WTF NPAPI extension. Early draft.

tools/nixysa/nixysa/callback_binding.py

Index: tools/nixysa/nixysa/callback_binding.py
===================================================================
--- tools/nixysa/nixysa/callback_binding.py	(revision 0)
+++ tools/nixysa/nixysa/callback_binding.py	(revision 0)
@@ -0,0 +1,562 @@
+#!/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.
+
+"""callback binding model module.
+
+This module implements the glue functions for the callback binding model, that
+is used by JS callback types. This binding works in reverse in the sense that a
+C++ object is created to wrap the JS object.
+
+In C++, objects using this binding model are passed by pointer to an object
+that has a corresponding 'Run' function.
+Note that every time a callback is passed to C++ a new object is created. The
+function called is responsible for deleting it when appropriate.
+
+Note: As of currently, the Callback objects cannot be returned.
+
+For example:
+void SetFrameCallback(FrameCallback *callback);
+...
+vod OnFrame(float elapsed_time) {
+  frame_callback->Run(elapsed_time);
+}
+
+For JS bindings, they are directly represented by a JavaScript function object.
+"""
+
+import string
+import sys
+import cpp_utils
+import java_utils
+import npapi_utils
+import syntax_tree
+
+
+class Error(Exception):
+  """Base exception for the callback_binding module."""
+
+
+class InvalidCallbackUsageError(Error):
+  """Raised when a callback is used incorrectly."""
+
+
+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), False
+
+
+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 '%s*' % cpp_utils.GetScopedName(scope, type_defn), False
+
+
+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 '%s*' % cpp_utils.GetScopedName(scope, type_defn), False
+
+
+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 '%s*' % cpp_utils.GetScopedName(scope, type_defn), False
+
+
+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), False
+
+
+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 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:
+    InvalidCallbackUsageError: always. This function can't be called for a
+    Callback type.
+  """
+  raise InvalidCallbackUsageError
+
+
+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:
+    InvalidCallbackUsageError: always. This function can't be called for a
+    Callback type.
+  """
+  raise InvalidCallbackUsageError
+
+
+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:
+    InvalidCallbackUsageError: always. This function can't be called for a
+    Callback type.
+  """
+  raise InvalidCallbackUsageError
+
+
+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:
+    InvalidCallbackUsageError: always. This function can't be called for a
+    Callback type.
+  """
+  raise InvalidCallbackUsageError
+
+
+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:
+    InvalidCallbackUsageError: always. This function can't be called for a
+    Callback type.
+  """
+  raise InvalidCallbackUsageError
+
+
+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:
+    InvalidCallbackUsageError: always. This function can't be called for a
+    Callback type.
+  """
+  raise InvalidCallbackUsageError
+
+
+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:
+    InvalidCallbackUsageError: always. This function can't be called for a
+    Callback type.
+  """
+  raise InvalidCallbackUsageError
+
+
+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:
+    InvalidCallbackUsageError: always. This function can't be called for a
+    Callback type.
+  """
+  raise InvalidCallbackUsageError
+
+
+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.
+  """
+  param_types = []
+  for param in type_defn.params:
+    param_binding_model = param.type_defn.binding_model
+    param_types.append(param_binding_model.JSDocTypeString(param.type_defn))
+  return_binding_model = type_defn.type_defn.binding_model
+  return_type = return_binding_model.JSDocTypeString(type_defn.type_defn)
+  return 'function(%s): %s' % (', '.join(param_types), return_type)
+
+
+def _MakeRunFunction(scope, type_defn):
+  """Creates the Run function for the callback class.
+
+  Args:
+    scope: the scope for the function.
+    type_defn: the callback definition.
+
+  Returns:
+    a Function, with the same parameters as the callback.
+  """
+  function = syntax_tree.Function(type_defn.source, {}, 'Run', None, [])
+  function.type_defn = type_defn.type_defn
+  function.parent = scope
+  function.params = type_defn.params
+  return function
+
+
+_npapi_binding_glue_header_template = string.Template("""
+class ${GlueClass} : public ${BaseClass} {
+ public:
+  ${GlueClass}(NPP npp, NPObject *npobject);
+  virtual ~${GlueClass}();
+  virtual ${RunFunction};
+ private:
+  NPP npp_;
+  NPObject *npobject_;
+};
+${GlueClass} *CreateObject(NPP npp, NPObject *npobject);
+""")
+
+
+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.
+  """
+  glue_class = type_defn.name + '_glue'
+  base_class = cpp_utils.GetScopedName(scope, type_defn)
+  run_function, unused_check = cpp_utils.GetFunctionPrototype(
+      scope, _MakeRunFunction(scope, type_defn), '')
+  return _npapi_binding_glue_header_template.substitute(
+      GlueClass=glue_class,
+      BaseClass=base_class,
+      RunFunction=run_function)
+
+
+_npapi_binding_glue_cpp_template = string.Template("""
+${GlueClass}::${GlueClass}(NPP npp, NPObject *npobject)
+    : npp_(npp),
+      npobject_(npobject) {
+  NPN_RetainObject(npobject);
+}
+
+${GlueClass}::~${GlueClass}() {
+  // TODO: The NPObject we should be releasing here might have already been
+  // destroyed by the browser due to a Firefox bug.  The following line is
+  // commented out in order to avoid a browser crash.
+  //g_browser->releaseobject(npobject_);
+}
+
+${RunFunction} {
+  ${CallbackGlue};
+}
+
+${GlueClass} *CreateObject(NPP npp, NPObject *npobject) {
+  return npobject ? new ${GlueClass}(npp, npobject) : NULL;
+}
+""")
+
+
+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.
+  """
+  glue_class = type_defn.name + '_glue'
+
+  run_function, unused_check = cpp_utils.GetFunctionPrototype(
+      scope, _MakeRunFunction(scope, type_defn), glue_class + '::')
+
+  if 'async' in type_defn.attributes:
+    async_param = 'true'
+  else:
+    async_param = 'false'
+
+  callback_glue = 'return RunCallback(npp_, npobject_, %s' % async_param
+  if type_defn.params:
+    callback_glue += ', '.join([''] + [t.name for t in type_defn.params])
+  callback_glue += ')'
+
+  return _npapi_binding_glue_cpp_template.substitute(
+      GlueClass=glue_class,
+      RunFunction=run_function,
+      CallbackGlue=callback_glue)
+
+
+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:
+    InvalidCallbackUsageError: always. This function can't be called for a
+    Callback type.
+  """
+  raise InvalidCallbackUsageError
+
+_from_npvariant_template = string.Template("""
+  ${success} = NPVARIANT_IS_OBJECT(${input_expr});
+  ${type_name} *${variable} = NULL;
+  if (${success}) {
+    ${variable} = ${namespace}::CreateObject(
+       ${npp}, NPVARIANT_TO_OBJECT(${input_expr}));
+  } else {
+    *error_handle = "Error in " ${context}
+        ": a callback must be a Javascript function.";
+  }""")
+
+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.
+  """
+  type_name = cpp_utils.GetScopedName(scope, type_defn)
+  callback_glue_namespace = npapi_utils.GetGlueFullNamespace(type_defn)
+  text = _from_npvariant_template.substitute(success=success,
+                                             context=exception_context,
+                                             input_expr=input_expr,
+                                             type_name=type_name,
+                                             variable=variable,
+                                             namespace=callback_glue_namespace,
+                                             npp=npp)
+  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.
+
+  Raises:
+    InvalidCallbackUsageError: always. This function can't be called for a
+    Callback type.
+  """
+  raise InvalidCallbackUsageError
+
+
+def main(unused_argv):
+  pass
+
+if __name__ == '__main__':
+  main(sys.argv)
Property changes on: tools/nixysa/nixysa/callback_binding.py
___________________________________________________________________
Added: svn:eol-style
   + LF