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diff --git a/indra/newview/llluamanager.cpp b/indra/newview/llluamanager.cpp
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+/**
+ * @file llluamanager.cpp
+ * @brief classes and functions for interfacing with LUA.
+ *
+ * $LicenseInfo:firstyear=2023&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2023, Linden Research, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
+ * $/LicenseInfo$
+ *
+ */
+
+#include "llviewerprecompiledheaders.h"
+#include "llluamanager.h"
+
+#include "hexdump.h"
+#include "llerror.h"
+#include "lleventcoro.h"
+#include "lleventfilter.h"
+#include "llevents.h"
+#include "llinstancetracker.h"
+#include "llleaplistener.h"
+#include "lluuid.h"
+#include "stringize.h"
+
+// skip all these link dependencies for integration testing
+#ifndef LL_TEST
+#include "lluilistener.h"
+#include "llviewercontrol.h"
+
+// FIXME extremely hacky way to get to the UI Listener framework. There's
+// a cleaner way.
+extern LLUIListener sUIListener;
+#endif // ! LL_TEST
+
+#include <boost/algorithm/string/replace.hpp>
+
+#include "luau/luacode.h"
+#include "luau/lua.h"
+#include "luau/luaconf.h"
+#include "luau/lualib.h"
+
+#define lua_register(L, n, f) (lua_pushcfunction(L, (f), n), lua_setglobal(L, (n)))
+#define lua_rawlen lua_objlen
+
+#include <algorithm>
+#include <cstdlib> // std::rand()
+#include <cstring> // std::memcpy()
+#include <map>
+#include <memory> // std::unique_ptr
+#include <sstream>
+#include <string_view>
+#include <vector>
+
+std::string lua_tostdstring(lua_State* L, int index);
+void lua_pushstdstring(lua_State* L, const std::string& str);
+LLSD lua_tollsd(lua_State* L, int index);
+void lua_pushllsd(lua_State* L, const LLSD& data);
+
+/**
+ * LuaListener is based on LLLeap. It serves an analogous function.
+ *
+ * Each LuaListener instance has an int key, generated randomly to
+ * inconvenience malicious Lua scripts wanting to mess with others. The idea
+ * is that a given lua_State stores in its Registry:
+ * - "event.listener": the int key of the corresponding LuaListener, if any
+ * - "event.function": the Lua function to be called with incoming events
+ * The original thought was that LuaListener would itself store the Lua
+ * function -- but surprisingly, there is no C/C++ type in the API that stores
+ * a Lua function.
+ *
+ * (We considered storing in "event.listener" the LuaListener pointer itself
+ * as a light userdata, but the problem would be if Lua code overwrote that.
+ * We want to prevent any Lua script from crashing the viewer, intentionally
+ * or otherwise. Safer to use a key lookup.)
+ *
+ * Like LLLeap, each LuaListener instance also has an associated
+ * LLLeapListener to respond to LLEventPump management commands.
+ */
+class LuaListener: public LLInstanceTracker<LuaListener, int>
+{
+ using super = LLInstanceTracker<LuaListener, int>;
+public:
+ LuaListener(lua_State* L):
+ super(getUniqueKey()),
+ mListener(
+ new LLLeapListener(
+ [L](LLEventPump& pump, const std::string& listener)
+ { return connect(L, pump, listener); }))
+ {
+ mReplyConnection = connect(L, mReplyPump, "LuaListener");
+ }
+
+ LuaListener(const LuaListener&) = delete;
+ LuaListener& operator=(const LuaListener&) = delete;
+
+ ~LuaListener()
+ {
+ LL_DEBUGS("Lua") << "~LuaListener('" << mReplyPump.getName() << "')" << LL_ENDL;
+ }
+
+ std::string getReplyName() const { return mReplyPump.getName(); }
+ std::string getCommandName() const { return mListener->getPumpName(); }
+
+private:
+ static int getUniqueKey()
+ {
+ // Find a random key that does NOT already correspond to a LuaListener
+ // instance. Passing a duplicate key to LLInstanceTracker would do Bad
+ // Things.
+ int key;
+ do
+ {
+ key = std::rand();
+ } while (LuaListener::getInstance(key));
+ // This is theoretically racy, if we were instantiating new
+ // LuaListeners on multiple threads. Don't.
+ return key;
+ }
+
+ static LLBoundListener connect(lua_State* L, LLEventPump& pump, const std::string& listener)
+ {
+ return pump.listen(
+ listener,
+ [L, pumpname=pump.getName()](const LLSD& data)
+ { return call_lua(L, pumpname, data); });
+ }
+
+ static bool call_lua(lua_State* L, const std::string& pump, const LLSD& data)
+ {
+ LL_INFOS("Lua") << "LuaListener::call_lua('" << pump << "', " << data << ")" << LL_ENDL;
+ if (! lua_checkstack(L, 3))
+ {
+ LL_WARNS("Lua") << "Cannot extend Lua stack to call listen_events() callback"
+ << LL_ENDL;
+ return false;
+ }
+ // push the registered Lua callback function stored in our registry as
+ // "event.function"
+ lua_getfield(L, LUA_REGISTRYINDEX, "event.function");
+ llassert(lua_isfunction(L, -1));
+ // pass pump name
+ lua_pushstdstring(L, pump);
+ // then the data blob
+ lua_pushllsd(L, data);
+ // call the registered Lua listener function; allow it to return bool;
+ // no message handler
+ auto status = lua_pcall(L, 2, 1, 0);
+ bool result{ false };
+ if (status != LUA_OK)
+ {
+ LL_WARNS("Lua") << "Error in listen_events() callback: "
+ << lua_tostdstring(L, -1) << LL_ENDL;
+ }
+ else
+ {
+ result = lua_toboolean(L, -1);
+ }
+ // discard either the error message or the bool return value
+ lua_pop(L, 1);
+ return result;
+ }
+
+#ifndef LL_TEST
+ LLEventStream mReplyPump{ LLUUID::generateNewID().asString() };
+#else
+ LLEventLogProxyFor<LLEventStream> mReplyPump{ "luapump", false };
+#endif
+ LLTempBoundListener mReplyConnection;
+ std::unique_ptr<LLLeapListener> mListener;
+};
+
+/**
+ * LuaPopper is an RAII struct whose role is to pop some number of entries
+ * from the Lua stack if the calling function exits early.
+ */
+struct LuaPopper
+{
+ LuaPopper(lua_State* L, int count):
+ mState(L),
+ mCount(count)
+ {}
+
+ LuaPopper(const LuaPopper&) = delete;
+ LuaPopper& operator=(const LuaPopper&) = delete;
+
+ ~LuaPopper()
+ {
+ if (mCount)
+ {
+ lua_pop(mState, mCount);
+ }
+ }
+
+ void disarm() { set(0); }
+ void set(int count) { mCount = count; }
+
+ lua_State* mState;
+ int mCount;
+};
+
+/**
+ * LuaFunction is a base class containing a static registry of its static
+ * subclass call() methods. call() is NOT virtual: instead, each subclass
+ * constructor passes a pointer to its distinct call() method to the base-
+ * class constructor, along with a name by which to register that method.
+ *
+ * The init() method walks the registry and registers each such name with the
+ * passed lua_State.
+ */
+class LuaFunction
+{
+public:
+ LuaFunction(const std::string_view& name, lua_CFunction function)
+ {
+ getRegistry().emplace(name, function);
+ }
+
+ static void init(lua_State* L)
+ {
+ for (const auto& pair: getRegistry())
+ {
+ lua_register(L, pair.first.c_str(), pair.second);
+ }
+ }
+
+ static lua_CFunction get(const std::string& key)
+ {
+ // use find() instead of subscripting to avoid creating an entry for
+ // unknown key
+ const auto& registry{ getRegistry() };
+ auto found{ registry.find(key) };
+ return (found == registry.end())? nullptr : found->second;
+ }
+
+private:
+ using Registry = std::map<std::string, lua_CFunction>;
+ static Registry& getRegistry()
+ {
+ // use a function-local static to ensure it's initialized
+ static Registry registry;
+ return registry;
+ }
+};
+
+/**
+ * lua_function(name) is a macro to facilitate defining C++ functions
+ * available to Lua. It defines a subclass of LuaFunction and declares a
+ * static instance of that subclass, thereby forcing the compiler to call its
+ * constructor at module initialization time. The constructor passes the
+ * stringized instance name to its LuaFunction base-class constructor, along
+ * with a pointer to the static subclass call() method. It then emits the
+ * call() method definition header, to be followed by a method body enclosed
+ * in curly braces as usual.
+ */
+#define lua_function(name) \
+static struct name##_ : public LuaFunction \
+{ \
+ name##_(): LuaFunction(#name, &call) {} \
+ static int call(lua_State* L); \
+} name; \
+int name##_::call(lua_State* L)
+// {
+// ... supply method body here, referencing 'L' ...
+// }
+
+/*
+// This function consumes ALL Lua stack arguments and returns concatenated
+// message string
+std::string lua_print_msg_args(lua_State* L, const std::string_view& level)
+{
+ // On top of existing Lua arguments, push 'where' info
+ luaL_checkstack(L, 1, nullptr);
+ luaL_where(L, 1);
+ // start with the 'where' info at the top of the stack
+ std::ostringstream out;
+ out << lua_tostring(L, -1);
+ lua_pop(L, 1);
+ const char* sep = ""; // 'where' info ends with ": "
+ // now iterate over arbitrary args, calling Lua tostring() on each and
+ // concatenating with separators
+ for (int p = 1; p <= lua_gettop(L); ++p)
+ {
+ out << sep;
+ sep = " ";
+ // push Lua tostring() function -- note, semantically different from
+ // lua_tostring()!
+ lua_getglobal(L, "tostring");
+ // Now the stack is arguments 1 .. N, plus tostring().
+ // Rotate downwards, producing stack args 2 .. N, tostring(), arg1.
+ lua_rotate(L, 1, -1);
+ // pop tostring() and arg1, pushing tostring(arg1)
+ // (ignore potential error code from lua_pcall() because, if there was
+ // an error, we expect the stack top to be an error message -- which
+ // we'll print)
+ lua_pcall(L, 1, 1, 0);
+ // stack now holds args 2 .. N, tostring(arg1)
+ out << lua_tostring(L, -1);
+ }
+ // pop everything
+ lua_settop(L, 0);
+ // capture message string
+ std::string msg{ out.str() };
+ // put message out there for any interested party (*koff* LLFloaterLUADebug *koff*)
+ LLEventPumps::instance().obtain("lua output").post(stringize(level, ": ", msg));
+ return msg;
+}
+*/
+
+std::string lua_print_msg(lua_State *L, const std::string_view &level)
+{
+ lua_getglobal(L, "tostring");
+
+ lua_pushvalue(L, -1); /* function to be called */
+ lua_pushvalue(L, 1); /* value to print */
+ lua_call(L, 1, 1);
+ std::string msg = lua_tostring(L, -1);
+
+ LLEventPumps::instance().obtain("lua output").post(stringize(level, ": ", msg));
+ return msg;
+}
+
+lua_function(print_debug)
+{
+ LL_DEBUGS("Lua") << lua_print_msg(L, "DEBUG") << LL_ENDL;
+ return 0;
+}
+
+// also used for print(); see LuaState constructor
+lua_function(print_info)
+{
+ LL_INFOS("Lua") << lua_print_msg(L, "INFO") << LL_ENDL;
+ return 0;
+}
+
+lua_function(print_warning)
+{
+ LL_WARNS("Lua") << lua_print_msg(L, "WARN") << LL_ENDL;
+ return 0;
+}
+
+#ifndef LL_TEST
+
+lua_function(run_ui_command)
+{
+ int top = lua_gettop(L);
+ std::string func_name;
+ if (top >= 1)
+ {
+ func_name = lua_tostring(L,1);
+ }
+ std::string parameter;
+ if (top >= 2)
+ {
+ parameter = lua_tostring(L,2);
+ }
+ LL_WARNS("LUA") << "running ui func " << func_name << " parameter " << parameter << LL_ENDL;
+ LLSD event;
+ event["function"] = func_name;
+ if (!parameter.empty())
+ {
+ event["parameter"] = parameter;
+ }
+ sUIListener.call(event);
+
+ lua_settop(L, 0);
+ return 0;
+}
+#endif // ! LL_TEST
+
+lua_function(post_on)
+{
+ std::string pumpname{ lua_tostdstring(L, 1) };
+ LLSD data{ lua_tollsd(L, 2) };
+ lua_pop(L, 2);
+ LL_INFOS("Lua") << "post_on('" << pumpname << "', " << data << ")" << LL_ENDL;
+ LLEventPumps::instance().obtain(pumpname).post(data);
+ return 0;
+}
+
+lua_function(listen_events)
+{
+ if (! lua_isfunction(L, 1))
+ {
+ luaL_typeerror(L, 1, "function");
+ return 0;
+ }
+ luaL_checkstack(L, 2, nullptr);
+
+ // Get the lua_State* for the main thread of this state, in case we were
+ // called from a coroutine thread. We're going to make callbacks into Lua
+ // code, and we want to do it on the main thread rather than a (possibly
+ // suspended) coroutine thread.
+ // Registry table is at pseudo-index LUA_REGISTRYINDEX
+ // Main thread is at registry key LUA_RIDX_MAINTHREAD
+ auto regtype {lua_rawgeti(L, LUA_REGISTRYINDEX, 1 /*LUA_RIDX_MAINTHREAD*/)};
+ // Not finding the main thread at the documented place isn't a user error,
+ // it's a Problem
+ llassert_always(regtype == LUA_TTHREAD);
+ lua_State* mainthread{ lua_tothread(L, -1) };
+ // pop the main thread
+ lua_pop(L, 1);
+
+ luaL_checkstack(mainthread, 1, nullptr);
+ LuaListener::ptr_t listener;
+ // Does the main thread already have a LuaListener stored in the registry?
+ // That is, has this Lua chunk already called listen_events()?
+ auto keytype{ lua_getfield(mainthread, LUA_REGISTRYINDEX, "event.listener") };
+ llassert(keytype == LUA_TNIL || keytype == LUA_TNUMBER);
+ if (keytype == LUA_TNUMBER)
+ {
+ // We do already have a LuaListener. Retrieve it.
+ int isint;
+ listener = LuaListener::getInstance(lua_tointegerx(mainthread, -1, &isint));
+ // pop the int "event.listener" key
+ lua_pop(mainthread, 1);
+ // Nobody should have destroyed this LuaListener instance!
+ llassert(isint && listener);
+ }
+ else
+ {
+ // pop the nil "event.listener" key
+ lua_pop(mainthread, 1);
+ // instantiate a new LuaListener, binding the mainthread state -- but
+ // use a no-op deleter: we do NOT want to delete this new LuaListener
+ // on return from listen_events()!
+ listener.reset(new LuaListener(mainthread), [](LuaListener*){});
+ // set its key in the field where we'll look for it later
+ lua_pushinteger(mainthread, listener->getKey());
+ lua_setfield(mainthread, LUA_REGISTRYINDEX, "event.listener");
+ }
+
+ // Now that we've found or created our LuaListener, store the passed Lua
+ // function as the callback. Beware: our caller passed the function on L's
+ // stack, but we want to store it on the mainthread registry.
+ if (L != mainthread)
+ {
+ // push 1 value (the Lua function) from L's stack to mainthread's
+ lua_xmove(L, mainthread, 1);
+ }
+ lua_setfield(mainthread, LUA_REGISTRYINDEX, "event.function");
+
+ // return the reply pump name and the command pump name on caller's lua_State
+ lua_pushstdstring(L, listener->getReplyName());
+ lua_pushstdstring(L, listener->getCommandName());
+ return 2;
+}
+
+lua_function(await_event)
+{
+ // await_event(pumpname [, timeout [, value to return if timeout (default nil)]])
+ auto pumpname{ lua_tostdstring(L, 1) };
+ LLSD result;
+ if (lua_gettop(L) > 1)
+ {
+ auto timeout{ lua_tonumber(L, 2) };
+ // with no 3rd argument, should be LLSD()
+ auto dftval{ lua_tollsd(L, 3) };
+ lua_settop(L, 0);
+ result = llcoro::suspendUntilEventOnWithTimeout(pumpname, timeout, dftval);
+ }
+ else
+ {
+ // no timeout
+ lua_pop(L, 1);
+ result = llcoro::suspendUntilEventOn(pumpname);
+ }
+ lua_pushllsd(L, result);
+ return 1;
+}
+
+/**
+ * RAII class to manage the lifespan of a lua_State
+ */
+class LuaState
+{
+public:
+ LuaState(const std::string_view& desc, LLLUAmanager::script_finished_fn cb):
+ mDesc(desc),
+ mCallback(cb),
+ mState(luaL_newstate())
+ {
+ luaL_openlibs(mState);
+ LuaFunction::init(mState);
+ // Try to make print() write to our log.
+ lua_register(mState, "print", LuaFunction::get("print_info"));
+ }
+
+ LuaState(const LuaState&) = delete;
+ LuaState& operator=(const LuaState&) = delete;
+
+ ~LuaState()
+ {
+ // Did somebody call listen_events() on this LuaState?
+ // That is, is there a LuaListener key in its registry?
+ auto keytype{ lua_getfield(mState, LUA_REGISTRYINDEX, "event.listener") };
+ if (keytype == LUA_TNUMBER)
+ {
+ // We do have a LuaListener. Retrieve it.
+ int isint;
+ auto listener{ LuaListener::getInstance(lua_tointegerx(mState, -1, &isint)) };
+ // pop the int "event.listener" key
+ lua_pop(mState, 1);
+ // if we got a LuaListener instance, destroy it
+ // (if (! isint), lua_tointegerx() returned 0, but key 0 might
+ // validly designate someone ELSE's LuaListener)
+ if (isint && listener)
+ {
+ auto lptr{ listener.get() };
+ listener.reset();
+ delete lptr;
+ }
+ }
+
+ lua_close(mState);
+
+ if (mCallback)
+ {
+ // mError potentially set by previous checkLua() call(s)
+ mCallback(mError);
+ }
+ }
+
+ bool checkLua(int r)
+ {
+ if (r != LUA_OK)
+ {
+ mError = lua_tostring(mState, -1);
+ lua_pop(mState, 1);
+
+ LL_WARNS() << mDesc << ": " << mError << LL_ENDL;
+ return false;
+ }
+ return true;
+ }
+
+ operator lua_State*() const { return mState; }
+
+private:
+ std::string mDesc;
+ LLLUAmanager::script_finished_fn mCallback;
+ lua_State* mState;
+ std::string mError;
+};
+
+void LLLUAmanager::runScriptFile(const std::string& filename, script_finished_fn cb)
+{
+ std::string desc{ stringize("runScriptFile('", filename, "')") };
+ LLCoros::instance().launch(desc, [desc, filename, cb]()
+ {
+ LuaState L(desc, cb);
+
+ auto LUA_sleep_func = [](lua_State *L)
+ {
+ F32 seconds = lua_tonumber(L, -1);
+ lua_pop(L, 1);
+ llcoro::suspendUntilTimeout(seconds);
+ return 0;
+ };
+
+ lua_register(L, "sleep", LUA_sleep_func);
+
+ llifstream in_file;
+ in_file.open(filename.c_str());
+
+ if (in_file.is_open())
+ {
+ std::string text((std::istreambuf_iterator<char>(in_file)), std::istreambuf_iterator<char>());
+
+ size_t bytecodeSize = 0;
+ char *bytecode = luau_compile(text.c_str(), text.length(), NULL, &bytecodeSize);
+ L.checkLua(luau_load(L, desc.c_str(), bytecode, bytecodeSize, 0));
+ free(bytecode);
+
+ L.checkLua(lua_pcall(L, 0, 0, 0));
+
+ in_file.close();
+ }
+ else
+ {
+ LL_WARNS("Lua") << "unable to open script file '" << filename << "'" << LL_ENDL;
+ }
+ });
+}
+
+void LLLUAmanager::runScriptLine(const std::string& cmd, script_finished_fn cb)
+{
+ // find a suitable abbreviation for the cmd string
+ std::string_view shortcmd{ cmd };
+ const size_t shortlen = 40;
+ std::string::size_type eol = shortcmd.find_first_of("\r\n");
+ if (eol != std::string::npos)
+ shortcmd = shortcmd.substr(0, eol);
+ if (shortcmd.length() > shortlen)
+ shortcmd = stringize(shortcmd.substr(0, shortlen), "...");
+
+ std::string desc{ stringize("runScriptLine('", shortcmd, "')") };
+ LLCoros::instance().launch(desc, [desc, cmd, cb]()
+ {
+ LuaState L(desc, cb);
+
+ size_t bytecodeSize = 0;
+ char *bytecode = luau_compile(cmd.c_str(), cmd.length(), NULL, &bytecodeSize);
+ L.checkLua(luau_load(L, desc.c_str(), bytecode, bytecodeSize, 0));
+ free(bytecode);
+ L.checkLua(lua_pcall(L, 0, 0, 0));
+ });
+}
+
+void LLLUAmanager::runScriptOnLogin()
+{
+#ifndef LL_TEST
+ std::string filename = gSavedSettings.getString("AutorunLuaScriptName");
+ if (filename.empty())
+ {
+ LL_INFOS() << "Script name wasn't set." << LL_ENDL;
+ return;
+ }
+
+ filename = gDirUtilp->getExpandedFilename(LL_PATH_USER_SETTINGS, filename);
+ if (!gDirUtilp->fileExists(filename))
+ {
+ LL_INFOS() << filename << " was not found." << LL_ENDL;
+ return;
+ }
+
+ runScriptFile(filename);
+#endif // ! LL_TEST
+}
+
+std::string lua_tostdstring(lua_State* L, int index)
+{
+ size_t len;
+ const char* strval{ lua_tolstring(L, index, &len) };
+ return { strval, len };
+}
+
+void lua_pushstdstring(lua_State* L, const std::string& str)
+{
+ luaL_checkstack(L, 1, nullptr);
+ lua_pushlstring(L, str.c_str(), str.length());
+}
+
+// Usage: std::cout << lua_what(L, stackindex) << ...;
+// Reports on the Lua value found at the passed stackindex.
+// If cast to std::string, returns the corresponding string value.
+class lua_what
+{
+public:
+ lua_what(lua_State* state, int idx):
+ L(state),
+ index(idx)
+ {}
+
+ friend std::ostream& operator<<(std::ostream& out, const lua_what& self)
+ {
+ switch (lua_type(self.L, self.index))
+ {
+ case LUA_TNONE:
+ // distinguish acceptable but non-valid index
+ out << "none";
+ break;
+
+ case LUA_TNIL:
+ out << "nil";
+ break;
+
+ case LUA_TBOOLEAN:
+ {
+ auto oldflags { out.flags() };
+ out << std::boolalpha << lua_toboolean(self.L, self.index);
+ out.flags(oldflags);
+ break;
+ }
+
+ case LUA_TNUMBER:
+ out << lua_tonumber(self.L, self.index);
+ break;
+
+ case LUA_TSTRING:
+ out << std::quoted(lua_tostdstring(self.L, self.index));
+ break;
+
+ case LUA_TUSERDATA:
+ {
+ const S32 maxlen = 20;
+ S32 binlen{ lua_rawlen(self.L, self.index) };
+ LLSD::Binary binary(std::min(maxlen, binlen));
+ std::memcpy(binary.data(), lua_touserdata(self.L, self.index), binary.size());
+ out << LL::hexdump(binary);
+ if (binlen > maxlen)
+ {
+ out << "...(" << (binlen - maxlen) << " more)";
+ }
+ break;
+ }
+
+ case LUA_TLIGHTUSERDATA:
+ out << lua_touserdata(self.L, self.index);
+ break;
+
+ default:
+ // anything else, don't bother trying to report value, just type
+ out << lua_typename(self.L, lua_type(self.L, self.index));
+ break;
+ }
+ return out;
+ }
+
+ operator std::string() const { return stringize(*this); }
+
+private:
+ lua_State* L;
+ int index;
+};
+
+// Usage: std::cout << lua_stack(L) << ...;
+// Reports on the contents of the Lua stack.
+// If cast to std::string, returns the corresponding string value.
+class lua_stack
+{
+public:
+ lua_stack(lua_State* state):
+ L(state)
+ {}
+
+ friend std::ostream& operator<<(std::ostream& out, const lua_stack& self)
+ {
+ const char* sep = "stack: [";
+ for (int index = 1; index <= lua_gettop(self.L); ++index)
+ {
+ out << sep << lua_what(self.L, index);
+ sep = ", ";
+ }
+ out << ']';
+ return out;
+ }
+
+ operator std::string() const { return stringize(*this); }
+
+private:
+ lua_State* L;
+};
+
+// log exit from any block declaring an instance of DebugExit, regardless of
+// how control leaves that block
+struct DebugExit
+{
+ DebugExit(const std::string& name): mName(name) {}
+ DebugExit(const DebugExit&) = delete;
+ DebugExit& operator=(const DebugExit&) = delete;
+ ~DebugExit()
+ {
+ LL_DEBUGS("Lua") << "exit " << mName << LL_ENDL;
+ }
+
+ std::string mName;
+};
+
+// By analogy with existing lua_tomumble() functions, return an LLSD object
+// corresponding to the Lua object at stack index 'index' in state L.
+// This function assumes that a Lua caller is fully aware that they're trying
+// to call a viewer function. In other words, the caller must specifically
+// construct Lua data convertible to LLSD.
+//
+// For proper error handling, we REQUIRE that the Lua runtime be compiled as
+// C++ so errors are raised as C++ exceptions rather than as longjmp() calls:
+// http://www.lua.org/manual/5.4/manual.html#4.4
+// "Internally, Lua uses the C longjmp facility to handle errors. (Lua will
+// use exceptions if you compile it as C++; search for LUAI_THROW in the
+// source code for details.)"
+// Some blocks within this function construct temporary C++ objects in the
+// expectation that these objects will be properly destroyed even if code
+// reached by that block raises a Lua error.
+LLSD lua_tollsd(lua_State* L, int index)
+{
+ LL_DEBUGS("Lua") << "lua_tollsd(" << index << ") of " << lua_gettop(L) << " stack entries: "
+ << lua_what(L, index) << LL_ENDL;
+ DebugExit log_exit("lua_tollsd()");
+ switch (lua_type(L, index))
+ {
+ case LUA_TNONE:
+ // Should LUA_TNONE be an error instead of returning isUndefined()?
+ case LUA_TNIL:
+ return {};
+
+ case LUA_TBOOLEAN:
+ return bool(lua_toboolean(L, index));
+
+ case LUA_TNUMBER:
+ {
+ // check if integer truncation leaves the number intact
+ int isint;
+ lua_Integer intval{ lua_tointegerx(L, index, &isint) };
+ if (isint)
+ {
+ return LLSD::Integer(intval);
+ }
+ else
+ {
+ return lua_tonumber(L, index);
+ }
+ }
+
+ case LUA_TSTRING:
+ return lua_tostdstring(L, index);
+
+ case LUA_TUSERDATA:
+ {
+ LLSD::Binary binary(lua_rawlen(L, index));
+ std::memcpy(binary.data(), lua_touserdata(L, index), binary.size());
+ return binary;
+ }
+
+ case LUA_TTABLE:
+ {
+ // A Lua table correctly constructed to convert to LLSD will have
+ // either consecutive integer keys starting at 1, which we represent
+ // as an LLSD array (with Lua key 1 at C++ index 0), or will have
+ // all string keys.
+ //
+ // In the belief that Lua table traversal skips "holes," that is, it
+ // doesn't report any key/value pair whose value is nil, we allow a
+ // table with integer keys >= 1 but with "holes." This produces an
+ // LLSD array with isUndefined() entries at unspecified keys. There
+ // would be no other way for a Lua caller to construct an
+ // isUndefined() LLSD array entry. However, to guard against crazy int
+ // keys, we forbid gaps larger than a certain size: crazy int keys
+ // could result in a crazy large contiguous LLSD array.
+ //
+ // Possible looseness could include:
+ // - A mix of integer and string keys could produce an LLSD map in
+ // which the integer keys are converted to string. (Key conversion
+ // must be performed in C++, not Lua, to avoid confusing
+ // lua_next().)
+ // - However, since in Lua t[0] and t["0"] are distinct table entries,
+ // do not consider converting numeric string keys to int to return
+ // an LLSD array.
+ // But until we get more experience with actual Lua scripts in
+ // practice, let's say that any deviation is a Lua coding error.
+ // An important property of the strict definition above is that most
+ // conforming data blobs can make a round trip across the language
+ // boundary and still compare equal. A non-conforming data blob would
+ // lose that property.
+ // Known exceptions to round trip identity:
+ // - Empty LLSD map and empty LLSD array convert to empty Lua table.
+ // But empty Lua table converts to isUndefined() LLSD object.
+ // - LLSD::Real with integer value returns as LLSD::Integer.
+ // - LLSD::UUID, LLSD::Date and LLSD::URI all convert to Lua string,
+ // and so return as LLSD::String.
+ // - Lua does not store any table key whose value is nil. An LLSD
+ // array with isUndefined() entries produces a Lua table with
+ // "holes" in the int key sequence; this converts back to an LLSD
+ // array containing corresponding isUndefined() entries -- except
+ // when one or more of the final entries isUndefined(). These are
+ // simply dropped, producing a shorter LLSD array than the original.
+ // - For the same reason, any keys in an LLSD map whose value
+ // isUndefined() are simply discarded in the converted Lua table.
+ // This converts back to an LLSD map lacking those keys.
+ // - If it's important to preserve the original length of an LLSD
+ // array whose final entries are undefined, or the full set of keys
+ // for an LLSD map some of whose values are undefined, store an
+ // LLSD::emptyArray() or emptyMap() instead. These will be
+ // represented in Lua as empty table, which should convert back to
+ // undefined LLSD. Naturally, though, those won't survive a second
+ // round trip.
+
+ // This is the most important of the luaL_checkstack() calls because a
+ // deeply nested Lua structure will enter this case at each level, and
+ // we'll need another 2 stack slots to traverse each nested table.
+ luaL_checkstack(L, 2, nullptr);
+ // BEFORE we push nil to initialize the lua_next() traversal, convert
+ // 'index' to absolute! Our caller might have passed a relative index;
+ // we do, below: lua_tollsd(L, -1). If 'index' is -1, then when we
+ // push nil, what we find at index -1 is nil, not the table!
+ index = lua_absindex(L, index);
+ LL_DEBUGS("Lua") << "checking for empty table" << LL_ENDL;
+ lua_pushnil(L); // first key
+ LL_DEBUGS("Lua") << lua_stack(L) << LL_ENDL;
+ if (! lua_next(L, index))
+ {
+ // it's a table, but the table is empty -- no idea if it should be
+ // modeled as empty array or empty map -- return isUndefined(),
+ // which can be consumed as either
+ LL_DEBUGS("Lua") << "empty table" << LL_ENDL;
+ return {};
+ }
+ // key is at stack index -2, value at index -1
+ // from here until lua_next() returns 0, have to lua_pop(2) if we
+ // return early
+ LuaPopper popper(L, 2);
+ // Remember the type of the first key
+ auto firstkeytype{ lua_type(L, -2) };
+ LL_DEBUGS("Lua") << "table not empty, first key type " << lua_typename(L, firstkeytype)
+ << LL_ENDL;
+ switch (firstkeytype)
+ {
+ case LUA_TNUMBER:
+ {
+ // First Lua key is a number: try to convert table to LLSD array.
+ // This is tricky because we don't know in advance the size of the
+ // array. The Lua reference manual says that lua_rawlen() is the
+ // same as the length operator '#'; but the length operator states
+ // that it might stop at any "hole" in the subject table.
+ // Moreover, the Lua next() function (and presumably lua_next())
+ // traverses a table in unspecified order, even for numeric keys
+ // (emphasized in the doc).
+ // Make a preliminary pass over the whole table to validate and to
+ // collect keys.
+ std::vector<LLSD::Integer> keys;
+ // Try to determine the length of the table. If the length
+ // operator is truthful, avoid allocations while we grow the keys
+ // vector. Even if it's not, we can still grow the vector, albeit
+ // a little less efficiently.
+ keys.reserve(lua_objlen(L, index));
+ do
+ {
+ auto arraykeytype{ lua_type(L, -2) };
+ switch (arraykeytype)
+ {
+ case LUA_TNUMBER:
+ {
+ int isint;
+ lua_Integer intkey{ lua_tointegerx(L, -2, &isint) };
+ if (! isint)
+ {
+ // key isn't an integer - this doesn't fit our LLSD
+ // array constraints
+ luaL_error(L, "Expected integer array key, got %f instead", lua_tonumber(L, -2));
+ return 0;
+ }
+ if (intkey < 1)
+ {
+ luaL_error(L, "array key %d out of bounds", int(intkey));
+ return 0;
+ }
+
+ keys.push_back(LLSD::Integer(intkey));
+ break;
+ }
+
+ case LUA_TSTRING:
+ // break out strings specially to report the value
+ luaL_error(L, "Cannot convert string array key '%s' to LLSD", lua_tostring(L, -2));
+ return 0;
+
+ default:
+ luaL_error(L, "Cannot convert %s array key to LLSD", lua_typename(L, arraykeytype));
+ return 0;
+ }
+
+ // remove value, keep key for next iteration
+ lua_pop(L, 1);
+ } while (lua_next(L, index) != 0);
+ popper.disarm();
+ // Table keys are all integers: are they reasonable integers?
+ // Arbitrary max: may bite us, but more likely to protect us
+ size_t array_max{ 10000 };
+ if (keys.size() > array_max)
+ {
+ luaL_error(L, "Conversion from Lua to LLSD array limited to %d entries", int(array_max));
+ return 0;
+ }
+ // We know the smallest key is >= 1. Check the largest. We also
+ // know the vector is NOT empty, else we wouldn't have gotten here.
+ std::sort(keys.begin(), keys.end());
+ LLSD::Integer highkey = *keys.rbegin();
+ if ((highkey - LLSD::Integer(keys.size())) > 100)
+ {
+ // Looks like we've gone beyond intentional array gaps into
+ // crazy key territory.
+ luaL_error(L, "Gaps in Lua table too large for conversion to LLSD array");
+ return 0;
+ }
+ LL_DEBUGS("Lua") << "collected " << keys.size() << " keys, max " << highkey << LL_ENDL;
+ // right away expand the result array to the size we'll need
+ LLSD result{ LLSD::emptyArray() };
+ result[highkey - 1] = LLSD();
+ // Traverse the table again, and this time populate result array.
+ lua_pushnil(L); // first key
+ while (lua_next(L, index))
+ {
+ // key at stack index -2, value at index -1
+ // We've already validated lua_tointegerx() for each key.
+ auto key{ lua_tointeger(L, -2) };
+ LL_DEBUGS("Lua") << "key " << key << ':' << LL_ENDL;
+ // Don't forget to subtract 1 from Lua key for LLSD subscript!
+ result[LLSD::Integer(key) - 1] = lua_tollsd(L, -1);
+ // remove value, keep key for next iteration
+ lua_pop(L, 1);
+ }
+ return result;
+ }
+
+ case LUA_TSTRING:
+ {
+ // First Lua key is a string: try to convert table to LLSD map
+ LLSD result{ LLSD::emptyMap() };
+ do
+ {
+ auto mapkeytype{ lua_type(L, -2) };
+ if (mapkeytype != LUA_TSTRING)
+ {
+ luaL_error(L, "Cannot convert %s map key to LLSD", lua_typename(L, mapkeytype));
+ return 0;
+ }
+
+ auto key{ lua_tostdstring(L, -2) };
+ LL_DEBUGS("Lua") << "map key " << std::quoted(key) << ':' << LL_ENDL;
+ result[key] = lua_tollsd(L, -1);
+ // remove value, keep key for next iteration
+ lua_pop(L, 1);
+ } while (lua_next(L, index) != 0);
+ popper.disarm();
+ return result;
+ }
+
+ default:
+ // First Lua key isn't number or string: sorry
+ luaL_error(L, "Cannot convert %s table key to LLSD", lua_typename(L, firstkeytype));
+ return 0;
+ }
+ }
+
+ default:
+ // Other Lua entities (e.g. function, C function, light userdata,
+ // thread, userdata) are not convertible to LLSD, indicating a coding
+ // error in the caller.
+ luaL_error(L, "Cannot convert type %s to LLSD", luaL_typename(L, index));
+ return 0;
+ }
+}
+
+// By analogy with existing lua_pushmumble() functions, push onto state L's
+// stack a Lua object corresponding to the passed LLSD object.
+void lua_pushllsd(lua_State* L, const LLSD& data)
+{
+ // might need 2 slots for array or map
+ luaL_checkstack(L, 2, nullptr);
+ switch (data.type())
+ {
+ case LLSD::TypeUndefined:
+ lua_pushnil(L);
+ break;
+
+ case LLSD::TypeBoolean:
+ lua_pushboolean(L, data.asBoolean());
+ break;
+
+ case LLSD::TypeInteger:
+ lua_pushinteger(L, data.asInteger());
+ break;
+
+ case LLSD::TypeReal:
+ lua_pushnumber(L, data.asReal());
+ break;
+
+ case LLSD::TypeBinary:
+ {
+ auto binary{ data.asBinary() };
+ std::memcpy(lua_newuserdata(L, binary.size()),
+ binary.data(), binary.size());
+ break;
+ }
+
+ case LLSD::TypeMap:
+ {
+ // push a new table with space for our non-array keys
+ lua_createtable(L, 0, data.size());
+ for (const auto& pair: llsd::inMap(data))
+ {
+ // push value -- so now table is at -2, value at -1
+ lua_pushllsd(L, pair.second);
+ // pop value, assign to table[key]
+ lua_setfield(L, -2, pair.first.c_str());
+ }
+ break;
+ }
+
+ case LLSD::TypeArray:
+ {
+ // push a new table with space for array entries
+ lua_createtable(L, data.size(), 0);
+ lua_Integer key{ 0 };
+ for (const auto& item: llsd::inArray(data))
+ {
+ // push new array value: table at -2, value at -1
+ lua_pushllsd(L, item);
+ // pop value, assign table[key] = value
+ lua_rawseti(L, -2, ++key);
+ }
+ break;
+ }
+
+ case LLSD::TypeString:
+ case LLSD::TypeUUID:
+ case LLSD::TypeDate:
+ case LLSD::TypeURI:
+ default:
+ {
+ lua_pushstdstring(L, data.asString());
+ break;
+ }
+ }
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-01-07 16:39:52 +0000