[lldb-dev] Backslashes in command arguments

Mon Jan 12 14:59:25 PST 2015

Probably the command interpreter, but we have all the command interpreter settings on the debugger right now anyway, so don't change anything on that end..

> On Jan 12, 2015, at 2:35 PM, Zachary Turner <zturner at google.com> wrote:
> 
> Thanks for the response.  By the way, is this setting more appropriate on the CommandInterpreter instead of the debugger?
> 
> On Mon Jan 12 2015 at 2:34:06 PM Greg Clayton <gclayton at apple.com> wrote:
> 
> > On Jan 12, 2015, at 2:05 PM, Zachary Turner <zturner at google.com> wrote:
> >
> > There doesn't seem to be a good way to get access to the Debugger object from the Args class.  I tried changing Args to take a Debugger to its constructor, but it seems this isn't always possible, for example with anything having to do with OptionValue.
> > I could provide a default value of NULL for the Debugger, and if NULL it would fall back to the default escape character, but this seems awkward.
> >
> > Since I've declared this as a global property, why should I even need a Debugger instance?  Shouldn't the global settings be static on the Debugger so that they can be accessed without an instance?
> 
> 
> This is the problem. See how process does it:
> 
> class Process {
>     static const ProcessPropertiesSP &
>     GetGlobalProperties();
> }
> 
> The debugger should do the same thing. It should also add static accessors for all of the settings that are truly global settings. Looking at the global settings, they all seem to be set to be global values which probably isn't what we want. Why? Xcode creates a new Debugger for each debugging window that it creates and if someone types "setting set auto-confirm false" in one command interpreter, it shouldn't affect the other.
> 
> So I would say we need to switch all debugger settings to be non-global (third initialized in each of the PropertyDefinition values should be set to "false" in g_properties in Debugger.cpp) and the only one that should remain global is your new escape character. Then Debugger should get a new static accessor:
> 
> class Debugger
> {
>     static char
>     GetEscapeCharacter();
> };
> 
> This in turn will access the global properties and return it to outside folks.
> 
> Check out the ProcessProperties class in Process.h and check out its constructor. We will need to do something similar for the debugger's settings. Right now Debugger inherits directly from Properties, but we will need to change it to be like the process where there is a DebuggerProperties class. The global version gets constructed with a "bool is_global" set to false, and the instance ones get constructed with that set to true.
> 
> The Process class is the model we will need to follow if you want to make this change and have a true global property that can be accessed without a Debugger instance.
> 
> 
> >
> > On Thu Jan 08 2015 at 3:00:30 PM <jingham at apple.com> wrote:
> > It's not just file names, you would also have to make sure there's nothing else that might be in command argument or option value that has a single & a double quote, since without the backslashes this would be impossible.
> >
> > If you really want to do this, I think it would be better to add a debugger setting for the "protection character".  Then this would be set to something else (maybe "#") on Windows, and backslash on all other systems.  That way you could probably always find a protection character that you could use for whatever gnarly string you ended up having to pass through the command interpreter.
> >
> > Jim
> >
> >
> > > On Jan 8, 2015, at 2:55 PM, Zachary Turner <zturner at google.com> wrote:
> > >
> > > Actually ' is a valid filename character in Windows, but not ".  That being said, it's so rare, and having a backslash is so common that I would prefer the common case to be easy, and the rare case being either unsupported or difficult is ok with me.  So I'd still prefer to disable this backslash handling on Windows for now, and then fix ' on Windows separately in the future.
> > >
> > > On Thu Jan 08 2015 at 2:51:51 PM Zachary Turner <zturner at google.com> wrote:
> > > On Windows, that's not a valid file name, and in fact any file name that has an escaped character is not a valid filename.  I see what you're getting at though, that for non-Windows it's necessary.  Can I wrap the backslash handling in #ifndef _WIN32 then?
> > >
> > > On Thu Jan 08 2015 at 2:49:49 PM <jingham at apple.com> wrote:
> > > If I have a file called foo"bar'baz, how what would I put in the place of <AWKWARD NAME> for
> > >
> > > (lldb) file <AWKWARD NAME>
> > >
> > > Right now, I can do:
> > >
> > > (lldb) file foo\"bar\'baz
> > > Current executable set to 'foo"bar'baz' (x86_64).
> > >
> > > Jim
> > >
> > >
> > > > On Jan 8, 2015, at 2:31 PM, Zachary Turner <zturner at google.com> wrote:
> > > >
> > > > FWIW, Removing backslash handling from this function (essentially ignoring backslashes in command arguments) fixes about 12-15 tests on Windows with no other changes.  I see there's some logic in Args for encoding and decoding escape sequences, but this only happens if a particular command option is set, and that command only only appears to be set for the "prompt" command.  I'm not sure if removing the backslash logic from SetCommandString would interfere with this command in any way, but it doesn't seem like it would interfere with any other commands, unless I'm missing something.
> > > >
> > > > On Thu Jan 08 2015 at 1:43:16 PM Zachary Turner <zturner at google.com> wrote:
> > > > One thing causing many tests to fail on Windows is the presence of backslashes in argument.  Until now, I've worked around this in many cases by making sure that arguments with backslashes are always quoted.
> > > >
> > > > But there are some cases where this is not easy to guarantee and now I'm leaning towards (at least on Windows) allowing backslashes in argument strings.  The code in question comes from the function void SetCommandString (const char *command) in the file Args.cpp
> > > >
> > > > In particular, it implements special handling of whitespace, single quotes, double quotes, and backslashes.  For the case of backslashes it removes them from the string.
> > > >
> > > > What would be the implications of removing backslash handling from this function for all platforms?  I would prefer to keep platform specific code out of generic code, but I think this needs to be changed on Windows.
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