Make IStream::stream non-const

This way it makes much more sense from logically-const point
of view, and also means that concrete implementations don't
have to always have a `mutable` keyword on the stream member.

src/catch2/catch_config.cpp

@@ -108,8 +108,8 @@ namespace Catch {
         return m_data.reporterSpecifications;
     }
 
-    IStream const* Config::getReporterOutputStream(std::size_t reporterIdx) const {
+    IStream* Config::getReporterOutputStream(std::size_t reporterIdx) const {
-        return m_reporterStreams.at(reporterIdx).get();
+        return const_cast<IStream*>(m_reporterStreams.at(reporterIdx).get());
     }
 
     TestSpec const& Config::testSpec() const { return m_testSpec; }

src/catch2/catch_config.hpp

@@ -81,7 +81,7 @@ namespace Catch {
         bool listReporters() const;
 
         std::vector<ReporterSpec> const& getReporterSpecs() const;
-        IStream const* getReporterOutputStream(std::size_t reporterIdx) const;
+        IStream* getReporterOutputStream(std::size_t reporterIdx) const;
 
         std::vector<std::string> const& getTestsOrTags() const override;
         std::vector<std::string> const& getSectionsToRun() const override;
@@ -118,7 +118,7 @@ namespace Catch {
     private:
         ConfigData m_data;
 
-        std::vector<Detail::unique_ptr<IStream const>> m_reporterStreams;
+        std::vector<Detail::unique_ptr<IStream>> m_reporterStreams;
         TestSpec m_testSpec;
         bool m_hasTestFilters = false;
     };

src/catch2/interfaces/catch_interfaces_reporter.cpp

@@ -23,7 +23,7 @@ namespace Catch {
 
     ReporterConfig::ReporterConfig(
         IConfig const* _fullConfig,
-        IStream const* _stream,
+        IStream* _stream,
         ColourMode colourMode,
         std::map<std::string, std::string> customOptions ):
         m_stream( _stream ),
@@ -31,7 +31,7 @@ namespace Catch {
         m_colourMode( colourMode ),
         m_customOptions( CATCH_MOVE( customOptions ) ) {}
 
-    IStream const* ReporterConfig::stream() const { return m_stream; }
+    IStream* ReporterConfig::stream() const { return m_stream; }
     IConfig const * ReporterConfig::fullConfig() const { return m_fullConfig; }
     ColourMode ReporterConfig::colourMode() const { return m_colourMode; }
 

src/catch2/interfaces/catch_interfaces_reporter.hpp

@@ -36,17 +36,17 @@ namespace Catch {
 
     struct ReporterConfig {
         ReporterConfig( IConfig const* _fullConfig,
-                        IStream const* _stream,
+                        IStream* _stream,
                         ColourMode colourMode,
                         std::map<std::string, std::string> customOptions );
 
-        IStream const* stream() const;
+        IStream* stream() const;
         IConfig const* fullConfig() const;
         ColourMode colourMode() const;
         std::map<std::string, std::string> const& customOptions() const;
 
     private:
-        IStream const* m_stream;
+        IStream* m_stream;
         IConfig const* m_fullConfig;
         ColourMode m_colourMode;
         std::map<std::string, std::string> m_customOptions;

src/catch2/internal/catch_console_colour.cpp

@@ -84,7 +84,7 @@ namespace Catch {
         //! platforms, and when the user asks to deactivate all colours.
         class NoColourImpl : public ColourImpl {
         public:
-            NoColourImpl( IStream const* stream ): ColourImpl( stream ) {}
+            NoColourImpl( IStream* stream ): ColourImpl( stream ) {}
             static bool useColourOnPlatform() { return true; }
 
         private:
@@ -103,7 +103,7 @@ namespace {
 
     class Win32ColourImpl : public ColourImpl {
     public:
-        Win32ColourImpl(IStream const* stream):
+        Win32ColourImpl(IStream* stream):
             ColourImpl(stream) {
             CONSOLE_SCREEN_BUFFER_INFO csbiInfo;
             GetConsoleScreenBufferInfo( GetStdHandle( STD_OUTPUT_HANDLE ),
@@ -169,7 +169,7 @@ namespace {
 
     class ANSIColourImpl : public ColourImpl {
     public:
-        ANSIColourImpl( IStream const* stream ): ColourImpl( stream ) {}
+        ANSIColourImpl( IStream* stream ): ColourImpl( stream ) {}
 
         static bool useColourOnPlatform(IStream const& stream) {
             // This is kinda messy due to trying to support a bunch of
@@ -229,7 +229,7 @@ namespace {
 namespace Catch {
 
     Detail::unique_ptr<ColourImpl> makeColourImpl( ColourMode implSelection,
-                                                   IStream const* stream ) {
+                                                   IStream* stream ) {
         if ( implSelection == ColourMode::None ) {
             return Detail::make_unique<NoColourImpl>( stream );
         }

src/catch2/internal/catch_console_colour.hpp

@@ -60,9 +60,9 @@ namespace Catch {
     class ColourImpl {
     protected:
         //! The associated stream of this ColourImpl instance
-        IStream const* m_stream;
+        IStream* m_stream;
     public:
-        ColourImpl( IStream const* stream ): m_stream( stream ) {}
+        ColourImpl( IStream* stream ): m_stream( stream ) {}
 
         //! RAII wrapper around writing specific colour of text using specific
         //! colour impl into a stream.
@@ -131,7 +131,7 @@ namespace Catch {
 
     //! Provides ColourImpl based on global config and target compilation platform
     Detail::unique_ptr<ColourImpl> makeColourImpl( ColourMode colourSelection,
-                                                   IStream const* stream );
+                                                   IStream* stream );
 
     //! Checks if specific colour impl has been compiled into the binary
     bool isColourImplAvailable( ColourMode colourSelection );

src/catch2/internal/catch_stream.cpp

@@ -74,7 +74,7 @@ namespace Detail {
         ///////////////////////////////////////////////////////////////////////////
 
         class FileStream : public IStream {
-            mutable std::ofstream m_ofs;
+            std::ofstream m_ofs;
         public:
             FileStream( std::string const& filename ) {
                 m_ofs.open( filename.c_str() );
@@ -82,7 +82,7 @@ namespace Detail {
             }
             ~FileStream() override = default;
         public: // IStream
-            std::ostream& stream() const override {
+            std::ostream& stream() override {
                 return m_ofs;
             }
         };
@@ -90,7 +90,7 @@ namespace Detail {
         ///////////////////////////////////////////////////////////////////////////
 
         class CoutStream : public IStream {
-            mutable std::ostream m_os;
+            std::ostream m_os;
         public:
             // Store the streambuf from cout up-front because
             // cout may get redirected when running tests
@@ -98,12 +98,12 @@ namespace Detail {
             ~CoutStream() override = default;
 
         public: // IStream
-            std::ostream& stream() const override { return m_os; }
+            std::ostream& stream() override { return m_os; }
             bool isConsole() const override { return true; }
         };
 
         class CerrStream : public IStream {
-            mutable std::ostream m_os;
+            std::ostream m_os;
 
         public:
             // Store the streambuf from cerr up-front because
@@ -112,7 +112,7 @@ namespace Detail {
             ~CerrStream() override = default;
 
         public: // IStream
-            std::ostream& stream() const override { return m_os; }
+            std::ostream& stream() override { return m_os; }
             bool isConsole() const override { return true; }
         };
 
@@ -120,7 +120,7 @@ namespace Detail {
 
         class DebugOutStream : public IStream {
             Detail::unique_ptr<StreamBufImpl<OutputDebugWriter>> m_streamBuf;
-            mutable std::ostream m_os;
+            std::ostream m_os;
         public:
             DebugOutStream()
             :   m_streamBuf( Detail::make_unique<StreamBufImpl<OutputDebugWriter>>() ),
@@ -130,7 +130,7 @@ namespace Detail {
             ~DebugOutStream() override = default;
 
         public: // IStream
-            std::ostream& stream() const override { return m_os; }
+            std::ostream& stream() override { return m_os; }
         };
 
     } // unnamed namespace
@@ -138,7 +138,7 @@ namespace Detail {
 
     ///////////////////////////////////////////////////////////////////////////
 
-    auto makeStream( std::string const& filename ) -> Detail::unique_ptr<IStream const> {
+    auto makeStream( std::string const& filename ) -> Detail::unique_ptr<IStream> {
         if ( filename.empty() || filename == "-" ) {
             return Detail::make_unique<Detail::CoutStream>();
         }

src/catch2/internal/catch_stream.hpp

@@ -25,7 +25,7 @@ namespace Catch {
     class IStream {
     public:
         virtual ~IStream(); // = default
-        virtual std::ostream& stream() const = 0;
+        virtual std::ostream& stream() = 0;
         /**
          * Best guess on whether the instance is writing to a console (e.g. via stdout/stderr)
          *
@@ -51,7 +51,7 @@ namespace Catch {
      *
      * \throws if passed an unrecognized %-prefixed stream
      */
-    auto makeStream( std::string const& filename ) -> Detail::unique_ptr<IStream const>;
+    auto makeStream( std::string const& filename ) -> Detail::unique_ptr<IStream>;
 
     class ReusableStringStream : Detail::NonCopyable {
         std::size_t m_index;

src/catch2/reporters/catch_reporter_common_base.hpp

@@ -29,7 +29,7 @@ namespace Catch {
     class ReporterBase : public IEventListener {
     protected:
         //! The stream wrapper as passed to us by outside code
-        IStream const* m_wrapped_stream;
+        IStream* m_wrapped_stream;
         //! Cached output stream from `m_wrapped_stream` to reduce
         //! number of indirect calls needed to write output.
         std::ostream& m_stream;

tests/SelfTest/IntrospectiveTests/ColourImpl.tests.cpp

@@ -21,9 +21,9 @@ namespace {
     };
 
     class TestStringStream : public Catch::IStream {
-        mutable std::stringstream m_stream;
+        std::stringstream m_stream;
     public:
-        std::ostream& stream() const override {
+        std::ostream& stream() override {
             return m_stream;
         }
 

tests/SelfTest/IntrospectiveTests/Reporters.tests.cpp

@@ -29,10 +29,10 @@
 namespace {
     class StringIStream : public Catch::IStream {
     public:
-        std::ostream& stream() const override { return sstr; }
+        std::ostream& stream() override { return sstr; }
         std::string str() const { return sstr.str(); }
     private:
-        mutable std::stringstream sstr;
+        std::stringstream sstr;
     };
 }