In message <1490297671.58015.102.ca...@freebsd.org>, Ian Lepore writes:
> On Thu, 2017-03-23 at 19:58 +0100, Roman Divacky wrote:
> > On Thu, Mar 23, 2017 at 02:36:51AM +0000, Warner Losh wrote:
> > >
> > > Author: imp
> > > Date: Thu Mar 23 02:36:51 2017
> > > New Revision: 315773
> > > URL: https://svnweb.freebsd.org/changeset/base/315773
> > >
> > > Log:
> > > Â Implement quote escaping. String values may now contain " if you
> > > Â it is preceded by \.
> > > Â Â
> > > Â foo="I \"like\" C++"
> > > Â Â
> > > Â gives the value 'I "like" C++' to the variable 'foo'. If a
> > > character
> > > Â other than " follows the \, both the \ and that character are
> > > passed
> > > Â through.
> > > Â Â
> > > Â Differential Revision: https://reviews.freebsd.org/D6286
> > > Â Sponsored by: Netflix
> > >
> > > Modified:
> > > Â head/sbin/devd/devd.cc
> > > Â head/sbin/devd/devd.hh
> > >
> > > Modified: head/sbin/devd/devd.cc
> > > ===================================================================
> > > ===========
> > > --- head/sbin/devd/devd.cc Thu Mar 23 02:33:27 2017 (
> > > r315772)
> > > +++ head/sbin/devd/devd.cc Thu Mar 23 02:36:51 2017 (
> > > r315773)
> > > @@ -411,6 +411,32 @@ var_list::is_set(const string &var) cons
> > > Â return (_vars.find(var) != _vars.end());
> > > Â }
> > > Â
> > > +/** fix_value
> > > + *
> > > + * Removes quoted characters that have made it this far. \" are
> > > + * converted to ". For all other characters, both \ and following
> > > + * character. So the string 'fre\:\"' is translated to 'fred\:"'.
> > > + */
> > > +const std::string &
> > > +var_list::fix_value(const std::string &val) const
> > > +{
> > > + char *tmp, *dst;
> > > + const char *src;
> > > + std::string *rv;
> > > +
> > > + dst = tmp = new char[val.length()];
> > > + src = val.c_str();
> > > + while (*src) {
> > > + if (*src == '\\' && src[1] == '"')
> > > + src++;
> > > + else
> > > + *dst++ = *src++;
> > > + }
> > > + rv = new string(tmp);
> > > + delete tmp;
> > > + return *rv;
> > > +}
> > Can the temporary char[] be stack allocated? Also, when returning a
> > reference to
> > a heap allocated string who is responsible for freeing it? Perhaps
> > you can just
> > return std::string and let the compiler optimize it?
> >
> > Roman
> >
>
> Returning a reference to a new'd string is not good.
>
> IMO, the implementation of the function should take into account the
> idea that embedded escaped quotes are rare. Â The function should be
> optimized for readability and the common case of simply copying the
> string unmodified, something like:
>
>
> std::string
> var_list::fix_value(const std::string &val) const
> {
> std::string rv(val);
> std::string::size_type pos(0);
>
> while ((pos = rv.find("\\\"", pos)) != rv.npos) {
> rv.erase(pos, 1);
> }
> return (rv);
> }
This revision caused devd a little gas. It failed to start moused for usb
attached mice (ums0 & ums1) to my latpop and nut failed to recognize my USB
connected UPS on a server. downstairs due to a permission issue which nut
provides a devd.conf file with:
chgrp uucp /dev/$cdev; chmod g+rw /dev/$cdev
--
Cheers,
Cy Schubert <cy.schub...@cschubert.com>
FreeBSD UNIX: <c...@freebsd.org> Web: http://www.FreeBSD.org
The need of the many outweighs the greed of the few.
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