| | | 1 | | using System; |
| | | 2 | | using System.Threading; |
| | | 3 | | |
| | | 4 | | namespace Renci.SshNet.Common |
| | | 5 | | { |
| | | 6 | | /// <summary> |
| | | 7 | | /// Base class to encapsulates the results of an asynchronous operation. |
| | | 8 | | /// </summary> |
| | | 9 | | public abstract class AsyncResult : IAsyncResult |
| | | 10 | | { |
| | | 11 | | private const int StatePending = 0; |
| | | 12 | | |
| | | 13 | | private const int StateCompletedSynchronously = 1; |
| | | 14 | | |
| | | 15 | | private const int StateCompletedAsynchronously = 2; |
| | | 16 | | |
| | | 17 | | private readonly AsyncCallback _asyncCallback; |
| | | 18 | | private readonly object _asyncState; |
| | 4548 | 19 | | private int _completedState = StatePending; |
| | | 20 | | private ManualResetEvent _asyncWaitHandle; |
| | | 21 | | private Exception _exception; |
| | | 22 | | |
| | | 23 | | /// <summary> |
| | | 24 | | /// Initializes a new instance of the <see cref="AsyncResult"/> class. |
| | | 25 | | /// </summary> |
| | | 26 | | /// <param name="asyncCallback">The async callback.</param> |
| | | 27 | | /// <param name="state">The state.</param> |
| | 4548 | 28 | | protected AsyncResult(AsyncCallback asyncCallback, object state) |
| | 4548 | 29 | | { |
| | 4548 | 30 | | _asyncCallback = asyncCallback; |
| | 4548 | 31 | | _asyncState = state; |
| | 4548 | 32 | | } |
| | | 33 | | |
| | | 34 | | /// <summary> |
| | | 35 | | /// Gets a value indicating whether <see cref="EndInvoke()"/> has been called on the current <see cref="AsyncRes |
| | | 36 | | /// </summary> |
| | | 37 | | /// <value> |
| | | 38 | | /// <see langword="true"/> if <see cref="EndInvoke()"/> has been called on the current <see cref="AsyncResult"/> |
| | | 39 | | /// otherwise, <see langword="false"/>. |
| | | 40 | | /// </value> |
| | 4553 | 41 | | public bool EndInvokeCalled { get; private set; } |
| | | 42 | | |
| | | 43 | | /// <summary> |
| | | 44 | | /// Marks asynchronous operation as completed. |
| | | 45 | | /// </summary> |
| | | 46 | | /// <param name="exception">The exception.</param> |
| | | 47 | | /// <param name="completedSynchronously">If set to <see langword="true"/>, completed synchronously.</param> |
| | | 48 | | public void SetAsCompleted(Exception exception, bool completedSynchronously) |
| | 4310 | 49 | | { |
| | | 50 | | // Passing null for exception means no error occurred; this is the common case |
| | 4310 | 51 | | _exception = exception; |
| | | 52 | | |
| | | 53 | | // The '_completedState' field MUST be set prior calling the callback |
| | 4310 | 54 | | var prevState = Interlocked.Exchange(ref _completedState, |
| | 4310 | 55 | | completedSynchronously ? StateCompletedSynchronously : StateCompletedAs |
| | | 56 | | |
| | 4310 | 57 | | if (prevState != StatePending) |
| | 0 | 58 | | { |
| | 0 | 59 | | throw new InvalidOperationException("You can set a result only once"); |
| | | 60 | | } |
| | | 61 | | |
| | | 62 | | // If the event exists, set it |
| | 4310 | 63 | | _ = _asyncWaitHandle?.Set(); |
| | | 64 | | |
| | | 65 | | // If a callback method was set, call it |
| | 4310 | 66 | | _asyncCallback?.Invoke(this); |
| | 4310 | 67 | | } |
| | | 68 | | |
| | | 69 | | /// <summary> |
| | | 70 | | /// Waits until the asynchronous operation completes, and then returns. |
| | | 71 | | /// </summary> |
| | | 72 | | internal void EndInvoke() |
| | 4303 | 73 | | { |
| | | 74 | | // This method assumes that only 1 thread calls EndInvoke for this object |
| | 4303 | 75 | | if (!IsCompleted) |
| | 12 | 76 | | { |
| | | 77 | | // If the operation isn't done, wait for it |
| | 12 | 78 | | _ = AsyncWaitHandle.WaitOne(); |
| | 12 | 79 | | _asyncWaitHandle = null; // Allow early GC |
| | 12 | 80 | | AsyncWaitHandle.Dispose(); |
| | 12 | 81 | | } |
| | | 82 | | |
| | 4303 | 83 | | EndInvokeCalled = true; |
| | | 84 | | |
| | | 85 | | // Operation is done: if an exception occurred, throw it |
| | 4303 | 86 | | if (_exception != null) |
| | 40 | 87 | | { |
| | 40 | 88 | | throw _exception; |
| | | 89 | | } |
| | 4263 | 90 | | } |
| | | 91 | | |
| | | 92 | | /// <summary> |
| | | 93 | | /// Gets a user-defined object that qualifies or contains information about an asynchronous operation. |
| | | 94 | | /// </summary> |
| | | 95 | | /// <returns> |
| | | 96 | | /// A user-defined object that qualifies or contains information about an asynchronous operation. |
| | | 97 | | /// </returns> |
| | | 98 | | public object AsyncState |
| | | 99 | | { |
| | 12090 | 100 | | get { return _asyncState; } |
| | | 101 | | } |
| | | 102 | | |
| | | 103 | | /// <summary> |
| | | 104 | | /// Gets a value indicating whether the asynchronous operation completed synchronously. |
| | | 105 | | /// </summary> |
| | | 106 | | /// <returns> |
| | | 107 | | /// <see langword="true"/> if the asynchronous operation completed synchronously; otherwise, <see langword="fals |
| | | 108 | | /// </returns> |
| | | 109 | | public bool CompletedSynchronously |
| | | 110 | | { |
| | 24 | 111 | | get { return _completedState == StateCompletedSynchronously; } |
| | | 112 | | } |
| | | 113 | | |
| | | 114 | | /// <summary> |
| | | 115 | | /// Gets a <see cref="WaitHandle"/> that is used to wait for an asynchronous operation to complete. |
| | | 116 | | /// </summary> |
| | | 117 | | /// <returns> |
| | | 118 | | /// A <see cref="WaitHandle"/> that is used to wait for an asynchronous operation to complete. |
| | | 119 | | /// </returns> |
| | | 120 | | public WaitHandle AsyncWaitHandle |
| | | 121 | | { |
| | | 122 | | get |
| | 232 | 123 | | { |
| | 232 | 124 | | if (_asyncWaitHandle is null) |
| | 231 | 125 | | { |
| | 231 | 126 | | var done = IsCompleted; |
| | 231 | 127 | | var mre = new ManualResetEvent(done); |
| | 231 | 128 | | if (Interlocked.CompareExchange(ref _asyncWaitHandle, mre, comparand: null) != null) |
| | 0 | 129 | | { |
| | | 130 | | // Another thread created this object's event; dispose the event we just created |
| | 0 | 131 | | mre.Dispose(); |
| | 0 | 132 | | } |
| | | 133 | | else |
| | 231 | 134 | | { |
| | 231 | 135 | | if (!done && IsCompleted) |
| | 0 | 136 | | { |
| | | 137 | | // If the operation wasn't done when we created the event but now it is done, set the event |
| | 0 | 138 | | _ = _asyncWaitHandle.Set(); |
| | 0 | 139 | | } |
| | 231 | 140 | | } |
| | 231 | 141 | | } |
| | | 142 | | |
| | 232 | 143 | | return _asyncWaitHandle; |
| | 232 | 144 | | } |
| | | 145 | | } |
| | | 146 | | |
| | | 147 | | /// <summary> |
| | | 148 | | /// Gets a value indicating whether the asynchronous operation has completed. |
| | | 149 | | /// </summary> |
| | | 150 | | /// <returns> |
| | | 151 | | /// <see langword="true"/> if the operation is complete; otherwise, <see langword="false"/>. |
| | | 152 | | /// </returns> |
| | | 153 | | public bool IsCompleted |
| | | 154 | | { |
| | 15678 | 155 | | get { return _completedState != StatePending; } |
| | | 156 | | } |
| | | 157 | | } |
| | | 158 | | } |