Add QString<->emscripten::val conversion functions

Following the QRect, add functions converting the QString to native
emscripten::val and back: fromJsString, toJsString

Change-Id: I2d0625ede3bbf7249e2e91b8de298b5b91df8ba2
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

src/corelib/kernel/qcore_wasm.cpp

@@ -42,4 +42,56 @@ emscripten::val QRectF::toDOMRect() const
     return emscripten::val::global("DOMRect").new_(left(), top(), width(), height());
 }
 
+/*!
+    Converts the \l {https://262.ecma-international.org/#sec-string-object}{ECMAScript string} \a
+    jsString to QString. Behavior is undefined if the provided parameter is not a string.
+
+    \since 6.6
+    \ingroup platform-type-conversions
+
+    \sa toJsString()
+*/
+QString QString::fromJsString(emscripten::val jsString)
+{
+    Q_ASSERT_X(jsString.isString(), Q_FUNC_INFO, "Passed object is not a string");
+
+    const double length = jsString["length"].as<double>();
+
+    Q_ASSERT_X((double(uint64_t(length)) != double(uint64_t(length) - 1)
+                && double(uint64_t(length)) != double(uint64_t(length) + 1))
+                       || !std::numeric_limits<double>::is_iec559,
+               Q_FUNC_INFO, "The floating-point length cannot precisely represent an integer");
+
+    constexpr int zeroTerminatorLength = 1;
+    const auto lengthOfUtf16 = (length + zeroTerminatorLength) * 2;
+
+    Q_ASSERT_X((double(uint64_t(lengthOfUtf16)) != double(uint64_t(lengthOfUtf16) - 1)
+                && double(uint64_t(lengthOfUtf16)) != double(uint64_t(lengthOfUtf16) + 1))
+                       || !std::numeric_limits<double>::is_iec559,
+               Q_FUNC_INFO,
+               "The floating-point lengthOfUtf16 cannot precisely represent an integer");
+
+    const QString result(uint64_t(length), Qt::Uninitialized);
+
+    static const emscripten::val stringToUTF16(emscripten::val::module_property("stringToUTF16"));
+    stringToUTF16(jsString, emscripten::val(quintptr(result.data())),
+                  emscripten::val(lengthOfUtf16));
+    return result;
+}
+
+/*!
+    Converts this object to an
+    \l {https://262.ecma-international.org/#sec-string-object}{ECMAScript string}.
+
+    \since 6.6
+    \ingroup platform-type-conversions
+
+    \sa fromJsString()
+*/
+emscripten::val QString::toJsString() const
+{
+    static const emscripten::val UTF16ToString(emscripten::val::module_property("UTF16ToString"));
+    return UTF16ToString(emscripten::val(quintptr(utf16())));
+}
+
 QT_END_NAMESPACE

src/corelib/text/qstring.h

@@ -806,6 +806,11 @@ public:
     NSString *toNSString() const Q_DECL_NS_RETURNS_AUTORELEASED;
 #endif
 
+#if defined(Q_OS_WASM) || defined(Q_QDOC)
+    static QString fromJsString(emscripten::val jsString);
+    emscripten::val toJsString() const;
+#endif
+
     inline bool isNull() const { return d->isNull(); }
 
 

src/plugins/platforms/wasm/CMakeLists.txt

@@ -31,7 +31,6 @@ qt_internal_add_plugin(QWasmIntegrationPlugin
         qwasmplatform.cpp qwasmplatform.h
         qwasmscreen.cpp qwasmscreen.h
         qwasmservices.cpp qwasmservices.h
-        qwasmstring.cpp qwasmstring.h
         qwasmstylepixmaps_p.h
         qwasmtheme.cpp qwasmtheme.h
         qwasmwindow.cpp qwasmwindow.h

src/plugins/platforms/wasm/qwasmclipboard.cpp

@@ -3,7 +3,7 @@
 
 #include "qwasmclipboard.h"
 #include "qwasmwindow.h"
-#include "qwasmstring.h"
+
 #include <private/qstdweb_p.h>
 
 #include <emscripten.h>
@@ -27,12 +27,11 @@ static void commonCopyEvent(val event)
 
     // doing it this way seems to sanitize the text better that calling data() like down below
     if (_mimes->hasText()) {
-        event["clipboardData"].call<void>("setData", val("text/plain")
-                                          ,  QWasmString::fromQString(_mimes->text()));
+        event["clipboardData"].call<void>("setData", val("text/plain"),
+                                          _mimes->text().toJsString());
     }
     if (_mimes->hasHtml()) {
-        event["clipboardData"].call<void>("setData", val("text/html")
-                                          ,   QWasmString::fromQString(_mimes->html()));
+        event["clipboardData"].call<void>("setData", val("text/html"), _mimes->html().toJsString());
     }
 
     for (auto mimetype : _mimes->formats()) {
@@ -40,8 +39,8 @@ static void commonCopyEvent(val event)
             continue;
         QByteArray ba = _mimes->data(mimetype);
         if (!ba.isEmpty())
-            event["clipboardData"].call<void>("setData", QWasmString::fromQString(mimetype)
-                                              , val(ba.constData()));
+            event["clipboardData"].call<void>("setData", mimetype.toJsString(),
+                                              val(ba.constData()));
     }
 
     event.call<void>("preventDefault");
@@ -140,7 +139,7 @@ static void qClipboardPasteTo(val dataTransfer)
                 || itemMimeType.contains("TEXT", Qt::CaseSensitive)) {
                 break;
             }
-            const QString data = QWasmString::toQString(
+            const QString data = QString::fromJsString(
                     clipboardData.call<val>("getData", val(itemMimeType.toStdString())));
 
             if (!data.isEmpty()) {
@@ -329,12 +328,12 @@ void QWasmClipboard::writeToClipboardApi()
 
         // we have a blob, now create a ClipboardItem
         emscripten::val type = emscripten::val::array();
-        type.set("type", val(QWasmString::fromQString(mimetype)));
+        type.set("type", mimetype.toJsString());
 
         emscripten::val contentBlob = emscripten::val::global("Blob").new_(contentArray, type);
 
         emscripten::val clipboardItemObject = emscripten::val::object();
-        clipboardItemObject.set(val(QWasmString::fromQString(mimetype)), contentBlob);
+        clipboardItemObject.set(mimetype.toJsString(), contentBlob);
 
         val clipboardItemData = val::global("ClipboardItem").new_(clipboardItemObject);
 

src/plugins/platforms/wasm/qwasmcursor.cpp

@@ -3,7 +3,6 @@
 
 #include "qwasmcursor.h"
 #include "qwasmscreen.h"
-#include "qwasmstring.h"
 
 #include <QtCore/qdebug.h>
 #include <QtGui/qwindow.h>

src/plugins/platforms/wasm/qwasmeventtranslator.cpp

@@ -6,7 +6,6 @@
 #include "qwasmcompositor.h"
 #include "qwasmintegration.h"
 #include "qwasmclipboard.h"
-#include "qwasmstring.h"
 #include "qwasmcursor.h"
 #include <QtGui/qevent.h>
 #include <qpa/qwindowsysteminterface.h>

src/plugins/platforms/wasm/qwasmintegration.cpp

@@ -11,7 +11,6 @@
 #include "qwasmaccessibility.h"
 #include "qwasmservices.h"
 #include "qwasmoffscreensurface.h"
-#include "qwasmstring.h"
 
 #include "qwasmwindow.h"
 #include "qwasmbackingstore.h"
@@ -287,7 +286,8 @@ void QWasmIntegration::removeScreen(const emscripten::val &element)
     auto it = std::find_if(m_screens.begin(), m_screens.end(),
         [&] (const QPair<emscripten::val, QWasmScreen *> &candidate) { return candidate.first.equals(element); });
     if (it == m_screens.end()) {
-        qWarning() << "Attempting to remove non-existing screen for element" << QWasmString::toQString(element["id"]);;
+        qWarning() << "Attempting to remove non-existing screen for element"
+                   << QString::fromJsString(element["id"]);
         return;
     }
     it->second->deleteScreen();
@@ -299,7 +299,8 @@ void QWasmIntegration::resizeScreen(const emscripten::val &element)
     auto it = std::find_if(m_screens.begin(), m_screens.end(),
         [&] (const QPair<emscripten::val, QWasmScreen *> &candidate) { return candidate.first.equals(element); });
     if (it == m_screens.end()) {
-        qWarning() << "Attempting to resize non-existing screen for element" << QWasmString::toQString(element["id"]);;
+        qWarning() << "Attempting to resize non-existing screen for element"
+                   << QString::fromJsString(element["id"]);
         return;
     }
     it->second->updateQScreenAndCanvasRenderSize();

src/plugins/platforms/wasm/qwasmscreen.cpp

@@ -6,7 +6,6 @@
 #include "qwasmeventtranslator.h"
 #include "qwasmcompositor.h"
 #include "qwasmintegration.h"
-#include "qwasmstring.h"
 #include "qwasmcssstyle.h"
 
 #include <emscripten/bind.h>
@@ -194,7 +193,7 @@ qreal QWasmScreen::devicePixelRatio() const
 
 QString QWasmScreen::name() const
 {
-    return QWasmString::toQString(m_shadowContainer["id"]);
+    return QString::fromJsString(m_shadowContainer["id"]);
 }
 
 QPlatformCursor *QWasmScreen::cursor() const

src/plugins/platforms/wasm/qwasmservices.cpp

@@ -2,7 +2,6 @@
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
 
 #include "qwasmservices.h"
-#include "qwasmstring.h"
 
 #include <QtCore/QUrl>
 #include <QtCore/QDebug>
@@ -13,8 +12,8 @@ QT_BEGIN_NAMESPACE
 
 bool QWasmServices::openUrl(const QUrl &url)
 {
-    emscripten::val jsUrl = QWasmString::fromQString(url.toString());
-    emscripten::val::global("window").call<void>("open", jsUrl, emscripten::val("_blank"));
+    emscripten::val::global("window").call<void>("open", url.toString().toJsString(),
+                                                 emscripten::val("_blank"));
     return true;
 }
 

src/plugins/platforms/wasm/qwasmstring.cpp

@@ -1,36 +0,0 @@
-// Copyright (C) 2020 The Qt Company Ltd.
-// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
-
-#include "qwasmstring.h"
-
-QT_BEGIN_NAMESPACE
-
-using namespace emscripten;
-
-val QWasmString::fromQString(const QString &str)
-{
-    static const val UTF16ToString(
-        val::module_property("UTF16ToString"));
-
-    auto ptr = quintptr(str.utf16());
-    return UTF16ToString(val(ptr));
-}
-
-QString QWasmString::toQString(const val &v)
-{
-    QString result;
-    if (!v.isString())
-        return result;
-
-    static const val stringToUTF16(
-        val::module_property("stringToUTF16"));
-    static const val length("length");
-
-    int len = v[length].as<int>();
-    result.resize(len);
-    auto ptr = quintptr(result.utf16());
-    stringToUTF16(v, val(ptr), val((len + 1) * 2));
-    return result;
-}
-
-QT_END_NAMESPACE

src/plugins/platforms/wasm/qwasmstring.h

@@ -1,19 +0,0 @@
-// Copyright (C) 2020 The Qt Company Ltd.
-// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only
-
-#pragma once
-
-#include <qstring.h>
-
-#include <emscripten/val.h>
-
-QT_BEGIN_NAMESPACE
-
-class QWasmString
-{
-public:
-    static emscripten::val fromQString(const QString &str);
-    static QString toQString(const emscripten::val &v);
-};
-QT_END_NAMESPACE
-

src/plugins/platforms/wasm/qwasmwindow.cpp

@@ -18,7 +18,6 @@
 #include "qwasmcompositor.h"
 #include "qwasmevent.h"
 #include "qwasmeventdispatcher.h"
-#include "qwasmstring.h"
 #include "qwasmaccessibility.h"
 
 #include <iostream>

tests/auto/corelib/text/qstring/CMakeLists.txt

@@ -9,6 +9,9 @@ if(APPLE)
     list(APPEND tst_qstring_extra_libraries ${FWFoundation})
     list(APPEND tst_qstring_extra_sources tst_qstring_mac.mm)
 endif()
+if(WASM)
+    list(APPEND tst_qstring_extra_sources tst_qstring_wasm.cpp)
+endif()
 
 foreach(test tst_qstring tst_qstring_restricted_ascii)
     qt_internal_add_test(${test}

tests/auto/corelib/text/qstring/tst_qstring.cpp

@@ -541,6 +541,7 @@ private slots:
 #endif
     void STL();
     void macTypes();
+    void wasmTypes();
     void isEmpty();
     void isNull();
     void nullness();
@@ -1344,6 +1345,16 @@ void tst_QString::macTypes()
 #endif
 }
 
+void tst_QString::wasmTypes()
+{
+#ifndef Q_OS_WASM
+    QSKIP("This is a WASM-only test");
+#else
+    extern void tst_QString_wasmTypes(); // in qcore_wasm.cpp
+    tst_QString_wasmTypes();
+#endif
+}
+
 void tst_QString::truncate()
 {
     QString nullStr;

tests/auto/corelib/text/qstring/tst_qstring_wasm.cpp

@@ -0,0 +1,28 @@
+// Copyright (C) 2016 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#include <QtCore/QString>
+#include <QTest>
+
+#include <emscripten/val.h>
+
+void tst_QString_wasmTypes()
+{
+    // QString <-> emscripten::val
+    {
+        QString qtString("test string");
+        const emscripten::val jsString = qtString.toJsString();
+        QString qtStringCopy(qtString);
+        qtString = qtString.toUpper(); // modify
+        QCOMPARE(QString::fromJsString(jsString), qtStringCopy);
+    }
+    {
+        QString longString;
+        for (uint64_t i = 0; i < 1000; ++i)
+            longString += "Lorem ipsum FTW";
+        const emscripten::val jsString = longString.toJsString();
+        QString qtStringCopy(longString);
+        longString = longString.toUpper(); // modify
+        QCOMPARE(QString::fromJsString(jsString), qtStringCopy);
+    }
+}