WTF NPAPI extension. Early draft.

tools/nixysa/nixysa/enum_binding.py

+#!/usr/bin/python2.4
+#
+# Copyright 2008 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""enum binding model module.
+
+This module implements the glue functions for the enum binding model, used by
+enum types. Enums behave almost exactly like ints, except range checking is
+performed when getting values from JavaScript.
+
+In C++, objects using this binding model are passed and returned by value (or
+by pointer when mutable). For example:
+void SetValue(Enum value);
+Enum GetValue();
+
+For JS bindings, they are directly represented by variants.
+"""
+
+import string
+import cpp_utils
+import java_utils
+
+
+class InvalidEnumUsage(Exception):
+  """Raised when an enum type is used incorrectly."""
+  pass
+
+
+def JavaMemberString(scope, type_defn):
+  """Gets the representation of a member name in Java.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition for the type.
+
+  Returns:
+    a string representing the type
+  """
+  return java_utils.GetScopedName(scope, type_defn)
+
+
+def CppTypedefString(scope, type_defn):
+  """Gets the representation of a type when used in a C++ typedef.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition for the type.
+
+  Returns:
+    a (string, boolean) pair, the first element being the representation of
+    the type, the second element indicating whether or not the definition of
+    the type is needed for the expression to be valid.
+  """
+  return cpp_utils.GetScopedName(scope, type_defn), True
+
+
+def CppMemberString(scope, type_defn):
+  """Gets the representation of a type when used as a C++ class member.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition for the type.
+
+  Returns:
+    a (string, boolean) pair, the first element being the representation of
+    the type, the second element indicating whether or not the definition of
+    the type is needed for the expression to be valid.
+  """
+  return cpp_utils.GetScopedName(scope, type_defn), True
+
+
+def CppReturnValueString(scope, type_defn):
+  """Gets the representation of a type when used as a C++ function return value.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition for the type.
+
+  Returns:
+    a (string, boolean) pair, the first element being the representation of
+    the type, the second element indicating whether or not the definition of
+    the type is needed for the expression to be valid.
+  """
+  return cpp_utils.GetScopedName(scope, type_defn), True
+
+
+def CppParameterString(scope, type_defn):
+  """Gets the representation of a type when used for a function parameter.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition for the type.
+
+  Returns:
+    a (string, boolean) pair, the first element being the representation of
+    the type, the second element indicating whether or not the definition of
+    the type is needed for the expression to be valid.
+  """
+  return cpp_utils.GetScopedName(scope, type_defn), True
+
+
+def CppMutableParameterString(scope, type_defn):
+  """Gets the representation of a type for a mutable function parameter.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition for the type.
+
+  Returns:
+    a (string, boolean) pair, the first element being the string representing
+    the type, the second element indicating whether or not the definition of
+    the type is needed for the expression to be valid.
+  """
+  return '%s*' % cpp_utils.GetScopedName(scope, type_defn), True
+
+
+def CppMutableToNonMutable(scope, type_defn, expr):
+  """Gets the string converting a mutable expression to a non-mutable one.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition for the type.
+    expr: a string for the mutable expression.
+
+  Returns:
+    a string, which is the non-mutable expression.
+  """
+  (scope, type_defn) = (scope, type_defn)  # silence gpylint.
+  return '*(%s)' % expr
+
+
+def CppBaseClassString(scope, type_defn):
+  """Gets the representation of a type for a base class.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition for the type.
+
+  Returns:
+    a (string, boolean) pair, the first element being the string representing
+    the type, the second element indicating whether or not the definition of
+    the type is needed for the expression to be valid.
+
+  Raises:
+    InvalidEnumUsage: always. This function can't be called for an enum type.
+  """
+  raise InvalidEnumUsage
+
+
+def CppCallMethod(scope, type_defn, object_expr, mutable, method, param_exprs):
+  """Gets the representation of a member function call.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition, representing the type of the object being called.
+    object_expr: a string, which is the expression for the object being called.
+    mutable: a boolean, whether or not the 'object_expr' expression is mutable
+      or not
+    method: a Function, representing the function to call.
+    param_exprs: a list of strings, each being the expression for the value of
+      each parameter.
+
+  Returns:
+    a string, which is the expression for the function call.
+
+  Raises:
+    InvalidEnumUsage: always. This function can't be called for an enum type.
+  """
+  raise InvalidEnumUsage
+
+
+def CppCallStaticMethod(scope, type_defn, method, param_exprs):
+  """Gets the representation of a static function call.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition, representing the type of the object being called.
+    method: a Function, representing the function to call.
+    param_exprs: a list of strings, each being the expression for the value of
+      each parameter.
+
+  Returns:
+    a string, which is the expression for the function call.
+
+  Raises:
+    InvalidEnumUsage: always. This function can't be called for an enum type.
+  """
+  raise InvalidEnumUsage
+
+
+def CppCallConstructor(scope, type_defn, method, param_exprs):
+  """Gets the representation of a constructor call.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition, representing the type of the object being called.
+    method: a Function, representing the constructor to call.
+    param_exprs: a list of strings, each being the expression for the value of
+      each parameter.
+
+  Returns:
+    a string, which is the expression for the constructor call.
+
+  Raises:
+    InvalidEnumUsage: always. This function can't be called for an enum type.
+  """
+  raise InvalidEnumUsage
+
+
+def CppSetField(scope, type_defn, object_expr, field, param_expr):
+  """Gets the representation of an expression setting a field in an object.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition, representing the type of the object containing the
+      field being set.
+    object_expr: a string, which is the expression for the object containing
+      the field being set.
+    field: a string, the name of the field to be set.
+    param_expr: a strings, being the expression for the value to be set.
+
+  Returns:
+    a string, which is the expression for setting the field.
+
+  Raises:
+    InvalidEnumUsage: always. This function can't be called for an enum type.
+  """
+  raise InvalidEnumUsage
+
+
+def CppGetField(scope, type_defn, object_expr, field):
+  """Gets the representation of an expression getting a field in an object.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition, representing the type of the object containing the
+      field being retrieved.
+    object_expr: a string, which is the expression for the object containing
+      the field being retrieved.
+    field: a string, the name of the field to be retrieved.
+
+  Returns:
+    a string, which is the expression for getting the field.
+
+  Raises:
+    InvalidEnumUsage: always. This function can't be called for an enum type.
+  """
+  raise InvalidEnumUsage
+
+
+def CppSetStatic(scope, type_defn, field, param_expr):
+  """Gets the representation of an expression setting a static field.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition, representing the type of the object containing the
+      field being set.
+    field: a string, the name of the field to be set.
+    param_expr: a strings, being the expression for the value to be set.
+
+  Returns:
+    a string, which is the expression for setting the field.
+
+  Raises:
+    InvalidEnumUsage: always. This function can't be called for an enum type.
+  """
+  raise InvalidEnumUsage
+
+
+def CppGetStatic(scope, type_defn, field):
+  """Gets the representation of an expression getting a static field.
+
+  Args:
+    scope: a Definition for the scope in which the expression will be written.
+    type_defn: a Definition, representing the type of the object containing the
+      field being retrieved.
+    field: a string, the name of the field to be retrieved.
+
+  Returns:
+    a string, which is the expression for getting the field.
+
+  Raises:
+    InvalidEnumUsage: always. This function can't be called for an enum type.
+  """
+  raise InvalidEnumUsage
+
+
+def NpapiBindingGlueHeader(scope, type_defn):
+  """Gets the NPAPI glue header for a given type.
+
+  Args:
+    scope: a Definition for the scope in which the glue will be written.
+    type_defn: a Definition, representing the type.
+
+  Returns:
+    a string, the glue header.
+
+  Raises:
+    InvalidEnumUsage: always. This function can't be called for an enum type.
+  """
+  raise InvalidEnumUsage
+
+
+def NpapiBindingGlueCpp(scope, type_defn):
+  """Gets the NPAPI glue implementation for a given type.
+
+  Args:
+    scope: a Definition for the scope in which the glue will be written.
+    type_defn: a Definition, representing the type.
+
+  Returns:
+    a string, the glue implementation.
+
+  Raises:
+    InvalidEnumUsage: always. This function can't be called for an enum type.
+  """
+  raise InvalidEnumUsage
+
+
+def JSDocTypeString(type_defn):
+  """Gets the representation of a type in JSDoc notation.
+
+  Args:
+    type_defn: a Definition for the type.
+
+  Returns:
+    a string that is the JSDoc notation of type_defn.
+  """
+  type_defn = type_defn.GetFinalType()
+  type_stack = type_defn.GetParentScopeStack()
+  name = type_defn.name
+  return '.'.join([s.name for s in type_stack[1:]] + [name])
+
+
+def NpapiDispatchFunctionHeader(scope, type_defn, variable, npp, success):
+  """Gets a header for NPAPI glue dispatch functions.
+
+  This function creates a string containing a C++ code snippet that should be
+  included at the beginning of NPAPI glue dispatch functions like Invoke or
+  GetProperty. This code snippet will declare and initialize certain variables
+  that will be used in the dispatch functions, like the NPObject representing
+  the object, or a pointer to the NPP instance.
+
+  Args:
+    scope: a Definition for the scope in which the glue will be written.
+    type_defn: a Definition, representing the type.
+    variable: a string, representing a name of a variable that can be used to
+      store a reference to the object.
+    npp: a string, representing the name of the variable that holds the pointer
+      to the NPP instance. Will be declared by the code snippet.
+    success: the name of a bool variable containing the current success status.
+      (is not declared by the code snippet).
+
+  Returns:
+    a (string, string) pair, the first string being the code snippet, and the
+    second string being an expression to access the object.
+
+  Raises:
+    InvalidEnumUsage: always. This function can't be called for an enum type.
+  """
+  raise InvalidEnumUsage
+
+
+_enum_from_npvariant_template = string.Template("""
+${type} ${variable} = ${first};
+if (NPVARIANT_IS_NUMBER(${input})) {
+  ${variable} = (${type})(int)NPVARIANT_TO_NUMBER(${input});
+  if (${variable} < ${first} || ${variable} > ${last}) {
+    *error_handle = "Error in " ${context}
+        ": value out of range.";
+    ${result} = false;
+  }
+} else {
+  *error_handle = "Error in " ${context}
+      ": was expecting a number.";
+  ${result} = false;
+}""")
+
+
+def NpapiFromNPVariant(scope, type_defn, input_expr, variable, success,
+    exception_context, npp):
+  """Gets the string to get a value from a NPVariant.
+
+  This function creates a string containing a C++ code snippet that is used to
+  retrieve a value from a NPVariant. If an error occurs, like if the NPVariant
+  is not of the correct type, the snippet will set the success status variable
+  to false.
+
+  Args:
+    scope: a Definition for the scope in which the glue will be written.
+    type_defn: a Definition, representing the type of the value.
+    input_expr: an expression representing the NPVariant to get the value from.
+    variable: a string, representing a name of a variable that can be used to
+      store a reference to the value.
+    success: the name of a bool variable containing the current success status.
+    exception_context: the name of a string containing context information, for
+      use in exception reporting.
+    npp: a string, representing the name of the variable that holds the pointer
+      to the NPP instance.
+
+  Returns:
+    a (string, string) pair, the first string being the code snippet and the
+    second one being the expression to access that value.
+
+  Raises:
+    InvalidEnumUsage: if the type is not an enum, or the enum doesn't have any
+      values.
+  """
+  npp = npp  # silence gpylint.
+  final_type = type_defn.GetFinalType()
+  if final_type.defn_type != 'Enum':
+    raise InvalidEnumUsage
+  if not final_type.values:
+    raise InvalidEnumUsage
+  type_name = cpp_utils.GetScopedName(scope, type_defn)
+  first_value = (cpp_utils.GetScopePrefix(scope, final_type) +
+                 final_type.values[0].name)
+  last_value = (cpp_utils.GetScopePrefix(scope, final_type) +
+                final_type.values[-1].name)
+  text = _enum_from_npvariant_template.substitute(type=type_name,
+                                                  variable=variable,
+                                                  first=first_value,
+                                                  last=last_value,
+                                                  input=input_expr,
+                                                  result=success,
+                                                  context=exception_context)
+  return text, variable
+
+
+def NpapiExprToNPVariant(scope, type_defn, variable, expression, output,
+                         success, npp):
+  """Gets the string to store a value into a NPVariant.
+
+  This function creates a string containing a C++ code snippet that is used to
+  store a value into a NPVariant. That operation takes two phases, one that
+  allocates necessary NPAPI resources, and that can fail, and one that actually
+  sets the NPVariant (that can't fail). If an error occurs, the snippet will
+  set the success status variable to false.
+
+  Args:
+    scope: a Definition for the scope in which the glue will be written.
+    type_defn: a Definition, representing the type of the value.
+    variable: a string, representing a name of a variable that can be used to
+      store a reference to the value.
+    expression: a string representing the expression that yields the value to
+      be stored.
+    output: an expression representing a pointer to the NPVariant to store the
+      value into.
+    success: the name of a bool variable containing the current success status.
+    npp: a string, representing the name of the variable that holds the pointer
+      to the NPP instance.
+
+  Returns:
+    a (string, string) pair, the first string being the code snippet for the
+    first phase, and the second one being the code snippet for the second phase.
+  """
+  (success, npp) = (success, npp)  # silence gpylint.
+  type_name = cpp_utils.GetScopedName(scope, type_defn)
+  return ('%s %s = %s;' % (type_name, variable, expression),
+          'INT32_TO_NPVARIANT(%s, *%s);' % (variable, output))
+
+
+def main():
+  pass
+
+if __name__ == '__main__':
+  main()