X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=chiark-tcl.git;a=blobdiff_plain;f=cdb%2Fwriteable.c;h=02c98cb8ad773230984f454f02f8b3205d826213;hp=9f692d5dfd4df396b193260af763d86b5571bf03;hb=29fc9adb0f9c6ade500203bfda4359cba1d59ff7;hpb=ebd7e30dd682685e1f4390718ec2797b8e902768

diff --git a/cdb/writeable.c b/cdb/writeable.c
index 9f692d5..02c98cb 100644
--- a/cdb/writeable.c
+++ b/cdb/writeable.c
@@ -1,7 +1,27 @@
-/**/
+/*
+ * cdb, cdb-wr - Tcl bindings for tinycdb and a journalling write extension
+ * Copyright 2006 Ian Jackson
+ *
+ * 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 2 of the
+ * License, or (at your option) any later version.
+ *
+ * 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
 
 #include "chiark_tcl_cdb.h"
 
+#define KEYLEN_MAX (INT_MAX/2)
+
 #define ftello ftell
 #define fseeko fseek
 
@@ -15,9 +35,7 @@ static void maybe_close(int fd) {
   if (fd>=0) close(fd);
 }
 
-#define PE(m) do{						\
-    rc= cht_posixerr(ip, errno, "failed to " m); goto x_rc;	\
-  }while(0)
+/*==================== Subsystems and subtypes ====================*/
 
 /*---------- Pathbuf ----------*/
 
@@ -25,14 +43,14 @@ typedef struct Pathbuf {
   char *buf, *sfx;
 } Pathbuf;
 
-#define MAX_SUFFIX 4
+#define MAX_SUFFIX 5
 
 static void pathbuf_init(Pathbuf *pb, const char *pathb) {
-  int l= strlen(pathb);
-  pb->buf= TALLOC(l + 4);
+  size_t l= strlen(pathb);
+  assert(l < INT_MAX);
+  pb->buf= TALLOC(l + MAX_SUFFIX + 1);
   memcpy(pb->buf, pathb, l);
   pb->sfx= pb->buf + l;
-  *pb->sfx++= '.';
 }
 static const char *pathbuf_sfx(Pathbuf *pb, const char *suffix) {
   assert(strlen(suffix) <= MAX_SUFFIX);
@@ -61,13 +79,11 @@ static HashValue *htv_prep(int len) {
   HashValue *hd;
   hd= TALLOC((hd->data - (Byte*)hd) + len);
   hd->len= len;
+  return hd;
 }  
 static Byte *htv_fillptr(HashValue *hd) {
   return hd->data;
 }
-static void htv_fill(HashValue *hd, const Byte *data) {
-  memcpy(hd->data, data, hd->len);
-}
 
 static void ht_setup(HashTable *ht) {
   Tcl_InitHashTable(&ht->t, TCL_STRING_KEYS);
@@ -92,11 +108,20 @@ static void ht_maybeupdate(HashTable *ht, const char *key,
   Tcl_SetHashValue(he, val_eat);
 }
 
+static const HashValue *ht_lookup(HashTable *ht, const char *key) {
+  Tcl_HashEntry *he;
+  
+  he= Tcl_FindHashEntry(&ht->t, key);
+  if (!he) return 0;
+  
+  return Tcl_GetHashValue(he);
+}
+
 static int ht_forall(HashTable *ht,
-		     int (*fn)(const char *key, const HashValue *val,
+		     int (*fn)(const char *key, HashValue *val,
 			       struct ht_forall_ctx *ctx),
 		     struct ht_forall_ctx *ctx) {
-  /* Returns first nonzero value returned by any call to fn, or 0. */
+  /* Returns first positive value returned by any call to fn, or 0. */
   Tcl_HashSearch sp;
   Tcl_HashEntry *he;
   const char *key;
@@ -124,23 +149,25 @@ static void ht_destroy(HashTable *ht) {
   for (he= Tcl_FirstHashEntry(&ht->t, &sp);
        he;
        he= Tcl_NextHashEntry(&sp)) {
+    /* ht_forall skips empty (deleted) entries so is no good for this */
     TFREE(Tcl_GetHashValue(he));
   }
   Tcl_DeleteHashTable(&ht->t);
 }
 
+/*==================== Existential ====================*/
+
 /*---------- Rw data structure ----------*/
 
-typedef struct {
-  int ix, autocompact, maxage;
-fixme implement maxage during compact;
+typedef struct Rw {
+  int ix, autocompact;
   int cdb_fd, lock_fd;
   struct cdb cdb; /* valid iff cdb_fd >= 0 */
-  off_t cdb_bytes; /* valid iff cdb_fd >= 0 */
-  FILE *logfile;
+  FILE *logfile; /* may be 0; if so, is broken */
   HashTable logincore;
   Pathbuf pbsome, pbother;
   off_t mainsz;
+  ScriptToInvoke on_info, on_lexminval;
 } Rw;
 
 static int rw_close(Tcl_Interp *ip, Rw *rw) {
@@ -148,21 +175,24 @@ static int rw_close(Tcl_Interp *ip, Rw *rw) {
 
   rc= TCL_OK;
   ht_destroy(&rw->logincore);
+  if (rw->cdb_fd >= 0) cdb_free(&rw->cdb);
   maybe_close(rw->cdb_fd);
   maybe_close(rw->lock_fd);
 
   if (rw->logfile) {
     r= fclose(rw->logfile);
-    if (r && ip) { rc= cht_posixerr(ip, errno, "data loss! failed to"
+    if (r && ip) { rc= cht_posixerr(ip, errno, "probable data loss! failed to"
 				    " fclose logfile during untidy close"); }
   }
 
   pathbuf_free(&rw->pbsome); pathbuf_free(&rw->pbother);
-  TFREE(rw);
   return rc;
 }
 
-static void destroy_cdbrw_idtabcb(Tcl_Interp *ip, void *rw) { rw_close(0,rw); }
+static void destroy_cdbrw_idtabcb(Tcl_Interp *ip, void *rw_v) {
+  rw_close(0,rw_v);
+  TFREE(rw_v);
+}
 const IdDataSpec cdbtcl_rwdatabases= {
   "cdb-rwdb", "cdb-openrwdatabases-table", destroy_cdbrw_idtabcb
 };
@@ -183,7 +213,7 @@ static int acquire_lock(Tcl_Interp *ip, Pathbuf *pb, int *lockfd_r) {
   /* Remove r where umask would remove w;
    * eg umask intending 0664 here gives 0660 */
   
-  *lockfd_r= open(pathbuf_sfx(pb,".lock"), O_RDONLY|O_CREAT, lockmode);
+  *lockfd_r= open(pathbuf_sfx(pb,".lock"), O_RDWR|O_CREAT, lockmode);
   if (*lockfd_r < 0)
     return cht_posixerr(ip, errno, "could not open/create lockfile");
 
@@ -200,9 +230,11 @@ static int acquire_lock(Tcl_Interp *ip, Pathbuf *pb, int *lockfd_r) {
     else return cht_posixerr(ip, errno, "unexpected error from fcntl while"
 			     " acquiring lock");
   }
+
+  return TCL_OK;
 }
 
-/*---------- Log reading ----------*/
+/*---------- Log reading and writing ----------*/
 
 static int readlognum(FILE *f, int delim, int *num_r) {
   int c;
@@ -221,19 +253,23 @@ static int readlognum(FILE *f, int delim, int *num_r) {
   *p= 0;
 
   errno=0; ul= strtoul(numbuf, &ep, 10);
-  if (*ep || errno || ul >= INT_MAX/2) return -2;
+  if (*ep || errno || ul >= KEYLEN_MAX) return -2;
   *num_r= ul;
   return 0;
 }
 
 static int readstorelogrecord(FILE *f, HashTable *ht,
+			      int (*omitfn)(const HashValue*,
+					    struct ht_forall_ctx *ctx),
+			      struct ht_forall_ctx *ctx,
 			      void (*updatefn)(HashTable*, const char*,
 					       HashValue*)) {
   /* returns:
-   *     0 for OK
-   *     -1 eof
-   *     -2 corrupt or error
-   *     -3 got newline indicating end
+   *      0     for OK
+   *     -1     eof
+   *     -2     corrupt or error
+   *     -3     got newline indicating end
+   *     >0     value from omitfn
    */
   int keylen, vallen;
   char *key;
@@ -241,7 +277,7 @@ static int readstorelogrecord(FILE *f, HashTable *ht,
   int c, rc, r;
 
   c= getc(f);
-  if (c==EOF) { if (feof(f)) return -1; return -2; }
+  if (c==EOF) { return feof(f) ? -1 : -2; }
   if (c=='\n') return -3;
   if (c!='+') return -2;
 
@@ -262,9 +298,14 @@ static int readstorelogrecord(FILE *f, HashTable *ht,
   r= fread(htv_fillptr(val), 1,vallen, f);
   if (r!=vallen) goto x2_free_keyval;
 
-  updatefn(ht, key, val);
+  c= getc(f);  if (c!='\n') goto x2_free_keyval;
+
+  rc= omitfn ? omitfn(val, ctx) : TCL_OK;
+  if (rc) { assert(rc>0); TFREE(val); }
+  else updatefn(ht, key, val);
+  
   TFREE(key);
-  return TCL_OK;
+  return rc;
 
  x2_free_keyval:
   TFREE(val);
@@ -272,36 +313,64 @@ static int readstorelogrecord(FILE *f, HashTable *ht,
   return -2;
 }
 
+static int writerecord(FILE *f, const char *key, const HashValue *val) {
+  int r;
+
+  r= fprintf(f, "+%d,%d:%s->", (int)strlen(key), val->len, key);
+  if (r<0) return -1;
+  
+  r= fwrite(val->data, 1, val->len, f);
+  if (r != val->len) return -1;
+
+  r= putc('\n', f);
+  if (r==EOF) return -1;
+
+  return 0;
+}
+
 /*---------- Creating ----------*/
 
 int cht_do_cdbwr_create_empty(ClientData cd, Tcl_Interp *ip,
 			      const char *pathb) {
-  static const char *const toremoves[]= {
-    ".main", ".cdb", ".log", ".tmp", 0
-  };
+  static const char *const toremoves[]= { ".cdb", ".jrn", ".tmp", 0 };
 
-  Pathbuf pb;
-  int lock_fd=-1, fd=-1, rc, r;
+  Pathbuf pb, pbmain;
+  int lock_fd=-1, rc, r;
+  FILE *f= 0;
   const char *const *toremove;
+  struct stat stab;
 
   pathbuf_init(&pb, pathb);
+  pathbuf_init(&pbmain, pathb);
+
   rc= acquire_lock(ip, &pb, &lock_fd);  if (rc) goto x_rc;
-  
-  fd= open(pathbuf_sfx(&pb, ".main"), O_RDWR|O_CREAT|O_EXCL, 0666);
-  if (fd <= 0) PE("create new database file");
+
+  r= lstat(pathbuf_sfx(&pbmain, ".main"), &stab);
+  if (!r) { rc= cht_staticerr(ip, "database already exists during creation",
+			      "CDB ALREADY-EXISTS");  goto x_rc; }
+  if (errno != ENOENT) PE("check for existing database .main during creation");
 
   for (toremove=toremoves; *toremove; toremove++) {
-    r= remove(*toremove);
+    r= remove(pathbuf_sfx(&pb, *toremove));
     if (r && errno != ENOENT)
       PE("delete possible spurious file during creation");
   }
   
+  f= fopen(pathbuf_sfx(&pb, ".tmp"), "w");
+  if (!f) PE("create new database .tmp");  
+  r= putc('\n', f);  if (r==EOF) PE("write sentinel to new database .tmp");
+  r= fclose(f);  f=0;  if (r) PE("close new database .tmp during creation");
+
+  r= rename(pb.buf, pbmain.buf);
+  if (r) PE("install new database .tmp as .main (finalising creation)");
+  
   rc= TCL_OK;
 
  x_rc:
-  maybe_close(fd);
+  if (f) fclose(f);
   maybe_close(lock_fd);
   pathbuf_free(&pb);
+  pathbuf_free(&pbmain);
   return rc;
 }
 
@@ -309,7 +378,17 @@ int cht_do_cdbwr_create_empty(ClientData cd, Tcl_Interp *ip,
 
 static int infocbv3(Tcl_Interp *ip, Rw *rw, const char *arg1,
 		    const char *arg2fmt, const char *arg3, va_list al) {
-  abort();
+  Tcl_Obj *aa[3];
+  int na;
+  char buf[200];
+  vsnprintf(buf, sizeof(buf), arg2fmt, al);
+
+  na= 0;
+  aa[na++]= cht_ret_string(ip, arg1);
+  aa[na++]= cht_ret_string(ip, buf);
+  if (arg3) aa[na++]= cht_ret_string(ip, arg3);
+  
+  return cht_scriptinv_invoke_fg(&rw->on_info, na, aa);
 }
   
 static int infocb3(Tcl_Interp *ip, Rw *rw, const char *arg1,
@@ -334,8 +413,22 @@ static int infocb(Tcl_Interp *ip, Rw *rw, const char *arg1,
   
 /*---------- Opening ----------*/
 
+static int cdbinit(Tcl_Interp *ip, Rw *rw) {
+  /* On entry, cdb_fd >=0 but cdb is _undefined_/
+   * On exit, either cdb_fd<0 or cdb is initialised */
+  int r, rc;
+  
+  r= cdb_init(&rw->cdb, rw->cdb_fd);
+  if (r) {
+    rc= cht_posixerr(ip, errno, "failed to initialise cdb reader");
+    close(rw->cdb_fd);  rw->cdb_fd= -1;  return rc;
+  }
+  return TCL_OK;
+}
+
 int cht_do_cdbwr_open(ClientData cd, Tcl_Interp *ip, const char *pathb,
-		      Tcl_Obj *on_info, int maxage, void **result) {
+		      Tcl_Obj *on_info, Tcl_Obj *on_lexminval,
+		      void **result) {
   const Cdbwr_SubCommand *subcmd= cd;
   int r, rc, mainfd=-1;
   Rw *rw;
@@ -343,15 +436,23 @@ int cht_do_cdbwr_open(ClientData cd, Tcl_Interp *ip, const char *pathb,
   off_t logrecstart, logjunkpos;
 
   rw= TALLOC(sizeof(*rw));
+  rw->ix= -1;
   ht_setup(&rw->logincore);
+  cht_scriptinv_init(&rw->on_info);
+  cht_scriptinv_init(&rw->on_lexminval);
   rw->cdb_fd= rw->lock_fd= -1;  rw->logfile= 0;
-  rw->maxage= maxage;
   pathbuf_init(&rw->pbsome, pathb);
   pathbuf_init(&rw->pbother, pathb);
   rw->autocompact= 1;
 
+  rc= cht_scriptinv_set(&rw->on_info, ip, on_info, 0);
+  if (rc) goto x_rc;
+
+  rc= cht_scriptinv_set(&rw->on_lexminval, ip, on_lexminval, 0);
+  if (rc) goto x_rc;
+
   mainfd= open(pathbuf_sfx(&rw->pbsome,".main"), O_RDONLY);
-  if (mainfd<0) PE("open exist3ing database file .main");
+  if (mainfd<0) PE("open existing database file .main");
   rc= acquire_lock(ip, &rw->pbsome, &rw->lock_fd);  if (rc) goto x_rc;
 
   r= fstat(mainfd, &stab);  if (r) PE("fstat .main");
@@ -359,14 +460,10 @@ int cht_do_cdbwr_open(ClientData cd, Tcl_Interp *ip, const char *pathb,
 
   rw->cdb_fd= open(pathbuf_sfx(&rw->pbsome,".cdb"), O_RDONLY);
   if (rw->cdb_fd >=0) {
-    r= cdb_init(&rw->cdb, rw->cdb_fd);
-    if (r) {
-      rc= cht_posixerr(ip, errno, "failed to initialise cdb reader");
-      close(rw->cdb_fd);  rw->cdb_fd= -1;  goto x_rc;
-    }
+    rc= cdbinit(ip, rw);  if (rc) goto x_rc;
   } else if (errno == ENOENT) {
-    if (rw->mainsz) {
-      rc= cht_staticerr(ip, ".cdb does not exist but .main is nonempty -"
+    if (rw->mainsz > 1) {
+      rc= cht_staticerr(ip, ".cdb does not exist but .main is >1byte -"
 			" .cdb must have been accidentally deleted!",
 			"CDB CDBMISSING");
       goto x_rc;
@@ -376,24 +473,24 @@ int cht_do_cdbwr_open(ClientData cd, Tcl_Interp *ip, const char *pathb,
     PE("open .cdb");
   }
 
-  rw->logfile= fopen(pathbuf_sfx(&rw->pbsome,".log"), "r+");
+  rw->logfile= fopen(pathbuf_sfx(&rw->pbsome,".jrn"), "r+");
   if (!rw->logfile) {
-    if (errno != ENOENT) PE("failed to open .log during open");
+    if (errno != ENOENT) PE("failed to open .jrn during open");
     rw->logfile= fopen(rw->pbsome.buf, "w");
-    if (!rw->logfile) PE("create .log during (clean) open");
+    if (!rw->logfile) PE("create .jrn during (clean) open");
   } else { /* rw->logfile */
     r= fstat(fileno(rw->logfile), &stab);
-    if (r==-1) PE("fstat .log during open");
+    if (r==-1) PE("fstat .jrn during open");
     rc= infocb(ip, rw, "open-dirty-start", "log=%luby",
 	       (unsigned long)stab.st_size);
     if (rc) goto x_rc;
 
     for (;;) {
       logrecstart= ftello(rw->logfile);
-      if (logrecstart < 0) PE("ftello .log during (dirty) open");
-      r= readstorelogrecord(rw->logfile, &rw->logincore, ht_update);
+      if (logrecstart < 0) PE("ftello .jrn during (dirty) open");
+      r= readstorelogrecord(rw->logfile, &rw->logincore, 0,0, ht_update);
       if (ferror(rw->logfile)) {
-	rc= cht_posixerr(ip, errno, "error reading .log during (dirty) open");
+	rc= cht_posixerr(ip, errno, "error reading .jrn during (dirty) open");
 	goto x_rc;
       }
       if (r==-1) {
@@ -401,7 +498,7 @@ int cht_do_cdbwr_open(ClientData cd, Tcl_Interp *ip, const char *pathb,
       } else if (r==-2 || r==-3) {
 	char buf[100];
 	logjunkpos= ftello(rw->logfile);
-	if(logjunkpos<0) PE("ftello .log during report of junk in dirty open");
+	if(logjunkpos<0) PE("ftello .jrn during report of junk in dirty open");
 
 	snprintf(buf,sizeof(buf), "CDB SYNTAX LOG %lu %lu",
 		 (unsigned long)logjunkpos, (unsigned long)logrecstart);
@@ -410,7 +507,7 @@ int cht_do_cdbwr_open(ClientData cd, Tcl_Interp *ip, const char *pathb,
 	  Tcl_SetObjErrorCode(ip, Tcl_NewStringObj(buf,-1));
 	  snprintf(buf,sizeof(buf),"%lu",(unsigned long)logjunkpos);
 	  Tcl_ResetResult(ip);
-	  Tcl_AppendResult(ip, "syntax error (junk) in .log during"
+	  Tcl_AppendResult(ip, "syntax error (junk) in .jrn during"
 			   " (dirty) open, at file position ", buf, (char*)0);
 	  rc= TCL_ERROR;
 	  goto x_rc;
@@ -420,10 +517,10 @@ int cht_do_cdbwr_open(ClientData cd, Tcl_Interp *ip, const char *pathb,
 	if (rc) goto x_rc;
 
 	r= fseeko(rw->logfile, logrecstart, SEEK_SET);
-	if (r) PE("failed to fseeko .log before junk during dirty open");
+	if (r) PE("failed to fseeko .jrn before junk during dirty open");
 
 	r= ftruncate(fileno(rw->logfile), logrecstart);
-	if (r) PE("ftruncate .log to chop junk during dirty open");
+	if (r) PE("ftruncate .jrn to chop junk during dirty open");
       } else {
 	assert(!r);
       }
@@ -437,64 +534,135 @@ int cht_do_cdbwr_open(ClientData cd, Tcl_Interp *ip, const char *pathb,
 
  x_rc:
   rw_close(0,rw);
+  TFREE(rw);
   maybe_close(mainfd);
   return rc;
 }
 
-/*---------- Compacting ----------*/
+int cht_do_cdbwr_open_okjunk(ClientData cd, Tcl_Interp *ip, const char *pathb,
+		      Tcl_Obj *on_info, Tcl_Obj *on_lexminval,
+		      void **result) {
+  return cht_do_cdbwr_open(cd,ip,pathb,on_info,on_lexminval,result);
+}
+
+/*==================== COMPACTION ====================*/
+
+struct ht_forall_ctx {
+  struct cdb_make cdbm;
+  FILE *mainfile;
+  long *reccount;
+  int lexminvall;
+  const char *lexminval; /* may be invalid if lexminvall <= 0 */
+};
 
-static int compact_core(Tcl_Interp *ip, Rw *rw, unsigned long logsize) {
+/*---------- helper functions ----------*/
+
+static int expiredp(const HashValue *val, struct ht_forall_ctx *a) {
+  int r, l;
+  if (!val->len || a->lexminvall<=0) return 0;
+  l= val->len < a->lexminvall ? val->len : a->lexminvall;
+  r= memcmp(val->data, a->lexminval, l);
+  if (r>0) return 0;
+  if (r<0) return 1;
+  return val->len < a->lexminvall;
+}
+
+static int delete_ifexpired(const char *key, HashValue *val,
+			    struct ht_forall_ctx *a) {
+  if (!expiredp(val, a)) return 0;
+  val->len= 0;
+  /* we don't actually need to realloc it to free the memory because
+   * this will shortly all be deleted as part of the compaction */
+  return 0;
+}
+
+static int addto_cdb(const char *key, HashValue *val,
+		     struct ht_forall_ctx *a) {
+  return cdb_make_add(&a->cdbm, key, strlen(key), val->data, val->len);
+}
+
+static int addto_main(const char *key, HashValue *val,
+		      struct ht_forall_ctx *a) {
+  (*a->reccount)++;
+  return writerecord(a->mainfile, key, val);
+}
+
+/*---------- compact main entrypoint ----------*/
+
+static int compact_core(Tcl_Interp *ip, Rw *rw, unsigned long logsz,
+			long *reccount_r) {
   /* creates new .cdb and .main
    * closes logfile
-   * leaves .log with old data
+   * leaves .jrn with old data
    * leaves cdb fd open onto old db
    * leaves logincore full of crap
    */
   int r, rc;
   int cdbfd, cdbmaking;
-  off_t errpos;
+  off_t errpos, newmainsz;
   char buf[100];
-  
-  struct ht_forall_ctx {
-    struct cdb_make cdbm;
-    FILE *mainfile;
-    int count;
-  } a;
+  Tcl_Obj *res;
+  struct ht_forall_ctx a;
 
   a.mainfile= 0;
   cdbfd= -1;
   cdbmaking= 0;
+  *reccount_r= 0;
+  a.reccount= reccount_r;
 
   r= fclose(rw->logfile);
-  if (r) { rc= cht_posixerr(ip, errno, "data loss!  failed to fclose"
-			    " logfile during compact");  goto x_rc; }
   rw->logfile= 0;
+  if (r) { rc= cht_posixerr(ip, errno, "probable data loss!  failed to fclose"
+			    " logfile during compact");  goto x_rc; }
   
   rc= infocb(ip, rw, "compact-start", "log=%luby main=%luby",
-	     logsize, (unsigned long)rw->mainsz);
+	     logsz, (unsigned long)rw->mainsz);
   if (rc) goto x_rc;
 
+  if (cht_scriptinv_interp(&rw->on_lexminval)) {
+    rc= cht_scriptinv_invoke_fg(&rw->on_lexminval, 0,0);
+    if (rc) goto x_rc;
+
+    res= Tcl_GetObjResult(ip);  assert(res);
+    a.lexminval= Tcl_GetStringFromObj(res, &a.lexminvall);
+    assert(a.lexminval);
+
+    /* we rely not calling Tcl_Eval during the actual compaction;
+     * if we did Tcl_Eval then the interp result would be trashed.
+     */
+    rc= ht_forall(&rw->logincore, delete_ifexpired, &a);
+
+  } else {
+    a.lexminvall= 0;
+  }
+
   /* merge unsuperseded records from main into hash table */
 
   a.mainfile= fopen(pathbuf_sfx(&rw->pbsome,".main"), "r");
   if (!a.mainfile) PE("failed to open .main for reading during compact");
 
   for (;;) {
-    r= readstorelogrecord(a.mainfile, &rw->logincore, ht_maybeupdate);
+    r= readstorelogrecord(a.mainfile, &rw->logincore,
+			  expiredp, &a,
+			  ht_maybeupdate);
     if (ferror(a.mainfile)) { rc= cht_posixerr(ip, errno, "error reading"
-                         " .main during compact"); goto x_rc;
-    }
+                         " .main during compact"); goto x_rc; }
     if (r==-3) {
       break;
     } else if (r==-1 || r==-2) {
       errpos= ftello(a.mainfile);
       if (errpos<0) PE("ftello .main during report of syntax error");
-      snprintf(buf,sizeof(buf), "CDB SYNTAX MAIN %lu", (unsigned long)errpos);
+      snprintf(buf,sizeof(buf), "CDB %s MAIN %lu",
+	       r==-1 ? "TRUNCATED" : "SYNTAX", (unsigned long)errpos);
       Tcl_SetObjErrorCode(ip, Tcl_NewStringObj(buf,-1));
       snprintf(buf,sizeof(buf), "%lu", (unsigned long)errpos);
       Tcl_ResetResult(ip);
-      Tcl_AppendResult(ip, "syntax error in .main during"
-		       " compact, at file position ", buf, (char*)0);
+      Tcl_AppendResult(ip,
+		       r==-1 ? "unexpected eof (truncated file)"
+		       " in .main during compact, at file position "
+		       : "syntax error"
+		       " in .main during compact, at file position ",
+		       buf, (char*)0);
       rc= TCL_ERROR;
       goto x_rc;
     } else {
@@ -513,10 +681,10 @@ static int compact_core(Tcl_Interp *ip, Rw *rw, unsigned long logsize) {
   if (r) PE("cdb_make_start during compact");
   cdbmaking= 1;
 
-  r= ht_forall(&rw->logincore, addto_cdb, &addctx);
+  r= ht_forall(&rw->logincore, addto_cdb, &a);
   if (r) PE("cdb_make_add during compact");
 
-  r= cdb_make_finish(&a.cdbm, cdbfd);
+  r= cdb_make_finish(&a.cdbm);
   if(r) PE("cdb_make_finish during compact");
   cdbmaking= 0;
 
@@ -532,14 +700,19 @@ static int compact_core(Tcl_Interp *ip, Rw *rw, unsigned long logsize) {
   a.mainfile= fopen(pathbuf_sfx(&rw->pbsome,".tmp"), "w");
   if (!a.mainfile) PE("create .tmp for new main during compact");
 
-  a.count= 0;
-  r= ht_forall(&rw->logincore, addto_main, a.mainfile);
-  if (r) { rc= cht_posixerr(ip, r, "error writing to new .main"
+  r= ht_forall(&rw->logincore, addto_main, &a);
+  if (r) { rc= cht_posixerr(ip, errno, "error writing to new .main"
 			    " during compact");  goto x_rc; }
+
+  r= putc('\n', a.mainfile);
+  if (r==EOF) PE("write trailing \n to main during compact");
   
   r= fflush(a.mainfile);  if (r) PE("fflush new main during compact");
   r= fdatasync(fileno(a.mainfile));
   if (r) PE("fdatasync new main during compact");
+
+  newmainsz= ftello(a.mainfile);
+  if (newmainsz<0) PE("ftello new main during compact");
   
   r= fclose(a.mainfile);  if (r) PE("fclose new main during compact");
   a.mainfile= 0;
@@ -547,53 +720,258 @@ static int compact_core(Tcl_Interp *ip, Rw *rw, unsigned long logsize) {
   r= rename(rw->pbsome.buf, pathbuf_sfx(&rw->pbother,".main"));
   if (r) PE("install new .main during compact");
 
+  rw->mainsz= newmainsz;
+
   /* done! */
   
-  rc= infocb(ip, rw, "compact-end", "log=%luby main=%luby",
-	     logsize, (unsigned long)rw->mainsz);
+  rc= infocb(ip, rw, "compact-end", "main=%luby nrecs=%ld",
+	     (unsigned long)rw->mainsz, *a.reccount);
   if (rc) goto x_rc;
 
-  rc= TCL_OK;
+  return rc;
+
 x_rc:
-  if (mainfile) fclose(mainfile);
-  if (cdbmaking) cdb_make_finish(&a.cdbm, cdbfd);
+  if (a.mainfile) fclose(a.mainfile);
+  if (cdbmaking) cdb_make_finish(&a.cdbm);
   maybe_close(cdbfd);
   remove(pathbuf_sfx(&rw->pbsome,".tmp")); /* for tidyness */
+  return rc;
 }
-  
-static void compact_forclose(Tcl_Interp *ip, Rw *rw) {
+
+/*---------- Closing ----------*/
+
+static int compact_forclose(Tcl_Interp *ip, Rw *rw, long *reccount_r) {
   off_t logsz;
-  int rc;
+  int r, rc;
 
   logsz= ftello(rw->logfile);
   if (logsz < 0) PE("ftello logfile (during tidy close)");
 
-  rc= compact_core(ip, rw, logsz);  if (rc) goto x_rc;
+  rc= compact_core(ip, rw, logsz, reccount_r);  if (rc) goto x_rc;
+
+  r= remove(pathbuf_sfx(&rw->pbsome,".jrn"));
+  if (r) PE("remove .jrn (during tidy close)");
 
-  r= remove(pathbuf_sfx(&rw->pbsome,".log"));
-  if (r) PE("remove .log (during tidy close)");
+  return TCL_OK;
+
+x_rc: return rc;
 }
   
 int cht_do_cdbwr_close(ClientData cd, Tcl_Interp *ip, void *rw_v) {
   Rw *rw= rw_v;
-  int rc, compact_rc, infocb_rc;
-
-  if (rw->autocompact) compact_rc= compact_forclose(ip, rw);
-  else compact_rc= TCL_OK;
+  int rc, rc_close;
+  long reccount= -1;
+  off_t logsz;
 
-  rc= rw_close(ip,rw);
-  infocb_rc= infocb_close(rw);
+  if (rw->autocompact) rc= compact_forclose(ip, rw, &reccount);
+  else rc= TCL_OK;
+
+  if (!rc) {
+    if (rw->logfile) {
+      logsz= ftello(rw->logfile);
+      if (logsz < 0)
+	rc= cht_posixerr(ip, errno, "ftell logfile during close info");
+      else
+	rc= infocb(ip, rw, "close", "main=%luby log=%luby",
+		   rw->mainsz, logsz);
+    } else if (reccount>=0) {
+      rc= infocb(ip, rw, "close", "main=%luby nrecs=%ld",
+		 rw->mainsz, reccount);
+    } else {
+      rc= infocb(ip, rw, "close", "main=%luby", rw->mainsz);
+    }
+  }
+  rc_close= rw_close(ip,rw);
+  if (rc_close) rc= rc_close;
   
   cht_tabledataid_disposing(ip, rw_v, &cdbtcl_rwdatabases);
-  if (!rc) rc= compact_rc;
-  if (!rc) rc= infocb_rc;
+  TFREE(rw);
+  return rc;
+}
+
+/*---------- Other compaction-related entrypoints ----------*/
+
+static int compact_keepopen(Tcl_Interp *ip, Rw *rw, int force) {
+  off_t logsz;
+  long reccount;
+  int rc, r;
+
+  logsz= ftello(rw->logfile);
+  if (logsz < 0) return cht_posixerr(ip, errno, "ftell .jrn"
+				       " during compact check or force");
+
+  if (!force && logsz < rw->mainsz / 3 + 1000) return TCL_OK;
+  /* Test case:                    ^^^ testing best value for this
+   *   main=9690434by nrecs=122803  read all in one go
+   *  no autocompact, :    6.96user 0.68system 0:08.93elapsed
+   *  auto, mulitplier 2:  7.10user 0.79system 0:09.54elapsed
+   *  auto, unity:         7.80user 0.98system 0:11.84elapsed
+   *  auto, divisor  2:    8.23user 1.05system 0:13.30elapsed
+   *  auto, divisor  3:    8.55user 1.12system 0:12.88elapsed
+   *  auto, divisor  5:    9.95user 1.43system 0:15.72elapsed
+   */
+
+  rc= compact_core(ip, rw, logsz, &reccount);  if (rc) goto x_rc;
+
+  maybe_close(rw->cdb_fd);
+  rw->cdb_fd= -1;
+  ht_destroy(&rw->logincore);
+  ht_setup(&rw->logincore);
+
+  rw->cdb_fd= open(pathbuf_sfx(&rw->pbsome,".cdb"), O_RDONLY);
+  if (rw->cdb_fd < 0) PE("reopen .cdb after compact");
+
+  rc= cdbinit(ip, rw);  if (rc) goto x_rc;
+
+  rw->logfile= fopen(pathbuf_sfx(&rw->pbsome,".jrn"), "w");
+  if (!rw->logfile) PE("reopen .jrn after compact");
+
+  r= fsync(fileno(rw->logfile));  if (r) PE("fsync .jrn after compact reopen");
+
+  return TCL_OK;
+
+x_rc:
+  /* doom! all updates fail after this (because rw->logfile is 0), and
+   * we may be using a lot more RAM than would be ideal.  Program will
+   * have to reopen if it really wants sanity. */
+  return rc;
+}
+
+int cht_do_cdbwr_compact_force(ClientData cd, Tcl_Interp *ip, void *rw_v) {
+  return compact_keepopen(ip, rw_v, 1);
+}
+int cht_do_cdbwr_compact_check(ClientData cd, Tcl_Interp *ip, void *rw_v) {
+  return compact_keepopen(ip, rw_v, 0);
+}
+
+int cht_do_cdbwr_compact_explicit(ClientData cd, Tcl_Interp *ip, void *rw_v) {
+  Rw *rw= rw_v;
+  rw->autocompact= 0;
+  return TCL_OK;
+}
+int cht_do_cdbwr_compact_auto(ClientData cd, Tcl_Interp *ip, void *rw_v) {
+  Rw *rw= rw_v;
+  rw->autocompact= 1;
+  return TCL_OK;
+}
+
+/*---------- Updateing ----------*/
+
+static int update(Tcl_Interp *ip, Rw *rw, const char *key,
+		  const Byte *data, int dlen) {
+  HashValue *val;
+  const char *failed;
+  int rc, r;
+  off_t recstart;
+
+  if (strlen(key) >= KEYLEN_MAX)
+    return cht_staticerr(ip, "key too long", "CDB KEYOVERFLOW");
+
+  if (!rw->logfile) return cht_staticerr
+    (ip, "failure during previous compact or error recovery;"
+     " cdbwr must be closed and reopened before any further updates",
+     "CDB BROKEN");
+  
+  recstart= ftello(rw->logfile);
+  if (recstart < 0)
+    return cht_posixerr(ip, errno, "failed to ftello .jrn during update");
+
+  val= htv_prep(dlen);  assert(val);
+  memcpy(htv_fillptr(val), data, dlen);
+
+  r= writerecord(rw->logfile, key, val);
+  if (!r) r= fflush(rw->logfile);
+  if (r) PE("write update to logfile");
+
+  ht_update(&rw->logincore, key, val);
+
+  if (!rw->autocompact) return TCL_OK;
+  return compact_keepopen(ip, rw, 0);
+
+ x_rc:
+  TFREE(val);
+  assert(rc);
+
+  /* Now, we have to try to sort out the journal so that it's
+   * truncated and positioned to where this abortively-written record
+   * started, with no buffered output and the error indicator clear.
+   *
+   * There seems to be no portable way to ensure the buffered unwritten
+   * output is discarded, so we close and reopen the stream.
+   */
+  fclose(rw->logfile);
+
+  rw->logfile= fopen(pathbuf_sfx(&rw->pbsome,".jrn"), "r+");
+  if (!rw->logfile) { failed= "fopen"; goto reset_fail; }
+
+  r= ftruncate(fileno(rw->logfile), recstart);
+  if (r) { failed= "ftruncate"; goto reset_fail; }
+
+  r= fseeko(rw->logfile, recstart, SEEK_SET);
+  if (r) { failed= "fseeko"; goto reset_fail; }
+
   return rc;
+
+ reset_fail:
+  Tcl_AppendResult(ip, " (additionally, ", failed, " failed"
+		   " in error recovery: ", strerror(errno), ")", (char*)0);
+  if (rw->logfile) { fclose(rw->logfile); rw->logfile= 0; }
+
+  return rc;
+}  
+
+int cht_do_cdbwr_update(ClientData cd, Tcl_Interp *ip,
+			void *rw_v, const char *key, Tcl_Obj *value) {
+  int dlen;
+  const char *data;
+  data= Tcl_GetStringFromObj(value, &dlen);  assert(data);
+  return update(ip, rw_v, key, data, dlen);
+}
+
+int cht_do_cdbwr_update_hb(ClientData cd, Tcl_Interp *ip,
+			   void *rw_v, const char *key, HBytes_Value value) {
+  return update(ip, rw_v, key, cht_hb_data(&value), cht_hb_len(&value));
+}
+
+int cht_do_cdbwr_delete(ClientData cd, Tcl_Interp *ip, void *rw_v,
+			const char *key) {
+  return update(ip, rw_v, key, 0, 0);
 }
 
+/*---------- Lookups ----------*/
+
+static int lookup_rw(Tcl_Interp *ip, void *rw_v, const char *key,
+		    const Byte **data_r, int *len_r /* -1 => notfound */) {
+  Rw *rw= rw_v;
+  const HashValue *val;
+
+  val= ht_lookup(&rw->logincore, key);
+  if (val) {
+    if (val->len) { *data_r= val->data; *len_r= val->len; return TCL_OK; }
+    else { *data_r= 0; *len_r= -1; return TCL_OK; }
+  }
+
+  return cht_cdb_lookup_cdb(ip, &rw->cdb, key, strlen(key), data_r, len_r);
+} 
+
+int cht_do_cdbwr_lookup(ClientData cd, Tcl_Interp *ip, void *rw_v,
+			const char *key, Tcl_Obj *def,
+			Tcl_Obj **result) {
+  const Byte *data;
+  int dlen, r;
+  
+  r= lookup_rw(ip, rw_v, key, &data, &dlen);  if (r) return r;
+  return cht_cdb_donesomelookup(ip, rw_v, def, result, data, dlen,
+				cht_cdb_storeanswer_string);
+}
   
-int cht_do_cdbwr_lookup(ClientData cd, Tcl_Interp *ip, void *db, Tcl_Obj *key, Tcl_Obj **result);
-int cht_do_cdbwr_lookup_hb(ClientData cd, Tcl_Interp *ip, void *db, HBytes_Value key, HBytes_Value *result);
-int cht_do_cdbwr_update(ClientData cd, Tcl_Interp *ip, void *db, Tcl_Obj *key, Tcl_Obj *value);
-int cht_do_cdbwr_update_hb(ClientData cd, Tcl_Interp *ip, void *db, HBytes_Value key, HBytes_Value value);
-int cht_do_cdbwr_update_quick(ClientData cd, Tcl_Interp *ip, void *db, Tcl_Obj *key, Tcl_Obj *value);
-int cht_do_cdbwr_update_quick_hb(ClientData cd, Tcl_Interp *ip, void *db, HBytes_Value key, HBytes_Value value);
+int cht_do_cdbwr_lookup_hb(ClientData cd, Tcl_Interp *ip, void *rw_v,
+			   const char *key, Tcl_Obj *def,
+			   Tcl_Obj **result) {
+  const Byte *data;
+  int dlen, r;
+  
+  r= lookup_rw(ip, rw_v, key, &data, &dlen);  if (r) return r;
+  return cht_cdb_donesomelookup(ip, rw_v, def, result, data, dlen,
+				cht_cdb_storeanswer_hb);
+}