persist

Documentation

Overview

Package persist provides codec-based file persistence for arbitrary state types.

Index

• func LoadState(dir, basename string, codec Codec, state any) error
• func SaveState(dir, basename string, codec Codec, state any) error
• type Codec
• type GobCodec
  • func NewGobCodec() *GobCodec
  • func (c *GobCodec) Decode(r io.Reader, state any) error
  • func (c *GobCodec) Encode(w io.Writer, state any) error
  • func (c *GobCodec) Extension() string
• type JSONCodec
  • func NewJSONCodec() *JSONCodec
  • func (c *JSONCodec) Decode(r io.Reader, state any) error
  • func (c *JSONCodec) Encode(w io.Writer, state any) error
  • func (c *JSONCodec) Extension() string
• type Persister
  • func NewPersister[T any](basename string, codec Codec) *Persister[T]
  • func (p *Persister[T]) Load(dir string, restoreState func(*T)) error
  • func (p *Persister[T]) Save(dir string, buildState func() *T) error

Functions

func LoadState

func LoadState(dir, basename string, codec Codec, state any) error

LoadState loads state from a file in the specified directory. The filename is constructed from the basename and the codec's extension. The state parameter must be a pointer to the target struct.

func SaveState

func SaveState(dir, basename string, codec Codec, state any) error

SaveState saves the given state to a file in the specified directory. The filename is constructed from the basename and the codec's extension.

Types

type Codec

type Codec interface {
	// Encode writes the state to the writer.
	Encode(w io.Writer, state any) error
	// Decode reads the state from the reader.
	Decode(r io.Reader, state any) error
	// Extension returns the file extension for this codec (e.g., ".json", ".gob").
	Extension() string
}

Codec defines how state is serialized and deserialized.

type GobCodec

type GobCodec struct{}

GobCodec implements Codec using gob encoding.

func NewGobCodec

func NewGobCodec() *GobCodec

NewGobCodec creates a gob codec.

func (*GobCodec) Decode

func (c *GobCodec) Decode(r io.Reader, state any) error

Decode implements Codec.Decode using gob decoding.

func (*GobCodec) Encode

func (c *GobCodec) Encode(w io.Writer, state any) error

Encode implements Codec.Encode using gob encoding.

func (*GobCodec) Extension

func (c *GobCodec) Extension() string

Extension implements Codec.Extension for gob files.

type JSONCodec

type JSONCodec struct {
	// Indent specifies the indentation string. Empty string means compact JSON.
	Indent string
}

JSONCodec implements Codec using JSON encoding with optional indentation.

func NewJSONCodec

func NewJSONCodec() *JSONCodec

NewJSONCodec creates a JSON codec with pretty-printing (2-space indent).

func (*JSONCodec) Decode

func (c *JSONCodec) Decode(r io.Reader, state any) error

Decode implements Codec.Decode using JSON decoding.

func (*JSONCodec) Encode

func (c *JSONCodec) Encode(w io.Writer, state any) error

Encode implements Codec.Encode using JSON encoding.

func (*JSONCodec) Extension

func (c *JSONCodec) Extension() string

Extension implements Codec.Extension for JSON files.

type Persister

type Persister[T any] struct {
	// contains filtered or unexported fields
}

Persister handles I/O for a specific state type using a Codec.

func NewPersister

func NewPersister[T any](basename string, codec Codec) *Persister[T]

NewPersister creates a persister with the given basename and codec.

func (*Persister[T]) Load

func (p *Persister[T]) Load(dir string, restoreState func(*T)) error

Load restores state from the given directory using the provided restore function.

func (*Persister[T]) Save

func (p *Persister[T]) Save(dir string, buildState func() *T) error

Save writes state to the given directory using the provided build function.