Fossil

    g.useAttach = 0;
    g.dbConfig = db_open(zDbName);
    g.zConfigDbType = "configdb";
  }
  g.zConfigDbName = zDbName;
}


/*
** Returns TRUE if zTable exists in the local database but lacks column
** zColumn
*/
static int db_local_table_exists_but_lacks_column(
  const char *zTable,
  const char *zColumn
){
  char *zDef = db_text(0, "SELECT sql FROM %s.sqlite_master"
                   " WHERE name=='%s' /*scan*/",
                   db_name("localdb"), zTable);
  int rc = 0;
  if( zDef ){
    char *zPattern = mprintf("* %s *", zColumn);
    rc = sqlite3_strglob(zPattern, zDef)==0;
    fossil_free(zPattern);
    fossil_free(zDef);
  }
  return rc;
}

/*
** If zDbName is a valid local database file, open it and return
** true.  If it is not a valid local database file, return 0.
*/
static int isValidLocalDb(const char *zDbName){
  i64 lsize;
  char *zVFileDef;

  if( file_access(zDbName, F_OK) ) return 0;
  lsize = file_size(zDbName);
  if( lsize%1024!=0 || lsize<4096 ) return 0;
  db_open_or_attach(zDbName, "localdb", 0);
  zVFileDef = db_text(0, "SELECT sql FROM %s.sqlite_master"
                         " WHERE name=='vfile'", db_name("localdb"));
  if( zVFileDef==0 ) return 0;

  /* If the "isexe" column is missing from the vfile table, then
  ** add it now.   This code added on 2010-03-06.  After all users have
  ** upgraded, this code can be safely deleted.
  */
  if( !sqlite3_strglob("* isexe *", zVFileDef) ){
    db_multi_exec("ALTER TABLE vfile ADD COLUMN isexe BOOLEAN DEFAULT 0");
  }

  /* If "islink"/"isLink" columns are missing from tables, then
  ** add them now.   This code added on 2011-01-17 and 2011-08-27.
  ** After all users have upgraded, this code can be safely deleted.
  */
  if( !sqlite3_strglob("* islink *", zVFileDef) ){
    db_multi_exec("ALTER TABLE vfile ADD COLUMN islink BOOLEAN DEFAULT 0");
    if( db_local_table_exists_but_lacks_column("stashfile", "isLink") ){
      db_multi_exec("ALTER TABLE stashfile ADD COLUMN isLink BOOL DEFAULT 0");
    }
    if( db_local_table_exists_but_lacks_column("undo", "isLink") ){
      db_multi_exec("ALTER TABLE undo ADD COLUMN isLink BOOLEAN DEFAULT 0");
    }
    if( db_local_table_exists_but_lacks_column("undo_vfile", "islink") ){
      db_multi_exec("ALTER TABLE undo_vfile ADD COLUMN islink BOOL DEFAULT 0");
    }
  }
  return 1;
}

/*
** Locate the root directory of the local repository tree.  The root
** directory is found by searching for a file named "_FOSSIL_" or ".fslckout"
** that contains a valid repository database.