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Diffstat (limited to 'dmake/unix/dcache.c')
| -rw-r--r-- | dmake/unix/dcache.c | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/dmake/unix/dcache.c b/dmake/unix/dcache.c new file mode 100644 index 000000000000..e0ebf59da553 --- /dev/null +++ b/dmake/unix/dcache.c @@ -0,0 +1,223 @@ +/* $RCSfile: dcache.c,v $ +-- $Revision: 1.9 $ +-- last change: $Author: ihi $ $Date: 2007-10-15 15:52:47 $ +-- +-- 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)); +} |