Pass the whole IStream wrapper into reporter

This will become useful when reworking colour support, because
Win32 colour support requires checking whether the output is
stdout, which is done through the `IStream` wrapper.

src/catch2/catch_config.cpp

@@ -107,8 +107,8 @@ namespace Catch {
         return m_data.reporterSpecifications;
     }
 
-    std::ostream& Config::getReporterOutputStream(std::size_t reporterIdx) const {
-        return m_reporterStreams.at(reporterIdx)->stream();
+    IStream const* Config::getReporterOutputStream(std::size_t reporterIdx) const {
+        return m_reporterStreams.at(reporterIdx).get();
     }
 
     TestSpec const& Config::testSpec() const { return m_testSpec; }
@@ -118,7 +118,7 @@ namespace Catch {
 
     // IConfig interface
     bool Config::allowThrows() const                   { return !m_data.noThrow; }
-    std::ostream& Config::defaultStream() const        { return m_defaultStream->stream(); }
+    IStream const* Config::defaultStream() const       { return m_defaultStream.get(); }
     StringRef Config::name() const { return m_data.name.empty() ? m_data.processName : m_data.name; }
     bool Config::includeSuccessfulResults() const      { return m_data.showSuccessfulTests; }
     bool Config::warnAboutMissingAssertions() const {

src/catch2/catch_config.hpp

@@ -21,7 +21,7 @@
 
 namespace Catch {
 
-    struct IStream;
+    class IStream;
 
     struct ConfigData {
         struct ReporterAndFile {
@@ -91,7 +91,7 @@ namespace Catch {
         bool listReporters() const;
 
         std::vector<ConfigData::ReporterAndFile> const& getReportersAndOutputFiles() const;
-        std::ostream& getReporterOutputStream(std::size_t reporterIdx) const;
+        IStream const* getReporterOutputStream(std::size_t reporterIdx) const;
 
         std::vector<std::string> const& getTestsOrTags() const override;
         std::vector<std::string> const& getSectionsToRun() const override;
@@ -103,7 +103,7 @@ namespace Catch {
 
         // IConfig interface
         bool allowThrows() const override;
-        std::ostream& defaultStream() const override;
+        IStream const* defaultStream() const override;
         StringRef name() const override;
         bool includeSuccessfulResults() const override;
         bool warnAboutMissingAssertions() const override;

src/catch2/catch_session.cpp

@@ -44,7 +44,7 @@ namespace Catch {
         IStreamingReporterPtr makeReporter(Config const* config) {
             if (Catch::getRegistryHub().getReporterRegistry().getListeners().empty()
                     && config->getReportersAndOutputFiles().size() == 1) {
-                auto& stream = config->getReporterOutputStream(0);
+                auto stream = config->getReporterOutputStream(0);
                 return createReporter(config->getReportersAndOutputFiles()[0].reporterName, ReporterConfig(config, stream));
             }
 
@@ -57,7 +57,7 @@ namespace Catch {
 
             std::size_t reporterIdx = 0;
             for (auto const& reporterAndFile : config->getReportersAndOutputFiles()) {
-                auto& stream = config->getReporterOutputStream(reporterIdx);
+                auto stream = config->getReporterOutputStream(reporterIdx);
                 multi->addReporter(createReporter(reporterAndFile.reporterName, ReporterConfig(config, stream)));
                 reporterIdx++;
             }

src/catch2/interfaces/catch_interfaces_config.hpp

@@ -55,13 +55,14 @@ namespace Catch {
     }; };
 
     class TestSpec;
+    class IStream;
 
     struct IConfig : Detail::NonCopyable {
 
         virtual ~IConfig();
 
         virtual bool allowThrows() const = 0;
-        virtual std::ostream& defaultStream() const = 0;
+        virtual IStream const* defaultStream() const = 0;
         virtual StringRef name() const = 0;
         virtual bool includeSuccessfulResults() const = 0;
         virtual bool shouldDebugBreak() const = 0;

src/catch2/interfaces/catch_interfaces_reporter.cpp

@@ -20,10 +20,10 @@
 
 namespace Catch {
 
-    ReporterConfig::ReporterConfig( IConfig const* _fullConfig, std::ostream& _stream )
-    :   m_stream( &_stream ), m_fullConfig( _fullConfig ) {}
+    ReporterConfig::ReporterConfig( IConfig const* _fullConfig, IStream const* _stream )
+    :   m_stream( _stream ), m_fullConfig( _fullConfig ) {}
 
-    std::ostream& ReporterConfig::stream() const { return *m_stream; }
+    IStream const* ReporterConfig::stream() const { return m_stream; }
     IConfig const * ReporterConfig::fullConfig() const { return m_fullConfig; }
 
     AssertionStats::AssertionStats( AssertionResult const& _assertionResult,

src/catch2/interfaces/catch_interfaces_reporter.hpp

@@ -30,15 +30,16 @@ namespace Catch {
     struct TestCaseInfo;
     class TestCaseHandle;
     struct IConfig;
+    class IStream;
 
     struct ReporterConfig {
-        ReporterConfig( IConfig const* _fullConfig, std::ostream& _stream );
+        ReporterConfig( IConfig const* _fullConfig, IStream const* _stream );
 
-        std::ostream& stream() const;
+        IStream const* stream() const;
         IConfig const* fullConfig() const;
 
     private:
-        std::ostream* m_stream;
+        IStream const* m_stream;
         IConfig const* m_fullConfig;
     };
 

src/catch2/internal/catch_console_colour.cpp

@@ -160,7 +160,7 @@ namespace {
         void setColour( const char* _escapeCode ) {
             // The escape sequence must be flushed to console, otherwise if
             // stdin and stderr are intermixed, we'd get accidentally coloured output.
-            getCurrentContext().getConfig()->defaultStream()
+            getCurrentContext().getConfig()->defaultStream()->stream()
                 << '\033' << _escapeCode << std::flush;
         }
     };

src/catch2/internal/catch_stream.hpp

@@ -22,7 +22,8 @@ namespace Catch {
     std::ostream& cerr();
     std::ostream& clog();
 
-    struct IStream {
+    class IStream {
+    public:
         virtual ~IStream(); // = default
         virtual std::ostream& stream() const = 0;
         // Win32 colour supports requires us to identify whether a stream

src/catch2/reporters/catch_reporter_common_base.hpp

@@ -9,6 +9,7 @@
 #define CATCH_REPORTER_COMMON_BASE_HPP_INCLUDED
 
 #include <catch2/interfaces/catch_interfaces_reporter.hpp>
+#include <catch2/internal/catch_stream.hpp>
 
 namespace Catch {
     /**
@@ -23,13 +24,19 @@ namespace Catch {
      */
     class ReporterBase : public IEventListener {
     protected:
-        //! Stream to write the output to
+        //! The stream wrapper as passed to us by outside code
+        IStream const* m_wrapped_stream;
+        //! Cached output stream from `m_wrapped_stream` to reduce
+        //! number of indirect calls needed to write output.
         std::ostream& m_stream;
 
+
+
     public:
         ReporterBase( ReporterConfig const& config ):
             IEventListener( config.fullConfig() ),
-            m_stream( config.stream() ) {}
+            m_wrapped_stream( config.stream() ),
+            m_stream( m_wrapped_stream->stream() ) {}
 
 
         /**

src/catch2/reporters/catch_reporter_console.cpp

@@ -355,7 +355,7 @@ class TablePrinter {
 
 ConsoleReporter::ConsoleReporter(ReporterConfig const& config)
     : StreamingReporterBase(config),
-    m_tablePrinter(Detail::make_unique<TablePrinter>(config.stream(),
+    m_tablePrinter(Detail::make_unique<TablePrinter>(m_stream,
         [&config]() -> std::vector<ColumnInfo> {
         if (config.fullConfig()->benchmarkNoAnalysis())
         {

src/catch2/reporters/catch_reporter_xml.cpp

@@ -24,7 +24,7 @@
 namespace Catch {
     XmlReporter::XmlReporter( ReporterConfig const& _config )
     :   StreamingReporterBase( _config ),
-        m_xml(_config.stream())
+        m_xml(m_stream)
     {
         m_preferences.shouldRedirectStdOut = true;
         m_preferences.shouldReportAllAssertions = true;

tests/SelfTest/IntrospectiveTests/Reporters.tests.cpp

@@ -16,6 +16,7 @@
 #include <catch2/internal/catch_enforce.hpp>
 #include <catch2/internal/catch_list.hpp>
 #include <catch2/internal/catch_reporter_registry.hpp>
+#include <catch2/internal/catch_stream.hpp>
 #include <catch2/matchers/catch_matchers_string.hpp>
 #include <catch2/reporters/catch_reporter_helpers.hpp>
 #include <catch2/reporters/catch_reporter_event_listener.hpp>
@@ -24,6 +25,16 @@
 
 #include <sstream>
 
+namespace {
+    class StringIStream : public Catch::IStream {
+    public:
+        std::ostream& stream() const override { return sstr; }
+        std::string str() const { return sstr.str(); }
+    private:
+        mutable std::stringstream sstr;
+    };
+}
+
 TEST_CASE( "The default listing implementation write to provided stream",
            "[reporters][reporter-helpers]" ) {
     using Catch::Matchers::ContainsSubstring;
@@ -72,11 +83,11 @@ TEST_CASE( "Reporter's write listings to provided stream", "[reporters]" ) {
 
     for (auto const& factory : factories) {
         INFO("Tested reporter: " << factory.first);
-        std::stringstream sstream;
+        StringIStream sstream;
 
         Catch::ConfigData config_data;
         Catch::Config config( config_data );
-        Catch::ReporterConfig rep_config( &config, sstream );
+        Catch::ReporterConfig rep_config( &config, &sstream );
         auto reporter = factory.second->create( rep_config );
 
         DYNAMIC_SECTION( factory.first << " reporter lists tags" ) {
@@ -162,8 +173,8 @@ TEST_CASE("Multireporter calls reporters and listeners in correct order",
 
     Catch::ConfigData config_data;
     Catch::Config config( config_data );
-    std::stringstream sstream;
-    Catch::ReporterConfig rep_config( &config, sstream );
+    StringIStream sstream;
+    Catch::ReporterConfig rep_config( &config, &sstream );
 
     // We add reporters before listeners, to check that internally they
     // get sorted properly, and listeners are called first anyway.
@@ -215,8 +226,8 @@ TEST_CASE("Multireporter updates ReporterPreferences properly",
 
     Catch::ConfigData config_data;
     Catch::Config config( config_data );
-    std::stringstream sstream;
-    Catch::ReporterConfig rep_config( &config, sstream );
+    StringIStream sstream;
+    Catch::ReporterConfig rep_config( &config, &sstream );
     Catch::MultiReporter multiReporter( &config );
 
     // Post init defaults