-
Notifications
You must be signed in to change notification settings - Fork 3.6k
/
handler.go
104 lines (90 loc) · 4.25 KB
/
handler.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
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)
// PostHandler like AnteHandler but it executes after RunMsgs. Runs on success
// or failure and enables use cases like gas refunding.
type PostHandler func(ctx Context, tx Tx, simulate, success bool) (newCtx Context, err error)
// AnteDecorator wraps the next AnteHandler to perform custom pre-processing.
type AnteDecorator interface {
AnteHandle(ctx Context, tx Tx, simulate bool, next AnteHandler) (newCtx Context, err error)
}
// PostDecorator wraps the next PostHandler to perform custom post-processing.
type PostDecorator interface {
PostHandle(ctx Context, tx Tx, simulate, success bool, next PostHandler) (newCtx Context, err error)
}
// ChainAnteDecorators 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:]...))
}
}
// ChainPostDecorators chains PostDecorators together with each PostDecorator
// wrapping over the decorators further along chain and returns a single PostHandler.
//
// 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.
func ChainPostDecorators(chain ...PostDecorator) PostHandler {
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, success bool) (Context, error) {
return chain[0].PostHandle(ctx, tx, simulate, success, ChainPostDecorators(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{}
// AnteHandle returns the provided Context and nil error
func (t Terminator) AnteHandle(ctx Context, _ Tx, _ bool, _ AnteHandler) (Context, error) {
return ctx, nil
}
// PostHandle returns the provided Context and nil error
func (t Terminator) PostHandle(ctx Context, _ Tx, _, _ bool, _ PostHandler) (Context, error) {
return ctx, nil
}