67 lines
2.7 KiB
Go
67 lines
2.7 KiB
Go
package types
|
|
|
|
// Handler defines the core of the state transition function of an application.
|
|
type Handler func(ctx Context, msg Msg) (*Result, error)
|
|
|
|
// AnteHandler authenticates transactions, before their internal messages are handled.
|
|
// If newCtx.IsZero(), ctx is used instead.
|
|
type AnteHandler func(ctx Context, tx Tx, simulate bool) (newCtx Context, err error)
|
|
|
|
// AnteDecorator wraps the next AnteHandler to perform custom pre- and post-processing.
|
|
type AnteDecorator interface {
|
|
AnteHandle(ctx Context, tx Tx, simulate bool, next AnteHandler) (newCtx Context, err error)
|
|
}
|
|
|
|
// ChainDecorator chains AnteDecorators together with each AnteDecorator
|
|
// wrapping over the decorators further along chain and returns a single AnteHandler.
|
|
//
|
|
// NOTE: The first element is outermost decorator, while the last element is innermost
|
|
// decorator. Decorator ordering is critical since some decorators will expect
|
|
// certain checks and updates to be performed (e.g. the Context) before the decorator
|
|
// is run. These expectations should be documented clearly in a CONTRACT docline
|
|
// in the decorator's godoc.
|
|
//
|
|
// NOTE: Any application that uses GasMeter to limit transaction processing cost
|
|
// MUST set GasMeter with the FIRST AnteDecorator. Failing to do so will cause
|
|
// transactions to be processed with an infinite gasmeter and open a DOS attack vector.
|
|
// Use `ante.SetUpContextDecorator` or a custom Decorator with similar functionality.
|
|
// Returns nil when no AnteDecorator are supplied.
|
|
func ChainAnteDecorators(chain ...AnteDecorator) AnteHandler {
|
|
if len(chain) == 0 {
|
|
return nil
|
|
}
|
|
|
|
// handle non-terminated decorators chain
|
|
if (chain[len(chain)-1] != Terminator{}) {
|
|
chain = append(chain, Terminator{})
|
|
}
|
|
|
|
return func(ctx Context, tx Tx, simulate bool) (Context, error) {
|
|
return chain[0].AnteHandle(ctx, tx, simulate, ChainAnteDecorators(chain[1:]...))
|
|
}
|
|
}
|
|
|
|
// Terminator AnteDecorator will get added to the chain to simplify decorator code
|
|
// Don't need to check if next == nil further up the chain
|
|
// ______
|
|
// <((((((\\\
|
|
// / . }\
|
|
// ;--..--._|}
|
|
// (\ '--/\--' )
|
|
// \\ | '-' :'|
|
|
// \\ . -==- .-|
|
|
// \\ \.__.' \--._
|
|
// [\\ __.--| // _/'--.
|
|
// \ \\ .'-._ ('-----'/ __/ \
|
|
// \ \\ / __>| | '--. |
|
|
// \ \\ | \ | / / /
|
|
// \ '\ / \ | | _/ /
|
|
// \ \ \ | | / /
|
|
// snd \ \ \ /
|
|
type Terminator struct{}
|
|
|
|
// Simply return provided Context and nil error
|
|
func (t Terminator) AnteHandle(ctx Context, _ Tx, _ bool, _ AnteHandler) (Context, error) {
|
|
return ctx, nil
|
|
}
|