"""
 mbed CMSIS-DAP debugger
 Copyright (c) 2016 ARM Limited

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
"""
from __future__ import print_function

from pyOCD.board import MbedBoard
from pyOCD.pyDAPAccess import DAPAccess
import threading
import multiprocessing


def run_in_parallel(function, args_list):
    """Create and run a thread in parallel for each element in args_list

    Wait until all threads finish executing. Throw an exception if an exception
    occurred on any of the threads.
    """
    def _thread_helper(idx, func, args):
        """Run the function and set result to True if there was not error"""
        func(*args)
        result_list[idx] = True

    result_list = [False] * len(args_list)
    thread_list = []
    for idx, args in enumerate(args_list):
        thread = threading.Thread(target=_thread_helper,
                                  args=(idx, function, args))
        thread.start()
        thread_list.append(thread)

    for thread in thread_list:
        thread.join()
    for result in result_list:
        if result is not True:
            raise Exception("Running in thread failed")


def run_in_processes(function, args_list):
    """Create and run a processes in parallel for each element in args_list

    Wait until all processes finish executing. Throw an exception if an
    exception occurred on any of the processes.
    """
    process_list = []
    for args in args_list:
        process = multiprocessing.Process(target=function, args=args)
        process.start()
        process_list.append(process)

    error_during_run = False
    for process in process_list:
        process.join()
        if process.exitcode != 0:
            error_during_run = True
    if error_during_run:
        raise Exception("Running in process failed")


def list_boards(id_list):
    """List all connected DAPLink boards repeatedly

    Assert that they are the same as the id list passed in.
    """
    for _ in range(0, 20):
        device_list = DAPAccess.get_connected_devices()
        found_id_list = [device.get_unique_id() for device in device_list]
        found_id_list.sort()
        assert id_list == found_id_list, "Expected %s, got %s" % \
            (id_list, found_id_list)


def search_and_lock(board_id):
    """Repeatedly lock a board with the given ID"""
    for _ in range(0, 20):
        device = DAPAccess.get_device(board_id)
        device.open()
        device.close()
        with MbedBoard.chooseBoard(board_id=board_id):
            pass


def open_already_opened(board_id):
    """Open a device that is already open to verify it gives an error"""
    device = DAPAccess.get_device(board_id)
    try:
        device.open()
        assert False
    except DAPAccess.DeviceError:
        pass


def parallel_test():
    """Test that devices can be found and opened in parallel"""
    device_list = DAPAccess.get_connected_devices()
    id_list = [device.get_unique_id() for device in device_list]
    id_list.sort()

    if len(id_list) < 2:
        print("Need at least 2 boards to run the parallel test")
        exit(-1)

    # Goal of this file is to test that:
    # -The process of listing available boards does not interfere
    #  with other processes enumerating, opening, or using boards
    # -Opening and using a board does not interfere with another process
    #  processes which is enumerating, opening, or using boards as
    # long as that is not the current board

    print("Listing board from multiple threads at the same time")
    args_list = [(id_list,) for _ in range(5)]
    run_in_parallel(list_boards, args_list)

    print("Listing board from multiple processes at the same time")
    run_in_processes(list_boards, args_list)

    print("Opening same board from multiple threads at the same time")
    device = DAPAccess.get_device(id_list[0])
    device.open()
    open_already_opened(id_list[0])
    args_list = [(id_list[0],) for _ in range(5)]
    run_in_parallel(open_already_opened, args_list)
    device.close()

    print("Opening same board from multiple processes at the same time")
    device = DAPAccess.get_device(id_list[0])
    device.open()
    open_already_opened(id_list[0])
    args_list = [(id_list[0],) for _ in range(5)]
    run_in_processes(open_already_opened, args_list)
    device.close()

    print("Opening different boards from different threads")
    args_list = [(board_id,) for board_id in id_list]
    run_in_parallel(search_and_lock, args_list)

    print("Opening different boards from different processes")
    run_in_processes(search_and_lock, args_list)

    print("Test passed")


if __name__ == "__main__":
    parallel_test()

Add a test for simultaneous device access