codec

type Decoder ¶ added in v0.6.0

type Decoder func(datamodel.NodeAssembler, io.Reader) error

Decoder defines the shape of a function which produces a Node tree by reading serialized data from an io.Reader. (Decoder doesn't itself return a Node directly, but rather takes a NodeAssembler as an argument, because this allows the caller more control over the Node implementation, as well as some control over allocations.)

The dual of Decoder is an Encoder, which takes a Node and emits its data in a serialized form into an io.Writer. Typically, Decoder and Encoder functions will be found in pairs, and will be expected to be able to round-trip each other's data.

Decoder functions can be used directly. Decoder functions are also often used via a LinkSystem when working with content-addressed storage. LinkSystem methods will helpfully handle the entire process of opening block readers, verifying the hash of the data stream, and applying a Decoder to build Nodes -- all as one step.

A Decoder works with Nodes. If you have a native golang structure, and want to populate it with data using a Decoder, you'll need to either get a NodeAssembler which proxies data into that structure directly, or assemble a Node as intermediate storage and copy the data to the native structure as a separate step.

It may be useful to understand "multicodecs" when working with Decoders. See the documentation on the Encoder function interface for more discussion of multicodecs, the multicodec table, and how this is typically connected to linking.

type Encoder ¶ added in v0.6.0

type Encoder func(datamodel.Node, io.Writer) error

Encoder defines the shape of a function which traverses a Node tree and emits its data in a serialized form into an io.Writer.

The dual of Encoder is a Decoder, which takes a NodeAssembler and fills it with deserialized data consumed from an io.Reader. Typically, Decoder and Encoder functions will be found in pairs, and will be expected to be able to round-trip each other's data.

Encoder functions can be used directly. Encoder functions are also often used via a LinkSystem when working with content-addressed storage. LinkSystem methods will helpfully handle the entire process of traversing a Node tree, encoding this data, hashing it, streaming it to the writer, and committing it -- all as one step.

An Encoder works with Nodes. If you have a native golang structure, and want to serialize it using an Encoder, you'll need to figure out how to transform that golang structure into an ipld.Node tree first.

It may be useful to understand "multicodecs" when working with Encoders. In IPLD, a system called "multicodecs" is typically used to describe encoding foramts. A "multicodec indicator" is a number which describes an encoding; the Link implementations used in IPLD (CIDs) store a multicodec indicator in the Link; and in this library, a multicodec registry exists in the `codec` package, and can be used to associate a multicodec indicator number with an Encoder function. The default EncoderChooser in a LinkSystem will use this multicodec registry to select Encoder functions. However, you can construct a LinkSystem that uses any EncoderChooser you want. It is also possible to have and use Encoder functions that aren't registered as a multicodec at all... we just recommend being cautious of this, because it may make your data less recognizable when working with other systems that use multicodec indicators as part of their communication.

type ErrBudgetExhausted ¶ added in v0.6.0

type ErrBudgetExhausted struct{}

func (e ErrBudgetExhausted) Error() string

type MapSortMode ¶ added in v0.11.0

type MapSortMode uint8

const (
	MapSortMode_None MapSortMode = iota
	MapSortMode_Lexical
	MapSortMode_RFC7049
)