github.com/m3db/m3@v1.5.0/src/m3ninx/index/iterator.go (about)

     1  // Copyright (c) 2021  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 index
    22  
    23  import (
    24  	"github.com/m3db/m3/src/m3ninx/doc"
    25  	"github.com/m3db/m3/src/m3ninx/postings"
    26  )
    27  
    28  type documentIterator struct {
    29  	retriever    DocRetriever
    30  	postingsIter postings.Iterator
    31  
    32  	currDoc doc.Document
    33  	currID  postings.ID
    34  	closed  bool
    35  	err     error
    36  }
    37  
    38  // NewIterator returns a new Iterator
    39  func NewIterator(r DocRetriever, pi postings.Iterator) doc.Iterator {
    40  	return &documentIterator{
    41  		retriever:    r,
    42  		postingsIter: pi,
    43  	}
    44  }
    45  
    46  func (e *documentIterator) Next() bool {
    47  	if e.closed || e.err != nil || !e.postingsIter.Next() {
    48  		return false
    49  	}
    50  	id := e.postingsIter.Current()
    51  	e.currID = id
    52  
    53  	d, err := e.retriever.Doc(id)
    54  	if err != nil {
    55  		e.err = err
    56  		return false
    57  	}
    58  	e.currDoc = d
    59  	return true
    60  }
    61  
    62  func (e *documentIterator) Current() doc.Document {
    63  	return e.currDoc
    64  }
    65  
    66  func (e *documentIterator) Err() error {
    67  	return e.err
    68  }
    69  
    70  func (e *documentIterator) Close() error {
    71  	if e.closed {
    72  		return errIteratorClosed
    73  	}
    74  	e.closed = true
    75  	e.currDoc = doc.Document{}
    76  	e.currID = postings.ID(0)
    77  	err := e.postingsIter.Close()
    78  	return err
    79  }