SQLite

/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** $Id: btree.c,v 1.646 2009/06/29 06:00:37 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

int sqlite3_enable_shared_cache(int enable){
  sqlite3GlobalConfig.sharedCacheEnabled = enable;
  return SQLITE_OK;
}
#endif








#ifdef SQLITE_OMIT_SHARED_CACHE
  /*
  ** The functions querySharedCacheTableLock(), setSharedCacheTableLock(),
  ** and clearAllSharedCacheTableLocks()
  ** manipulate entries in the BtShared.pLock linked list used to store
  ** shared-cache table level locks. If the library is compiled with the
  ** shared-cache feature disabled, then there is only ever one user
  ** of each BtShared structure and so this locking is not necessary. 
  ** So define the lock related functions as no-ops.
  */
  #define querySharedCacheTableLock(a,b,c) SQLITE_OK
  #define setSharedCacheTableLock(a,b,c) SQLITE_OK
  #define clearAllSharedCacheTableLocks(a)
  #define hasSharedCacheTableLock(a,b,c,d) 1
  #define hasReadConflicts(a, b) 0
#endif

#ifndef SQLITE_OMIT_SHARED_CACHE

#ifdef SQLITE_DEBUG
/*
** This function is only used as part of an assert() statement. It checks
** that connection p holds the required locks to read or write to the 
** b-tree with root page iRoot. If so, true is returned. Otherwise, false. 
** For example, when writing to a table b-tree with root-page iRoot via 
** Btree connection pBtree:
**
**    assert( hasSharedCacheTableLock(pBtree, iRoot, 0, WRITE_LOCK) );
**
** When writing to an index b-tree that resides in a sharable database, the 
** caller should have first obtained a lock specifying the root page of
** the corresponding table b-tree. This makes things a bit more complicated,
** as this module treats each b-tree as a separate structure. To determine
** the table b-tree corresponding to the index b-tree being written, this
** function has to search through the database schema.
**
** Instead of a lock on the b-tree rooted at page iRoot, the caller may
** hold a write-lock on the schema table (root page 1). This is also
** acceptable.
*/
static int hasSharedCacheTableLock(
  Btree *pBtree,         /* Handle that must hold lock */
  Pgno iRoot,            /* Root page of b-tree */
  int isIndex,           /* True if iRoot is the root of an index b-tree */
  int eLockType          /* Required lock type (READ_LOCK or WRITE_LOCK) */
){
  Schema *pSchema = (Schema *)pBtree->pBt->pSchema;
  Pgno iTab = 0;
  BtLock *pLock;

  /* If this b-tree database is not shareable, or if the client is reading
  ** and has the read-uncommitted flag set, then no lock is required. 
  ** In these cases return true immediately.  If the client is reading 
  ** or writing an index b-tree, but the schema is not loaded, then return
  ** true also. In this case the lock is required, but it is too difficult
  ** to check if the client actually holds it. This doesn't happen very
  ** often.  */
  if( (pBtree->sharable==0)
   || (eLockType==READ_LOCK && (pBtree->db->flags & SQLITE_ReadUncommitted))
   || (isIndex && (!pSchema || (pSchema->flags&DB_SchemaLoaded)==0 ))
  ){
    return 1;
  }

  /* Figure out the root-page that the lock should be held on. For table
  ** b-trees, this is just the root page of the b-tree being read or
  ** written. For index b-trees, it is the root page of the associated
  ** table.  */
  if( isIndex ){
    HashElem *p;
    for(p=sqliteHashFirst(&pSchema->idxHash); p; p=sqliteHashNext(p)){
      Index *pIdx = (Index *)sqliteHashData(p);
      if( pIdx->tnum==iRoot ){
	iTab = pIdx->pTable->tnum;
      }
    }
  }else{
    iTab = iRoot;
  }

  /* Search for the required lock. Either a write-lock on root-page iTab, a 
  ** write-lock on the schema table, or (if the client is reading) a
  ** read-lock on iTab will suffice. Return 1 if any of these are found.  */
  for(pLock=pBtree->pBt->pLock; pLock; pLock=pLock->pNext){
    if( pLock->pBtree==pBtree 
     && (pLock->iTable==iTab || (pLock->eLock==WRITE_LOCK && pLock->iTable==1))
     && pLock->eLock>=eLockType 
    ){
      return 1;
    }
  }

  /* Failed to find the required lock. */
  return 0;
}

/*
** This function is also used as part of assert() statements only. It 
** returns true if there exist one or more cursors open on the table 
** with root page iRoot that do not belong to either connection pBtree 
** or some other connection that has the read-uncommitted flag set.
**
** For example, before writing to page iRoot:
**
**    assert( !hasReadConflicts(pBtree, iRoot) );
*/
static int hasReadConflicts(Btree *pBtree, Pgno iRoot){
  BtCursor *p;
  for(p=pBtree->pBt->pCursor; p; p=p->pNext){
    if( p->pgnoRoot==iRoot 
     && p->pBtree!=pBtree
     && 0==(p->pBtree->db->flags & SQLITE_ReadUncommitted)
    ){
      return 1;
    }
  }
  return 0;
}
#endif    /* #ifdef SQLITE_DEBUG */

/*
** Query to see if btree handle p may obtain a lock of type eLock 
** (READ_LOCK or WRITE_LOCK) on the table with root-page iTab. Return
** SQLITE_OK if the lock may be obtained (by calling
** setSharedCacheTableLock()), or SQLITE_LOCKED if not.
*/
static int querySharedCacheTableLock(Btree *p, Pgno iTab, u8 eLock){

static void invalidateAllOverflowCache(BtShared *pBt){
  BtCursor *p;
  assert( sqlite3_mutex_held(pBt->mutex) );
  for(p=pBt->pCursor; p; p=p->pNext){
    invalidateOverflowCache(p);
  }
}

/*
** This function is called before modifying the contents of a table
** b-tree to invalidate any incrblob cursors that are open on the
** row or one of the rows being modified. Argument pgnoRoot is the 
** root-page of the table b-tree. 
**
** If argument isClearTable is true, then the entire contents of the
** table is about to be deleted. In this case invalidate all incrblob
** cursors open on any row within the table with root-page pgnoRoot.
**
** Otherwise, if argument isClearTable is false, then the row with
** rowid iRow is being replaced or deleted. In this case invalidate
** only those incrblob cursors open on this specific row.
*/
static void invalidateIncrblobCursors(
  Btree *pBtree,          /* The database file to check */
  Pgno pgnoRoot,          /* Look for read cursors on this btree */
  i64 iRow,               /* The rowid that might be changing */
  int isClearTable        /* True if all rows are being deleted */
){
  BtCursor *p;
  BtShared *pBt = pBtree->pBt;
  assert( sqlite3BtreeHoldsMutex(pBtree) );
  for(p=pBt->pCursor; p; p=p->pNext){
    if( p->isIncrblobHandle && (isClearTable || p->info.nKey==iRow) ){
      p->eState = CURSOR_INVALID;
    }
  }
}

#else
  #define invalidateOverflowCache(x)
  #define invalidateAllOverflowCache(x)
  #define invalidateIncrblobCursors(w,x,y,z)
#endif

/*
** Set bit pgno of the BtShared.pHasContent bitvec. This is called 
** when a page that previously contained data becomes a free-list leaf 
** page.
**

){
  int rc;
  Pgno nPage;
  BtShared *pBt = p->pBt;

  assert( sqlite3BtreeHoldsMutex(p) );
  assert( wrFlag==0 || wrFlag==1 );





  /* The following assert statements verify that if this is a sharable b-tree
  ** database, the connection is holding the required table locks, and that
  ** no other connection has any open cursor that conflicts with this lock.
  **
  ** The exception to this is read-only cursors open on the schema table.
  ** Such a cursor is opened without a lock while reading the database
  ** schema. This is safe because BtShared.mutex is held for the entire
  ** lifetime of this cursor.  */
  assert( (iTable==1 && wrFlag==0) 
       || hasSharedCacheTableLock(p, iTable, pKeyInfo!=0, wrFlag+1) 
  );
  assert( wrFlag==0 || !hasReadConflicts(p, iTable) );




  if( NEVER(wrFlag && pBt->readOnly) ){
    return SQLITE_READONLY;
  }

  if( pBt->pPage1==0 ){
    rc = lockBtreeWithRetry(p);
    if( rc!=SQLITE_OK ){
      return rc;
    }

  if( pFree ){
    sqlite3PageFree(pFree);
  }
  return rc;
}







































































/*
** Insert a new record into the BTree.  The key is given by (pKey,nKey)
** and the data is given by (pData,nData).  The cursor is used only to
** define what table the record should be inserted into.  The cursor
** is left pointing at a random location.
**

  unsigned char *oldCell;
  unsigned char *newCell = 0;

  assert( cursorHoldsMutex(pCur) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( !pBt->readOnly );
  assert( pCur->wrFlag );
  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );

  /* If this is an insert into a table b-tree, invalidate any incrblob 
  ** cursors open on the row being replaced (assuming this is a replace
  ** operation - if it is not, the following is a no-op).  */
  if( pCur->pKeyInfo==0 ){
    invalidateIncrblobCursors(p, pCur->pgnoRoot, nKey, 0);
  }

  if( pCur->eState==CURSOR_FAULT ){
    return pCur->skip;
  }

  /* Save the positions of any other cursors open on this table.
  **
  ** In some cases, the call to sqlite3BtreeMoveto() below is a no-op. For

  int iCellIdx;                        /* Index of cell to delete */
  int iCellDepth;                      /* Depth of node containing pCell */ 

  assert( cursorHoldsMutex(pCur) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( !pBt->readOnly );
  assert( pCur->wrFlag );
  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
  assert( !hasReadConflicts(p, pCur->pgnoRoot) );

  if( NEVER(pCur->aiIdx[pCur->iPage]>=pCur->apPage[pCur->iPage]->nCell) 
   || NEVER(pCur->eState!=CURSOR_VALID)
  ){
    return SQLITE_ERROR;  /* Something has gone awry. */
  }

  /* If this is a delete operation to remove a row from a table b-tree,
  ** invalidate any incrblob cursors open on the row being deleted.  */
  if( pCur->pKeyInfo==0 ){
    invalidateIncrblobCursors(p, pCur->pgnoRoot, pCur->info.nKey, 0);



  }

  iCellDepth = pCur->iPage;
  iCellIdx = pCur->aiIdx[iCellDepth];
  pPage = pCur->apPage[iCellDepth];
  pCell = findCell(pPage, iCellIdx);

** entries in the table.
*/
int sqlite3BtreeClearTable(Btree *p, int iTable, int *pnChange){
  int rc;
  BtShared *pBt = p->pBt;
  sqlite3BtreeEnter(p);
  assert( p->inTrans==TRANS_WRITE );

  /* Invalidate all incrblob cursors open on table iTable (assuming iTable
  ** is the root of a table b-tree - if it is not, the following call is
  ** a no-op).  */
  invalidateIncrblobCursors(p, iTable, 0, 1);

  if( SQLITE_OK==(rc = saveAllCursors(pBt, (Pgno)iTable, 0)) ){


    rc = clearDatabasePage(pBt, (Pgno)iTable, 0, pnChange);
  }
  sqlite3BtreeLeave(p);
  return rc;
}

/*

** Argument pCsr must be a cursor opened for writing on an 
** INTKEY table currently pointing at a valid table entry. 
** This function modifies the data stored as part of that entry.
** Only the data content may only be modified, it is not possible
** to change the length of the data stored.
*/
int sqlite3BtreePutData(BtCursor *pCsr, u32 offset, u32 amt, void *z){


  assert( cursorHoldsMutex(pCsr) );
  assert( sqlite3_mutex_held(pCsr->pBtree->db->mutex) );
  assert( pCsr->isIncrblobHandle );

  restoreCursorPosition(pCsr);
  assert( pCsr->eState!=CURSOR_REQUIRESEEK );
  if( pCsr->eState!=CURSOR_VALID ){
    return SQLITE_ABORT;
  }

  /* Check some preconditions: 
  **   (a) the cursor is open for writing,
  **   (b) there is no read-lock on the table being modified and
  **   (c) the cursor points at a valid row of an intKey table.
  */
  if( !pCsr->wrFlag ){
    return SQLITE_READONLY;
  }
  assert( !pCsr->pBt->readOnly && pCsr->pBt->inTransaction==TRANS_WRITE );
  assert( hasSharedCacheTableLock(pCsr->pBtree, pCsr->pgnoRoot, 0, 2) );
  assert( !hasReadConflicts(pCsr->pBtree, pCsr->pgnoRoot) );





  if( pCsr->eState==CURSOR_INVALID || !pCsr->apPage[pCsr->iPage]->intKey ){
    return SQLITE_ERROR;
  }

  return accessPayload(pCsr, offset, amt, (unsigned char *)z, 0, 1);
}

**    May you share freely, never taking more than you give.
**
*************************************************************************
** Code for testing the btree.c module in SQLite.  This code
** is not included in the SQLite library.  It is used for automated
** testing of the SQLite library.
**
** $Id: test3.c,v 1.105 2009/06/29 06:00:37 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "btreeInt.h"
#include "tcl.h"
#include <stdlib.h>
#include <string.h>

  }
  pBt = sqlite3TestTextToPtr(argv[1]);
  if( Tcl_GetInt(interp, argv[2], &iTable) ) return TCL_ERROR;
  if( Tcl_GetBoolean(interp, argv[3], &wrFlag) ) return TCL_ERROR;
  pCur = (BtCursor *)ckalloc(sqlite3BtreeCursorSize());
  memset(pCur, 0, sqlite3BtreeCursorSize());
  sqlite3BtreeEnter(pBt);
  rc = sqlite3BtreeLockTable(pBt, iTable, wrFlag);
  if( rc==SQLITE_OK ){
    rc = sqlite3BtreeCursor(pBt, iTable, wrFlag, 0, pCur);
  }
  sqlite3BtreeLeave(pBt);
  if( rc ){
    ckfree((char *)pCur);
    Tcl_AppendResult(interp, errorName(rc), 0);
    return TCL_ERROR;
  }
  sqlite3_snprintf(sizeof(zBuf), zBuf,"%p", pCur);

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.867 2009/06/29 06:00:37 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test

#ifndef SQLITE_OMIT_SHARED_CACHE
/* Opcode: TableLock P1 P2 P3 P4 *
**
** Obtain a lock on a particular table. This instruction is only used when
** the shared-cache feature is enabled. 
**
** P1 is the index of the database in sqlite3.aDb[] of the database
** on which the lock is acquired.  A readlock is obtained if P3==0 or
** a write lock if P3==1.
**
** P2 contains the root-page of the table to lock.
**
** P4 contains a pointer to the name of the table being locked. This is only
** used to generate an error message if the lock cannot be obtained.

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains code used to implement incremental BLOB I/O.
**
** $Id: vdbeblob.c,v 1.34 2009/06/29 06:00:37 danielk1977 Exp $
*/

#include "sqliteInt.h"
#include "vdbeInt.h"

#ifndef SQLITE_OMIT_INCRBLOB

  ** The sqlite3_blob_close() function finalizes the vdbe program,
  ** which closes the b-tree cursor and (possibly) commits the 
  ** transaction.
  */
  static const VdbeOpList openBlob[] = {
    {OP_Transaction, 0, 0, 0},     /* 0: Start a transaction */
    {OP_VerifyCookie, 0, 0, 0},    /* 1: Check the schema cookie */
    {OP_TableLock, 0, 0, 0},       /* 2: Acquire a read or write lock */

    /* One of the following two instructions is replaced by an OP_Noop. */


    {OP_OpenRead, 0, 0, 0},        /* 3: Open cursor 0 for reading */
    {OP_OpenWrite, 0, 0, 0},       /* 4: Open cursor 0 for read/write */

    {OP_Variable, 1, 1, 1},        /* 5: Push the rowid to the stack */
    {OP_NotExists, 0, 9, 1},       /* 6: Seek the cursor */
    {OP_Column, 0, 0, 1},          /* 7  */
    {OP_ResultRow, 1, 0, 0},       /* 8  */
    {OP_Close, 0, 0, 0},           /* 9  */
    {OP_Halt, 0, 0, 0},            /* 10 */
  };

  Vdbe *v = 0;
  int rc = SQLITE_OK;
  char *zErr = 0;
  Table *pTab;
  Parse *pParse;

      }
    }

    v = sqlite3VdbeCreate(db);
    if( v ){
      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
      sqlite3VdbeAddOpList(v, sizeof(openBlob)/sizeof(VdbeOpList), openBlob);
      flags = !!flags;                 /* flags = (flags ? 1 : 0); */

      /* Configure the OP_Transaction */
      sqlite3VdbeChangeP1(v, 0, iDb);
      sqlite3VdbeChangeP2(v, 0, flags);

      /* Configure the OP_VerifyCookie */
      sqlite3VdbeChangeP1(v, 1, iDb);
      sqlite3VdbeChangeP2(v, 1, pTab->pSchema->schema_cookie);

      /* Make sure a mutex is held on the table to be accessed */
      sqlite3VdbeUsesBtree(v, iDb); 

      /* Configure the OP_TableLock instruction */
      sqlite3VdbeChangeP1(v, 2, iDb);
      sqlite3VdbeChangeP2(v, 2, pTab->tnum);
      sqlite3VdbeChangeP3(v, 2, flags);
      sqlite3VdbeChangeP4(v, 2, pTab->zName, P4_TRANSIENT);

      /* Remove either the OP_OpenWrite or OpenRead. Set the P2 
      ** parameter of the other to pTab->tnum.  */


      sqlite3VdbeChangeToNoop(v, 4 - flags, 1);
      sqlite3VdbeChangeP2(v, 3 + flags, pTab->tnum);
      sqlite3VdbeChangeP3(v, 3 + flags, iDb);

      /* Configure the number of columns. Configure the cursor to
      ** think that the table has one more column than it really
      ** does. An OP_Column to retrieve this imaginary column will
      ** always return an SQL NULL. This is useful because it means
      ** we can invoke OP_Column to fill in the vdbe cursors type 
      ** and offset cache without causing any IO.
      */
      sqlite3VdbeChangeP4(v, 3+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
      sqlite3VdbeChangeP2(v, 7, pTab->nCol);
      if( !db->mallocFailed ){
        sqlite3VdbeMakeReady(v, 1, 1, 1, 0);
      }
    }
   
    sqlite3BtreeLeaveAll(db);
    rc = sqlite3SafetyOff(db);

#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# Test that it is possible to have two open blob handles on a single
# blob object.
#
# $Id: incrblob2.test,v 1.11 2009/06/29 06:00:37 danielk1977 Exp $
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

ifcapable {!autovacuum || !pragma || !incrblob} {
  finish_test

  do_test incrblob2-5.4 {
    close $blob
    execsql BEGIN db2
    catchsql { INSERT INTO t1 VALUES(4, 'pqrst') } db2
  } {0 {}}

  do_test incrblob2-5.5 {
    set rc [catch { db incrblob -readonly t1 data 1 } msg]
    list $rc $msg
  } {1 {database table is locked: t1}}

  do_test incrblob2-5.6 {
    execsql { PRAGMA read_uncommitted=1 }
    set blob [db incrblob -readonly t1 data 4]
    read $blob
  } {pqrst}

  do_test incrblob2-5.7 {
    catchsql { INSERT INTO t1 VALUES(3, 'klmno') } db2
  } {0 {}}

  do_test incrblob2-5.8 {
    close $blob
  } {}

  db2 close
  db close
  sqlite3_enable_shared_cache $::enable_shared_cache
}

#--------------------------------------------------------------------------

#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library. Specfically
# it tests that the different storage classes (integer, real, text etc.)
# all work correctly.
#
# $Id: types.test,v 1.20 2009/06/29 06:00:37 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Tests in this file are organized roughly as follows:
#
# types-1.*.*: Test that values are stored using the expected storage

}

# Open the table with root-page $rootpage at the btree
# level. Return a list that is the length of each record
# in the table, in the tables default scanning order.
proc record_sizes {rootpage} {
  set bt [btree_open test.db 10 0]
  btree_begin_transaction $bt
  set c [btree_cursor $bt $rootpage 0]
  btree_first $c
  while 1 {
    lappend res [btree_payload_size $c]
    if {[btree_next $c]} break
  }
  btree_close_cursor $c