Update the SECURE_DELETE code to track the latest changes in the pager. (CVS 5928)

FossilOrigin-Name: e058f509374e98e48eafeba2f1dadff9633d1190
2025-08-07 02:42:48 +03:00 · 2008-11-19 18:30:29 +00:00
parent f3d3c27a0c
commit 1feb7dd391
5 changed files with 113 additions and 64 deletions
--- a/18
+++ b/18
@@ -1,5 +1,5 @@
-C Fix\ssome\scompiler\swarnings\sthat\sshow\sup\swhen\sbuilding\sthe\samalgamation\sonly.\s(CVS\s5927)
-D 2008-11-19T16:52:44
+C Update\sthe\sSECURE_DELETE\scode\sto\strack\sthe\slatest\schanges\sin\sthe\spager.\s(CVS\s5928)
+D 2008-11-19T18:30:29
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 0aa7bbe3be6acc4045706e3bb3fd0b8f38f4a3b5
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -98,7 +98,7 @@ F src/alter.c 0a00c184052b7fd20271e783f65fec4efec6fe30
 F src/analyze.c 301a1358f4f4d84d96608927d8ddcf471c53ad9a
 F src/attach.c 85c6a3d0daf11965b47604190d7cf5597dc88382
 F src/auth.c c8b2ab5c8bad4bd90ed7c294694f48269162c627
-F src/bitvec.c 9e922b2577b7e46d8f95349bca6a52f7674d7582
+F src/bitvec.c 4300d311b17fb3c1476623fd895a8feac02a0b08
 F src/btmutex.c 63c5cc4ad5715690767ffcb741e185d7bc35ec1a
 F src/btree.c 76c1b09263b6f028b4f84bd6d811e9d017448216
 F src/btree.h 179c3ea813780df78a289a8f5130db18e6d4616e
@@ -139,7 +139,7 @@ F src/os_common.h 24525d8b7bce66c374dfc1810a6c9043f3359b60
 F src/os_os2.c d12285d66df674c42f6f544a6f7c21bf1a954ee1
 F src/os_unix.c 03c76b5269361adcd68cf9d6713181922535ac6e
 F src/os_win.c 08d0b059ac01f32e8813bb96fc573486592b83f5
-F src/pager.c ae5da38b6415bdd88e56a2a484f29282c4ea09f5
+F src/pager.c db12a8333e54e7bbf62dc621ada5507adb3a6493
 F src/pager.h a02ef8e6cc7e78b54874166e5ce786c9d4c489bf
 F src/parse.y 2c4758b4c5ead6de8cf7112f5a7cce7561d313fe
 F src/pcache.c f3121a531745b20f5b824201eb63949a7e2959ac
@@ -233,7 +233,7 @@ F test/bigfile.test 9a6a8346e4042d9c781ed6cb6553ac871ae30618
 F test/bigrow.test f0aeb7573dcb8caaafea76454be3ade29b7fc747
 F test/bind.test 1134441f1ea47abd1c740090435a6ecbe9ceb263
 F test/bindxfer.test d4f573750e06c34ef2309acb95ad57da1d3c983f
-F test/bitvec.test 62a512c3f7041d1df12558eb25990e5a19820571
+F test/bitvec.test ecea9aa315f36991e56e326701279b7775cb2bef
 F test/blob.test 2a38d867bdf08f9ce081776acec1ac8d4bca66be
 F test/busy.test 76b4887f8b9160ba903c1ac22e8ff406ad6ae2f0
 F test/cache.test 3ff445c445742a7b6b9ba6e1d62a25263f9424b9
@@ -659,7 +659,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 70b2f6839ca97dfc08f72875283f5c75c8fcf0cc
-R a6290aee52476a40993da5bd0918f0b1
-U danielk1977
-Z dc69f77ff700b57401f380f9e520f0dd
+P d1abe8a1c9a990b02c71d6c249436381c9fde443
+R 28c8816dfcd8d3fc398d31f18c45452f
+U drh
+Z e8976cc9cb4c6c0e128dc1d970073d42
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-d1abe8a1c9a990b02c71d6c249436381c9fde443
+e058f509374e98e48eafeba2f1dadff9633d1190
--- a/src/bitvec.c
+++ b/src/bitvec.c
@@ -34,21 +34,42 @@
 ** start of a transaction, and is thus usually less than a few thousand,
 ** but can be as large as 2 billion for a really big database.
 **
-** @(#) $Id: bitvec.c,v 1.8 2008/11/11 15:48:48 drh Exp $
+** @(#) $Id: bitvec.c,v 1.9 2008/11/19 18:30:35 shane Exp $
 */
 #include "sqliteInt.h"

+/* Size of the Bitvec structure in bytes. */
 #define BITVEC_SZ        512
+
 /* Round the union size down to the nearest pointer boundary, since that's how 
 ** it will be aligned within the Bitvec struct. */
-#define BITVEC_USIZE     (((BITVEC_SZ-12)/sizeof(Bitvec*))*sizeof(Bitvec*))
-#define BITVEC_NCHAR     BITVEC_USIZE
-#define BITVEC_NBIT      (BITVEC_NCHAR*8)
-#define BITVEC_NINT      (BITVEC_USIZE/4)
+#define BITVEC_USIZE     (((BITVEC_SZ-(3*sizeof(u32)))/sizeof(Bitvec*))*sizeof(Bitvec*))
+
+/* Type of the array "element" for the bitmap representation. 
+** Should be a power of 2, and ideally, evenly divide into BITVEC_USIZE. 
+** Setting this to the "natural word" size of your CPU may improve
+** performance. */
+#define BITVEC_TELEM     u8
+/* Size, in bits, of the bitmap element. */
+#define BITVEC_SZELEM    8
+/* Number of elements in a bitmap array. */
+#define BITVEC_NELEM     (BITVEC_USIZE/sizeof(BITVEC_TELEM))
+/* Number of bits in the bitmap array. */
+#define BITVEC_NBIT      (BITVEC_NELEM*BITVEC_SZELEM)
+
+/* Number of u32 values in hash table. */
+#define BITVEC_NINT      (BITVEC_USIZE/sizeof(u32))
+/* Maximum number of entries in hash table before 
+** sub-dividing and re-hashing. */
 #define BITVEC_MXHASH    (BITVEC_NINT/2)
+/* Hashing function for the aHash representation.
+** Empirical testing showed that the *37 multiplier 
+** (an arbitrary prime)in the hash function provided 
+** no fewer collisions than the no-op *1. */
+#define BITVEC_HASH(X)   (((X)*1)%BITVEC_NINT)
+
 #define BITVEC_NPTR      (BITVEC_USIZE/sizeof(Bitvec *))

-#define BITVEC_HASH(X)   (((X)*37)%BITVEC_NINT)

 /*
 ** A bitmap is an instance of the following structure.
@@ -72,11 +93,15 @@
 ** to hold deal with values between 1 and iDivisor.
 */
 struct Bitvec {
-  u32 iSize;      /* Maximum bit index */
-  u32 nSet;       /* Number of bits that are set */
-  u32 iDivisor;   /* Number of bits handled by each apSub[] entry */
+  u32 iSize;      /* Maximum bit index.  Max iSize is 4,294,967,296. */
+  u32 nSet;       /* Number of bits that are set - only valid for aHash element */
+                  /* Max nSet is BITVEC_NINT.  For BITVEC_SZ of 512, this would be 125. */
+  u32 iDivisor;   /* Number of bits handled by each apSub[] entry. */
+                  /* Should >=0 for apSub element. */
+                  /* Max iDivisor is max(u32) / BITVEC_NPTR + 1.  */
+                  /* For a BITVEC_SZ of 512, this would be 34,359,739. */
  union {
-    u8 aBitmap[BITVEC_NCHAR];    /* Bitmap representation */
+    BITVEC_TELEM aBitmap[BITVEC_NELEM];    /* Bitmap representation */
    u32 aHash[BITVEC_NINT];      /* Hash table representation */
    Bitvec *apSub[BITVEC_NPTR];  /* Recursive representation */
  } u;
@@ -105,16 +130,19 @@ Bitvec *sqlite3BitvecCreate(u32 iSize){
 int sqlite3BitvecTest(Bitvec *p, u32 i){
  if( p==0 ) return 0;
  if( i>p->iSize || i==0 ) return 0;
-  if( p->iSize<=BITVEC_NBIT ){
  i--;
-    return (p->u.aBitmap[i/8] & (1<<(i&7)))!=0;
+  while( p->iDivisor ){
+    u32 bin = i/p->iDivisor;
+    i = i%p->iDivisor;
+    p = p->u.apSub[bin];
+    if (!p) {
+      return 0;
    }
-  if( p->iDivisor>0 ){
-    u32 bin = (i-1)/p->iDivisor;
-    i = (i-1)%p->iDivisor + 1;
-    return sqlite3BitvecTest(p->u.apSub[bin], i);
-  }else{
-    u32 h = BITVEC_HASH(i);
+  }
+  if( p->iSize<=BITVEC_NBIT ){
+    return (p->u.aBitmap[i/BITVEC_SZELEM] & (1<<(i&(BITVEC_SZELEM-1))))!=0;
+  } else{
+    u32 h = BITVEC_HASH(i++);
    while( p->u.aHash[h] ){
      if( p->u.aHash[h]==i ) return 1;
      h++;
@@ -141,35 +169,50 @@ int sqlite3BitvecSet(Bitvec *p, u32 i){
  assert( p!=0 );
  assert( i>0 );
  assert( i<=p->iSize );
-  if( p->iSize<=BITVEC_NBIT ){
  i--;
-    p->u.aBitmap[i/8] |= 1 << (i&7);
-    return SQLITE_OK;
-  }
-  if( p->iDivisor ){
-    u32 bin = (i-1)/p->iDivisor;
-    i = (i-1)%p->iDivisor + 1;
+  while((p->iSize > BITVEC_NBIT) && p->iDivisor) {
+    u32 bin = i/p->iDivisor;
+    i = i%p->iDivisor;
    if( p->u.apSub[bin]==0 ){
      sqlite3BeginBenignMalloc();
      p->u.apSub[bin] = sqlite3BitvecCreate( p->iDivisor );
      sqlite3EndBenignMalloc();
      if( p->u.apSub[bin]==0 ) return SQLITE_NOMEM;
    }
-    return sqlite3BitvecSet(p->u.apSub[bin], i);
+    p = p->u.apSub[bin];
  }
-  h = BITVEC_HASH(i);
-  while( p->u.aHash[h] ){
+  if( p->iSize<=BITVEC_NBIT ){
+    p->u.aBitmap[i/BITVEC_SZELEM] |= 1 << (i&(BITVEC_SZELEM-1));
+    return SQLITE_OK;
+  }
+  h = BITVEC_HASH(i++);
+  /* if there wasn't a hash collision, and this doesn't */
+  /* completely fill the hash, then just add it without */
+  /* worring about sub-dividing and re-hashing. */
+  if( !p->u.aHash[h] ){
+    if (p->nSet<(BITVEC_NINT-1)) {
+      goto bitvec_set_end;
+    } else {
+      goto bitvec_set_rehash;
+    }
+  }
+  /* there was a collision, check to see if it's already */
+  /* in hash, if not, try to find a spot for it */
+  do {
    if( p->u.aHash[h]==i ) return SQLITE_OK;
    h++;
-    if( h==BITVEC_NINT ) h = 0;
-  }
-  p->nSet++;
+    if( h>=BITVEC_NINT ) h = 0;
+  } while( p->u.aHash[h] );
+  /* we didn't find it in the hash.  h points to the first */
+  /* available free spot. check to see if this is going to */
+  /* make our hash too "full".  */
+bitvec_set_rehash:
  if( p->nSet>=BITVEC_MXHASH ){
    unsigned int j;
    int rc;
    u32 aiValues[BITVEC_NINT];
    memcpy(aiValues, p->u.aHash, sizeof(aiValues));
-    memset(p->u.apSub, 0, sizeof(p->u.apSub[0])*BITVEC_NPTR);
+    memset(p->u.apSub, 0, sizeof(aiValues));
    p->iDivisor = (p->iSize + BITVEC_NPTR - 1)/BITVEC_NPTR;
    rc = sqlite3BitvecSet(p, i);
    for(j=0; j<BITVEC_NINT; j++){
@@ -177,35 +220,44 @@ int sqlite3BitvecSet(Bitvec *p, u32 i){
    }
    return rc;
  }
+bitvec_set_end:
+  p->nSet++;
  p->u.aHash[h] = i;
  return SQLITE_OK;
 }

 /*
-** Clear the i-th bit.  Return 0 on success and an error code if
-** anything goes wrong.
+** Clear the i-th bit.
 */
 void sqlite3BitvecClear(Bitvec *p, u32 i){
  assert( p!=0 );
  assert( i>0 );
-  if( p->iSize<=BITVEC_NBIT ){
  i--;
-    p->u.aBitmap[i/8] &= ~(1 << (i&7));
-  }else if( p->iDivisor ){
-    u32 bin = (i-1)/p->iDivisor;
-    i = (i-1)%p->iDivisor + 1;
-    if( p->u.apSub[bin] ){
-      sqlite3BitvecClear(p->u.apSub[bin], i);
+  while( p->iDivisor ){
+    u32 bin = i/p->iDivisor;
+    i = i%p->iDivisor;
+    p = p->u.apSub[bin];
+    if (!p) {
+      return;
    }
+  }
+  if( p->iSize<=BITVEC_NBIT ){
+    p->u.aBitmap[i/BITVEC_SZELEM] &= ~(1 << (i&(BITVEC_SZELEM-1)));
  }else{
    unsigned int j;
    u32 aiValues[BITVEC_NINT];
    memcpy(aiValues, p->u.aHash, sizeof(aiValues));
-    memset(p->u.aHash, 0, sizeof(p->u.aHash[0])*BITVEC_NINT);
+    memset(p->u.aHash, 0, sizeof(aiValues));
    p->nSet = 0;
    for(j=0; j<BITVEC_NINT; j++){
-      if( aiValues[j] && aiValues[j]!=i ){
-        sqlite3BitvecSet(p, aiValues[j]);
+      if( aiValues[j] && aiValues[j]!=(i+1) ){
+        u32 h = BITVEC_HASH(aiValues[j]-1);
+        p->nSet++;
+        while( p->u.aHash[h] ){
+          h++;
+          if( h>=BITVEC_NINT ) h = 0;
+        }
+        p->u.aHash[h] = aiValues[j];
      }
    }
  }
--- a/src/pager.c
+++ b/src/pager.c
@@ -18,7 +18,7 @@
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
 **
-** @(#) $Id: pager.c,v 1.505 2008/11/19 10:22:33 danielk1977 Exp $
+** @(#) $Id: pager.c,v 1.506 2008/11/19 18:30:29 drh Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 #include "sqliteInt.h"
@@ -3488,7 +3488,8 @@ void sqlite3PagerDontRollback(DbPage *pPg){
  }

 #ifdef SQLITE_SECURE_DELETE
-  if( (pPg->flags & PGHDR_IN_JOURNAL)!=0 || pPg->pgno>pPager->origDbSize ){
+  if( sqlite3BitvecTest(pPager->pInJournal, pPg->pgno)!=0
+   || pPg->pgno>pPager->origDbSize ){
    return;
  }
 #endif
--- a/test/bitvec.test
+++ b/test/bitvec.test
@@ -11,7 +11,7 @@
 #
 # Unit testing of the Bitvec object.
 #
-# $Id: bitvec.test,v 1.2 2008/03/21 16:45:48 drh Exp $
+# $Id: bitvec.test,v 1.3 2008/11/19 18:30:35 shane Exp $
 #

 set testdir [file dirname $argv0]
@@ -185,7 +185,3 @@ for {set n 1} {$go} {incr n} {

 finish_test
 return
-
-
-
-finish_test