1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/content/base/src/nsAttrValueOrString.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,62 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this file,
1.7 + * You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +/*
1.10 + * A wrapper to contain either an nsAttrValue or an nsAString. This is useful
1.11 + * because constructing an nsAttrValue from an nsAString can be expensive when
1.12 + * the buffer of the string is not shared.
1.13 + *
1.14 + * Since a raw pointer to the passed-in string is kept, this class should only
1.15 + * be used on the stack.
1.16 + */
1.17 +
1.18 +#ifndef nsAttrValueOrString_h___
1.19 +#define nsAttrValueOrString_h___
1.20 +
1.21 +#include "nsString.h"
1.22 +#include "nsAttrValue.h"
1.23 +
1.24 +class MOZ_STACK_CLASS nsAttrValueOrString
1.25 +{
1.26 +public:
1.27 + nsAttrValueOrString(const nsAString& aValue)
1.28 + : mAttrValue(nullptr)
1.29 + , mStringPtr(&aValue)
1.30 + , mCheapString(nullptr)
1.31 + { }
1.32 + nsAttrValueOrString(const nsAttrValue& aValue)
1.33 + : mAttrValue(&aValue)
1.34 + , mStringPtr(nullptr)
1.35 + , mCheapString(nullptr)
1.36 + { }
1.37 +
1.38 + /**
1.39 + * Returns a reference to the string value of the contents of this object.
1.40 + *
1.41 + * When this object points to a string or an nsAttrValue of string or atom
1.42 + * type this should be fairly cheap. Other nsAttrValue types will be
1.43 + * serialized the first time this is called and cached from thereon.
1.44 + */
1.45 + const nsAString& String() const;
1.46 +
1.47 + /**
1.48 + * Compares the string representation of this object with the string
1.49 + * representation of an nsAttrValue.
1.50 + */
1.51 + bool EqualsAsStrings(const nsAttrValue& aOther) const
1.52 + {
1.53 + if (mStringPtr) {
1.54 + return aOther.Equals(*mStringPtr, eCaseMatters);
1.55 + }
1.56 + return aOther.EqualsAsStrings(*mAttrValue);
1.57 + }
1.58 +
1.59 +protected:
1.60 + const nsAttrValue* mAttrValue;
1.61 + mutable const nsAString* mStringPtr;
1.62 + mutable nsCheapString mCheapString;
1.63 +};
1.64 +
1.65 +#endif // nsAttrValueOrString_h___
