TclObject.hh

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#ifndef TCLOBJECT_HH
#define TCLOBJECT_HH

#include "string_view.hh"
#include "openmsx.hh"
#include "xxhash.hh"
#include <tcl.h>
#include <iterator>
#include <cassert>

struct Tcl_Obj;

namespace openmsx {

class Interpreter;

class TclObject
{
        // For STL interface, see below
        struct iterator {
                iterator(const TclObject& obj_, unsigned i_)
                        : obj(&obj_), i(i_) {}

                bool operator==(const iterator& other) const {
                        assert(obj == other.obj);
                        return i == other.i;
                }
                bool operator!=(const iterator& other) const {
                        return !(*this == other);
                }

                string_view operator*() const {
                        return obj->getListIndexUnchecked(i).getString();
                }

                iterator& operator++() {
                        ++i;
                        return *this;
                }
                iterator operator++(int) {
                        iterator result = *this;
                        ++result;
                        return result;
                }
                iterator& operator--() {
                        --i;
                        return *this;
                }
                iterator operator--(int) {
                        iterator result = *this;
                        --result;
                        return result;
                }
        private:
                const TclObject* obj;
                unsigned i;
        };

public:
        TclObject()                      { init(Tcl_NewObj()); }
        explicit TclObject(Tcl_Obj* o)   { init(o); }
        explicit TclObject(string_view v) { init(Tcl_NewStringObj(v.data(), int(v.size()))); }
        explicit TclObject(int v)        { init(Tcl_NewIntObj(v)); }
        explicit TclObject(double v)     { init(Tcl_NewDoubleObj(v)); }
        TclObject(const TclObject&  o)   { init(o.obj); }
        TclObject(      TclObject&& o) noexcept { init(o.obj); }
        ~TclObject()                     { Tcl_DecrRefCount(obj); }

        // assignment operator so we can use vector<TclObject>
        TclObject& operator=(const TclObject& other) {
                if (&other != this) {
                        Tcl_DecrRefCount(obj);
                        init(other.obj);
                }
                return *this;
        }
        TclObject& operator=(TclObject&& other) noexcept {
                std::swap(obj, other.obj);
                return *this;
        }

        // get underlying Tcl_Obj
        Tcl_Obj* getTclObject() { return obj; }
        Tcl_Obj* getTclObjectNonConst() const { return const_cast<Tcl_Obj*>(obj); }

        // value setters
        void setString(string_view value);
        void setInt(int value);
        void setBoolean(bool value);
        void setDouble(double value);
        void setBinary(byte* buf, unsigned length);
        void addListElement(string_view element);
        void addListElement(int value);
        void addListElement(double value);
        void addListElement(const TclObject& element);
        template <typename ITER> void addListElements(ITER begin, ITER end);
        template <typename CONT> void addListElements(const CONT& container);

        // value getters
        string_view getString() const;
        int getInt      (Interpreter& interp) const;
        bool getBoolean (Interpreter& interp) const;
        double getDouble(Interpreter& interp) const;
        const byte* getBinary(unsigned& length) const;
        unsigned getListLength(Interpreter& interp) const;
        TclObject getListIndex(Interpreter& interp, unsigned index) const;
        TclObject getDictValue(Interpreter& interp, const TclObject& key) const;

        // STL-like interface when interpreting this TclObject as a list of
        // strings. Invalid Tcl lists are silently interpreted as empty lists.
        unsigned size() const { return getListLengthUnchecked(); }
        bool empty() const { return size() == 0; }
        iterator begin() const { return iterator(*this, 0); }
        iterator end()   const { return iterator(*this, size()); }

        // expressions
        bool evalBool(Interpreter& interp) const;

        TclObject executeCommand(Interpreter& interp, bool compile = false);

        friend bool operator==(const TclObject& x, const TclObject& y) {
                return x.getString() == y.getString();
        }
        friend bool operator==(const TclObject& x, string_view y) {
                return x.getString() == y;
        }
        friend bool operator==(string_view x, const TclObject& y) {
                return x == y.getString();
        }

        friend bool operator!=(const TclObject& x, const TclObject& y) { return !(x == y); }
        friend bool operator!=(const TclObject& x, string_view       y) { return !(x == y); }
        friend bool operator!=(string_view       x, const TclObject& y) { return !(x == y); }

private:
        void init(Tcl_Obj* obj_) noexcept {
                obj = obj_;
                Tcl_IncrRefCount(obj);
        }

        void addListElement(Tcl_Obj* element);
        unsigned getListLengthUnchecked() const;
        TclObject getListIndexUnchecked(unsigned index) const;

        Tcl_Obj* obj;
};

template <typename ITER>
void TclObject::addListElements(ITER first, ITER last)
{
        for (ITER it = first; it != last; ++it) {
                addListElement(*it);
        }
}

template <typename CONT>
void TclObject::addListElements(const CONT& container)
{
        addListElements(std::begin(container), std::end(container));
}

// We want to be able to reinterpret_cast a Tcl_Obj* as a TclObject.
static_assert(sizeof(TclObject) == sizeof(Tcl_Obj*), "");


struct XXTclHasher {
        uint32_t operator()(string_view str) const {
                return xxhash(str);
        }
        uint32_t operator()(const TclObject& obj) const {
                return xxhash(obj.getString());
        }
};

} // namespace openmsx

#endif