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 * Copyright (C) 2010 Google Inc. All rights reserved.

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 * modification, are permitted provided that the following conditions are

 * met:

 *

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 * notice, this list of conditions and the following disclaimer.

 *     * Redistributions in binary form must reproduce the above

 * copyright notice, this list of conditions and the following disclaimer

 * in the documentation and/or other materials provided with the

 * distribution.

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 * contributors may be used to endorse or promote products derived from

 * this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

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/*

  This file contains the declaration for CppVariant, a type used by C++ classes

  that are to be bound to JavaScript objects.

  CppVariant exists primarily as an interface between C++ callers and the

  corresponding NPVariant type.  CppVariant also provides a number of

  convenience constructors and accessors, so that the NPVariantType values

  don't need to be exposed, and a destructor to free any memory allocated for

  string values.

*/

#ifndef CppVariant_h

#define CppVariant_h

#include "base/basictypes.h"

#include "public/WebBindings.h"

#include <string>

#include <wtf/Vector.h>

class CppVariant : public NPVariant {

public:

    CppVariant();

    ~CppVariant();

    void setNull();

    void set(bool);

    void set(int32_t);

    void set(double);

    // Note that setting a CppVariant to a string value involves copying the

    // string data, which must be freed with a call to freeData() when the

    // CppVariant is set to a different value or is no longer needed.  Normally

    // this is handled by the other set() methods and by the destructor.

    void set(const char*); // Must be a null-terminated string.

    void set(const std::string&);

    void set(const NPString&);

    void set(const NPVariant&);

    // Note that setting a CppVariant to an NPObject involves ref-counting

    // the actual object. freeData() should only be called if the CppVariant

    // is no longer needed. The other set() methods handle this internally.

    // Also, the object's NPClass is expected to be a static object: neither

    // the NP runtime nor CppVariant will ever free it.

    void set(NPObject*_value);

    // These three methods all perform deep copies of any string data.  This

    // allows local CppVariants to be released by the destructor without

    // corrupting their sources. In performance-critical code, or when strings

    // are very long, avoid creating new CppVariants.

    // In case of NPObject as the data, the copying involves ref-counting

    // as opposed to deep-copying. The ref-counting ensures that sources don't

    // get corrupted when the copies get destroyed.

    void copyToNPVariant(NPVariant* result) const;

    CppVariant& operator=(const CppVariant& original);

    CppVariant(const CppVariant& original);

    // Calls NPN_ReleaseVariantValue, which frees any string data

    // held by the object and sets its type to null.

    // In case of NPObject, the NPN_ReleaseVariantValue decrements

    // the ref-count (releases when ref-count becomes 0)

    void freeData();

    // Compares this CppVariant's type and value to another's.  They must be

    // identical in both type and value to be considered equal.  For string and

    // object types, a deep comparison is performed; that is, the contents of the

    // strings, or the classes and refcounts of the objects, must be the same,

    // but they need not be the same pointers.

    bool isEqual(const CppVariant&) const;

    // The value of a CppVariant may be read directly from its NPVariant (but

    // should only be set using one of the set() methods above). Although the

    // type of a CppVariant is likewise public, it can be accessed through these

    // functions rather than directly if a caller wishes to avoid dependence on

    // the NPVariantType values.

    bool isBool() const { return (type == NPVariantType_Bool); }

    bool isInt32() const { return (type == NPVariantType_Int32); }

    bool isDouble() const { return (type == NPVariantType_Double); }

    bool isNumber() const { return (isInt32() || isDouble()); }

    bool isString() const { return (type == NPVariantType_String); }

    bool isVoid() const { return (type == NPVariantType_Void); }

    bool isNull() const { return (type == NPVariantType_Null); }

    bool isEmpty() const { return (isVoid() || isNull()); }

    bool isObject() const { return (type == NPVariantType_Object); }

    // Converters.  The CppVariant must be of a type convertible to these values.

    // For example, toInt32() works only if isNumber() is true.

    std::string toString() const;

    int32_t toInt32() const;

    double toDouble() const;

    bool toBoolean() const;

    // Returns a vector of strings for the specified argument. This is useful

    // for converting a JavaScript array of strings into a vector of strings.

    Vector<std::string> toStringVector() const;

    // Invoke method of the given name on an object with the supplied arguments.

    // The first argument should be the object on which the method is to be

    // invoked.  Returns whether the method was successfully invoked.  If the

    // method was invoked successfully, any return value is stored in the

    // CppVariant specified by result.

    bool invoke(const std::string&, const CppVariant* arguments,

                uint32_t argumentCount, CppVariant& result) const;

};

#endif // CppVariant_h