view mercurial/dummycert.pem @ 39559:07b58266bce3

wireprotov2: implement commands as a generator of objects

Previously, wire protocol version 2 inherited version 1's model of
having separate types to represent the results of different wire
protocol commands.

As I implemented more powerful commands in future commits, I found
I was using a common pattern of returning a special type to hold a
generator. This meant the command function required a closure to
do most of the work. That made logic flow more difficult to follow.
I also noticed that many commands were effectively a sequence of
objects to be CBOR encoded.

I think it makes sense to define version 2 commands as generators.
This way, commands can simply emit the data structures they wish to
send to the client. This eliminates the need for a closure in
command functions and removes encoding from the bodies of commands.

As part of this commit, the handling of response objects has been
moved into the serverreactor class. This puts the reactor in the
driver's seat with regards to CBOR encoding and error handling.
Having error handling in the function that emits frames is
particularly important because exceptions in that function can lead
to things getting in a bad state: I'm fairly certain that uncaught
exceptions in the frame generator were causing deadlocks.

I also introduced a dedicated error type for explicit error reporting
in command handlers. This will be used in subsequent commits.

There's still a bit of work to be done here, especially around
formalizing the error handling "protocol." I've added yet another
TODO to track this so we don't forget.

Test output changed because we're using generators and no longer know
we are at the end of the data until we hit the end of the generator.
This means we can't emit the end-of-stream flag until we've exhausted
the generator. Hence the introduction of 0-sized end-of-stream frames.

Differential Revision: https://phab.mercurial-scm.org/D4472

A dummy certificate that will make OS X 10.6+ Python use the system CA
certificate store:

-----BEGIN CERTIFICATE-----
MIIBIzCBzgIJANjmj39sb3FmMA0GCSqGSIb3DQEBBQUAMBkxFzAVBgNVBAMTDmhn
LmV4YW1wbGUuY29tMB4XDTE0MDgzMDA4NDU1OVoXDTE0MDgyOTA4NDU1OVowGTEX
MBUGA1UEAxMOaGcuZXhhbXBsZS5jb20wXDANBgkqhkiG9w0BAQEFAANLADBIAkEA
mh/ZySGlcq0ALNLmA1gZqt61HruywPrRk6WyrLJRgt+X7OP9FFlEfl2tzHfzqvmK
CtSQoPINWOdAJMekBYFgKQIDAQABMA0GCSqGSIb3DQEBBQUAA0EAF9h49LkSqJ6a
IlpogZuUHtihXeKZBsiktVIDlDccYsNy0RSh9XxUfhk+XMLw8jBlYvcltSXdJ7We
aKdQRekuMQ==
-----END CERTIFICATE-----

This certificate was generated to be syntactically valid but never be usable;
it expired before it became valid.

Created as:

  $ cat > cn.conf << EOT
  > [req]
  > distinguished_name = req_distinguished_name
  > [req_distinguished_name]
  > commonName = Common Name
  > commonName_default = no.example.com
  > EOT
  $ openssl req -nodes -new -x509 -keyout /dev/null \
  >   -out dummycert.pem -days -1 -config cn.conf -subj '/CN=hg.example.com'

To verify the content of this certificate:

  $ openssl x509 -in dummycert.pem -noout -text
  Certificate:
      Data:
          Version: 1 (0x0)
          Serial Number: 15629337334278746470 (0xd8e68f7f6c6f7166)
      Signature Algorithm: sha1WithRSAEncryption
          Issuer: CN=hg.example.com
          Validity
              Not Before: Aug 30 08:45:59 2014 GMT
              Not After : Aug 29 08:45:59 2014 GMT
          Subject: CN=hg.example.com
          Subject Public Key Info:
              Public Key Algorithm: rsaEncryption
                  Public-Key: (512 bit)
                  Modulus:
                      00:9a:1f:d9:c9:21:a5:72:ad:00:2c:d2:e6:03:58:
                      19:aa:de:b5:1e:bb:b2:c0:fa:d1:93:a5:b2:ac:b2:
                      51:82:df:97:ec:e3:fd:14:59:44:7e:5d:ad:cc:77:
                      f3:aa:f9:8a:0a:d4:90:a0:f2:0d:58:e7:40:24:c7:
                      a4:05:81:60:29
                  Exponent: 65537 (0x10001)
      Signature Algorithm: sha1WithRSAEncryption
           17:d8:78:f4:b9:12:a8:9e:9a:22:5a:68:81:9b:94:1e:d8:a1:
           5d:e2:99:06:c8:a4:b5:52:03:94:37:1c:62:c3:72:d1:14:a1:
           f5:7c:54:7e:19:3e:5c:c2:f0:f2:30:65:62:f7:25:b5:25:dd:
           27:b5:9e:68:a7:50:45:e9:2e:31