vthread.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef MTROPOLIS_VTHREAD_H
#define MTROPOLIS_VTHREAD_H

#include "mtropolis/coroutine_protos.h"
#include "mtropolis/coroutine_return_value.h"
#include "mtropolis/debug.h"

namespace MTropolis {

struct ICoroutineManager;
class VThread;

// Virtual thread, really a task stack
enum VThreadState {
    kVThreadReturn,
    kVThreadSuspended,
    kVThreadError,
};

struct VThreadFaultIdentifier {
};

template<typename T>
struct VThreadFaultIdentifierSingleton {
    static VThreadFaultIdentifier _identifier;
};

template<typename T>
VThreadFaultIdentifier VThreadFaultIdentifierSingleton<T>::_identifier;

class VThreadTaskData : public Debuggable {
public:
    VThreadTaskData();
    virtual ~VThreadTaskData();

    virtual VThreadState execute(VThread *thread) = 0;

#ifdef MTROPOLIS_DEBUG_ENABLE
public:
    void debugInit(const char *name);

protected:
    SupportStatus debugGetSupportStatus() const override { return kSupportStatusDone; }
    const char *debugGetTypeName() const override { return "Task"; }
    const Common::String &debugGetName() const override { return _debugName; }
    void debugInspect(IDebugInspectionReport *report) const override;

    Common::String _debugName;
#endif
};

struct VThreadStackFrame;

class VThreadStackChunk {
public:
    explicit VThreadStackChunk(size_t capacity);
    VThreadStackChunk(VThreadStackChunk &&other);
    ~VThreadStackChunk();

    VThreadStackFrame *_topFrame;
    byte *_memory;
    size_t _size;

private:
    VThreadStackChunk() = delete;
    VThreadStackChunk(const VThreadStackChunk &) = delete;
};

struct VThreadStackFrame {
    VThreadTaskData *data;
    VThreadStackFrame *prevFrame;
    bool isLastInChunk;
};

template<typename TClass, typename TData>
class VThreadMethodData : public VThreadTaskData {
public:
    VThreadMethodData(const VThreadFaultIdentifier *faultID, TClass *target, VThreadState (TClass::*method)(const TData &data));
    VThreadMethodData(const VThreadMethodData &other);
    VThreadMethodData(VThreadMethodData &&other);

    VThreadState execute(VThread *thread) override;

    TData &getData();

private:
    const VThreadFaultIdentifier *_faultID;
    TClass *_target;
    VThreadState (TClass::*_method)(const TData &data);
    TData _data;
};

template<typename TData>
class VThreadFunctionData : public VThreadTaskData {

public:
    explicit VThreadFunctionData(const VThreadFaultIdentifier *faultID, VThreadState (*func)(const TData &data));
    VThreadFunctionData(const VThreadFunctionData &other);

    VThreadFunctionData(VThreadFunctionData &&other);

    VThreadState execute(VThread *thread) override;

    TData &getData();

private:
    const VThreadFaultIdentifier *_faultID;
    VThreadState (*_func)(const TData &data);
    TData _data;
};

class VThread {
public:
    explicit VThread(ICoroutineManager *coroManager);
    ~VThread();

    template<typename TClass, typename TData>
    TData *pushTask(const char *name, TClass *obj, VThreadState (TClass::*method)(const TData &data));

    template<typename TData>
    TData *pushTask(const char *name, VThreadState (*func)(const TData &data));

    VThreadState step();

    bool hasTasks() const;

    bool popFrame();

    VThreadTaskData *pushCoroutineFrame(const CompiledCoroutine *compiledCoro, const CoroutineParamsBase &params, const CoroutineReturnValueRefBase &returnValueRef);

    template<typename TCoroutine, typename TReturnValue, typename ...TParams>
    void pushCoroutineWithReturn(TReturnValue *returnValuePtr, TParams &&...args);

    template<typename TCoroutine, typename TReturnValue>
    void pushCoroutineWithReturn(TReturnValue *returnValuePtr);

    template<typename TCoroutine, typename... TParams>
    void pushCoroutine(TParams &&...args);

    template<typename TCoroutine>
    void pushCoroutine();


private:
    void reserveFrame(size_t frameAlignment, size_t frameSize, VThreadStackFrame *&outFramePtr, size_t dataAlignment, size_t dataSize, void *&outDataPtr, bool &outIsNewChunk);
    static bool reserveFrameInChunk(VThreadStackChunk *chunk, size_t frameAlignment, size_t frameSize, VThreadStackFrame *&outFramePtr, size_t dataAlignment, size_t dataSize, void *&outDataPtr);

    void pushCoroutineInternal(CompiledCoroutine **compiledCoroPtr, CoroutineCompileFunction_t compileFunc, bool isVoidReturn, const CoroutineParamsBase &params, const CoroutineReturnValueRefBase &returnValueRef);

    template<typename TClass, typename TData>
    TData *pushTaskWithFaultHandler(const VThreadFaultIdentifier *faultID, const char *name, TClass *obj, VThreadState (TClass::*method)(const TData &data));

    template<typename TData>
    TData *pushTaskWithFaultHandler(const VThreadFaultIdentifier *faultID, const char *name, VThreadState (*func)(const TData &data));

    Common::Array<VThreadStackChunk> _stackChunks;
    ICoroutineManager *_coroManager;
    uint _numActiveStackChunks;
};

template<typename TClass, typename TData>
VThreadMethodData<TClass, TData>::VThreadMethodData(const VThreadFaultIdentifier *faultID, TClass *target, VThreadState (TClass::*method)(const TData &data))
    : _faultID(faultID), _target(target), _method(method) {
}

template<typename TClass, typename TData>
VThreadMethodData<TClass, TData>::VThreadMethodData(const VThreadMethodData& other)
    : _faultID(other._faultID), _target(other._target), _method(other._method), _data(other._data) {
}

template<typename TClass, typename TData>
VThreadMethodData<TClass, TData>::VThreadMethodData(VThreadMethodData &&other)
    : _faultID(other._faultID), _target(other._target), _method(other._method), _data(static_cast<TData &&>(other._data)) {
}

template<typename TClass, typename TData>
VThreadState VThreadMethodData<TClass, TData>::execute(VThread *thread) {
    TData data(static_cast<TData &&>(_data));

    TClass *target = _target;
    VThreadState (TClass::*method)(const TData &) = _method;

    thread->popFrame();

    return (target->*method)(data);
}

template<typename TClass, typename TData>
TData &VThreadMethodData<TClass, TData>::getData() {
    return _data;
}

template<typename TData>
VThreadFunctionData<TData>::VThreadFunctionData(const VThreadFaultIdentifier *faultID, VThreadState (*func)(const TData &data))
    : _faultID(faultID), _func(func) {
}

template<typename TData>
VThreadFunctionData<TData>::VThreadFunctionData(const VThreadFunctionData &other)
    : _faultID(other._faultID), _func(other._func), _data(other._data) {
}

template<typename TData>
VThreadFunctionData<TData>::VThreadFunctionData(VThreadFunctionData &&other)
    : _faultID(other._faultID), _func(other._func), _data(static_cast<TData &&>(other._data)) {
}

template<typename TData>
VThreadState VThreadFunctionData<TData>::execute(VThread *thread) {
    TData data(static_cast<TData &&>(_data));

    VThreadState (*func)(const TData &) = _func;

    thread->popFrame();

    return func(data);
}

template<typename TData>
TData &VThreadFunctionData<TData>::getData() {
    return _data;
}

template<typename TCoroutine, typename TReturnValue, typename... TParams>
void VThread::pushCoroutineWithReturn(TReturnValue *returnValuePtr, TParams &&...args) {
    assert(returnValuePtr != nullptr);
    this->pushCoroutineInternal(&TCoroutine::ms_compiledCoro, TCoroutine::compileCoroutine, CoroutineReturnValueRef<typename TCoroutine::ReturnValue_t>::isVoid(), typename TCoroutine::Params(Common::forward<TParams>(args)...), CoroutineReturnValueRef<typename TCoroutine::ReturnValue_t>(returnValuePtr));
}

template<typename TCoroutine, typename TReturnValue>
void VThread::pushCoroutineWithReturn(TReturnValue *returnValuePtr) {
    assert(returnValuePtr != nullptr);
    this->pushCoroutineInternal(&TCoroutine::ms_compiledCoro, TCoroutine::compileCoroutine, CoroutineReturnValueRef<typename TCoroutine::ReturnValue_t>::isVoid(), typename TCoroutine::Params(), CoroutineReturnValueRef<typename TCoroutine::ReturnValue_t>(returnValuePtr));
}

template<typename TCoroutine, typename... TParams>
void VThread::pushCoroutine(TParams &&...args) {
    this->pushCoroutineInternal(&TCoroutine::ms_compiledCoro, TCoroutine::compileCoroutine, CoroutineReturnValueRef<typename TCoroutine::ReturnValue_t>::isVoid(), typename TCoroutine::Params(Common::forward<TParams>(args)...), CoroutineReturnValueRef<typename TCoroutine::ReturnValue_t>());
}

template<typename TCoroutine>
void VThread::pushCoroutine() {
    this->pushCoroutineInternal(&TCoroutine::ms_compiledCoro, TCoroutine::compileCoroutine, CoroutineReturnValueRef<typename TCoroutine::ReturnValue_t>::isVoid(), typename TCoroutine::Params(), CoroutineReturnValueRef<typename TCoroutine::ReturnValue_t>());
}

template<typename TClass, typename TData>
TData *VThread::pushTask(const char *name, TClass *obj, VThreadState (TClass::*method)(const TData &data)) {
    return this->pushTaskWithFaultHandler(nullptr, name, obj, method);
}

template<typename TData>
TData *VThread::pushTask(const char *name, VThreadState (*func)(const TData &data)) {
    return this->pushTaskWithFaultHandler(nullptr, name, func);
}

template<typename TClass, typename TData>
TData *VThread::pushTaskWithFaultHandler(const VThreadFaultIdentifier *faultID, const char *name, TClass *obj, VThreadState (TClass::*method)(const TData &data)) {
    typedef VThreadMethodData<TClass, TData> FrameData_t;

    const size_t frameAlignment = alignof(VThreadStackFrame);
    const size_t dataAlignment = alignof(FrameData_t);

    VThreadStackFrame *prevFrame = nullptr;
    if (_numActiveStackChunks > 0)
        prevFrame = _stackChunks[_numActiveStackChunks - 1]._topFrame;

    VThreadStackFrame *framePtr = nullptr;
    void *dataPtr = nullptr;
    bool isNewChunk = false;
    reserveFrame(frameAlignment, sizeof(VThreadStackFrame), framePtr, dataAlignment, sizeof(FrameData_t), dataPtr, isNewChunk);

    VThreadStackFrame *frame = new (framePtr) VThreadStackFrame();
    FrameData_t *frameData = new (dataPtr) FrameData_t(faultID, obj, method);

    frame->data = frameData;
    frame->prevFrame = prevFrame;
    frame->isLastInChunk = isNewChunk;

#ifdef MTROPOLIS_DEBUG_ENABLE
    frameData->debugInit(name);
#endif

    return &frameData->getData();
}

template<typename TData>
TData *VThread::pushTaskWithFaultHandler(const VThreadFaultIdentifier *faultID, const char *name, VThreadState (*func)(const TData &data)) {
    typedef VThreadFunctionData<TData> FrameData_t;

    const size_t frameAlignment = alignof(VThreadStackFrame);
    const size_t dataAlignment = alignof(FrameData_t);

    VThreadStackFrame *prevFrame = nullptr;
    if (_numActiveStackChunks > 0)
        prevFrame = _stackChunks[_numActiveStackChunks - 1]._topFrame;

    VThreadStackFrame *framePtr = nullptr;
    void *dataPtr = nullptr;
    bool isNewChunk = false;
    reserveFrame(frameAlignment, sizeof(VThreadStackFrame), framePtr, dataAlignment, sizeof(FrameData_t), dataPtr, isNewChunk);

    VThreadStackFrame *frame = new (framePtr) VThreadStackFrame();
    FrameData_t *frameData = new (dataPtr) FrameData_t(faultID, func);

    frame->data = frameData;
    frame->prevFrame = prevFrame;
    frame->isLastInChunk = isNewChunk;

#ifdef MTROPOLIS_DEBUG_ENABLE
    frameData->debugInit(name);
#endif

    return &frameData->getData();
}

} // End of namespace MTropolis

#endif