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/*
** 2003 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.
**
*************************************************************************
** This file contains code used to implement the ATTACH and DETACH commands.
**
** $Id: attach.c,v 1.5 2003/06/03 01:47:11 drh Exp $
*/
#include "sqliteInt.h"

/*
** This routine is called by the parser to process an ATTACH statement:
**
**     ATTACH DATABASE filename AS dbname
**
** The pFilename and pDbname arguments are the tokens that define the
** filename and dbname in the ATTACH statement.
*/
void sqliteAttach(Parse *pParse, Token *pFilename, Token *pDbname){
  Db *aNew;
  int rc, i;
  char *zFile, *zName;
  sqlite *db;

  if( pParse->explain ) return;
  db = pParse->db;
  if( db->file_format<4 ){
    sqliteErrorMsg(pParse, "cannot attach auxiliary databases to an "
       "older format master database", 0);
    pParse->rc = SQLITE_ERROR;
    return;
  }
  if( db->nDb>=MAX_ATTACHED+2 ){
    sqliteErrorMsg(pParse, "too many attached databases - max %d", 
       MAX_ATTACHED);
    pParse->rc = SQLITE_ERROR;
    return;
  }
  if( db->aDb==db->aDbStatic ){
    aNew = sqliteMalloc( sizeof(db->aDb[0])*3 );
    if( aNew==0 ) return;
    memcpy(aNew, db->aDb, sizeof(db->aDb[0])*2);
  }else{
    aNew = sqliteRealloc(db->aDb, sizeof(db->aDb[0])*(db->nDb+1) );
    if( aNew==0 ) return;
  }
  db->aDb = aNew;
  aNew = &db->aDb[db->nDb++];
  memset(aNew, 0, sizeof(*aNew));
  sqliteHashInit(&aNew->tblHash, SQLITE_HASH_STRING, 0);
  sqliteHashInit(&aNew->idxHash, SQLITE_HASH_STRING, 0);
  sqliteHashInit(&aNew->trigHash, SQLITE_HASH_STRING, 0);
  sqliteHashInit(&aNew->aFKey, SQLITE_HASH_STRING, 1);
  
  zName = 0;
  sqliteSetNString(&zName, pDbname->z, pDbname->n, 0);
  if( zName==0 ) return;
  sqliteDequote(zName);
  for(i=0; i<db->nDb; i++){
    if( db->aDb[i].zName && sqliteStrICmp(db->aDb[i].zName, zName)==0 ){
      sqliteErrorMsg(pParse, "database %z is already in use", zName);
      db->nDb--;
      pParse->rc = SQLITE_ERROR;
      return;
    }
  }
  aNew->zName = zName;
  zFile = 0;
  sqliteSetNString(&zFile, pFilename->z, pFilename->n, 0);
  if( zFile==0 ) return;
  sqliteDequote(zFile);
  rc = sqliteBtreeFactory(db, zFile, 0, MAX_PAGES, &aNew->pBt);
  if( rc ){
    sqliteErrorMsg(pParse, "unable to open database: %s", zFile);
  }
  sqliteFree(zFile);
  db->flags &= ~SQLITE_Initialized;
  if( pParse->nErr ) return;
  rc = sqliteInit(pParse->db, &pParse->zErrMsg);
  if( rc ){
    sqliteResetInternalSchema(db, 0);
    pParse->nErr++;
    pParse->rc = SQLITE_ERROR;
  }
}

/*
** This routine is called by the parser to process a DETACH statement:
**
**    DETACH DATABASE dbname
**
** The pDbname argument is the name of the database in the DETACH statement.
*/
void sqliteDetach(Parse *pParse, Token *pDbname){
  int i;
  sqlite *db;

  if( pParse->explain ) return;
  db = pParse->db;
  for(i=0; i<db->nDb; i++){
    if( db->aDb[i].pBt==0 || db->aDb[i].zName==0 ) continue;
    if( strlen(db->aDb[i].zName)!=pDbname->n ) continue;
    if( sqliteStrNICmp(db->aDb[i].zName, pDbname->z, pDbname->n)==0 ) break;
  }
  if( i>=db->nDb ){
    sqliteErrorMsg(pParse, "no such database: %T", pDbname);
    return;
  }
  if( i<2 ){
    sqliteErrorMsg(pParse, "cannot detach database %T", pDbname);
    return;
  }
  sqliteBtreeClose(db->aDb[i].pBt);
  db->aDb[i].pBt = 0;
  sqliteFree(db->aDb[i].zName);
  sqliteResetInternalSchema(db, i);
  db->nDb--;
  if( i<db->nDb ){
    db->aDb[i] = db->aDb[db->nDb];
    memset(&db->aDb[db->nDb], 0, sizeof(db->aDb[0]));
    sqliteResetInternalSchema(db, i);
  }
}

/*
** Initialize a DbFixer structure.  This routine must be called prior
** to passing the structure to one of the sqliteFixAAAA() routines below.
**
** The return value indicates whether or not fixation is required.  TRUE
** means we do need to fix the database references, FALSE means we do not.
*/
int sqliteFixInit(
  DbFixer *pFix,      /* The fixer to be initialized */
  Parse *pParse,      /* Error messages will be written here */
  int iDb,            /* This is the database that must must be used */
  const char *zType,  /* "view", "trigger", or "index" */
  const Token *pName  /* Name of the view, trigger, or index */
){
  sqlite *db;

  if( iDb<0 || iDb==1 ) return 0;
  db = pParse->db;
  assert( db->nDb>iDb );
  pFix->pParse = pParse;
  pFix->zDb = db->aDb[iDb].zName;
  pFix->zType = zType;
  pFix->pName = pName;
  return 1;
}

/*
** The following set of routines walk through the parse tree and assign
** a specific database to all table references where the database name
** was left unspecified in the original SQL statement.  The pFix structure
** must have been initialized by a prior call to sqliteFixInit().
**
** These routines are used to make sure that an index, trigger, or
** view in one database does not refer to objects in a different database.
** (Exception: indices, triggers, and views in the TEMP database are
** allowed to refer to anything.)  If a reference is explicitly made
** to an object in a different database, an error message is added to
** pParse->zErrMsg and these routines return non-zero.  If everything
** checks out, these routines return 0.
*/
int sqliteFixSrcList(
  DbFixer *pFix,       /* Context of the fixation */
  SrcList *pList       /* The Source list to check and modify */
){
  int i;
  const char *zDb;

  if( pList==0 ) return 0;
  zDb = pFix->zDb;
  for(i=0; i<pList->nSrc; i++){
    if( pList->a[i].zDatabase==0 ){
      pList->a[i].zDatabase = sqliteStrDup(zDb);
    }else if( sqliteStrICmp(pList->a[i].zDatabase,zDb)!=0 ){
      sqliteErrorMsg(pFix->pParse,
         "%s %z cannot reference objects in database %s",
         pFix->zType, sqliteStrNDup(pFix->pName->z, pFix->pName->n),
         pList->a[i].zDatabase);
      return 1;
    }
    if( sqliteFixSelect(pFix, pList->a[i].pSelect) ) return 1;
    if( sqliteFixExpr(pFix, pList->a[i].pOn) ) return 1;
  }
  return 0;
}
int sqliteFixSelect(
  DbFixer *pFix,       /* Context of the fixation */
  Select *pSelect      /* The SELECT statement to be fixed to one database */
){
  while( pSelect ){
    if( sqliteFixExprList(pFix, pSelect->pEList) ){
      return 1;
    }
    if( sqliteFixSrcList(pFix, pSelect->pSrc) ){
      return 1;
    }
    if( sqliteFixExpr(pFix, pSelect->pWhere) ){
      return 1;
    }
    if( sqliteFixExpr(pFix, pSelect->pHaving) ){
      return 1;
    }
    pSelect = pSelect->pPrior;
  }
  return 0;
}
int sqliteFixExpr(
  DbFixer *pFix,     /* Context of the fixation */
  Expr *pExpr        /* The expression to be fixed to one database */
){
  while( pExpr ){
    if( sqliteFixSelect(pFix, pExpr->pSelect) ){
      return 1;
    }
    if( sqliteFixExprList(pFix, pExpr->pList) ){
      return 1;
    }
    if( sqliteFixExpr(pFix, pExpr->pRight) ){
      return 1;
    }
    pExpr = pExpr->pLeft;
  }
  return 0;
}
int sqliteFixExprList(
  DbFixer *pFix,     /* Context of the fixation */
  ExprList *pList    /* The expression to be fixed to one database */
){
  int i;
  if( pList==0 ) return 0;
  for(i=0; i<pList->nExpr; i++){
    if( sqliteFixExpr(pFix, pList->a[i].pExpr) ){
      return 1;
    }
  }
  return 0;
}
int sqliteFixTriggerStep(
  DbFixer *pFix,     /* Context of the fixation */
  TriggerStep *pStep /* The trigger step be fixed to one database */
){
  while( pStep ){
    if( sqliteFixSelect(pFix, pStep->pSelect) ){
      return 1;
    }
    if( sqliteFixExpr(pFix, pStep->pWhere) ){
      return 1;
    }
    if( sqliteFixExprList(pFix, pStep->pExprList) ){
      return 1;
    }
    pStep = pStep->pNext;
  }
  return 0;
}