1	# Connect error codes (https://connectrpc.com/docs/protocol/#error-codes).
2	# Only these sixteen codes are valid: Connect has no user-defined codes.
3	import Base
4	
5	type Code is Data:
6	  Canceled{}
7	  Unknown{}
8	  InvalidArgument{}
9	  DeadlineExceeded{}
10	  NotFound{}
11	  AlreadyExists{}
12	  PermissionDenied{}
13	  ResourceExhausted{}
14	  FailedPrecondition{}
15	  Aborted{}
16	  OutOfRange{}
17	  Unimplemented{}
18	  Internal{}
19	  Unavailable{}
20	  DataLoss{}
21	  Unauthenticated{}
22	
23	# The wire name, as it appears in an Error's "code" property.
24	def to_string(c: Code) -> String:
25	  match c:
26	    case Canceled{}:
27	      "canceled"
28	    case Unknown{}:
29	      "unknown"
30	    case InvalidArgument{}:
31	      "invalid_argument"
32	    case DeadlineExceeded{}:
33	      "deadline_exceeded"
34	    case NotFound{}:
35	      "not_found"
36	    case AlreadyExists{}:
37	      "already_exists"
38	    case PermissionDenied{}:
39	      "permission_denied"
40	    case ResourceExhausted{}:
41	      "resource_exhausted"
42	    case FailedPrecondition{}:
43	      "failed_precondition"
44	    case Aborted{}:
45	      "aborted"
46	    case OutOfRange{}:
47	      "out_of_range"
48	    case Unimplemented{}:
49	      "unimplemented"
50	    case Internal{}:
51	      "internal"
52	    case Unavailable{}:
53	      "unavailable"
54	    case DataLoss{}:
55	      "data_loss"
56	    case Unauthenticated{}:
57	      "unauthenticated"
58	
59	# The HTTP status a unary error response carries.
60	def to_http(c: Code) -> U32:
61	  match c:
62	    case Canceled{}:
63	      499
64	    case Unknown{}:
65	      500
66	    case InvalidArgument{}:
67	      400
68	    case DeadlineExceeded{}:
69	      504
70	    case NotFound{}:
71	      404
72	    case AlreadyExists{}:
73	      409
74	    case PermissionDenied{}:
75	      403
76	    case ResourceExhausted{}:
77	      429
78	    case FailedPrecondition{}:
79	      400
80	    case Aborted{}:
81	      409
82	    case OutOfRange{}:
83	      400
84	    case Unimplemented{}:
85	      501
86	    case Internal{}:
87	      500
88	    case Unavailable{}:
89	      503
90	    case DataLoss{}:
91	      500
92	    case Unauthenticated{}:
93	      401
94	
95	# All codes, in the order of the spec's table.
96	def all() -> List<&2, Code>:
97	  [Canceled{}, Unknown{}, InvalidArgument{}, DeadlineExceeded{}, NotFound{},
98	   AlreadyExists{}, PermissionDenied{}, ResourceExhausted{}, FailedPrecondition{},
99	   Aborted{}, OutOfRange{}, Unimplemented{}, Internal{}, Unavailable{}, DataLoss{},
100	   Unauthenticated{}]
101	
102	def from_string.pick(hit: Bool, c: Code, rest: Unit -> Maybe<&2, Code>) -> Maybe<&2, Code>:
103	  match hit:
104	    case True{}:
105	      Some{c}
106	    case False{}:
107	      rest(Unit{})
108	
109	def from_string.go(cs: List<&2, Code>, +s: String) -> Maybe<&2, Code>:
110	  match cs:
111	    case Nil{}:
112	      None{}
113	    case Con{+c, rest}:
114	      from_string.pick(String.eq(to_string(c), s), c, u => from_string.go(rest, s))
115	
116	# Parses a wire name; None for anything that is not one of the sixteen codes.
117	def from_string(+s: String) -> Maybe<&2, Code>:
118	  from_string.go(all(), s)
119	
120	# One row of the spec's HTTP-to-code table.
121	type Row is Data:
122	  Row{status: U32, code: Code}
123	
124	def from_http.pick(hit: Bool, c: Code, rest: Unit -> Code) -> Code:
125	  match hit:
126	    case True{}:
127	      c
128	    case False{}:
129	      rest(Unit{})
130	
131	def from_http.go(table: List<&2, Row>, +status: U32) -> Code:
132	  match table:
133	    case Nil{}:
134	      Unknown{}
135	    case Con{Row{+k, c}, rest}:
136	      from_http.pick(U32.is_eq(k, status), c, u => from_http.go(rest, status))
137	
138	# The code a client infers from a non-200 status with no Connect error body.
139	def from_http(+status: U32) -> Code:
140	  from_http.go([Row{400, Internal{}}, Row{401, Unauthenticated{}}, Row{403, PermissionDenied{}},
141	    Row{404, Unimplemented{}}, Row{429, Unavailable{}}, Row{502, Unavailable{}},
142	    Row{503, Unavailable{}}, Row{504, Unavailable{}}], status)