wireprotov2: allow multiple fields to follow revision maps
The *data wire protocol commands emit a series of CBOR values.
Because revision/delta data may be large, their data is emitted
outside the map as a top-level bytestring value.
Before this commit, we'd emit a single optional bytestring
value after the revision descriptor map. This got the job done.
But it was limiting in that we could only send a single field.
And, it required the consumer to know that the presence of a
key in the map implied the existence of a following bytestring
value.
This commit changes the encoding strategy so top-level bytestring
values in the stream are explicitly denoted in a "fieldsfollowing"
key. This key contains an array defining what fields that follow
and the expected size of each field.
By defining things this way, we can easily send N bytestring
values without any ambiguity about their order. In addition,
clients only need to know how to parse ``fieldsfollowing`` to
know if extra values are present.
Because this breaks backwards compatibility, we've bumped the version
number of the wire protocol version 2 API endpoint.
Differential Revision: https://phab.mercurial-scm.org/D4620
$ . $TESTDIR/wireprotohelpers.sh
$ hg init server
$ enablehttpv2 server
$ cd server
$ hg debugdrawdag << EOF
> C D
> |/
> B
> |
> A
> EOF
$ hg up B
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ hg branch branch1
marked working directory as branch branch1
(branches are permanent and global, did you want a bookmark?)
$ echo b1 > foo
$ hg -q commit -A -m 'branch 1'
$ hg up B
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ hg branch branch2
marked working directory as branch branch2
$ echo b2 > foo
$ hg -q commit -A -m 'branch 2'
$ hg log -T '{rev}:{node} {branch} {desc}\n'
5:224161c7589aa48fa83a48feff5e95b56ae327fc branch2 branch 2
4:b5faacdfd2633768cb3152336cc0953381266688 branch1 branch 1
3:be0ef73c17ade3fc89dc41701eb9fc3a91b58282 default D
2:26805aba1e600a82e93661149f2313866a221a7b default C
1:112478962961147124edd43549aedd1a335e44bf default B
0:426bada5c67598ca65036d57d9e4b64b0c1ce7a0 default A
$ hg serve -p $HGPORT -d --pid-file hg.pid -E error.log
$ cat hg.pid > $DAEMON_PIDS
No arguments returns something reasonable
$ sendhttpv2peer << EOF
> command branchmap
> EOF
creating http peer for wire protocol version 2
sending branchmap command
s> POST /api/exp-http-v2-0002/ro/branchmap HTTP/1.1\r\n
s> Accept-Encoding: identity\r\n
s> accept: application/mercurial-exp-framing-0005\r\n
s> content-type: application/mercurial-exp-framing-0005\r\n
s> content-length: 24\r\n
s> host: $LOCALIP:$HGPORT\r\n (glob)
s> user-agent: Mercurial debugwireproto\r\n
s> \r\n
s> \x10\x00\x00\x01\x00\x01\x01\x11\xa1DnameIbranchmap
s> makefile('rb', None)
s> HTTP/1.1 200 OK\r\n
s> Server: testing stub value\r\n
s> Date: $HTTP_DATE$\r\n
s> Content-Type: application/mercurial-exp-framing-0005\r\n
s> Transfer-Encoding: chunked\r\n
s> \r\n
s> 13\r\n
s> \x0b\x00\x00\x01\x00\x02\x011
s> \xa1FstatusBok
s> \r\n
received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
s> 78\r\n
s> p\x00\x00\x01\x00\x02\x001
s> \xa3Gbranch1\x81T\xb5\xfa\xac\xdf\xd2c7h\xcb1R3l\xc0\x953\x81&f\x88Gbranch2\x81T"Aa\xc7X\x9a\xa4\x8f\xa8:H\xfe\xff^\x95\xb5j\xe3\'\xfcGdefault\x82T&\x80Z\xba\x1e`\n
s> \x82\xe96a\x14\x9f#\x13\x86j"\x1a{T\xbe\x0e\xf7<\x17\xad\xe3\xfc\x89\xdcAp\x1e\xb9\xfc:\x91\xb5\x82\x82
s> \r\n
received frame(size=112; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
s> 8\r\n
s> \x00\x00\x00\x01\x00\x02\x002
s> \r\n
s> 0\r\n
s> \r\n
received frame(size=0; request=1; stream=2; streamflags=; type=command-response; flags=eos)
response: {
b'branch1': [
b'\xb5\xfa\xac\xdf\xd2c7h\xcb1R3l\xc0\x953\x81&f\x88'
],
b'branch2': [
b'"Aa\xc7X\x9a\xa4\x8f\xa8:H\xfe\xff^\x95\xb5j\xe3\'\xfc'
],
b'default': [
b'&\x80Z\xba\x1e`\n\x82\xe96a\x14\x9f#\x13\x86j"\x1a{',
b'\xbe\x0e\xf7<\x17\xad\xe3\xfc\x89\xdcAp\x1e\xb9\xfc:\x91\xb5\x82\x82'
]
}
$ cat error.log