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Text File  |  2000-06-23  |  4.6 KB  |  201 lines
  1. //    TPrefs.cp - Preference Object  
  2. // 
  3. // Apple Macintosh Developer Technical Support
  4. // Written by:  Vinnie Moscaritolo
  5. //
  6. //  Copyright (work in progress)  Apple Computer, Inc All rights reserved.
  7. //
  8. // You may incorporate this sample code into your applications without
  9. // restriction, though the sample code has been provided "AS IS" and the
  10. // responsibility for its operation is 100% yours.  However, what you are
  11. // not permitted to do is to redistribute the source as "DSC Sample Code"
  12. // after having made changes. If you're going to re-distribute the source,
  13. // we require that you make it clear in the source that the code was
  14. // descended from Apple Sample Code, but that you've made changes.
  15. // 
  16.  
  17. #include <PLStringFuncs.h>
  18. #include <string.h>
  19. #include <Files.h>
  20.  
  21. #include "TPrefs.h"
  22. #include "TMacException.h"
  23.  
  24.  
  25. // ---------------------------------------------------------------------------
  26.     TPrefs::TPrefs() //   
  27. // ---------------------------------------------------------------------------
  28. //  
  29. {
  30.  
  31.     fCollection = NewCollection();
  32.     ThrowMacErrIfNil(fCollection, nilHandleErr);    
  33.     
  34.  }
  35.  
  36.  
  37. // ---------------------------------------------------------------------------
  38.     TPrefs::~TPrefs() //   
  39. // ---------------------------------------------------------------------------
  40. //  
  41. { 
  42.     DisposeCollection (fCollection);
  43.  
  44. }
  45.  
  46. // ---------------------------------------------------------------------------
  47. OSErr TPrefs::Set(     FourCharCode    tag, 
  48.                      SInt32             id,
  49.                     SInt32             itemSize,
  50.                     void *            itemData)
  51. // ---------------------------------------------------------------------------
  52. //  
  53. { 
  54.     return AddCollectionItem(fCollection, tag, id, itemSize, itemData);
  55.  
  56. }
  57.  
  58. // ---------------------------------------------------------------------------
  59. OSErr TPrefs::Get(     FourCharCode    tag, 
  60.                      SInt32             id,
  61.                     SInt32*         itemSize,
  62.                     void *            itemData)
  63. // ---------------------------------------------------------------------------
  64. //  
  65. { 
  66.     return GetCollectionItem(fCollection, tag, id, itemSize, itemData);
  67. }
  68.  
  69.  
  70.  
  71. // ---------------------------------------------------------------------------
  72. OSErr TPrefs::Read() //   
  73. // ---------------------------------------------------------------------------
  74. //  
  75. { 
  76.     FSSpec    fss;
  77.     OSErr    err;
  78.     
  79.      err = this->GetPrefSpec(&fss);
  80.      if(!err)
  81.      {
  82.         short     fileRefNum;
  83.         Size    eof;
  84.         
  85.         SInt32     ByteCount;
  86.         SInt32     size;
  87.     
  88.          FSpOpenDF (&fss,fsRdPerm,&fileRefNum);
  89.  
  90.         GetEOF (fileRefNum, &eof);
  91.     
  92.         size = sizeof (SInt32);
  93.         err = FSRead (fileRefNum ,&size, &ByteCount);
  94.         if(!err)
  95.         {
  96.             if(ByteCount + sizeof (SInt32) <= eof)  
  97.             {
  98.                 Handle buffer = NewHandle (ByteCount);
  99.                 if (!buffer) err = MemError ( );
  100.                  HLockHi (buffer);
  101.  
  102.                 size = ByteCount;
  103.                 err = FSRead (fileRefNum ,&size, *buffer);
  104.                 if(!err)
  105.                 {
  106.                     err = UnflattenCollectionFromHdl ( fCollection, buffer);
  107.                 }
  108.                 HUnlock (buffer);
  109.             }
  110.             else 
  111.                 err = eofErr;
  112.         }
  113.         
  114.         FSClose (fileRefNum);
  115.      }
  116.      return err;
  117. }
  118.  
  119.  
  120.  
  121. // ---------------------------------------------------------------------------
  122. OSErr TPrefs::CreatePrefFile(FSSpec *fss)   
  123. // ---------------------------------------------------------------------------
  124. //  
  125. { 
  126.     return ( FSpCreate (fss, '????' ,kPrefsFileType,smSystemScript) );
  127.  
  128. }
  129.  
  130.  
  131. // ---------------------------------------------------------------------------
  132. OSErr TPrefs::GetPrefSpec(FSSpec *fss)   
  133. // ---------------------------------------------------------------------------
  134. //  
  135. { 
  136.     FSSpec         prefsFSS;
  137.  
  138. // find the pref folder
  139.     ThrowIfMacErr( FindFolder(kOnSystemDisk, kPreferencesFolderType, kCreateFolder, &prefsFSS.vRefNum, &prefsFSS.parID ));
  140.  
  141.     // make a file spec for the prefs file 
  142.     FSMakeFSSpec(prefsFSS.vRefNum, prefsFSS.parID , "\ppref file", fss);
  143.  
  144. // needs to be written to general case.
  145.     return (-1);
  146.  
  147. }
  148.  
  149. // ---------------------------------------------------------------------------
  150. void TPrefs::Write() //   
  151. // ---------------------------------------------------------------------------
  152. //  
  153. { 
  154.     FSSpec    fss;
  155.     OSErr    err;
  156.     short     fileRefNum;
  157.  
  158.  
  159.      if(fCollection )
  160.     {
  161.  
  162.          err = this->GetPrefSpec(&fss);
  163.  
  164.         if( err == fnfErr    )
  165.         {
  166.               err = this->CreatePrefFile(&fss);
  167.         }
  168.  
  169.         if(!err)
  170.         {
  171.  
  172.             Handle flattened = NewHandle(0);
  173.             SInt32 size;
  174.             SInt32 ByteCount;
  175.             
  176.             
  177.             ThrowIfMacErr( FSpOpenDF (&fss,fsWrPerm,&fileRefNum));
  178.  
  179.             err = FlattenCollectionToHdl(fCollection, flattened);
  180.             ByteCount = GetHandleSize(flattened);
  181.             
  182.             size = sizeof (SInt32);
  183.             FSWrite (fileRefNum, &size ,&ByteCount);
  184.             
  185.             size = ByteCount;
  186.             FSWrite (fileRefNum, &size ,*flattened);
  187.              
  188.              DisposeHandle(flattened);
  189.          
  190.               FSClose (fileRefNum);
  191.               
  192.             FlushVol (nil, fss.vRefNum);
  193.         }
  194.         
  195.     }
  196.  
  197.  
  198. }
  199.  
  200.  
  201.