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diff --git a/webkit/plugins/ppapi/npapi_glue.h b/webkit/plugins/ppapi/npapi_glue.h
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+++ b/webkit/plugins/ppapi/npapi_glue.h
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+// Copyright (c) 2010 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.
+
+#ifndef WEBKIT_PLUGINS_PPAPI_NPAPI_GLUE_H_
+#define WEBKIT_PLUGINS_PPAPI_NPAPI_GLUE_H_
+
+#include "base/basictypes.h"
+#include "base/scoped_ptr.h"
+#include "ppapi/c/pp_var.h"
+
+struct NPObject;
+typedef struct _NPVariant NPVariant;
+typedef void* NPIdentifier;
+
+namespace webkit {
+namespace ppapi {
+
+class PluginModule;
+class PluginObject;
+
+// Utilities -------------------------------------------------------------------
+
+// Converts the given PP_Var to an NPVariant, returning true on success.
+// False means that the given variant is invalid. In this case, the result
+// NPVariant will be set to a void one.
+//
+// The contents of the PP_Var will be copied unless the PP_Var corresponds to
+// an object.
+bool PPVarToNPVariant(PP_Var var, NPVariant* result);
+
+// PPResultAndExceptionToNPResult ----------------------------------------------
+
+// Convenience object for converting a PPAPI call that can throw an exception
+// and optionally return a value, back to the NPAPI layer which expects a
+// NPVariant as a result.
+//
+// Normal usage is that you will pass the result of exception() to the
+// PPAPI function as the exception output parameter. Then you will either
+// call SetResult with the result of the PPAPI call, or
+// CheckExceptionForNoResult if the PPAPI call doesn't return a PP_Var.
+//
+// Both SetResult and CheckExceptionForNoResult will throw an exception to
+// the JavaScript library if the plugin reported an exception. SetResult
+// will additionally convert the result to an NPVariant and write it to the
+// output parameter given in the constructor.
+class PPResultAndExceptionToNPResult {
+ public:
+  // The object_var parameter is the object to associate any exception with.
+  // It may not be NULL.
+  //
+  // The np_result parameter is the NPAPI result output parameter. This may be
+  // NULL if there is no NPVariant result (like for HasProperty). If this is
+  // specified, you must call SetResult() to set it. If it is not, you must
+  // call CheckExceptionForNoResult to do the exception checking with no result
+  // conversion.
+  PPResultAndExceptionToNPResult(NPObject* object_var, NPVariant* np_result);
+
+  ~PPResultAndExceptionToNPResult();
+
+  // Returns true if an exception has been set.
+  bool has_exception() const { return exception_.type != PP_VARTYPE_UNDEFINED; }
+
+  // Returns a pointer to the exception. You would pass this to the PPAPI
+  // function as the exception parameter. If it is set to non-void, this object
+  // will take ownership of destroying it.
+  PP_Var* exception() { return &exception_; }
+
+  // Returns true if everything succeeded with no exception. This is valid only
+  // after calling SetResult/CheckExceptionForNoResult.
+  bool success() const {
+    return success_;
+  }
+
+  // Call this with the return value of the PPAPI function. It will convert
+  // the result to the NPVariant output parameter and pass any exception on to
+  // the JS engine. It will update the success flag and return it.
+  bool SetResult(PP_Var result);
+
+  // Call this after calling a PPAPI function that could have set the
+  // exception. It will pass the exception on to the JS engine and update
+  // the success flag.
+  //
+  // The success flag will be returned.
+  bool CheckExceptionForNoResult();
+
+  // Call this to ignore any exception. This prevents the DCHECK from failing
+  // in the destructor.
+  void IgnoreException();
+
+ private:
+  // Throws the current exception to JS. The exception must be set.
+  void ThrowException();
+
+  NPObject* object_var_;  // Non-owning ref (see constructor).
+  NPVariant* np_result_;  // Output value, possibly NULL (see constructor).
+  PP_Var exception_;  // Exception set by the PPAPI call. We own a ref to it.
+  bool success_;  // See the success() function above.
+  bool checked_exception_;  // SetResult/CheckExceptionForNoResult was called.
+
+  DISALLOW_COPY_AND_ASSIGN(PPResultAndExceptionToNPResult);
+};
+
+// PPVarArrayFromNPVariantArray ------------------------------------------------
+
+// Converts an array of NPVariants to an array of PP_Var, and scopes the
+// ownership of the PP_Var. This is used when converting argument lists from
+// WebKit to the plugin.
+class PPVarArrayFromNPVariantArray {
+ public:
+  PPVarArrayFromNPVariantArray(PluginModule* module,
+                               size_t size,
+                               const NPVariant* variants);
+  ~PPVarArrayFromNPVariantArray();
+
+  PP_Var* array() { return array_.get(); }
+
+ private:
+  size_t size_;
+  scoped_array<PP_Var> array_;
+
+  DISALLOW_COPY_AND_ASSIGN(PPVarArrayFromNPVariantArray);
+};
+
+// PPVarFromNPObject -----------------------------------------------------------
+
+// Converts an NPObject tp PP_Var, and scopes the ownership of the PP_Var. This
+// is used when converting 'this' pointer from WebKit to the plugin.
+class PPVarFromNPObject {
+ public:
+  PPVarFromNPObject(PluginModule* module, NPObject* object);
+  ~PPVarFromNPObject();
+
+  PP_Var var() const { return var_; }
+
+ private:
+  const PP_Var var_;
+
+  DISALLOW_COPY_AND_ASSIGN(PPVarFromNPObject);
+};
+
+// NPObjectAccessorWithIdentifier ----------------------------------------------
+
+// Helper class for our NPObject wrapper. This converts a call from WebKit
+// where it gives us an NPObject and an NPIdentifier to an easily-accessible
+// ObjectVar (corresponding to the NPObject) and PP_Var (corresponding to the
+// NPIdentifier).
+//
+// If the NPObject or identifier is invalid, we'll set is_valid() to false.
+// The caller should check is_valid() before doing anything with the class.
+//
+// JS can't have integer functions, so when dealing with these, we don't want
+// to allow integer identifiers. The calling code can decode if it wants to
+// allow integer identifiers (like for property access) or prohibit them
+// (like for method calling) by setting |allow_integer_identifier|. If this
+// is false and the identifier is an integer, we'll set is_valid() to false.
+//
+// Getting an integer identifier in this case should be impossible. V8
+// shouldn't be allowing this, and the Pepper Var calls from the plugin are
+// supposed to error out before calling into V8 (which will then call us back).
+// Aside from an egregious error, the only time this could happen is an NPAPI
+// plugin calling us.
+class NPObjectAccessorWithIdentifier {
+ public:
+  NPObjectAccessorWithIdentifier(NPObject* object,
+                                 NPIdentifier identifier,
+                                 bool allow_integer_identifier);
+  ~NPObjectAccessorWithIdentifier();
+
+  // Returns true if both the object and identifier are valid.
+  bool is_valid() const {
+    return object_ && identifier_.type != PP_VARTYPE_UNDEFINED;
+  }
+
+  PluginObject* object() { return object_; }
+  PP_Var identifier() const { return identifier_; }
+
+ private:
+  PluginObject* object_;
+  PP_Var identifier_;
+
+  DISALLOW_COPY_AND_ASSIGN(NPObjectAccessorWithIdentifier);
+};
+
+}  // namespace ppapi
+}  // namespace webkit
+
+#endif  // WEBKIT_PLUGINS_PPAPI_NPAPI_GLUE_H_