Salvage #13772

res/controllers/engine-api.d.ts

@@ -301,4 +301,35 @@ declare namespace engine {
      *               SoftStart with low factors would take a while until sound is audible. [default = 1.0]
      */
     function softStart(deck: number, activate: boolean, factor?: number): void;
+
+    enum WellKnownCharsets {
+        US_ASCII,
+        Latin1,
+        ISO_8859_1,
+        Latin9,
+        ISO_8859_15,
+        UCS2, // with prepended Byte-Order-Mark
+        ISO_10646_UCS_2, // with prepended Byte-Order-Mark
+        UTF_8,
+        UTF_16BE,
+        UTF_16LE,
+    }
+
+    /**
+     * Converts a string into another charset.
+     *
+     * This function is useful to display text on a device that does not make use of UTF-8.
+     * Available charset names are listed here: http://www.iana.org/assignments/character-sets/character-sets.xhtml.
+     * Characters that are unsupported by target charset will be transformed to null character (0x00).
+     * @param targetCharset The charset to encode the string into.
+     * @param value The string to encode
+     * @returns The converted String as an array of bytes. Will return an empty buffer on conversion error or unavailable charset.
+     */
+    function convertCharset(targetCharset: string, value: string): ArrayBuffer
+
+    /**
+     * @param value The string to encode
+     * @returns The converted String as an array of bytes. Will return an empty buffer on conversion error or unavailable charset.
+     */
+    function convertCharset(targetCharset: WellKnownCharsets, value: string): ArrayBuffer
 }

src/controllers/scripting/legacy/controllerscriptenginelegacy.cpp

@@ -338,8 +338,10 @@ bool ControllerScriptEngineLegacy::initialize() {
     ControllerScriptInterfaceLegacy* legacyScriptInterface =
             new ControllerScriptInterfaceLegacy(this, m_logger);
 
-    engineGlobalObject.setProperty(
-            "engine", m_pJSEngine->newQObject(legacyScriptInterface));
+    auto engine = m_pJSEngine->newQObject(legacyScriptInterface);
+    auto meta = m_pJSEngine->newQMetaObject(&ControllerScriptInterfaceLegacy::staticMetaObject);
+    engine.setProperty("WellKnownCharsets", meta);
+    engineGlobalObject.setProperty("engine", m_pJSEngine->newQObject(legacyScriptInterface));
 
 #ifdef MIXXX_USE_QML
     if (m_bQmlMode) {

src/controllers/scripting/legacy/controllerscriptinterfacelegacy.cpp

@@ -1,5 +1,10 @@
 #include "controllerscriptinterfacelegacy.h"
 
+#if QT_VERSION < QT_VERSION_CHECK(6, 4, 0)
+#include <QTextCodec>
+#else
+#include <QStringEncoder>
+#endif
 #include <gsl/pointers>
 
 #include "control/controlobject.h"
@@ -1052,3 +1057,45 @@ void ControllerScriptInterfaceLegacy::softStart(int deck, bool activate, double
     // activate the ramping in scratchProcess()
     m_ramp[deck] = true;
 }
+
+QByteArray ControllerScriptInterfaceLegacy::convertCharset(
+        const ControllerScriptInterfaceLegacy::WellKnownCharsets targetCharset,
+        const QString& value) {
+    switch (targetCharset) {
+    case WellKnownCharsets::US_ASCII:
+        return convertCharsetInternal(QStringLiteral("US-ASCII"), value);
+    case WellKnownCharsets::Latin1:
+    case WellKnownCharsets::ISO_8859_1:
+        return convertCharsetInternal(QStringLiteral("ISO-8859-1"), value);
+    case WellKnownCharsets::Latin9:
+    case WellKnownCharsets::ISO_8859_15:
+        return convertCharsetInternal(QStringLiteral("ISO-8859-15"), value);
+    case WellKnownCharsets::UCS2:
+    case WellKnownCharsets::ISO_10646_UCS_2:
+        return convertCharsetInternal(QStringLiteral("ISO-10646-UCS-2"), value);
+    case WellKnownCharsets::UTF_8:
+        return convertCharsetInternal(QStringLiteral("UTF-8"), value);
+    case WellKnownCharsets::UTF_16BE:
+        return convertCharsetInternal(QStringLiteral("UTF-16BE"), value);
+    case WellKnownCharsets::UTF_16LE:
+        return convertCharsetInternal(QStringLiteral("UTF-16LE"), value);
+    }
+    m_pScriptEngineLegacy->logOrThrowError(QStringLiteral("Unknown charset specified"));
+    return QByteArray();
+}
+
+QByteArray ControllerScriptInterfaceLegacy::convertCharsetInternal(
+        const QString& targetCharset, const QString& value) {
+#if QT_VERSION >= QT_VERSION_CHECK(6, 8, 0)
+    QAnyStringView encoderName = QAnyStringView(targetCharset);
+#else
+    QByteArray encoderNameArray = targetCharset.toUtf8();
+    const char* encoderName = encoderNameArray.constData();
+#endif
+    QStringEncoder fromUtf16 = QStringEncoder(encoderName);
+    if (!fromUtf16.isValid()) {
+        m_pScriptEngineLegacy->logOrThrowError(QStringLiteral("Unable to open encoder"));
+        return QByteArray();
+    }
+    return fromUtf16(value);
+}

src/controllers/scripting/legacy/controllerscriptinterfacelegacy.h

@@ -17,6 +17,20 @@ class ConfigKey;
 class ControllerScriptInterfaceLegacy : public QObject {
     Q_OBJECT
   public:
+    enum class WellKnownCharsets {
+        US_ASCII,
+        Latin1,
+        ISO_8859_1,
+        Latin9,
+        ISO_8859_15,
+        UCS2,
+        ISO_10646_UCS_2,
+        UTF_8,
+        UTF_16BE,
+        UTF_16LE,
+    };
+    Q_ENUM(WellKnownCharsets)
+
     ControllerScriptInterfaceLegacy(ControllerScriptEngineLegacy* m_pEngine,
             const RuntimeLoggingCategory& logger);
 
@@ -72,6 +86,11 @@ class ControllerScriptInterfaceLegacy : public QObject {
             const double rate = -10.0);
     Q_INVOKABLE void softStart(const int deck, bool activate, double factor = 1.0);
 
+    Q_INVOKABLE QByteArray convertCharset(
+            const ControllerScriptInterfaceLegacy::WellKnownCharsets
+                    targetCharset,
+            const QString& value);
+
     bool removeScriptConnection(const ScriptConnection& conn);
     /// Execute a ScriptConnection's JS callback
     void triggerScriptConnection(const ScriptConnection& conn);
@@ -84,6 +103,9 @@ class ControllerScriptInterfaceLegacy : public QObject {
             const QString& name,
             const QJSValue& callback,
             bool skipSuperseded = false);
+
+    QByteArray convertCharsetInternal(const QString& targetCharset, const QString& value);
+
     QHash<ConfigKey, ControlObjectScript*> m_controlCache;
     ControlObjectScript* getControlObjectScript(const QString& group, const QString& name);
 

src/test/controllerscriptenginelegacy_test.cpp

@@ -3,6 +3,8 @@
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 
+#include <QByteArrayView>
+#include <QMetaEnum>
 #include <QScopedPointer>
 #include <QTemporaryFile>
 #include <QThread>
@@ -12,6 +14,7 @@
 
 #include "control/controlobject.h"
 #include "control/controlpotmeter.h"
+#include "controllers/scripting/legacy/controllerscriptinterfacelegacy.h"
 #ifdef MIXXX_USE_QML
 #include <QQuickItem>
 
@@ -658,6 +661,84 @@ TEST_F(ControllerScriptEngineLegacyTest, connectionExecutesWithCorrectThisObject
     EXPECT_DOUBLE_EQ(1.0, pass->get());
 }
 
+TEST_F(ControllerScriptEngineLegacyTest, convertCharsetUndefinedOnUnknownCharset) {
+    const auto result = evaluate("engine.convertCharset('NULL', 'Hello!')");
+
+    EXPECT_EQ(qjsvalue_cast<QByteArray>(result), QByteArrayView(""));
+}
+
+TEST_F(ControllerScriptEngineLegacyTest, convertCharsetCorrectValueWellKnown) {
+    const auto result = evaluate(
+            "engine.convertCharset(engine.WellKnownCharsets.Latin9, 'Hello!')");
+
+    // ISO-8859-15 ecoded 'Hello!'
+    EXPECT_EQ(qjsvalue_cast<QByteArray>(result),
+            QByteArrayView::fromArray({'\x48', '\x65', '\x6c', '\x6c', '\x6f', '\x21'}));
+}
+
+TEST_F(ControllerScriptEngineLegacyTest, convertCharsetCorrectValueStringCharset) {
+    const auto result = evaluate("engine.convertCharset('ISO-8859-15', 'Hello!')");
+
+    // ISO-8859-15 ecoded 'Hello!'
+    EXPECT_EQ(qjsvalue_cast<QByteArray>(result),
+            QByteArrayView::fromArray({'\x48', '\x65', '\x6c', '\x6c', '\x6f', '\x21'}));
+}
+
+TEST_F(ControllerScriptEngineLegacyTest, convertCharsetUnsupportedChars) {
+    auto result = qjsvalue_cast<QByteArray>(
+            evaluate("engine.convertCharset('ISO-8859-15', 'مايأ نامز')"));
+    char sub = '\x1A'; // ASCII/Latin9 SUB character
+    EXPECT_EQ(result,
+            QByteArrayView::fromArray(
+                    {sub, sub, sub, sub, '\x20', sub, sub, sub, sub}));
+}
+
+#define COMPLICATEDSTRINGLITERAL "Hello, 世界! שלום! こんにちは! 안녕하세요! 😊"
+
+static int convertedCharsetForString(ControllerScriptInterfaceLegacy::WellKnownCharsets charset) {
+    // the expected length after conversion of COMPLICATEDSTRINGLITERAL
+    using enum ControllerScriptInterfaceLegacy::WellKnownCharsets;
+    switch (charset) {
+    case US_ASCII:
+    case Latin9:
+    case ISO_8859_15:
+        return 32;
+    case Latin1:
+    case ISO_8859_1:
+        return 33;
+    case UTF_8:
+        return 63;
+    case UTF_16BE:
+    case UTF_16LE:
+        return 66;
+    case UCS2:
+    case ISO_10646_UCS_2:
+        return 68;
+    }
+    // unreachable (TODO assert false?)
+    return 0;
+}
+
+TEST_F(ControllerScriptEngineLegacyTest, convertCharsetAllWellKnownCharsets) {
+    QMetaEnum charsetEnumEntry = QMetaEnum::fromType<
+            ControllerScriptInterfaceLegacy::WellKnownCharsets>();
+
+    for (int i = 0; i < charsetEnumEntry.keyCount(); ++i) {
+        QString key = charsetEnumEntry.key(i);
+        auto enumValue =
+                static_cast<ControllerScriptInterfaceLegacy::WellKnownCharsets>(
+                        charsetEnumEntry.value(i));
+        QString source = QStringLiteral(
+                "engine.convertCharset(engine.WellKnownCharsets.%1, "
+                "'" COMPLICATEDSTRINGLITERAL "')")
+                                 .arg(key);
+        auto result = qjsvalue_cast<QByteArray>(evaluate(source));
+        EXPECT_EQ(result.size(), convertedCharsetForString(enumValue))
+                << "Unexpected length of converted string for encoding: '"
+                << key.toStdString() << "'";
+    }
+}
+
 #ifdef MIXXX_USE_QML
 class MockScreenRender : public ControllerRenderingEngine {
   public: