Add QStringView/QByteArrayView

View types as function parameters cannot be converted in the standard
way shiboken does it:

QStringView cppArg0;
pythonToCpp(pyArg, &cppArg0);

since they reference some other data.

Introduce a new "viewOn" member to type system entry for them. It
causes the function arguments to be replaced by their viewed-on types
(stringview->string) via metatype.

Add a test in libsample and a test for QUuid::fromString(QStringView).
Test returning QStringView via QRegularExpressionMatch::capturedView().

Task-number: QTBUG-84319
Task-number: PYSIDE-1339
Task-number: PYSIDE-904
Task-number: PYSIDE-487
Change-Id: Iddb4ea268a54928d290e29012e2738772fae83f0
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

9 files changed, 85 insertions, 14 deletions

diff --git a/sources/shiboken2/ApiExtractor/abstractmetabuilder.cpp b/sources/shiboken2/ApiExtractor/abstractmetabuilder.cpp
index 899d910bc..d06a338a3 100644
--- a/sources/shiboken2/ApiExtractor/abstractmetabuilder.cpp
+++ b/sources/shiboken2/ApiExtractor/abstractmetabuilder.cpp
@@ -1884,6 +1884,17 @@ AbstractMetaFunction *AbstractMetaBuilderPrivate::traverseFunction(const Functio
             return nullptr;
         }
 
+        // Add view substitution for simple view types of function arguments
+        // std::string_view -> std::string for foo(std::string_view)
+        auto viewOnTypeEntry = metaType->typeEntry()->viewOn();
+        if (viewOnTypeEntry != nullptr && metaType->indirections() == 0
+            && metaType->arrayElementType() == nullptr
+            && !metaType->hasInstantiations()) {
+            auto viewOn = new AbstractMetaType(*metaType);
+            viewOn->setTypeEntry(viewOnTypeEntry);
+            metaType->setViewOn(viewOn);
+        }
+
         auto *metaArgument = new AbstractMetaArgument;
 
         metaArgument->setType(metaType);
diff --git a/sources/shiboken2/ApiExtractor/abstractmetalang.cpp b/sources/shiboken2/ApiExtractor/abstractmetalang.cpp
index 7d98d9ae8..edb449b04 100644
--- a/sources/shiboken2/ApiExtractor/abstractmetalang.cpp
+++ b/sources/shiboken2/ApiExtractor/abstractmetalang.cpp
@@ -194,10 +194,13 @@ AbstractMetaType::AbstractMetaType() :
 {
 }
 
+AbstractMetaType::AbstractMetaType(const AbstractMetaType &rhs) = default;
+
 AbstractMetaType::~AbstractMetaType()
 {
     qDeleteAll(m_children);
     m_instantiations.clear();
+    delete m_viewOn;
 }
 
 QString AbstractMetaType::package() const
@@ -449,6 +452,8 @@ QDebug operator<<(QDebug d, const AbstractMetaType *at)
                 }
             }
             d << '>';
+            if (at->viewOn())
+                d << ", views " << at->viewOn()->name();
         }
     } else {
         d << '0';
diff --git a/sources/shiboken2/ApiExtractor/abstractmetalang.h b/sources/shiboken2/ApiExtractor/abstractmetalang.h
index 648c792b3..0e187fbcf 100644
--- a/sources/shiboken2/ApiExtractor/abstractmetalang.h
+++ b/sources/shiboken2/ApiExtractor/abstractmetalang.h
@@ -303,6 +303,7 @@ public:
     Q_DECLARE_FLAGS(ComparisonFlags, ComparisonFlag);
 
     AbstractMetaType();
+    AbstractMetaType(const AbstractMetaType &);
     ~AbstractMetaType();
 
     QString package() const;
@@ -530,6 +531,12 @@ public:
 
     bool compare(const AbstractMetaType &rhs, ComparisonFlags = {}) const;
 
+    // View on: Type to use for function argument conversion, fex
+    // std::string_view -> std::string for foo(std::string_view);
+    // cf TypeEntry::viewOn()
+    const AbstractMetaType *viewOn() const { return m_viewOn; }
+    void setViewOn(const AbstractMetaType *v) { m_viewOn = v; }
+
 private:
     TypeUsagePattern determineUsagePattern() const;
     QString formatSignature(bool minimal) const;
@@ -545,6 +552,7 @@ private:
     int m_arrayElementCount = -1;
     const AbstractMetaType *m_arrayElementType = nullptr;
     const AbstractMetaType *m_originalTemplateType = nullptr;
+    const AbstractMetaType *m_viewOn = nullptr;
     Indirections m_indirections;
 
     TypeUsagePattern m_pattern = InvalidPattern;
@@ -555,8 +563,6 @@ private:
 
     ReferenceType m_referenceType = NoReference;
     AbstractMetaTypeList m_children;
-
-    Q_DISABLE_COPY(AbstractMetaType)
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS(AbstractMetaType::ComparisonFlags);
diff --git a/sources/shiboken2/ApiExtractor/messages.cpp b/sources/shiboken2/ApiExtractor/messages.cpp
index 55c51ffa4..a660f7e76 100644
--- a/sources/shiboken2/ApiExtractor/messages.cpp
+++ b/sources/shiboken2/ApiExtractor/messages.cpp
@@ -649,6 +649,12 @@ QString msgIncorrectlyNestedName(const QString &name)
            + name + QLatin1String(").");
 }
 
+QString msgCannotFindView(const QString &viewedName, const QString &name)
+{
+    return QLatin1String("Unable to find viewed type ") + viewedName
+        + QLatin1String(" for ") + name;
+}
+
 // qtdocgenerator.cpp
 
 QString msgTagWarning(const QXmlStreamReader &reader, const QString &context,
diff --git a/sources/shiboken2/ApiExtractor/messages.h b/sources/shiboken2/ApiExtractor/messages.h
index 6c173dc09..55481270c 100644
--- a/sources/shiboken2/ApiExtractor/messages.h
+++ b/sources/shiboken2/ApiExtractor/messages.h
@@ -179,6 +179,8 @@ QString msgNoRootTypeSystemEntry();
 
 QString msgIncorrectlyNestedName(const QString &name);
 
+QString msgCannotFindView(const QString &viewedName, const QString &name);
+
 QString msgCyclicDependency(const QString &funcName, const QString &graphName,
                             const QVector<const AbstractMetaFunction *> &involvedConversions);
 
diff --git a/sources/shiboken2/ApiExtractor/typedatabase.cpp b/sources/shiboken2/ApiExtractor/typedatabase.cpp
index 6aa5513fa..87f5c49df 100644
--- a/sources/shiboken2/ApiExtractor/typedatabase.cpp
+++ b/sources/shiboken2/ApiExtractor/typedatabase.cpp
@@ -894,6 +894,8 @@ void TypeEntry::formatDebug(QDebug &d) const
     FORMAT_BOOL("stream", m_stream)
     FORMAT_LIST_SIZE("codeSnips", m_codeSnips)
     FORMAT_NONEMPTY_STRING("conversionRule", m_conversionRule)
+    if (m_viewOn)
+       d << ", views=" << m_viewOn->name();
     if (!m_version.isNull() && m_version > QVersionNumber(0, 0))
         d << ", version=" << m_version;
     if (m_revision)
diff --git a/sources/shiboken2/ApiExtractor/typesystem.h b/sources/shiboken2/ApiExtractor/typesystem.h
index fa3eae9fc..00f56c51e 100644
--- a/sources/shiboken2/ApiExtractor/typesystem.h
+++ b/sources/shiboken2/ApiExtractor/typesystem.h
@@ -863,6 +863,12 @@ public:
     void setCustomConversion(CustomConversion* customConversion);
     CustomConversion* customConversion() const;
 
+    // View on: Type to use for function argument conversion, fex
+    // std::string_view -> std::string for foo(std::string_view).
+    // cf AbstractMetaType::viewOn()
+    TypeEntry *viewOn() const { return m_viewOn; }
+    void setViewOn(TypeEntry *v) { m_viewOn = v; }
+
     virtual TypeEntry *clone() const;
 
     void useAsTypedef(const TypeEntry *source);
@@ -898,6 +904,7 @@ private:
     CustomConversion *m_customConversion = nullptr;
     SourceLocation m_sourceLocation; // XML file
     uint m_codeGeneration = GenerateAll;
+    TypeEntry *m_viewOn = nullptr;
     int m_revision = 0;
     int m_sbkIndex = 0;
     Type m_type;
diff --git a/sources/shiboken2/ApiExtractor/typesystemparser.cpp b/sources/shiboken2/ApiExtractor/typesystemparser.cpp
index b71a247f3..7323e01f6 100644
--- a/sources/shiboken2/ApiExtractor/typesystemparser.cpp
+++ b/sources/shiboken2/ApiExtractor/typesystemparser.cpp
@@ -1112,16 +1112,44 @@ bool TypeSystemParser::checkRootElement()
     return ok;
 }
 
-void TypeSystemParser::applyCommonAttributes(const QXmlStreamReader &reader, TypeEntry *type,
-                                             QXmlStreamAttributes *attributes) const
+static TypeEntry *findViewedType(const QString &name)
+{
+    const auto range = TypeDatabase::instance()->entries().equal_range(name);
+    for (auto i = range.first; i != range.second; ++i) {
+        switch (i.value()->type()) {
+        case TypeEntry::BasicValueType:
+        case TypeEntry::PrimitiveType:
+        case TypeEntry::ContainerType:
+        case TypeEntry::ObjectType:
+            return i.value();
+        default:
+            break;
+        }
+    }
+    return nullptr;
+}
+
+bool TypeSystemParser::applyCommonAttributes(const QXmlStreamReader &reader, TypeEntry *type,
+                                             QXmlStreamAttributes *attributes)
 {
     type->setSourceLocation(SourceLocation(m_currentFile,
                                            reader.lineNumber()));
     type->setCodeGeneration(m_generate);
-    const int revisionIndex =
-        indexOfAttribute(*attributes, u"revision");
-    if (revisionIndex != -1)
-        type->setRevision(attributes->takeAt(revisionIndex).value().toInt());
+    for (int i = attributes->size() - 1; i >= 0; --i) {
+        const auto name = attributes->at(i).qualifiedName();
+        if (name ==  u"revision") {
+            type->setRevision(attributes->takeAt(i).value().toInt());
+        } else if (name == u"view-on") {
+            const QString name = attributes->takeAt(i).value().toString();
+            TypeEntry *views = findViewedType(name);
+            if (views == nullptr) {
+                m_error = msgCannotFindView(name, type->name());
+                return false;
+            }
+            type->setViewOn(views);
+        }
+    }
+    return true;
 }
 
 FlagsTypeEntry *
@@ -1146,7 +1174,8 @@ FlagsTypeEntry *
     }
 
     ftype->setOriginalName(flagName);
-    applyCommonAttributes(reader, ftype, attributes);
+    if (!applyCommonAttributes(reader, ftype, attributes))
+        return nullptr;
 
     QStringList lst = flagName.split(colonColon());
     const QString targetLangFlagName = QStringList(lst.mid(0, lst.size() - 1)).join(QLatin1Char('.'));
@@ -1225,7 +1254,8 @@ SmartPointerTypeEntry *
 
     auto *type = new SmartPointerTypeEntry(name, getter, smartPointerType,
                                            refCountMethodName, since, currentParentTypeEntry());
-    applyCommonAttributes(reader, type, attributes);
+    if (!applyCommonAttributes(reader, type, attributes))
+        return nullptr;
     m_smartPointerInstantiations.insert(type, instantiations);
     return type;
 }
@@ -1238,7 +1268,8 @@ PrimitiveTypeEntry *
     if (!checkRootElement())
         return nullptr;
     auto *type = new PrimitiveTypeEntry(name, since, currentParentTypeEntry());
-    applyCommonAttributes(reader, type, attributes);
+    if (!applyCommonAttributes(reader, type, attributes))
+        return nullptr;
     for (int i = attributes->size() - 1; i >= 0; --i) {
         const auto name = attributes->at(i).qualifiedName();
         if (name == targetLangNameAttribute()) {
@@ -1282,7 +1313,8 @@ ContainerTypeEntry *
         return nullptr;
     }
     auto *type = new ContainerTypeEntry(name, containerType, since, currentParentTypeEntry());
-    applyCommonAttributes(reader, type, attributes);
+    if (!applyCommonAttributes(reader, type, attributes))
+        return nullptr;
     return type;
 }
 
diff --git a/sources/shiboken2/ApiExtractor/typesystemparser.h b/sources/shiboken2/ApiExtractor/typesystemparser.h
index 3eaa74f04..130d8d3d2 100644
--- a/sources/shiboken2/ApiExtractor/typesystemparser.h
+++ b/sources/shiboken2/ApiExtractor/typesystemparser.h
@@ -169,8 +169,8 @@ private:
 
     const TypeEntry *currentParentTypeEntry() const;
     bool checkRootElement();
-    void applyCommonAttributes(const QXmlStreamReader &reader, TypeEntry *type,
-                               QXmlStreamAttributes *attributes) const;
+    bool applyCommonAttributes(const QXmlStreamReader &reader, TypeEntry *type,
+                               QXmlStreamAttributes *attributes);
     PrimitiveTypeEntry *
         parsePrimitiveTypeEntry(const QXmlStreamReader &, const QString &name,
                                 const QVersionNumber &since, QXmlStreamAttributes *);