/
generator.go
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/
generator.go
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// Copyright (c) 2016-2019 Uber Technologies, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package metainfogen
import (
"fmt"
"github.com/uber/kraken/core"
"github.com/uber/kraken/lib/store"
"github.com/uber/kraken/lib/store/metadata"
)
// Generator wraps static piece length configuration in order to determinstically
// generate metainfo.
type Generator struct {
pieceLengthConfig *pieceLengthConfig
cas *store.CAStore
}
// New creates a new Generator.
func New(config Config, cas *store.CAStore) (*Generator, error) {
plConfig, err := newPieceLengthConfig(config.PieceLengths)
if err != nil {
return nil, fmt.Errorf("piece length config: %s", err)
}
return &Generator{plConfig, cas}, nil
}
// Generate generates metainfo for the blob of d and writes it to disk.
func (g *Generator) Generate(d core.Digest) error {
info, err := g.cas.GetCacheFileStat(d.Hex())
if err != nil {
return fmt.Errorf("cache stat: %s", err)
}
f, err := g.cas.GetCacheFileReader(d.Hex())
if err != nil {
return fmt.Errorf("get cache file: %s", err)
}
pieceLength := g.pieceLengthConfig.get(info.Size())
mi, err := core.NewMetaInfo(d, f, pieceLength)
if err != nil {
return fmt.Errorf("create metainfo: %s", err)
}
if _, err := g.cas.SetCacheFileMetadata(d.Hex(), metadata.NewTorrentMeta(mi)); err != nil {
return fmt.Errorf("set metainfo: %s", err)
}
return nil
}