add support for OTLP logging/tracing (#599)

- adds `zentelemetry` project which houses new functionality for serializing logs and traces in OpenTelemetry Protocol format (OTLP)
- moved existing stats functionality from `zencore` to `zentelemetry`
- adds `TRefCounted<T>` for vtable-less refcounting
- adds `MemoryArena` class which allows for linear allocation of memory from chunks
- adds `protozero` which is used to encode OTLP protobuf messages

3 files changed, 7 insertions, 2 deletions

diff --git a/src/zenhttp/httpserver.cpp b/src/zenhttp/httpserver.cpp
index 2c063d646..f48c22367 100644
--- a/src/zenhttp/httpserver.cpp
+++ b/src/zenhttp/httpserver.cpp
@@ -86,6 +86,9 @@ MapContentTypeToString(HttpContentType ContentType)
 
 		case HttpContentType::kXML:
 			return "application/xml"sv;
+
+		case HttpContentType::kProtobuf:
+			return "application/x-protobuf"sv;
 	}
 }
 
@@ -119,6 +122,7 @@ static constinit uint32_t HashImagePng					= HashStringDjb2("image/png"sv);
 static constinit uint32_t HashIcon						= HashStringDjb2("ico"sv);
 static constinit uint32_t HashImageIcon					= HashStringDjb2("image/x-icon"sv);
 static constinit uint32_t HashXml						= HashStringDjb2("application/xml"sv);
+static constinit uint32_t HashProtobuf					= HashStringDjb2("application/x-protobuf"sv);
 
 std::once_flag InitContentTypeLookup;
 
@@ -153,6 +157,7 @@ struct HashedTypeEntry
 	{HashIcon,						HttpContentType::kIcon},
 	{HashImageIcon,					HttpContentType::kIcon},
 	{HashXml,						HttpContentType::kXML},
+	{HashProtobuf,					HttpContentType::kProtobuf},
 	// clang-format on
 };
 
diff --git a/src/zenhttp/include/zenhttp/httptest.h b/src/zenhttp/include/zenhttp/httptest.h
index afe71fbce..608462809 100644
--- a/src/zenhttp/include/zenhttp/httptest.h
+++ b/src/zenhttp/include/zenhttp/httptest.h
@@ -3,8 +3,8 @@
 #pragma once
 
 #include <zencore/logging.h>
-#include <zencore/stats.h>
 #include <zenhttp/httpserver.h>
+#include <zentelemetry/stats.h>
 
 #include <atomic>
 #include <unordered_map>
diff --git a/src/zenhttp/xmake.lua b/src/zenhttp/xmake.lua
index b6ffbe467..af4064012 100644
--- a/src/zenhttp/xmake.lua
+++ b/src/zenhttp/xmake.lua
@@ -7,7 +7,7 @@ target('zenhttp')
     add_files("**.cpp")
     add_files("servers/httpsys.cpp", {unity_ignored=true})
     add_includedirs("include", {public=true})
-    add_deps("zencore", "transport-sdk")
+    add_deps("zencore", "zentelemetry", "transport-sdk")
     add_packages(
         "vcpkg::asio",
         "vcpkg::cpr",