Add JSON reporter (#2706)

Co-authored-by: Martin Hořeňovský <martin.horenovsky@gmail.com>

3 files changed, 242 insertions, 1 deletions

diff --git a/src/catch2/internal/catch_jsonwriter.cpp b/src/catch2/internal/catch_jsonwriter.cpp
new file mode 100644
index 00000000..f6c279d8
--- /dev/null
+++ b/src/catch2/internal/catch_jsonwriter.cpp
@@ -0,0 +1,115 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+#include <catch2/internal/catch_enforce.hpp>
+#include <catch2/internal/catch_jsonwriter.hpp>
+
+namespace Catch {
+    void JsonUtils::indent( std::ostream& os, std::uint64_t level ) {
+        for ( std::uint64_t i = 0; i < level; ++i ) {
+            os << "  ";
+        }
+    }
+    void JsonUtils::appendCommaNewline( std::ostream& os,
+                                        bool& should_comma,
+                                        std::uint64_t level ) {
+        if ( should_comma ) { os << ','; }
+        should_comma = true;
+        os << '\n';
+        indent( os, level );
+    }
+
+    JsonObjectWriter::JsonObjectWriter( std::ostream& os ):
+        JsonObjectWriter{ os, 0 } {}
+
+    JsonObjectWriter::JsonObjectWriter( std::ostream& os,
+                                        std::uint64_t indent_level ):
+        m_os{ os }, m_indent_level{ indent_level } {
+        m_os << "{";
+    }
+    JsonObjectWriter::JsonObjectWriter( JsonObjectWriter&& source ):
+        m_os{ source.m_os },
+        m_indent_level{ source.m_indent_level },
+        m_should_comma{ source.m_should_comma },
+        m_active{ source.m_active } {
+        source.m_active = false;
+    }
+
+    JsonObjectWriter::~JsonObjectWriter() {
+        if ( !m_active ) { return; }
+
+        m_os << '\n';
+        JsonUtils::indent( m_os, m_indent_level );
+        m_os << '}';
+    }
+
+    JsonValueWriter JsonObjectWriter::write( std::string const& key ) {
+        JsonUtils::appendCommaNewline(
+            m_os, m_should_comma, m_indent_level + 1 );
+
+        m_os << '"' << key << '"' << ": ";
+        return JsonValueWriter{ m_os, m_indent_level + 1 };
+    }
+
+    JsonArrayWriter::JsonArrayWriter( std::ostream& os ):
+        JsonArrayWriter{ os, 0 } {}
+    JsonArrayWriter::JsonArrayWriter( std::ostream& os,
+                                      std::uint64_t indent_level ):
+        m_os{ os }, m_indent_level{ indent_level } {
+        m_os << "[";
+    }
+    JsonArrayWriter::JsonArrayWriter( JsonArrayWriter&& source ):
+        m_os{ source.m_os },
+        m_indent_level{ source.m_indent_level },
+        m_should_comma{ source.m_should_comma },
+        m_active{ source.m_active } {
+        source.m_active = false;
+    }
+    JsonArrayWriter::~JsonArrayWriter() {
+        if ( !m_active ) { return; }
+
+        m_os << '\n';
+        JsonUtils::indent( m_os, m_indent_level );
+        m_os << ']';
+    }
+
+    JsonObjectWriter JsonArrayWriter::writeObject() {
+        JsonUtils::appendCommaNewline(
+            m_os, m_should_comma, m_indent_level + 1 );
+        return JsonObjectWriter{ m_os, m_indent_level + 1 };
+    }
+
+    JsonArrayWriter JsonArrayWriter::writeArray() {
+        JsonUtils::appendCommaNewline(
+            m_os, m_should_comma, m_indent_level + 1 );
+        return JsonArrayWriter{ m_os, m_indent_level + 1 };
+    }
+
+    JsonArrayWriter& JsonArrayWriter::write( bool value ) {
+        return writeImpl( value );
+    }
+
+    JsonValueWriter::JsonValueWriter( std::ostream& os ):
+        JsonValueWriter{ os, 0 } {}
+
+    JsonValueWriter::JsonValueWriter( std::ostream& os,
+                                      std::uint64_t indent_level ):
+        m_os{ os }, m_indent_level{ indent_level } {}
+
+    JsonObjectWriter JsonValueWriter::writeObject() && {
+        return JsonObjectWriter{ m_os, m_indent_level };
+    }
+
+    JsonArrayWriter JsonValueWriter::writeArray() && {
+        return JsonArrayWriter{ m_os, m_indent_level };
+    }
+
+    void JsonValueWriter::write( bool value ) && {
+        writeImpl( value ? "true" : "false", false );
+    }
+
+} // namespace Catch
diff --git a/src/catch2/internal/catch_jsonwriter.hpp b/src/catch2/internal/catch_jsonwriter.hpp
new file mode 100644
index 00000000..9cac3de6
--- /dev/null
+++ b/src/catch2/internal/catch_jsonwriter.hpp
@@ -0,0 +1,123 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+#ifndef CATCH_JSONWRITER_HPP_INCLUDED
+#define CATCH_JSONWRITER_HPP_INCLUDED
+
+#include <catch2/internal/catch_reusable_string_stream.hpp>
+#include <catch2/internal/catch_stringref.hpp>
+
+#include <cstdint>
+#include <sstream>
+
+namespace Catch {
+    class JsonObjectWriter;
+    class JsonArrayWriter;
+
+    struct JsonUtils {
+        static void indent( std::ostream& os, std::uint64_t level );
+        static void appendCommaNewline( std::ostream& os,
+                                        bool& should_comma,
+                                        std::uint64_t level );
+    };
+
+    class JsonValueWriter {
+    public:
+        JsonValueWriter( std::ostream& os );
+        JsonValueWriter( std::ostream& os, std::uint64_t indent_level );
+
+        JsonObjectWriter writeObject() &&;
+        JsonArrayWriter writeArray() &&;
+
+        template <typename T>
+        void write( T const& value ) && {
+            writeImpl( value, !std::is_arithmetic<T>::value );
+        }
+
+        void write( bool value ) &&;
+
+    private:
+        template <typename T>
+        void writeImpl( T const& value, bool quote_value ) {
+            if ( quote_value ) { m_os << '"'; }
+            m_sstream << value;
+            while ( true ) {
+                char c = m_sstream.get();
+
+                if ( m_sstream.eof() ) { break; }
+                if ( c == '"' ) {
+                    m_os << '\\' << '"';
+                } else {
+                    m_os << c;
+                }
+            }
+            if ( quote_value ) { m_os << '"'; }
+        }
+
+        std::ostream& m_os;
+        std::stringstream m_sstream{};
+        std::uint64_t m_indent_level;
+    };
+
+    class JsonObjectWriter {
+    public:
+        JsonObjectWriter( std::ostream& os );
+        JsonObjectWriter( std::ostream& os, std::uint64_t indent_level );
+
+        JsonObjectWriter( JsonObjectWriter&& source );
+        JsonObjectWriter& operator=( JsonObjectWriter&& source ) = delete;
+
+        ~JsonObjectWriter();
+
+        JsonValueWriter write( std::string const& key );
+
+    private:
+        std::ostream& m_os;
+        std::uint64_t m_indent_level;
+        bool m_should_comma = false;
+        bool m_active = true;
+    };
+
+    class JsonArrayWriter {
+    public:
+        JsonArrayWriter( std::ostream& os );
+        JsonArrayWriter( std::ostream& os, std::uint64_t indent_level );
+
+        JsonArrayWriter( JsonArrayWriter&& source );
+        JsonArrayWriter& operator=( JsonArrayWriter&& source ) = delete;
+
+        ~JsonArrayWriter();
+
+        JsonObjectWriter writeObject();
+        JsonArrayWriter writeArray();
+
+        template <typename T>
+        JsonArrayWriter& write( T const& value ) {
+            return writeImpl( value );
+        }
+
+        JsonArrayWriter& write( bool value );
+
+    private:
+        template <typename T>
+        JsonArrayWriter& writeImpl( T const& value ) {
+            JsonUtils::appendCommaNewline(
+                m_os, m_should_comma, m_indent_level + 1 );
+            JsonValueWriter{ m_os }.write( value );
+
+            return *this;
+        }
+
+        std::ostream& m_os;
+        std::uint64_t m_indent_level;
+        bool m_should_comma = false;
+        bool m_active = true;
+    };
+
+} // namespace Catch
+
+#endif // CATCH_JSONWRITER_HPP_INCLUDED
diff --git a/src/catch2/internal/catch_reporter_registry.cpp b/src/catch2/internal/catch_reporter_registry.cpp
index b2b0cd07..cea8c4dc 100644
--- a/src/catch2/internal/catch_reporter_registry.cpp
+++ b/src/catch2/internal/catch_reporter_registry.cpp
@@ -6,13 +6,14 @@
 
 // SPDX-License-Identifier: BSL-1.0
 
-#include <catch2/internal/catch_reporter_registry.hpp>
 #include <catch2/interfaces/catch_interfaces_reporter_factory.hpp>
 #include <catch2/internal/catch_enforce.hpp>
 #include <catch2/internal/catch_move_and_forward.hpp>
+#include <catch2/internal/catch_reporter_registry.hpp>
 #include <catch2/reporters/catch_reporter_automake.hpp>
 #include <catch2/reporters/catch_reporter_compact.hpp>
 #include <catch2/reporters/catch_reporter_console.hpp>
+#include <catch2/reporters/catch_reporter_json.hpp>
 #include <catch2/reporters/catch_reporter_junit.hpp>
 #include <catch2/reporters/catch_reporter_registrars.hpp>
 #include <catch2/reporters/catch_reporter_sonarqube.hpp>
@@ -47,6 +48,8 @@ namespace Catch {
             Detail::make_unique<ReporterFactory<TeamCityReporter>>();
         m_impl->factories["XML"] =
             Detail::make_unique<ReporterFactory<XmlReporter>>();
+        m_impl->factories["JSON"] =
+            Detail::make_unique<ReporterFactory<JsonReporter>>();
     }
 
     ReporterRegistry::~ReporterRegistry() = default;