[Qt][Win] Fix UString related build problem in Source/WebCore/bridge/qt/qt_instance.cpp

[Csaba Osztrogonác]

Source/WebCore/bridge/qt/qt_instance.cpp doesn't build
because of some UString related problem. (Details are coming soon.)

[Csaba Osztrogonác]

Error log:
f:\WebKit\Source\WebCore\bridge\qt\qt_instance.cpp(242) : error C2665: 'JSC::UString::UString' : none of the 11 overloads could convert all the argument types
        f:\webkit\source\javascriptcore\runtime\UString.h(36): could be 'JSC::UString::UString(const UChar *,unsigned int)'
        f:\webkit\source\javascriptcore\runtime\UString.h(42): or       'JSC::UString::UString(const LChar *,unsigned int)'
        f:\webkit\source\javascriptcore\runtime\UString.h(43): or       'JSC::UString::UString(const char *,unsigned int)'
        while trying to match the argument list '(const ushort *, int)'

qt_instance.cpp: 
-----------------
240: #if HAVE(QT5)
241:     QString sig = QString::fromLatin1(method.methodSignature());
242:     array.add(Identifier(exec, UString(sig.utf16(), sig.length())));
243: #else
244:     array.add(Identifier(exec, method.signature()));
245: #endif

Qstring.utf16() returns with const ushort * on all platform, but it works
fine on Linux 32/64 bit too. Maybe the sizeof(ushort) is different on win.

[Csaba Osztrogonác]

Created attachment 145782 [details]
Patch

It's only a speculative fix, I'm not sure if it is proper or not. Could you confirm if I'm on good or bad way?

[Simon Hausmann]

Comment on attachment 145782 [details]
Patch

So what's happening here is that method.methodSignature() returns a QByteArray (latin1 encoded string), that is converted to a utf-16 encoded QString, which is then supposed to get converted to a UString - except that the compiler is confused.

Fortunately UString supports also latin1 encoded 8-bit strings, so I think the much simpler fix is to avoid conversion from 8-bit latin1 to utf-16 and instead construct the UString straight from 8-bit, i.e.
    QByteArray sig = method.methodSignature();
    .... UString(sig.constData(), sig.length());

[Csaba Osztrogonác]

Created attachment 146260 [details]
Patch

fixed patch

[Early Warning System Bot]

Comment on attachment 146260 [details]
Patch

Attachment 146260 [details] did not pass qt-wk2-ews (qt):
Output: http://queues.webkit.org/results/12913198

[Csaba Osztrogonác]

Created attachment 146261 [details]
Patch

typo fixed

[Early Warning System Bot]

Comment on attachment 146261 [details]
Patch

Attachment 146261 [details] did not pass qt-wk2-ews (qt):
Output: http://queues.webkit.org/results/12920154

[Csaba Osztrogonác]

Created attachment 146264 [details]
Patch

typo fixed - 2nd attempt

[Csaba Osztrogonác]

Created attachment 146265 [details]
Patch

typo fixed - 3rd attempt. It's not my day. :)

[Early Warning System Bot]

Comment on attachment 146265 [details]
Patch

Attachment 146265 [details] did not pass qt-wk2-ews (qt):
Output: http://queues.webkit.org/results/12922134

[Csaba Osztrogonác]

Comment on attachment 146265 [details]
Patch

It isn't my day. :( I'll try again once I'm in a better shape ...

[Csaba Osztrogonác]

Kent updated this part of code after renaming by http://trac.webkit.org/changeset/116102 (and reviewed by Tor Arne)

96f2365cf4cebc074c3171878dcd25ce19ee7486 was "Rename QMetaMethod::signature() to methodSignature()" in Qt5/qtbase

I've lost the labyrinth of QString/QByteArray/latin1/utf8/utf16 things,
I can't fix it myself, I gave it up. :(

Could you guys pick up this bug?

[Csaba Osztrogonác]

Created attachment 146285 [details]
Patch

It is my last attempt. I can't copy/paste anything today ... :-/

[Csaba Osztrogonác]

Comment on attachment 146285 [details]
Patch

Clearing flags on attachment: 146285

Committed r119969: <http://trac.webkit.org/changeset/119969>

[Csaba Osztrogonác]

All reviewed patches have been landed.  Closing bug.