Re: Odd problem with NSSavePanel

[Fred Kiefer]

Should be fixed now. Please give it a try.

Fred

On 10.01.2014 16:50, Fred Kiefer wrote:
> Hi German,
> 
> I think I understand the problem now and it is only in NSSavePenl, not
> in your application. When the save panel has already been used it holds
> a value in the instance variable _fullFileName. When a document without
> a name gets save the save panel method runModal gets called, which calls
> [self filename] which sometimes just returns _fullFileName. Next [self
> _setupForDirectory: path file: filename] gets called with this value and
> the this line resets the instance variable:
> 
> ASSIGN(_fullFileName, [_directory stringByAppendingPathComponent:
> filename]);
> 
> Now as filename is actually _fullFileName it will get released and any
> usage of this variable later on will lead to the segmentation fault you
> are getting. And this happens just two lines later.
> 
> Now the correct solution is to return an autorelease copy from the
> filename method, as I already expected. But one other questions gets
> raised by this, where should we use file names including directories and
> where just a simple file name? This seems to be wrong as well.
> 
> Fred
> 
> On 09.01.2014 09:15, Fred Kiefer wrote:
>> Hi German,
>>
>> I did some investigations into this myself but didn't write about it,
>> as I couldn't pin down the issue. I don't think the filename is empty
>> when the code crashes. Rather it is filled with an already released
>> value. You may check that in gbd, the variable has a value but
>> dereferencing it crashes gdb. Most likely the release happens outside
>> of the save panel, otherwise we would have the problem with all
>> document applications. At least we should protect the save panel
>> against this by returning a copy from that method. I hope to find
>> time for this tomorrow.
>>
>> Fred
>>
>> On the road
>>
>> Am 09.01.2014 um 08:07 schrieb Germán Arias <address@hidden>:
>>
>>> Well, after some research I'm more confused. I'm not sure, but I
>>> think that _fullFileName and _allowedFileTypes are involved in
>>> this problem. At some moment these variables don't store anything.
>>> So, the method -filename don't return anything, and call -length
>>> over the returned value crashed the program.
>>>
>>> The other problem I see is that _fullFileName depends of returned
>>> value from -filename. You can see this at line 608 on
>>> NSSavePanel.m. The parameter filename is the returned value of
>>> -filename (see method -runModal). At line 608, what happen when
>>> pass a parameter that don't contains anything?
>>>
>>> Furthermore, I noticed other strange problem with SavePanel. For
>>> example: launch Ink, write something at the document and save this.
>>> Now close the document and creates a new one. Write something in
>>> this new document and save this. If you notice, the save panel puts
>>> the full path of previous saved document. See attached image. Why
>>> do this the panel?
>>>
>>> <savepanel.jpg>
>>>
>>>
>>>> On 2014-01-07 12:45:58 -0600 Germán Arias <address@hidden>
>>>> wrote:
>>>>
>>>> I'm having a problem with Gemas and NSSavePanel. You can
>>>> reproduce it with these steps:
>>>>
>>>> * Launch Gemas. * Create a new file of type "Other" (Document ->
>>>> New File -> Other). * Write something. * Save the file (don't add
>>>> an extension). * Close the document. * Create a new file of type
>>>> "Other". * Write something. * Try to save this, the app crash.
>>>>
>>>> At GemasInfo.plist the extension of this type is described as ( *
>>>> ), this is any file. And this problem only occurs with types that
>>>> have its extension like this one.
>>>>
>>>> Here the backtrace:
>>>>
>>>> (gdb) backtrace #0  0x00a992c6 in objc_msg_lookup () from
>>>> /usr/lib/i386-linux-gnu/libobjc.so.3 #1  0x0032866b in
>>>> -[NSSavePanel(PrivateMethods) _selectCellName:] ( self=0x82bfa28,
>>>> _cmd=0x55f520, title=0x8548ea0) at NSSavePanel.m:528 #2
>>>> 0x00328af5 in -[NSSavePanel(PrivateMethods) _setFileName:] ( 
>>>> self=0x82bfa28, _cmd=0x55f588, filename=0x8548ea0) at
>>>> NSSavePanel..m:587 #3  0x00328d13 in
>>>> -[NSSavePanel(PrivateMethods) _setupForDirectory:file:] ( 
>>>> self=0x82bfa28, _cmd=0x55f1b0, path=0x821c928,
>>>> filename=0x8548ea0) at NSSavePanel.m:610 #4  0x00329c8d in
>>>> -[NSSavePanel runModalForDirectory:file:] (self=0x82bfa28, 
>>>> _cmd=0x55f6a0, path=0x821c928, filename=0x8548ea0) at
>>>> NSSavePanel..m:1140 #5  0x00329ba6 in -[NSSavePanel runModal]
>>>> (self=0x82bfa28, _cmd=0x518e10) at NSSavePanel.m:1111 #6
>>>> 0x00285fbb in -[NSDocument runModalSavePanel:withAccessoryView:]
>>>> ( self=0x837c278, _cmd=0x518ef0, savePanel=0x82bfa28, 
>>>> accessoryView=0x84c4f68) at NSDocument.m:1088 #7  0x00289be7 in
>>>> -[NSDocument _runSavePanelForSaveOperation:] ( self=0x837c278,
>>>> _cmd=0x518ef8, saveOperation=NSSaveOperation) at
>>>> NSDocument.m:1203 #8  0x00286319 in -[NSDocument 
>>>> runModalSavePanelForSaveOperation:delegate:didSaveSelector:contextInfo:]
>>>>  (self=0x837c278, _cmd=0x519020, saveOperation=NSSaveOperation,
>>>> delegate=0x0, didSaveSelector=0x0, contextInfo=0x0) at
>>>> NSDocument.m:1229 #9  0x0028745d in -[NSDocument 
>>>> saveDocumentWithDelegate:didSaveSelector:contextInfo:]
>>>> (self=0x837c278, _cmd=0x519018, delegate=0x0,
>>>> didSaveSelector=0x0, ---Type <return> to continue, or q <return>
>>>> to quit--- contextInfo=0x0) at NSDocument.m:1564 #10 0x002872c1
>>>> in -[NSDocument saveDocument:] (self=0x837c278, _cmd=0x8147910, 
>>>> sender=0x83080e0) at NSDocument.m:1524 #11 0x0020ce97 in
>>>> -[NSApplication sendAction:to:from:] (self=0x81253f8, 
>>>> _cmd=0x53ef50, aSelector=0x8147910, aTarget=0x0,
>>>> sender=0x83080e0) at NSApplication.m:2230 #12 0x002e2c64 in
>>>> -[NSMenu performActionForItemAtIndex:] (self=0x8302618, 
>>>> _cmd=0x5420a0, index=4) at NSMenu.m:1323 #13 0x002ecb6a in
>>>> -[NSMenuView _trackWithEvent:startingMenuView:] ( self=0x8309300,
>>>> _cmd=0x542118, event=<optimized out>, mainWindowMenuView=0x0) at
>>>> NSMenuView.m:1916 #14 0x002eb113 in -[NSMenuView trackWithEvent:]
>>>> (self=0x8309300, _cmd=0x542188, event=0x833e558) at
>>>> NSMenuView.m:1948 #15 0x002eb414 in -[NSMenuView mouseDown:]
>>>> (self=0x8309300, _cmd=0x59fff0, theEvent=0x833e558) at
>>>> NSMenuView.m:1988 #16 0x003d6724 in -[NSWindow sendEvent:]
>>>> (self=0x8308630, _cmd=0x4eaf40, theEvent=0x833e558) at
>>>> NSWindow.m:3896 #17 0x00211f7b in -[NSApplication sendEvent:]
>>>> (self=0x81253f8, _cmd=0x4eae78, theEvent=0x833e558) at
>>>> NSApplication.m:2105 #18 0x002144eb in -[NSApplication run]
>>>> (self=0x81253f8, _cmd=0x4e1348) at NSApplication.m:1562 #19
>>>> 0x001f1f0f in NSApplicationMain (argc=1, argv=0xbfffe404) at 
>>>> Functions.m:91 #20 0x08048fe7 in main (argc=1, argv=0xbfffe404)
>>>> at Gemas_main.m:26
>>>>
>>>> Any advice?
>>>>
>>>> Thanks. Germán.