From d386bc8c91ec655e243c2e387fcaedf39ef7c7f4 Mon Sep 17 00:00:00 2001
From: Gary Talent <gary@drinkingtea.net>
Date: Mon, 13 Nov 2023 23:42:09 -0600
Subject: [PATCH] [ox/mc] Fix MC read alloca in a loop

---
 deps/ox/src/ox/mc/read.cpp  |  8 ++++++++
 deps/ox/src/ox/mc/read.hpp  |  2 ++
 deps/ox/src/ox/mc/write.hpp | 14 +++++++++-----
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/deps/ox/src/ox/mc/read.cpp b/deps/ox/src/ox/mc/read.cpp
index 303087c8..d52b3755 100644
--- a/deps/ox/src/ox/mc/read.cpp
+++ b/deps/ox/src/ox/mc/read.cpp
@@ -6,6 +6,14 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
+#include <ox/model/modelhandleradaptor.hpp>
+#include <ox/std/buffer.hpp>
+#include <ox/std/reader.hpp>
+
+#include "read.hpp"
+
 namespace ox {
 
+template class ModelHandlerInterface<MetalClawReaderTemplate<BufferReader>>;
+
 }
diff --git a/deps/ox/src/ox/mc/read.hpp b/deps/ox/src/ox/mc/read.hpp
index 8e38a824..f6252e7a 100644
--- a/deps/ox/src/ox/mc/read.hpp
+++ b/deps/ox/src/ox/mc/read.hpp
@@ -549,4 +549,6 @@ Result<T> readMC(const Buffer &buff) noexcept {
 	return readMC<T>(buff.data(), buff.size());
 }
 
+extern template class ModelHandlerInterface<MetalClawReaderTemplate<BufferReader>>;
+
 }
diff --git a/deps/ox/src/ox/mc/write.hpp b/deps/ox/src/ox/mc/write.hpp
index edb7a568..f5a6d51b 100644
--- a/deps/ox/src/ox/mc/write.hpp
+++ b/deps/ox/src/ox/mc/write.hpp
@@ -359,15 +359,19 @@ constexpr Error MetalClawWriter<Writer>::field(const char*, const HashMap<String
 		ModelHandlerInterface handler{&writer};
 		// double len for both key and value
 		oxReturnError(handler.setTypeInfo("Map", 0, {}, len * 2));
-		// write the array
-		for (std::size_t i = 0; i < len; i++) {
-			const auto &key = keys[i];
+		// this loop body needs to be in a lambda because of the potential alloca call
+		constexpr auto loopBody = [](auto &handler, auto const&key, auto const&val) -> ox::Error {
 			const auto keyLen = ox_strlen(key);
 			auto wkey = ox_malloca(keyLen + 1, char, 0);
 			memcpy(wkey, key.c_str(), keyLen + 1);
 			oxReturnError(handler.fieldCString("", wkey.get(), keyLen));
-			oxRequireM(value, val->at(key));
-			oxReturnError(handler.field("", value));
+			oxRequireM(value, val.at(key));
+			return handler.field("", value);
+		};
+		// write the array
+		for (std::size_t i = 0; i < len; i++) {
+			auto const&key = keys[i];
+			oxReturnError(loopBody(handler, key, *val));
 		}
 		oxReturnError(writer.finalize());
 		fieldSet = true;