github.com/insionng/yougam@v0.0.0-20170714101924-2bc18d833463/libraries/pingcap/tidb/kv/iter.go (about)

     1  // Copyright 2015 PingCAP, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package kv
    15  
    16  import "github.com/insionng/yougam/libraries/juju/errors"
    17  
    18  // NextUntil applies FnKeyCmp to each entry of the iterator until meets some condition.
    19  // It will stop when fn returns true, or iterator is invalid or an error occurs.
    20  func NextUntil(it Iterator, fn FnKeyCmp) error {
    21  	var err error
    22  	for it.Valid() && !fn(it.Key()) {
    23  		err = it.Next()
    24  		if err != nil {
    25  			return errors.Trace(err)
    26  		}
    27  	}
    28  	return nil
    29  }