view

Documentation

Overview

Package view defines interfaces for viewing the data stored in an indexer target or an app's original data store.

Index

• type AppData
• type AppState
• type ModuleState
• type ObjectCollection

Types

type AppData

type AppData interface {
	// BlockNum indicates the last block that was persisted. It should be 0 if the target has no data
	// stored and wants to start syncing state.
	// If an indexer starts indexing after a chain's genesis (returning 0), the indexer manager
	// will attempt to perform a catch-up sync of state. Historical events will not be replayed, but an accurate
	// representation of the current state at the height at which indexing began can be reproduced.
	BlockNum() (uint64, error)

	// AppState returns the app state. If the view doesn't persist app state, nil should be returned.
	AppState() AppState
}

AppData is an interface which indexer data targets can implement to allow their app data including state, blocks, transactions and events to be queried. An app's state and event store can also implement this interface to provide an authoritative source of data for comparing with indexed data.

type AppState

type AppState interface {
	// GetModule returns the module state for the given module name. If the module does not exist, nil and no error
	// should be returned.
	GetModule(moduleName string) (ModuleState, error)

	// Modules iterates over all the module state instances in the app. If there is an error getting a module state,
	// modState may be nil and err will be non-nil.
	Modules(f func(modState ModuleState, err error) bool)

	// NumModules returns the number of modules in the app.
	NumModules() (int, error)
}

AppState defines an interface for things that represent application state in schema format.

type ModuleState

type ModuleState interface {
	// ModuleName returns the name of the module.
	ModuleName() string

	// ModuleSchema returns the schema for the module.
	ModuleSchema() schema.ModuleSchema

	// GetObjectCollection returns the object collection for the given object type. If the object collection
	// does not exist, nil and no error should be returned
	GetObjectCollection(objectType string) (ObjectCollection, error)

	// ObjectCollections iterates over all the object collections in the module. If there is an error getting an object
	// collection, objColl may be nil and err will be non-nil.
	ObjectCollections(f func(value ObjectCollection, err error) bool)

	// NumObjectCollections returns the number of object collections in the module.
	NumObjectCollections() (int, error)
}

ModuleState defines an interface for things that represent module state in schema format.

type ObjectCollection

type ObjectCollection interface {
	// ObjectType returns the object type for the collection.
	ObjectType() schema.StateObjectType

	// GetObject returns the object update for the given key if it exists. And error should only be returned
	// if there was an error getting the object update. If the object does not exist but there was no error,
	// then found should be false and the error should be nil.
	GetObject(key interface{}) (update schema.StateObjectUpdate, found bool, err error)

	// AllState iterates over the state of the collection by calling the given function with each item in
	// state represented as an object update. If there is an error getting an object update, the error will be
	// non-nil and the object update should be empty.
	AllState(f func(schema.StateObjectUpdate, error) bool)

	// Len returns the number of objects in the collection.
	Len() (int, error)
}

ObjectCollection is the interface for viewing the state of a collection of objects in a module represented by StateObjectUpdate's for an ObjectType. ObjectUpdates must not include ValueUpdates in the Value field. When ValueUpdates are applied they must be converted to individual value or array format depending on the number of fields in the value. For collections which retain deletions, StateObjectUpdate's with the Delete field set to true should be returned with the latest Value still intact.