Merge branch 'master' of ssh://codereview.qt-project.org:29418/playground/v4vm into v4

This is the initial merge of the v4vm JS engine, designed specifically for QML.

The engine is tested on Linux and Mac OS X, works on x86, x86-64 and ARM.

Change-Id: I826b72cfa3d3575007b70d78604080582db568db

Reviewed-by: Lars Knoll <lars.knoll@digia.com>

1 files changed, 731 insertions, 0 deletions

diff --git a/src/qml/qml/v4vm/qv4globalobject.cpp b/src/qml/qml/v4vm/qv4globalobject.cpp
new file mode 100644
index 0000000000..75da51a9b6
--- /dev/null
+++ b/src/qml/qml/v4vm/qv4globalobject.cpp
@@ -0,0 +1,731 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the V4VM module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qv4globalobject.h"
+#include "qv4mm.h"
+#include "qv4value.h"
+#include "qv4context.h"
+
+#include <private/qqmljsengine_p.h>
+#include <private/qqmljslexer_p.h>
+#include <private/qqmljsparser_p.h>
+#include <private/qqmljsast_p.h>
+#include <qv4jsir_p.h>
+#include <qv4codegen_p.h>
+#include "private/qlocale_tools_p.h"
+
+#include <QtCore/QDebug>
+#include <QtCore/QString>
+#include <iostream>
+#include "qv4alloca_p.h"
+
+#include <wtf/MathExtras.h>
+
+using namespace QQmlJS::VM;
+
+static inline char toHex(char c)
+{
+    static const char hexnumbers[] = "0123456789ABCDEF";
+    return hexnumbers[c & 0xf];
+}
+
+static int fromHex(QChar ch)
+{
+    ushort c = ch.unicode();
+    if ((c >= '0') && (c <= '9'))
+        return c - '0';
+    if ((c >= 'A') && (c <= 'F'))
+        return c - 'A' + 10;
+    if ((c >= 'a') && (c <= 'f'))
+        return c - 'a' + 10;
+    return -1;
+}
+
+static QString escape(const QString &input)
+{
+    QString output;
+    output.reserve(input.size() * 3);
+    const int length = input.length();
+    for (int i = 0; i < length; ++i) {
+        ushort uc = input.at(i).unicode();
+        if (uc < 0x100) {
+            if (   (uc > 0x60 && uc < 0x7B)
+                || (uc > 0x3F && uc < 0x5B)
+                || (uc > 0x2C && uc < 0x3A)
+                || (uc == 0x2A)
+                || (uc == 0x2B)
+                || (uc == 0x5F)) {
+                output.append(QChar(uc));
+            } else {
+                output.append('%');
+                output.append(QChar(toHex(uc >> 4)));
+                output.append(QChar(toHex(uc)));
+            }
+        } else {
+            output.append('%');
+            output.append('u');
+            output.append(QChar(toHex(uc >> 12)));
+            output.append(QChar(toHex(uc >> 8)));
+            output.append(QChar(toHex(uc >> 4)));
+            output.append(QChar(toHex(uc)));
+        }
+    }
+    return output;
+}
+
+static QString unescape(const QString &input)
+{
+    QString result;
+    result.reserve(input.length());
+    int i = 0;
+    const int length = input.length();
+    while (i < length) {
+        QChar c = input.at(i++);
+        if ((c == '%') && (i + 1 < length)) {
+            QChar a = input.at(i);
+            if ((a == 'u') && (i + 4 < length)) {
+                int d3 = fromHex(input.at(i+1));
+                int d2 = fromHex(input.at(i+2));
+                int d1 = fromHex(input.at(i+3));
+                int d0 = fromHex(input.at(i+4));
+                if ((d3 != -1) && (d2 != -1) && (d1 != -1) && (d0 != -1)) {
+                    ushort uc = ushort((d3 << 12) | (d2 << 8) | (d1 << 4) | d0);
+                    result.append(QChar(uc));
+                    i += 5;
+                } else {
+                    result.append(c);
+                }
+            } else {
+                int d1 = fromHex(a);
+                int d0 = fromHex(input.at(i+1));
+                if ((d1 != -1) && (d0 != -1)) {
+                    c = (d1 << 4) | d0;
+                    i += 2;
+                }
+                result.append(c);
+            }
+        } else {
+            result.append(c);
+        }
+    }
+    return result;
+}
+
+static const char uriReserved[] = ";/?:@&=+$,#";
+static const char uriUnescaped[] = "-_.!~*'()";
+static const char uriUnescapedReserved[] = "-_.!~*'();/?:@&=+$,#";
+
+static void addEscapeSequence(QString &output, uchar ch)
+{
+    output.append(QLatin1Char('%'));
+    output.append(QLatin1Char(toHex(ch >> 4)));
+    output.append(QLatin1Char(toHex(ch & 0xf)));
+}
+
+static QString encode(const QString &input, const char *unescapedSet, bool *ok)
+{
+    *ok = true;
+    QString output;
+    const int length = input.length();
+    int i = 0;
+    while (i < length) {
+        const QChar c = input.at(i);
+        bool escape = true;
+        if ((c.unicode() >= 'a' && c.unicode() <= 'z') ||
+            (c.unicode() >= 'A' && c.unicode() <= 'Z') ||
+            (c.unicode() >= '0' && c.unicode() <= '9')) {
+            escape = false;
+        } else {
+            const char *r = unescapedSet;
+            while (*r) {
+                if (*r == c.unicode()) {
+                    escape = false;
+                    break;
+                }
+                ++r;
+            }
+        }
+        if (escape) {
+            uint uc = c.unicode();
+            if ((uc >= 0xDC00) && (uc <= 0xDFFF)) {
+                *ok = false;
+                break;
+            }
+            if (!((uc < 0xD800) || (uc > 0xDBFF))) {
+                ++i;
+                if (i == length) {
+                    *ok = false;
+                    break;
+                }
+                const uint uc2 = input.at(i).unicode();
+                if ((uc2 < 0xDC00) || (uc2 > 0xDFFF)) {
+                    *ok = false;
+                    break;
+                }
+                uc = ((uc - 0xD800) * 0x400) + (uc2 - 0xDC00) + 0x10000;
+            }
+            if (uc < 0x80) {
+                addEscapeSequence(output, (uchar)uc);
+            } else {
+                if (uc < 0x0800) {
+                    addEscapeSequence(output, 0xc0 | ((uchar) (uc >> 6)));
+                } else {
+
+                    if (QChar::requiresSurrogates(uc)) {
+                        addEscapeSequence(output, 0xf0 | ((uchar) (uc >> 18)));
+                        addEscapeSequence(output, 0x80 | (((uchar) (uc >> 12)) & 0x3f));
+                    } else {
+                        addEscapeSequence(output, 0xe0 | (((uchar) (uc >> 12)) & 0x3f));
+                    }
+                    addEscapeSequence(output, 0x80 | (((uchar) (uc >> 6)) & 0x3f));
+                }
+                addEscapeSequence(output, 0x80 | ((uchar) (uc&0x3f)));
+            }
+        } else {
+            output.append(c);
+        }
+        ++i;
+    }
+    if (i != length)
+        *ok = false;
+    return output;
+}
+
+enum DecodeMode {
+    DecodeAll,
+    DecodeNonReserved
+};
+
+static QString decode(const QString &input, DecodeMode decodeMode, bool *ok)
+{
+    *ok = true;
+    QString output;
+    output.reserve(input.length());
+    const int length = input.length();
+    int i = 0;
+    const QChar percent = QLatin1Char('%');
+    while (i < length) {
+        const QChar ch = input.at(i);
+        if (ch == percent) {
+            int start = i;
+            if (i + 2 >= length)
+                goto error;
+
+            int d1 = fromHex(input.at(i+1));
+            int d0 = fromHex(input.at(i+2));
+            if ((d1 == -1) || (d0 == -1))
+                goto error;
+
+            int b = (d1 << 4) | d0;
+            i += 2;
+            if (b & 0x80) {
+                int uc;
+                int min_uc;
+                int need;
+                if ((b & 0xe0) == 0xc0) {
+                    uc = b & 0x1f;
+                    need = 1;
+                    min_uc = 0x80;
+                } else if ((b & 0xf0) == 0xe0) {
+                    uc = b & 0x0f;
+                    need = 2;
+                    min_uc = 0x800;
+                } else if ((b & 0xf8) == 0xf0) {
+                    uc = b & 0x07;
+                    need = 3;
+                    min_uc = 0x10000;
+                } else {
+                    goto error;
+                }
+
+                if (i + (3 * need) >= length)
+                    goto error;
+
+                for (int j = 0; j < need; ++j) {
+                    ++i;
+                    if (input.at(i) != percent)
+                        goto error;
+
+                    d1 = fromHex(input.at(i+1));
+                    d0 = fromHex(input.at(i+2));
+                    if ((d1 == -1) || (d0 == -1))
+                        goto error;
+
+                    b = (d1 << 4) | d0;
+                    if ((b & 0xC0) != 0x80)
+                        goto error;
+
+                    i += 2;
+                    uc = (uc << 6) + (b & 0x3f);
+                }
+                if (uc < min_uc)
+                    goto error;
+
+                if (uc < 0x10000) {
+                    output.append(QChar(uc));
+                } else {
+                    if (uc > 0x10FFFF)
+                        goto error;
+
+                    ushort l = ushort(((uc - 0x10000) & 0x3FF) + 0xDC00);
+                    ushort h = ushort((((uc - 0x10000) >> 10) & 0x3FF) + 0xD800);
+                    output.append(QChar(h));
+                    output.append(QChar(l));
+                }
+            } else {
+                if (decodeMode == DecodeNonReserved && b <= 0x40) {
+                    const char *r = uriReserved;
+                    while (*r) {
+                        if (*r == b)
+                            break;
+                        ++r;
+                    }
+                    if (*r)
+                        output.append(input.mid(start, i - start + 1));
+                    else
+                        output.append(QChar(b));
+                } else {
+                    output.append(QChar(b));
+                }
+            }
+        } else {
+            output.append(ch);
+        }
+        ++i;
+    }
+    if (i != length)
+        *ok = false;
+    return output;
+  error:
+    *ok = false;
+    return QString();
+}
+
+DEFINE_MANAGED_VTABLE(EvalFunction);
+
+EvalFunction::EvalFunction(ExecutionContext *scope)
+    : FunctionObject(scope)
+    , qmlActivation(0)
+{
+    vtbl = &static_vtbl;
+    name = scope->engine->id_eval;
+    defineReadonlyProperty(scope->engine->id_length, Value::fromInt32(1));
+}
+
+EvalFunction::EvalFunction(ExecutionContext *scope, Object *qmlActivation)
+    : FunctionObject(scope)
+{
+    vtbl = &static_vtbl;
+    name = scope->engine->id_eval;
+    defineReadonlyProperty(scope->engine->id_length, Value::fromInt32(1));
+    this->qmlActivation = qmlActivation;
+}
+
+Value EvalFunction::evalCall(ExecutionContext *parentContext, Value /*thisObject*/, Value *args, int argc, bool directCall)
+{
+    if (argc < 1)
+        return Value::undefinedValue();
+
+    ExecutionEngine *engine = parentContext->engine;
+    ExecutionContext *ctx = parentContext;
+
+    if (!directCall) {
+        // the context for eval should be the global scope, so we fake a root
+        // context
+        ctx = engine->pushGlobalContext();
+    }
+
+    if (!args[0].isString())
+        return args[0];
+
+    const QString code = args[0].stringValue()->toQString();
+    bool inheritContext = !ctx->strictMode;
+
+    QQmlJS::VM::Function *f = parseSource(ctx, QStringLiteral("eval code"),
+                                          code, QQmlJS::Codegen::EvalCode,
+                                          (directCall && parentContext->strictMode), inheritContext);
+
+    if (!f)
+        return Value::undefinedValue();
+
+    strictMode = f->isStrict || (ctx->strictMode);
+    if (qmlActivation)
+        strictMode = true;
+
+    usesArgumentsObject = f->usesArgumentsObject;
+    needsActivation = f->needsActivation();
+
+    if (strictMode) {
+        CallContext *k = ctx->engine->newCallContext(this, ctx->thisObject, 0, 0);
+        if (qmlActivation) {
+            k->activation = qmlActivation;
+            k->type = ExecutionContext::Type_QmlContext;
+        }
+        ctx = k;
+    }
+
+    // set the correct strict mode flag on the context
+    bool cstrict = ctx->strictMode;
+    ctx->strictMode = strictMode;
+
+    Value result = Value::undefinedValue();
+    try {
+        result = f->code(ctx, f->codeData);
+    } catch (Exception &ex) {
+        ctx->strictMode = cstrict;
+        if (strictMode)
+            ex.partiallyUnwindContext(parentContext);
+        throw;
+    }
+
+    ctx->strictMode = cstrict;
+
+    while (engine->current != parentContext)
+        engine->popContext();
+
+    return result;
+}
+
+
+Value EvalFunction::call(Managed *that, ExecutionContext *context, const Value &thisObject, Value *args, int argc)
+{
+    // indirect call
+    return static_cast<EvalFunction *>(that)->evalCall(context, thisObject, args, argc, false);
+}
+
+//Value EvalFunction::construct(ExecutionContext *ctx, Value *, int)
+//{
+//    ctx->throwTypeError();
+//    return Value::undefinedValue();
+//}
+
+QQmlJS::VM::Function *EvalFunction::parseSource(QQmlJS::VM::ExecutionContext *ctx,
+                                                const QString &fileName, const QString &source,
+                                                QQmlJS::Codegen::Mode mode,
+                                                bool strictMode, bool inheritContext)
+{
+    using namespace QQmlJS;
+
+    MemoryManager::GCBlocker gcBlocker(ctx->engine->memoryManager);
+
+    VM::ExecutionEngine *vm = ctx->engine;
+    V4IR::Module module;
+    VM::Function *globalCode = 0;
+
+    {
+        QQmlJS::Engine ee, *engine = &ee;
+        Lexer lexer(engine);
+        lexer.setCode(source, 1, false);
+        Parser parser(engine);
+
+        const bool parsed = parser.parseProgram();
+
+        VM::DiagnosticMessage *error = 0, **errIt = &error;
+        foreach (const QQmlJS::DiagnosticMessage &m, parser.diagnosticMessages()) {
+            if (m.isError()) {
+                *errIt = new VM::DiagnosticMessage;
+                (*errIt)->fileName = fileName;
+                (*errIt)->offset = m.loc.offset;
+                (*errIt)->length = m.loc.length;
+                (*errIt)->startLine = m.loc.startLine;
+                (*errIt)->startColumn = m.loc.startColumn;
+                (*errIt)->type = VM::DiagnosticMessage::Error;
+                (*errIt)->message = m.message;
+                errIt = &(*errIt)->next;
+            } else {
+                std::cerr << qPrintable(fileName) << ':' << m.loc.startLine << ':' << m.loc.startColumn
+                          << ": warning: " << qPrintable(m.message) << std::endl;
+            }
+        }
+        if (error)
+            ctx->throwSyntaxError(error);
+
+        if (parsed) {
+            using namespace AST;
+            Program *program = AST::cast<Program *>(parser.rootNode());
+            if (!program) {
+                // if parsing was successful, and we have no program, then
+                // we're done...:
+                return 0;
+            }
+
+            QStringList inheritedLocals;
+            if (inheritContext)
+                for (String * const *i = ctx->variables(), * const *ei = i + ctx->variableCount(); i < ei; ++i)
+                    inheritedLocals.append(*i ? (*i)->toQString() : QString());
+
+            Codegen cg(ctx, strictMode);
+            V4IR::Function *globalIRCode = cg(fileName, source, program, &module, mode, inheritedLocals);
+            QScopedPointer<EvalInstructionSelection> isel(ctx->engine->iselFactory->create(vm, &module));
+            if (inheritContext)
+                isel->setUseFastLookups(false);
+            if (globalIRCode)
+                globalCode = isel->vmFunction(globalIRCode);
+        }
+
+        if (! globalCode)
+            // ### should be a syntax error
+            ctx->throwTypeError();
+    }
+
+    return globalCode;
+}
+
+static inline int toInt(const QChar &qc, int R)
+{
+    ushort c = qc.unicode();
+    int v = -1;
+    if (c >= '0' && c <= '9')
+        v = c - '0';
+    else if (c >= 'A' && c <= 'Z')
+        v = c - 'A' + 10;
+    else if (c >= 'a' && c <= 'z')
+        v = c - 'a' + 10;
+    if (v >= 0 && v < R)
+        return v;
+    else
+        return -1;
+}
+
+// parseInt [15.1.2.2]
+Value GlobalFunctions::method_parseInt(SimpleCallContext *context)
+{
+    Value string = context->argument(0);
+    Value radix = context->argument(1);
+    int R = radix.isUndefined() ? 0 : radix.toInt32();
+
+    // [15.1.2.2] step by step:
+    String *inputString = string.toString(context); // 1
+    QString trimmed = inputString->toQString().trimmed(); // 2
+    const QChar *pos = trimmed.constData();
+    const QChar *end = pos + trimmed.length();
+
+    int sign = 1; // 3
+    if (pos != end) {
+        if (*pos == QLatin1Char('-'))
+            sign = -1; // 4
+        if (*pos == QLatin1Char('-') || *pos == QLatin1Char('+'))
+            ++pos; // 5
+    }
+    bool stripPrefix = true; // 7
+    if (R) { // 8
+        if (R < 2 || R > 36)
+            return Value::fromDouble(std::numeric_limits<double>::quiet_NaN()); // 8a
+        if (R != 16)
+            stripPrefix = false; // 8b
+    } else { // 9
+        R = 10; // 9a
+    }
+    if (stripPrefix) { // 10
+        if ((end - pos >= 2)
+                && (pos[0] == QLatin1Char('0'))
+                && (pos[1] == QLatin1Char('x') || pos[1] == QLatin1Char('X'))) { // 10a
+            pos += 2;
+            R = 16;
+        }
+    }
+    // 11: Z is progressively built below
+    // 13: this is handled by the toInt function
+    if (pos == end) // 12
+        return Value::fromDouble(std::numeric_limits<double>::quiet_NaN());
+    bool overflow = false;
+    qint64 v_overflow;
+    unsigned overflow_digit_count = 0;
+    int d = toInt(*pos++, R);
+    if (d == -1)
+        return Value::fromDouble(std::numeric_limits<double>::quiet_NaN());
+    qint64 v = d;
+    while (pos != end) {
+        d = toInt(*pos++, R);
+        if (d == -1)
+            break;
+        if (overflow) {
+            if (overflow_digit_count == 0) {
+                v_overflow = v;
+                v = 0;
+            }
+            ++overflow_digit_count;
+            v = v * R + d;
+        } else {
+            qint64 vNew = v * R + d;
+            if (vNew < v) {
+                overflow = true;
+                --pos;
+            } else {
+                v = vNew;
+            }
+        }
+    }
+
+    if (overflow) {
+        double result = (double) v_overflow * pow(R, overflow_digit_count);
+        result += v;
+        return Value::fromDouble(sign * result);
+    } else {
+        return Value::fromDouble(sign * (double) v); // 15
+    }
+}
+
+// parseFloat [15.1.2.3]
+Value GlobalFunctions::method_parseFloat(SimpleCallContext *context)
+{
+    Value string = context->argument(0);
+
+    // [15.1.2.3] step by step:
+    String *inputString = string.toString(context); // 1
+    QString trimmed = inputString->toQString().trimmed(); // 2
+
+    // 4:
+    if (trimmed.startsWith(QLatin1String("Infinity"))
+            || trimmed.startsWith(QLatin1String("+Infinity")))
+        return Value::fromDouble(Q_INFINITY);
+    if (trimmed.startsWith("-Infinity"))
+        return Value::fromDouble(-Q_INFINITY);
+    QByteArray ba = trimmed.toLatin1();
+    bool ok;
+    const char *begin = ba.constData();
+    const char *end = 0;
+    double d = qstrtod(begin, &end, &ok);
+    if (end - begin == 0)
+        return Value::fromDouble(std::numeric_limits<double>::quiet_NaN()); // 3
+    else
+        return Value::fromDouble(d);
+}
+
+/// isNaN [15.1.2.4]
+Value GlobalFunctions::method_isNaN(SimpleCallContext *context)
+{
+    const Value &v = context->argument(0);
+    if (v.integerCompatible())
+        return Value::fromBoolean(false);
+
+    double d = v.toNumber();
+    return Value::fromBoolean(isnan(d));
+}
+
+/// isFinite [15.1.2.5]
+Value GlobalFunctions::method_isFinite(SimpleCallContext *context)
+{
+    const Value &v = context->argument(0);
+    if (v.integerCompatible())
+        return Value::fromBoolean(true);
+
+    double d = v.toNumber();
+    return Value::fromBoolean(std::isfinite(d));
+}
+
+/// decodeURI [15.1.3.1]
+Value GlobalFunctions::method_decodeURI(SimpleCallContext *context)
+{
+    if (context->argumentCount == 0)
+        return Value::undefinedValue();
+
+    QString uriString = context->arguments[0].toString(context)->toQString();
+    bool ok;
+    QString out = decode(uriString, DecodeNonReserved, &ok);
+    if (!ok)
+        context->throwURIError(Value::fromString(context, QStringLiteral("malformed URI sequence")));
+
+    return Value::fromString(context, out);
+}
+
+/// decodeURIComponent [15.1.3.2]
+Value GlobalFunctions::method_decodeURIComponent(SimpleCallContext *context)
+{
+    if (context->argumentCount == 0)
+        return Value::undefinedValue();
+
+    QString uriString = context->arguments[0].toString(context)->toQString();
+    bool ok;
+    QString out = decode(uriString, DecodeAll, &ok);
+    if (!ok)
+        context->throwURIError(Value::fromString(context, QStringLiteral("malformed URI sequence")));
+
+    return Value::fromString(context, out);
+}
+
+/// encodeURI [15.1.3.3]
+Value GlobalFunctions::method_encodeURI(SimpleCallContext *context)
+{
+    if (context->argumentCount == 0)
+        return Value::undefinedValue();
+
+    QString uriString = context->arguments[0].toString(context)->toQString();
+    bool ok;
+    QString out = encode(uriString, uriUnescapedReserved, &ok);
+    if (!ok)
+        context->throwURIError(Value::fromString(context, QStringLiteral("malformed URI sequence")));
+
+    return Value::fromString(context, out);
+}
+
+/// encodeURIComponent [15.1.3.4]
+Value GlobalFunctions::method_encodeURIComponent(SimpleCallContext *context)
+{
+    if (context->argumentCount == 0)
+        return Value::undefinedValue();
+
+    QString uriString = context->arguments[0].toString(context)->toQString();
+    bool ok;
+    QString out = encode(uriString, uriUnescaped, &ok);
+    if (!ok)
+        context->throwURIError(Value::fromString(context, QStringLiteral("malformed URI sequence")));
+
+    return Value::fromString(context, out);
+}
+
+Value GlobalFunctions::method_escape(SimpleCallContext *context)
+{
+    if (!context->argumentCount)
+        return Value::fromString(context, QStringLiteral("undefined"));
+
+    QString str = context->argument(0).toString(context)->toQString();
+    return Value::fromString(context, escape(str));
+}
+
+Value GlobalFunctions::method_unescape(SimpleCallContext *context)
+{
+    if (!context->argumentCount)
+        return Value::fromString(context, QStringLiteral("undefined"));
+
+    QString str = context->argument(0).toString(context)->toQString();
+    return Value::fromString(context, unescape(str));
+}