QPID-979: added access to enums through the session so that symbolic constants can be used rather than hard coded ones; also added default loading of the spec

git-svn-id: https://svn.apache.org/repos/asf/incubator/qpid/trunk/qpid@654618 13f79535-47bb-0310-9956-ffa450edef68

5 files changed, 61 insertions, 17 deletions

diff --git a/python/qpid/connection.py b/python/qpid/connection.py
index dc72cd9cb8..39f882e9c3 100644
--- a/python/qpid/connection.py
+++ b/python/qpid/connection.py
@@ -25,7 +25,8 @@ from assembler import Assembler, Segment
 from codec010 import StringCodec
 from session import Session
 from invoker import Invoker
-from spec010 import Control, Command
+from spec010 import Control, Command, load
+from spec import default
 from exceptions import *
 from logging import getLogger
 import delegates
@@ -44,8 +45,10 @@ def server(*args):
 
 class Connection(Assembler):
 
-  def __init__(self, sock, spec, delegate=client):
+  def __init__(self, sock, spec=None, delegate=client):
     Assembler.__init__(self, sock)
+    if spec == None:
+      spec = load(default())
     self.spec = spec
     self.track = self.spec["track"]
 
@@ -162,9 +165,9 @@ class Channel(Invoker):
   def resolve_method(self, name):
     inst = self.connection.spec.instructions.get(name)
     if inst is not None and isinstance(inst, Control):
-      return inst
+      return self.METHOD, inst
     else:
-      return None
+      return self.ERROR, None
 
   def invoke(self, type, args, kwargs):
     ctl = type.new(args, kwargs)
diff --git a/python/qpid/invoker.py b/python/qpid/invoker.py
index 9e6f6943d8..2d9e45179e 100644
--- a/python/qpid/invoker.py
+++ b/python/qpid/invoker.py
@@ -17,16 +17,26 @@
 # under the License.
 #
 
+# TODO: need a better naming for this class now that it does the value
+# stuff
 class Invoker:
 
-  def resolve_method(self, name):
-    pass
-
-  def __getattr__(self, name):
-    resolved = self.resolve_method(name)
-    if resolved == None:
-      raise AttributeError("%s instance has no attribute '%s'" %
-                           (self.__class__.__name__, name))
+  def METHOD(self, name, resolved):
     method = lambda *args, **kwargs: self.invoke(resolved, args, kwargs)
     self.__dict__[name] = method
     return method
+
+  def VALUE(self, name, resolved):
+    self.__dict__[name] = resolved
+    return resolved
+
+  def ERROR(self, name, resolved):
+    raise AttributeError("%s instance has no attribute '%s'" %
+                         (self.__class__.__name__, name))
+
+  def resolve_method(self, name):
+    return ERROR, None
+
+  def __getattr__(self, name):
+    disp, resolved = self.resolve_method(name)
+    return disp(name, resolved)
diff --git a/python/qpid/session.py b/python/qpid/session.py
index 11249ca435..f8ac98b96e 100644
--- a/python/qpid/session.py
+++ b/python/qpid/session.py
@@ -112,15 +112,17 @@ class Session(Invoker):
   def resolve_method(self, name):
     cmd = self.spec.instructions.get(name)
     if cmd is not None and cmd.track == self.spec["track.command"].value:
-      return cmd
+      return self.METHOD, cmd
     else:
       # XXX
       for st in self.spec.structs.values():
         if st.name == name:
-          return st
-      if self.spec.structs_by_name.has_key(name):  
-        return self.spec.structs_by_name[name]
-      return None
+          return self.METHOD, st
+      if self.spec.structs_by_name.has_key(name):
+        return self.METHOD, self.spec.structs_by_name[name]
+      if self.spec.enums.has_key(name):
+        return self.VALUE, self.spec.enums[name]
+      return self.ERROR, None
 
   def invoke(self, type, args, kwargs):
     # XXX
diff --git a/python/qpid/spec.py b/python/qpid/spec.py
index 64a14b0f61..152763b762 100644
--- a/python/qpid/spec.py
+++ b/python/qpid/spec.py
@@ -31,6 +31,19 @@ situations.
 
 import os, mllib, spec08, spec010
 
+def default():
+  try:
+    specfile = os.environ["AMQP_SPEC"]
+    return specfile
+  except KeyError:
+    try:
+      from AMQP_SPEC import location as specfile
+      return specfile
+    except ImportError:
+      raise Exception("unable to locate the amqp specification, please set "
+                      "the AMQP_SPEC environment variable or supply a "
+                      "configured AMQP_SPEC.py")
+
 def load(specfile, *errata):
   for name in (specfile,) + errata:
     if not os.path.exists(name):
diff --git a/python/qpid/spec010.py b/python/qpid/spec010.py
index 1668729876..fb625eab65 100644
--- a/python/qpid/spec010.py
+++ b/python/qpid/spec010.py
@@ -166,6 +166,15 @@ class Domain(Type, Lookup):
   def decode(self, codec):
     return self.type.decode(codec)
 
+class Enum:
+
+  def __init__(self, name):
+    self.name = name
+
+  def __repr__(self):
+    return "%s(%s)" % (self.name, ", ".join([k for k in self.__dict__.keys()
+                                             if k != "name"]))
+
 class Choice(Named, Node):
 
   def __init__(self, name, value, children):
@@ -177,6 +186,12 @@ class Choice(Named, Node):
     Named.register(self, node)
     node.choices[self.value] = self
     Node.register(self)
+    try:
+      enum = node.spec.enums[node.name]
+    except KeyError:
+      enum = Enum(node.name)
+      node.spec.enums[node.name] = enum
+    setattr(enum, self.name, self.value)
 
 class Composite(Type, Coded):
 
@@ -450,6 +465,7 @@ class Spec(Node):
     self.commands = {}
     self.structs = {}
     self.structs_by_name = {}
+    self.enums = {}
 
   def encoding(self, klass):
     if Spec.ENCODINGS.has_key(klass):