/* BFD library -- caching of file descriptors.
- Copyright 1990, 1991, 1992 Free Software Foundation, Inc.
+ Copyright 1990, 1991, 1992, 1994 Free Software Foundation, Inc.
This file is part of BFD, the Binary File Descriptor library.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
-Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
/*
SECTION
- File Caching
+ File caching
The file caching mechanism is embedded within BFD and allows
the application to open as many BFDs as it wants without
limit (often as low as 20 open files). The module in
<<cache.c>> maintains a least recently used list of
<<BFD_CACHE_MAX_OPEN>> files, and exports the name
- <<bfd_cache_lookup>> which runs around and makes sure that
+ <<bfd_cache_lookup>>, which runs around and makes sure that
the required BFD is open. If not, then it chooses a file to
close, closes it and opens the one wanted, returning its file
handle.
#include "sysdep.h"
#include "libbfd.h"
+static void insert PARAMS ((bfd *));
+static void snip PARAMS ((bfd *));
+static boolean close_one PARAMS ((void));
+static boolean bfd_cache_delete PARAMS ((bfd *));
+
/*
INTERNAL_FUNCTION
BFD_CACHE_MAX_OPEN macro
*/
+/* The number of BFD files we have open. */
static int open_files;
-static bfd *cache_sentinel; /* Chain of BFDs with active fds we've
- opened */
-
/*
INTERNAL_FUNCTION
bfd_last_cache
bfd *bfd_last_cache;
/*
- * INTERNAL_FUNCTION
- * bfd_cache_lookup
- *
- * DESCRIPTION
- * Checks to see if the required BFD is the same as the last one
- * looked up. If so then it can use the iostream in the BFD with
- * impunity, since it can't have changed since the last lookup,
- * otherwise it has to perform the complicated lookup function
- *
- * .#define bfd_cache_lookup(x) \
- * . ((x)==bfd_last_cache? \
- * . (FILE*)(bfd_last_cache->iostream): \
- * . bfd_cache_lookup_worker(x))
- *
- *
+ INTERNAL_FUNCTION
+ bfd_cache_lookup
+
+ DESCRIPTION
+ Check to see if the required BFD is the same as the last one
+ looked up. If so, then it can use the stream in the BFD with
+ impunity, since it can't have changed since the last lookup;
+ otherwise, it has to perform the complicated lookup function.
+
+ .#define bfd_cache_lookup(x) \
+ . ((x)==bfd_last_cache? \
+ . (FILE*)(bfd_last_cache->iostream): \
+ . bfd_cache_lookup_worker(x))
+
+
*/
-static boolean EXFUN(bfd_cache_delete,(bfd *));
-
+/* Insert a BFD into the cache. */
-static void
-DEFUN_VOID(close_one)
+static INLINE void
+insert (abfd)
+ bfd *abfd;
{
- bfd *kill = cache_sentinel;
- if (kill == 0) /* Nothing in the cache */
- return ;
-
- /* We can only close files that want to play this game. */
- while (!kill->cacheable) {
- kill = kill->lru_prev;
- if (kill == cache_sentinel) /* Nobody wants to play */
- return ;
+ if (bfd_last_cache == NULL)
+ {
+ abfd->lru_next = abfd;
+ abfd->lru_prev = abfd;
}
-
- kill->where = ftell((FILE *)(kill->iostream));
- (void) bfd_cache_delete(kill);
+ else
+ {
+ abfd->lru_next = bfd_last_cache;
+ abfd->lru_prev = bfd_last_cache->lru_prev;
+ abfd->lru_prev->lru_next = abfd;
+ abfd->lru_next->lru_prev = abfd;
+ }
+ bfd_last_cache = abfd;
}
-/* Cuts the BFD abfd out of the chain in the cache */
-static void
-DEFUN(snip,(abfd),
- bfd *abfd)
+/* Remove a BFD from the cache. */
+
+static INLINE void
+snip (abfd)
+ bfd *abfd;
{
abfd->lru_prev->lru_next = abfd->lru_next;
- abfd->lru_next->lru_prev = abfd->lru_prev;
- if (cache_sentinel == abfd) cache_sentinel = (bfd *)NULL;
+ abfd->lru_next->lru_prev = abfd->lru_prev;
+ if (abfd == bfd_last_cache)
+ {
+ bfd_last_cache = abfd->lru_next;
+ if (abfd == bfd_last_cache)
+ bfd_last_cache = NULL;
+ }
}
+/* We need to open a new file, and the cache is full. Find the least
+ recently used cacheable BFD and close it. */
+
static boolean
-DEFUN(bfd_cache_delete,(abfd),
- bfd *abfd)
+close_one ()
{
- boolean ret;
+ register bfd *kill;
- if (fclose ((FILE *)(abfd->iostream)) == EOF)
- ret = false;
+ if (bfd_last_cache == NULL)
+ kill = NULL;
else
+ {
+ for (kill = bfd_last_cache->lru_prev;
+ ! kill->cacheable;
+ kill = kill->lru_prev)
+ {
+ if (kill == bfd_last_cache)
+ {
+ kill = NULL;
+ break;
+ }
+ }
+ }
+
+ if (kill == NULL)
+ {
+ /* There are no open cacheable BFD's. */
+ return true;
+ }
+
+ kill->where = ftell ((FILE *) kill->iostream);
+
+ return bfd_cache_delete (kill);
+}
+
+/* Close a BFD and remove it from the cache. */
+
+static boolean
+bfd_cache_delete (abfd)
+ bfd *abfd;
+{
+ boolean ret;
+
+ if (fclose ((FILE *) abfd->iostream) == 0)
ret = true;
+ else
+ {
+ ret = false;
+ bfd_set_error (bfd_error_system_call);
+ }
+
snip (abfd);
+
abfd->iostream = NULL;
- open_files--;
- bfd_last_cache = 0;
+ --open_files;
+
return ret;
}
-
-static bfd *
-DEFUN(insert,(x,y),
- bfd *x AND
- bfd *y)
-{
- if (y) {
- x->lru_next = y;
- x->lru_prev = y->lru_prev;
- y->lru_prev->lru_next = x;
- y->lru_prev = x;
-
- }
- else {
- x->lru_prev = x;
- x->lru_next = x;
- }
- return x;
-}
-\f
/*
INTERNAL_FUNCTION
bfd_cache_init
SYNOPSIS
- void bfd_cache_init (bfd *);
+ boolean bfd_cache_init (bfd *abfd);
DESCRIPTION
- Initialize a BFD by putting it on the cache LRU.
+ Add a newly opened BFD to the cache.
*/
-void
-DEFUN(bfd_cache_init,(abfd),
- bfd *abfd)
+boolean
+bfd_cache_init (abfd)
+ bfd *abfd;
{
- cache_sentinel = insert(abfd, cache_sentinel);
+ BFD_ASSERT (abfd->iostream != NULL);
+ if (open_files >= BFD_CACHE_MAX_OPEN)
+ {
+ if (! close_one ())
+ return false;
+ }
+ insert (abfd);
+ ++open_files;
+ return true;
}
-
/*
INTERNAL_FUNCTION
bfd_cache_close
+SYNOPSIS
+ boolean bfd_cache_close (bfd *abfd);
+
DESCRIPTION
- Remove the BFD from the cache. If the attached file is open,
+ Remove the BFD @var{abfd} from the cache. If the attached file is open,
then close it too.
-SYNOPSIS
- boolean bfd_cache_close (bfd *);
-
RETURNS
<<false>> is returned if closing the file fails, <<true>> is
returned if all is well.
*/
+
boolean
-DEFUN(bfd_cache_close,(abfd),
- bfd *abfd)
+bfd_cache_close (abfd)
+ bfd *abfd;
{
- /* If this file is open then remove from the chain */
- if (abfd->iostream)
- {
- return bfd_cache_delete(abfd);
- }
- else
- {
- return true;
- }
+ if (abfd->iostream == NULL
+ || (abfd->flags & BFD_IN_MEMORY) != 0)
+ return true;
+
+ return bfd_cache_delete (abfd);
}
/*
INTERNAL_FUNCTION
bfd_open_file
+SYNOPSIS
+ FILE* bfd_open_file(bfd *abfd);
+
DESCRIPTION
- Call the OS to open a file for this BFD. Returns the FILE *
- (possibly null) that results from this operation. Sets up the
- BFD so that future accesses know the file is open. If the FILE
- * returned is null, then there is won't have been put in the
+ Call the OS to open a file for @var{abfd}. Return the <<FILE *>>
+ (possibly <<NULL>>) that results from this operation. Set up the
+ BFD so that future accesses know the file is open. If the <<FILE *>>
+ returned is <<NULL>>, then it won't have been put in the
cache, so it won't have to be removed from it.
-
-SYNOPSIS
- FILE* bfd_open_file(bfd *);
*/
FILE *
-DEFUN(bfd_open_file, (abfd),
- bfd *abfd)
+bfd_open_file (abfd)
+ bfd *abfd;
{
abfd->cacheable = true; /* Allow it to be closed later. */
- if(open_files >= BFD_CACHE_MAX_OPEN) {
- close_one();
- }
-
- switch (abfd->direction) {
- case read_direction:
- case no_direction:
- abfd->iostream = (char *) fopen(abfd->filename, FOPEN_RB);
- break;
- case both_direction:
- case write_direction:
- if (abfd->opened_once == true) {
- abfd->iostream = (char *) fopen(abfd->filename, FOPEN_RUB);
- if (!abfd->iostream) {
- abfd->iostream = (char *) fopen(abfd->filename, FOPEN_WUB);
- }
- } else {
- /*open for creat */
- abfd->iostream = (char *) fopen(abfd->filename, FOPEN_WB);
- abfd->opened_once = true;
+ if (open_files >= BFD_CACHE_MAX_OPEN)
+ {
+ if (! close_one ())
+ return NULL;
}
- break;
- }
- if (abfd->iostream) {
- open_files++;
- bfd_cache_init (abfd);
- }
+ switch (abfd->direction)
+ {
+ case read_direction:
+ case no_direction:
+ abfd->iostream = (PTR) fopen (abfd->filename, FOPEN_RB);
+ break;
+ case both_direction:
+ case write_direction:
+ if (abfd->opened_once == true)
+ {
+ abfd->iostream = (PTR) fopen (abfd->filename, FOPEN_RUB);
+ if (abfd->iostream == NULL)
+ abfd->iostream = (PTR) fopen (abfd->filename, FOPEN_WUB);
+ }
+ else
+ {
+ /*open for creat */
+ abfd->iostream = (PTR) fopen (abfd->filename, FOPEN_WB);
+ abfd->opened_once = true;
+ }
+ break;
+ }
+
+ if (abfd->iostream != NULL)
+ {
+ if (! bfd_cache_init (abfd))
+ return NULL;
+ }
- return (FILE *)(abfd->iostream);
+ return (FILE *) abfd->iostream;
}
/*
INTERNAL_FUNCTION
bfd_cache_lookup_worker
+SYNOPSIS
+ FILE *bfd_cache_lookup_worker(bfd *abfd);
+
DESCRIPTION
Called when the macro <<bfd_cache_lookup>> fails to find a
- quick answer. Finds a file descriptor for this BFD. If
- necessary, it open it. If there are already more than
- BFD_CACHE_MAX_OPEN files open, it trys to close one first, to
+ quick answer. Find a file descriptor for @var{abfd}. If
+ necessary, it open it. If there are already more than
+ <<BFD_CACHE_MAX_OPEN>> files open, it tries to close one first, to
avoid running out of file descriptors.
-
-SYNOPSIS
- FILE *bfd_cache_lookup_worker(bfd *);
-
*/
FILE *
-DEFUN(bfd_cache_lookup_worker,(abfd),
- bfd *abfd)
+bfd_cache_lookup_worker (abfd)
+ bfd *abfd;
{
+ if ((abfd->flags & BFD_IN_MEMORY) != 0)
+ abort ();
+
if (abfd->my_archive)
- {
- abfd = abfd->my_archive;
- }
- /* Is this file already open .. if so then quick exit */
- if (abfd->iostream)
- {
- if (abfd != cache_sentinel) {
- /* Place onto head of lru chain */
+ abfd = abfd->my_archive;
+
+ if (abfd->iostream != NULL)
+ {
+ /* Move the file to the start of the cache. */
+ if (abfd != bfd_last_cache)
+ {
snip (abfd);
- cache_sentinel = insert(abfd, cache_sentinel);
+ insert (abfd);
}
- }
- /* This is a BFD without a stream -
- so it must have been closed or never opened.
- find an empty cache entry and use it. */
- else
- {
-
- if (open_files >= BFD_CACHE_MAX_OPEN)
- {
- close_one();
- }
+ }
+ else
+ {
+ if (bfd_open_file (abfd) == NULL)
+ return NULL;
+ if (fseek ((FILE *) abfd->iostream, abfd->where, SEEK_SET) != 0)
+ return NULL;
+ }
- BFD_ASSERT(bfd_open_file (abfd) != (FILE *)NULL) ;
- fseek((FILE *)(abfd->iostream), abfd->where, false);
- }
- bfd_last_cache = abfd;
- return (FILE *)(abfd->iostream);
+ return (FILE *) abfd->iostream;
}
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