adjust divisor

[chiark-tcl.git] / cdb / writeable.c

diff --git a/cdb/writeable.c b/cdb/writeable.c
index 15ffed2caffc6ae1312f3a3f5e59a7d792d78d0f..d5c5c5ba8272c4493aa20f0d4fcd62ad1c9fd165 100644 (file)
--- a/cdb/writeable.c
+++ b/cdb/writeable.c
@@ -1,37 +1,35 @@
 /**/
 
 /**/
 

-#include <nettle/md4.h>
-

 #include "chiark_tcl_cdb.h"
 
 #include "chiark_tcl_cdb.h"
 

+#define ftello ftell
+#define fseeko fseek

 
 

+/*---------- Forward declarations ----------*/

 
 struct ht_forall_ctx;
 
 
 struct ht_forall_ctx;
 

-
+/*---------- Useful routines ----------*/

 
 static void maybe_close(int fd) {
   if (fd>=0) close(fd);
 }
 
 
 static void maybe_close(int fd) {
   if (fd>=0) close(fd);
 }
 

-#define PE do{                                                 \
-    rc= cht_posixerr(ip, errno, "failed to " PE); goto x_rc;   \
-  }while(0)
+/*==================== Subsystems and subtypes ====================*/

 
 /*---------- Pathbuf ----------*/
 
 
 /*---------- Pathbuf ----------*/
 

-typedef struct {
+typedef struct Pathbuf {

   char *buf, *sfx;
 } 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);
 
 static void pathbuf_init(Pathbuf *pb, const char *pathb) {
   int l= strlen(pathb);

-  pb->buf= TALLOC(l + 4);
+  pb->buf= TALLOC(l + MAX_SUFFIX + 1);

   memcpy(pb->buf, pathb, l);
   pb->sfx= pb->buf + l;
   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);
 }
 static const char *pathbuf_sfx(Pathbuf *pb, const char *suffix) {
   assert(strlen(suffix) <= MAX_SUFFIX);


@@ -47,75 +45,71 @@ static void pathbuf_free(Pathbuf *pb) {
 
 typedef struct HashTable {
   Tcl_HashTable t;
 
 typedef struct HashTable {
   Tcl_HashTable t;

+  Byte padding[128]; /* allow for expansion by Tcl, urgh */

   Byte confound[16];
 } HashTable;
 
   Byte confound[16];
 } HashTable;
 

-typedef struct HashDatum {
+typedef struct HashValue {

   int len;
   Byte data[1];
   int len;
   Byte data[1];

-} HashDatum;
-
-static unsigned int hkt_hash(Tcl_HashTable *tht, void *key_v) {
-  HashTable *ht= (void*)tht;
-  const HashDatum *key= key_v;
-
-  struct md4_ctx mdc;
-  Byte mdr[MD4_DIGEST_SIZE];
-  
-  md4_init(&mdc);
-  md4_update(&mdc, sizeof(ht->confound), ht->confound);
-  md4_update(&mdc, key->len, key->data);
-  md4_digest(&mdc, sizeof(mdr), mdr);
-  assert(sizeof(int) <= MD4_DIGEST_SIZE);
-  return *(int*)md4;
-}
+} HashValue;

 
 

-static const struct Tcl_HashKeyType ht_keytype= {
-  TCL_HASH_KEY_TYPE_VERSION, 0,
-  htk_hash, htk_compare, 0, 0
-}
-
-static HashDatum *htd_prep(int len) {
-  HashDatum *hd;
-  hd= TALLOC(offsetof(HashDatum, data) + len);
+static HashValue *htv_prep(int len) {
+  HashValue *hd;
+  hd= TALLOC((hd->data - (Byte*)hd) + len);

   hd->len= len;
   hd->len= len;

+  return hd;

 }  
 }  

-static Byte *htd_fillptr(HashDatum *hd) {
+static Byte *htv_fillptr(HashValue *hd) {

   return hd->data;
 }
   return hd->data;
 }

-static void htd_fill(HashDatum *hd, const Byte *data) {
-  memcpy(hd->data, data, hd->len);
-}

 
 

-static int ht_setup(HashTable *ht) {
-  rc= cht_get_urandom(ip, ht->confound, sizeof(ht->confound));
-  if (rc) return rc;
-  
-  Tcl_InitCustomHashTable(&ht->t, TCL_CUSTOM_PTR_KEYS, &ht_keytype);
-  return TCL_OK;
+static void ht_setup(HashTable *ht) {
+  Tcl_InitHashTable(&ht->t, TCL_STRING_KEYS);

 }
 }

-static void ht_update(HashTable *ht, HashDatum *key_eat, HashDatum *val_eat) {
+static void ht_update(HashTable *ht, const char *key, HashValue *val_eat) {

   Tcl_HashEntry *he;
   int new;
 
   Tcl_HashEntry *he;
   int new;
 

-  he= Tcl_CreateHashEntry(&ht->t, key_eat, &new);
-    /* eats the key! (since the data structure owns the memory) */
+  he= Tcl_CreateHashEntry(&ht->t, (char*)key, &new);

   if (!new) TFREE(Tcl_GetHashValue(he));
   Tcl_SetHashValue(he, val_eat);
   if (!new) TFREE(Tcl_GetHashValue(he));
   Tcl_SetHashValue(he, val_eat);

+    /* eats the value since the data structure owns the memory */
+}
+static void ht_maybeupdate(HashTable *ht, const char *key,
+                          HashValue *val_eat) {
+  /* like ht_update except does not overwrite existing values */
+  Tcl_HashEntry *he;
+  int new;
+
+  he= Tcl_CreateHashEntry(&ht->t, (char*)key, &new);
+  if (!new) { TFREE(val_eat); return; }
+  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,
 }
 
 static int ht_forall(HashTable *ht,

-                    int (*fn)(const HashDatum *key, const HashDatum *val,
+                    int (*fn)(const char *key, HashValue *val,

                               struct ht_forall_ctx *ctx),
                     struct ht_forall_ctx *ctx) {
                               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;
   Tcl_HashSearch sp;
   Tcl_HashEntry *he;

-  HashDatum *key, *val;
+  const char *key;
+  HashValue *val;
+  int r;

   
   for (he= Tcl_FirstHashEntry(&ht->t, &sp);
        he;
   
   for (he= Tcl_FirstHashEntry(&ht->t, &sp);
        he;

-       he= Tcl_NextHashEntry(&ht->t, &sp)) {
+       he= Tcl_NextHashEntry(&sp)) {

     val= Tcl_GetHashValue(he);
     if (!val->len) continue;
 
     val= Tcl_GetHashValue(he);
     if (!val->len) continue;
 


@@ -127,68 +121,85 @@ static int ht_forall(HashTable *ht,
   return 0;
 }
 
   return 0;
 }
 

+static void ht_destroy(HashTable *ht) {
+  Tcl_HashSearch sp;
+  Tcl_HashEntry *he;
+  
+  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 ----------*/
 
 /*---------- Rw data structure ----------*/
 

-typedef struct {
+typedef struct Rw {

   int ix, autocompact;
   int cdb_fd, lock_fd;
   struct cdb cdb; /* valid iff cdb_fd >= 0 */
   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;
   HashTable logincore;
   Pathbuf pbsome, pbother;
   off_t mainsz;
   FILE *logfile;
   HashTable logincore;
   Pathbuf pbsome, pbother;
   off_t mainsz;

+  ScriptToInvoke on_info, on_lexminval;

 } Rw;
 
 } Rw;
 

-static void destroy_cdbrw_idtabcb(Tcl_Interp *ip, void *val) { abort(); }
-
-int rw_close(Interp *ip, Rw *rw) {
+static int rw_close(Tcl_Interp *ip, Rw *rw) {

   int rc, r;
 
   rc= TCL_OK;
   int rc, r;
 
   rc= TCL_OK;

-  ht_destroy(rw);
+  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);
   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);
                                    " fclose logfile during untidy close"); }
   }
 
   pathbuf_free(&rw->pbsome); pathbuf_free(&rw->pbother);

-  TFREE(rw);

   return rc;
   return rc;

-};
-void destroy_cdbrw_idtabcb(Interp *ip, Rw *rw) { rw_close(0,rw); }
+}

 
 

+static void destroy_cdbrw_idtabcb(Tcl_Interp *ip, void *rw) {
+  rw_close(0,rw);
+  TFREE(rw);
+}

 const IdDataSpec cdbtcl_rwdatabases= {
   "cdb-rwdb", "cdb-openrwdatabases-table", destroy_cdbrw_idtabcb
 };
 
 /*---------- File handling ----------*/
 
 const IdDataSpec cdbtcl_rwdatabases= {
   "cdb-rwdb", "cdb-openrwdatabases-table", destroy_cdbrw_idtabcb
 };
 
 /*---------- File handling ----------*/
 

-int acquire_lock(Tcl_Interp *ip, PathBuf *pb, int *lockfd_r) {
+static int acquire_lock(Tcl_Interp *ip, Pathbuf *pb, int *lockfd_r) {

   /* *lockfd_r must be -1 on entry.  If may be set to >=0 even
    * on error, and must be closed by the caller. */
   /* *lockfd_r must be -1 on entry.  If may be set to >=0 even
    * on error, and must be closed by the caller. */

-  mode_t umask, lockmode;
+  mode_t um, lockmode;

   struct flock fl;
   struct flock fl;

+  int r;

 
 

-  umask= umask(~(mode_t)0);
-  umask(umask);
+  um= umask(~(mode_t)0);
+  umask(um);

 
 

-  lockmode= 0666 & ~((umask & 0444)>>1);
+  lockmode= 0666 & ~((um & 0444)>>1);

   /* Remove r where umask would remove w;
    * eg umask intending 0664 here gives 0660 */
   
   /* Remove r where umask would remove w;
    * eg umask intending 0664 here gives 0660 */
   

-  *lockfd_r= open(pathbuf_sfx(".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");
 
   fl.l_type= F_WRLCK;
   fl.l_whence= SEEK_SET;
   fl.l_start= 0;
   if (*lockfd_r < 0)
     return cht_posixerr(ip, errno, "could not open/create lockfile");
 
   fl.l_type= F_WRLCK;
   fl.l_whence= SEEK_SET;
   fl.l_start= 0;

-  fl.l_end= 0;
+  fl.l_len= 0;

   fl.l_pid= getpid();
 
   r= fcntl(*lockfd_r, F_SETLK, &fl);
   fl.l_pid= getpid();
 
   r= fcntl(*lockfd_r, F_SETLK, &fl);


@@ -198,9 +209,11 @@ int acquire_lock(Tcl_Interp *ip, PathBuf *pb, int *lockfd_r) {
     else return cht_posixerr(ip, errno, "unexpected error from fcntl while"
                             " acquiring lock");
   }
     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;
 
 static int readlognum(FILE *f, int delim, int *num_r) {
   int c;


@@ -225,113 +238,211 @@ static int readlognum(FILE *f, int delim, int *num_r) {
 }
 
 static int readstorelogrecord(FILE *f, HashTable *ht,
 }
 
 static int readstorelogrecord(FILE *f, HashTable *ht,

-                             void (*updatefn)(HashTable*, HashDatum*,
-                                              HashDatum*)) {
+                             int (*omitfn)(const HashValue*,
+                                           struct ht_forall_ctx *ctx),
+                             struct ht_forall_ctx *ctx,
+                             void (*updatefn)(HashTable*, const char*,
+                                              HashValue*)) {

   /* returns:
   /* 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;
    */
   int keylen, vallen;

-  HashDatum *key, *val;
+  char *key;
+  HashValue *val;
+  int c, rc, r;

 
   c= getc(f);
 
   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;
 
   rc= readlognum(f, ',', &keylen);  if (rc) return rc;
   rc= readlognum(f, ':', &vallen);  if (rc) return rc;
 
   if (c=='\n') return -3;
   if (c!='+') return -2;
 
   rc= readlognum(f, ',', &keylen);  if (rc) return rc;
   rc= readlognum(f, ':', &vallen);  if (rc) return rc;
 

-  key= htd_prep(keylen);
-  val= htd_prep(vallen);
+  key= TALLOC(keylen+1);
+  val= htv_prep(vallen);

 
 

-  r= fread(htd_fillptr(key), 1,keylen, f);
+  r= fread(key, 1,keylen, f);

   if (r!=keylen) goto x2_free_keyval;
   if (r!=keylen) goto x2_free_keyval;

+  if (memchr(key,0,keylen)) goto x2_free_keyval;
+  key[keylen]= 0;

 
   c= getc(f);  if (c!='-') goto x2_free_keyval;
   c= getc(f);  if (c!='>') goto x2_free_keyval;
   
 
   c= getc(f);  if (c!='-') goto x2_free_keyval;
   c= getc(f);  if (c!='>') goto x2_free_keyval;
   

-  r= fread(htd_fillptr(val), 1,vallen, f);
+  r= fread(htv_fillptr(val), 1,vallen, f);

   if (r!=vallen) goto x2_free_keyval;
 
   if (r!=vallen) goto x2_free_keyval;
 

-  updatefn(ht, key, val);
-  return TCL_OK;
+  c= getc(f);  if (c!='\n') goto x2_free_keyval;

 
 

-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 rc;
+
+ x2_free_keyval:

   TFREE(val);
   TFREE(key);
   return -2;
 }
 
   TFREE(val);
   TFREE(key);
   return -2;
 }
 

+static int writerecord(FILE *f, const char *key, const HashValue *val) {
+  int r;
+
+  r= fprintf(f, "+%d,%d:%s->", 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) {
 /*---------- 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", ".log", ".tmp", 0 };

 
 

-  Pathbuf pb;
-  int lock_fd=-1, fd=-1, rc;
+  Pathbuf pb, pbmain;
+  int lock_fd=-1, rc, r;
+  FILE *f= 0;

   const char *const *toremove;
   const char *const *toremove;

+  struct stat stab;

 
   pathbuf_init(&pb, pathb);
 
   pathbuf_init(&pb, pathb);

+  pathbuf_init(&pbmain, pathb);
+

   rc= acquire_lock(ip, &pb, &lock_fd);  if (rc) goto x_rc;
   rc= acquire_lock(ip, &pb, &lock_fd);  if (rc) goto x_rc;

-  
-  fd= open(pathbuf_sfx(".main"), O_RDWR|O_CREAT|O_EXCL, 0666);
-  if (fd <= 0) PE("create new database file");

 
 

-  for (toremoves=toremove; *toremove; toremove++) {
-    r= remove(*toremove);
+  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(pathbuf_sfx(&pb, *toremove));

     if (r && errno != ENOENT)
       PE("delete possible spurious file during creation");
   }
   
     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:
   rc= TCL_OK;
 
  x_rc:

-  maybe_close(fd);
+  if (f) fclose(f);

   maybe_close(lock_fd);
   pathbuf_free(&pb);
   maybe_close(lock_fd);
   pathbuf_free(&pb);

+  pathbuf_free(&pbmain);

   return rc;
 }
 
   return rc;
 }
 

+/*---------- Info callbacks ----------*/
+
+static int infocbv3(Tcl_Interp *ip, Rw *rw, const char *arg1,
+                   const char *arg2fmt, const char *arg3, va_list al) {
+  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,
+                  const char *arg2fmt, const char *arg3, ...) {
+  int rc;
+  va_list al;
+  va_start(al, arg3);
+  rc= infocbv3(ip,rw,arg1,arg2fmt,arg3,al);
+  va_end(al);
+  return rc;
+}
+  
+static int infocb(Tcl_Interp *ip, Rw *rw, const char *arg1,
+                 const char *arg2fmt, ...) {
+  int rc;
+  va_list al;
+  va_start(al, arg2fmt);
+  rc= infocbv3(ip,rw,arg1,arg2fmt,0,al);
+  va_end(al);
+  return rc;
+}
+  

 /*---------- Opening ----------*/
 
 /*---------- Opening ----------*/
 

-int cht_do_cdbwr_open(ClientData cd, Tcl_Interp *ip,
-                     const char *pathb, Tcl_Obj *on_info, void **result) {
+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, Tcl_Obj *on_lexminval,
+                     void **result) {

   const Cdbwr_SubCommand *subcmd= cd;
   const Cdbwr_SubCommand *subcmd= cd;

-  int rc, mainfd=-1;
+  int r, rc, mainfd=-1;

   Rw *rw;
   struct stat stab;
   Rw *rw;
   struct stat stab;

-  fpos_t logrecstart;
+  off_t logrecstart, logjunkpos;

 
   rw= TALLOC(sizeof(*rw));
 
   rw= TALLOC(sizeof(*rw));

-  rc= ht_setup(&rw->logincore);  if (rc) { TFREE(rw); return rc; }
+  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->cdb_fd= rw->lock_fd= -1;  rw->logfile= 0;

-  pathbuf_init(&rw->pbsome, &pathb);
-  pathbuf_init(&rw->pbother, &pathb);
+  pathbuf_init(&rw->pbsome, pathb);
+  pathbuf_init(&rw->pbother, pathb);

   rw->autocompact= 1;
 
   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);
   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;
 
   rc= acquire_lock(ip, &rw->pbsome, &rw->lock_fd);  if (rc) goto x_rc;
 

-  r= stat(mainfd, &stab);  if (r) PE("fstat .main");
+  r= fstat(mainfd, &stab);  if (r) PE("fstat .main");

   rw->mainsz= stab.st_size;
 
   rw->cdb_fd= open(pathbuf_sfx(&rw->pbsome,".cdb"), O_RDONLY);
   rw->mainsz= stab.st_size;
 
   rw->cdb_fd= open(pathbuf_sfx(&rw->pbsome,".cdb"), O_RDONLY);

-  if (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;
-    }
+  if (rw->cdb_fd >=0) {
+    rc= cdbinit(ip, rw);  if (rc) goto x_rc;

   } else if (errno == ENOENT) {
   } 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;
                        " .cdb must have been accidentally deleted!",
                        "CDB CDBMISSING");
       goto x_rc;


@@ -349,14 +460,14 @@ int cht_do_cdbwr_open(ClientData cd, Tcl_Interp *ip,
   } else { /* rw->logfile */
     r= fstat(fileno(rw->logfile), &stab);
     if (r==-1) PE("fstat .log during open");
   } else { /* rw->logfile */
     r= fstat(fileno(rw->logfile), &stab);
     if (r==-1) PE("fstat .log during open");

-    rc= infocb(rw, "open-dirty-start", "log=%luby",
+    rc= infocb(ip, rw, "open-dirty-start", "log=%luby",

               (unsigned long)stab.st_size);
     if (rc) goto x_rc;
 
     for (;;) {
               (unsigned long)stab.st_size);
     if (rc) goto x_rc;
 
     for (;;) {

-      r= fgetpos(rw->logfile, &logrecstart);
-      if (r) PE("fgetpos .log during (dirty) open");
-      r= readstorelogrecord(rw->logfile, &rw->logincore, ht_update);
+      logrecstart= ftello(rw->logfile);
+      if (logrecstart < 0) PE("ftello .log 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");
        goto x_rc;
       if (ferror(rw->logfile)) {
        rc= cht_posixerr(ip, errno, "error reading .log during (dirty) open");
        goto x_rc;


@@ -365,27 +476,27 @@ int cht_do_cdbwr_open(ClientData cd, Tcl_Interp *ip,
        break;
       } else if (r==-2 || r==-3) {
        char buf[100];
        break;
       } else if (r==-2 || r==-3) {
        char buf[100];

-       r= fgetpos(rw->logfile, &logjunkpos);
-       if (r) PE("fgetpos .log during report of junk in dirty open");
+       logjunkpos= ftello(rw->logfile);
+       if(logjunkpos<0) PE("ftello .log during report of junk in dirty open");

 
        snprintf(buf,sizeof(buf), "CDB SYNTAX LOG %lu %lu",
 
        snprintf(buf,sizeof(buf), "CDB SYNTAX LOG %lu %lu",

-                (unsigned long)junkpos, (unsigned long)logrecstart);
+                (unsigned long)logjunkpos, (unsigned long)logrecstart);

 
        if (!(subcmd->flags & RWSCF_OKJUNK)) {
          Tcl_SetObjErrorCode(ip, Tcl_NewStringObj(buf,-1));
 
        if (!(subcmd->flags & RWSCF_OKJUNK)) {
          Tcl_SetObjErrorCode(ip, Tcl_NewStringObj(buf,-1));

-         snprintf(buf,sizeof(buf),"%lu",(unsigned long)junkpos);
+         snprintf(buf,sizeof(buf),"%lu",(unsigned long)logjunkpos);

          Tcl_ResetResult(ip);
          Tcl_AppendResult(ip, "syntax error (junk) in .log during"
                           " (dirty) open, at file position ", buf, (char*)0);
          rc= TCL_ERROR;
          goto x_rc;
        }
          Tcl_ResetResult(ip);
          Tcl_AppendResult(ip, "syntax error (junk) in .log during"
                           " (dirty) open, at file position ", buf, (char*)0);
          rc= TCL_ERROR;
          goto x_rc;
        }

-       rc= infocb(rw, "open-dirty-junk", "errorfpos=%luby {%s}",
-                  (unsigned long)logjunkpos, buf);
+       rc= infocb3(ip, rw, "open-dirty-junk", "errorfpos=%luby", buf,
+                   (unsigned long)logjunkpos);

        if (rc) goto x_rc;
 
        if (rc) goto x_rc;
 

-       r= fsetpos(rw->logfile, logrecstart);
-       if (r) PE("failed to fsetpos .log before junk during dirty open");
+       r= fseeko(rw->logfile, logrecstart, SEEK_SET);
+       if (r) PE("failed to fseeko .log before junk during dirty open");

 
        r= ftruncate(fileno(rw->logfile), logrecstart);
        if (r) PE("ftruncate .log to chop junk during dirty open");
 
        r= ftruncate(fileno(rw->logfile), logrecstart);
        if (r) PE("ftruncate .log to chop junk during dirty open");


@@ -402,61 +513,135 @@ int cht_do_cdbwr_open(ClientData cd, Tcl_Interp *ip,
 
  x_rc:
   rw_close(0,rw);
 
  x_rc:
   rw_close(0,rw);

+  TFREE(rw);

   maybe_close(mainfd);
   return rc;
 }
 
   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 */
+};
+
+/*---------- helper functions ----------*/

 
 

-static int compact_core(Tcl_Interp *ip, Rw *rw, unsigned long logsz) {
+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 cdb fd open onto old db
    * leaves logincore full of crap
    */
   /* creates new .cdb and .main
    * closes logfile
    * leaves .log with old data
    * leaves cdb fd open onto old db
    * leaves logincore full of crap
    */

-  int rc;
+  int r, rc;

   int cdbfd, cdbmaking;
   int cdbfd, cdbmaking;

-  struct ht_forall_ctx {
-    struct cdb_make cdbm;
-    FILE *mainfile;
-    int count;
-  } addctx;
+  off_t errpos, newmainsz;
+  char buf[100];
+  Tcl_Obj *res;
+  struct ht_forall_ctx a;

 
   a.mainfile= 0;
   cdbfd= -1;
   cdbmaking= 0;
 
   a.mainfile= 0;
   cdbfd= -1;
   cdbmaking= 0;

+  *reccount_r= 0;
+  a.reccount= reccount_r;

 
   r= fclose(rw->logfile);
 
   r= fclose(rw->logfile);

-  if (r) { rc= cht_posixerr(ip, errno, "data loss!  failed to fclose"
+  if (r) { rc= cht_posixerr(ip, errno, "probable data loss!  failed to fclose"

                            " logfile during compact");  goto x_rc; }
   rw->logfile= 0;
   
   rc= infocb(ip, rw, "compact-start", "log=%luby main=%luby",
                            " logfile during compact");  goto x_rc; }
   rw->logfile= 0;
   
   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 (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 */
 
   /* merge unsuperseded records from main into hash table */
 

-  a.mainfile= fopen(pathbuf_sfx(&rw_pbsome,".main"), "r");
+  a.mainfile= fopen(pathbuf_sfx(&rw->pbsome,".main"), "r");

   if (!a.mainfile) PE("failed to open .main for reading during compact");
 
   for (;;) {
   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"
     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) {
     if (r==-3) {
       break;
     } else if (r==-1 || r==-2) {

-      r= fgetpos(a.mainfile, &errpos);
-      if (r) PE("fgetpos .main during report of syntax error");
-      snprintf(buf,sizeof(buf), "CDB SYNTAX MAIN %lu", (uunsigned long)errpos);
+      errpos= ftello(a.mainfile);
+      if (errpos<0) PE("ftello .main during report of syntax error");
+      snprintf(buf,sizeof(buf), "CDB %s MAIN %lu",
+              r==-1 ? "TRUNCATED" : "SYNTAX", (unsigned long)errpos);

       Tcl_SetObjErrorCode(ip, Tcl_NewStringObj(buf,-1));
       Tcl_SetObjErrorCode(ip, Tcl_NewStringObj(buf,-1));

-      snprintf(buf,sizeof(buf), "%lu", (uunsigned long)errpos);
+      snprintf(buf,sizeof(buf), "%lu", (unsigned long)errpos);

       Tcl_ResetResult(ip);
       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 {
       rc= TCL_ERROR;
       goto x_rc;
     } else {


@@ -475,10 +660,10 @@ static int compact_core(Tcl_Interp *ip, Rw *rw, unsigned long logsz) {
   if (r) PE("cdb_make_start during compact");
   cdbmaking= 1;
 
   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");
 
   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;
 
   if(r) PE("cdb_make_finish during compact");
   cdbmaking= 0;
 


@@ -494,14 +679,19 @@ static int compact_core(Tcl_Interp *ip, Rw *rw, unsigned long logsz) {
   a.mainfile= fopen(pathbuf_sfx(&rw->pbsome,".tmp"), "w");
   if (!a.mainfile) PE("create .tmp for new main during compact");
 
   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);
+  r= ht_forall(&rw->logincore, addto_main, &a);

   if (r) { rc= cht_posixerr(ip, r, "error writing to new .main"
                            " during compact");  goto x_rc; }
   if (r) { rc= cht_posixerr(ip, r, "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");
   
   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;
   
   r= fclose(a.mainfile);  if (r) PE("fclose new main during compact");
   a.mainfile= 0;


@@ -509,53 +699,226 @@ static int compact_core(Tcl_Interp *ip, Rw *rw, unsigned long logsz) {
   r= rename(rw->pbsome.buf, pathbuf_sfx(&rw->pbother,".main"));
   if (r) PE("install new .main during compact");
 
   r= rename(rw->pbsome.buf, pathbuf_sfx(&rw->pbother,".main"));
   if (r) PE("install new .main during compact");
 

+  rw->mainsz= newmainsz;
+

   /* done! */
   
   /* 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;
 
   if (rc) goto x_rc;
 

-  rc= TCL_OK;
+  return rc;
+

 x_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 */
   maybe_close(cdbfd);
   remove(pathbuf_sfx(&rw->pbsome,".tmp")); /* for tidyness */

+  return rc;

 }
 }

-  
-static void compact_forclose(Tcl_Interp *ip, Rw *rw) {
-  long logsz;
-  int rc;

 
 

-  logsz= ftell(rw->logfile);
-  if (logsz < 0) PE("ftell logfile (during tidy close)");
+/*---------- Closing ----------*/
+
+static int compact_forclose(Tcl_Interp *ip, Rw *rw, long *reccount_r) {
+  off_t logsz;
+  int r, rc;

 
 

-  rc= compact_core(ip, rw, logsz);  if (rc) goto x_rc;
+  logsz= ftello(rw->logfile);
+  if (logsz < 0) PE("ftello logfile (during tidy close)");
+
+  rc= compact_core(ip, rw, logsz, reccount_r);  if (rc) goto x_rc;

 
   r= remove(pathbuf_sfx(&rw->pbsome,".log"));
   if (r) PE("remove .log (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 cht_do_cdbwr_close(ClientData cd, Tcl_Interp *ip, void *rw_v) {
   Rw *rw= rw_v;

-  int rc, compact_rc, infocb_rc;
+  int rc, rc_close;
+  long reccount= -1;
+  off_t logsz;
+
+  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=%l", 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);
+  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 .log"
+                                      " 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,".log"), "w");
+  if (!rw->logfile) PE("reopen .log after compact");
+
+  r= fsync(fileno(rw->logfile));  if (r) PE("fsync .log 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 ----------*/

 
 

-  if (rw->autocompact) compact_rc= compact_forclose(ip, rw);
-  else compact_rc= TCL_OK;
+static int update(Tcl_Interp *ip, Rw *rw, const char *key,
+                 const Byte *data, int dlen) {
+  HashValue *val;
+  int rc, r;

 
 

-  rc= rw_close(ip,rw);
-  infocb_rc= infocb_close(rw);
+  if (!rw->logfile) return cht_staticerr
+    (ip, "previous compact failed; cdbwr must be closed and reopened "
+     "before any further updates", "CDB BROKEN");

   
   

-  cht_tabledataid_disposing(ip, rw_v, &cdbtcl_rwdatabases);
-  if (!rc) rc= compact_rc;
-  if (!rc) rc= infocb_rc;
+  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);

   return rc;
   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;

   
   

-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);
+  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_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);
+}
+
+int cht_do_cdbtoplevel_cdb_wr(ClientData cd, Tcl_Interp *ip,
+                             const Cdbwr_SubCommand* subcmd,
+                             int objc, Tcl_Obj *const *objv) {
+  return subcmd->func((void*)subcmd,ip,objc,objv);
+}