wireprotov2: define and implement "filedata" command

Continuing our trend of implementing *data commands for retrieving
information about specific repository data primitives, this commit
implements a command for retrieving data about an individual tracked
file.

The command is very similar to "manifestdata." The only significant
difference is that we have a standalone function for obtaining
storage for a tracked file. This is to provide a monkeypatch point
for extensions to implement path-based access control.

With this API available, wire protocol version 2 now exposes all
data primitives necessary to implement a full clone. Of course,
since "filedata" can only resolve data for a single path at a time,
clients would need to issue N commands to perform a full clone. On
the Firefox repository, this would be ~461k commands. We'll likely
need to implement a file data retrieval command that supports
multiple paths. But that can be implemented later.

Differential Revision: https://phab.mercurial-scm.org/D4490

tests/test-wireproto-command-filedata.t

@@ -0,0 +1,497 b''
+  $ . $TESTDIR/wireprotohelpers.sh
+
+  $ hg init server
+  $ enablehttpv2 server
+  $ cd server
+  $ echo a0 > a
+  $ echo b0 > b
+  $ mkdir -p dir0/child0 dir0/child1 dir1
+  $ echo c0 > dir0/c
+  $ echo d0 > dir0/d
+  $ echo e0 > dir0/child0/e
+  $ echo f0 > dir0/child1/f
+  $ hg -q commit -A -m 'commit 0'
+
+  $ echo a1 > a
+  $ echo d1 > dir0/d
+  $ hg commit -m 'commit 1'
+  $ echo f0 > dir0/child1/f
+  $ hg commit -m 'commit 2'
+  nothing changed
+  [1]
+
+  $ hg -q up -r 0
+  $ echo a2 > a
+  $ hg commit -m 'commit 3'
+  created new head
+
+  $ hg log -G -T '{rev}:{node} {desc}\n'
+  @  2:c8757a2ffe552850d1e0dfe60d295ebf64c196d9 commit 3
+  |
+  | o  1:650165e803375748a94df471e5b58d85763e0b29 commit 1
+  |/
+  o  0:6d85ca1270b377d320098556ba5bfad34a9ee12d commit 0
+  
+
+  $ hg --debug debugindex a
+     rev linkrev nodeid                                   p1                                       p2
+       0       0 2b4eb07319bfa077a40a2f04913659aef0da42da 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000
+       1       1 9a38122997b3ac97be2a9aa2e556838341fdf2cc 2b4eb07319bfa077a40a2f04913659aef0da42da 0000000000000000000000000000000000000000
+       2       2 0879345e39377229634b420c639454156726c6b6 2b4eb07319bfa077a40a2f04913659aef0da42da 0000000000000000000000000000000000000000
+
+  $ hg --debug debugindex dir0/child0/e
+     rev linkrev nodeid                                   p1                                       p2
+       0       0 bbba6c06b30f443d34ff841bc985c4d0827c6be4 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000
+
+  $ hg serve -p $HGPORT -d --pid-file hg.pid -E error.log
+  $ cat hg.pid > $DAEMON_PIDS
+
+Missing arguments is an error
+
+  $ sendhttpv2peer << EOF
+  > command filedata
+  > EOF
+  creating http peer for wire protocol version 2
+  sending filedata command
+  s>     POST /api/exp-http-v2-0001/ro/filedata 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: 23\r\n
+  s>     host: $LOCALIP:$HGPORT\r\n (glob)
+  s>     user-agent: Mercurial debugwireproto\r\n
+  s>     \r\n
+  s>     \x0f\x00\x00\x01\x00\x01\x01\x11\xa1DnameHfiledata
+  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>     45\r\n
+  s>     =\x00\x00\x01\x00\x02\x012
+  s>     \xa2Eerror\xa1GmessageX\x1enodes argument must be definedFstatusEerror
+  s>     \r\n
+  received frame(size=61; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  s>     0\r\n
+  s>     \r\n
+  abort: nodes argument must be defined!
+  [255]
+
+  $ sendhttpv2peer << EOF
+  > command filedata
+  >     nodes eval:[]
+  > EOF
+  creating http peer for wire protocol version 2
+  sending filedata command
+  s>     POST /api/exp-http-v2-0001/ro/filedata 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: 36\r\n
+  s>     host: $LOCALIP:$HGPORT\r\n (glob)
+  s>     user-agent: Mercurial debugwireproto\r\n
+  s>     \r\n
+  s>     \x1c\x00\x00\x01\x00\x01\x01\x11\xa2Dargs\xa1Enodes\x80DnameHfiledata
+  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>     44\r\n
+  s>     <\x00\x00\x01\x00\x02\x012
+  s>     \xa2Eerror\xa1GmessageX\x1dpath argument must be definedFstatusEerror
+  s>     \r\n
+  received frame(size=60; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  s>     0\r\n
+  s>     \r\n
+  abort: path argument must be defined!
+  [255]
+
+Unknown node is an error
+
+  $ sendhttpv2peer << EOF
+  > command filedata
+  >     nodes eval:[b'\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa']
+  >     path eval:b'a'
+  > EOF
+  creating http peer for wire protocol version 2
+  sending filedata command
+  s>     POST /api/exp-http-v2-0001/ro/filedata 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: 64\r\n
+  s>     host: $LOCALIP:$HGPORT\r\n (glob)
+  s>     user-agent: Mercurial debugwireproto\r\n
+  s>     \r\n
+  s>     8\x00\x00\x01\x00\x01\x01\x11\xa2Dargs\xa2Enodes\x81T\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaa\xaaDpathAaDnameHfiledata
+  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>     6b\r\n
+  s>     c\x00\x00\x01\x00\x02\x012
+  s>     \xa2Eerror\xa2Dargs\x81X(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaGmessageUunknown file node: %sFstatusEerror
+  s>     \r\n
+  received frame(size=99; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=eos)
+  s>     0\r\n
+  s>     \r\n
+  abort: unknown file node: aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa!
+  [255]
+
+Fetching a single revision returns just metadata by default
+
+  $ sendhttpv2peer << EOF
+  > command filedata
+  >     nodes eval:[b'\x9a\x38\x12\x29\x97\xb3\xac\x97\xbe\x2a\x9a\xa2\xe5\x56\x83\x83\x41\xfd\xf2\xcc']
+  >     path eval:b'a'
+  > EOF
+  creating http peer for wire protocol version 2
+  sending filedata command
+  s>     POST /api/exp-http-v2-0001/ro/filedata 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: 64\r\n
+  s>     host: $LOCALIP:$HGPORT\r\n (glob)
+  s>     user-agent: Mercurial debugwireproto\r\n
+  s>     \r\n
+  s>     8\x00\x00\x01\x00\x01\x01\x11\xa2Dargs\xa2Enodes\x81T\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xccDpathAaDnameHfiledata
+  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>     30\r\n
+  s>     (\x00\x00\x01\x00\x02\x001
+  s>     \xa1Jtotalitems\x01\xa1DnodeT\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xcc
+  s>     \r\n
+  received frame(size=40; 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: gen[
+    {
+      b'totalitems': 1
+    },
+    {
+      b'node': b'\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xcc'
+    }
+  ]
+
+Requesting parents works
+
+  $ sendhttpv2peer << EOF
+  > command filedata
+  >     nodes eval:[b'\x9a\x38\x12\x29\x97\xb3\xac\x97\xbe\x2a\x9a\xa2\xe5\x56\x83\x83\x41\xfd\xf2\xcc']
+  >     path eval:b'a'
+  >     fields eval:[b'parents']
+  > EOF
+  creating http peer for wire protocol version 2
+  sending filedata command
+  s>     POST /api/exp-http-v2-0001/ro/filedata 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: 80\r\n
+  s>     host: $LOCALIP:$HGPORT\r\n (glob)
+  s>     user-agent: Mercurial debugwireproto\r\n
+  s>     \r\n
+  s>     H\x00\x00\x01\x00\x01\x01\x11\xa2Dargs\xa3Ffields\x81GparentsEnodes\x81T\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xccDpathAaDnameHfiledata
+  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>     63\r\n
+  s>     [\x00\x00\x01\x00\x02\x001
+  s>     \xa1Jtotalitems\x01\xa2DnodeT\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xccGparents\x82T+N\xb0s\x19\xbf\xa0w\xa4\n
+  s>     /\x04\x916Y\xae\xf0\xdaB\xdaT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00
+  s>     \r\n
+  received frame(size=91; 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: gen[
+    {
+      b'totalitems': 1
+    },
+    {
+      b'node': b'\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xcc',
+      b'parents': [
+        b'+N\xb0s\x19\xbf\xa0w\xa4\n/\x04\x916Y\xae\xf0\xdaB\xda',
+        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
+      ]
+    }
+  ]
+
+Requesting revision data works
+
+  $ sendhttpv2peer << EOF
+  > command filedata
+  >     nodes eval:[b'\x9a\x38\x12\x29\x97\xb3\xac\x97\xbe\x2a\x9a\xa2\xe5\x56\x83\x83\x41\xfd\xf2\xcc']
+  >     path eval:b'a'
+  >     fields eval:[b'revision']
+  > EOF
+  creating http peer for wire protocol version 2
+  sending filedata command
+  s>     POST /api/exp-http-v2-0001/ro/filedata 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: 81\r\n
+  s>     host: $LOCALIP:$HGPORT\r\n (glob)
+  s>     user-agent: Mercurial debugwireproto\r\n
+  s>     \r\n
+  s>     I\x00\x00\x01\x00\x01\x01\x11\xa2Dargs\xa3Ffields\x81HrevisionEnodes\x81T\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xccDpathAaDnameHfiledata
+  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>     6e\r\n
+  s>     f\x00\x00\x01\x00\x02\x001
+  s>     \xa1Jtotalitems\x01\xa3MdeltabasenodeT+N\xb0s\x19\xbf\xa0w\xa4\n
+  s>     /\x04\x916Y\xae\xf0\xdaB\xdaIdeltasize\x0fDnodeT\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xccO\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x03a1\n
+  s>     \r\n
+  received frame(size=102; 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: gen[
+    {
+      b'totalitems': 1
+    },
+    {
+      b'deltabasenode': b'+N\xb0s\x19\xbf\xa0w\xa4\n/\x04\x916Y\xae\xf0\xdaB\xda',
+      b'deltasize': 15,
+      b'node': b'\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xcc'
+    },
+    b'\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x03a1\n'
+  ]
+
+Requesting multiple revisions works
+(first revision should be fulltext, subsequents are deltas)
+
+  $ sendhttpv2peer << EOF
+  > command filedata
+  >     nodes eval:['\x2b\x4e\xb0\x73\x19\xbf\xa0\x77\xa4\x0a\x2f\x04\x91\x36\x59\xae\xf0\xda\x42\xda', '\x9a\x38\x12\x29\x97\xb3\xac\x97\xbe\x2a\x9a\xa2\xe5\x56\x83\x83\x41\xfd\xf2\xcc']
+  >     path eval:b'a'
+  >     fields eval:[b'revision']
+  > EOF
+  creating http peer for wire protocol version 2
+  sending filedata command
+  s>     POST /api/exp-http-v2-0001/ro/filedata 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: 102\r\n
+  s>     host: $LOCALIP:$HGPORT\r\n (glob)
+  s>     user-agent: Mercurial debugwireproto\r\n
+  s>     \r\n
+  s>     ^\x00\x00\x01\x00\x01\x01\x11\xa2Dargs\xa3Ffields\x81HrevisionEnodes\x82T+N\xb0s\x19\xbf\xa0w\xa4\n
+  s>     /\x04\x916Y\xae\xf0\xdaB\xdaT\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xccDpathAaDnameHfiledata
+  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>     9b\r\n
+  s>     \x93\x00\x00\x01\x00\x02\x001
+  s>     \xa1Jtotalitems\x02\xa2DnodeT+N\xb0s\x19\xbf\xa0w\xa4\n
+  s>     /\x04\x916Y\xae\xf0\xdaB\xdaLrevisionsize\x03Ca0\n
+  s>     \xa3MdeltabasenodeT+N\xb0s\x19\xbf\xa0w\xa4\n
+  s>     /\x04\x916Y\xae\xf0\xdaB\xdaIdeltasize\x0fDnodeT\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xccO\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x03a1\n
+  s>     \r\n
+  received frame(size=147; 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: gen[
+    {
+      b'totalitems': 2
+    },
+    {
+      b'node': b'+N\xb0s\x19\xbf\xa0w\xa4\n/\x04\x916Y\xae\xf0\xdaB\xda',
+      b'revisionsize': 3
+    },
+    b'a0\n',
+    {
+      b'deltabasenode': b'+N\xb0s\x19\xbf\xa0w\xa4\n/\x04\x916Y\xae\xf0\xdaB\xda',
+      b'deltasize': 15,
+      b'node': b'\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xcc'
+    },
+    b'\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x03a1\n'
+  ]
+
+Revisions are sorted by DAG order, parents first
+
+  $ sendhttpv2peer << EOF
+  > command filedata
+  >     nodes eval:['\x9a\x38\x12\x29\x97\xb3\xac\x97\xbe\x2a\x9a\xa2\xe5\x56\x83\x83\x41\xfd\xf2\xcc', '\x2b\x4e\xb0\x73\x19\xbf\xa0\x77\xa4\x0a\x2f\x04\x91\x36\x59\xae\xf0\xda\x42\xda']
+  >     path eval:b'a'
+  >     fields eval:[b'revision']
+  > EOF
+  creating http peer for wire protocol version 2
+  sending filedata command
+  s>     POST /api/exp-http-v2-0001/ro/filedata 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: 102\r\n
+  s>     host: $LOCALIP:$HGPORT\r\n (glob)
+  s>     user-agent: Mercurial debugwireproto\r\n
+  s>     \r\n
+  s>     ^\x00\x00\x01\x00\x01\x01\x11\xa2Dargs\xa3Ffields\x81HrevisionEnodes\x82T\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xccT+N\xb0s\x19\xbf\xa0w\xa4\n
+  s>     /\x04\x916Y\xae\xf0\xdaB\xdaDpathAaDnameHfiledata
+  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>     9b\r\n
+  s>     \x93\x00\x00\x01\x00\x02\x001
+  s>     \xa1Jtotalitems\x02\xa2DnodeT+N\xb0s\x19\xbf\xa0w\xa4\n
+  s>     /\x04\x916Y\xae\xf0\xdaB\xdaLrevisionsize\x03Ca0\n
+  s>     \xa3MdeltabasenodeT+N\xb0s\x19\xbf\xa0w\xa4\n
+  s>     /\x04\x916Y\xae\xf0\xdaB\xdaIdeltasize\x0fDnodeT\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xccO\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x03a1\n
+  s>     \r\n
+  received frame(size=147; 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: gen[
+    {
+      b'totalitems': 2
+    },
+    {
+      b'node': b'+N\xb0s\x19\xbf\xa0w\xa4\n/\x04\x916Y\xae\xf0\xdaB\xda',
+      b'revisionsize': 3
+    },
+    b'a0\n',
+    {
+      b'deltabasenode': b'+N\xb0s\x19\xbf\xa0w\xa4\n/\x04\x916Y\xae\xf0\xdaB\xda',
+      b'deltasize': 15,
+      b'node': b'\x9a8\x12)\x97\xb3\xac\x97\xbe*\x9a\xa2\xe5V\x83\x83A\xfd\xf2\xcc'
+    },
+    b'\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x03a1\n'
+  ]
+
+Requesting parents and revision data works
+
+  $ sendhttpv2peer << EOF
+  > command filedata
+  >     nodes eval:['\x08\x79\x34\x5e\x39\x37\x72\x29\x63\x4b\x42\x0c\x63\x94\x54\x15\x67\x26\xc6\xb6']
+  >     path eval:b'a'
+  >     fields eval:[b'parents', b'revision']
+  > EOF
+  creating http peer for wire protocol version 2
+  sending filedata command
+  s>     POST /api/exp-http-v2-0001/ro/filedata 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: 89\r\n
+  s>     host: $LOCALIP:$HGPORT\r\n (glob)
+  s>     user-agent: Mercurial debugwireproto\r\n
+  s>     \r\n
+  s>     Q\x00\x00\x01\x00\x01\x01\x11\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81T\x08y4^97r)cKB\x0cc\x94T\x15g&\xc6\xb6DpathAaDnameHfiledata
+  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>     a1\r\n
+  s>     \x99\x00\x00\x01\x00\x02\x001
+  s>     \xa1Jtotalitems\x01\xa4MdeltabasenodeT+N\xb0s\x19\xbf\xa0w\xa4\n
+  s>     /\x04\x916Y\xae\xf0\xdaB\xdaIdeltasize\x0fDnodeT\x08y4^97r)cKB\x0cc\x94T\x15g&\xc6\xb6Gparents\x82T+N\xb0s\x19\xbf\xa0w\xa4\n
+  s>     /\x04\x916Y\xae\xf0\xdaB\xdaT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00O\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x03a2\n
+  s>     \r\n
+  received frame(size=153; 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: gen[
+    {
+      b'totalitems': 1
+    },
+    {
+      b'deltabasenode': b'+N\xb0s\x19\xbf\xa0w\xa4\n/\x04\x916Y\xae\xf0\xdaB\xda',
+      b'deltasize': 15,
+      b'node': b'\x08y4^97r)cKB\x0cc\x94T\x15g&\xc6\xb6',
+      b'parents': [
+        b'+N\xb0s\x19\xbf\xa0w\xa4\n/\x04\x916Y\xae\xf0\xdaB\xda',
+        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
+      ]
+    },
+    b'\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x03a2\n'
+  ]
+
+  $ cat error.log

mercurial/help/internals/wireprotocolv2.txt

@@ -196,6 +196,79 b' TODO support depth limiting'
 TODO support hgtagsfnodes cache / tags data
 TODO support branch heads cache
 
+filedata
+--------
+
+Obtain various data related to an individual tracked file.
+
+The command accepts the following arguments:
+
+fields
+   (set of bytestring) Which data associated with a file to fetch.
+   The following values are recognized:
+
+   parents
+      Parent nodes for the revision.
+
+   revision
+      The raw revision data for a file.
+
+nodes
+   (array of bytestrings) File nodes whose data to retrieve.
+
+path
+   (bytestring) Path of the tracked file whose data to retrieve.
+
+TODO allow specifying revisions via alternate means (such as from
+changeset revisions or ranges)
+
+The response bytestream starts with a CBOR map describing the data that
+follows. It has the following bytestream keys:
+
+totalitems
+   (unsigned integer) Total number of file revisions whose data is
+   being returned.
+
+Following the header map is a series of 0 or more CBOR values. The first
+value is always a map describing a file revision. If this map has the
+``deltasize`` or ``revisionsize`` keys, a bytestring containing the delta
+or revision, respectively, will immediately follow the map. Otherwise
+the next value will be a map describing the next file revision.
+
+Each map has the following bytestring keys:
+
+node
+   (bytestring) The node of the file revision whose data is represented.
+
+deltabasenode
+   (bytestring) Node of the file revision the following delta is against.
+
+   Only present if the ``revision`` field is requested and delta data
+   follows this map.
+
+deltasize
+   (unsigned integer) The size of the delta data that follows this map.
+
+   Only present if the ``revision`` field is requested and delta data
+   follows this map.
+
+parents
+   (array of bytestring) The nodes of the parents of this file revision.
+
+   Only present if the ``parents`` field is requested.
+
+revisionsize
+   (unsigned integer) The size of the fulltext revision data that follows
+   this map.
+
+   Only present if the ``revision`` field is requested and fulltext revision
+   data follows this map.
+
+When ``revision`` data is requested, the server chooses to emit either fulltext
+revision data or a delta. What the server decides can be inferred by looking
+for the presence of the ``deltasize`` or ``revisionsize`` keys in the map.
+Servers MUST NOT define both keys.
+
 heads
 -----
 

mercurial/wireprotov2server.py

@@ -10,6 +10,7 b' import contextlib'
 
 from .i18n import _
 from .node import (
+    hex,
     nullid,
     nullrev,
 )
@@ -648,6 +649,112 b' def changesetdata(repo, proto, noderange'
                 b'bookmarks': sorted(marks),
             }
 
+class FileAccessError(Exception):
+    """Represents an error accessing a specific file."""
+
+    def __init__(self, path, msg, args):
+        self.path = path
+        self.msg = msg
+        self.args = args
+
+def getfilestore(repo, proto, path):
+    """Obtain a file storage object for use with wire protocol.
+
+    Exists as a standalone function so extensions can monkeypatch to add
+    access control.
+    """
+    # This seems to work even if the file doesn't exist. So catch
+    # "empty" files and return an error.
+    fl = repo.file(path)
+
+    if not len(fl):
+        raise FileAccessError(path, 'unknown file: %s', (path,))
+
+    return fl
+
+@wireprotocommand('filedata',
+                  args={
+                      'nodes': [b'0123456...'],
+                      'fields': [b'parents', b'revision'],
+                      'path': b'foo.txt',
+                  },
+                  permission='pull')
+def filedata(repo, proto, nodes=None, fields=None, path=None):
+    fields = fields or set()
+
+    if nodes is None:
+        raise error.WireprotoCommandError('nodes argument must be defined')
+
+    if path is None:
+        raise error.WireprotoCommandError('path argument must be defined')
+
+    try:
+        # Extensions may wish to access the protocol handler.
+        store = getfilestore(repo, proto, path)
+    except FileAccessError as e:
+        raise error.WireprotoCommandError(e.msg, e.args)
+
+    # Validate requested nodes.
+    for node in nodes:
+        try:
+            store.rev(node)
+        except error.LookupError:
+            raise error.WireprotoCommandError('unknown file node: %s',
+                                              (hex(node),))
+
+    revs, requests = builddeltarequests(store, nodes)
+
+    yield {
+        b'totalitems': len(revs),
+    }
+
+    if b'revision' in fields:
+        deltas = store.emitrevisiondeltas(requests)
+    else:
+        deltas = None
+
+    for rev in revs:
+        node = store.node(rev)
+
+        if deltas is not None:
+            delta = next(deltas)
+        else:
+            delta = None
+
+        d = {
+            b'node': node,
+        }
+
+        if b'parents' in fields:
+            d[b'parents'] = store.parents(node)
+
+        if b'revision' in fields:
+            assert delta is not None
+            assert delta.flags == 0
+            assert d[b'node'] == delta.node
+
+            if delta.revision is not None:
+                revisiondata = delta.revision
+                d[b'revisionsize'] = len(revisiondata)
+            else:
+                d[b'deltabasenode'] = delta.basenode
+                revisiondata = delta.delta
+                d[b'deltasize'] = len(revisiondata)
+        else:
+            revisiondata = None
+
+        yield d
+
+        if revisiondata is not None:
+            yield revisiondata
+
+    if deltas is not None:
+        try:
+            next(deltas)
+            raise error.ProgrammingError('should not have more deltas')
+        except GeneratorExit:
+            pass
+
 @wireprotocommand('heads',
                   args={
                       'publiconly': False,

tests/test-http-protocol.t

@@ -313,7 +313,7 b' Client with HTTPv2 enabled automatically'
   s>     Content-Type: application/mercurial-cbor\r\n
   s>     Content-Length: *\r\n (glob)
   s>     \r\n
-  s>     \xa3GapibaseDapi/Dapis\xa1Pexp-http-v2-0001\xa4Hcommands\xa9Ibranchmap\xa2Dargs\xa0Kpermissions\x81DpullLcapabilities\xa2Dargs\xa0Kpermissions\x81DpullMchangesetdata\xa2Dargs\xa3Ffields\xd9\x01\x02\x82GparentsHrevisionInoderange\x82\x81J0123456...\x81Iabcdef...Enodes\x81J0123456...Kpermissions\x81DpullEheads\xa2Dargs\xa1Jpubliconly\xf4Kpermissions\x81DpullEknown\xa2Dargs\xa1Enodes\x81HdeadbeefKpermissions\x81DpullHlistkeys\xa2Dargs\xa1InamespaceBnsKpermissions\x81DpullFlookup\xa2Dargs\xa1CkeyCfooKpermissions\x81DpullLmanifestdata\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81J0123456...Dtree@Kpermissions\x81DpullGpushkey\xa2Dargs\xa4CkeyCkeyInamespaceBnsCnewCnewColdColdKpermissions\x81DpushKcompression\x81\xa1DnameDzlibQframingmediatypes\x81X&application/mercurial-exp-framing-0005Nrawrepoformats\x82LgeneraldeltaHrevlogv1Nv1capabilitiesY\x01\xc5batch branchmap $USUAL_BUNDLE2_CAPS_SERVER$ changegroupsubset compression=$BUNDLE2_COMPRESSIONS$ getbundle httpheader=1024 httpmediatype=0.1rx,0.1tx,0.2tx known lookup pushkey streamreqs=generaldelta,revlogv1 unbundle=HG10GZ,HG10BZ,HG10UN unbundlehash
+  s>     \xa3GapibaseDapi/Dapis\xa1Pexp-http-v2-0001\xa4Hcommands\xaaIbranchmap\xa2Dargs\xa0Kpermissions\x81DpullLcapabilities\xa2Dargs\xa0Kpermissions\x81DpullMchangesetdata\xa2Dargs\xa3Ffields\xd9\x01\x02\x82GparentsHrevisionInoderange\x82\x81J0123456...\x81Iabcdef...Enodes\x81J0123456...Kpermissions\x81DpullHfiledata\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81J0123456...DpathGfoo.txtKpermissions\x81DpullEheads\xa2Dargs\xa1Jpubliconly\xf4Kpermissions\x81DpullEknown\xa2Dargs\xa1Enodes\x81HdeadbeefKpermissions\x81DpullHlistkeys\xa2Dargs\xa1InamespaceBnsKpermissions\x81DpullFlookup\xa2Dargs\xa1CkeyCfooKpermissions\x81DpullLmanifestdata\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81J0123456...Dtree@Kpermissions\x81DpullGpushkey\xa2Dargs\xa4CkeyCkeyInamespaceBnsCnewCnewColdColdKpermissions\x81DpushKcompression\x81\xa1DnameDzlibQframingmediatypes\x81X&application/mercurial-exp-framing-0005Nrawrepoformats\x82LgeneraldeltaHrevlogv1Nv1capabilitiesY\x01\xc5batch branchmap $USUAL_BUNDLE2_CAPS_SERVER$ changegroupsubset compression=$BUNDLE2_COMPRESSIONS$ getbundle httpheader=1024 httpmediatype=0.1rx,0.1tx,0.2tx known lookup pushkey streamreqs=generaldelta,revlogv1 unbundle=HG10GZ,HG10BZ,HG10UN unbundlehash
   sending heads command
   s>     POST /api/exp-http-v2-0001/ro/heads HTTP/1.1\r\n
   s>     Accept-Encoding: identity\r\n

tests/test-wireproto-command-capabilities.t

@@ -212,7 +212,7 b' Request for HTTPv2 service returns infor'
   s>     Content-Type: application/mercurial-cbor\r\n
   s>     Content-Length: *\r\n (glob)
   s>     \r\n
-  s>     \xa3GapibaseDapi/Dapis\xa1Pexp-http-v2-0001\xa4Hcommands\xa9Ibranchmap\xa2Dargs\xa0Kpermissions\x81DpullLcapabilities\xa2Dargs\xa0Kpermissions\x81DpullMchangesetdata\xa2Dargs\xa3Ffields\xd9\x01\x02\x82GparentsHrevisionInoderange\x82\x81J0123456...\x81Iabcdef...Enodes\x81J0123456...Kpermissions\x81DpullEheads\xa2Dargs\xa1Jpubliconly\xf4Kpermissions\x81DpullEknown\xa2Dargs\xa1Enodes\x81HdeadbeefKpermissions\x81DpullHlistkeys\xa2Dargs\xa1InamespaceBnsKpermissions\x81DpullFlookup\xa2Dargs\xa1CkeyCfooKpermissions\x81DpullLmanifestdata\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81J0123456...Dtree@Kpermissions\x81DpullGpushkey\xa2Dargs\xa4CkeyCkeyInamespaceBnsCnewCnewColdColdKpermissions\x81DpushKcompression\x81\xa1DnameDzlibQframingmediatypes\x81X&application/mercurial-exp-framing-0005Nrawrepoformats\x82LgeneraldeltaHrevlogv1Nv1capabilitiesY\x01\xc5batch branchmap $USUAL_BUNDLE2_CAPS_SERVER$ changegroupsubset compression=$BUNDLE2_COMPRESSIONS$ getbundle httpheader=1024 httpmediatype=0.1rx,0.1tx,0.2tx known lookup pushkey streamreqs=generaldelta,revlogv1 unbundle=HG10GZ,HG10BZ,HG10UN unbundlehash
+  s>     \xa3GapibaseDapi/Dapis\xa1Pexp-http-v2-0001\xa4Hcommands\xaaIbranchmap\xa2Dargs\xa0Kpermissions\x81DpullLcapabilities\xa2Dargs\xa0Kpermissions\x81DpullMchangesetdata\xa2Dargs\xa3Ffields\xd9\x01\x02\x82GparentsHrevisionInoderange\x82\x81J0123456...\x81Iabcdef...Enodes\x81J0123456...Kpermissions\x81DpullHfiledata\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81J0123456...DpathGfoo.txtKpermissions\x81DpullEheads\xa2Dargs\xa1Jpubliconly\xf4Kpermissions\x81DpullEknown\xa2Dargs\xa1Enodes\x81HdeadbeefKpermissions\x81DpullHlistkeys\xa2Dargs\xa1InamespaceBnsKpermissions\x81DpullFlookup\xa2Dargs\xa1CkeyCfooKpermissions\x81DpullLmanifestdata\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81J0123456...Dtree@Kpermissions\x81DpullGpushkey\xa2Dargs\xa4CkeyCkeyInamespaceBnsCnewCnewColdColdKpermissions\x81DpushKcompression\x81\xa1DnameDzlibQframingmediatypes\x81X&application/mercurial-exp-framing-0005Nrawrepoformats\x82LgeneraldeltaHrevlogv1Nv1capabilitiesY\x01\xc5batch branchmap $USUAL_BUNDLE2_CAPS_SERVER$ changegroupsubset compression=$BUNDLE2_COMPRESSIONS$ getbundle httpheader=1024 httpmediatype=0.1rx,0.1tx,0.2tx known lookup pushkey streamreqs=generaldelta,revlogv1 unbundle=HG10GZ,HG10BZ,HG10UN unbundlehash
   cbor> {
     b'apibase': b'api/',
     b'apis': {
@@ -252,6 +252,21 b' Request for HTTPv2 service returns infor'
               b'pull'
             ]
           },
+          b'filedata': {
+            b'args': {
+              b'fields': [
+                b'parents',
+                b'revision'
+              ],
+              b'nodes': [
+                b'0123456...'
+              ],
+              b'path': b'foo.txt'
+            },
+            b'permissions': [
+              b'pull'
+            ]
+          },
           b'heads': {
             b'args': {
               b'publiconly': False
@@ -352,7 +367,7 b' capabilities command returns expected in'
   s>     Content-Type: application/mercurial-cbor\r\n
   s>     Content-Length: *\r\n (glob)
   s>     \r\n
-  s>     \xa3GapibaseDapi/Dapis\xa1Pexp-http-v2-0001\xa4Hcommands\xa9Ibranchmap\xa2Dargs\xa0Kpermissions\x81DpullLcapabilities\xa2Dargs\xa0Kpermissions\x81DpullMchangesetdata\xa2Dargs\xa3Ffields\xd9\x01\x02\x82GparentsHrevisionInoderange\x82\x81J0123456...\x81Iabcdef...Enodes\x81J0123456...Kpermissions\x81DpullEheads\xa2Dargs\xa1Jpubliconly\xf4Kpermissions\x81DpullEknown\xa2Dargs\xa1Enodes\x81HdeadbeefKpermissions\x81DpullHlistkeys\xa2Dargs\xa1InamespaceBnsKpermissions\x81DpullFlookup\xa2Dargs\xa1CkeyCfooKpermissions\x81DpullLmanifestdata\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81J0123456...Dtree@Kpermissions\x81DpullGpushkey\xa2Dargs\xa4CkeyCkeyInamespaceBnsCnewCnewColdColdKpermissions\x81DpushKcompression\x81\xa1DnameDzlibQframingmediatypes\x81X&application/mercurial-exp-framing-0005Nrawrepoformats\x82LgeneraldeltaHrevlogv1Nv1capabilitiesY\x01\xc5batch branchmap $USUAL_BUNDLE2_CAPS_SERVER$ changegroupsubset compression=$BUNDLE2_COMPRESSIONS$ getbundle httpheader=1024 httpmediatype=0.1rx,0.1tx,0.2tx known lookup pushkey streamreqs=generaldelta,revlogv1 unbundle=HG10GZ,HG10BZ,HG10UN unbundlehash
+  s>     \xa3GapibaseDapi/Dapis\xa1Pexp-http-v2-0001\xa4Hcommands\xaaIbranchmap\xa2Dargs\xa0Kpermissions\x81DpullLcapabilities\xa2Dargs\xa0Kpermissions\x81DpullMchangesetdata\xa2Dargs\xa3Ffields\xd9\x01\x02\x82GparentsHrevisionInoderange\x82\x81J0123456...\x81Iabcdef...Enodes\x81J0123456...Kpermissions\x81DpullHfiledata\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81J0123456...DpathGfoo.txtKpermissions\x81DpullEheads\xa2Dargs\xa1Jpubliconly\xf4Kpermissions\x81DpullEknown\xa2Dargs\xa1Enodes\x81HdeadbeefKpermissions\x81DpullHlistkeys\xa2Dargs\xa1InamespaceBnsKpermissions\x81DpullFlookup\xa2Dargs\xa1CkeyCfooKpermissions\x81DpullLmanifestdata\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81J0123456...Dtree@Kpermissions\x81DpullGpushkey\xa2Dargs\xa4CkeyCkeyInamespaceBnsCnewCnewColdColdKpermissions\x81DpushKcompression\x81\xa1DnameDzlibQframingmediatypes\x81X&application/mercurial-exp-framing-0005Nrawrepoformats\x82LgeneraldeltaHrevlogv1Nv1capabilitiesY\x01\xc5batch branchmap $USUAL_BUNDLE2_CAPS_SERVER$ changegroupsubset compression=$BUNDLE2_COMPRESSIONS$ getbundle httpheader=1024 httpmediatype=0.1rx,0.1tx,0.2tx known lookup pushkey streamreqs=generaldelta,revlogv1 unbundle=HG10GZ,HG10BZ,HG10UN unbundlehash
   sending capabilities command
   s>     POST /api/exp-http-v2-0001/ro/capabilities HTTP/1.1\r\n
   s>     Accept-Encoding: identity\r\n
@@ -375,11 +390,11 b' capabilities command returns expected in'
   s>     \xa1FstatusBok
   s>     \r\n
   received frame(size=11; request=1; stream=2; streamflags=stream-begin; type=command-response; flags=continuation)
-  s>     29a\r\n
-  s>     \x92\x02\x00\x01\x00\x02\x001
-  s>     \xa4Hcommands\xa9Ibranchmap\xa2Dargs\xa0Kpermissions\x81DpullLcapabilities\xa2Dargs\xa0Kpermissions\x81DpullMchangesetdata\xa2Dargs\xa3Ffields\xd9\x01\x02\x82GparentsHrevisionInoderange\x82\x81J0123456...\x81Iabcdef...Enodes\x81J0123456...Kpermissions\x81DpullEheads\xa2Dargs\xa1Jpubliconly\xf4Kpermissions\x81DpullEknown\xa2Dargs\xa1Enodes\x81HdeadbeefKpermissions\x81DpullHlistkeys\xa2Dargs\xa1InamespaceBnsKpermissions\x81DpullFlookup\xa2Dargs\xa1CkeyCfooKpermissions\x81DpullLmanifestdata\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81J0123456...Dtree@Kpermissions\x81DpullGpushkey\xa2Dargs\xa4CkeyCkeyInamespaceBnsCnewCnewColdColdKpermissions\x81DpushKcompression\x81\xa1DnameDzlibQframingmediatypes\x81X&application/mercurial-exp-framing-0005Nrawrepoformats\x82LgeneraldeltaHrevlogv1
+  s>     2f4\r\n
+  s>     \xec\x02\x00\x01\x00\x02\x001
+  s>     \xa4Hcommands\xaaIbranchmap\xa2Dargs\xa0Kpermissions\x81DpullLcapabilities\xa2Dargs\xa0Kpermissions\x81DpullMchangesetdata\xa2Dargs\xa3Ffields\xd9\x01\x02\x82GparentsHrevisionInoderange\x82\x81J0123456...\x81Iabcdef...Enodes\x81J0123456...Kpermissions\x81DpullHfiledata\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81J0123456...DpathGfoo.txtKpermissions\x81DpullEheads\xa2Dargs\xa1Jpubliconly\xf4Kpermissions\x81DpullEknown\xa2Dargs\xa1Enodes\x81HdeadbeefKpermissions\x81DpullHlistkeys\xa2Dargs\xa1InamespaceBnsKpermissions\x81DpullFlookup\xa2Dargs\xa1CkeyCfooKpermissions\x81DpullLmanifestdata\xa2Dargs\xa3Ffields\x82GparentsHrevisionEnodes\x81J0123456...Dtree@Kpermissions\x81DpullGpushkey\xa2Dargs\xa4CkeyCkeyInamespaceBnsCnewCnewColdColdKpermissions\x81DpushKcompression\x81\xa1DnameDzlibQframingmediatypes\x81X&application/mercurial-exp-framing-0005Nrawrepoformats\x82LgeneraldeltaHrevlogv1
   s>     \r\n
-  received frame(size=658; request=1; stream=2; streamflags=; type=command-response; flags=continuation)
+  received frame(size=748; 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
@@ -423,6 +438,21 b' capabilities command returns expected in'
             b'pull'
           ]
         },
+        b'filedata': {
+          b'args': {
+            b'fields': [
+              b'parents',
+              b'revision'
+            ],
+            b'nodes': [
+              b'0123456...'
+            ],
+            b'path': b'foo.txt'
+          },
+          b'permissions': [
+            b'pull'
+          ]
+        },
         b'heads': {
           b'args': {
             b'publiconly': False