1 | // This module defines the Context type, which carries deadlines, cancellation signals, |
2 | // and other request-scoped values across API boundaries and between processes. |
3 | // Based on: https://github.com/golang/go/tree/master/src/context |
4 | // Last commit: https://github.com/golang/go/commit/52bf14e0e8bdcd73f1ddfb0c4a1d0200097d3ba2 |
5 | module context |
6 | |
7 | import time |
8 | |
9 | // An EmptyContext is never canceled, has no values. |
10 | pub struct EmptyContext {} |
11 | |
12 | pub fn (ctx &EmptyContext) deadline() ?time.Time { |
13 | return none |
14 | } |
15 | |
16 | pub fn (ctx &EmptyContext) done() chan int { |
17 | ch := chan int{} |
18 | ch.close() |
19 | return ch |
20 | } |
21 | |
22 | pub fn (ctx &EmptyContext) err() IError { |
23 | return none |
24 | } |
25 | |
26 | pub fn (ctx &EmptyContext) value(key Key) ?Any { |
27 | return none |
28 | } |
29 | |
30 | pub fn (ctx &EmptyContext) str() string { |
31 | return 'unknown empty Context' |
32 | } |
33 | |
34 | // A BackgroundContext is never canceled, has no values. |
35 | struct BackgroundContext { |
36 | EmptyContext |
37 | } |
38 | |
39 | // str returns a string describing the Context. |
40 | pub fn (ctx &BackgroundContext) str() string { |
41 | return 'context.Background' |
42 | } |
43 | |
44 | // background returns an empty Context. It is never canceled, has no |
45 | // values, and has no deadline. It is typically used by the main function, |
46 | // initialization, and tests, and as the top-level Context for incoming |
47 | // requests. |
48 | pub fn background() Context { |
49 | return &BackgroundContext{} |
50 | } |
51 | |
52 | // A TodoContext is never canceled, has no values, and has no deadline. It is |
53 | // never used for real work. |
54 | struct TodoContext { |
55 | EmptyContext |
56 | } |
57 | |
58 | // str returns a string describing the Context. |
59 | pub fn (ctx &TodoContext) str() string { |
60 | return 'context.TODO' |
61 | } |
62 | |
63 | // todo returns an empty Context. Code should use todo when |
64 | // it's unclear which Context to use or it is not yet available (because the |
65 | // surrounding function has not yet been extended to accept a Context |
66 | // parameter). |
67 | pub fn todo() Context { |
68 | return &TodoContext{} |
69 | } |