1 files changed, 93 insertions, 0 deletions
diff --git a/utils/ipc/mojo/public/tools/mojom/mojom/generate/constant_resolver.py b/utils/ipc/mojo/public/tools/mojom/mojom/generate/constant_resolver.py
new file mode 100644
index 00000000..0dfd996e
--- /dev/null
+++ b/utils/ipc/mojo/public/tools/mojom/mojom/generate/constant_resolver.py
@@ -0,0 +1,93 @@
+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+"""Resolves the values used for constants and enums."""
+
+from itertools import ifilter
+
+from mojom.generate import module as mojom
+
+
+def ResolveConstants(module, expression_to_text):
+  in_progress = set()
+  computed = set()
+
+  def GetResolvedValue(named_value):
+    assert isinstance(named_value, (mojom.EnumValue, mojom.ConstantValue))
+    if isinstance(named_value, mojom.EnumValue):
+      field = next(
+          ifilter(lambda field: field.name == named_value.name,
+                  named_value.enum.fields), None)
+      if not field:
+        raise RuntimeError(
+            'Unable to get computed value for field %s of enum %s' %
+            (named_value.name, named_value.enum.name))
+      if field not in computed:
+        ResolveEnum(named_value.enum)
+      return field.resolved_value
+    else:
+      ResolveConstant(named_value.constant)
+      named_value.resolved_value = named_value.constant.resolved_value
+      return named_value.resolved_value
+
+  def ResolveConstant(constant):
+    if constant in computed:
+      return
+    if constant in in_progress:
+      raise RuntimeError('Circular dependency for constant: %s' % constant.name)
+    in_progress.add(constant)
+    if isinstance(constant.value, (mojom.EnumValue, mojom.ConstantValue)):
+      resolved_value = GetResolvedValue(constant.value)
+    else:
+      resolved_value = expression_to_text(constant.value)
+    constant.resolved_value = resolved_value
+    in_progress.remove(constant)
+    computed.add(constant)
+
+  def ResolveEnum(enum):
+    def ResolveEnumField(enum, field, default_value):
+      if field in computed:
+        return
+      if field in in_progress:
+        raise RuntimeError('Circular dependency for enum: %s' % enum.name)
+      in_progress.add(field)
+      if field.value:
+        if isinstance(field.value, mojom.EnumValue):
+          resolved_value = GetResolvedValue(field.value)
+        elif isinstance(field.value, str):
+          resolved_value = int(field.value, 0)
+        else:
+          raise RuntimeError('Unexpected value: %s' % field.value)
+      else:
+        resolved_value = default_value
+      field.resolved_value = resolved_value
+      in_progress.remove(field)
+      computed.add(field)
+
+    current_value = 0
+    for field in enum.fields:
+      ResolveEnumField(enum, field, current_value)
+      current_value = field.resolved_value + 1
+
+  for constant in module.constants:
+    ResolveConstant(constant)
+
+  for enum in module.enums:
+    ResolveEnum(enum)
+
+  for struct in module.structs:
+    for constant in struct.constants:
+      ResolveConstant(constant)
+    for enum in struct.enums:
+      ResolveEnum(enum)
+    for field in struct.fields:
+      if isinstance(field.default, (mojom.ConstantValue, mojom.EnumValue)):
+        field.default.resolved_value = GetResolvedValue(field.default)
+
+  for interface in module.interfaces:
+    for constant in interface.constants:
+      ResolveConstant(constant)
+    for enum in interface.enums:
+      ResolveEnum(enum)
+
+  return module