handler.go

package sdk

import (
	abci "github.com/tendermint/abci/types"
	"github.com/tendermint/go-wire/data"
	"github.com/tendermint/tmlibs/log"

	"github.com/cosmos/cosmos-sdk/state"
)

// Handler is anything that processes a transaction
type Handler interface {
	// Checker verifies there are valid fees and estimates work
	Checker
	// Deliver performs the tx once it makes it in the block
	Deliver
	// InitStater sets state from the genesis file
	InitStater
	// InitValidater sets the initial validator set
	InitValidater
	// Named ensures there is a name for the item
	Named

	// TODO????
	// BeginBlock(store state.SimpleDB, hash []byte, header *abci.Header)
}

// Named ensures there is a name for the item
type Named interface {
	Name() string
}

// Checker verifies there are valid fees and estimates work
type Checker interface {
	CheckTx(ctx Context, store state.SimpleDB, tx Tx) (CheckResult, error)
}

// CheckerFunc (like http.HandlerFunc) is a shortcut for making wrappers
type CheckerFunc func(Context, state.SimpleDB, Tx) (CheckResult, error)

func (c CheckerFunc) CheckTx(ctx Context, store state.SimpleDB, tx Tx) (CheckResult, error) {
	return c(ctx, store, tx)
}

// Deliver performs the tx once it makes it in the block
type Deliver interface {
	DeliverTx(ctx Context, store state.SimpleDB, tx Tx) (DeliverResult, error)
}

// DeliverFunc (like http.HandlerFunc) is a shortcut for making wrappers
type DeliverFunc func(Context, state.SimpleDB, Tx) (DeliverResult, error)

func (c DeliverFunc) DeliverTx(ctx Context, store state.SimpleDB, tx Tx) (DeliverResult, error) {
	return c(ctx, store, tx)
}

// InitStater sets state from the genesis file
type InitStater interface {
	InitState(l log.Logger, store state.SimpleDB, module, key, value string) (string, error)
}

// InitStateFunc (like http.HandlerFunc) is a shortcut for making wrappers
type InitStateFunc func(log.Logger, state.SimpleDB, string, string, string) (string, error)

func (c InitStateFunc) InitState(l log.Logger, store state.SimpleDB, module, key, value string) (string, error) {
	return c(l, store, module, key, value)
}

// InitValidater sets the initial validator set
type InitValidater interface {
	InitValidate(log log.Logger, store state.SimpleDB, vals []*abci.Validator)
}

// InitValidateFunc (like http.HandlerFunc) is a shortcut for making wrappers
type InitValidateFunc func(log.Logger, state.SimpleDB, []*abci.Validator)

func (c InitValidateFunc) InitValidate(l log.Logger, store state.SimpleDB, vals []*abci.Validator) {
	c(l, store, vals)
}

//---------- results and some wrappers --------

// Result is a common interface of CheckResult and GetResult
type Result interface {
	GetData() data.Bytes
	GetLog() string
}

func ToABCI(r Result) abci.Result {
	return abci.Result{
		Data: r.GetData(),
		Log:  r.GetLog(),
	}
}

// CheckResult captures any non-error abci result
// to make sure people use error for error cases
type CheckResult struct {
	Data data.Bytes
	Log  string
	// GasAllocated is the maximum units of work we allow this tx to perform
	GasAllocated uint64
	// GasPayment is the total fees for this tx (or other source of payment)
	GasPayment uint64
}

// NewCheck sets the gas used and the response data but no more info
// these are the most common info needed to be set by the Handler
func NewCheck(gasAllocated uint64, log string) CheckResult {
	return CheckResult{
		GasAllocated: gasAllocated,
		Log:          log,
	}
}

var _ Result = CheckResult{}

func (r CheckResult) GetData() data.Bytes {
	return r.Data
}

func (r CheckResult) GetLog() string {
	return r.Log
}

// DeliverResult captures any non-error abci result
// to make sure people use error for error cases
type DeliverResult struct {
	Data    data.Bytes
	Log     string
	Diff    []*abci.Validator
	GasUsed uint64
}

var _ Result = DeliverResult{}

func (r DeliverResult) GetData() data.Bytes {
	return r.Data
}

func (r DeliverResult) GetLog() string {
	return r.Log
}

// placeholders
// holders
type NopCheck struct{}

func (_ NopCheck) CheckTx(Context, state.SimpleDB, Tx) (r CheckResult, e error) { return }

type NopDeliver struct{}

func (_ NopDeliver) DeliverTx(Context, state.SimpleDB, Tx) (r DeliverResult, e error) { return }

type NopInitState struct{}

func (_ NopInitState) InitState(log.Logger, state.SimpleDB, string, string, string) (string, error) {
	return "", nil
}

type NopInitValidate struct{}

func (_ NopInitValidate) InitValidate(log log.Logger, store state.SimpleDB, vals []*abci.Validator) {}