• zimmermann@webkit.org's avatar
    2011-05-12 Nikolas Zimmermann <nzimmermann@rim.com> · 6da15387
    zimmermann@webkit.org authored
            Reviewed by Darin Adler.
    
            String operator+ reallocates unnecessarily when concatting > 2 strings
            https://bugs.webkit.org/show_bug.cgi?id=58420
    
            Provide a faster String append operator.
            Up until now, "String operator+(const String& a, const String& b)" copied String a into a temporary
            object, and used a.append(b), which reallocates a new buffer of aLength+bLength. When concatting
            N strings using operator+, this leads to N-1 reallocations.
    
            Replace this with a flexible operator+ implementation, that avoids these reallocations.
            When concatting a 'String' with any string type (char*, UChar, Vector<char>, String, AtomicString, etc..)
            a StringAppend<String, T> object is created, which holds the intermediate string objects, and delays
            creation of the final string, until operator String() is invoked.
    
            template<typename T>
            StringAppend<String, T> operator+(const String& string1, T string2)
            {
                return StringAppend<String, T>(string1, string2);
            }
    
            template<typename U, typename V, typename W>
            StringAppend<U, StringAppend<V, W> > operator+(U string1, const StringAppend<V, W>& string2)
            {
                return StringAppend<U, StringAppend<V, W> >(string1, string2);
            }
    
            When concatting three strings - "String a, b, c; String result = a + b + c;" following happens:
            first a StringAppend<String, String> object is created by operator+(const String& string1, String string2).
            Then operator+(String string1, const StringAppend<String, String>& string2) is invoked, which returns
            a StringAppend<String, StringAppend<String, String> > object.
            Then operator String() is invoked, which allocates a StringImpl object, once, large enough to hold the
            final string - it uses tryMakeString provided by StringConcatenate.h under the hoods, which guards us
            against too big string allocations, etc.
    
            Note that the second template, defines a recursive way to concat an arbitary number of strings
            into a single String with just one allocation.
    
            * GNUmakefile.list.am: Add StringOperators.h to build.
            * JavaScriptCore.exp: Export WTF::emptyString(). Remove no longer needed symbols.
            * JavaScriptCore.gypi: Add StringOperators.h to build.
            * JavaScriptCore.vcproj/WTF/WTF.vcproj: Ditto.
            * JavaScriptCore.xcodeproj/project.pbxproj: Ditto.
            * wtf/text/AtomicString.h: Pull in StringConcatenate.h at the end of the file.
            * wtf/text/StringConcatenate.h: Conditionally include AtomicString.h to avoid a cyclic dependency. Pull in StringOperators.h at the end of the file.
            * wtf/text/StringOperators.h: Added. This is never meant to be included directly, including either WTFString.h or AtomicString.h automatically pulls in this file.
            (WTF::StringAppend::StringAppend):
            (WTF::StringAppend::operator String):
            (WTF::StringAppend::operator AtomicString):
            (WTF::StringAppend::writeTo):
            (WTF::StringAppend::length):
            (WTF::operator+):
            * wtf/text/WTFString.cpp: Remove operator+ implementations that use String::append(). 
            (WTF::emptyString): Add new shared empty string free function.
            * wtf/text/WTFString.h: Replace operator+ implementations by StringAppend template solution. Pull in AtomicString.h at the end of the file.
    
    2011-05-12  Nikolas Zimmermann  <nzimmermann@rim.com>
    
            Reviewed by Darin Adler.
    
            String operator+ reallocates unnecessary when concatting > 2 strings
            https://bugs.webkit.org/show_bug.cgi?id=58420
    
            Provide a faster String append operator. See Source/JavaScriptCore/ChangeLog for details.
    
            * dom/XMLDocumentParserLibxml2.cpp:
            (WebCore::handleElementAttributes):
            * editing/MarkupAccumulator.cpp:
            (WebCore::MarkupAccumulator::shouldAddNamespaceElement):
            * html/HTMLAnchorElement.cpp:
            (WebCore::HTMLAnchorElement::hash):
            (WebCore::HTMLAnchorElement::search):
            * html/ImageInputType.cpp:
            (WebCore::ImageInputType::appendFormData):
            * html/parser/HTMLTreeBuilder.cpp:
            * loader/CrossOriginAccessControl.cpp:
            (WebCore::passesAccessControlCheck):
            * page/Location.cpp:
            (WebCore::Location::search):
            (WebCore::Location::hash):
            * page/NavigatorBase.cpp:
            (WebCore::NavigatorBase::platform):
            * platform/chromium/ClipboardChromium.cpp:
            (WebCore::writeImageToDataObject):
            * platform/gtk/PasteboardHelper.cpp:
            (WebCore::PasteboardHelper::fillSelectionData):
            * platform/network/cf/ResourceHandleCFNet.cpp:
            (WebCore::encodeBasicAuthorization):
            * platform/network/cf/SocketStreamHandleCFNet.cpp:
            (WebCore::SocketStreamHandle::copyCFStreamDescription):
            * platform/network/mac/ResourceHandleMac.mm:
            (WebCore::encodeBasicAuthorization):
            * workers/WorkerLocation.cpp:
            (WebCore::WorkerLocation::search):
            (WebCore::WorkerLocation::hash):
    
    2011-05-12  Nikolas Zimmermann  <nzimmermann@rim.com>
    
            Reviewed by Darin Adler.
    
            String operator+ reallocates unnecessarily when concatting > 2 strings
            https://bugs.webkit.org/show_bug.cgi?id=58420
    
            Provide a faster String append operator. See Source/JavaScriptCore/ChangeLog for details.
    
            * src/WebAccessibilityObject.cpp:
            (WebKit::WebAccessibilityObject::keyboardShortcut): Cast to String first, before trying to convert to platform dependant type.
            * src/WebHTTPLoadInfo.cpp:
            (WebKit::addHeader): Don't pass WebString to makeString, explicit cast to String first.
            * tests/IDBLevelDBCodingTest.cpp: Cast to String first, to avoid conflicting with gtests global templatified operator+.
            (IDBLevelDBCoding::TEST):
    
    2011-05-12  Nikolas Zimmermann  <nzimmermann@rim.com>
    
            Reviewed by Darin Adler.
    
            String operator+ reallocates unnecessarily when concatting > 2 strings
            https://bugs.webkit.org/show_bug.cgi?id=58420
    
            Provide a faster String append operator. See Source/JavaScriptCore/ChangeLog for details.
    
            * WebView/WebFrame.mm: Explicitely cast to Strings first, so operator NSString*() can be invoked.
            (-[WebFrame _stringWithDocumentTypeStringAndMarkupString:]):
    
    2011-05-12  Nikolas Zimmermann  <nzimmermann@rim.com>
    
            Reviewed by Darin Adler.
    
            String operator+ reallocates unnecessarily when concatting > 2 strings
            https://bugs.webkit.org/show_bug.cgi?id=58420
    
            Provide a faster String append operator. See Source/JavaScriptCore/ChangeLog for details.
    
            * AccessibleBase.cpp:
            (AccessibleBase::get_accKeyboardShortcut): Explicitely cast to Strings first, so operator BString() can be invoked.
    
    
    git-svn-id: http://svn.webkit.org/repository/webkit/trunk@86330 268f45cc-cd09-0410-ab3c-d52691b4dbfc
    6da15387
JavaScriptCore.exp 24.7 KB