Re: [PATCH v2 03/17] kunit: test: add string_stream a std::stream like string builder

[Brendan Higgins]

On Thu, May 2, 2019 at 6:26 PM shuah <shuah@xxxxxxxxxx> wrote:
>
> On 5/1/19 5:01 PM, Brendan Higgins wrote:
< snip >
> > diff --git a/kunit/Makefile b/kunit/Makefile
> > index 5efdc4dea2c08..275b565a0e81f 100644
> > --- a/kunit/Makefile
> > +++ b/kunit/Makefile
> > @@ -1 +1,2 @@
> > -obj-$(CONFIG_KUNIT) +=                       test.o
> > +obj-$(CONFIG_KUNIT) +=                       test.o \
> > +                                     string-stream.o
> > diff --git a/kunit/string-stream.c b/kunit/string-stream.c
> > new file mode 100644
> > index 0000000000000..7018194ecf2fa
> > --- /dev/null
> > +++ b/kunit/string-stream.c
> > @@ -0,0 +1,144 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * C++ stream style string builder used in KUnit for building messages.
> > + *
> > + * Copyright (C) 2019, Google LLC.
> > + * Author: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
> > + */
> > +
> > +#include <linux/list.h>
> > +#include <linux/slab.h>
> > +#include <kunit/string-stream.h>
> > +
> > +int string_stream_vadd(struct string_stream *this,
> > +                    const char *fmt,
> > +                    va_list args)
> > +{
> > +     struct string_stream_fragment *fragment;
>
> Since there is field with the same name, please use a different
> name. Using the same name for the struct which contains a field
> of the same name get very confusing and will hard to maintain
> the code.
>
> > +     int len;
> > +     va_list args_for_counting;
> > +     unsigned long flags;
> > +
> > +     /* Make a copy because `vsnprintf` could change it */
> > +     va_copy(args_for_counting, args);
> > +
> > +     /* Need space for null byte. */
> > +     len = vsnprintf(NULL, 0, fmt, args_for_counting) + 1;
> > +
> > +     va_end(args_for_counting);
> > +
> > +     fragment = kmalloc(sizeof(*fragment), GFP_KERNEL);
> > +     if (!fragment)
> > +             return -ENOMEM;
> > +
> > +     fragment->fragment = kmalloc(len, GFP_KERNEL);
>
> This is confusing. See above comment.

Good point. Will fix in the next revision.

< snip >

Thanks!