}

/*
** Invoke the xFileControl method on a particular database.
*/
int sqlite3_file_control(sqlite3 *db, const char *zDbName, int op, void *pArg){
  int rc = SQLITE_ERROR;
  Btree *pBtree;
  int iDb;

  sqlite3_mutex_enter(db->mutex);
  if( zDbName==0 ){
  pBtree = sqlite3DbNameToBtree(db, zDbName);
    iDb = 0;
  }else{
    for(iDb=0; iDb<db->nDb; iDb++){
      if( strcmp(db->aDb[iDb].zName, zDbName)==0 ) break;
    }
  }
  if( iDb<db->nDb ){
    Btree *pBtree = db->aDb[iDb].pBt;
    if( pBtree ){
      Pager *pPager;
      sqlite3_file *fd;
      sqlite3BtreeEnter(pBtree);
      pPager = sqlite3BtreePager(pBtree);
      assert( pPager!=0 );
      fd = sqlite3PagerFile(pPager);
      assert( fd!=0 );
      if( op==SQLITE_FCNTL_FILE_POINTER ){
        *(sqlite3_file**)pArg = fd;
        rc = SQLITE_OK;
      }else if( fd->pMethods ){
        rc = sqlite3OsFileControl(fd, op, pArg);
      }else{
        rc = SQLITE_NOTFOUND;
      }
      sqlite3BtreeLeave(pBtree);
  if( pBtree ){
    Pager *pPager;
    sqlite3_file *fd;
    sqlite3BtreeEnter(pBtree);
    pPager = sqlite3BtreePager(pBtree);
    assert( pPager!=0 );
    fd = sqlite3PagerFile(pPager);
    assert( fd!=0 );
    if( op==SQLITE_FCNTL_FILE_POINTER ){
      *(sqlite3_file**)pArg = fd;
      rc = SQLITE_OK;
    }else if( fd->pMethods ){
      rc = sqlite3OsFileControl(fd, op, pArg);
    }else{
      rc = SQLITE_NOTFOUND;
    }
    sqlite3BtreeLeave(pBtree);
    }
  }
  sqlite3_mutex_leave(db->mutex);
  return rc;   
}

/*
** Interface to the testing logic.

  const char *z = sqlite3_uri_parameter(zFilename, zParam);
  sqlite3_int64 v;
  if( z && sqlite3Atoi64(z, &v, sqlite3Strlen30(z), SQLITE_UTF8)==SQLITE_OK ){
    bDflt = v;
  }
  return bDflt;
}

/*
** Return the Btree pointer identified by zDbName.  Return NULL if not found.
*/
Btree *sqlite3DbNameToBtree(sqlite3 *db, const char *zDbName){
  int i;
  for(i=0; i<db->nDb; i++){
    if( db->aDb[i].pBt
     && (zDbName==0 || sqlite3StrICmp(zDbName, db->aDb[i].zName)==0)
    ){
      return db->aDb[i].pBt;
    }
  }
  return 0;
}

/*
** Return the filename of the database associated with a database
** connection.
*/
const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName){
  int i;
  for(i=0; i<db->nDb; i++){
    if( db->aDb[i].pBt && sqlite3StrICmp(zDbName, db->aDb[i].zName)==0 ){
      return sqlite3BtreeGetFilename(db->aDb[i].pBt);
    }
  }
  return 0;
  Btree *pBt = sqlite3DbNameToBtree(db, zDbName);
  return pBt ? sqlite3BtreeGetFilename(pBt) : 0;
}

/*
** Return 1 if database is read-only or 0 if read/write.  Return -1 if
** no such database exists.
*/
int sqlite3_db_readonly(sqlite3 *db, const char *zDbName){
  Btree *pBt = sqlite3DbNameToBtree(db, zDbName);
  return pBt ? sqlite3PagerIsreadonly(sqlite3BtreePager(pBt)) : -1;
}

** ^The filename returned by this function is the output of the
** xFullPathname method of the [VFS].  ^In other words, the filename
** will be an absolute pathname, even if the filename used
** to open the database originally was a URI or relative pathname.
*/
const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);

/*
** CAPI3REF: Determine if a database is read-only
**
** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
** of connection D is read-only, 0 if it is read/write, and -1 if N is not
** the name of a database in connection C.
*/
int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);

/*
** CAPI3REF: Find the next prepared statement
**
** ^This interface returns a pointer to the next [prepared statement] after
** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
** then this interface returns a pointer to the first prepared statement
** associated with the database connection pDb.  ^If no prepared statement

void sqlite3AddCheckConstraint(Parse*, Expr*);
void sqlite3AddColumnType(Parse*,Token*);
void sqlite3AddDefaultValue(Parse*,ExprSpan*);
void sqlite3AddCollateType(Parse*, Token*);
void sqlite3EndTable(Parse*,Token*,Token*,Select*);
int sqlite3ParseUri(const char*,const char*,unsigned int*,
                    sqlite3_vfs**,char**,char **);
Btree *sqlite3DbNameToBtree(sqlite3*,const char*);
int sqlite3CodeOnce(Parse *);

Bitvec *sqlite3BitvecCreate(u32);
int sqlite3BitvecTest(Bitvec*, u32);
int sqlite3BitvecSet(Bitvec*, u32);
void sqlite3BitvecClear(Bitvec*, u32, void*);
void sqlite3BitvecDestroy(Bitvec*);

    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
  zDbName = Tcl_GetString(objv[2]);
  Tcl_AppendResult(interp, sqlite3_db_filename(db, zDbName), (void*)0);
  return TCL_OK;
}

/*
** Usage:  sqlite3_db_readonly DB DBNAME
**
** Return 1 or 0 if DBNAME is readonly or not.  Return -1 if DBNAME does
** not exist.
*/
static int test_db_readonly(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3 *db;
  const char *zDbName;
  if( objc!=3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DB DBNAME");
    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
  zDbName = Tcl_GetString(objv[2]);
  Tcl_SetObjResult(interp, Tcl_NewIntObj(sqlite3_db_readonly(db, zDbName)));
  return TCL_OK;
}

/*
** Usage:  sqlite3_soft_heap_limit ?N?
**
** Query or set the soft heap limit for the current thread.  The
** limit is only changed if the N is present.  The previous limit
** is returned.

     { "sqlite3_stmt_readonly",         test_stmt_readonly ,0 },
     { "sqlite3_stmt_busy",             test_stmt_busy     ,0 },
     { "uses_stmt_journal",             uses_stmt_journal ,0 },

     { "sqlite3_release_memory",        test_release_memory,     0},
     { "sqlite3_db_release_memory",     test_db_release_memory,  0},
     { "sqlite3_db_filename",           test_db_filename,        0},
     { "sqlite3_db_readonly",           test_db_readonly,        0},
     { "sqlite3_soft_heap_limit",       test_soft_heap_limit,    0},
     { "sqlite3_thread_cleanup",        test_thread_cleanup,     0},
     { "sqlite3_pager_refcounts",       test_pager_refcounts,    0},

     { "sqlite3_load_extension",        test_load_extension,     0},
     { "sqlite3_enable_load_extension", test_enable_load,        0},
     { "sqlite3_extended_result_codes", test_extended_result_codes, 0},

do_test pager1.4.7.3 {
  db close
  catch {file attributes test.db-journal -permissions rw-rw-rw-}
  catch {file attributes test.db-journal -readonly 0}
  delete_file test.db-journal
  file exists test.db-journal
} {0}
do_test pager1.4.8.1 {
  catch {file attributes test.db -permissions r--------}
  catch {file attributes test.db -readonly 1}
  sqlite3 db test.db
  db eval { SELECT * FROM t1 }
  sqlite3_db_readonly db main
} {1}
do_test pager1.4.8.2 {
  sqlite3_db_readonly db xyz
} {-1}
do_test pager1.4.8.3 {
  db close
  catch {file attributes test.db -permissions rw-rw-rw-}
  catch {file attributes test.db -readonly 0}
  sqlite3 db test.db
  db eval { SELECT * FROM t1 }
  sqlite3_db_readonly db main
} {0}

#-------------------------------------------------------------------------
# The following tests deal with multi-file commits.
#
# pager1-5.1.*: The case where a multi-file cannot be committed because
#               another connection is holding a SHARED lock on one of the
#               files. After the SHARED lock is removed, the COMMIT succeeds.