github.com/whtcorpsinc/milevadb-prod@v0.0.0-20211104133533-f57f4be3b597/causetstore/ekv/iter.go (about)

     1  // Copyright 2020 WHTCORPS INC, 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 ekv
    15  
    16  // NextUntil applies FnKeyCmp to each entry of the iterator until meets some condition.
    17  // It will stop when fn returns true, or iterator is invalid or an error occurs.
    18  func NextUntil(it Iterator, fn FnKeyCmp) error {
    19  	var err error
    20  	for it.Valid() && !fn(it.Key()) {
    21  		err = it.Next()
    22  		if err != nil {
    23  			return err
    24  		}
    25  	}
    26  	return nil
    27  }