//===-- Queue.h ------------------------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef liblldb_Queue_h_
#define liblldb_Queue_h_

#include <vector>
#include <string>

#include "lldb/lldb-forward.h"
#include "lldb/lldb-enumerations.h"
#include "lldb/lldb-private.h"
#include "lldb/Target/QueueItem.h"


namespace lldb_private {

//------------------------------------------------------------------
// Queue:
// This class represents a libdispatch aka Grand Central Dispatch
// queue in the process.  
//
// A program using libdispatch will create queues, put work items
// (functions, blocks) on the queues.  The system will create /
// reassign pthreads to execute the work items for the queues.  A
// serial queue will be associated with a single thread (or possibly
// no thread, if it is not doing any work).  A concurrent queue may
// be associated with multiple threads.
//------------------------------------------------------------------


class Queue :
    public std::enable_shared_from_this<Queue>
{
public:

    Queue (lldb::ProcessSP process_sp, lldb::queue_id_t queue_id, const char *queue_name);

    ~Queue ();

    //------------------------------------------------------------------
    /// Get the QueueID for this Queue
    ///
    /// A 64-bit ID number that uniquely identifies a queue at this particular
    /// stop_id.  Currently the libdispatch serialnum is used for the QueueID;
    /// it is a number that starts at 1 for each process and increments with 
    /// each queue.  A serialnum is not reused for a different queue in the
    /// lifetime of that process execution.
    ///
    /// @return
    ///     The QueueID for this Queue.
    //------------------------------------------------------------------
    lldb::queue_id_t
    GetID ();

    //------------------------------------------------------------------
    /// Get the name of this Queue
    ///
    /// @return
    ///     The name of the queue, if one is available.  
    ///     A NULL pointer is returned if none is available.
    //------------------------------------------------------------------
    const char *
    GetName ();

    //------------------------------------------------------------------
    /// Get the IndexID for this Queue
    ///
    /// This is currently the same as GetID().  If it changes in the future,
    /// it will be  a small integer value (starting with 1) assigned to
    /// each queue that is seen during a Process lifetime.  
    /// 
    /// Both the GetID and GetIndexID are being retained for Queues to
    /// maintain similar API to the Thread class, and allow for the 
    /// possibility of GetID changing to a different source in the future.
    ///
    /// @return
    ///     The IndexID for this queue.
    //------------------------------------------------------------------
    uint32_t
    GetIndexID ();

    //------------------------------------------------------------------
    /// Return the threads currently associated with this queue
    ///
    /// Zero, one, or many threads may be executing code for a queue at
    /// a given point in time.  This call returns the list of threads
    /// that are currently executing work for this queue.
    ///
    /// @return
    ///     The threads currently performing work for this queue
    //------------------------------------------------------------------
    std::vector<lldb::ThreadSP>
    GetThreads ();

    //------------------------------------------------------------------
    /// Return the items that are currently enqueued
    ///
    /// "Enqueued" means that the item has been added to the queue to
    /// be done, but has not yet been done.  When the item is going to
    /// be processed it is "dequeued".
    ///
    /// @return
    ///     The vector of enqueued items for this queue
    //------------------------------------------------------------------
    const std::vector<lldb::QueueItemSP> &
    GetPendingItems();

    lldb::ProcessSP
    GetProcess() const
    {
        return m_process_wp.lock(); 
    }

    //------------------------------------------------------------------
    /// Get the number of work items that this queue is currently running
    ///
    /// @return
    ///     The number of work items currently executing.  For a serial 
    ///     queue, this will be 0 or 1.  For a concurrent queue, this 
    ///     may be any number.
    //------------------------------------------------------------------
    uint32_t
    GetNumRunningWorkItems () const;

    //------------------------------------------------------------------
    /// Get the number of work items enqueued on this queue
    ///
    /// @return
    ///     The number of work items currently enqueued, waiting to
    ///     execute.
    //------------------------------------------------------------------
    uint32_t
    GetNumPendingWorkItems () const;

    //------------------------------------------------------------------
    /// Get the dispatch_queue_t structure address for this Queue
    ///
    /// Get the address in the inferior process' memory of this Queue's
    /// dispatch_queue_t structure.
    ///
    /// @return
    ///     The address of the dispatch_queue_t structure, if known.
    ///     LLDB_INVALID_ADDRESS will be returned if it is unavailable.
    //------------------------------------------------------------------
    lldb::addr_t
    GetLibdispatchQueueAddress () const;


    void
    SetNumRunningWorkItems (uint32_t count);

    void
    SetNumPendingWorkItems (uint32_t count);

    void
    SetLibdispatchQueueAddress (lldb::addr_t dispatch_queue_t_addr);

    void
    PushPendingQueueItem (lldb::QueueItemSP item)
    {
        m_pending_items.push_back (item);
    }

private:
    //------------------------------------------------------------------
    // For Queue only
    //------------------------------------------------------------------

    lldb::ProcessWP                 m_process_wp;
    lldb::queue_id_t                m_queue_id;
    std::string                     m_queue_name;
    uint32_t                        m_running_work_items_count;
    uint32_t                        m_pending_work_items_count;
    std::vector<lldb::QueueItemSP>  m_pending_items;
    lldb::addr_t                    m_dispatch_queue_t_addr;  // address of libdispatch dispatch_queue_t for this Queue

    DISALLOW_COPY_AND_ASSIGN (Queue);
};

} // namespace lldb_private

#endif  // liblldb_Queue_h_