qapi: Move exprs checking from parse_schema() to check_exprs()

To have expression semantic analysis in one place rather than two.

Backports commit 4d076d67c2c74662db092ecf4f99600b18209b2e from qemu

qemu/scripts/qapi.py

@@ -602,26 +602,6 @@ def check_struct(expr, expr_info):
     if expr.get('base'):
         check_member_clash(expr_info, expr['base'], expr['data'])
 
-def check_exprs(schema):
-    for expr_elem in schema.exprs:
-        expr = expr_elem['expr']
-        info = expr_elem['info']
-
-        if expr.has_key('enum'):
-            check_enum(expr, info)
-        elif expr.has_key('union'):
-            check_union(expr, info)
-        elif expr.has_key('alternate'):
-            check_alternate(expr, info)
-        elif expr.has_key('struct'):
-            check_struct(expr, info)
-        elif expr.has_key('command'):
-            check_command(expr, info)
-        elif expr.has_key('event'):
-            check_event(expr, info)
-        else:
-            assert False, 'unexpected meta type'
-
 def check_keys(expr_elem, meta, required, optional=[]):
     expr = expr_elem['expr']
     info = expr_elem['info']
@@ -645,24 +625,13 @@ def check_keys(expr_elem, meta, required, optional=[]):
                                 "Key '%s' is missing from %s '%s'"
                                 % (key, meta, name))
 
-
+def check_exprs(exprs):
-def parse_schema(fname):
     global all_names
-    exprs = []
 
-    # First pass: read entire file into memory
+    # Learn the types and check for valid expression keys
-    try:
-        schema = QAPISchema(open(fname, "r"))
-    except (QAPISchemaError, QAPIExprError), e:
-        print >>sys.stderr, e
-        exit(1)
-
-    try:
-        # Next pass: learn the types and check for valid expression keys. At
-        # this point, top-level 'include' has already been flattened.
     for builtin in builtin_types.keys():
         all_names[builtin] = 'built-in'
-        for expr_elem in schema.exprs:
+    for expr_elem in exprs:
         expr = expr_elem['expr']
         info = expr_elem['info']
         if expr.has_key('enum'):
@@ -688,10 +657,9 @@ def parse_schema(fname):
         else:
             raise QAPIExprError(expr_elem['info'],
                                 "Expression is missing metatype")
-            exprs.append(expr)
 
     # Try again for hidden UnionKind enum
-        for expr_elem in schema.exprs:
+    for expr_elem in exprs:
         expr = expr_elem['expr']
         if expr.has_key('union'):
             if not discriminator_find_enum_define(expr):
@@ -701,14 +669,36 @@ def parse_schema(fname):
             add_enum('%sKind' % expr['alternate'], expr_elem['info'],
                      implicit=True)
 
-        # Final pass - validate that exprs make sense
+    # Validate that exprs make sense
-        check_exprs(schema)
+    for expr_elem in exprs:
-    except QAPIExprError, e:
+        expr = expr_elem['expr']
+        info = expr_elem['info']
+
+        if expr.has_key('enum'):
+            check_enum(expr, info)
+        elif expr.has_key('union'):
+            check_union(expr, info)
+        elif expr.has_key('alternate'):
+            check_alternate(expr, info)
+        elif expr.has_key('struct'):
+            check_struct(expr, info)
+        elif expr.has_key('command'):
+            check_command(expr, info)
+        elif expr.has_key('event'):
+            check_event(expr, info)
+        else:
+            assert False, 'unexpected meta type'
+
+    return map(lambda expr_elem: expr_elem['expr'], exprs)
+
+def parse_schema(fname):
+    try:
+        schema = QAPISchema(open(fname, "r"))
+        return check_exprs(schema.exprs)
+    except (QAPISchemaError, QAPIExprError), e:
         print >>sys.stderr, e
         exit(1)
 
-    return exprs
-
 def parse_args(typeinfo):
     if isinstance(typeinfo, str):
         struct = find_struct(typeinfo)