qapi: Top-level type reference for command definitions

index 02ad668..3a64769 100644
@@ -76,12 +76,18 @@ def parse(tokens):
         return tokens[0], tokens[1:]
 
 def evaluate(string):
-    return parse(map(lambda x: x, tokenize(string)))[0]
+    expr_eval = parse(map(lambda x: x, tokenize(string)))[0]
+
+    if expr_eval.has_key('enum'):
+        add_enum(expr_eval['enum'])
+    elif expr_eval.has_key('union'):
+        add_enum('%sKind' % expr_eval['union'])
+
+    return expr_eval
 
 def parse_schema(fp):
     exprs = []
     expr = ''
-    expr_eval = None
 
     for line in fp:
         if line.startswith('#') or line == '\n':

@@ -90,23 +96,13 @@ def parse_schema(fp):
         if line.startswith(' '):
             expr += line
         elif expr:
-            expr_eval = evaluate(expr)
-            if expr_eval.has_key('enum'):
-                add_enum(expr_eval['enum'])
-            elif expr_eval.has_key('union'):
-                add_enum('%sKind' % expr_eval['union'])
-            exprs.append(expr_eval)
+            exprs.append(evaluate(expr))
             expr = line
         else:
             expr += line
 
     if expr:
-        expr_eval = evaluate(expr)
-        if expr_eval.has_key('enum'):
-            add_enum(expr_eval['enum'])
-        elif expr_eval.has_key('union'):
-            add_enum('%sKind' % expr_eval['union'])
-        exprs.append(expr_eval)
+        exprs.append(evaluate(expr))
 
     return exprs
 

index 3a64769..e151659 100644
@@ -82,6 +82,8 @@ def evaluate(string):
         add_enum(expr_eval['enum'])
     elif expr_eval.has_key('union'):
         add_enum('%sKind' % expr_eval['union'])
+    elif expr_eval.has_key('type'):
+        add_struct(expr_eval)
 
     return expr_eval
 

@@ -107,6 +109,11 @@ def parse_schema(fp):
     return exprs
 
 def parse_args(typeinfo):
+    if isinstance(typeinfo, basestring):
+        struct = find_struct(typeinfo)
+        assert struct != None
+        typeinfo = struct['data']
+
     for member in typeinfo:
         argname = member
         argentry = typeinfo[member]

@@ -176,6 +183,18 @@ def type_name(name):
     return name
 
 enum_types = []
+struct_types = []
+
+def add_struct(definition):
+    global struct_types
+    struct_types.append(definition)
+
+def find_struct(name):
+    global struct_types
+    for struct in struct_types:
+        if struct['type'] == name:
+            return struct
+    return None
 
 def add_enum(name):
     global enum_types

index a80ee40..54fbeef 100644
@@ -1652,16 +1652,7 @@
 #
 # Generates a synchronous snapshot of a block device.
 #
-# @device:  the name of the device to generate the snapshot from.
-#
-# @snapshot-file: the target of the new image. If the file exists, or if it
-#                 is a device, the snapshot will be created in the existing
-#                 file/device. If does not exist, a new file will be created.
-#
-# @format: #optional the format of the snapshot image, default is 'qcow2'.
-#
-# @mode: #optional whether and how QEMU should create a new image, default is
-#        'absolute-paths'.
+# For the arguments, see the documentation of BlockdevSnapshot.
 #
 # Returns: nothing on success
 #          If @device is not a valid block device, DeviceNotFound

@@ -1669,8 +1660,7 @@
 # Since 0.14.0
 ##
 { 'command': 'blockdev-snapshot-sync',
-  'data': { 'device': 'str', 'snapshot-file': 'str', '*format': 'str',
-            '*mode': 'NewImageMode'} }
+  'data': 'BlockdevSnapshot' }
 
 ##
 # @human-monitor-command: