/* $RCSfile: dcache.c,v $
-- $Revision: 1.8.2.1 $
-- last change: $Author: vq $ $Date: 2007/09/22 23:05:37 $
--
-- SYNOPSIS
-- Directory cache management routines.
--
-- DESCRIPTION
-- This is the code that maintains a directory cache for each directory
-- that dmake visits. The entire directory is thus only read once and
-- the need for performing costly 'stat' calls when performing target
-- inference is much reduced. The improvement in performance should be
-- significant for NFS or remote mounted file systems.
--
-- AUTHOR
-- Dennis Vadura, dvadura@dmake.wticorp.com
--
-- WWW
-- http://dmake.wticorp.com/
--
-- COPYRIGHT
-- Copyright (c) 1996,1997 by WTI Corp. All rights reserved.
--
-- This program is NOT free software; you can redistribute it and/or
-- modify it under the terms of the Software License Agreement Provided
-- in the file <distribution-root>/readme/license.txt.
--
-- LOG
-- Use cvs log to obtain detailed change logs.
*/
/* For Borland 5.00 compile, for some reason they seem to insist on pulling
* in the winnt.h if __WIN32__ is defined and you include <dirent.h>. This
* is, in my opinion, a BUG! on Borland's part.
*/
#if defined(__BORLANDC__) && defined(__WIN32__)
#undef __WIN32__
#endif
#ifdef __APPLE__
#include <sys/types.h>
#endif
#include <dirent.h>
#include "extern.h"
#include "sysintf.h"
typedef struct ent {
char *name;
uint32 hkey;
time_t mtime;
int isdir;
struct ent *next;
} Entry, *EntryPtr;
typedef struct mydir {
char *path;
uint32 hkey;
EntryPtr entries;
struct mydir *next;
} DirEntry, *DirEntryPtr;
static DirEntryPtr dtab[HASH_TABLE_SIZE];
/* Stat a path using the directory cache.
*
* We build a cannonical representation of the path using either an absolute
* path name if that is what 'path' is or the relative path name constructed
* from 'path' and the present value of Pwd.
*
* The present value of Pwd then gives a directory path that we search for
* in our cache using a hash lookup. If the directory component is located
* then we search the basename component of the path and return the result of
* the search: 0L if the component is not in the cache and it's time stamp
* otherwise.
*
* If the directory is not in our cache we insert it into the cache by
* openning the directory and reading all of the files within. Once read
* then we return the result of the above search.
*
* Optionally, if force is TRUE, and we did NOT read the directory to provide
* the result then stat the file anyway and update the internal cache.
*/
PUBLIC time_t
CacheStat(path, force)
char *path;
int force;
{
struct stat stbuf;
DirEntryPtr dp;
EntryPtr ep;
uint32 hkey;
uint16 hv;
char *fpath;
char *spath;
char *comp;
char *dir;
char *udir; /* Hold the unchanged (DcacheRespCase) directory. */
int loaded=FALSE;
if (If_root_path(path))
spath = path;
else
spath = Build_path(Pwd,path);
fpath = DmStrDup(spath);
comp = Basename(fpath); /* Use before the Filedir() call. */
dir = Filedir(fpath);
/* do caching and comparing lower case if told so. */
if( !STOBOOL(DcacheRespCase) ) {
udir = DmStrDup(dir);
strlwr(comp);
strlwr(dir);
} else
udir = dir;
hv = Hash(dir,&hkey);
for(dp=dtab[hv]; dp; dp=dp->next)
if (hkey == dp->hkey && strcmp(dp->path,dir) == 0)
break;
if (!dp) {
/* Not cached yet, doing it now. */
DIR *dirp;
struct dirent *direntp;
if( Verbose & V_DIR_CACHE )
printf( "%s: Caching directory [%s]\n", Pname, dir );
/* Load the directory, we have the right hash position already */
loaded = TRUE;
TALLOC(dp,1,DirEntry);
dp->next = dtab[hv];
dtab[hv] = dp;
dp->path = DmStrDup(dir);
dp->hkey = hkey;
/* We use the unchanged (not potentially lowercased because of
* DcacheRespCase) directory as this would fail on a case sensitive
* file system.
* Note: Using case insensitive directory caching on case sensitive
* file systems is a *BAD* idea. If in doubt use case sensitive
* directory caching even on case insensitive file systems as the
* worst case in this szenario is that /foo/bar/ and /foo/BAR/ are
* cached separately (with the same content) even though they are
* the same directory. This would only happen if different targets
* using different upper/lower case spellings for the same directory
* and is *never* a good idea. */
if (Set_dir(udir) == 0) {
if((dirp=opendir(".")) != NIL(DIR)) {
while((direntp=readdir(dirp)) != NULL) {
TALLOC(ep,1,Entry);
ep->name = DmStrDup(direntp->d_name); /* basename only */
if( !STOBOOL(DcacheRespCase) )
strlwr(ep->name);
Hash(ep->name, &ep->hkey); /* This sets ep->hkey. */
ep->next = dp->entries;
dp->entries = ep;
DMSTAT(direntp->d_name,&stbuf);
ep->isdir = (stbuf.st_mode & S_IFDIR);
ep->mtime = stbuf.st_mtime;
}
closedir(dirp);
}
Set_dir(Pwd);
}
}
Hash(comp, &hkey); /* Calculate hkey. */
/* search in dp->entries for comp. */
if (dp) {
for(ep=dp->entries; ep; ep=ep->next)
if(hkey == ep->hkey && strcmp(ep->name,comp) == 0)
break;
}
else
ep = NULL;
if( force && !loaded) {
if (strlen(comp) > NameMax || DMSTAT(spath,&stbuf) != 0) {
/* Either file to long or the stat failed. */
if (strlen(comp) > NameMax)
Warning( "File [%s] longer than value of NAMEMAX [%d].\n\
Assume unix time 0.\n", comp, NameMax );
if(ep)
ep->mtime = 0L;
}
else {
if (!ep) {
TALLOC(ep,1,Entry);
ep->name = DmStrDup(comp);
if( !STOBOOL(DcacheRespCase) )
strlwr(ep->name);
Hash(ep->name, &ep->hkey);
ep->next = dp->entries;
ep->isdir = (stbuf.st_mode & S_IFDIR);
dp->entries = ep;
}
ep->mtime = stbuf.st_mtime;
}
if( Verbose & V_DIR_CACHE )
printf("%s: Updating dir cache entry for [%s], new time is %ld\n",
Pname, spath, ep ? ep->mtime : 0L);
}
if( udir != dir )
FREE(udir); /* Keep this before the free of fpath. */
FREE(fpath);
return(!ep ? (time_t)0L : ((STOBOOL(Augmake) && ep->isdir)?0L:ep->mtime));
}
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