First round of dead file removal

experimental/c_salt/variant.h

-// Copyright 2010 The Ginsu 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 C_SALT_VARIANT_H_
-#define C_SALT_VARIANT_H_
-
-#include <string>
-
-#include "boost/static_assert.hpp"
-#include "boost/type_traits/is_base_and_derived.hpp"
-#include "boost/variant.hpp"
-#include "c_salt/converting_visitor.h"
-#include "c_salt/scriptable_native_object_ptrs.h"
-#include "c_salt/scriptable_native_object.h"
-#include "c_salt/scripting_interface.h"
-#include "c_salt/scripting_interface_ptrs.h"
-
-namespace c_salt {
-
-class ScriptingBridge;
-
-// A polymorphic type container.  You can always get the value as any of the
-// intrisic types, no matter what the underlying storage actually is.  For
-// example, if you create a Variant using the string "3.14159", you can get
-// its double_value(), which will be 3.14159.  The value is immutable.  Note:
-// making copies of Variant instances using the copy constructor might cause a
-// round trip to the browser in order to perform reference counting.
-
-class Variant {
- public:
-
-  typedef enum {
-    kNullVariantType,
-    kBoolVariantType,
-    kInt32VariantType,
-    kDoubleVariantType,
-    kStringVariantType,
-    kObjectVariantType
-  } VariantType;
-
-  // Create a new Variant with the corresponding underlying storage.  The caller
-  // is responsible for deleting the resulting Type.
-  Variant() : variant_type_(kNullVariantType) {}
-  explicit Variant(bool bool_value)
-      : variant_type_(kBoolVariantType), value_(bool_value) {}
-  explicit Variant(int32_t int32_value)
-      : variant_type_(kInt32VariantType), value_(int32_value) {}
-  explicit Variant(double double_value)
-      : variant_type_(kDoubleVariantType), value_(double_value) {}
-  // Creates a deep copy of |string_value|, this object instance manages the
-  // string's memory.
-  explicit Variant(const std::string& string_value)
-      : variant_type_(kStringVariantType), value_(string_value) {}
-  // Note that this ctor will cause two copies of |string_value| to happen.
-  explicit Variant(const char* string_value)
-      : variant_type_(kStringVariantType), value_(std::string(string_value)) {}
-  // Hold a shared reference to |object_value|.
-  explicit Variant(SharedScriptingInterface object_value)
-      : variant_type_(kObjectVariantType), value_(object_value) {}
-
-  // This constructor handles creating a Variant from a pointer to
-  // ScriptableNativeObject.  This is done by getting a shared pointer to the
-  // ScriptingBridge associated with the ScriptableNativeObject.
-  //
-  // If the ScriptingBridge associated with the given native object has gone
-  // away, then we can't represent that object in a c_salt Variant, and
-  // therefore the constructed Variant will be of Null type.
-  template <class T>
-  explicit Variant(boost::shared_ptr<T> native_object)
-      : variant_type_(kObjectVariantType) {
-    // This constructor only works if T inherits from ScriptableNativeObject.
-    BOOST_STATIC_ASSERT((boost::is_base_and_derived<ScriptableNativeObject,
-                                                    T>::value));
-    // Cast to the base.  This is probably not necessary, but it protects us
-    // from users inheriting from ScriptableNativeObject but then hiding the
-    // GetScriptingBridge function that we want.
-    SharedScriptableNativeObject sno =
-        boost::static_pointer_cast<ScriptableNativeObject>(native_object);
-    WeakScriptingBridge weak_bridge = native_object->GetScriptingBridge();
-    // Try to lock the weak pointer to a shared pointer.  If this succeeds, then
-    // the scripting bridge still exists, and we can set this variant to point
-    // at it.
-    SharedScriptingInterface shared_scripting_if(weak_bridge.lock());
-    if (shared_scripting_if) {
-      // We were able to lock the pointer, so set our internal variant to it.
-      value_ = shared_scripting_if;
-    } else {
-      // We failed to lock a shared_ptr, which means the ScriptingBridge for
-      // this object has gone away.  This must be because the browser is done
-      // with it.  Set the Variant to kNullVariantType to indicate failure.
-      variant_type_ = kNullVariantType;
-    }
-  }
-
-  // TODO(dspringer,dmichael): It might be worthwhile to make a no-copy
-  // version of the std::string ctor variant(), but that requires a lot more
-  // thought.  For reference, see, e.g. CFStringCreateWithCharactersNoCopy()
-  // here:
-  // http://developer.apple.com/library/mac/#documentation/CoreFoundation
-  //     /Reference/CFStringRef/Reference/reference.html
-  // static Variant* CreateWithStringNoCopy(const std::string* string_value);
-
-  // The dtor potentially does a round-trip to the browser in the event that
-  // the underlying storage type is ref counted.
-  virtual ~Variant();
-
-  VariantType variant_type() const {
-    return variant_type_;
-  }
-
-  // Always succeeds.  Conversion rules:
-  //  Convert from higher precision to lower (e.g. double to int): the
-  //    higher precision value is truncated towards 0.
-  //  Convert number to string: the formatted equivalent of printf() with %d or
-  //    %g is used.
-  //  Convert bool to number: true -> 1, false -> 0.
-  //  Convert number to bool: non-0 -> true, 0 within epsilon -> false.
-  //  Convert bool to string: true -> "true", false -> "false".
-  //  Convert string to bool: if the string starts with 't', 'y' or '1' (case
-  //    insensitive) -> true; if it starts with anything else -> false.
-  //  Convert string to number: any format recognized by strol() or strtod()
-  //    (see the POSIX man mages for these functions for more details) is
-  //    converted to a corresponding numeric value; strings that cannot be
-  //    converted this way produce a 0 (the double value is exactly 0.0).
-  template <class T>
-  T GetValue() const {
-    ConvertingVisitor<T> visitor;
-    return boost::apply_visitor(visitor, value_);
-  }
-
-  // Convenience wrappers.
-  bool BoolValue() const {
-    return GetValue<bool>();
-  }
-  int32_t Int32Value() const {
-    return GetValue<int32_t>();
-  }
-  double DoubleValue() const {
-    return GetValue<double>();
-  }
-  std::string StringValue() const {
-    return GetValue<std::string>();
-  }
-  SharedScriptingInterface ObjectValue() const {
-    return GetValue<SharedScriptingInterface>();
-  }
-
-  // TODO(dspringer, dmichael): Add other more specific accessors that give
-  // more information about possible conversions and conversion errors.
-  /*
-  template <class T>
-  T GetValue(bool* did_convert) const;
-  */
-
-  friend bool operator==(const Variant&, const Variant&);
-
- private:
-  VariantType variant_type_;
-  boost::variant<bool,
-                 int32_t,
-                 double,
-                 std::string,
-                 SharedScriptingInterface> value_;
-  // Variants are immutable.  You can copy them, but assignment is not
-  // allowed.
-  Variant& operator=(const Variant&);  // Not implemented, do not use.
-};
-
-}  // namespace c_salt
-
-#endif  // C_SALT_VARIANT_H_