[lldb/Lua] Recognize "quit" as a way to exit the interactive script interpreter.

[JDevlieghere]

Summary

Add a way to quit the interactive script interpreter from a shell tests. Currently, the only way (that I know) to exit the interactive Lua interpreter is to send a EOF with CTRL-D. I noticed that the embedded Python script interpreter accepts quit (while the regular python interpreter doesn't). I've added a special case to the Lua interpreter to do the same.

[labath]

It seems reasonable. Btw, have you figured out how the embedded python does it? -- I haven't been able to find the code for handling that.

The python interpreter also intercepts os.exit() to avoid terminating the program (it just terminates the python session). I suppose we should do the same with lua's os.exit...

[JDevlieghere]

In D82272#2106402, @labath wrote:

It seems reasonable. Btw, have you figured out how the embedded python does it? -- I haven't been able to find the code for handling that.

No, I couldn't find the code either.

The python interpreter also intercepts os.exit() to avoid terminating the program (it just terminates the python session). I suppose we should do the same with lua's os.exit...

Yep, that sounds good.

lldb/source/Plugins/ScriptInterpreter/Lua/ScriptInterpreterLua.cpp

public:
   }
 
   ~IOHandlerLuaInterpreter() override {
     llvm::cantFail(m_script_interpreter.LeaveSession());
   }
 
   void IOHandlerInputComplete(IOHandler &io_handler,
                               std::string &data) override {
+    if (llvm::StringRef(data).rtrim() == "quit") {
+      io_handler.SetIsDone(true);
+      return;
+    }
+
     if (llvm::Error error = m_script_interpreter.GetLua().Run(data)) {
       *GetOutputStreamFileSP() << llvm::toString(std::move(error));
     }
   }
 
 private:
   ScriptInterpreterLua &m_script_interpreter;
 };

lldb/test/Shell/ScriptInterpreter/Lua/quit.test

+# REQUIRES: lua
+# UNSUPPORTED: lldb-repro
+#
+# RUN: cat %s | %lldb --script-language lua 2>&1 | FileCheck %s
+script
+print(95000 + 126)
+quit
+target list
+# CHECK: 95126
+# CHECK: No targets