fix: MCPCをvendored fork化しMCP準拠と接続安定性を改善

- Git submoduleを廃止してMCPCを直接管理
- Windowsで254リクエスト付近に発生する切断を修正
- JSON-RPC 2.0エラー応答を標準化
- tool schemaとruntimeの必須・任意引数を一致
- 1000回連続呼び出しの回帰テストを追加

1 files changed, 119 insertions, 0 deletions

diff --git a/third_party/mcpc/src/retbuf.c b/third_party/mcpc/src/retbuf.c
new file mode 100644
index 0000000..0429f15
--- /dev/null
+++ b/third_party/mcpc/src/retbuf.c
@@ -0,0 +1,119 @@
+// This file is part of the mcpc library.
+//
+// Copyright (C) 2025 Michael Lee <micl2e2 AT proton.me>
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of
+// this software and associated documentation files (the "Software"), to deal in
+// the Software without restriction, including without limitation the rights to
+// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+// the Software, and to permit persons to whom the Software is furnished to do so,
+// subject to the following conditions: 
+// 
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software. 
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+#include "retbuf.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "mjson.h"
+
+retbuf_t
+retbuf_new (size_t cap, size_t *len)
+{
+  retbuf_t x = {
+    .cap = cap,.buf0 = malloc (cap),.len = len
+  };
+  return x;
+}
+
+void
+retbuf_free (retbuf_t rtbf)
+{
+  free (rtbf.buf0);
+}
+
+uint8_t
+rtbuf_printf_adv (retbuf_t rtbf, size_t advl, const char8_t *u8str, ...)
+{
+  va_list args;
+  int printed;
+  size_t remaining;
+  (void) advl;
+  if (rtbf.buf0 == nullptr || rtbf.len == nullptr || *rtbf.len >= rtbf.cap)
+    return 1;
+  va_start (args, u8str);
+  remaining = rtbf.cap - *rtbf.len;
+  printed = vsnprintf (rtbf.buf0 + *rtbf.len, remaining, (const char *) u8str, args);
+  va_end (args);
+  if (printed < 0 || (size_t) printed >= remaining)
+    {
+      *rtbf.len = rtbf.cap;
+      return 1;
+    }
+  *rtbf.len += (size_t) printed;
+  return 0;
+}
+
+uint8_t
+rtbuf_printf (retbuf_t rtbf, const char8_t *u8str, ...)
+{
+  va_list args;
+  int printed;
+  size_t remaining;
+  if (rtbf.buf0 == nullptr || rtbf.len == nullptr || *rtbf.len >= rtbf.cap)
+    return 1;
+  va_start (args, u8str);
+  remaining = rtbf.cap - *rtbf.len;
+  printed = vsnprintf (rtbf.buf0 + *rtbf.len, remaining, (const char *) u8str, args);
+  va_end (args);
+  if (printed < 0 || (size_t) printed >= remaining)
+    {
+      *rtbf.len = rtbf.cap;
+      return 1;
+    }
+  *rtbf.len += (size_t) printed;
+  return 0;
+}
+
+uint8_t
+rtbuf_printf_mjfmt (retbuf_t rtbf, const char8_t *fmt8, ...)
+{
+  va_list args;
+  va_start (args, fmt8);
+
+  const char *fmt = (const char *) fmt8;
+  struct mjson_fixedbuf fb = { rtbf.buf0, (int)rtbf.cap, (int)*rtbf.len };
+  int advl = mjson_vprintf (&mjson_print_fixed_buf, &fb, fmt, &args);
+
+  if (advl < 0 || (size_t) advl > rtbf.cap - *rtbf.len)
+    *rtbf.len = rtbf.cap;
+  else
+    *rtbf.len += (size_t) advl;
+
+  va_end (args);
+  return 0;
+}
+
+// TODO change _printf_ use this one
+u8_t
+rtbuf_vprintf_mjfmt (retbuf_t rtbf, const char8_t *fmt8, va_list *vargs)
+{
+  const char *fmt = (const char *) fmt8;
+  struct mjson_fixedbuf fb = { rtbf.buf0, (int)rtbf.cap, (int)*rtbf.len };
+  int advl = mjson_vprintf (&mjson_print_fixed_buf, &fb, fmt, vargs);	// TODO: __va_list_tag (*)[1]’
+  if (advl < 0 || (size_t) advl > rtbf.cap - *rtbf.len)
+    *rtbf.len = rtbf.cap;
+  else
+    *rtbf.len += (size_t) advl;
+  return 0;
+}