/* -*- mode: c++; indent-tabs-mode: nil -*- */
/*
    QoreQueue.h

    Qore Programming Language

    Copyright (C) 2003 - 2023 Qore Technologies, s.r.o.

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
    DEALINGS IN THE SOFTWARE.

    Note that the Qore library is released under a choice of three open-source
    licenses: MIT (as above), LGPL 2+, or GPL 2+; see README-LICENSE for more
    information.
*/

#ifndef _QORE_QOREQUEUE_H

#define _QORE_QOREQUEUE_H

#include <qore/QoreThreadLock.h>
#include <qore/QoreCondition.h>

class QoreQueueNode;

class qore_queue_private;

class QoreQueue {
    friend class qore_queue_private;
protected:
    // private implementation
    qore_queue_private* priv;

public:
    //! creates the queue with the given maximum size; -1 means no maximum size
    DLLEXPORT QoreQueue(int n_max = -1);

    //! copy constructor
    DLLEXPORT QoreQueue(const QoreQueue& orig);

    //! destructor
    /** queues should not be deleted when other threads might be accessing them
    */
    DLLEXPORT ~QoreQueue();

    //! push at the end of the queue and take the reference; can only be used when len == -1
    DLLEXPORT void pushAndTakeRef(QoreValue n);

    //! push at the end of the queue
    DLLEXPORT void push(ExceptionSink* xsink, QoreValue n, int timeout_ms = 0, bool* to = 0);

    //! insert at the beginning of the queue
    DLLEXPORT void insert(ExceptionSink* xsink, QoreValue n, int timeout_ms = 0, bool* to = 0);

    //! push at the end of the queue and scan for recursive references
    /**
        @since %Qore 0.9
    */
    DLLEXPORT void push(ExceptionSink* xsink, QoreObject* self, QoreValue n, int timeout_ms = 0, bool* to = nullptr);

    //! insert at the beginning of the queue and scan for recursive references
    /**
        @since %Qore 0.9
    */
    DLLEXPORT void insert(ExceptionSink* xsink, QoreObject* self, QoreValue n, int timeout_ms = 0, bool* to = nullptr);

    //! remove a node from the beginning of the queue
    DLLEXPORT QoreValue shift(ExceptionSink* xsink, int timeout_ms = 0, bool* to = nullptr);

    //! remove a node from the end of the queue
    DLLEXPORT QoreValue pop(ExceptionSink* xsink, int timeout_ms = 0, bool* to = nullptr);

    //! remove a node from the beginning of the queue and manage recursive references
    /**
        @since %Qore 0.9
    */
    DLLEXPORT QoreValue shift(ExceptionSink* xsink, QoreObject* self, int timeout_ms = 0, bool* to = nullptr);

    //! remove a node from the end of the queue and manage recursive references
    /**
        @since %Qore 0.9
    */
    DLLEXPORT QoreValue pop(ExceptionSink* xsink, QoreObject* self, int timeout_ms = 0, bool* to = nullptr);

    //! returns true if the queue is empty
    DLLEXPORT bool empty() const;

    //! returns the number of elements in the queue
    DLLEXPORT size_t size() const;

    //! returns the maximum size of the queue
    DLLEXPORT ptrdiff_t getMax() const;

    //! returns the number of threads currently waiting to read data
    DLLEXPORT size_t getReadWaiting() const;

    //! returns the number of threads currently waiting to write data
    DLLEXPORT size_t getWriteWaiting() const;

    //! clears the queue
    DLLEXPORT void clear(ExceptionSink* xsink);

    //! clears the queue
    /**
        @since %Qore 0.9
    */
    DLLEXPORT void clear(ExceptionSink* xsink, QoreObject* self);

    //! sets a queue error status and provides exception information to throw if queue operations are attempted; the queue is also cleared and can no longer be written to after this operation
    /** if called more than once, subsequent calls replace the data in the object

        @since Qore 0.8.12
    */
    DLLEXPORT void setError(const char* err, const QoreStringNode* desc, ExceptionSink* xsink);

    //! sets a queue error status and provides exception information to throw if queue operations are attempted; the queue is also cleared and can no longer be written to after this operation
    /** if called more than once, subsequent calls replace the data in the object

        @since Qore 0.9
    */
    DLLEXPORT void setError(const char* err, const QoreStringNode* desc, QoreObject* self, ExceptionSink* xsink);

    //! clears any queue error status to make the object usable again
    /**
        @since Qore 0.8.12
    */
    DLLEXPORT void clearError();
};

class Queue : public AbstractPrivateData, public QoreQueue {
protected:
    DLLEXPORT virtual ~Queue();

public:
    DLLEXPORT Queue(int max = -1);

    DLLEXPORT Queue(const Queue& old);

    DLLEXPORT Queue* queueRefSelf() const;

    DLLEXPORT virtual void deref(ExceptionSink* xsink);
};

#endif // _QORE_QOREQUEUE_H
