Sources/FullPath.c

/*
    File:       FullPath.c
 
    Contains:   Routines for dealing with full pathnames... if you really must.
 
    Version:    MoreFiles
 
    Copyright:  © 1995-2002 by Apple Computer, Inc., all rights reserved.
 
    Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Computer, Inc.
                ("Apple") in consideration of your agreement to the following terms, and your
                use, installation, modification or redistribution of this Apple software
                constitutes acceptance of these terms.  If you do not agree with these terms,
                please do not use, install, modify or redistribute this Apple software.
 
                In consideration of your agreement to abide by the following terms, and subject
                to these terms, Apple grants you a personal, non-exclusive license, under AppleÕs
                copyrights in this original Apple software (the "Apple Software"), to use,
                reproduce, modify and redistribute the Apple Software, with or without
                modifications, in source and/or binary forms; provided that if you redistribute
                the Apple Software in its entirety and without modifications, you must retain
                this notice and the following text and disclaimers in all such redistributions of
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                Apple Computer, Inc. may be used to endorse or promote products derived from the
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                expressly stated in this notice, no other rights or licenses, express or implied,
                are granted by Apple herein, including but not limited to any patent rights that
                may be infringed by your derivative works or by other works in which the Apple
                Software may be incorporated.
 
                The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO
                WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED
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                PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN
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                IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR
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    File Ownership:
 
        DRI:                Apple Macintosh Developer Technical Support
 
        Other Contact:      Apple Macintosh Developer Technical Support
                            <http://developer.apple.com/bugreporter/>
 
        Technology:         DTS Sample Code
 
    Writers:
 
        (JL)    Jim Luther
 
    Change History (most recent first):
 
         <4>     8/23/02    JL      [2853901]  Updated standard disclaimer.
         <3>      7/6/01    JL      [2661720]  Make comments ANSI C compliant.
         <2>      2/7/01    JL      Added standard header. Updated names of includes.
        <1>     12/06/99    JL      MoreFiles 1.5.
*/
 
#include <MacTypes.h>
#include <MacErrors.h>
#include <MacMemory.h>
#include <Files.h>
#include <TextUtils.h>
#include <Aliases.h>
 
#define __COMPILINGMOREFILES
 
#include "FSpCompat.h"
#include "FullPath.h"
 
/*
    IMPORTANT NOTE:
    
    The use of full pathnames is strongly discouraged. Full pathnames are
    particularly unreliable as a means of identifying files, directories
    or volumes within your application, for two primary reasons:
    
    ¥   The user can change the name of any element in the path at virtually
        any time.
    ¥   Volume names on the Macintosh are *not* unique. Multiple
        mounted volumes can have the same name. For this reason, the use of
        a full pathname to identify a specific volume may not produce the
        results you expect. If more than one volume has the same name and
        a full pathname is used, the File Manager currently uses the first
        mounted volume it finds with a matching name in the volume queue.
    
    In general, you should use a fileÕs name, parent directory ID, and
    volume reference number to identify a file you want to open, delete,
    or otherwise manipulate.
    
    If you need to remember the location of a particular file across
    subsequent system boots, use the Alias Manager to create an alias record
    describing the file. If the Alias Manager is not available, you can save
    the fileÕs name, its parent directory ID, and the name of the volume on
    which itÕs located. Although none of these methods is foolproof, they are
    much more reliable than using full pathnames to identify files.
    
    Nonetheless, it is sometimes useful to display a fileÕs full pathname to
    the user. For example, a backup utility might display a list of full
    pathnames of files as it copies them onto the backup medium. Or, a
    utility might want to display a dialog box showing the full pathname of
    a file when it needs the userÕs confirmation to delete the file. No
    matter how unreliable full pathnames may be from a file-specification
    viewpoint, users understand them more readily than volume reference
    numbers or directory IDs. (Hint: Use the TruncString function from
    TextUtils.h with truncMiddle as the truncWhere argument to shorten
    full pathnames to a displayable length.)
    
    The following technique for constructing the full pathname of a file is
    intended for display purposes only. Applications that depend on any
    particular structure of a full pathname are likely to fail on alternate
    foreign file systems or under future system software versions.
*/
 
/*****************************************************************************/
 
pascal  OSErr   GetFullPath(short vRefNum,
                            long dirID,
                            ConstStr255Param name,
                            short *fullPathLength,
                            Handle *fullPath)
{
    OSErr       result;
    FSSpec      spec;
    
    *fullPathLength = 0;
    *fullPath = NULL;
    
    result = FSMakeFSSpecCompat(vRefNum, dirID, name, &spec);
    if ( (result == noErr) || (result == fnfErr) )
    {
        result = FSpGetFullPath(&spec, fullPathLength, fullPath);
    }
    
    return ( result );
}
 
/*****************************************************************************/
 
pascal  OSErr   FSpGetFullPath(const FSSpec *spec,
                               short *fullPathLength,
                               Handle *fullPath)
{
    OSErr       result;
    OSErr       realResult;
    FSSpec      tempSpec;
    CInfoPBRec  pb;
    
    *fullPathLength = 0;
    *fullPath = NULL;
    
    
    /* Default to noErr */
    realResult = result = noErr;
    
    /* work around Nav Services "bug" (it returns invalid FSSpecs with empty names) */
    if ( spec->name[0] == 0 )
    {
        result = FSMakeFSSpecCompat(spec->vRefNum, spec->parID, spec->name, &tempSpec);
    }
    else
    {
        /* Make a copy of the input FSSpec that can be modified */
        BlockMoveData(spec, &tempSpec, sizeof(FSSpec));
    }
    
    if ( result == noErr )
    {
        if ( tempSpec.parID == fsRtParID )
        {
            /* The object is a volume */
            
            /* Add a colon to make it a full pathname */
            ++tempSpec.name[0];
            tempSpec.name[tempSpec.name[0]] = ':';
            
            /* We're done */
            result = PtrToHand(&tempSpec.name[1], fullPath, tempSpec.name[0]);
        }
        else
        {
            /* The object isn't a volume */
            
            /* Is the object a file or a directory? */
            pb.dirInfo.ioNamePtr = tempSpec.name;
            pb.dirInfo.ioVRefNum = tempSpec.vRefNum;
            pb.dirInfo.ioDrDirID = tempSpec.parID;
            pb.dirInfo.ioFDirIndex = 0;
            result = PBGetCatInfoSync(&pb);
            /* Allow file/directory name at end of path to not exist. */
            realResult = result;
            if ( (result == noErr) || (result == fnfErr) )
            {
                /* if the object is a directory, append a colon so full pathname ends with colon */
                if ( (result == noErr) && (pb.hFileInfo.ioFlAttrib & kioFlAttribDirMask) != 0 )
                {
                    ++tempSpec.name[0];
                    tempSpec.name[tempSpec.name[0]] = ':';
                }
                
                /* Put the object name in first */
                result = PtrToHand(&tempSpec.name[1], fullPath, tempSpec.name[0]);
                if ( result == noErr )
                {
                    /* Get the ancestor directory names */
                    pb.dirInfo.ioNamePtr = tempSpec.name;
                    pb.dirInfo.ioVRefNum = tempSpec.vRefNum;
                    pb.dirInfo.ioDrParID = tempSpec.parID;
                    do  /* loop until we have an error or find the root directory */
                    {
                        pb.dirInfo.ioFDirIndex = -1;
                        pb.dirInfo.ioDrDirID = pb.dirInfo.ioDrParID;
                        result = PBGetCatInfoSync(&pb);
                        if ( result == noErr )
                        {
                            /* Append colon to directory name */
                            ++tempSpec.name[0];
                            tempSpec.name[tempSpec.name[0]] = ':';
                            
                            /* Add directory name to beginning of fullPath */
                            (void) Munger(*fullPath, 0, NULL, 0, &tempSpec.name[1], tempSpec.name[0]);
                            result = MemError();
                        }
                    } while ( (result == noErr) && (pb.dirInfo.ioDrDirID != fsRtDirID) );
                }
            }
        }
    }
    
    if ( result == noErr )
    {
        /* Return the length */
        *fullPathLength = GetHandleSize(*fullPath);
        result = realResult;    /* return realResult in case it was fnfErr */
    }
    else
    {
        /* Dispose of the handle and return NULL and zero length */
        if ( *fullPath != NULL )
        {
            DisposeHandle(*fullPath);
        }
        *fullPath = NULL;
        *fullPathLength = 0;
    }
    
    return ( result );
}
 
/*****************************************************************************/
 
pascal OSErr FSpLocationFromFullPath(short fullPathLength,
                                     const void *fullPath,
                                     FSSpec *spec)
{
    AliasHandle alias;
    OSErr       result;
    Boolean     wasChanged;
    Str32       nullString;
    
    /* Create a minimal alias from the full pathname */
    nullString[0] = 0;  /* null string to indicate no zone or server name */
    result = NewAliasMinimalFromFullPath(fullPathLength, fullPath, nullString, nullString, &alias);
    if ( result == noErr )
    {
        /* Let the Alias Manager resolve the alias. */
        result = ResolveAlias(NULL, alias, spec, &wasChanged);
        
        /* work around Alias Mgr sloppy volume matching bug */
        if ( spec->vRefNum == 0 )
        {
            /* invalidate wrong FSSpec */
            spec->parID = 0;
            spec->name[0] =  0;
            result = nsvErr;
        }
        DisposeHandle((Handle)alias);   /* Free up memory used */
    }
    return ( result );
}
 
/*****************************************************************************/
 
pascal OSErr LocationFromFullPath(short fullPathLength,
                                  const void *fullPath,
                                  short *vRefNum,
                                  long *parID,
                                  Str31 name)
{
    OSErr   result;
    FSSpec  spec;
    
    result = FSpLocationFromFullPath(fullPathLength, fullPath, &spec);
    if ( result == noErr )
    {
        *vRefNum = spec.vRefNum;
        *parID = spec.parID;
        BlockMoveData(&spec.name[0], &name[0], spec.name[0] + 1);
    }
    return ( result );
}
 
/*****************************************************************************/