-/*** cache.c -- Allows you to have more bfds open than your system has fds. */
+/* BFD library -- caching of file descriptors.
+ Copyright 1990, 1991, 1992, 1994 Free Software Foundation, Inc.
-/* Copyright (C) 1990, 1991 Free Software Foundation, Inc.
+This file is part of BFD, the Binary File Descriptor library.
-This file is part of BFD, the Binary File Diddler.
-
-BFD is free software; you can redistribute it and/or modify
+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
-the Free Software Foundation; either version 1, or (at your option)
-any later version.
+the Free Software Foundation; either version 2 of the License, or
+(at your option) any later version.
-BFD is distributed in the hope that it will be useful,
+This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
-along with BFD; see the file COPYING. If not, write to
-the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+/*
+SECTION
+ File caching
+
+ The file caching mechanism is embedded within BFD and allows
+ the application to open as many BFDs as it wants without
+ regard to the underlying operating system's file descriptor
+ 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
+ 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.
+
+*/
-/* $Id$ */
-#include "sysdep.h"
#include "bfd.h"
+#include "sysdep.h"
#include "libbfd.h"
-/* These declarations should not be needed; libbfd.h's inclusion should
- have handled it.
- int fclose();
- int fseek();
-*/
+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
+DESCRIPTION
+ The maximum number of files which the cache will keep open at
+ one time.
+
+.#define BFD_CACHE_MAX_OPEN 10
+
+*/
-/* The maximum number of FDs opened by bfd */
-#define BFD_CACHE_MAX_OPEN 10
+/* The number of BFD files we have open. */
-/* when this exceeds BFD_CACHE_MAX_OPEN, we get to work */
static int open_files;
-static bfd *cache_sentinel; /* Chain of bfds with active fds we've
- opened */
-static void
-bfd_cache_delete();
+/*
+INTERNAL_FUNCTION
+ bfd_last_cache
+
+SYNOPSIS
+ extern bfd *bfd_last_cache;
+
+DESCRIPTION
+ Zero, or a pointer to the topmost BFD on the chain. This is
+ used by the <<bfd_cache_lookup>> macro in @file{libbfd.h} to
+ determine when it can avoid a function call.
+*/
bfd *bfd_last_cache;
-\f
-static void
-close_one()
+/*
+ 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))
+
+
+ */
+
+/* Insert a BFD into the cache. */
+
+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;
+ }
+ 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;
+}
- kill->where = ftell((FILE *)(kill->iostream));
- bfd_cache_delete(kill);
+/* Remove a BFD from the cache. */
-}
-/* Cuts the bfd abfd out of the chain in the cache */
-static void
+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;
+ }
}
-static void
+/* We need to open a new file, and the cache is full. Find the least
+ recently used cacheable BFD and close it. */
+
+static boolean
+close_one ()
+{
+ register bfd *kill;
+
+ 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;
{
- fclose ((FILE *)(abfd->iostream));
+ 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--;
-}
-
-static bfd *
-insert(x,y)
-bfd *x;
-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
+ --open_files;
-/* Initialize a BFD by putting it on the cache LRU. */
-void
-bfd_cache_init(abfd)
-bfd *abfd;
-{
- cache_sentinel = insert(abfd, cache_sentinel);
+ return ret;
}
-void
-bfd_cache_close(abfd)
-bfd *abfd;
+/*
+INTERNAL_FUNCTION
+ bfd_cache_init
+
+SYNOPSIS
+ boolean bfd_cache_init (bfd *abfd);
+
+DESCRIPTION
+ Add a newly opened BFD to the cache.
+*/
+
+boolean
+bfd_cache_init (abfd)
+ bfd *abfd;
{
- /* If this file is open then remove from the chain */
- if (abfd->iostream)
+ BFD_ASSERT (abfd->iostream != NULL);
+ if (open_files >= BFD_CACHE_MAX_OPEN)
{
- bfd_cache_delete(abfd);
+ if (! close_one ())
+ return false;
}
+ insert (abfd);
+ ++open_files;
+ return true;
}
-\f
-/* 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. */
+
+/*
+INTERNAL_FUNCTION
+ bfd_cache_close
+
+SYNOPSIS
+ boolean bfd_cache_close (bfd *abfd);
+
+DESCRIPTION
+ Remove the BFD @var{abfd} from the cache. If the attached file is open,
+ then close it too.
+
+RETURNS
+ <<false>> is returned if closing the file fails, <<true>> is
+ returned if all is well.
+*/
+
+boolean
+bfd_cache_close (abfd)
+ bfd *abfd;
+{
+ 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 @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.
+*/
FILE *
bfd_open_file (abfd)
bfd *abfd;
{
- abfd->cacheable = true; /* Allow it to be closed later. */
- if(open_files >= BFD_CACHE_MAX_OPEN) {
- close_one();
+ abfd->cacheable = true; /* Allow it to be closed later. */
+
+ if (open_files >= BFD_CACHE_MAX_OPEN)
+ {
+ if (! close_one ())
+ return NULL;
}
- switch (abfd->direction) {
- case read_direction:
- case no_direction:
- abfd->iostream = (char *) fopen(abfd->filename, "r");
- break;
- case both_direction:
- case write_direction:
- if (abfd->opened_once == true) {
- abfd->iostream = (char *) fopen(abfd->filename, "r+");
- if (!abfd->iostream) {
- abfd->iostream = (char *) fopen(abfd->filename, "w+");
- }
- } else {
- /*open for creat */
- abfd->iostream = (char *) fopen(abfd->filename, "w");
- abfd->opened_once = true;
+
+ 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);
}
- break;
+ else
+ {
+ /*open for creat */
+ abfd->iostream = (PTR) fopen (abfd->filename, FOPEN_WB);
+ abfd->opened_once = true;
+ }
+ break;
}
- if (abfd->iostream) {
- open_files++;
- bfd_cache_init (abfd);
+
+ if (abfd->iostream != NULL)
+ {
+ if (! bfd_cache_init (abfd))
+ return NULL;
}
- return (FILE *)(abfd->iostream);
+ return (FILE *) abfd->iostream;
}
-/* Find a file descriptor for this BFD. If necessary, open it.
- If there are already more than BFD_CACHE_MAX_OPEN files open, try to close
- one first, to avoid running out of file descriptors. */
+/*
+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. 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.
+*/
FILE *
bfd_cache_lookup_worker (abfd)
bfd *abfd;
{
+ if ((abfd->flags & BFD_IN_MEMORY) != 0)
+ abort ();
+
if (abfd->my_archive)
+ abfd = abfd->my_archive;
+
+ if (abfd->iostream != NULL)
{
- 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 */
- snip (abfd);
- cache_sentinel = insert(abfd, cache_sentinel);
- }
+ /* Move the file to the start of the cache. */
+ if (abfd != bfd_last_cache)
+ {
+ snip (abfd);
+ 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
+ else
{
-
- if (open_files >= BFD_CACHE_MAX_OPEN)
- {
- close_one();
+ 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;
}
projects / binutils.git / blobdiff