github.com/dolthub/dolt/go@v0.40.5-0.20240520175717-68db7794bea6/store/nbs/empty_chunk_source.go (about)

     1  // Copyright 2019 Dolthub, 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  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  //
    15  // This file incorporates work covered by the following copyright and
    16  // permission notice:
    17  //
    18  // Copyright 2016 Attic Labs, Inc. All rights reserved.
    19  // Licensed under the Apache License, version 2.0:
    20  // http://www.apache.org/licenses/LICENSE-2.0
    21  
    22  package nbs
    23  
    24  import (
    25  	"bytes"
    26  	"context"
    27  	"io"
    28  
    29  	"golang.org/x/sync/errgroup"
    30  
    31  	"github.com/dolthub/dolt/go/store/chunks"
    32  	"github.com/dolthub/dolt/go/store/hash"
    33  )
    34  
    35  type emptyChunkSource struct{}
    36  
    37  func (ecs emptyChunkSource) has(h hash.Hash) (bool, error) {
    38  	return false, nil
    39  }
    40  
    41  func (ecs emptyChunkSource) hasMany(addrs []hasRecord) (bool, error) {
    42  	return true, nil
    43  }
    44  
    45  func (ecs emptyChunkSource) get(ctx context.Context, h hash.Hash, stats *Stats) ([]byte, error) {
    46  	return nil, nil
    47  }
    48  
    49  func (ecs emptyChunkSource) getMany(ctx context.Context, eg *errgroup.Group, reqs []getRecord, found func(context.Context, *chunks.Chunk), stats *Stats) (bool, error) {
    50  	return true, nil
    51  }
    52  
    53  func (ecs emptyChunkSource) getManyCompressed(ctx context.Context, eg *errgroup.Group, reqs []getRecord, found func(context.Context, CompressedChunk), stats *Stats) (bool, error) {
    54  	return true, nil
    55  }
    56  
    57  func (ecs emptyChunkSource) count() (uint32, error) {
    58  	return 0, nil
    59  }
    60  
    61  func (ecs emptyChunkSource) uncompressedLen() (uint64, error) {
    62  	return 0, nil
    63  }
    64  
    65  func (ecs emptyChunkSource) hash() hash.Hash {
    66  	return hash.Hash{}
    67  }
    68  
    69  func (ecs emptyChunkSource) index() (tableIndex, error) {
    70  	return onHeapTableIndex{}, nil
    71  }
    72  
    73  func (ecs emptyChunkSource) reader(context.Context) (io.ReadCloser, uint64, error) {
    74  	return io.NopCloser(&bytes.Buffer{}), 0, nil
    75  }
    76  
    77  func (ecs emptyChunkSource) getRecordRanges(lookups []getRecord) (map[hash.Hash]Range, error) {
    78  	return map[hash.Hash]Range{}, nil
    79  }
    80  
    81  func (ecs emptyChunkSource) currentSize() uint64 {
    82  	return 0
    83  }
    84  
    85  func (ecs emptyChunkSource) calcReads(reqs []getRecord, blockSize uint64) (reads int, remaining bool, err error) {
    86  	return 0, true, nil
    87  }
    88  
    89  func (ecs emptyChunkSource) close() error {
    90  	return nil
    91  }
    92  
    93  func (ecs emptyChunkSource) clone() (chunkSource, error) {
    94  	return ecs, nil
    95  }