From: danielk1977 <danielk1977@noemail.net>
Date: Wed, 1 Apr 2009 19:07:03 +0000 (+0000)
Subject: Remove an unreachable branch from lockBtree(). Add comments. (CVS 6428)
X-Git-Tag: version-3.6.15~322
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=295dc10573784659acaf709fdddaf53b0e6798bc;p=thirdparty%2Fsqlite.git

Remove an unreachable branch from lockBtree(). Add comments. (CVS 6428)

FossilOrigin-Name: 859792958b4d4a3623d68526ff773f778bdf3f0d
---

diff --git a/manifest b/manifest
index 6832a0b272..5152717dc3 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sa\sbug\sin\sthe\ssqlite3Utf16ByteLen()\sfunction\sso\sthat\sit\scomputes\sthe\ncorrect\slength\seven\sfor\sstrings\sthat\scontain\ssurrogate\spairs.\nTicket\s#3766.\s(CVS\s6427)
-D 2009-04-01T18:40:32
+C Remove\san\sunreachable\sbranch\sfrom\slockBtree().\sAdd\scomments.\s(CVS\s6428)
+D 2009-04-01T19:07:04
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in 583e87706abc3026960ed759aff6371faf84c211
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -103,7 +103,7 @@ F src/auth.c c8b2ab5c8bad4bd90ed7c294694f48269162c627
 F src/backup.c 0082d0e5a63f04e88faee0dff0a7d63d3e92a78d
 F src/bitvec.c 44f7059ac1f874d364b34af31b9617e52223ba75
 F src/btmutex.c 341502bc496dc0840dcb00cde65680fb0e85c3ab
-F src/btree.c 3e831426631f0eff0b56d7980ba39cfc53911727
+F src/btree.c dcf8157bd4b28a6125d2900f3031a034c1f57720
 F src/btree.h e302c5747494067cd4f5763000fbe7bca767d816
 F src/btreeInt.h df64030d632f8c8ac217ed52e8b6b3eacacb33a5
 F src/build.c 72357fd75ef036d0afbf1756edab6d62c56fcf4b
@@ -714,7 +714,7 @@ F tool/speedtest16.c c8a9c793df96db7e4933f0852abb7a03d48f2e81
 F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
-P 3a92c95644ead7c4728ffec1ec70676663518188
-R a8645e4c19e0d7546ed7b3fc51d85afa
-U drh
-Z f7ca868d3c85446b0badce3658c2c808
+P 766bb7e59c28884e40ce13e3fc55c870d06d7e34
+R 3a6094ea8b9dd0c5d4c7f018f1b56432
+U danielk1977
+Z 51aefb40d1f48fec12c4fcbcd1a2197b
diff --git a/manifest.uuid b/manifest.uuid
index 4e6aa45b32..164ad3198d 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-766bb7e59c28884e40ce13e3fc55c870d06d7e34
\ No newline at end of file
+859792958b4d4a3623d68526ff773f778bdf3f0d
\ No newline at end of file
diff --git a/src/btree.c b/src/btree.c
index d012bbc70b..69264f42aa 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -9,7 +9,7 @@
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
-** $Id: btree.c,v 1.586 2009/04/01 18:03:01 danielk1977 Exp $
+** $Id: btree.c,v 1.587 2009/04/01 19:07:04 danielk1977 Exp $
 **
 ** This file implements a external (disk-based) database using BTrees.
 ** See the header comment on "btreeInt.h" for additional information.
@@ -1886,7 +1886,7 @@ static int lockBtree(BtShared *pBt){
   int nPage;
 
   assert( sqlite3_mutex_held(pBt->mutex) );
-  if( pBt->pPage1 ) return SQLITE_OK;
+  assert( pBt->pPage1==0 );
   rc = sqlite3BtreeGetPage(pBt, 1, &pPage1, 0);
   if( rc!=SQLITE_OK ) return rc;
 
@@ -2155,11 +2155,14 @@ int sqlite3BtreeBeginTrans(Btree *p, int wrflag){
 #endif
 
   do {
-    if( pBt->pPage1==0 ){
-      do{
-        rc = lockBtree(pBt);
-      }while( pBt->pPage1==0 && rc==SQLITE_OK );
-    }
+    /* Call lockBtree() until either pBt->pPage1 is populated or
+    ** lockBtree() returns something other than SQLITE_OK. lockBtree()
+    ** may return SQLITE_OK but leave pBt->pPage1 set to 0 if after
+    ** reading page 1 it discovers that the page-size of the database 
+    ** file is not pBt->pageSize. In this case lockBtree() will update
+    ** pBt->pageSize to the page-size of the file on disk.
+    */
+    while( pBt->pPage1==0 && SQLITE_OK==(rc = lockBtree(pBt)) );
 
     if( rc==SQLITE_OK && wrflag ){
       if( pBt->readOnly ){