From a55e93555ea9db69971869f8fb719b2ca793c00e Mon Sep 17 00:00:00 2001
From: danielk1977 <danielk1977@noemail.net>
Date: Mon, 21 Jan 2008 13:04:34 +0000
Subject: [PATCH] Remove some unused branches from internal function
 sqlite3PagerDontRollback(). (CVS 4733)

FossilOrigin-Name: 3d4252b06b42151874ee437c3a484e818232a5c9
---
 manifest      | 14 ++++++-------
 manifest.uuid |  2 +-
 src/pager.c   | 55 ++++++++++++++++++++++++++++++++-------------------
 3 files changed, 43 insertions(+), 28 deletions(-)

diff --git a/manifest b/manifest
index 8b5d42a618..fdc489ca90 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\sthe\sRTRIM\scollating\ssequence.\s\sOnly\simplemented\sfor\sUTF8.\s\sStill\nconsidered\sexperimental\sand\smay\sbe\sremoved\sif\swe\sfind\sadverse\simpact\nelsewhere\sin\sthe\ssystem.\s(CVS\s4732)
-D 2008-01-20T23:19:57
+C Remove\ssome\sunused\sbranches\sfrom\sinternal\sfunction\ssqlite3PagerDontRollback().\s(CVS\s4733)
+D 2008-01-21T13:04:35
 F Makefile.arm-wince-mingw32ce-gcc ac5f7b2cef0cd850d6f755ba6ee4ab961b1fadf7
 F Makefile.in 30789bf70614bad659351660d76b8e533f3340e9
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -124,7 +124,7 @@ F src/os_unix.c e4daef7628f690fa2b188af3632fb18f96525946
 F src/os_unix.h 5768d56d28240d3fe4537fac08cc85e4fb52279e
 F src/os_win.c c832d528ea774c7094d887749d71884984c9034c
 F src/os_win.h 41a946bea10f61c158ce8645e7646b29d44f122b
-F src/pager.c a55923e2de46b81868da9e6e6f348e2978d477b9
+F src/pager.c fae75270b4e2b2542b905791087f0c52142974f8
 F src/pager.h f504f7ae84060fee0416a853e368d3d113c3d6fa
 F src/parse.y 2ae06e8d3190faace49c5b82e7cea1fc60d084a1
 F src/pragma.c 155315ee3e6a861a0060ba4d184dfffd08ebbc03
@@ -608,7 +608,7 @@ F www/tclsqlite.tcl 8be95ee6dba05eabcd27a9d91331c803f2ce2130
 F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
 F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
 F www/whentouse.tcl fc46eae081251c3c181bd79c5faef8195d7991a5
-P 010f7b780cb9c8f21af9ce810494fbd2be98a13f
-R a77c92cd50edbd9b3113d32c480fb532
-U drh
-Z 428dd7074c3ab6d6dfe6113da7ace6b5
+P 0bf4e7fefdbbf7be4e32195473563158f22f1869
+R 431eb43674e4abe644622d49d27f61d8
+U danielk1977
+Z 19f9e86a1ac105470be774b290b8b793
diff --git a/manifest.uuid b/manifest.uuid
index a2f02a5e58..04228ab1d4 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-0bf4e7fefdbbf7be4e32195473563158f22f1869
\ No newline at end of file
+3d4252b06b42151874ee437c3a484e818232a5c9
\ No newline at end of file
diff --git a/src/pager.c b/src/pager.c
index 5b81b70f0d..13b0b6d399 100644
--- 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 1.402 2008/01/18 13:42:55 danielk1977 Exp $
+** @(#) $Id: pager.c,v 1.403 2008/01/21 13:04:35 danielk1977 Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 #include "sqliteInt.h"
@@ -4379,36 +4379,51 @@ void sqlite3PagerDontWrite(DbPage *pDbPage){
 ** the PgHdr.needRead flag is set) then this routine acts as a promise
 ** that we will never need to read the page content in the future.
 ** so the needRead flag can be cleared at this point.
+**
+** This routine is only called from a single place in the sqlite btree
+** code (when a leaf is removed from the free-list). This allows the
+** following assumptions to be made about pPg:
+**
+**   1. PagerDontWrite() has been called on the page, OR 
+**      PagerWrite() has not yet been called on the page.
+**
+**   2. The page existed when the transaction was started.
+**
+** Details: DontRollback() (this routine) is only called when a leaf is
+** removed from the free list. DontWrite() is called whenever a page 
+** becomes a free-list leaf.
 */
 void sqlite3PagerDontRollback(DbPage *pPg){
   Pager *pPager = pPg->pPager;
 
   pagerEnter(pPager);
   assert( pPager->state>=PAGER_RESERVED );
-  if( pPager->journalOpen==0 || pPg->alwaysRollback 
-   || pPager->alwaysRollback || MEMDB ){
+
+  /* If the journal file is not open, or DontWrite() has been called on
+  ** this page (DontWrite() sets the alwaysRollback flag), then this
+  ** function is a no-op.
+  */
+  if( pPager->journalOpen==0 || pPg->alwaysRollback || pPager->alwaysRollback ){
     pagerLeave(pPager);
     return;
   }
-  if( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize ){
-    assert( pPager->aInJournal!=0 );
-    pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
-    pPg->inJournal = 1;
-    pPg->needRead = 0;
-    if( pPager->stmtInUse ){
-      pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
-    }
-    PAGERTRACE3("DONT_ROLLBACK page %d of %d\n", pPg->pgno, PAGERID(pPager));
-    IOTRACE(("GARBAGE %p %d\n", pPager, pPg->pgno))
-  }
-  if( pPager->stmtInUse 
-   && !pageInStatement(pPg) 
-   && (int)pPg->pgno<=pPager->stmtSize 
-  ){
-    assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
-    assert( pPager->aInStmt!=0 );
+  assert( !MEMDB );    /* For a memdb, pPager->journalOpen is always 0 */
+
+  /* Check that PagerWrite() has not yet been called on this page, and
+  ** that the page existed when the transaction started.
+  */
+  assert( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize );
+
+  assert( pPager->aInJournal!=0 );
+  pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
+  pPg->inJournal = 1;
+  pPg->needRead = 0;
+  if( pPager->stmtInUse ){
+    assert( pPager->stmtSize <= pPager->origDbSize );
     pPager->aInStmt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
   }
+  PAGERTRACE3("DONT_ROLLBACK page %d of %d\n", pPg->pgno, PAGERID(pPager));
+  IOTRACE(("GARBAGE %p %d\n", pPager, pPg->pgno))
   pagerLeave(pPager);
 }
 
-- 
2.47.3