io

Documentation

Overview

Package io implements convenience objects for working with the ipfs unixfs data format.

Index

• Variables
• func ResolveUnixfsOnce(ctx context.Context, ds ipld.NodeGetter, nd ipld.Node, names []string) (*ipld.Link, []string, error)
• type BufDagReader
  • func NewBufDagReader(b []byte) *BufDagReader
  • func (*BufDagReader) Close() error
  • func (rd *BufDagReader) CtxReadFull(ctx context.Context, b []byte) (int, error)
  • func (rd *BufDagReader) Offset() int64
  • func (rd *BufDagReader) Size() uint64
• type DagReader
  • func NewDagReader(ctx context.Context, n ipld.Node, serv ipld.NodeGetter) (DagReader, error)
• type Directory
  • func NewDirectory(dserv ipld.DAGService) *Directory
  • func NewDirectoryFromNode(dserv ipld.DAGService, nd ipld.Node) (*Directory, error)
  • func (d *Directory) AddChild(ctx context.Context, name string, nd ipld.Node) error
  • func (d *Directory) Find(ctx context.Context, name string) (ipld.Node, error)
  • func (d *Directory) ForEachLink(ctx context.Context, f func(*ipld.Link) error) error
  • func (d *Directory) GetNode() (ipld.Node, error)
  • func (d *Directory) GetPrefix() *cid.Prefix
  • func (d *Directory) Links(ctx context.Context) ([]*ipld.Link, error)
  • func (d *Directory) RemoveChild(ctx context.Context, name string) error
  • func (d *Directory) SetPrefix(prefix *cid.Prefix)
• type PBDagReader
  • func NewPBFileReader(ctx context.Context, n *mdag.ProtoNode, pb *ftpb.Data, serv ipld.NodeGetter) *PBDagReader
  • func (dr *PBDagReader) Close() error
  • func (dr *PBDagReader) CtxReadFull(ctx context.Context, b []byte) (int, error)
  • func (dr *PBDagReader) Offset() int64
  • func (dr *PBDagReader) Read(b []byte) (int, error)
  • func (dr *PBDagReader) Seek(offset int64, whence int) (int64, error)
  • func (dr *PBDagReader) Size() uint64
  • func (dr *PBDagReader) WriteTo(w io.Writer) (int64, error)
• type ReadSeekCloser

Variables

var (
	ErrIsDir            = errors.New("this dag node is a directory")
	ErrCantReadSymlinks = errors.New("cannot currently read symlinks")
)

Common errors

var DefaultShardWidth = 256

DefaultShardWidth is the default value used for hamt sharding width.

var ErrNotADir = fmt.Errorf("merkledag node was not a directory or shard")

ErrNotADir implies that the given node was not a unixfs directory

var ShardSplitThreshold = 1000

ShardSplitThreshold specifies how large of an unsharded directory the Directory code will generate. Adding entries over this value will result in the node being restructured into a sharded object.

var UseHAMTSharding = false

UseHAMTSharding is a global flag that signifies whether or not to use the HAMT sharding scheme for directory creation

Functions

func ResolveUnixfsOnce

func ResolveUnixfsOnce(ctx context.Context, ds ipld.NodeGetter, nd ipld.Node, names []string) (*ipld.Link, []string, error)

ResolveUnixfsOnce resolves a single hop of a path through a graph in a unixfs context. This includes handling traversing sharded directories.

Types

type BufDagReader

type BufDagReader struct {
	*bytes.Reader
}

BufDagReader implements a DagReader that reads from a byte slice using a bytes.Reader. It is used for RawNodes.

func NewBufDagReader

func NewBufDagReader(b []byte) *BufDagReader

NewBufDagReader returns a DAG reader for the given byte slice. BufDagReader is used to read RawNodes.

func (*BufDagReader) Close

func (*BufDagReader) Close() error

Close is a nop.

func (*BufDagReader) CtxReadFull

func (rd *BufDagReader) CtxReadFull(ctx context.Context, b []byte) (int, error)

CtxReadFull reads the slice onto b.

func (*BufDagReader) Offset

func (rd *BufDagReader) Offset() int64

Offset returns the current offset.

func (*BufDagReader) Size

func (rd *BufDagReader) Size() uint64

Size returns the size of the buffer.

type DagReader

type DagReader interface {
	ReadSeekCloser
	Size() uint64
	CtxReadFull(context.Context, []byte) (int, error)
	Offset() int64
}

A DagReader provides read-only read and seek acess to a unixfs file. Different implementations of readers are used for the different types of unixfs/protobuf-encoded nodes.

func NewDagReader

func NewDagReader(ctx context.Context, n ipld.Node, serv ipld.NodeGetter) (DagReader, error)

NewDagReader creates a new reader object that reads the data represented by the given node, using the passed in DAGService for data retreival

type Directory

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

Directory allows to work with UnixFS directory nodes, adding and removing children. It allows to work with different directory schemes, like the classic or the HAMT one.

func NewDirectory

func NewDirectory(dserv ipld.DAGService) *Directory

NewDirectory returns a Directory. It needs a DAGService to add the Children

func NewDirectoryFromNode

func NewDirectoryFromNode(dserv ipld.DAGService, nd ipld.Node) (*Directory, error)

NewDirectoryFromNode loads a unixfs directory from the given IPLD node and DAGService.

func (*Directory) AddChild

func (d *Directory) AddChild(ctx context.Context, name string, nd ipld.Node) error

AddChild adds a (name, key)-pair to the root node.

func (*Directory) Find

func (d *Directory) Find(ctx context.Context, name string) (ipld.Node, error)

Find returns the root node of the file named 'name' within this directory. In the case of HAMT-directories, it will traverse the tree.

func (*Directory) ForEachLink

func (d *Directory) ForEachLink(ctx context.Context, f func(*ipld.Link) error) error

ForEachLink applies the given function to Links in the directory.

func (*Directory) GetNode

func (d *Directory) GetNode() (ipld.Node, error)

GetNode returns the root of this Directory

func (*Directory) GetPrefix

func (d *Directory) GetPrefix() *cid.Prefix

GetPrefix returns the CID Prefix used

func (*Directory) Links

func (d *Directory) Links(ctx context.Context) ([]*ipld.Link, error)

Links returns the all the links in the directory node.

func (*Directory) RemoveChild

func (d *Directory) RemoveChild(ctx context.Context, name string) error

RemoveChild removes the child with the given name.

func (*Directory) SetPrefix

func (d *Directory) SetPrefix(prefix *cid.Prefix)

SetPrefix sets the prefix of the root node

type PBDagReader

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

PBDagReader provides a way to easily read the data contained in a dag.

func NewPBFileReader

func NewPBFileReader(ctx context.Context, n *mdag.ProtoNode, pb *ftpb.Data, serv ipld.NodeGetter) *PBDagReader

NewPBFileReader constructs a new PBFileReader.

func (*PBDagReader) Close

func (dr *PBDagReader) Close() error

Close closes the reader.

func (*PBDagReader) CtxReadFull

func (dr *PBDagReader) CtxReadFull(ctx context.Context, b []byte) (int, error)

CtxReadFull reads data from the DAG structured file

func (*PBDagReader) Offset

func (dr *PBDagReader) Offset() int64

Offset returns the current reader offset

func (*PBDagReader) Read

func (dr *PBDagReader) Read(b []byte) (int, error)

Read reads data from the DAG structured file

func (*PBDagReader) Seek

func (dr *PBDagReader) Seek(offset int64, whence int) (int64, error)

Seek implements io.Seeker, and will seek to a given offset in the file interface matches standard unix seek TODO: check if we can do relative seeks, to reduce the amount of dagreader recreations that need to happen.

func (*PBDagReader) Size

func (dr *PBDagReader) Size() uint64

Size return the total length of the data from the DAG structured file.

func (*PBDagReader) WriteTo

func (dr *PBDagReader) WriteTo(w io.Writer) (int64, error)

WriteTo writes to the given writer.

type ReadSeekCloser

type ReadSeekCloser interface {
	io.Reader
	io.Seeker
	io.Closer
	io.WriterTo
}

A ReadSeekCloser implements interfaces to read, copy, seek and close.