github.com/m3db/m3@v1.5.0/src/dbnode/encoding/null.go (about)

     1  // Copyright (c) 2016 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 encoding
    22  
    23  import (
    24  	"fmt"
    25  
    26  	"github.com/m3db/m3/src/dbnode/namespace"
    27  	"github.com/m3db/m3/src/dbnode/ts"
    28  	"github.com/m3db/m3/src/dbnode/x/xio"
    29  	"github.com/m3db/m3/src/x/context"
    30  	xtime "github.com/m3db/m3/src/x/time"
    31  )
    32  
    33  type nullEncoder struct {
    34  	sealed bool
    35  }
    36  
    37  // NewNullEncoder returns a new encoder that performs no operations
    38  func NewNullEncoder() Encoder {
    39  	return &nullEncoder{}
    40  }
    41  
    42  func (e *nullEncoder) Encode(dp ts.Datapoint, timeUnit xtime.Unit, annotation ts.Annotation) error {
    43  	return nil
    44  }
    45  
    46  func (e *nullEncoder) Stream(ctx context.Context) (xio.SegmentReader, bool) {
    47  	return nil, false
    48  }
    49  func (e *nullEncoder) NumEncoded() int { return 0 }
    50  func (e *nullEncoder) LastEncoded() (ts.Datapoint, error) {
    51  	return ts.Datapoint{}, fmt.Errorf("not implemented")
    52  }
    53  
    54  func (e *nullEncoder) LastAnnotationChecksum() (uint64, error) {
    55  	return 0, fmt.Errorf("not implemented")
    56  }
    57  func (e *nullEncoder) Empty() bool                                      { return true }
    58  func (e *nullEncoder) Len() int                                         { return 0 }
    59  func (e *nullEncoder) Seal()                                            { e.sealed = true }
    60  func (e *nullEncoder) Reset(xtime.UnixNano, int, namespace.SchemaDescr) {}
    61  func (e *nullEncoder) Close()                                           {}
    62  func (e *nullEncoder) Discard() ts.Segment                              { return ts.Segment{} }
    63  func (e *nullEncoder) DiscardReset(xtime.UnixNano, int, namespace.SchemaDescr) ts.Segment {
    64  	return ts.Segment{}
    65  }
    66  func (e *nullEncoder) SetSchema(_ namespace.SchemaDescr) {}
    67  
    68  type nullReaderIterator struct{}
    69  
    70  // NewNullReaderIterator returns a new reader iterator that performs no operations
    71  func NewNullReaderIterator() ReaderIterator {
    72  	return &nullReaderIterator{}
    73  }
    74  
    75  func (r *nullReaderIterator) Current() (ts.Datapoint, xtime.Unit, ts.Annotation) {
    76  	return ts.Datapoint{}, xtime.Unit(0), nil
    77  }
    78  func (r *nullReaderIterator) Next() bool { return false }
    79  func (r *nullReaderIterator) Err() error { return fmt.Errorf("not implemented") }
    80  func (r *nullReaderIterator) Close()     {}
    81  func (r *nullReaderIterator) Reset(xio.Reader64, namespace.SchemaDescr) {
    82  }