Re: [toolbox] aliases vs. paths (was: Extended Attributes)

[<jer...@u-...>]

Le 6 juil. 05, =E0 17:54, Maxwell, Adam R a =E9crit :

>
> On Jul 6, 2005, at 08:16, Jon Guyer wrote:
>
>>
>> On Jul 6, 2005, at 10:18 AM, J=E9r=F4me Laurens wrote:
>>
>>
>>> What will happen if I duplicate a file, for example by copying it on =
=20
>>> a USB memory key, then copy it on my home computer, then copy it =20
>>> back. What is the location pointed to by the alias? It might be =20
>>> consistent but not correct.
>>> This is an example where the path can be correct but the alias can =20=

>>> be broken.
>>> On the other hand, changing a file name will break the stored path =20=

>>> but not the alias.
>>>
>>
>> Aliases can be relative =20
>> <http://developer.apple.com/samplecode/resolveRelativeAlias/=20
>> resolveRelativeAlias.html>
>
> Or if you don't grok Pascal (or whatever that sample is :)...
>
> <http://developer.apple.com/documentation/MacOSX/Conceptual/=20
> BPFileSystem/Concepts/Aliases.html> has some info on relative paths =20=

> vs. aliases.
>
> If you're using Cocoa, BDAlias is useful for working with aliases and =20=

> paths, especially for serializing aliases: =20
> <http://bdistributed.com/Projects/BDAlias/>.
>
> My own view is that hard-coded paths in plists and code are evil, =20
> whether they are paths to a recent file, Application Support, =20
> Preferences, or a temp directory.
>
> -- Adam
>
>

could not get this to work:

create a new cocoa application project, add BDAlias, and use the =20
following main

int main(int argc, char *argv[])
{
     return NSApplicationMain(argc, argv);
}

#import "BDAlias.h"
static id textField;
@implementation NSApplication(h)
- (void) setTextField: (id) sender;
{
     textField =3D sender;
}
- (IBAction) createRelativeAlias: (id) sender;
{
     NSOpenPanel * OP =3D [NSOpenPanel openPanel];
     [OP setAllowsMultipleSelection:NO];
     [OP setCanChooseDirectories: NO];
     if ([OP runModalForTypes:nil] =3D=3D NSOKButton)
     {
         NSString *target =3D [[OP filenames] lastObject];
         BDAlias * alias =3D [BDAlias aliasWithPath: [target =20
lastPathComponent] relativeToPath: [target =20
stringByDeletingLastPathComponent]];
         [textField setStringValue: [alias fullPathRelativeToPath: =20
NSHomeDirectory()]];
     }
}
@end


In the nib, subclass the NSApplication to add a createRelativeAlias: =20
message, and a textField outlet.
Make the owner an instance of this class.

Run the app. The alias created does not take into account the =20
NSHomeDirectory()/Documents as absolute reference.

Things are complicated.=