github.com/m3db/m3@v1.5.1-0.20231129193456-75a402aa583b/src/m3ninx/search/searcher/negation.go (about)

     1  // Copyright (c) 2018 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package searcher
    22  
    23  import (
    24  	"github.com/m3db/m3/src/m3ninx/index"
    25  	"github.com/m3db/m3/src/m3ninx/postings"
    26  	"github.com/m3db/m3/src/m3ninx/search"
    27  )
    28  
    29  type negationSearcher struct {
    30  	searcher search.Searcher
    31  }
    32  
    33  // NewNegationSearcher returns a new searcher for finding documents which do not match a
    34  // given query.
    35  func NewNegationSearcher(s search.Searcher) (search.Searcher, error) {
    36  	return &negationSearcher{
    37  		searcher: s,
    38  	}, nil
    39  }
    40  
    41  func (s *negationSearcher) Search(r index.Reader) (postings.List, error) {
    42  	pl, err := r.MatchAll()
    43  	if err != nil {
    44  		return nil, err
    45  	}
    46  
    47  	negatePl, err := s.searcher.Search(r)
    48  	if err != nil {
    49  		return nil, err
    50  	}
    51  
    52  	return pl.Difference(negatePl)
    53  }