From b204981acaceccb88a7c568fa76c3bd1d62c8d49 Mon Sep 17 00:00:00 2001
From: Jay Kruer <j@dank.systems>
Date: Tue, 2 Aug 2022 09:32:22 -0700
Subject: [PATCH] Add Ctrl-C handling to the REPL (#537)

Co-authored-by: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
---
 CLI/Repl.cpp | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/CLI/Repl.cpp b/CLI/Repl.cpp
index 4136073..13033bb 100644
--- a/CLI/Repl.cpp
+++ b/CLI/Repl.cpp
@@ -20,6 +20,9 @@
 #ifdef _WIN32
 #include <io.h>
 #include <fcntl.h>
+
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
 #endif
 
 #ifdef CALLGRIND
@@ -27,6 +30,7 @@
 #endif
 
 #include <locale.h>
+#include <signal.h>
 
 LUAU_FASTFLAG(DebugLuauTimeTracing)
 
@@ -47,6 +51,35 @@ enum class CompileFormat
 
 constexpr int MaxTraversalLimit = 50;
 
+// Ctrl-C handling
+static void sigintCallback(lua_State* L, int gc)
+{
+    if (gc >= 0)
+        return;
+
+    lua_callbacks(L)->interrupt = NULL;
+
+    lua_rawcheckstack(L, 1); // reserve space for error string
+    luaL_error(L, "Execution interrupted");
+}
+
+static lua_State* replState = NULL;
+
+#ifdef _WIN32
+BOOL WINAPI sigintHandler(DWORD signal)
+{
+    if (signal == CTRL_C_EVENT && replState)
+        lua_callbacks(replState)->interrupt = &sigintCallback;
+    return TRUE;
+}
+#else
+static void sigintHandler(int signum)
+{
+    if (signum == SIGINT && replState)
+        lua_callbacks(replState)->interrupt = &sigintCallback;
+}
+#endif
+
 struct GlobalOptions
 {
     int optimizationLevel = 1;
@@ -535,6 +568,15 @@ static void runRepl()
     lua_State* L = globalState.get();
 
     setupState(L);
+
+    // setup Ctrl+C handling
+    replState = L;
+#ifdef _WIN32
+    SetConsoleCtrlHandler(sigintHandler, TRUE);
+#else
+    signal(SIGINT, sigintHandler);
+#endif
+
     luaL_sandboxthread(L);
     runReplImpl(L);
 }