Clang: Improve interfaces

The interfaces should never used to handle ownership. So it is now using
protected destructors. Copy operations are forbidden too.

https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#c35-a-base-class-destructor-should-be-either-public-and-virtual-or-protected-and-nonvirtual

Change-Id: Ib0b60a73a7ec130973b5cb0095cc5b2f10fa0758
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/libs/sqlite/sqlite-lib.pri

@@ -17,7 +17,6 @@ SOURCES += \
     $$PWD/sqliteglobal.cpp \
     $$PWD/sqlitereadstatement.cpp \
     $$PWD/sqlitereadwritestatement.cpp \
-    $$PWD/sqlitetransaction.cpp \
     $$PWD/sqlitewritestatement.cpp \
     $$PWD/sqlstatementbuilder.cpp \
     $$PWD/sqlstatementbuilderexception.cpp \

src/libs/sqlite/sqlitebasestatement.h

@@ -53,6 +53,9 @@ class SQLITE_EXPORT BaseStatement
 public:
     explicit BaseStatement(Utils::SmallStringView sqlStatement, Database &database);
 
+    BaseStatement(const BaseStatement &) = delete;
+    BaseStatement &operator=(const BaseStatement &) = delete;
+
     static void deleteCompiledStatement(sqlite3_stmt *m_compiledStatement);
 
     bool next() const;
@@ -123,6 +126,9 @@ public:
 
     Database &database() const;
 
+protected:
+    ~BaseStatement() = default;
+
 private:
     std::unique_ptr<sqlite3_stmt, void (*)(sqlite3_stmt*)> m_compiledStatement;
     Database &m_database;
@@ -146,7 +152,7 @@ extern template SQLITE_EXPORT Utils::SmallString BaseStatement::fetchValue<Utils
 extern template SQLITE_EXPORT Utils::PathString BaseStatement::fetchValue<Utils::PathString>(int column) const;
 
 template <typename BaseStatement>
-class SQLITE_EXPORT StatementImplementation : public BaseStatement
+class StatementImplementation : public BaseStatement
 {
 
 public:
@@ -290,6 +296,8 @@ public:
         return statement.template fetchValue<Type>(0);
     }
 
+protected:
+    ~StatementImplementation() = default;
 
 private:
     struct Resetter

src/libs/sqlite/sqlitedatabase.h

@@ -55,10 +55,7 @@ public:
     Database(Utils::PathString &&databaseFilePath, JournalMode journalMode=JournalMode::Wal);
 
     Database(const Database &) = delete;
-    bool operator=(const Database &) = delete;
-
-    Database(Database &&) = delete;
-    bool operator=(Database &&) = delete;
+    Database &operator=(const Database &) = delete;
 
     void open();
     void open(Utils::PathString &&databaseFilePath);

src/libs/sqlite/sqlitetransaction.h

@@ -35,11 +35,10 @@ namespace Sqlite {
 class DatabaseBackend;
 class Database;
 
-class SQLITE_EXPORT TransactionInterface
+class TransactionInterface
 {
 public:
     TransactionInterface() = default;
-    virtual ~TransactionInterface();
     TransactionInterface(const TransactionInterface &) = delete;
     TransactionInterface &operator=(const TransactionInterface &) = delete;
 
@@ -48,6 +47,9 @@ public:
     virtual void exclusiveBegin() = 0;
     virtual void commit() = 0;
     virtual void rollback() = 0;
+
+protected:
+    ~TransactionInterface() = default;
 };
 
 class AbstractTransaction
@@ -63,6 +65,7 @@ public:
     }
 
 protected:
+    ~AbstractTransaction() = default;
     AbstractTransaction(TransactionInterface &interface)
         : m_interface(interface)
     {
@@ -76,6 +79,8 @@ protected:
 class AbstractThrowingTransaction : public AbstractTransaction
 {
 public:
+    AbstractThrowingTransaction(const AbstractThrowingTransaction &) = delete;
+    AbstractThrowingTransaction &operator=(const AbstractThrowingTransaction &) = delete;
     ~AbstractThrowingTransaction() noexcept(false)
     {
         try {
@@ -97,6 +102,8 @@ protected:
 class AbstractNonThrowingDestructorTransaction : public AbstractTransaction
 {
 public:
+    AbstractNonThrowingDestructorTransaction(const AbstractNonThrowingDestructorTransaction &) = delete;
+    AbstractNonThrowingDestructorTransaction &operator=(const AbstractNonThrowingDestructorTransaction &) = delete;
     ~AbstractNonThrowingDestructorTransaction()
     {
         try {