vitess.io/vitess@v0.16.2/go/vt/vttablet/tabletmanager/vreplication/shard_sorter.go (about)

     1  /*
     2  Copyright 2020 The Vitess Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package vreplication
    18  
    19  import "strings"
    20  
    21  // ShardSorter implements a sort.Sort() function for sorting shard ranges
    22  type ShardSorter []string
    23  
    24  // Len implements the required interface for a sorting function
    25  func (s ShardSorter) Len() int {
    26  	return len(s)
    27  }
    28  
    29  // Swap implements the required interface for a sorting function
    30  func (s ShardSorter) Swap(i, j int) {
    31  	s[i], s[j] = s[j], s[i]
    32  }
    33  
    34  // Key returns the prefix of a shard range
    35  func (s ShardSorter) Key(ind int) string {
    36  	return strings.Split(s[ind], "-")[0]
    37  }
    38  
    39  // Less implements the required interface for a sorting function
    40  func (s ShardSorter) Less(i, j int) bool {
    41  	return s.Key(i) < s.Key(j)
    42  }