Re: [PATCH v5 02/32] lib/string_helpers: Convert string_escape_mem() to printbuf

[Kent Overstreet]

On 8/8/22 08:03, Andy Shevchenko wrote:
> On Mon, Aug 8, 2022 at 4:41 AM Matthew Wilcox (Oracle)
> <willy@xxxxxxxxxxxxx> wrote:
> > From: Kent Overstreet <kent.overstreet@xxxxxxxxx>
> >
> > Like the upcoming vsprintf.c conversion, this converts string_escape_mem
> > to prt_escaped_string(), which uses and outputs to a printbuf, and makes
> > string_escape_mem() a smaller wrapper to support existing users.
> >
> > The new printbuf helpers greatly simplify the code.
>
> ...
>
> >   struct device;
> >   struct file;
> >   struct task_struct;
> > +struct printbuf;
>
> Keep it ordered?

I generally try to keep my #includes alphabetized, missed this :)

> ...
>
> > @@ -71,6 +74,7 @@ static inline int string_escape_mem_any_np(const char *src, size_t isz,
> >          return string_escape_mem(src, isz, dst, osz, ESCAPE_ANY_NP, only);
> >   }
> >
> > +
> >   static inline int string_escape_str(const char *src, char *dst, size_t sz,
> >                  unsigned int flags, const char *only)
> >   {
>
> Stray change.

Fixed

> ...
>
> >                  if (!(is_append || in_dict) && is_dict &&
> > -                                         escape_passthrough(c, &p, end))
> > +                   escape_passthrough(out, c))
>
> That (a bit strange) indentation is on purpose. Can we keep it?

Yep, done

> >                          continue;
>
> ...
>
> Not sure if the below was in the original text, but maybe it makes
> sense to amend.
>
> > + * Description:
> > + * The process of escaping byte buffer includes several parts. They are applied
>
> a byte in the buffer (?)

See below

> > + * in the following sequence.
> > + *
> > + *     1. The character is not matched to the one from @only string and thus
> > + *        must go as-is to the output.
> > + *     2. The character is matched to the printable and ASCII classes, if asked,
> > + *        and in case of match it passes through to the output.
> > + *     3. The character is matched to the printable or ASCII class, if asked,
> > + *        and in case of match it passes through to the output.
> > + *     4. The character is checked if it falls into the class given by @flags.
> > + *        %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any
> > + *        character. Note that they actually can't go together, otherwise
> > + *        %ESCAPE_HEX will be ignored.
> > + *
> > + * Caller must provide valid source and destination pointers. Be aware that
> > + * destination buffer will not be NULL-terminated, thus caller have to append
>
> the caller has

Yeah I'm actually not changing the function comment for 
string_escape_mem(), that's just git getting confused since I reused 
most of it for prt_escaped_mem(). I'll leave any fixups for that for you 
if that's ok - the docs look clear enough to me.

Cheers