debug: Add TypeName() function and log statements for Proxy objects being created and destroyed

Author: ryanofsky

include/mp/proxy-io.h

@@ -511,6 +511,7 @@ ProxyClientBase<Interface, Impl>::ProxyClientBase(typename Interface::Client cli
     : m_client(std::move(client)), m_context(connection)
 
 {
+    MP_LOG(*m_context.loop, Log::Debug) << "Creating " << CxxTypeName(*this) << " " << this;
     // Handler for the connection getting destroyed before this client object.
     auto disconnect_cb = m_context.connection->addSyncCleanup([this]() {
         // Release client capability by move-assigning to temporary.
@@ -567,13 +568,16 @@ ProxyClientBase<Interface, Impl>::ProxyClientBase(typename Interface::Client cli
 template <typename Interface, typename Impl>
 ProxyClientBase<Interface, Impl>::~ProxyClientBase() noexcept
 {
+    MP_LOG(*m_context.loop, Log::Debug) << "Cleaning up " << CxxTypeName(*this) << " " << this;
     CleanupRun(m_context.cleanup_fns);
+    MP_LOG(*m_context.loop, Log::Debug) << "Destroying " << CxxTypeName(*this) << " " << this;
 }
 
 template <typename Interface, typename Impl>
 ProxyServerBase<Interface, Impl>::ProxyServerBase(std::shared_ptr<Impl> impl, Connection& connection)
     : m_impl(std::move(impl)), m_context(&connection)
 {
+    MP_LOG(*m_context.loop, Log::Debug) << "Creating " << CxxTypeName(*this) << " " << this;
     assert(m_impl);
 }
 
@@ -592,6 +596,7 @@ ProxyServerBase<Interface, Impl>::ProxyServerBase(std::shared_ptr<Impl> impl, Co
 template <typename Interface, typename Impl>
 ProxyServerBase<Interface, Impl>::~ProxyServerBase()
 {
+    MP_LOG(*m_context.loop, Log::Debug) << "Cleaning up " << CxxTypeName(*this) << " " << this;
     if (m_impl) {
         // If impl is non-null at this point, it means no client is waiting for
         // the m_impl server object to be destroyed synchronously. This can
@@ -618,6 +623,7 @@ ProxyServerBase<Interface, Impl>::~ProxyServerBase()
         });
     }
     assert(m_context.cleanup_fns.empty());
+    MP_LOG(*m_context.loop, Log::Debug) << "Destroying " << CxxTypeName(*this) << " " << this;
 }
 
 //! If the capnp interface defined a special "destroy" method, as described the

include/mp/proxy-types.h

@@ -645,16 +645,16 @@ template <typename Client>
 void clientDestroy(Client& client)
 {
     if (client.m_context.connection) {
-        MP_LOG(*client.m_context.loop, Log::Debug) << "IPC client destroy " << typeid(client).name();
+        MP_LOG(*client.m_context.loop, Log::Debug) << "IPC client destroy " << CxxTypeName(client);
     } else {
-        KJ_LOG(INFO, "IPC interrupted client destroy", typeid(client).name());
+        KJ_LOG(INFO, "IPC interrupted client destroy", CxxTypeName(client));
     }
 }
 
 template <typename Server>
 void serverDestroy(Server& server)
 {
-    MP_LOG(*server.m_context.loop, Log::Debug) << "IPC server destroy " << typeid(server).name();
+    MP_LOG(*server.m_context.loop, Log::Debug) << "IPC server destroy " << CxxTypeName(server);
 }
 
 //! Entry point called by generated client code that looks like:

include/mp/util.h

@@ -7,19 +7,25 @@
 
 #include <capnp/schema.h>
 #include <cassert>
-#include <cstddef>
+#include <cstdlib>
 #include <cstring>
 #include <exception>
 #include <functional>
 #include <kj/string-tree.h>
 #include <mutex>
 #include <string>
 #include <tuple>
+#include <typeinfo>
 #include <type_traits>
 #include <utility>
 #include <variant>
 #include <vector>
 
+#if __has_include(<cxxabi.h>)
+#include <cxxabi.h>
+#include <memory>
+#endif
+
 namespace mp {
 
 //! Generic utility functions used by capnp code.
@@ -274,6 +280,28 @@ inline char* CharCast(unsigned char* c) { return (char*)c; }
 inline const char* CharCast(const char* c) { return c; }
 inline const char* CharCast(const unsigned char* c) { return (const char*)c; }
 
+#if __has_include(<cxxabi.h>)   // GCC & Clang ─ use <cxxabi.h> to demangle
+inline std::string _demangle(const char* m)
+{
+    int status = 0;
+    std::unique_ptr<char, void(*)(void*)> p{
+        abi::__cxa_demangle(m, /*output_buffer=*/nullptr, /*length=*/nullptr, &status), std::free};
+    return (status == 0 && p) ? p.get() : m;   // fall back on mangled if needed
+}
+#else                           // MSVC or other ─ no demangling available
+inline std::string _demangle(const char* m) { return m; }
+#endif
+
+template<class T>
+std::string CxxTypeName(const T& /*unused*/)
+{
+#ifdef __cpp_rtti
+    return _demangle(typeid(std::decay_t<T>).name());
+#else
+    return "<type information unavailable without rtti>";
+#endif
+}
+
 //! Exception thrown from code executing an IPC call that is interrupted.
 struct InterruptException final : std::exception {
     explicit InterruptException(std::string message) : m_message(std::move(message)) {}

src/mp/gen.cpp

@@ -240,8 +240,11 @@ static void Generate(kj::StringPtr src_prefix,
     cpp_types << "// Generated by " PROXY_BIN " from " << src_file << "\n\n";
     cpp_types << "// IWYU pragma: no_include \"mp/proxy.h\"\n";
     cpp_types << "// IWYU pragma: no_include \"mp/proxy-io.h\"\n";
+    cpp_types << "#include <" << include_path << ".h> // IWYU pragma: keep\n";
     cpp_types << "#include <" << include_path << ".proxy.h>\n";
     cpp_types << "#include <" << include_path << ".proxy-types.h> // IWYU pragma: keep\n";
+    cpp_types << "#include <kj/common.h>\n";
+    cpp_types << "#include <mp/util.h>\n";
     cpp_types << "#include <" << PROXY_TYPES << ">\n\n";
     cpp_types << "namespace mp {\n";