Add pragma syntax to support translation context

Translator pragma can be used to set the translation context
instead of having the file name used

[ChangeLog][qml][translation][Important Behavior Changes] The context
for the translation can now be controled in a given file
using pragma Translator.

Task-number: QTBUG-114528
Change-Id: I6d9d7fb81ea969a90d8637d7277bdbe96c102088
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

8 files changed, 76 insertions, 4 deletions

diff --git a/src/qml/common/qv4compileddata_p.h b/src/qml/common/qv4compileddata_p.h
index be7dac9f34..1a97ddc5a5 100644
--- a/src/qml/common/qv4compileddata_p.h
+++ b/src/qml/common/qv4compileddata_p.h
@@ -43,7 +43,7 @@ QT_BEGIN_NAMESPACE
 // Also change the comment behind the number to describe the latest change. This has the added
 // benefit that if another patch changes the version too, it will result in a merge conflict, and
 // not get removed silently.
-#define QV4_DATA_STRUCTURE_VERSION 0x3D // Reserve special value for "no translation context"
+#define QV4_DATA_STRUCTURE_VERSION 0x3E // Add Translator pragma
 
 class QIODevice;
 class QQmlTypeNameCache;
@@ -1331,6 +1331,20 @@ struct Unit
         return reinterpret_cast<const TranslationData *>(reinterpret_cast<const char *>(this) + offsetToTranslationTable);
     }
 
+    const quint32_le *translationContextIndex() const{
+        if ( translationTableSize == 0)
+            return nullptr;
+        return reinterpret_cast<const quint32_le*>((reinterpret_cast<const char *>(this))
+                                                    + offsetToTranslationTable
+                                                    + translationTableSize * sizeof(CompiledData::TranslationData)); }
+
+    quint32_le *translationContextIndex() {
+        if ( translationTableSize == 0)
+            return nullptr;
+        return reinterpret_cast<quint32_le*>((reinterpret_cast<char *>(this))
+                                                    + offsetToTranslationTable
+                                                    + translationTableSize * sizeof(CompiledData::TranslationData)); }
+
     const ImportEntry *importEntryTable() const { return reinterpret_cast<const ImportEntry *>(reinterpret_cast<const char *>(this) + offsetToImportEntryTable); }
     const ExportEntry *localExportEntryTable() const { return reinterpret_cast<const ExportEntry *>(reinterpret_cast<const char *>(this) + offsetToLocalExportEntryTable); }
     const ExportEntry *indirectExportEntryTable() const { return reinterpret_cast<const ExportEntry *>(reinterpret_cast<const char *>(this) + offsetToIndirectExportEntryTable); }
diff --git a/src/qml/compiler/qqmlirbuilder.cpp b/src/qml/compiler/qqmlirbuilder.cpp
index 2d1a617b09..96529f0061 100644
--- a/src/qml/compiler/qqmlirbuilder.cpp
+++ b/src/qml/compiler/qqmlirbuilder.cpp
@@ -921,6 +921,10 @@ bool IRBuilder::visit(QQmlJS::AST::UiPragma *node)
         } else if (node->name == "ValueTypeBehavior"_L1) {
             if (!PragmaParser<Pragma::ValueTypeBehaviorValue>::run(this, node, pragma))
                 return false;
+        } else if (node->name == "Translator"_L1) {
+            pragma->type = Pragma::Translator;
+            pragma->translationContextIndex = registerString(node->values->value.toString());
+
         } else {
             recordError(node->pragmaToken, QCoreApplication::translate(
                             "QQmlParser", "Unknown pragma '%1'").arg(node->name));
@@ -1711,6 +1715,11 @@ void QmlUnitGenerator::generate(Document &output, const QV4::CompiledData::Depen
                     createdUnit->flags |= Unit::ValueTypesAddressable;
                 }
                 break;
+            case Pragma::Translator:
+                if (createdUnit->translationTableSize)
+                    if (quint32_le *index = createdUnit->translationContextIndex())
+                        *index = p->translationContextIndex;
+                break;
             }
         }
 
diff --git a/src/qml/compiler/qqmlirbuilder_p.h b/src/qml/compiler/qqmlirbuilder_p.h
index 8083fd752c..aad2f2fdbe 100644
--- a/src/qml/compiler/qqmlirbuilder_p.h
+++ b/src/qml/compiler/qqmlirbuilder_p.h
@@ -411,6 +411,7 @@ struct Q_QML_COMPILER_PRIVATE_EXPORT Pragma
         FunctionSignatureBehavior,
         NativeMethodBehavior,
         ValueTypeBehavior,
+        Translator,
     };
 
     enum ListPropertyAssignBehaviorValue
@@ -453,6 +454,7 @@ struct Q_QML_COMPILER_PRIVATE_EXPORT Pragma
         FunctionSignatureBehaviorValue functionSignatureBehavior;
         NativeMethodBehaviorValue nativeMethodBehavior;
         ValueTypeBehaviorValues::Int valueTypeBehavior;
+        uint translationContextIndex;
     };
 
     QV4::CompiledData::Location location;
diff --git a/src/qml/compiler/qv4compiler.cpp b/src/qml/compiler/qv4compiler.cpp
index 34c62cc992..7a7c8f621b 100644
--- a/src/qml/compiler/qv4compiler.cpp
+++ b/src/qml/compiler/qv4compiler.cpp
@@ -682,6 +682,10 @@ QV4::CompiledData::Unit QV4::Compiler::JSUnitGenerator::generateHeader(QV4::Comp
     unit.translationTableSize = translations.size();
     unit.offsetToTranslationTable = nextOffset;
     nextOffset += unit.translationTableSize * sizeof(CompiledData::TranslationData);
+    if (unit.translationTableSize != 0) {
+        constexpr auto spaceForTranslationContextId = sizeof(quint32_le);
+        nextOffset += spaceForTranslationContextId;
+    }
 
     nextOffset = static_cast<quint32>(QtPrivate::roundUpToMultipleOf(8, nextOffset));
 
diff --git a/src/qml/jsruntime/qv4executablecompilationunit.cpp b/src/qml/jsruntime/qv4executablecompilationunit.cpp
index bd43d3cb97..e71568b2d8 100644
--- a/src/qml/jsruntime/qv4executablecompilationunit.cpp
+++ b/src/qml/jsruntime/qv4executablecompilationunit.cpp
@@ -976,11 +976,18 @@ QString ExecutableCompilationUnit::translateFrom(TranslationDataIndex index) con
 
     const bool hasContext
             = translation.contextIndex != QV4::CompiledData::TranslationData::NoContextIndex;
+    QByteArray context;
+    if (hasContext) {
+        context = stringAt(translation.contextIndex).toUtf8();
+    } else {
+        auto pragmaTranslationContext = data->translationContextIndex();
+        context = stringAt(*pragmaTranslationContext).toUtf8();
+        context = context.isEmpty() ? fileContext() : context;
+    }
+
     QByteArray comment = stringAt(translation.commentIndex).toUtf8();
     QByteArray text = stringAt(translation.stringIndex).toUtf8();
-    return QCoreApplication::translate(
-            hasContext ? stringAt(translation.contextIndex).toUtf8() : fileContext(),
-            text, comment, translation.number);
+    return QCoreApplication::translate(context, text, comment, translation.number);
 #endif
 }
 
diff --git a/src/qml/qml/qqmlbuiltinfunctions.cpp b/src/qml/qml/qqmlbuiltinfunctions.cpp
index 1434cffe31..eccf5804cb 100644
--- a/src/qml/qml/qqmlbuiltinfunctions.cpp
+++ b/src/qml/qml/qqmlbuiltinfunctions.cpp
@@ -2171,6 +2171,11 @@ QString GlobalExtensions::currentTranslationContext(ExecutionEngine *engine)
     while (frame && context.isEmpty()) {
         if (CompiledData::CompilationUnitBase *baseUnit = frame->v4Function->compilationUnit) {
             const auto *unit = static_cast<const CompiledData::CompilationUnit *>(baseUnit);
+            auto translationContextIndex = unit->data->translationContextIndex();
+            if (translationContextIndex)
+                context = unit->stringAt(*translationContextIndex);
+            if (!context.isEmpty())
+                break;
             QString fileName = unit->fileName();
             QUrl url(unit->fileName());
             if (url.isValid() && url.isRelative()) {
diff --git a/tests/auto/qml/qqmltranslation/data/pragmacontext.qml b/tests/auto/qml/qqmltranslation/data/pragmacontext.qml
new file mode 100644
index 0000000000..e158cfe4bf
--- /dev/null
+++ b/tests/auto/qml/qqmltranslation/data/pragmacontext.qml
@@ -0,0 +1,8 @@
+import QtQml 2.12
+
+pragma Translator: contextSetWithPragma
+
+QtObject {
+    property string german1: qsTr("English in translation")
+    property string german2: qsTranslate("setContext","English in translation")
+}
diff --git a/tests/auto/qml/qqmltranslation/tst_qqmltranslation.cpp b/tests/auto/qml/qqmltranslation/tst_qqmltranslation.cpp
index edc19edf37..e6e715d006 100644
--- a/tests/auto/qml/qqmltranslation/tst_qqmltranslation.cpp
+++ b/tests/auto/qml/qqmltranslation/tst_qqmltranslation.cpp
@@ -24,6 +24,7 @@ private slots:
     void idTranslation();
     void translationChange();
     void preferJSContext();
+    void pragmaContext();
     void listModel();
 };
 
@@ -175,6 +176,10 @@ class DummyTranslator : public QTranslator
             return QString::fromUtf8("Deutsch in mylibrary");
         if (!qstrcmp(sourceText, "English in translation") && !qstrcmp(context, "nested_js_translation"))
             return QString::fromUtf8("Deutsch in Setzung");
+        if (!qstrcmp(sourceText, "English in translation") && !qstrcmp(context, "contextSetWithPragma"))
+            return QString::fromUtf8("Deutsch in Setzung pragma");
+        if (!qstrcmp(sourceText, "English in translation") && !qstrcmp(context, "setContext"))
+            return QString::fromUtf8("Deutsch in Setzung set");
         if (!qstrcmp(sourceText, "soup"))
             return QString::fromUtf8("Suppe");
         if (!qstrcmp(sourceText, "fish"))
@@ -246,6 +251,24 @@ void tst_qqmltranslation::preferJSContext()
     QCoreApplication::removeTranslator(&translator);
 }
 
+void tst_qqmltranslation::pragmaContext()
+{
+    DummyTranslator translator;
+    QCoreApplication::installTranslator(&translator);
+
+    QQmlEngine engine;
+    QQmlComponent component(&engine, testFileUrl("pragmacontext.qml"));
+    QScopedPointer<QObject> object(component.create());
+    QVERIFY(!object.isNull());
+
+    QCOMPARE(object->property("german1").toString(),
+             QStringLiteral("Deutsch in Setzung pragma"));
+    QCOMPARE(object->property("german2").toString(),
+             QStringLiteral("Deutsch in Setzung set"));
+
+    QCoreApplication::removeTranslator(&translator);
+}
+
 void tst_qqmltranslation::listModel()
 {
     QQmlEngine engine;