Interpreter.cc

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#include "Interpreter.hh"
#include "EventDistributor.hh"
#include "Command.hh"
#include "TclObject.hh"
#include "CommandException.hh"
#include "MSXCommandController.hh"
#include "MSXMotherBoard.hh"
#include "Setting.hh"
#include "InterpreterOutput.hh"
#include "MSXCPUInterface.hh"
#include "openmsx.hh"
#include "FileOperations.hh"
#include "StringOp.hh"
#include "unreachable.hh"
#include "xrange.hh"
#include <iostream>
//#include <tk.h>
#include "openmsx.hh"

using std::string;
using std::vector;

namespace openmsx {

// See comments in traceProc()
static std::map<long, Setting*> traceMap;
static long traceCount = 0;


static int dummyClose(ClientData /*instanceData*/, Tcl_Interp* /*interp*/)
{
        return 0;
}
static int dummyInput(ClientData /*instanceData*/, char* /*buf*/,
                      int /*bufSize*/, int* /*errorCodePtr*/)
{
        return 0;
}
static void dummyWatch(ClientData /*instanceData*/, int /*mask*/)
{
}
static int dummyGetHandle(ClientData /*instanceData*/, int /*direction*/,
                          ClientData* /*handlePtr*/)
{
        return TCL_ERROR;
}
Tcl_ChannelType Interpreter::channelType = {
        const_cast<char*>("openMSX console"),// Type name
        nullptr,                 // Always non-blocking
        dummyClose,              // Close proc
        dummyInput,              // Input proc
        Interpreter::outputProc, // Output proc
        nullptr,                 // Seek proc
        nullptr,                 // Set option proc
        nullptr,                 // Get option proc
        dummyWatch,              // Watch for events on console
        dummyGetHandle,          // Get a handle from the device
        nullptr,                 // Tcl_DriverClose2Proc
        nullptr,                 // Tcl_DriverBlockModeProc
        nullptr,                 // Tcl_DriverFlushProc
        nullptr,                 // Tcl_DriverHandlerProc
        nullptr,                 // Tcl_DriverWideSeekProc
        nullptr,                 // Tcl_DriverThreadActionProc
        nullptr,                 // Tcl_DriverTruncateProc
};

void Interpreter::init(const char* programName)
{
        Tcl_FindExecutable(programName);
}

Interpreter::Interpreter(EventDistributor& eventDistributor_)
        : eventDistributor(eventDistributor_)
{
        interp = Tcl_CreateInterp();
        Tcl_Preserve(interp);

        // TODO need to investigate this: doesn't work on windows
        /*
        if (Tcl_Init(interp) != TCL_OK) {
                std::cout << "Tcl_Init: " << interp->result << std::endl;
        }
        if (Tk_Init(interp) != TCL_OK) {
                std::cout << "Tk_Init error: " << interp->result << std::endl;
        }
        if (Tcl_Eval(interp, "wm withdraw .") != TCL_OK) {
                std::cout << "wm withdraw error: " << interp->result << std::endl;
        }
        */

        Tcl_Channel channel = Tcl_CreateChannel(&channelType,
                "openMSX console", this, TCL_WRITABLE);
        if (channel) {
                Tcl_SetChannelOption(interp, channel, "-translation", "binary");
                Tcl_SetChannelOption(interp, channel, "-buffering", "line");
                Tcl_SetChannelOption(interp, channel, "-encoding", "utf-8");
        }
        Tcl_SetStdChannel(channel, TCL_STDOUT);

        setVariable("env(OPENMSX_USER_DATA)", FileOperations::getUserDataDir());
        setVariable("env(OPENMSX_SYSTEM_DATA)", FileOperations::getSystemDataDir());

        eventDistributor.registerEventListener(OPENMSX_POLL_EVENT, *this);

}

Interpreter::~Interpreter()
{
        // see comment in MSXCPUInterface::cleanup()
        MSXCPUInterface::cleanup();

        eventDistributor.unregisterEventListener(OPENMSX_POLL_EVENT, *this);

        if (!Tcl_InterpDeleted(interp)) {
                Tcl_DeleteInterp(interp);
        }
        Tcl_Release(interp);

        Tcl_Finalize();
}

void Interpreter::setOutput(InterpreterOutput* output_)
{
        output = output_;
}

int Interpreter::outputProc(ClientData clientData, const char* buf,
                 int toWrite, int* /*errorCodePtr*/)
{
        try {
                auto* output = static_cast<Interpreter*>(clientData)->output;
                string_ref text(buf, toWrite);
                if (!text.empty() && output) {
                        output->output(text);
                }
        } catch (...) {
                UNREACHABLE; // we cannot let exceptions pass through Tcl
        }
        return toWrite;
}

void Interpreter::registerCommand(const string& name, Command& command)
{
        assert(commandTokenMap.find(name) == commandTokenMap.end());
        commandTokenMap[name] = Tcl_CreateObjCommand(
                interp, name.c_str(), commandProc,
                static_cast<ClientData>(&command), nullptr);
}

void Interpreter::unregisterCommand(string_ref name, Command& /*command*/)
{
        auto it = commandTokenMap.find(name);
        assert(it != commandTokenMap.end());
        Tcl_DeleteCommandFromToken(interp, it->second);
        commandTokenMap.erase(it);
}

int Interpreter::commandProc(ClientData clientData, Tcl_Interp* interp,
                           int objc, Tcl_Obj* const objv[])
{
        try {
                auto& command = *static_cast<Command*>(clientData);
                vector<TclObject> tokens;
                tokens.reserve(objc);
                for (auto i : xrange(objc)) {
                        tokens.push_back(TclObject(interp, objv[i]));
                }
                int res = TCL_OK;
                TclObject result(interp);
                try {
                        if (!command.isAllowedInEmptyMachine()) {
                                if (auto controller =
                                        dynamic_cast<MSXCommandController*>(
                                                &command.getCommandController())) {
                                        if (!controller->getMSXMotherBoard().getMachineConfig()) {
                                                throw CommandException(
                                                        "Can't execute command in empty machine");
                                        }
                                }
                        }
                        command.execute(tokens, result);
                } catch (MSXException& e) {
                        PRT_DEBUG(
                                "Interpreter: Got an exception while executing a command: "
                                << e.getMessage());
                        result.setString(e.getMessage());
                        res = TCL_ERROR;
                }
                Tcl_SetObjResult(interp, result.getTclObject());
                return res;
        } catch (...) {
                UNREACHABLE; // we cannot let exceptions pass through Tcl
                return TCL_ERROR;
        }
}

// Returns
//   - build-in Tcl commands
//   - openmsx commands
//   - user-defined procs
vector<string> Interpreter::getCommandNames()
{
        return splitList(execute("info commands"), interp);
}

bool Interpreter::isComplete(const string& command) const
{
        return Tcl_CommandComplete(command.c_str()) != 0;
}

string Interpreter::execute(const string& command)
{
        int success = Tcl_Eval(interp, command.c_str());
        string result =  Tcl_GetStringResult(interp);
        if (success != TCL_OK) {
                throw CommandException(result);
        }
        return result;
}

string Interpreter::executeFile(const string& filename)
{
        int success = Tcl_EvalFile(interp, filename.c_str());
        string result =  Tcl_GetStringResult(interp);
        if (success != TCL_OK) {
                throw CommandException(result);
        }
        return result;
}

static void setVar(Tcl_Interp* interp, const char* name, const char* value)
{
        if (!Tcl_SetVar(interp, name, value, TCL_GLOBAL_ONLY | TCL_LEAVE_ERR_MSG)) {
                // might contain error message of a trace proc
                std::cerr << Tcl_GetStringResult(interp) << std::endl;
        }
}
static const char* getVar(Tcl_Interp* interp, const char* name)
{
        return Tcl_GetVar(interp, name, TCL_GLOBAL_ONLY);
}

void Interpreter::setVariable(const string& name, const string& value)
{
        if (!Tcl_SetVar(interp, name.c_str(), value.c_str(),
                        TCL_GLOBAL_ONLY | TCL_LEAVE_ERR_MSG)) {
                throw CommandException(Tcl_GetStringResult(interp));
        }
}

void Interpreter::unsetVariable(const string& name)
{
        Tcl_UnsetVar(interp, name.c_str(), TCL_GLOBAL_ONLY);
}

const char* Interpreter::getVariable(const string& name) const
{
        return getVar(interp, name.c_str());
}

static string getSafeValueString(Setting& setting)
{
        try {
                return setting.getValueString();
        } catch (MSXException&) {
                return "0"; // 'safe' value, see comment in registerSetting()
        }
}
void Interpreter::registerSetting(Setting& variable, const string& name)
{
        if (const char* tclVarValue = getVariable(name)) {
                // Tcl var already existed, use this value
                try {
                        variable.setValueStringDirect(tclVarValue);
                } catch (MSXException&) {
                        // Ignore: can happen in case of proxy settings when
                        // the current machine doesn't have this setting.
                        // E.g.
                        //   (start with cbios machine)
                        //   set renshaturbo 0
                        //   create_machine
                        //   machine2::load_machine Panasonic_FS-A1GT
                }
        } else {
                // define Tcl var
                setVariable(name, getSafeValueString(variable));
        }

        // The call setVariable() above can already trigger traces on this
        // variable (in Tcl it's possible to already set traces on a variable
        // before that variable is defined). We didn't yet set a trace on it
        // ourselves. So for example on proxy-settings we don't yet delegate
        // read/writes to the actual setting. This means that inside the trace
        // callback we see the value set above instead of the 'actual' value.
        //
        // This scenario can be triggered in the load_icons script by
        // executing the following commands (interactively):
        //   delete_machine machine1
        //   create_machine
        //   machine2::load_machine msx2
        //
        // Before changing the 'safe-value' (see getSafeValueString()) to '0',
        // this gave errors because the load_icons script didn't expect to see
        // 'proxy' (the old 'safe-value') as value.
        //
        // The current solution (choosing '0' as safe value) is not ideal, but
        // good enough for now.
        //
        // A possible better solution is to move Tcl_TraceVar() before
        // setVariable(), I did an initial attempt but there were some
        // problems. TODO investigate this further.

        long traceID = traceCount++;
        traceMap[traceID] = &variable;
        Tcl_TraceVar(interp, name.c_str(),
                     TCL_TRACE_READS | TCL_TRACE_WRITES | TCL_TRACE_UNSETS,
                     traceProc, reinterpret_cast<ClientData>(traceID));
}

void Interpreter::unregisterSetting(Setting& variable, const string& name)
{
        auto it = traceMap.begin();
        while (true) {
                assert(it != traceMap.end());
                if (it->second == &variable) break;
                ++it;
        }

        long traceID = it->first;
        Tcl_UntraceVar(interp, name.c_str(),
                       TCL_TRACE_READS | TCL_TRACE_WRITES | TCL_TRACE_UNSETS,
                       traceProc, reinterpret_cast<ClientData>(traceID));
        traceMap.erase(it);
        unsetVariable(name);
}

static Setting* getTraceSetting(unsigned traceID)
{
        auto it = traceMap.find(traceID);
        return (it != traceMap.end()) ? it->second : nullptr;
}

char* Interpreter::traceProc(ClientData clientData, Tcl_Interp* interp,
                           const char* part1, const char* /*part2*/, int flags)
{
        try {
                // Lookup Setting object that belongs to this Tcl variable.
                //
                // In a previous implementation we passed this object directly
                // as the clientData. However this went wrong in the following
                // scenario:
                //
                //    proc foo {} { carta eject ; carta spmanbow.rom }
                //    bind Q foo
                //    [press Q twice]
                //
                // The problem is that when a SCC cartridge is removed, we
                // delete several settings (e.g. SCC_ch1_mute). While deleting
                // a setting we unset the corresponsing Tcl variable (see
                // unregisterSetting() above), this in turn triggers a
                // TCL_TRACE_UNSET callback (this function). To prevent this
                // callback from triggering we first remove the trace before
                // unsetting the variable. However it seems when a setting is
                // deleted from within an active Tcl proc (like in the example
                // above), the callback is anyway triggered, but only at the
                // end of the proc (so in the foo proc above, the settings
                // are deleted after the first statement, but the callbacks
                // only happen after the second statement). By that time the
                // Setting object is already deleted and the callback function
                // works on a deleted object.
                //
                // To prevent this we don't anymore pass a pointer to the
                // Setting object as clientData, but we lookup the Setting in
                // a map. If the Setting was deleted, we won't find it anymore
                // in the map and return.

                auto traceID = reinterpret_cast<uintptr_t>(clientData);
                auto* variable = getTraceSetting(traceID);
                if (!variable) return nullptr;

                static string static_string;
                if (flags & TCL_TRACE_READS) {
                        try {
                                setVar(interp, part1, variable->getValueString().c_str());
                        } catch (MSXException& e) {
                                static_string = e.getMessage();
                                return const_cast<char*>(static_string.c_str());
                        }
                }
                if (flags & TCL_TRACE_WRITES) {
                        try {
                                const char* v = getVar(interp, part1);
                                string newValue = v ? v : "";
                                variable->setValueStringDirect(newValue);
                                string newValue2 = variable->getValueString();
                                if (newValue != newValue2) {
                                        setVar(interp, part1, newValue2.c_str());
                                }
                        } catch (MSXException& e) {
                                setVar(interp, part1, getSafeValueString(*variable).c_str());
                                static_string = e.getMessage();
                                return const_cast<char*>(static_string.c_str());
                        }
                }
                if (flags & TCL_TRACE_UNSETS) {
                        try {
                                // note we cannot use restoreDefault(), because
                                // that goes via Tcl and the Tcl variable
                                // doesn't exist at this point
                                variable->setValueStringDirect(
                                        variable->getRestoreValueString());
                        } catch (MSXException&) {
                                // for some reason default value is not valid ATM,
                                // keep current value (happened for videosource
                                // setting before turning on (set power on) the
                                // MSX machine)
                        }
                        setVar(interp, part1, getSafeValueString(*variable).c_str());
                        Tcl_TraceVar(interp, part1, TCL_TRACE_READS |
                                        TCL_TRACE_WRITES | TCL_TRACE_UNSETS,
                                     traceProc,
                                     reinterpret_cast<ClientData>(traceID));
                }
        } catch (...) {
                UNREACHABLE; // we cannot let exceptions pass through Tcl
        }
        return nullptr;
}

void Interpreter::createNamespace(const std::string& name)
{
        execute("namespace eval ::" + name + " {}");
}

void Interpreter::deleteNamespace(const std::string& name)
{
        execute("namespace delete ::" + name);
}

vector<string> Interpreter::splitList(const std::string& list)
{
        return splitList(list, interp);
}

vector<string> Interpreter::splitList(const string& list, Tcl_Interp* interp)
{
        int argc;
        const char** argv;
        if (Tcl_SplitList(interp, list.c_str(), &argc, &argv) == TCL_ERROR) {
                throw CommandException(
                        interp ? Tcl_GetStringResult(interp)
                               : "splitList error");
        }
        vector<string> result(argv, argv + argc);
        Tcl_Free(reinterpret_cast<char*>(argv));
        return result;
}

int Interpreter::signalEvent(const std::shared_ptr<const Event>& event)
{
        (void)event;
        assert(event->getType() == OPENMSX_POLL_EVENT);
        poll();
        return 0;
}

void Interpreter::poll()
{
        //Tcl_ServiceAll();
        Tcl_DoOneEvent(TCL_DONT_WAIT);
}

TclParser Interpreter::parse(string_ref command)
{
        return TclParser(interp, command);
}

} // namespace openmsx