// Delete using a Where Expression
func (m *dbConn) DeleteExpression(where expr.Node) (int, error) {
//return 0, fmt.Errorf("not implemented")
evaluator := vm.Evaluator(where)
var deletedKeys []schema.Key
txn := m.db.Txn(true)
iter, err := txn.Get(m.md.tbl.Name, m.md.primaryIndex)
if err != nil {
txn.Abort()
u.Errorf("could not get values %v", err)
return 0, err
}
deleteLoop:
for {
item := iter.Next()
if item == nil {
break
}
msg, ok := item.(datasource.SqlDriverMessage)
if !ok {
u.Warnf("wat? %T %#v", item, item)
err = fmt.Errorf("unexpected message type %T", item)
break
}
whereValue, ok := evaluator(msg.ToMsgMap(m.md.tbl.FieldPositions))
if !ok {
u.Debugf("could not evaluate where: %v", msg)
}
switch whereVal := whereValue.(type) {
case value.BoolValue:
if whereVal.Val() == false {
//this means do NOT delete
} else {
// Delete!
if err = txn.Delete(m.md.tbl.Name, msg); err != nil {
u.Errorf("could not delete %v", err)
break deleteLoop
}
indexVal := msg.Vals[0]
deletedKeys = append(deletedKeys, schema.NewKeyUint(makeId(indexVal)))
}
case nil:
// ??
u.Warnf("this should be fine, couldn't evaluate so don't delete %v", msg)
default:
if whereVal.Nil() {
// Doesn't match, so don't delete
} else {
u.Warnf("unknown where eval result? %T", whereVal)
}
}
}
if err != nil {
txn.Abort()
return 0, err
}
txn.Commit()
return len(deletedKeys), nil
}
func whereFilter(where expr.Node, task TaskRunner, cols map[string]*expr.Column) MessageHandler {
out := task.MessageOut()
evaluator := vm.Evaluator(where)
return func(ctx *Context, msg datasource.Message) bool {
var whereValue value.Value
var ok bool
switch mt := msg.(type) {
case *datasource.SqlDriverMessage:
//u.Debugf("WHERE: T:%T vals:%#v", msg, mt.Vals)
//u.Debugf("cols: %#v", cols)
msgReader := datasource.NewValueContextWrapper(mt, cols)
whereValue, ok = evaluator(msgReader)
case *datasource.SqlDriverMessageMap:
whereValue, ok = evaluator(mt)
//u.Debugf("WHERE: result:%v T:%T vals:%#v", whereValue, msg, mt.Values())
//u.Debugf("cols: %#v", cols)
default:
if msgReader, ok := msg.(expr.ContextReader); ok {
whereValue, ok = evaluator(msgReader)
} else {
u.Errorf("could not convert to message reader: %T", msg)
}
}
//u.Debugf("msg: %#v", msgReader)
//u.Infof("evaluating: ok?%v result=%v where expr:%v", ok, whereValue.ToString(), where.StringAST())
if !ok {
u.Debugf("could not evaluate: %v", msg)
return false
}
switch whereVal := whereValue.(type) {
case value.BoolValue:
if whereVal.Val() == false {
//u.Debugf("Filtering out: T:%T v:%#v", whereVal, whereVal)
return true
}
case nil:
return false
default:
if whereVal.Nil() {
return false
}
}
//u.Debugf("about to send from where to forward: %#v", msg)
select {
case out <- msg:
return true
case <-task.SigChan():
return false
}
}
}
// Delete using a Where Expression
func (m *StaticDataSource) DeleteExpression(where expr.Node) (int, error) {
//return 0, fmt.Errorf("not implemented")
evaluator := vm.Evaluator(where)
deletedKeys := make([]*Key, 0)
m.bt.Ascend(func(a btree.Item) bool {
di, ok := a.(*DriverItem)
if !ok {
u.Warnf("wat? %T %#v", a, a)
return false
}
msgCtx := di.SqlDriverMessageMap
whereValue, ok := evaluator(msgCtx)
if !ok {
u.Debugf("could not evaluate where: %v", msgCtx.Values())
//return deletedCt, fmt.Errorf("Could not evaluate where clause")
return true
}
switch whereVal := whereValue.(type) {
case value.BoolValue:
if whereVal.Val() == false {
//this means do NOT delete
} else {
// Delete!
indexVal := msgCtx.Values()[m.indexCol]
deletedKeys = append(deletedKeys, NewKey(makeId(indexVal)))
}
case nil:
// ??
default:
if whereVal.Nil() {
// Doesn't match, so don't delete
} else {
u.Warnf("unknown type? %T", whereVal)
}
}
return true
})
for _, deleteKey := range deletedKeys {
//u.Debugf("calling delete: %v", deleteKey)
if ct, err := m.Delete(deleteKey); err != nil {
u.Errorf("Could not delete key: %v", deleteKey)
} else if ct != 1 {
u.Errorf("delete should have removed 1 key %v", deleteKey)
}
}
return len(deletedKeys), nil
}
func whereFilter(where expr.Node, task TaskRunner) MessageHandler {
out := task.MessageOut()
evaluator := vm.Evaluator(where)
return func(ctx *Context, msg datasource.Message) bool {
// defer func() {
// if r := recover(); r != nil {
// u.Errorf("crap, %v", r)
// }
// }()
if msgReader, ok := msg.Body().(expr.ContextReader); ok {
whereValue, ok := evaluator(msgReader)
//u.Debugf("msg: %#v", msgReader)
//u.Infof("evaluating: ok?%v result=%v where expr:%v", ok, whereValue.ToString(), where.StringAST())
if !ok {
u.Errorf("could not evaluate: %v", msg)
return false
}
switch whereVal := whereValue.(type) {
case value.BoolValue:
if whereVal.Val() == false {
//u.Debugf("Filtering out")
return true
} else {
//u.Debugf("NOT FILTERED OUT")
}
default:
u.Warnf("unknown type? %T", whereVal)
}
} else {
u.Errorf("could not convert to message reader: %T", msg.Body())
}
//u.Debug("about to send from where to forward")
select {
case out <- msg:
return true
case <-task.SigChan():
return false
}
}
}