Simplifications to pager.c in support of structural coverage testing. (CVS 6927)

FossilOrigin-Name: 7222ad2667b95d6021d9ae47f548b76b224f46aa

manifest

@@ -1,5 +1,5 @@
-C Simplifications\sand\scomment\simprovements\sin\spager.c.\s(CVS\s6926)
-D 2009-07-24T12:35:57
+C Simplifications\sto\spager.c\sin\ssupport\sof\sstructural\scoverage\stesting.\s(CVS\s6927)
+D 2009-07-24T16:32:01
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in df9359da7a726ccb67a45db905c5447d5c00c6ef
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -147,7 +147,7 @@ F src/os_common.h 8c61457df58f1a4bd5f5adc3e90e01b37bf7afbc
 F src/os_os2.c bed77dc26e3a95ce4a204936b9a1ca6fe612fcc5
 F src/os_unix.c cdb2a08b9ce4aa13b3f7b91d4dd60fb48be9f56a
 F src/os_win.c 725c38a524d168ce280446ad8761d731bc516405
-F src/pager.c cc446ee38f0caf5fab47353f769711e02fda7a0d
+F src/pager.c 80910e68f6bde91dc96a3dcb5d8e5edf3505fa0d
 F src/pager.h 5bd96ed838e4156e0effa5ffe746bce4c0112c24
 F src/parse.y bcd46d43fbd23a22b8c020a3eb1806b794794ed5
 F src/pcache.c 1dae135b70a029f81ed66f6e9b5d0db91480d5d0
@@ -492,7 +492,7 @@ F test/notify2.test 195a467e021f74197be2c4fb02d6dee644b8d8db
 F test/notnull.test 44d600f916b770def8b095a9962dbe3be5a70d82
 F test/null.test a8b09b8ed87852742343b33441a9240022108993
 F test/openv2.test af02ed0a9cbc0d2a61b8f35171d4d117e588e4ec
-F test/pager.test d04982df84334a9ed272ed2943b61985be5377ee
+F test/pager.test 2d0abb66c8967ffac4558c0530b31c28706b5e64
 F test/pager2.test d4b7f6b70ff018b9995e622a32526b275f515042
 F test/pager3.test 2323bf27fd5bd887b580247e5bce500ceee994b4
 F test/pageropt.test 3ee6578891baaca967f0bd349e4abfa736229e1a
@@ -741,7 +741,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
-P 5ba880dde8a219543ced6f792c7f9ecdcd8c1cbb
-R b8ba3e500c8750934aa1015f54324e22
+P 2d2f42ca0a24ed8b33f9ad560c76a6c1301c757b
+R d83586425c23d3015fdf0b2326ebc67f
 U drh
-Z bf3ffffd67cf82b5b648dccfa3279f49
+Z eeeb8d7f7200949823d967a49549fa65

manifest.uuid

@@ -1 +1 @@
-2d2f42ca0a24ed8b33f9ad560c76a6c1301c757b
+7222ad2667b95d6021d9ae47f548b76b224f46aa

src/pager.c

@@ -18,7 +18,7 @@
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
 **
-** @(#) $Id: pager.c,v 1.614 2009/07/24 12:35:57 drh Exp $
+** @(#) $Id: pager.c,v 1.615 2009/07/24 16:32:01 drh Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 #include "sqliteInt.h"
@@ -3950,13 +3950,9 @@ DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
   PgHdr *pPg = 0;
   assert( pPager!=0 );
   assert( pgno!=0 );
-
-  if( (pPager->state!=PAGER_UNLOCK)
-   && (pPager->errCode==SQLITE_OK || pPager->errCode==SQLITE_FULL)
-  ){
-    sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &pPg);
-  }
-
+  assert( pPager->pPCache!=0 );
+  assert( pPager->state > PAGER_UNLOCK );
+  sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &pPg);
   return pPg;
 }
 
@@ -4027,10 +4023,10 @@ static int pager_open_journal(Pager *pPager){
   assert( pPager->useJournal );
   assert( pPager->pInJournal==0 );
   
-  /* If already in the error state, this function is a no-op. */
-  if( pPager->errCode ){
-    return pPager->errCode;
-  }
+  /* If already in the error state, this function is a no-op.  But on
+  ** the other hand, this routine is never called if we are already in
+  ** an error state. */
+  if( NEVER(pPager->errCode) ) return pPager->errCode;
 
   /* TODO: Is it really possible to get here with dbSizeValid==0? If not,
   ** the call to PagerPagecount() can be removed.
@@ -4184,14 +4180,14 @@ static int pager_write(PgHdr *pPg){
   Pager *pPager = pPg->pPager;
   int rc = SQLITE_OK;
 
-  /* Check for errors
+  /* If an error has been previously detected, we should not be
+  ** calling this routine.  Repeat the error for robustness.
   */
-  if( pPager->errCode ){ 
-    return pPager->errCode;
-  }
-  if( pPager->readOnly ){
-    return SQLITE_PERM;
-  }
+  if( NEVER(pPager->errCode) )  return pPager->errCode;
+
+  /* Higher-level routines never call this function if database is not
+  ** writable.  But check anyway, just for robustness. */
+  if( NEVER(pPager->readOnly) ) return SQLITE_PERM;
 
   assert( !pPager->setMaster );
 
@@ -4504,9 +4500,11 @@ static int pager_incr_changecounter(Pager *pPager, int isDirectMode){
     assert( pPgHdr==0 || rc==SQLITE_OK );
 
     /* If page one was fetched successfully, and this function is not
-    ** operating in direct-mode, make page 1 writable.
+    ** operating in direct-mode, make page 1 writable.  When not in 
+    ** direct mode, page 1 is always held in cache and hence the PagerGet()
+    ** above is always successful - hence the ALWAYS on rc==SQLITE_OK.
     */
-    if( rc==SQLITE_OK && !DIRECT_MODE ){
+    if( !DIRECT_MODE && ALWAYS(rc==SQLITE_OK) ){
       rc = sqlite3PagerWrite(pPgHdr);
     }
 
@@ -4544,7 +4542,8 @@ static int pager_incr_changecounter(Pager *pPager, int isDirectMode){
 */
 int sqlite3PagerSync(Pager *pPager){
   int rc;                              /* Return code */
-  if( MEMDB || pPager->noSync ){
+  assert( !MEMDB );
+  if( pPager->noSync ){
     rc = SQLITE_OK;
   }else{
     rc = sqlite3OsSync(pPager->fd, pPager->sync_flags);
@@ -4585,6 +4584,9 @@ int sqlite3PagerCommitPhaseOne(
 ){
   int rc = SQLITE_OK;             /* Return code */
 
+  /* The dbOrigSize is never set if journal_mode=OFF */
+  assert( pPager->journalMode!=PAGER_JOURNALMODE_OFF || pPager->dbOrigSize==0 );
+
   /* If a prior error occurred, this routine should not be called.  ROLLBACK
   ** is the appropriate response to an error, not COMMIT.  Guard against
   ** coding errors by repeating the prior error. */
@@ -4659,10 +4661,13 @@ int sqlite3PagerCommitPhaseOne(
     ** that it took at the start of the transaction. Otherwise, the
     ** calls to sqlite3PagerGet() return zeroed pages instead of 
     ** reading data from the database file.
+    **
+    ** When journal_mode==OFF the dbOrigSize is always zero, so this
+    ** block never runs if journal_mode=OFF.
     */
 #ifndef SQLITE_OMIT_AUTOVACUUM
     if( pPager->dbSize<pPager->dbOrigSize 
-     && pPager->journalMode!=PAGER_JOURNALMODE_OFF 
+     && ALWAYS(pPager->journalMode!=PAGER_JOURNALMODE_OFF)
     ){
       Pgno i;                                   /* Iterator variable */
       const Pgno iSkip = PAGER_MJ_PGNO(pPager); /* Pending lock page */

test/pager.test

@@ -11,7 +11,7 @@
 # This file implements regression tests for SQLite library.  The
 # focus of this script is page cache subsystem.
 #
-# $Id: pager.test,v 1.35 2009/06/05 17:09:12 drh Exp $
+# $Id: pager.test,v 1.36 2009/07/24 16:32:01 drh Exp $
 
 
 set testdir [file dirname $argv0]
@@ -55,9 +55,9 @@ do_test pager-2.1 {
 #  } msg]
 #  lappend v $msg
 #} {1 SQLITE_ERROR}
-do_test pager-2.3.1 {
-  set ::gx [page_lookup $::p1 1]
-} {}
+#do_test pager-2.3.1 {
+#  set ::gx [page_lookup $::p1 1]
+#} {}
 do_test pager-2.3.2 {
   pager_stats $::p1
 } {ref 0 page 0 max 10 size -1 state 0 err 0 hit 0 miss 0 ovfl 0}