diff mercurial/wireprotoframing.py @ 40024:86b22a4cfab1

wireprotov2: client support for advertising redirect targets

With the server now able to emit a redirect target descriptor, we can
start to teach the client to recognize it.

This commit implements support for filtering the advertised
redirect targets against supported features and for advertising
compatible redirect targets as part of command requests. It also
adds the minimal boilerplate required to fail when a content
redirect is seen.

The server doesn't yet do anything with the advertised redirect
targets. And the client can't yet follow redirects if it did. But
at least we're putting bytes on the wire.

Differential Revision: https://phab.mercurial-scm.org/D4776

--- a/mercurial/wireprotoframing.py	Wed Sep 26 17:46:48 2018 -0700
+++ b/mercurial/wireprotoframing.py	Wed Sep 26 15:02:19 2018 -0700
@@ -280,7 +280,8 @@
                  payload)
 
 def createcommandframes(stream, requestid, cmd, args, datafh=None,
-                        maxframesize=DEFAULT_MAX_FRAME_SIZE):
+                        maxframesize=DEFAULT_MAX_FRAME_SIZE,
+                        redirect=None):
     """Create frames necessary to transmit a request to run a command.
 
     This is a generator of bytearrays. Each item represents a frame
@@ -290,6 +291,9 @@
     if args:
         data[b'args'] = args
 
+    if redirect:
+        data[b'redirect'] = redirect
+
     data = b''.join(cborutil.streamencode(data))
 
     offset = 0
@@ -1135,11 +1139,12 @@
 class commandrequest(object):
     """Represents a request to run a command."""
 
-    def __init__(self, requestid, name, args, datafh=None):
+    def __init__(self, requestid, name, args, datafh=None, redirect=None):
         self.requestid = requestid
         self.name = name
         self.args = args
         self.datafh = datafh
+        self.redirect = redirect
         self.state = 'pending'
 
 class clientreactor(object):
@@ -1178,7 +1183,7 @@
         self._activerequests = {}
         self._incomingstreams = {}
 
-    def callcommand(self, name, args, datafh=None):
+    def callcommand(self, name, args, datafh=None, redirect=None):
         """Request that a command be executed.
 
         Receives the command name, a dict of arguments to pass to the command,
@@ -1192,7 +1197,8 @@
         requestid = self._nextrequestid
         self._nextrequestid += 2
 
-        request = commandrequest(requestid, name, args, datafh=datafh)
+        request = commandrequest(requestid, name, args, datafh=datafh,
+                                 redirect=redirect)
 
         if self._buffersends:
             self._pendingrequests.append(request)
@@ -1256,7 +1262,8 @@
                                   request.requestid,
                                   request.name,
                                   request.args,
-                                  request.datafh)
+                                  datafh=request.datafh,
+                                  redirect=request.redirect)
 
         for frame in res:
             yield frame