Simplify JS bindings generation

Added a little helper script that can generate the code to
set up the prototype properties

Change-Id: I957ed4419c8b16398720fea4203c1a00434c4fba
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

7 files changed, 279 insertions, 99 deletions

diff --git a/.gitignore b/.gitignore
index fa221a5ede..c5cbc02951 100644
--- a/.gitignore
+++ b/.gitignore
@@ -274,3 +274,5 @@ src/qml/RegExpJitTables.h
 src/qml/udis86_itab.c
 src/qml/udis86_itab.h
 
+# Generated V4 JS bindings
+*_jsclass.cpp
diff --git a/src/qml/qml/v4/qv4dateobject.cpp b/src/qml/qml/v4/qv4dateobject.cpp
index 6d78e479e3..c67d686a1d 100644
--- a/src/qml/qml/v4/qv4dateobject.cpp
+++ b/src/qml/qml/v4/qv4dateobject.cpp
@@ -651,15 +651,7 @@ QDateTime DateObject::toQDateTime() const
     return ToDateTime(value.asDouble(), Qt::LocalTime);
 }
 
-DEFINE_MANAGED_VTABLE(DateCtor);
-
-DateCtor::DateCtor(ExecutionContext *scope)
-    : FunctionObject(scope, scope->engine->newIdentifier(QStringLiteral("Date")))
-{
-    vtbl = &static_vtbl;
-}
-
-Value DateCtor::construct(Managed *, ExecutionContext *ctx, Value *args, int argc)
+Value DatePrototype::ctor_method_construct(Managed *, ExecutionContext *ctx, Value *args, int argc)
 {
     double t = 0;
 
@@ -697,7 +689,7 @@ Value DateCtor::construct(Managed *, ExecutionContext *ctx, Value *args, int arg
     return Value::fromObject(d);
 }
 
-Value DateCtor::call(Managed *, ExecutionContext *ctx, const Value &, Value *, int)
+Value DatePrototype::ctor_method_call(Managed *, ExecutionContext *ctx, const Value &, Value *, int)
 {
     double t = currentTime();
     return Value::fromString(ctx, ToString(t));
@@ -705,61 +697,9 @@ Value DateCtor::call(Managed *, ExecutionContext *ctx, const Value &, Value *, i
 
 void DatePrototype::init(ExecutionContext *ctx, const Value &ctor)
 {
-    ctor.objectValue()->defineReadonlyProperty(ctx->engine->id_prototype, Value::fromObject(this));
-    ctor.objectValue()->defineReadonlyProperty(ctx->engine->id_length, Value::fromInt32(7));
     LocalTZA = getLocalTZA();
 
-    ctor.objectValue()->defineDefaultProperty(ctx, QStringLiteral("parse"), method_parse, 1);
-    ctor.objectValue()->defineDefaultProperty(ctx, QStringLiteral("UTC"), method_UTC, 7);
-    ctor.objectValue()->defineDefaultProperty(ctx, QStringLiteral("now"), method_now, 0);
-
-    defineDefaultProperty(ctx, QStringLiteral("constructor"), ctor);
-    defineDefaultProperty(ctx, QStringLiteral("toString"), method_toString, 0);
-    defineDefaultProperty(ctx, QStringLiteral("toDateString"), method_toDateString, 0);
-    defineDefaultProperty(ctx, QStringLiteral("toTimeString"), method_toTimeString, 0);
-    defineDefaultProperty(ctx, QStringLiteral("toLocaleString"), method_toLocaleString, 0);
-    defineDefaultProperty(ctx, QStringLiteral("toLocaleDateString"), method_toLocaleDateString, 0);
-    defineDefaultProperty(ctx, QStringLiteral("toLocaleTimeString"), method_toLocaleTimeString, 0);
-    defineDefaultProperty(ctx, QStringLiteral("valueOf"), method_valueOf, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getTime"), method_getTime, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getYear"), method_getYear, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getFullYear"), method_getFullYear, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getUTCFullYear"), method_getUTCFullYear, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getMonth"), method_getMonth, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getUTCMonth"), method_getUTCMonth, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getDate"), method_getDate, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getUTCDate"), method_getUTCDate, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getDay"), method_getDay, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getUTCDay"), method_getUTCDay, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getHours"), method_getHours, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getUTCHours"), method_getUTCHours, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getMinutes"), method_getMinutes, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getUTCMinutes"), method_getUTCMinutes, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getSeconds"), method_getSeconds, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getUTCSeconds"), method_getUTCSeconds, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getMilliseconds"), method_getMilliseconds, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getUTCMilliseconds"), method_getUTCMilliseconds, 0);
-    defineDefaultProperty(ctx, QStringLiteral("getTimezoneOffset"), method_getTimezoneOffset, 0);
-    defineDefaultProperty(ctx, QStringLiteral("setTime"), method_setTime, 1);
-    defineDefaultProperty(ctx, QStringLiteral("setMilliseconds"), method_setMilliseconds, 1);
-    defineDefaultProperty(ctx, QStringLiteral("setUTCMilliseconds"), method_setUTCMilliseconds, 1);
-    defineDefaultProperty(ctx, QStringLiteral("setSeconds"), method_setSeconds, 2);
-    defineDefaultProperty(ctx, QStringLiteral("setUTCSeconds"), method_setUTCSeconds, 2);
-    defineDefaultProperty(ctx, QStringLiteral("setMinutes"), method_setMinutes, 3);
-    defineDefaultProperty(ctx, QStringLiteral("setUTCMinutes"), method_setUTCMinutes, 3);
-    defineDefaultProperty(ctx, QStringLiteral("setHours"), method_setHours, 4);
-    defineDefaultProperty(ctx, QStringLiteral("setUTCHours"), method_setUTCHours, 4);
-    defineDefaultProperty(ctx, QStringLiteral("setDate"), method_setDate, 1);
-    defineDefaultProperty(ctx, QStringLiteral("setUTCDate"), method_setUTCDate, 1);
-    defineDefaultProperty(ctx, QStringLiteral("setMonth"), method_setMonth, 2);
-    defineDefaultProperty(ctx, QStringLiteral("setUTCMonth"), method_setUTCMonth, 2);
-    defineDefaultProperty(ctx, QStringLiteral("setYear"), method_setYear, 1);
-    defineDefaultProperty(ctx, QStringLiteral("setFullYear"), method_setFullYear, 3);
-    defineDefaultProperty(ctx, QStringLiteral("setUTCFullYear"), method_setUTCFullYear, 3);
-    defineDefaultProperty(ctx, QStringLiteral("toUTCString"), method_toUTCString, 0);
-    defineDefaultProperty(ctx, QStringLiteral("toGMTString"), method_toUTCString, 0);
-    defineDefaultProperty(ctx, QStringLiteral("toISOString"), method_toISOString, 0);
-    defineDefaultProperty(ctx, QStringLiteral("toJSON"), method_toJSON, 1);
+    initClass(ctx->engine, ctor);
 }
 
 double DatePrototype::getThisDate(ExecutionContext *ctx)
@@ -772,12 +712,12 @@ double DatePrototype::getThisDate(ExecutionContext *ctx)
     }
 }
 
-Value DatePrototype::method_parse(SimpleCallContext *ctx)
+Value DatePrototype::ctor_method_parse(SimpleCallContext *ctx)
 {
     return Value::fromDouble(ParseString(ctx->argument(0).toString(ctx)->toQString()));
 }
 
-Value DatePrototype::method_UTC(SimpleCallContext *ctx)
+Value DatePrototype::ctor_method_UTC(SimpleCallContext *ctx)
 {
     const int numArgs = ctx->argumentCount;
     if (numArgs >= 2) {
@@ -797,7 +737,7 @@ Value DatePrototype::method_UTC(SimpleCallContext *ctx)
     return Value::undefinedValue();
 }
 
-Value DatePrototype::method_now(SimpleCallContext *ctx)
+Value DatePrototype::ctor_method_now(SimpleCallContext *ctx)
 {
     Q_UNUSED(ctx);
     double t = currentTime();
@@ -1308,3 +1248,5 @@ Value DatePrototype::method_toJSON(SimpleCallContext *ctx)
 
     return toIso->call(ctx, ctx->thisObject, 0, 0);
 }
+
+#include "qv4dateobject_p_jsclass.cpp"
diff --git a/src/qml/qml/v4/qv4dateobject_p.h b/src/qml/qml/v4/qv4dateobject_p.h
index 629dfa57e7..ecb7384d99 100644
--- a/src/qml/qml/v4/qv4dateobject_p.h
+++ b/src/qml/qml/v4/qv4dateobject_p.h
@@ -59,27 +59,23 @@ struct DateObject: Object {
     QDateTime toQDateTime() const;
 };
 
-struct DateCtor: FunctionObject
+struct QV4_JS_CLASS(DatePrototype): DateObject
 {
-    DateCtor(ExecutionContext *scope);
+    QV4_ANNOTATE(argc 7)
 
-    static Value construct(Managed *, ExecutionContext *context, Value *args, int argc);
-    static Value call(Managed *that, ExecutionContext *, const Value &, Value *, int);
-
-protected:
-    static const ManagedVTable static_vtbl;
-};
-
-struct DatePrototype: DateObject
-{
     DatePrototype(ExecutionEngine *engine): DateObject(engine, Value::fromDouble(qSNaN())) {}
     void init(ExecutionContext *ctx, const Value &ctor);
+    void initClass(ExecutionEngine *ctx, const Value &ctor);
+    static Object *newConstructor(ExecutionContext *scope);
 
     static double getThisDate(ExecutionContext *ctx);
 
-    static Value method_parse(SimpleCallContext *ctx);
-    static Value method_UTC(SimpleCallContext *ctx);
-    static Value method_now(SimpleCallContext *ctx);
+    static Value ctor_method_construct(Managed *, ExecutionContext *context, Value *args, int argc);
+    static Value ctor_method_call(Managed *that, ExecutionContext *, const Value &, Value *, int);
+
+    static Value ctor_method_parse(SimpleCallContext *ctx) QV4_ARGC(1);
+    static Value ctor_method_UTC(SimpleCallContext *ctx) QV4_ARGC(7);
+    static Value ctor_method_now(SimpleCallContext *ctx);
 
     static Value method_toString(SimpleCallContext *ctx);
     static Value method_toDateString(SimpleCallContext *ctx);
@@ -107,25 +103,25 @@ struct DatePrototype: DateObject
     static Value method_getMilliseconds(SimpleCallContext *ctx);
     static Value method_getUTCMilliseconds(SimpleCallContext *ctx);
     static Value method_getTimezoneOffset(SimpleCallContext *ctx);
-    static Value method_setTime(SimpleCallContext *ctx);
-    static Value method_setMilliseconds(SimpleCallContext *ctx);
-    static Value method_setUTCMilliseconds(SimpleCallContext *ctx);
-    static Value method_setSeconds(SimpleCallContext *ctx);
-    static Value method_setUTCSeconds(SimpleCallContext *ctx);
-    static Value method_setMinutes(SimpleCallContext *ctx);
-    static Value method_setUTCMinutes(SimpleCallContext *ctx);
-    static Value method_setHours(SimpleCallContext *ctx);
-    static Value method_setUTCHours(SimpleCallContext *ctx);
-    static Value method_setDate(SimpleCallContext *ctx);
-    static Value method_setUTCDate(SimpleCallContext *ctx);
-    static Value method_setMonth(SimpleCallContext *ctx);
-    static Value method_setUTCMonth(SimpleCallContext *ctx);
-    static Value method_setYear(SimpleCallContext *ctx);
-    static Value method_setFullYear(SimpleCallContext *ctx);
-    static Value method_setUTCFullYear(SimpleCallContext *ctx);
-    static Value method_toUTCString(SimpleCallContext *ctx);
+    static Value method_setTime(SimpleCallContext *ctx) QV4_ARGC(1);
+    static Value method_setMilliseconds(SimpleCallContext *ctx) QV4_ARGC(1);
+    static Value method_setUTCMilliseconds(SimpleCallContext *ctx) QV4_ARGC(1);
+    static Value method_setSeconds(SimpleCallContext *ctx) QV4_ARGC(2);
+    static Value method_setUTCSeconds(SimpleCallContext *ctx) QV4_ARGC(2);
+    static Value method_setMinutes(SimpleCallContext *ctx) QV4_ARGC(3);
+    static Value method_setUTCMinutes(SimpleCallContext *ctx) QV4_ARGC(3);
+    static Value method_setHours(SimpleCallContext *ctx) QV4_ARGC(4);
+    static Value method_setUTCHours(SimpleCallContext *ctx) QV4_ARGC(4);
+    static Value method_setDate(SimpleCallContext *ctx) QV4_ARGC(1);
+    static Value method_setUTCDate(SimpleCallContext *ctx) QV4_ARGC(1);
+    static Value method_setMonth(SimpleCallContext *ctx) QV4_ARGC(2);
+    static Value method_setUTCMonth(SimpleCallContext *ctx) QV4_ARGC(2);
+    static Value method_setYear(SimpleCallContext *ctx) QV4_ARGC(1);
+    static Value method_setFullYear(SimpleCallContext *ctx) QV4_ARGC(3);
+    static Value method_setUTCFullYear(SimpleCallContext *ctx) QV4_ARGC(3);
+    static Value method_toUTCString(SimpleCallContext *ctx) QV4_ANNOTATE(alias toGMTString);
     static Value method_toISOString(SimpleCallContext *ctx);
-    static Value method_toJSON(SimpleCallContext *ctx);
+    static Value method_toJSON(SimpleCallContext *ctx) QV4_ARGC(1);
 };
 
 }
diff --git a/src/qml/qml/v4/qv4engine.cpp b/src/qml/qml/v4/qv4engine.cpp
index a507cab13c..c2c14ef5b2 100644
--- a/src/qml/qml/v4/qv4engine.cpp
+++ b/src/qml/qml/v4/qv4engine.cpp
@@ -151,7 +151,7 @@ ExecutionEngine::ExecutionEngine(QQmlJS::EvalISelFactory *factory)
     booleanCtor = Value::fromObject(new (memoryManager) BooleanCtor(rootContext));
     arrayCtor = Value::fromObject(new (memoryManager) ArrayCtor(rootContext));
     functionCtor = Value::fromObject(new (memoryManager) FunctionCtor(rootContext));
-    dateCtor = Value::fromObject(new (memoryManager) DateCtor(rootContext));
+    dateCtor = Value::fromObject(DatePrototype::newConstructor(rootContext));
     regExpCtor = Value::fromObject(new (memoryManager) RegExpCtor(rootContext));
     errorCtor = Value::fromObject(new (memoryManager) ErrorCtor(rootContext));
     evalErrorCtor = Value::fromObject(new (memoryManager) EvalErrorCtor(rootContext));
diff --git a/src/qml/qml/v4/qv4object_p.h b/src/qml/qml/v4/qv4object_p.h
index b8d3b1c23d..ac5ca07a01 100644
--- a/src/qml/qml/v4/qv4object_p.h
+++ b/src/qml/qml/v4/qv4object_p.h
@@ -420,6 +420,11 @@ inline void Object::setArrayLengthUnchecked(uint l)
 
 }
 
+// Macros used for JS class annotation
+#define QV4_JS_CLASS(ClassName) ClassName
+#define QV4_ANNOTATE(...)
+#define QV4_ARGC(...)
+
 QT_END_NAMESPACE
 
 #endif // QMLJS_OBJECTS_H
diff --git a/src/qml/qml/v4/v4.pri b/src/qml/qml/v4/v4.pri
index 92f13ab92f..b50602b026 100644
--- a/src/qml/qml/v4/v4.pri
+++ b/src/qml/qml/v4/v4.pri
@@ -94,6 +94,16 @@ HEADERS += \
     $$PWD/qv4util_p.h \
     $$PWD/qv4executableallocator_p.h
 
+JS_CLASS_SOURCES = $$PWD/qv4dateobject_p.h
+
+js_class_bindings.output = ${QMAKE_FILE_BASE}_jsclass.cpp
+js_class_bindings.input = JS_CLASS_SOURCES
+js_class_bindings.script = $$PWD/v4classgen
+js_class_bindings.commands = python $$js_class_bindings.script ${QMAKE_FILE_IN} --output ${QMAKE_FILE_OUT}
+js_class_bindings.depends += $$js_class_bindings.script $$PWD/qv4managed_p.h
+js_class_bindings.CONFIG += no_link
+QMAKE_EXTRA_COMPILERS += js_class_bindings
+
 llvm-libs {
 
 SOURCES += \
diff --git a/src/qml/qml/v4/v4classgen b/src/qml/qml/v4/v4classgen
new file mode 100755
index 0000000000..5f046668fd
--- /dev/null
+++ b/src/qml/qml/v4/v4classgen
@@ -0,0 +1,225 @@
+#!/usr/bin/python
+
+import re, sys, os
+import argparse
+
+class ParsedMethod():
+    def __init__(self, name, methodPrefix):
+        self.name = name
+        self.methodPrefix = methodPrefix
+        self.options = {}
+
+    def generateBinding(self, out, objectPrefix = ""):
+        length = 0
+        if "argc" in self.options:
+            length = self.options["argc"]
+        out.write("    %sdefineDefaultProperty(engine, QStringLiteral(\"%s\"), %s_%s, %s);\n" % (objectPrefix, self.name, self.methodPrefix, self.name, length))
+        if "alias" in self.options:
+            out.write("    %sdefineDefaultProperty(engine, QStringLiteral(\"%s\"), %s_%s, %s);\n" % (objectPrefix, self.options["alias"], self.methodPrefix, self.name, length))
+
+class ParsedClass():
+    def __init__(self, name):
+        self.name = name
+        self.options = {}
+        self.methods = []
+        self.ctor_methods = []
+
+    def needsConstructor(self):
+        return len(self.ctor_methods) > 0
+
+def parseOptions(options):
+    options = options.split(" ")
+    result = {}
+    for opt in [options[i : i + 2] for i in range(0, len(options), 2)]:
+        result[opt[0]] = opt[1]
+    return result
+
+def parseMethod(line, match, methodPrefix):
+    annotatePattern = re.compile(r".*QV4_ANNOTATE\((?P<Options>.+)\).*")
+    argcPattern = re.compile(r".*QV4_ARGC\((?P<count>\d+)\).*")
+
+    method = ParsedMethod(match.group("MethodName"), methodPrefix)
+
+    annotateMatch = annotatePattern.match(line)
+    if annotateMatch:
+        method.options = parseOptions(annotateMatch.group("Options"))
+
+    argcMatch = argcPattern.match(line)
+    if argcMatch:
+        method.options["argc"] = argcMatch.group("count")
+
+    return method
+
+def parse(lines):
+    classes = []
+    currentClass = None
+    classPattern = re.compile(r".*QV4_JS_CLASS\((?P<ClassName>\w+)\).*")
+    annotatePattern = re.compile(r".*QV4_ANNOTATE\((?P<Options>.+)\).*")
+    methodPattern = re.compile(r".*\smethod_(?P<MethodName>\w+)\(.*\).*;")
+    ctorMethodPattern = re.compile(r".*\sctor_method_(?P<MethodName>\w+)\(.*\).*;")
+
+    for line in lines:
+        line = line.strip()
+        classMatch = classPattern.match(line)
+        if classMatch:
+            name = classMatch.group("ClassName")
+            if currentClass != None:
+                classes.append(currentClass)
+            currentClass = ParsedClass(name)
+            continue
+
+        if currentClass == None:
+            continue
+
+        methodMatch = methodPattern.match(line)
+        if methodMatch:
+            method = parseMethod(line, methodMatch, "method")
+            currentClass.methods.append(method)
+            continue
+
+        ctorMethodMatch = ctorMethodPattern.match(line)
+        if ctorMethodMatch:
+            method = parseMethod(line, ctorMethodMatch, "ctor_method")
+            currentClass.ctor_methods.append(method)
+            continue
+
+        annotateMatch = annotatePattern.match(line)
+        if annotateMatch:
+            currentClass.options = parseOptions(annotateMatch.group("Options"))
+            continue
+
+    if currentClass != None:
+        classes.append(currentClass)
+    return classes
+
+def generateBinding(out, parsedClass, vtableEntries):
+    if parsedClass.needsConstructor():
+        ctorClass = parsedClass.name.replace("Prototype", "Ctor")
+
+        out.write("class %s: public QV4::FunctionObject {\n" % ctorClass);
+        out.write("public:\n");
+        out.write("    %s(QV4::ExecutionContext *scope)\n" % ctorClass);
+        out.write("        : QV4::FunctionObject(scope, scope->engine->newIdentifier(QStringLiteral(\"%s\")))\n" % ctorClass.replace("Ctor", ""));
+        out.write("    { vtbl = &static_vtbl; }\n");
+        out.write("\n");
+        out.write("protected:\n");
+        out.write("    static const QV4::ManagedVTable static_vtbl;\n");
+        out.write("};\n\n");
+        out.write("const QV4::ManagedVTable %s::static_vtbl = {\n" % ctorClass);
+
+        ctorOverrides = set()
+        for method in parsedClass.ctor_methods:
+            ctorOverrides.add(method.name)
+
+        for method in vtableEntries:
+            entry = "FunctionObject::" + method
+            if method in ctorOverrides:
+                entry = parsedClass.name + "::ctor_method_" + method
+            out.write("    " + entry + ",\n")
+        out.write("    \"%s\"\n" % parsedClass.name.replace("Prototype", "Ctor"));
+        out.write("};\n\n")
+
+        out.write("QV4::Object *%s::newConstructor(QV4::ExecutionContext *scope)\n" % parsedClass.name)
+        out.write("{\n")
+        out.write("    return new (scope->engine->memoryManager) %s(scope);\n" % ctorClass)
+        out.write("}\n\n")
+
+    ctorSignature = ""
+    if parsedClass.needsConstructor():
+        ctorSignature = ", const Value &ctor"
+
+    out.write("void %s::initClass(QV4::ExecutionEngine *engine%s)\n" % (parsedClass.name, ctorSignature))
+    out.write("{\n")
+
+    if parsedClass.needsConstructor():
+        ctor = "ctor.objectValue()->"
+        ctorLength = 0
+        if "argc" in parsedClass.options:
+            ctorLength = parsedClass.options["argc"]
+
+        out.write("    %sdefineReadonlyProperty(engine->id_prototype, QV4::Value::fromObject(this));\n" % ctor)
+        out.write("    %sdefineReadonlyProperty(engine->id_length, QV4::Value::fromInt32(%s));\n" % (ctor, ctorLength))
+        out.write("\n")
+
+        for method in parsedClass.ctor_methods:
+            if method.name == "construct" or method.name == "call":
+                continue
+            method.generateBinding(out, ctor);
+
+        out.write("\n")
+        out.write("    defineDefaultProperty(engine, QStringLiteral(\"constructor\"), ctor);\n");
+
+        out.write("\n")
+
+    for method in parsedClass.methods:
+        method.generateBinding(out)
+
+    out.write("}\n")
+
+def extractManagedVTableLayout(basePath):
+    def VTableDefintionIterator(lines):
+        i = 0
+        while i < len(lines):
+            if lines[i].strip().startswith("#define DEFINE_MANAGED_VTABLE(classname)"):
+                break;
+            i = i + 1
+        if i >= len(lines):
+            return
+        i = i + 1
+        if not lines[i].strip().startswith("const ManagedVTable classname::static_vtbl ="):
+            print("Expected static_vtbl definition at line %s" % i)
+            return
+        i = i + 1
+        if not lines[i].strip().startswith("{"):
+            print("Expected static_vtbl definition at line %s" % i)
+            return
+        i = i + 1
+        while i < len(lines):
+            line = lines[i].strip()
+            if "#classname" in line:
+                break
+            yield line.split(",")[0]
+            i = i + 1
+        return
+
+    qv4managedHeader = basePath + "/qv4managed_p.h"
+    fields = []
+    try:
+        header = open(qv4managedHeader, "r")
+        it = VTableDefintionIterator(header.read().splitlines())
+        for entry in it:
+            fields.append(entry)
+        header.close()
+    except IOError:
+        print("Could not open qv4managed_p.h at %s" % qv4managedHeader)
+        sys.exit(1)
+    return fields
+
+parser = argparse.ArgumentParser(description="Generate V4 JS class bindings")
+parser.add_argument("input")
+parser.add_argument("--output")
+options = parser.parse_args()
+
+vtableEntries = extractManagedVTableLayout(os.path.dirname(os.path.abspath(options.input)))
+if len(vtableEntries) ==  0:
+    print("Could not parse vtable layout from qv4managed_p.h")
+    sys.exit(1)
+
+f = open(options.input)
+
+out = sys.stdout
+if options.output != None:
+    out = open(options.output, 'w')
+
+lines = f.read().splitlines()
+classes = parse(lines)
+f.close()
+
+out.write("/* Generated file, do not edit */\n")
+out.write("#include \"%s\"\n" % options.input)
+
+for parsedClass in classes:
+    out.write("\n")
+    generateBinding(out, parsedClass, vtableEntries)
+
+out.close()