Re: Debugging case refs

[John Darrington]

Looks ok to me.  I've not tried it.
Let's check it in and see.....

On Tue, Oct 26, 2010 at 07:35:53AM -0700, Ben Pfaff wrote:
     John Darrington <address@hidden> writes:
     
     > On Mon, Oct 25, 2010 at 09:57:47PM -0700, Ben Pfaff wrote:
     >      
     >      From: Ben Pfaff <address@hidden>
     >      Date: Mon, 25 Oct 2010 21:56:48 -0700
     >      Subject: [PATCH] case: Add support for debugging case reference 
count leaks.
     >       
     >      -static inline struct ccase *case_ref (const struct ccase *);
     >      +struct ccase *case_ref (const struct ccase *);
     >
     > I think it's important that the case_ref function has the 
WARN_UNUSED_RESULT flag.
     > When DEBUG_CASEREFS=1, simply calling case_ref (c) without assigning the 
result
     > will not copy the case.
     
     Good point, thanks.
     
     Here's the same patch with that one change:
     
     --8<--------------------------cut here-------------------------->8--
     
     From: Ben Pfaff <address@hidden>
     Date: Tue, 26 Oct 2010 07:34:45 -0700
     Subject: [PATCH] case: Add support for debugging case reference count 
leaks.
     
     ---
      src/data/case.c |   23 ++++++++++++++++++++++-
      src/data/case.h |   14 ++------------
      2 files changed, 24 insertions(+), 13 deletions(-)
     
     diff --git a/src/data/case.c b/src/data/case.c
     index dc40292..ffb47fe 100644
     --- a/src/data/case.c
     +++ b/src/data/case.c
     @@ -1,5 +1,5 @@
      /* PSPP - a program for statistical analysis.
     -   Copyright (C) 2004, 2007, 2009 Free Software Foundation, Inc.
     +   Copyright (C) 2004, 2007, 2009, 2010 Free Software Foundation, Inc.
      
         This program is free software: you can redistribute it and/or modify
         it under the terms of the GNU General Public License as published by
     @@ -30,6 +30,14 @@
      #include "minmax.h"
      #include "xalloc.h"
      
     +/* Set this flag to 1 to copy cases instead of ref counting them.
     +   This is sometimes helpful in debugging situations. */
     +#define DEBUG_CASEREFS 0
     +
     +#if DEBUG_CASEREFS
     +#warning "Caseref debug enabled.  CASES ARE NOT BEING SHARED!!"
     +#endif
     +
      static size_t case_size (const struct caseproto *);
      static bool variable_matches_case (const struct ccase *,
                                         const struct variable *);
     @@ -80,6 +88,19 @@ case_clone (const struct ccase *c)
        return case_unshare (case_ref (c));
      }
      
     +/* Increments case C's reference count and returns C.  Afterward,
     +   case C is shared among its reference count holders. */
     +struct ccase *
     +case_ref (const struct ccase *c_)
     +{
     +  struct ccase *c = CONST_CAST (struct ccase *, c_);
     +  c->ref_cnt++;
     +#if DEBUG_CASEREFS
     +  c = case_unshare__ (c);
     +#endif
     +  return c;
     +}
     +
      /* Returns an estimate of the number of bytes of memory that
         would be consumed in creating a case based on PROTO.  The
         estimate includes typical overhead from malloc() in addition
     diff --git a/src/data/case.h b/src/data/case.h
     index d00c2ad..c07b07d 100644
     --- a/src/data/case.h
     +++ b/src/data/case.h
     @@ -1,5 +1,5 @@
      /* PSPP - a program for statistical analysis.
     -   Copyright (C) 2004, 2007, 2009 Free Software Foundation, Inc.
     +   Copyright (C) 2004, 2007, 2009, 2010 Free Software Foundation, Inc.
      
         This program is free software: you can redistribute it and/or modify
         it under the terms of the GNU General Public License as published by
     @@ -61,7 +61,7 @@ struct ccase *case_try_create (const struct caseproto *) 
MALLOC_LIKE;
      struct ccase *case_clone (const struct ccase *) MALLOC_LIKE;
      
      static inline struct ccase *case_unshare (struct ccase *) 
WARN_UNUSED_RESULT;
     -static inline struct ccase *case_ref (const struct ccase *);
     +struct ccase *case_ref (const struct ccase *) WARN_UNUSED_RESULT;
      static inline void case_unref (struct ccase *);
      static inline bool case_is_shared (const struct ccase *);
      
     @@ -130,16 +130,6 @@ case_unshare (struct ccase *c)
        return c;
      }
      
     -/* Increments case C's reference count and returns C.  Afterward,
     -   case C is shared among its reference count holders. */
     -static inline struct ccase *
     -case_ref (const struct ccase *c_)
     -{
     -  struct ccase *c = CONST_CAST (struct ccase *, c_);
     -  c->ref_cnt++;
     -  return c;
     -}
     -
      /* Decrements case C's reference count.  Frees C if its
         reference count drops to 0.
      
     -- 
     Ben Pfaff 
     http://benpfaff.org

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