Bug 1752444 - Part 1: Add {Parent,Child}Impl attributes to ipdl, r=ip…

…c-reviewers,mccr8

These attributes replace the previous direct_call.py table which
specified how to locate the concrete implementation of a protocol and
whether it should use a virtual implementation or not.

They work by specifying the concrete type for an actor, and disabling
the automatic inclusion of the implementation's header file, which can
be included explicitly with an `include "";` statement. This allows
customizing both the name and include path of the concrete
implementation of an interface.

Differential Revision: https://phabricator.services.mozilla.com/D137226

ipc/ipdl/ipdl/ast.py

@@ -61,18 +61,21 @@ def visitInclude(self, inc):
     def visitStructDecl(self, struct):
         for f in struct.fields:
             f.accept(self)
+        for a in struct.attributes.values():
+            a.accept(self)
 
     def visitStructField(self, field):
         field.typespec.accept(self)
 
     def visitUnionDecl(self, union):
         for t in union.components:
             t.accept(self)
+        for a in union.attributes.values():
+            a.accept(self)
 
     def visitUsingStmt(self, using):
         for a in using.attributes.values():
             a.accept(self)
-        pass
 
     def visitProtocol(self, p):
         for namespace in p.namespaces:
@@ -83,6 +86,8 @@ def visitProtocol(self, p):
             managed.accept(self)
         for msgDecl in p.messageDecls:
             msgDecl.accept(self)
+        for a in p.attributes.values():
+            a.accept(self)
 
     def visitNamespace(self, ns):
         pass
@@ -98,18 +103,26 @@ def visitMessageDecl(self, md):
             inParam.accept(self)
         for outParam in md.outParams:
             outParam.accept(self)
+        for a in md.attributes.values():
+            a.accept(self)
 
     def visitParam(self, decl):
-        pass
+        for a in decl.attributes.values():
+            a.accept(self)
 
     def visitTypeSpec(self, ts):
         pass
 
     def visitAttribute(self, a):
+        if isinstance(a.value, Node):
+            a.value.accept(self)
+
+    def visitStringLiteral(self, sl):
         pass
 
     def visitDecl(self, d):
-        pass
+        for a in d.attributes.values():
+            a.accept(self)
 
 
 class Loc:
@@ -303,6 +316,13 @@ def nestedUpTo(self):
 
         return NESTED_ATTR_MAP.get(self.attributes["NestedUpTo"].value, NOT_NESTED)
 
+    def implAttribute(self, side):
+        assert side in ("parent", "child")
+        attr = self.attributes.get(side.capitalize() + "Impl")
+        if attr is not None:
+            return attr.value
+        return None
+
 
 class StructField(Node):
     def __init__(self, loc, type, name):
@@ -402,6 +422,15 @@ def __init__(self, loc, name, value):
         self.value = value
 
 
+class StringLiteral(Node):
+    def __init__(self, loc, value):
+        Node.__init__(self, loc)
+        self.value = value
+
+    def __str__(self):
+        return '"%s"' % self.value
+
+
 class QualifiedId:  # FIXME inherit from node?
     def __init__(self, loc, baseid, quals=[]):
         assert isinstance(baseid, str)