io

package
v0.30.0 Latest Latest
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 Go to latest Published: Apr 30, 2025 License: Apache-2.0, MIT Imports: 14 Imported by: 36

Documentation

Overview

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

Index

Constants

This section is empty.

Variables

View Source 
var (
	ErrIsDir            = errors.New("this dag node is a directory")
	ErrCantReadSymlinks = errors.New("cannot currently read symlinks")
	ErrUnkownNodeType   = errors.New("unknown node type")
	ErrSeekNotSupported = errors.New("file does not support seeking")
)

Common errors

View Source 
var DefaultShardWidth = 256

DefaultShardWidth is the default value used for hamt sharding width. Needs to be a power of two (shard entry size) and multiple of 8 (bitfield size).

View Source 
var ErrNotADir = errors.New("merkledag node was not a directory or shard")

ErrNotADir implies that the given node was not a unixfs directory

View Source 
var HAMTShardingSize = int(256 * units.KiB)

HAMTShardingSize is a global option that allows switching to a HAMTDirectory when the BasicDirectory grows above the size (in bytes) signalled by this flag. The default size of 0 disables the option. The size is not the *exact* block size of the encoded BasicDirectory but just the estimated size based byte length of links name and CID (BasicDirectory's ProtoNode doesn't use the Data field so this estimate is pretty accurate).

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 BasicDirectory 

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

BasicDirectory is the basic implementation of `Directory`. All the entries are stored in a single node.

func NewBasicDirectory added in v0.30.0 

func NewBasicDirectory(dserv ipld.DAGService, opts ...DirectoryOption) (*BasicDirectory, error)

NewBasicDirectory creates an empty basic directory with the given options.

func NewBasicDirectoryFromNode added in v0.30.0 

func NewBasicDirectoryFromNode(dserv ipld.DAGService, node *mdag.ProtoNode) *BasicDirectory

NewBasicDirectoryFromNode creates a basic directory wrapping the given ProtoNode.

func (*BasicDirectory) AddChild 

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

AddChild implements the `Directory` interface. It adds (or replaces) a link to the given `node` under `name`.

func (*BasicDirectory) EnumLinksAsync 

func (d *BasicDirectory) EnumLinksAsync(ctx context.Context) <-chan format.LinkResult

EnumLinksAsync returns a channel which will receive Links in the directory as they are enumerated, where order is not guaranteed

func (*BasicDirectory) Find 

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

Find implements the `Directory` interface. 

func (d *BasicDirectory) ForEachLink(_ context.Context, f func(*ipld.Link) error) error

ForEachLink implements the `Directory` interface.

func (*BasicDirectory) GetCidBuilder 

func (d *BasicDirectory) GetCidBuilder() cid.Builder

GetCidBuilder implements the `Directory` interface.

func (*BasicDirectory) GetMaxHAMTFanout added in v0.30.0 

func (d *BasicDirectory) GetMaxHAMTFanout() int

GetMaxLinks returns the configured HAMTFanout. 

func (d *BasicDirectory) GetMaxLinks() int

GetMaxLinks returns the configured MaxLinks.

func (*BasicDirectory) GetNode 

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

GetNode implements the `Directory` interface. 

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

Links implements the `Directory` interface.

func (*BasicDirectory) RemoveChild 

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

RemoveChild implements the `Directory` interface.

func (*BasicDirectory) SetCidBuilder 

func (d *BasicDirectory) SetCidBuilder(builder cid.Builder)

SetCidBuilder implements the `Directory` interface.

func (*BasicDirectory) SetMaxHAMTFanout added in v0.30.0 

func (d *BasicDirectory) SetMaxHAMTFanout(n int)

SetMAXHAMTFanout has no relevance for BasicDirectories. 

func (d *BasicDirectory) SetMaxLinks(n int)

SetMaxLinks sets the maximum number of links for the Directory, but has no side effects until new children are added (in which case the new limit applies).

func (*BasicDirectory) SetStat added in v0.30.0 

func (d *BasicDirectory) SetStat(mode os.FileMode, mtime time.Time)

SetStat has no effect and only exists to support dynamic directories. Use WithStat when creating a new directory instead.

type DagReader 

type DagReader interface {
	ReadSeekCloser
	Size() uint64
	Mode() os.FileMode
	ModTime() time.Time
	CtxReadFull(context.Context, []byte) (int, error)
}

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 retrieval.

type Directory 

type Directory interface {
	// SetCidBuilder sets the CID Builder of the root node.
	SetCidBuilder(cid.Builder)

	// AddChild adds a (name, key) pair to the root node.
	AddChild(context.Context, string, ipld.Node) error

	// ForEachLink applies the given function to Links in the directory.
	ForEachLink(context.Context, func(*ipld.Link) error) error

	// EnumLinksAsync returns a channel which will receive Links in the directory
	// as they are enumerated, where order is not guaranteed
	EnumLinksAsync(context.Context) <-chan format.LinkResult

	// Links returns the all the links in the directory node.
	Links(context.Context) ([]*ipld.Link, 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.
	//
	// Returns os.ErrNotExist if the child does not exist.
	Find(context.Context, string) (ipld.Node, error)

	// RemoveChild removes the child with the given name.
	//
	// Returns os.ErrNotExist if the child doesn't exist.
	RemoveChild(context.Context, string) error

	// GetNode returns the root of this directory.
	GetNode() (ipld.Node, error)

	// GetCidBuilder returns the CID Builder used.
	GetCidBuilder() cid.Builder

	// GetMaxLinks returns the configured value for MaxLinks.
	GetMaxLinks() int

	// SetMaxLinks sets the number of links for the directory. Used when converting
	// between Basic and HAMT.
	SetMaxLinks(n int)

	// GetMaxHAMTFanout returns the configured value for MaxHAMTFanout.
	GetMaxHAMTFanout() int

	// SetMaxHAMTFanout sets the max width of shards when using a HAMT.
	// It must be a power of 2 and multiple of 8. Used when converting
	// between Basic and HAMT.
	SetMaxHAMTFanout(n int)

	// SetStat sets the stat information for the directory. Used when
	// converting between Basic and HAMT.
	SetStat(os.FileMode, time.Time)
}

Directory defines a UnixFS directory. It is used for creating, reading and editing directories. It allows to work with different directory schemes, like the basic or the HAMT implementation.

It just allows to perform explicit edits on a single directory, working with directory trees is out of its scope, they are managed by the MFS layer (which is the main consumer of this interface).

func NewDirectory 

func NewDirectory(dserv ipld.DAGService, opts ...DirectoryOption) (Directory, error)

NewDirectory returns a Directory implemented by DynamicDirectory containing a BasicDirectory that automatically converts to a from a HAMTDirectory based on HAMTShardingSize, MaxLinks and MaxHAMTFanout (when set).

func NewDirectoryFromNode 

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

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

type DirectoryOption added in v0.30.0 

type DirectoryOption func(d Directory)

A DirectoryOption can be used to initialize directories.

func WithCidBuilder added in v0.30.0 

func WithCidBuilder(cb cid.Builder) DirectoryOption

WithCidBuilder sets the CidBuilder for new Directories.

func WithMaxHAMTFanout added in v0.30.0 

func WithMaxHAMTFanout(n int) DirectoryOption

WithMaxHAMTFanout stablishes the maximum fanout factor (number of links) for a HAMT directory or a Dynamic directory with an underlying HAMT directory:

- On Dynamic directories, it specifies the HAMT fanout when a HAMT used. When unset, DefaultShardWidth applies.

- On pure HAMT directories, it sets the ShardWidth, otherwise DefaultShardWidth is used.

HAMT directories require this value to be a power of 2 and a multiple of 8. If it is not the case, it will not be used and DefaultHAMTWidth will be used instead. 

func WithMaxLinks(n int) DirectoryOption

WithMaxLinks stablishes the max number of links allowed for a Basic directory or a Dynamic directory with an underlying Basic directory:

- On Dynamic directories using a BasicDirectory, it can trigger conversion to HAMT when set and exceeded. The subsequent HAMT nodes will use MaxHAMTFanout as ShardWidth when set, or DefaultShardWidth otherwise. Conversion can be triggered too based on HAMTShardingSize.

- On Dynamic directories using a HAMTDirectory, it can trigger conversion to BasicDirectory when the number of directory entries is below MaxLinks (and HAMTShardingSize allows).

- On pure Basic directories, it causes an error when adding more than MaxLinks children.

func WithStat added in v0.30.0 

func WithStat(mode os.FileMode, mtime time.Time) DirectoryOption

WithStat can be used to set the empty directory node permissions.

type DynamicDirectory 

type DynamicDirectory struct {
	Directory
}

DynamicDirectory wraps a Directory interface and provides extra logic to switch from BasicDirectory to HAMTDirectory and backwards based on size.

func (*DynamicDirectory) AddChild 

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

AddChild implements the `Directory` interface. We check when adding new entries if we should switch to HAMTDirectory according to global option(s).

func (*DynamicDirectory) RemoveChild 

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

RemoveChild implements the `Directory` interface. Used in the case where we wrap a HAMTDirectory that might need to be downgraded to a BasicDirectory. The upgrade path is in AddChild.

func (*DynamicDirectory) SetMaxHAMTFanout added in v0.30.0 

func (d *DynamicDirectory) SetMaxHAMTFanout(n int)

SetMaxHAMTFanout sets the maximum shard width for HAMT directories. This operation does not produce any side effect and only takes effect on a conversion from Basic to HAMT directory. 

func (d *DynamicDirectory) SetMaxLinks(n int)

SetMaxLinks sets the maximum number of links for the underlying Basic directory when used. This operation does not produce any side effects, but the new value may trigger Basic-to-HAMT conversions when adding new children to Basic directories, or HAMT-to-Basic conversion when operating with HAMT directories.

func (*DynamicDirectory) SetStat added in v0.30.0 

func (d *DynamicDirectory) SetStat(mode os.FileMode, mtime time.Time)

SetStat sets stats information. This operation does not produce any side effects. It is taken into account when converting from HAMT to basic directory. Mode or mtime can be set independently by using zero for mtime or mode respectively.

type HAMTDirectory 

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

HAMTDirectory is the HAMT implementation of `Directory`. (See package `hamt` for more information.)

func NewHAMTDirectory added in v0.30.0 

func NewHAMTDirectory(dserv ipld.DAGService, sizeChange int, opts ...DirectoryOption) (*HAMTDirectory, error)

NewHAMTDirectory creates an empty HAMT directory with the given options.

func NewHAMTDirectoryFromNode added in v0.30.0 

func NewHAMTDirectoryFromNode(dserv ipld.DAGService, node ipld.Node) (*HAMTDirectory, error)

NewHAMTDirectoryFromNode creates a HAMT directory from the given node, which must correspond to an existing HAMT.

func (*HAMTDirectory) AddChild 

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

AddChild implements the `Directory` interface.

func (*HAMTDirectory) EnumLinksAsync 

func (d *HAMTDirectory) EnumLinksAsync(ctx context.Context) <-chan format.LinkResult

EnumLinksAsync returns a channel which will receive Links in the directory as they are enumerated, where order is not guaranteed

func (*HAMTDirectory) Find 

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

Find implements the `Directory` interface. It will traverse the tree. 

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

ForEachLink implements the `Directory` interface.

func (*HAMTDirectory) GetCidBuilder 

func (d *HAMTDirectory) GetCidBuilder() cid.Builder

GetCidBuilder implements the `Directory` interface.

func (*HAMTDirectory) GetMaxHAMTFanout added in v0.30.0 

func (d *HAMTDirectory) GetMaxHAMTFanout() int

GetMaxHAMTFanout returns the maxHAMTFanout value from a HAMTDirectory. 

func (d *HAMTDirectory) GetMaxLinks() int

GetMaxLinks returns the maxLinks value from a HAMTDirectory.

func (*HAMTDirectory) GetNode 

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

GetNode implements the `Directory` interface. 

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

Links implements the `Directory` interface.

func (*HAMTDirectory) RemoveChild 

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

RemoveChild implements the `Directory` interface.

func (*HAMTDirectory) SetCidBuilder 

func (d *HAMTDirectory) SetCidBuilder(builder cid.Builder)

SetCidBuilder implements the `Directory` interface.

func (*HAMTDirectory) SetMaxHAMTFanout added in v0.30.0 

func (d *HAMTDirectory) SetMaxHAMTFanout(n int)

SetMaxHAMTFanout has no effect and only exists to support Dynamic directories. Max fanout can be set during creation using WithMaxHAMTFanout(). 

func (d *HAMTDirectory) SetMaxLinks(n int)

SetMaxLinks has no effect and only exists to support Dynamic directories.

func (*HAMTDirectory) SetStat added in v0.30.0 

func (d *HAMTDirectory) SetStat(mode os.FileMode, mtime time.Time)

SetStat has no effect and only exists to support Dynamic directories.

type ReadSeekCloser 

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

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

Source Files

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