[sheepdog] [PATCH v2 1/4] util: solve cyclic dependency of util.h and logger.h

[Hitoshi Mitake]

At Tue, 9 Jul 2013 16:51:04 +0800,
Liu Yuan wrote:
> 
> On Tue, Jul 09, 2013 at 04:42:00PM +0900, Hitoshi Mitake wrote:
> > Current sheepdog specialized assert() in util.h cannot be used by
> > util.h itself because it depends on logger.h and logger.h depends on
> > util.h, too.
> > 
> > This patch solves this cyclic dependency.
> > 
> > Signed-off-by: Hitoshi Mitake <mitake.hitoshi at lab.ntt.co.jp>
> > ---
> > 
> > v2:
> >  - stop let treeview.c and shadow_file.c include logger.h
> > 
> >  include/logger.h |    6 ++++++
> >  include/util.h   |   39 ++++++++++++++++++++++++---------------
> >  2 files changed, 30 insertions(+), 15 deletions(-)
> > 
> > diff --git a/include/logger.h b/include/logger.h
> > index 5c9aab6..41a1488 100644
> > --- a/include/logger.h
> > +++ b/include/logger.h
> > @@ -81,4 +81,10 @@ void sd_backtrace(void);
> >  		log_write(SDOG_DEBUG, __func__, __LINE__, fmt, ##args);	\
> >  	} while (0)
> >  
> > +static inline void do_assert(const char *expr, const char *func, int line)
> > +{
> > +	log_write(SDOG_EMERG, func, line, "Asserting `%s' failed.", expr);
> > +	abort();
> > +}
> > +
> >  #endif	/* LOG_H */
> > diff --git a/include/util.h b/include/util.h
> > index e70bb9f..1517680 100644
> > --- a/include/util.h
> > +++ b/include/util.h
> > @@ -14,6 +14,23 @@
> >  #include "bitops.h"
> >  #include "list.h"
> >  
> > +static inline void do_assert(const char *expr, const char *func, int line);
> > +
> > +#ifdef assert
> > +#undef assert
> > +#endif
> > +
> > +#ifndef NDEBUG
> > +
> > +#define assert(expr) ((expr) ?				\
> > +			(void)0 : do_assert(#expr, __func__, __LINE__))
> > +
> > +#else
> > +
> > +#define assert(expr) ((void)0)
> > +
> > +#endif	/* NDEBUG */
> > +
> >  #define SECTOR_SIZE (1U << 9)
> >  #define BLOCK_SIZE (1U << 12)
> >  
> > @@ -161,21 +178,6 @@ int atomic_create_and_write(const char *path, char *buf, size_t len);
> >  	__removed;							\
> >  })
> >  
> > -#ifdef assert
> > -#undef assert
> > -#endif
> > -
> > -#ifndef NDEBUG
> > -
> > -#define assert(expr) ((expr) ?						\
> > -			(void)0 : panic("Asserting `%s' failed.", #expr))
> > -
> > -#else
> > -
> > -#define assert(expr) ((void)0)
> > -
> > -#endif	/* NDEBUG */
> > -
> >  /* urcu helpers */
> >  
> >  /* Boolean data type which can be accessed by multiple threads */
> > @@ -243,4 +245,11 @@ extern mode_t sd_def_dmode;
> >  /* Force a compilation error if the condition is true */
> >  #define BUILD_BUG_ON(condition) ((void)sizeof(struct { int: -!!(condition); }))
> >  
> > +/*
> > + * The below including of logger.h is required for suppressing compiler warning
> > + * because if .c file include util.h but not logger.h, the prototype
> > + * declaration of do_assert() is treated as defined but not used function.
> > + */
> > +#include "logger.h"
> > +
> >  #endif
> 
> This looks too hacky to me, can we find a better method?

I tried to seek other methods (e.g. using gcc extensions) but
concluded this solution is an only way to solve the problem.

I think this one is not so hacky because almost every .c file includes
both of util.h and logger.h. treeview.c and shadow_files.c are only
exceptions.

Thanks,
Hitoshi