src/mac/carbon/morefile/FullPath.c

   1 /*
   2         File:           FullPath.c
   3
   4         Contains:       Routines for dealing with full pathnames... if you really must.
   5
   6         Version:        MoreFiles
   7
   8         Copyright:      © 1995-2001 by Apple Computer, Inc., all rights reserved.
   9
  10         You may incorporate this sample code into your applications without
  11         restriction, though the sample code has been provided "AS IS" and the
  12         responsibility for its operation is 100% yours.  However, what you are
  13         not permitted to do is to redistribute the source as "DSC Sample Code"
  14         after having made changes. If you're going to re-distribute the source,
  15         we require that you make it clear in the source that the code was
  16         descended from Apple Sample Code, but that you've made changes.
  17
  18         File Ownership:
  19
  20                 DRI:                            Apple Macintosh Developer Technical Support
  21
  22                 Other Contact:          Apple Macintosh Developer Technical Support
  23                                                         <http://developer.apple.com/bugreporter/>
  24
  25                 Technology:                     DTS Sample Code
  26
  27         Writers:
  28
  29                 (JL)    Jim Luther
  30
  31         Change History (most recent first):
  32
  33                  <2>      2/7/01        JL              Added standard header. Updated names of includes.
  34                 <1>             12/06/99        JL              MoreFiles 1.5.
  35 */
  36
  37 #include <MacTypes.h>
  38 #include <MacErrors.h>
  39 #include <MacMemory.h>
  40 #include <Files.h>
  41 #include <TextUtils.h>
  42 #include <Aliases.h>
  43
  44 #define __COMPILINGMOREFILES
  45
  46 #include "FSpCompat.h"
  47 #include "FullPath.h"
  48
  49 /*
  50         IMPORTANT NOTE:
  51
  52         The use of full pathnames is strongly discouraged. Full pathnames are
  53         particularly unreliable as a means of identifying files, directories
  54         or volumes within your application, for two primary reasons:
  55
  56         ¥      The user can change the name of any element in the path at virtually
  57                 any time.
  58         ¥      Volume names on the Macintosh are *not* unique. Multiple
  59                 mounted volumes can have the same name. For this reason, the use of
  60                 a full pathname to identify a specific volume may not produce the
  61                 results you expect. If more than one volume has the same name and
  62                 a full pathname is used, the File Manager currently uses the first
  63                 mounted volume it finds with a matching name in the volume queue.
  64
  65         In general, you should use a fileÕs name, parent directory ID, and
  66         volume reference number to identify a file you want to open, delete,
  67         or otherwise manipulate.
  68
  69         If you need to remember the location of a particular file across
  70         subsequent system boots, use the Alias Manager to create an alias record
  71         describing the file. If the Alias Manager is not available, you can save
  72         the fileÕs name, its parent directory ID, and the name of the volume on
  73         which itÕs located. Although none of these methods is foolproof, they are
  74         much more reliable than using full pathnames to identify files.
  75
  76         Nonetheless, it is sometimes useful to display a fileÕs full pathname to
  77         the user. For example, a backup utility might display a list of full
  78         pathnames of files as it copies them onto the backup medium. Or, a
  79         utility might want to display a dialog box showing the full pathname of
  80         a file when it needs the userÕs confirmation to delete the file. No
  81         matter how unreliable full pathnames may be from a file-specification
  82         viewpoint, users understand them more readily than volume reference
  83         numbers or directory IDs. (Hint: Use the TruncString function from
  84         TextUtils.h with truncMiddle as the truncWhere argument to shorten
  85         full pathnames to a displayable length.)
  86
  87         The following technique for constructing the full pathname of a file is
  88         intended for display purposes only. Applications that depend on any
  89         particular structure of a full pathname are likely to fail on alternate
  90         foreign file systems or under future system software versions.
  91 */
  92
  93 /*****************************************************************************/
  94
  95 pascal  OSErr   GetFullPath(short vRefNum,
  96                                                         long dirID,
  97                                                         ConstStr255Param name,
  98                                                         short *fullPathLength,
  99                                                         Handle *fullPath)
 100 {
 101         OSErr           result;
 102         FSSpec          spec;
 103
 104         *fullPathLength = 0;
 105         *fullPath = NULL;
 106
 107         result = FSMakeFSSpecCompat(vRefNum, dirID, name, &spec);
 108         if ( (result == noErr) || (result == fnfErr) )
 109         {
 110                 result = FSpGetFullPath(&spec, fullPathLength, fullPath);
 111         }
 112
 113         return ( result );
 114 }
 115
 116 /*****************************************************************************/
 117
 118 pascal  OSErr   FSpGetFullPath(const FSSpec *spec,
 119                                                            short *fullPathLength,
 120                                                            Handle *fullPath)
 121 {
 122         OSErr           result;
 123         OSErr           realResult;
 124         FSSpec          tempSpec;
 125         CInfoPBRec      pb;
 126
 127         *fullPathLength = 0;
 128         *fullPath = NULL;
 129
 130
 131         /* Default to noErr */
 132         realResult = result = noErr;
 133
 134         /* work around Nav Services "bug" (it returns invalid FSSpecs with empty names) */
 135         if ( spec->name[0] == 0 )
 136         {
 137                 result = FSMakeFSSpecCompat(spec->vRefNum, spec->parID, spec->name, &tempSpec);
 138         }
 139         else
 140         {
 141                 /* Make a copy of the input FSSpec that can be modified */
 142                 BlockMoveData(spec, &tempSpec, sizeof(FSSpec));
 143         }
 144
 145         if ( result == noErr )
 146         {
 147                 if ( tempSpec.parID == fsRtParID )
 148                 {
 149                         /* The object is a volume */
 150
 151                         /* Add a colon to make it a full pathname */
 152                         ++tempSpec.name[0];
 153                         tempSpec.name[tempSpec.name[0]] = ':';
 154
 155                         /* We're done */
 156                         result = PtrToHand(&tempSpec.name[1], fullPath, tempSpec.name[0]);
 157                 }
 158                 else
 159                 {
 160                         /* The object isn't a volume */
 161
 162                         /* Is the object a file or a directory? */
 163                         pb.dirInfo.ioNamePtr = tempSpec.name;
 164                         pb.dirInfo.ioVRefNum = tempSpec.vRefNum;
 165                         pb.dirInfo.ioDrDirID = tempSpec.parID;
 166                         pb.dirInfo.ioFDirIndex = 0;
 167                         result = PBGetCatInfoSync(&pb);
 168                         // Allow file/directory name at end of path to not exist.
 169                         realResult = result;
 170                         if ( (result == noErr) || (result == fnfErr) )
 171                         {
 172                                 /* if the object is a directory, append a colon so full pathname ends with colon */
 173                                 if ( (result == noErr) && (pb.hFileInfo.ioFlAttrib & kioFlAttribDirMask) != 0 )
 174                                 {
 175                                         ++tempSpec.name[0];
 176                                         tempSpec.name[tempSpec.name[0]] = ':';
 177                                 }
 178
 179                                 /* Put the object name in first */
 180                                 result = PtrToHand(&tempSpec.name[1], fullPath, tempSpec.name[0]);
 181                                 if ( result == noErr )
 182                                 {
 183                                         /* Get the ancestor directory names */
 184                                         pb.dirInfo.ioNamePtr = tempSpec.name;
 185                                         pb.dirInfo.ioVRefNum = tempSpec.vRefNum;
 186                                         pb.dirInfo.ioDrParID = tempSpec.parID;
 187                                         do      /* loop until we have an error or find the root directory */
 188                                         {
 189                                                 pb.dirInfo.ioFDirIndex = -1;
 190                                                 pb.dirInfo.ioDrDirID = pb.dirInfo.ioDrParID;
 191                                                 result = PBGetCatInfoSync(&pb);
 192                                                 if ( result == noErr )
 193                                                 {
 194                                                         /* Append colon to directory name */
 195                                                         ++tempSpec.name[0];
 196                                                         tempSpec.name[tempSpec.name[0]] = ':';
 197
 198                                                         /* Add directory name to beginning of fullPath */
 199                                                         (void) Munger(*fullPath, 0, NULL, 0, &tempSpec.name[1], tempSpec.name[0]);
 200                                                         result = MemError();
 201                                                 }
 202                                         } while ( (result == noErr) && (pb.dirInfo.ioDrDirID != fsRtDirID) );
 203                                 }
 204                         }
 205                 }
 206         }
 207
 208         if ( result == noErr )
 209         {
 210                 /* Return the length */
 211                 *fullPathLength = GetHandleSize(*fullPath);
 212                 result = realResult;    // return realResult in case it was fnfErr
 213         }
 214         else
 215         {
 216                 /* Dispose of the handle and return NULL and zero length */
 217                 if ( *fullPath != NULL )
 218                 {
 219                         DisposeHandle(*fullPath);
 220                 }
 221                 *fullPath = NULL;
 222                 *fullPathLength = 0;
 223         }
 224
 225         return ( result );
 226 }
 227
 228 /*****************************************************************************/
 229
 230 pascal OSErr FSpLocationFromFullPath(short fullPathLength,
 231                                                                          const void *fullPath,
 232                                                                          FSSpec *spec)
 233 {
 234         AliasHandle     alias;
 235         OSErr           result;
 236         Boolean         wasChanged;
 237         Str32           nullString;
 238
 239         /* Create a minimal alias from the full pathname */
 240         nullString[0] = 0;      /* null string to indicate no zone or server name */
 241         result = NewAliasMinimalFromFullPath(fullPathLength, fullPath, nullString, nullString, &alias);
 242         if ( result == noErr )
 243         {
 244                 /* Let the Alias Manager resolve the alias. */
 245                 result = ResolveAlias(NULL, alias, spec, &wasChanged);
 246
 247                 /* work around Alias Mgr sloppy volume matching bug */
 248                 if ( spec->vRefNum == 0 )
 249                 {
 250                         /* invalidate wrong FSSpec */
 251                         spec->parID = 0;
 252                         spec->name[0] =  0;
 253                         result = nsvErr;
 254                 }
 255                 DisposeHandle((Handle)alias);   /* Free up memory used */
 256         }
 257         return ( result );
 258 }
 259
 260 /*****************************************************************************/
 261
 262 pascal OSErr LocationFromFullPath(short fullPathLength,
 263                                                                   const void *fullPath,
 264                                                                   short *vRefNum,
 265                                                                   long *parID,
 266                                                                   Str31 name)
 267 {
 268         OSErr   result;
 269         FSSpec  spec;
 270
 271         result = FSpLocationFromFullPath(fullPathLength, fullPath, &spec);
 272         if ( result == noErr )
 273         {
 274                 *vRefNum = spec.vRefNum;
 275                 *parID = spec.parID;
 276                 BlockMoveData(&spec.name[0], &name[0], spec.name[0] + 1);
 277         }
 278         return ( result );
 279 }
 280
 281 /*****************************************************************************/
 282