Day sales event. Choose free shipping or free local store pickup (if available... Read more
Sprint is offering the 64GB Apple iPhone 11 f...
Sprint has the new 64GB iPhone 11 available for $15 per month for new lines. That’s about 50% off their standard monthly lease of $29.17. Over is valid until November 24, 2019. The fine print: “Lease... Read more
New Sprint November iPhone deal: Lease one iP...
Switch to Sprint and purchase an Apple iPhone 11, 11 Pro, or 11 Pro Max, and get a second 64GB iPhone 11 for free. Requires 2 new lines or 1 upgrade-eligible line and 1 new line. Offer is valid from... Read more

Jobs Board

*Apple* Mobility Pro - Best Buy (United Stat...
**746087BR** **Job Title:** Apple Mobility Pro **Job Category:** Store Associates **Store NUmber or Department:** 000319-Harlem & Irving-Store **Job Description:** Read more
Best Buy *Apple* Computing Master - Best Bu...
**743392BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Store Associates **Store NUmber or Department:** 001171-Southglenn-Store **Job Read more
Best Buy *Apple* Computing Master - Best Bu...
**746015BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Store NUmber or Department:** 000372-Federal Way-Store **Job Description:** Read more
*Apple* Mobility Pro - Best Buy (United Stat...
**744658BR** **Job Title:** Apple Mobility Pro **Job Category:** Store Associates **Store NUmber or Department:** 000586-South Hills-Store **Job Description:** At Read more
Best Buy *Apple* Computing Master - Best Bu...
**741552BR** **Job Title:** Best Buy Apple Computing Master **Job Category:** Sales **Store NUmber or Department:** 000277-Metcalf-Store **Job Description:** **What Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.