store

Documentation

Overview

Package store provides a basic API for modules to interact with kv-stores independently of any implementation of that functionality.

Index

• type Iterator
• type KVStore
• type KVStoreService
• type MemoryStoreService
• type TransientStoreService

Types

type Iterator

type Iterator = dbm.Iterator

Iterator is an alias db's Iterator for convenience.

type KVStore

type KVStore = interface {
	// Get returns nil iff key doesn't exist. Errors on nil key.
	Get(key []byte) ([]byte, error)

	// Has checks if a key exists. Errors on nil key.
	Has(key []byte) (bool, error)

	// Set sets the key. Errors on nil key or value.
	Set(key, value []byte) error

	// Delete deletes the key. Errors on nil key.
	Delete(key []byte) error

	// Iterator iterates over a domain of keys in ascending order. End is exclusive.
	// Start must be less than end, or the Iterator is invalid.
	// Iterator must be closed by caller.
	// To iterate over entire domain, use store.Iterator(nil, nil)
	// CONTRACT: No writes may happen within a domain while an iterator exists over it.
	// Exceptionally allowed for cachekv.Store, safe to write in the modules.
	Iterator(start, end []byte) (Iterator, error)

	// ReverseIterator iterates over a domain of keys in descending order. End is exclusive.
	// Start must be less than end, or the Iterator is invalid.
	// Iterator must be closed by caller.
	// CONTRACT: No writes may happen within a domain while an iterator exists over it.
	// Exceptionally allowed for cachekv.Store, safe to write in the modules.
	ReverseIterator(start, end []byte) (Iterator, error)
}

KVStore describes the basic interface for interacting with key-value stores.

type KVStoreService

type KVStoreService = interface {
	// OpenKVStore retrieves the KVStore from the context.
	OpenKVStore(context.Context) KVStore
}

KVStoreService represents a unique, non-forgeable handle to a regular merkle-tree backed KVStore. It should be provided as a module-scoped dependency by the runtime module being used to build the app.

type MemoryStoreService

type MemoryStoreService = interface {
	// OpenMemoryStore retrieves the memory store from the context.
	OpenMemoryStore(context.Context) KVStore
}

MemoryStoreService represents a unique, non-forgeable handle to a memory-backed KVStore. It should be provided as a module-scoped dependency by the runtime module being used to build the app.

type TransientStoreService

type TransientStoreService = interface {
	// OpenTransientStore retrieves the transient store from the context.
	OpenTransientStore(context.Context) KVStore
}

TransientStoreService represents a unique, non-forgeable handle to a memory-backed KVStore which is reset at the start of every block. It should be provided as a module-scoped dependency by the runtime module being used to build the app.