refactor: MCP層をmcpc APIベースに刷新

- 独自JSON-RPC処理をmcpcへ置き換え
- 各MCPツールを個別ソースへ分離
- 共通コンテキストと登録処理を整理
- mcpc互換修正と統合テストを更新

1 files changed, 49 insertions, 12 deletions

diff --git a/src/mcp/json.c b/src/mcp/json.c
index dcef91b..62f31c9 100644
--- a/src/mcp/json.c
+++ b/src/mcp/json.c
@@ -4,11 +4,17 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "base/allocator.h"
+
 static bool
 reserve(tiny_json_buffer_t *buffer, size_t addition)
 {
   size_t needed, capacity;
   char *resized;
+  if (buffer == NULL)
+    {
+      return false;
+    }
   if (buffer->failed || addition > SIZE_MAX - buffer->length - 1)
     {
       return false;
@@ -42,11 +48,18 @@ reserve(tiny_json_buffer_t *buffer, size_t addition)
 void
 tiny_json_init(tiny_json_buffer_t *buffer)
 {
-  memset(buffer, 0, sizeof(*buffer));
+  if (buffer != NULL)
+    {
+      memset(buffer, 0, sizeof(*buffer));
+    }
 }
 void
 tiny_json_free(tiny_json_buffer_t *buffer)
 {
+  if (buffer == NULL)
+    {
+      return;
+    }
   free(buffer->data);
   tiny_json_init(buffer);
 }
@@ -54,7 +67,7 @@ tiny_json_free(tiny_json_buffer_t *buffer)
 bool
 tiny_json_raw_n(tiny_json_buffer_t *buffer, const char *value, size_t length)
 {
-  if (!reserve(buffer, length))
+  if ((value == NULL && length != 0) || !reserve(buffer, length))
     {
       return false;
     }
@@ -66,14 +79,14 @@ tiny_json_raw_n(tiny_json_buffer_t *buffer, const char *value, size_t length)
 bool
 tiny_json_raw(tiny_json_buffer_t *buffer, const char *value)
 {
-  return tiny_json_raw_n(buffer, value, strlen(value));
+  return value != NULL && tiny_json_raw_n(buffer, value, strlen(value));
 }
 
 bool
 tiny_json_string(tiny_json_buffer_t *buffer, const char *value)
 {
   const unsigned char *position = (const unsigned char *)value;
-  if (!tiny_json_raw(buffer, "\""))
+  if (value == NULL || !tiny_json_raw(buffer, "\""))
     {
       return false;
     }
@@ -85,36 +98,60 @@ tiny_json_string(tiny_json_buffer_t *buffer, const char *value)
           escaped[0] = '\\';
           escaped[1] = (char)*position;
           escaped[2] = '\0';
-          tiny_json_raw(buffer, escaped);
+          if (!tiny_json_raw(buffer, escaped))
+            {
+              return false;
+            }
         }
       else if (*position == '\b')
         {
-          tiny_json_raw(buffer, "\\b");
+          if (!tiny_json_raw(buffer, "\\b"))
+            {
+              return false;
+            }
         }
       else if (*position == '\f')
         {
-          tiny_json_raw(buffer, "\\f");
+          if (!tiny_json_raw(buffer, "\\f"))
+            {
+              return false;
+            }
         }
       else if (*position == '\n')
         {
-          tiny_json_raw(buffer, "\\n");
+          if (!tiny_json_raw(buffer, "\\n"))
+            {
+              return false;
+            }
         }
       else if (*position == '\r')
         {
-          tiny_json_raw(buffer, "\\r");
+          if (!tiny_json_raw(buffer, "\\r"))
+            {
+              return false;
+            }
         }
       else if (*position == '\t')
         {
-          tiny_json_raw(buffer, "\\t");
+          if (!tiny_json_raw(buffer, "\\t"))
+            {
+              return false;
+            }
         }
       else if (*position < 0x20)
         {
           snprintf(escaped, sizeof(escaped), "\\u%04x", *position);
-          tiny_json_raw(buffer, escaped);
+          if (!tiny_json_raw(buffer, escaped))
+            {
+              return false;
+            }
         }
       else
         {
-          tiny_json_raw_n(buffer, (const char *)position, 1);
+          if (!tiny_json_raw_n(buffer, (const char *)position, 1))
+            {
+              return false;
+            }
         }
       ++position;
     }