mojo: Starting generator for python bindings.

mojo/public/tools/bindings/generators/mojom_python_generator.py

+# Copyright 2014 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.
+
+"""Generates Python source files from a mojom.Module."""
+
+import re
+
+import mojom.generate.generator as generator
+import mojom.generate.module as mojom
+from mojom.generate.template_expander import UseJinja
+
+
+def NameToComponent(name):
+  # insert '_' between anything and a Title name (e.g, HTTPEntry2FooBar ->
+  # HTTP_Entry2_FooBar)
+  name = re.sub('([^_])([A-Z][^A-Z_]+)', r'\1_\2', name)
+  # insert '_' between non upper and start of upper blocks (e.g.,
+  # HTTP_Entry2_FooBar -> HTTP_Entry2_Foo_Bar)
+  name = re.sub('([^A-Z_])([A-Z])', r'\1_\2', name)
+  return [x.lower() for x in name.split('_')]
+
+def UpperCamelCase(name):
+  return ''.join([x.capitalize() for x in NameToComponent(name)])
+
+def CamelCase(name):
+  uccc = UpperCamelCase(name)
+  return uccc[0].lower() + uccc[1:]
+
+def ConstantStyle(name):
+  components = NameToComponent(name)
+  if components[0] == 'k':
+    components = components[1:]
+  return '_'.join([x.upper() for x in components])
+
+def GetNameForElement(element):
+  if isinstance(element, (mojom.NamedValue,
+                          mojom.Constant)):
+    return ConstantStyle(element.name)
+  raise Exception('Unexpected element: ' % element)
+
+def TranslateConstants(token):
+  if isinstance(token, (mojom.EnumValue, mojom.NamedValue)):
+    # Both variable and enum constants are constructed like:
+    # NamespaceUid.Struct[.Enum].CONSTANT_NAME
+    name = []
+    if token.imported_from:
+      name.append(token.imported_from['python_module'])
+    if token.parent_kind:
+      name.append(GetNameForElement(token.parent_kind))
+    if isinstance(token, mojom.EnumValue):
+      name.append(GetNameForElement(token))
+    else:
+      name.append(token.name)
+    return '.'.join(name)
+
+  if isinstance(token, mojom.BuiltinValue):
+    if token.value == 'double.INFINITY' or token.value == 'float.INFINITY':
+      return 'float(\'inf\')';
+    if (token.value == 'double.NEGATIVE_INFINITY' or
+        token.value == 'float.NEGATIVE_INFINITY'):
+      return 'float(\'-inf\')'
+    if token.value == 'double.NAN' or token.value == 'float.NAN':
+      return 'float(\'nan\')';
+
+  return token
+
+
+def ExpressionToText(value):
+  return TranslateConstants(value)
+
+
+class Generator(generator.Generator):
+
+  python_filters = {
+    'expression_to_text': ExpressionToText,
+    'name': GetNameForElement,
+  }
+
+  @UseJinja('python_templates/module.py.tmpl', filters=python_filters)
+  def GeneratePythonModule(self):
+    return {
+      'imports': self.GetImports(),
+      'module': self.module,
+    }
+
+  def GenerateFiles(self, args):
+    self.Write(self.GeneratePythonModule(),
+               '%s.py' % self.module.name.replace('.mojom', '_mojom'))
+
+  def GetImports(self):
+    for each in self.module.imports:
+      each['python_module'] = each['module_name'].replace('.mojom', '_mojom')
+    return self.module.imports
+
+  def GetJinjaParameters(self):
+    return {
+      'lstrip_blocks': True,
+      'trim_blocks': True,
+    }