From 36d22d82aa202bb199967e9512281e9a53db42c9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 21:33:14 +0200 Subject: Adding upstream version 115.7.0esr. Signed-off-by: Daniel Baumann --- dom/base/nsAttrValueOrString.h | 85 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100644 dom/base/nsAttrValueOrString.h (limited to 'dom/base/nsAttrValueOrString.h') diff --git a/dom/base/nsAttrValueOrString.h b/dom/base/nsAttrValueOrString.h new file mode 100644 index 0000000000..9cb3db33c5 --- /dev/null +++ b/dom/base/nsAttrValueOrString.h @@ -0,0 +1,85 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this file, + * You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/* + * A wrapper to contain either an nsAttrValue or an nsAString. This is useful + * because constructing an nsAttrValue from an nsAString can be expensive when + * the buffer of the string is not shared. + * + * This treats nsAttrValueOrString(nullptr) as the empty string, + * to help with contexts where a null pointer denotes an empty value. + * + * Since a raw pointer to the passed-in string is kept, this class should only + * be used on the stack. + */ + +#ifndef nsAttrValueOrString_h___ +#define nsAttrValueOrString_h___ + +#include "nsString.h" +#include "nsAttrValue.h" + +class MOZ_STACK_CLASS nsAttrValueOrString { + public: + explicit nsAttrValueOrString(const nsAString& aValue) + : mAttrValue(nullptr), mStringPtr(&aValue), mCheapString(nullptr) {} + + explicit nsAttrValueOrString(const nsAString* aValue) + : mAttrValue(nullptr), mStringPtr(aValue), mCheapString(nullptr) {} + + explicit nsAttrValueOrString(const nsAttrValue& aValue) + : mAttrValue(&aValue), mStringPtr(nullptr), mCheapString(nullptr) {} + + explicit nsAttrValueOrString(const nsAttrValue* aValue) + : mAttrValue(aValue), mStringPtr(nullptr), mCheapString(nullptr) {} + + void ResetToAttrValue(const nsAttrValue& aValue) { + mAttrValue = &aValue; + mStringPtr = nullptr; + // No need to touch mCheapString here. If we need to use it, we will reset + // it to the rigthe value anyway. + } + + /** + * Returns a reference to the string value of the contents of this object. + * + * When this object points to a string or an nsAttrValue of string or atom + * type this should be fairly cheap. Other nsAttrValue types will be + * serialized the first time this is called and cached from thereon. + */ + const nsAString& String() const; + + /** + * Compares the string representation of this object with the string + * representation of an nsAttrValue. + */ + bool EqualsAsStrings(const nsAttrValue& aOther) const { + if (mStringPtr) { + return aOther.Equals(*mStringPtr, eCaseMatters); + } + return aOther.EqualsAsStrings(*mAttrValue); + } + + /* + * Returns true if the value stored is empty + */ + bool IsEmpty() const { + if (mStringPtr) { + return mStringPtr->IsEmpty(); + } + if (mAttrValue) { + return mAttrValue->IsEmptyString(); + } + return true; + } + + protected: + const nsAttrValue* mAttrValue; + mutable const nsAString* mStringPtr; + mutable nsCheapString mCheapString; +}; + +#endif // nsAttrValueOrString_h___ -- cgit v1.2.3