blob

Documentation

Overview

Package blob defines types to refer to and retrieve low-level blobs.

Copyright 2013 Google Inc. Modifications Copyright (c) 2014 Simon Zimmermann

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.

Index

• type Blob
  • func NewBlob(ref Ref, size uint32, newReader func() io.ReadCloser) Blob
  • func (b Blob) Open() io.ReadCloser
  • func (b Blob) Size() uint32
  • func (b Blob) SizedInfoRef() SizedInfoRef
  • func (b Blob) SizedRef() SizedRef
• type Fetcher
• type Ref
  • func NewRef(name string) Ref
  • func NewRefFilename(name string) Ref
  • func Parse(ref string) (r Ref, ok bool)
  • func (r Ref) Hash() hash.Hash
  • func (r *Ref) SetHash(h hash.Hash)
  • func (r Ref) String() string
• type SizedInfoRef
• type SizedRef
  • func NewSizedRef(name string) SizedRef
  • func (sr SizedRef) String() string

Types

type Blob

type Blob struct {
	// contains filtered or unexported fields
}

Blob represents a blob. Use the methods Size, SizedRef and Open to query and get data from Blob.

func NewBlob

func NewBlob(ref Ref, size uint32, newReader func() io.ReadCloser) Blob

NewBlob constructs a Blob from its Ref, size and a function that returns an io.ReadCloser from which the blob can be read. Any error in the function newReader when constructing the io.ReadCloser should be returned upon the first call to Read or Close.

func (Blob) Open

func (b Blob) Open() io.ReadCloser

Open returns an io.ReadCloser that can be used to read the blob data. The caller must close the io.ReadCloser when finished.

func (Blob) Size

func (b Blob) Size() uint32

Size returns the size of the blob (in bytes).

func (Blob) SizedInfoRef

func (b Blob) SizedInfoRef() SizedInfoRef

SizedInfoRef returns the SizedInfoRef corresponding to the blob.

func (Blob) SizedRef

func (b Blob) SizedRef() SizedRef

SizedRef returns the SizedRef corresponding to the blob.

type Fetcher

type Fetcher interface {
	// Fetch returns a blob.  If the blob is not found then
	// os.ErrNotExist should be returned for the error (not a wrapped
	// error with a ErrNotExist inside)
	//
	// The caller should close blob.
	Fetch(Ref) (blob io.ReadCloser, size uint32, err error)
}

Fetcher is the minimal interface for retrieving a blob from storage. The full storage interface is blobserver.Storage.

type Ref

type Ref struct {
	Path string `json:"Path"`
	// contains filtered or unexported fields
}

Ref is a reference to a blob.

func NewRef

func NewRef(name string) Ref

func NewRefFilename

func NewRefFilename(name string) Ref

func Parse

func Parse(ref string) (r Ref, ok bool)

func (Ref) Hash

func (r Ref) Hash() hash.Hash

func (*Ref) SetHash

func (r *Ref) SetHash(h hash.Hash)

func (Ref) String

func (r Ref) String() string

type SizedInfoRef

type SizedInfoRef struct {
	Ref
	Size uint32
	MD5  string
}

SizedInfoRef is like a Ref but includes a size and MD5.

type SizedRef

type SizedRef struct {
	Ref
	Size uint32
}

SizedRef is like a Ref but includes a size.

func NewSizedRef

func NewSizedRef(name string) SizedRef

func (SizedRef) String

func (sr SizedRef) String() string