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 1.127 2004/05/11 09:31:32 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.

  return rc;  
}


/*
** Read the meta-information out of a database file.  Meta[0]
** is the number of free pages currently in the database.  Meta[1]
** through meta[15] are available for use by higher layers.  Meta[0]
** is read-only, the others are read/write.
** 
** The schema layer numbers meta values differently.  At the schema
** layer (and the SetCookie and ReadCookie opcodes) the number of
** free pages is not visible.  So Cookie[0] is the same as Meta[1].
*/
int sqlite3BtreeGetMeta(Btree *pBt, int idx, u32 *pMeta){
  int rc;
  unsigned char *pP1;

  assert( idx>=0 && idx<=15 );
  rc = sqlite3pager_get(pBt->pPager, 1, (void**)&pP1);

**
*************************************************************************
** Main file for the SQLite library.  The routines in this file
** implement the programmer interface to the library.  Routines in
** other files are for internal use by SQLite and should not be
** accessed by users of the library.
**
** $Id: main.c,v 1.173 2004/05/11 09:31:32 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>

/*
** A pointer to this structure is used to communicate information

static int sqlite3InitOne(sqlite *db, int iDb, char **pzErrMsg){
  int rc;
  BtCursor *curMain;
  int size;
  Table *pTab;
  char *azArg[6];
  char zDbNum[30];
  int meta[10];
  InitData initData;

  /*
  ** The master database table has a structure like this
  */
  static char master_schema[] = 
     "CREATE TABLE sqlite_master(\n"

  if( db->aDb[iDb].pBt==0 ) return SQLITE_OK;
  rc = sqlite3BtreeCursor(db->aDb[iDb].pBt, MASTER_ROOT, 0, 0, 0, &curMain);
  if( rc!=SQLITE_OK && rc!=SQLITE_EMPTY ){
    sqlite3SetString(pzErrMsg, sqlite3_error_string(rc), (char*)0);
    return rc;
  }

  /* Get the database meta information.
  **
  ** Meta values are as follows:
  **    meta[0]   Schema cookie.  Changes with each schema change.
  **    meta[1]   File format of schema layer.
  **    meta[2]   Size of the page cache.
  **    meta[3]   Synchronous setting.  1:off, 2:normal, 3:full
  **    meta[4]
  **    meta[5]   Pragma temp_store value.  See comments on BtreeFactory
  **    meta[6]
  **    meta[7]
  **    meta[8]
  **    meta[9]
  */
  if( rc==SQLITE_OK ){
    int i;
    for(i=0; rc==SQLITE_OK && i<sizeof(meta)/sizeof(meta[0]); i++){
      rc = sqlite3BtreeGetMeta(db->aDb[iDb].pBt, i+1, &meta[i]);
    }
    if( rc ){
      sqlite3SetString(pzErrMsg, sqlite3_error_string(rc), (char*)0);
      sqlite3BtreeCloseCursor(curMain);
      return rc;
    }
  }else{
    memset(meta, 0, sizeof(meta));
  }
  db->aDb[iDb].schema_cookie = meta[0];
  if( iDb==0 ){
    db->next_cookie = meta[0];
    db->file_format = meta[1];
    size = meta[2];
    if( size==0 ){ size = MAX_PAGES; }
    db->cache_size = size;
    db->safety_level = meta[3];
    if( meta[5]>0 && meta[5]<=2 && db->temp_store==0 ){
      db->temp_store = meta[5];
    }
    if( db->safety_level==0 ) db->safety_level = 2;

    /*
    **  file_format==1    Version 3.0.0.
    */
    if( db->file_format==0 ){
      /* This happens if the database was initially empty */
      db->file_format = 1;
    }else if( db->file_format>1 ){
      sqlite3BtreeCloseCursor(curMain);
      sqlite3SetString(pzErrMsg, "unsupported file format", (char*)0);
      return SQLITE_ERROR;
    }
  }else if( db->file_format!=meta[1] ){
    if( meta[1]==0 ){
      sqlite3SetString(pzErrMsg, "cannot attach empty database: ",
         db->aDb[iDb].zName, (char*)0);
    }else{
      sqlite3SetString(pzErrMsg, "incompatible file format in auxiliary "
         "database: ", db->aDb[iDb].zName, (char*)0);
    }
    sqlite3BtreeClose(db->aDb[iDb].pBt);
    db->aDb[iDb].pBt = 0;
    return SQLITE_FORMAT;
  }
  sqlite3BtreeSetCacheSize(db->aDb[iDb].pBt, db->cache_size);
  sqlite3BtreeSetSafetyLevel(db->aDb[iDb].pBt, meta[3]==0 ? 2 : meta[3]);

  /* Read the schema information out of the schema tables
  */
  assert( db->init.busy );
  sqlite3SafetyOff(db);
  if( rc==SQLITE_EMPTY ){
    /* For an empty database, there is nothing to read */

**
** 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 1.281 2004/05/11 09:31:32 drh Exp $
*/
#include "sqliteInt.h"
#include "os.h"
#include <ctype.h>
#include "vdbeInt.h"

/*

** executing this instruction.
*/
case OP_ReadCookie: {
  int iMeta;
  assert( pOp->p2<SQLITE_N_BTREE_META );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( db->aDb[pOp->p1].pBt!=0 );
  /* The indexing of meta values at the schema layer is off by one from
  ** the indexing in the btree layer.  The btree considers meta[0] to
  ** be the number of free pages in the database (a read-only value)
  ** and meta[1] to be the schema cookie.  The schema layer considers
  ** meta[1] to be the schema cookie.  So we have to shift the index
  ** by one in the following statement.
  */
  rc = sqlite3BtreeGetMeta(db->aDb[pOp->p1].pBt, 1 + pOp->p2, &iMeta);
  pTos++;
  pTos->i = iMeta;
  pTos->flags = MEM_Int;
  break;
}

/* Opcode: SetCookie P1 P2 *

*/
case OP_SetCookie: {
  assert( pOp->p2<SQLITE_N_BTREE_META );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( db->aDb[pOp->p1].pBt!=0 );
  assert( pTos>=p->aStack );
  Integerify(pTos);
  /* See note about index shifting on OP_ReadCookie */
  rc = sqlite3BtreeUpdateMeta(db->aDb[pOp->p1].pBt, 1+pOp->p2, (int)pTos->i);
  Release(pTos);
  pTos--;
  break;
}

/* Opcode: VerifyCookie P1 P2 *

/* Opcode: IsUnique P1 P2 *
**
** The top of the stack is an integer record number.  Call this
** record number R.  The next on the stack is an index key created
** using MakeIdxKey.  Call it K.  This instruction pops R from the
** stack but it leaves K unchanged.
**
** P1 is an index.  So all but the last four bytes of K are an
** index string.  The last four bytes of K are a record number.
**
** This instruction asks if there is an entry in P1 where the
** index string matches K but the record number is different
** from R.  If there is no such entry, then there is an immediate
** jump to P2.  If any entry does exist where the index string
** matches K but the record number is not R, then the record
** number for that entry is pushed onto the stack and control
** falls through to the next instruction.
**
** See also: Distinct, NotFound, NotExists, Found
*/
case OP_IsUnique: {
  int i = pOp->p1;
  Mem *pNos = &pTos[-1];
  Cursor *pCx;
  BtCursor *pCrsr;
  int R;

  /* Pop the value R off the top of the stack
  */
  assert( pNos>=p->aStack );
  Integerify(pTos);
  R = pTos->i;
  pTos--;
  assert( i>=0 && i<=p->nCursor );
  pCx = &p->aCsr[i];
  pCrsr = pCx->pCursor;
  if( pCrsr!=0 ){
    int res, rc;
    int v;         /* The record number on the P1 entry that matches K */
    char *zKey;    /* The value of K */
    int nKey;      /* Number of bytes in K */

    /* Make sure K is a string and make zKey point to K
    */
    Stringify(pNos);
    zKey = pNos->z;
    nKey = pNos->n;
    assert( nKey >= 4 );

    /* Search for an entry in P1 where all but the last four bytes match K.
    ** If there is no such entry, jump immediately to P2.
    */
    assert( p->aCsr[i].deferredMoveto==0 );

    rc = sqlite3BtreeMoveto(pCrsr, zKey, nKey-4, &res);
    if( rc!=SQLITE_OK ) goto abort_due_to_error;
    if( res<0 ){
      rc = sqlite3BtreeNext(pCrsr, &res);
      if( res ){
        pc = pOp->p2 - 1;
        break;
      }
    }
    /* FIX ME - the sqlite2BtreeKeyCompare() function is a temporary hack */
    rc = sqlite2BtreeKeyCompare(pCrsr, zKey, nKey-4, 4, &res); 
    if( rc!=SQLITE_OK ) goto abort_due_to_error;
    if( res>0 ){
      pc = pOp->p2 - 1;
      break;
    }

    /* At this point, pCrsr is pointing to an entry in P1 where all but
    ** the last for bytes of the key match K.  Check to see if the last
    ** four bytes of the key are different from R.  If the last four
    ** bytes equal R then jump immediately to P2.
    */
    sqlite3BtreeKey(pCrsr, nKey - 4, 4, (char*)&v);
    v = keyToInt(v);
    if( v==R ){
      pc = pOp->p2 - 1;
      break;
    }

    /* The last four bytes of the key are different from R.  Convert the

  }else if( (pC = &p->aCsr[i])->pCursor!=0 ){
    sqlite3VdbeCursorMoveto(pC);
    zRec = 0;
    pCrsr = pC->pCursor;
    if( pC->nullRow ){
      payloadSize = 0;
    }else if( pC->keyAsData ){

      u64 pl64;
      assert( !pC->intKey );
      sqlite3BtreeKeySize(pCrsr, &pl64);
      payloadSize = pl64;
    }else{
      sqlite3BtreeDataSize(pCrsr, &payloadSize);
    }
  }else if( pC->pseudoTable ){
    payloadSize = pC->nData;

    if( p->trace && pTos>=p->aStack ){
      int i;
      fprintf(p->trace, "Stack:");
      for(i=0; i>-5 && &pTos[i]>=p->aStack; i--){
        if( pTos[i].flags & MEM_Null ){
          fprintf(p->trace, " NULL");
        }else if( (pTos[i].flags & (MEM_Int|MEM_Str))==(MEM_Int|MEM_Str) ){
          fprintf(p->trace, " si:%lld", pTos[i].i);
        }else if( pTos[i].flags & MEM_Int ){
          fprintf(p->trace, " i:%lld", pTos[i].i);
        }else if( pTos[i].flags & MEM_Real ){
          fprintf(p->trace, " r:%g", pTos[i].r);
        }else if( pTos[i].flags & MEM_Str ){
          int j, k;
          char zBuf[100];
          zBuf[0] = ' ';
          if( pTos[i].flags & MEM_Dyn ){

** MoveTo now.  Return an error code.  If no MoveTo is pending, this
** routine does nothing and returns SQLITE_OK.
*/
int sqlite3VdbeCursorMoveto(Cursor *p){
  if( p->deferredMoveto ){
    int res;
    extern int sqlite3_search_count;
    assert( p->intKey );
    if( p->intKey ){
      sqlite3BtreeMoveto(p->pCursor, 0, p->movetoTarget, &res);
    }else{
      sqlite3BtreeMoveto(p->pCursor,(char*)&p->movetoTarget,sizeof(i64),&res);
    }
    p->lastRecno = keyToInt(p->movetoTarget);
    p->recnoIsValid = res==0;

#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is testing the ATTACH and DETACH commands
# and related functionality.
#
# $Id: attach.test,v 1.15 2004/05/11 09:31:32 drh Exp $
#

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

for {set i 2} {$i<=15} {incr i} {
  file delete -force test$i.db
  file delete -force test$i.db-journal
}

set btree_trace 0
do_test attach-1.1 {
  execsql {
    CREATE TABLE t1(a,b);
    INSERT INTO t1 VALUES(1,2);
    INSERT INTO t1 VALUES(3,4);
    SELECT * FROM t1;
  }