1	# hub/hub: a file fetched from the hub, and checked against the hash that names
2	# it. bend accepts any prefix of the sha256, and a package's `0x` name is the
3	# first 32 characters of its manifest's digest, so the check is a prefix test.
4	import Base
5	import ../share/sha.bend as Sha
6	
7	# The GET is ezhttp's, run by hub/get. What is kept here is the answer's shape: a status on
8	# its own first line and then the text, the shape a run answers with and the
9	# one curl's answer had, so `R.ok` and `R.text` read it.
10	
11	# a status other than 200 is a miss with the number in it, never a body
12	def get.status(ok: Bool, status: U32, body: String) -> String:
13	  match ok:
14	    case True{}:
15	      "0\n" ++ body
16	    case False{}:
17	      "22\nthe server answered " ++ U32.show(status)
18	
19	# a file url read off the disk. curl served these too, and a test that wants a
20	# body without a server to serve it is the reason to keep them.
21	def get.file.got(got: Maybe<&2, String>, path: String) -> String:
22	  match got:
23	    case None{}:
24	      "2\n" ++ path ++ " is not there"
25	    case Some{s}:
26	      "0\n" ++ s
27	
28	# a body is the one that was asked for when its digest starts with the hash
29	def matches(want: String, +body: String) -> Bool:
30	  String.starts_with(Sha.hex(body), want)
31	
32	# what a fetch answered: the body when it arrived and hashed right, otherwise
33	# the reason, so a caller never mistakes an error page for a package file
34	type Got is Data:
35	  Miss{why: String}
36	  Have{body: String}
37	
38	# the digest's verdict on a body that did arrive
39	def judge.hash(good: Bool, url: String, body: String) -> Got:
40	  match good:
41	    case True{}:
42	      Have{body}
43	    case False{}:
44	      Miss{url ++ " does not hash to what was asked for"}
45	
46	# a fetch judged, once the run and the digest are both known
47	def judge(ok: Bool, good: Bool, url: String, body: String) -> Got:
48	  match ok:
49	    case False{}:
50	      Miss{url ++ ": " ++ body}
51	    case True{}:
52	      judge.hash(good, url, body)
53	
54	# a fetch's outcome on one line
55	def show(got: Got) -> String:
56	  match got:
57	    case Miss{why}:
58	      "miss " ++ why
59	    case Have{body}:
60	      "have " ++ body