Give Catch3 its own build names and headers

Catch2 compatibility means the API tests are written in: the macros, such
as TEST_CASE and REQUIRE, and the Catch:: namespace. It does not mean
Catch2's build names or header paths. find_package(Catch2) found Catch3,
and a project using both frameworks met two packages, two sets of targets,
two Catch.cmake modules and two catch2/ header trees with the same names.

Build names:
- CMake: project and package Catch3, targets Catch3::Catch3 and
  Catch3::Catch3WithMain, libraries Catch3 and Catch3Main, options
  CATCH3_*, lib/cmake/Catch3 with Catch3Config, and pkg-config catch3 and
  catch3-with-main. The version is Catch3's, 0.3.0, compatible within a
  minor version.
- The CMake scripts are Catch3.cmake (catch3_discover_tests),
  Catch3AddTests.cmake and Catch3ShardTests.cmake
  (catch3_add_sharded_tests); the helpers they define at ctest time have a
  catch3_ prefix. ParseAndAddCatchTests.cmake, deprecated upstream, is gone.
- Bazel //:catch3 and //:catch3_main, Meson catch3 and catch3-with-main
  (with override_dependency), Xmake catch3 and catch3_main, Premake Catch3
  and Catch3WithMain. Visual Studio projects get GUIDs of their own.
- The Progmasoft::Catch3 target and package are gone: property testing
  and snapshots are part of Catch3::Catch3. Their sources now build with
  the library's warning flags, so property failures are built field by
  field (no missing initializers) and the default property name is a
  thread-local pointer to the name its scope owns (no global destructor).

Headers: the engine moved from src/catch2 to src/Progmasoft/Catch3 with
Progmasoft names, so <catch2/catch_test_macros.hpp> is
<Progmasoft/Catch3/TestMacros.hpp>, <catch2/matchers/catch_matchers_string.hpp>
is <Progmasoft/Catch3/Matchers/String.hpp>, and interface headers are named
after their interface, such as Interfaces/IConfig.hpp. Include guards
became #pragma once. The installed headers go to include/Progmasoft.
src/Progmasoft/Context.cpp is StrategyContext.cpp, so no two sources share
a file name.

tools/scripts/upstreamFiles.txt lists the files that come from Catch2.
The license check expects BSL-1.0 on them and Progmasoft's header on the
rest of src/Progmasoft; the convenience-header check, the amalgamation
script and the surrogate tests take the engine's headers from it. The
amalgamated files are regenerated. The header-guard workflow checks for
#pragma once instead of checkguard.

Documents, the README and the release notes describe the new names.

1 files changed, 74 insertions, 0 deletions

diff --git a/src/Progmasoft/Catch3/Internal/ReusableStringStream.cpp b/src/Progmasoft/Catch3/Internal/ReusableStringStream.cpp
new file mode 100644
index 00000000..6713fb0d
--- /dev/null
+++ b/src/Progmasoft/Catch3/Internal/ReusableStringStream.cpp
@@ -0,0 +1,74 @@
+
+//              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 <Progmasoft/Catch3/Internal/ReusableStringStream.hpp>
+#include <Progmasoft/Catch3/Internal/Singletons.hpp>
+#include <Progmasoft/Catch3/Internal/ThreadSupport.hpp>
+#include <Progmasoft/Catch3/Internal/UniquePtr.hpp>
+
+#include <cstdio>
+#include <list>
+#include <sstream>
+#include <tuple>
+#include <vector>
+
+namespace Catch {
+
+    // This class encapsulates the idea of a pool of ostringstreams that can be reused.
+    struct StringStreams {
+        std::vector<Detail::unique_ptr<std::ostringstream>> m_streams;
+        // The library can be linked into ASan-instrumented clients without
+        // instrumenting Catch3 itself. A list avoids mixed-mode libc++ vector
+        // container annotations for the reusable-index pool.
+        std::list<std::size_t> m_unused;
+        std::ostringstream m_referenceStream; // Used for copy state/ flags from
+        Detail::Mutex m_mutex;
+
+        auto add() -> std::pair<std::size_t, std::ostringstream*> {
+            Detail::LockGuard _( m_mutex );
+            if( m_unused.empty() ) {
+                m_streams.push_back( Detail::make_unique<std::ostringstream>() );
+                return { m_streams.size()-1, m_streams.back().get() };
+            }
+            else {
+                auto index = m_unused.back();
+                m_unused.pop_back();
+                return { index, m_streams[index].get() };
+            }
+        }
+
+        void release( std::size_t index, std::ostream* originalPtr ) {
+            assert( originalPtr );
+            originalPtr->copyfmt( m_referenceStream );  // Restore initial flags and other state
+
+            Detail::LockGuard _( m_mutex );
+            assert( originalPtr == m_streams[index].get() && "Mismatch between release index and stream ptr" );
+            m_unused.push_back( index );
+        }
+    };
+
+    ReusableStringStream::ReusableStringStream() {
+        std::tie( m_index, m_oss ) =
+            Singleton<StringStreams>::getMutable().add();
+    }
+
+    ReusableStringStream::~ReusableStringStream() {
+        static_cast<std::ostringstream*>( m_oss )->str("");
+        m_oss->clear();
+        Singleton<StringStreams>::getMutable().release( m_index, m_oss );
+    }
+
+    std::string ReusableStringStream::str() const {
+        return static_cast<std::ostringstream*>( m_oss )->str();
+    }
+
+    void ReusableStringStream::str( std::string const& str ) {
+        static_cast<std::ostringstream*>( m_oss )->str( str );
+    }
+
+
+}