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| 1 | +using System; |
| 2 | +using System.Collections.Generic; |
| 3 | +using System.Diagnostics.CodeAnalysis; |
| 4 | +using System.Linq; |
| 5 | +using System.Runtime.CompilerServices; |
| 6 | +using System.Text; |
| 7 | + |
| 8 | +namespace TimeProviderExtensions; |
| 9 | + |
| 10 | +/// <summary> |
| 11 | +/// Represents a test implementation of a <see cref="TimeProvider"/>, |
| 12 | +/// where time stands still until you call <see cref="ForwardTime(TimeSpan)"/> |
| 13 | +/// or <see cref="SetUtcNow(DateTimeOffset)"/>. |
| 14 | +/// </summary> |
| 15 | +/// <remarks> |
| 16 | +/// Learn more at <see href="https://github.com/egil/TimeProviderExtensions"/>. |
| 17 | +/// </remarks> |
| 18 | +public class ManualTimeProvider : TimeProvider |
| 19 | +{ |
| 20 | + internal const uint MaxSupportedTimeout = 0xfffffffe; |
| 21 | + internal const uint UnsignedInfinite = unchecked((uint)-1); |
| 22 | + |
| 23 | + private readonly List<ManualTimerScheduledCallback> futureCallbacks = new(); |
| 24 | + private DateTimeOffset utcNow; |
| 25 | + |
| 26 | + /// <summary> |
| 27 | + /// Gets the frequency of <see cref="GetTimestamp"/> of high-frequency value per second. |
| 28 | + /// </summary> |
| 29 | + /// <remarks> |
| 30 | + /// This implementation bases timestamp on <see cref="DateTimeOffset.UtcTicks"/>, which is 10,000 ticks per millisecond, |
| 31 | + /// since the progression of time is represented by the date and time returned from <see cref="GetUtcNow()" />. |
| 32 | + /// </remarks> |
| 33 | + public override long TimestampFrequency { get; } = 10_000_000; |
| 34 | + |
| 35 | + /// <summary> |
| 36 | + /// Creates an instance of the <see cref="ManualTimeProvider"/> with |
| 37 | + /// <see cref="DateTimeOffset.UtcNow"/> being the initial value returned by <see cref="GetUtcNow()"/>. |
| 38 | + /// </summary> |
| 39 | + public ManualTimeProvider() |
| 40 | + : this(System.GetUtcNow()) |
| 41 | + { |
| 42 | + |
| 43 | + } |
| 44 | + |
| 45 | + /// <summary> |
| 46 | + /// Creates an instance of the <see cref="ManualTimeProvider"/> with |
| 47 | + /// <paramref name="startDateTime"/> being the initial value returned by <see cref="GetUtcNow()"/>. |
| 48 | + /// </summary> |
| 49 | + /// <param name="startDateTime">The initial date and time <see cref="GetUtcNow()"/> will return.</param> |
| 50 | + public ManualTimeProvider(DateTimeOffset startDateTime) |
| 51 | + { |
| 52 | + utcNow = startDateTime; |
| 53 | + } |
| 54 | + |
| 55 | + /// <summary> |
| 56 | + /// Gets the current high-frequency value designed to measure small time intervals with high accuracy in the timer mechanism. |
| 57 | + /// </summary> |
| 58 | + /// <returns>A long integer representing the high-frequency counter value of the underlying timer mechanism. </returns> |
| 59 | + /// <remarks> |
| 60 | + /// This implementation bases timestamp on <see cref="DateTimeOffset.UtcTicks"/>, |
| 61 | + /// since the progression of time is represented by the date and time returned from <see cref="GetUtcNow()" />. |
| 62 | + /// </remarks> |
| 63 | + public override long GetTimestamp() => GetUtcNow().UtcTicks; |
| 64 | + |
| 65 | + /// <summary> |
| 66 | + /// Gets a <see cref="DateTimeOffset"/> value whose date and time are set to the current |
| 67 | + /// Coordinated Universal Time (UTC) date and time and whose offset is Zero, |
| 68 | + /// all according to this <see cref="ManualTimeProvider"/>'s notion of time. |
| 69 | + /// </summary> |
| 70 | + /// <remarks> |
| 71 | + /// To advance time, call <see cref="ForwardTime(TimeSpan)"/> or <see cref="SetUtcNow(DateTimeOffset)"/>. |
| 72 | + /// </remarks> |
| 73 | + public override DateTimeOffset GetUtcNow() => utcNow; |
| 74 | + |
| 75 | + /// <summary>Creates a new <see cref="ITimer"/> instance, using <see cref="TimeSpan"/> values to measure time intervals.</summary> |
| 76 | + /// <param name="callback"> |
| 77 | + /// A delegate representing a method to be executed when the timer fires. The method specified for callback should be reentrant, |
| 78 | + /// as it may be invoked simultaneously on two threads if the timer fires again before or while a previous callback is still being handled. |
| 79 | + /// </param> |
| 80 | + /// <param name="state">An object to be passed to the <paramref name="callback"/>. This may be null.</param> |
| 81 | + /// <param name="dueTime">The amount of time to delay before <paramref name="callback"/> is invoked. Specify <see cref="Timeout.InfiniteTimeSpan"/> to prevent the timer from starting. Specify <see cref="TimeSpan.Zero"/> to start the timer immediately.</param> |
| 82 | + /// <param name="period">The time interval between invocations of <paramref name="callback"/>. Specify <see cref="Timeout.InfiniteTimeSpan"/> to disable periodic signaling.</param> |
| 83 | + /// <returns> |
| 84 | + /// The newly created <see cref="ITimer"/> instance. |
| 85 | + /// </returns> |
| 86 | + /// <exception cref="ArgumentNullException"><paramref name="callback"/> is null.</exception> |
| 87 | + /// <exception cref="ArgumentOutOfRangeException">The number of milliseconds in the value of <paramref name="dueTime"/> or <paramref name="period"/> is negative and not equal to <see cref="Timeout.Infinite"/>, or is greater than <see cref="int.MaxValue"/>.</exception> |
| 88 | + /// <remarks> |
| 89 | + /// <para> |
| 90 | + /// The delegate specified by the callback parameter is invoked once after <paramref name="dueTime"/> elapses, and thereafter each time the <paramref name="period"/> time interval elapses. |
| 91 | + /// </para> |
| 92 | + /// <para> |
| 93 | + /// If <paramref name="dueTime"/> is zero, the callback is invoked immediately. If <paramref name="dueTime"/> is -1 milliseconds, <paramref name="callback"/> is not invoked; the timer is disabled, |
| 94 | + /// but can be re-enabled by calling the <see cref="ITimer.Change"/> method. |
| 95 | + /// </para> |
| 96 | + /// <para> |
| 97 | + /// If <paramref name="period"/> is 0 or -1 milliseconds and <paramref name="dueTime"/> is positive, <paramref name="callback"/> is invoked once; the periodic behavior of the timer is disabled, |
| 98 | + /// but can be re-enabled using the <see cref="ITimer.Change"/> method. |
| 99 | + /// </para> |
| 100 | + /// <para> |
| 101 | + /// The return <see cref="ITimer"/> instance will be implicitly rooted while the timer is still scheduled. |
| 102 | + /// </para> |
| 103 | + /// <para> |
| 104 | + /// <see cref="CreateTimer"/> captures the <see cref="ExecutionContext"/> and stores that with the <see cref="ITimer"/> for use in invoking <paramref name="callback"/> |
| 105 | + /// each time it's called. That capture can be suppressed with <see cref="ExecutionContext.SuppressFlow"/>. |
| 106 | + /// </para> |
| 107 | + /// <para> |
| 108 | + /// To advance time, call <see cref="ForwardTime(TimeSpan)"/> or <see cref="SetUtcNow(DateTimeOffset)"/>. |
| 109 | + /// </para> |
| 110 | + /// </remarks> |
| 111 | + public override ITimer CreateTimer(TimerCallback callback, object? state, TimeSpan dueTime, TimeSpan period) |
| 112 | + => new ManualTimer(callback, state, dueTime, period, this); |
| 113 | + |
| 114 | + /// <summary> |
| 115 | + /// Forward the date and time represented by <see cref="GetUtcNow()"/> |
| 116 | + /// by the specified <paramref name="time"/>, and triggers any |
| 117 | + /// scheduled items that are waiting for time to be forwarded. |
| 118 | + /// </summary> |
| 119 | + /// <param name="time">The span of time to forward <see cref="GetUtcNow()"/> with.</param> |
| 120 | + /// <exception cref="ArgumentException">If <paramref name="time"/> is negative or zero.</exception> |
| 121 | + public void ForwardTime(TimeSpan time) |
| 122 | + { |
| 123 | + if (time <= TimeSpan.Zero) |
| 124 | + throw new ArgumentException("The timespan to forward time by must be positive.", nameof(time)); |
| 125 | + |
| 126 | + SetUtcNow(utcNow + time); |
| 127 | + } |
| 128 | + |
| 129 | + /// <summary> |
| 130 | + /// Sets the date and time returned by <see cref="GetUtcNow()"/> to <paramref name="newUtcNew"/> and triggers any |
| 131 | + /// scheduled items that are waiting for time to be forwarded. |
| 132 | + /// </summary> |
| 133 | + /// <param name="newUtcNew">The new UtcNow time.</param> |
| 134 | + /// <exception cref="ArgumentException">If <paramref name="newUtcNew"/> is less than the value returned by <see cref="GetUtcNow()"/>.</exception> |
| 135 | + public void SetUtcNow(DateTimeOffset newUtcNew) |
| 136 | + { |
| 137 | + if (newUtcNew < utcNow) |
| 138 | + throw new ArgumentException("The new UtcNow must be greater than or equal to the current UtcNow.", nameof(newUtcNew)); |
| 139 | + |
| 140 | + while (utcNow <= newUtcNew && TryGetNext(newUtcNew) is ManualTimerScheduledCallback mtsc) |
| 141 | + { |
| 142 | + utcNow = mtsc.CallbackTime; |
| 143 | + mtsc.Timer.TimerElapsed(); |
| 144 | + } |
| 145 | + |
| 146 | + utcNow = newUtcNew; |
| 147 | + |
| 148 | + ManualTimerScheduledCallback? TryGetNext(DateTimeOffset targetUtcNow) |
| 149 | + { |
| 150 | + lock (futureCallbacks) |
| 151 | + { |
| 152 | + if (futureCallbacks.Count > 0 && futureCallbacks[0].CallbackTime <= targetUtcNow) |
| 153 | + { |
| 154 | + var callback = futureCallbacks[0]; |
| 155 | + futureCallbacks.RemoveAt(0); |
| 156 | + return callback; |
| 157 | + } |
| 158 | + } |
| 159 | + |
| 160 | + return null; |
| 161 | + } |
| 162 | + } |
| 163 | + |
| 164 | + private void ScheduleCallback(ManualTimer timer, TimeSpan waitTime) |
| 165 | + { |
| 166 | + lock (futureCallbacks) |
| 167 | + { |
| 168 | + var mtsc = new ManualTimerScheduledCallback(timer, utcNow + waitTime); |
| 169 | + var insertPosition = futureCallbacks.FindIndex(x => x.CallbackTime > mtsc.CallbackTime); |
| 170 | + |
| 171 | + if (insertPosition == -1) |
| 172 | + futureCallbacks.Add(mtsc); |
| 173 | + else |
| 174 | + { |
| 175 | + futureCallbacks.Insert(insertPosition, mtsc); |
| 176 | + } |
| 177 | + } |
| 178 | + } |
| 179 | + |
| 180 | + private void RemoveCallback(ManualTimer timer) |
| 181 | + { |
| 182 | + lock (futureCallbacks) |
| 183 | + { |
| 184 | + var existingIndexOf = futureCallbacks.FindIndex(0, x => ReferenceEquals(x.Timer, timer)); |
| 185 | + if (existingIndexOf >= 0) |
| 186 | + futureCallbacks.RemoveAt(existingIndexOf); |
| 187 | + } |
| 188 | + } |
| 189 | + |
| 190 | + private readonly struct ManualTimerScheduledCallback : |
| 191 | + IEqualityComparer<ManualTimerScheduledCallback>, |
| 192 | + IComparable<ManualTimerScheduledCallback> |
| 193 | + { |
| 194 | + public readonly ManualTimer Timer { get; } |
| 195 | + public readonly DateTimeOffset CallbackTime { get; } |
| 196 | + |
| 197 | + public ManualTimerScheduledCallback(ManualTimer timer, DateTimeOffset callbackTime) |
| 198 | + { |
| 199 | + Timer = timer; |
| 200 | + CallbackTime = callbackTime; |
| 201 | + } |
| 202 | + |
| 203 | + public readonly bool Equals(ManualTimerScheduledCallback x, ManualTimerScheduledCallback y) |
| 204 | + => ReferenceEquals(x.Timer, y.Timer); |
| 205 | + |
| 206 | + public readonly int GetHashCode(ManualTimerScheduledCallback obj) |
| 207 | + => Timer.GetHashCode(); |
| 208 | + |
| 209 | + public readonly int CompareTo(ManualTimerScheduledCallback other) |
| 210 | + => Comparer<DateTimeOffset>.Default.Compare(CallbackTime, other.CallbackTime); |
| 211 | + } |
| 212 | + |
| 213 | + private sealed class ManualTimer : ITimer |
| 214 | + { |
| 215 | + private readonly ManualTimeProvider owner; |
| 216 | + private bool isDisposed; |
| 217 | + private bool running; |
| 218 | + |
| 219 | + private TimeSpan currentDueTime; |
| 220 | + private TimeSpan currentPeriod; |
| 221 | + private object? state; |
| 222 | + private TimerCallback? callback; |
| 223 | + |
| 224 | + public ManualTimer(TimerCallback callback, object? state, TimeSpan dueTime, TimeSpan period, ManualTimeProvider owner) |
| 225 | + { |
| 226 | + ValidateTimeSpanRange(dueTime); |
| 227 | + ValidateTimeSpanRange(period); |
| 228 | + |
| 229 | + this.callback = callback; |
| 230 | + this.state = state; |
| 231 | + currentDueTime = dueTime; |
| 232 | + currentPeriod = period; |
| 233 | + this.owner = owner; |
| 234 | + |
| 235 | + if (currentDueTime != Timeout.InfiniteTimeSpan) |
| 236 | + ScheduleCallback(dueTime); |
| 237 | + } |
| 238 | + |
| 239 | + public bool Change(TimeSpan dueTime, TimeSpan period) |
| 240 | + { |
| 241 | + ValidateTimeSpanRange(dueTime); |
| 242 | + ValidateTimeSpanRange(period); |
| 243 | + |
| 244 | + if (running) |
| 245 | + owner.RemoveCallback(this); |
| 246 | + |
| 247 | + currentDueTime = dueTime; |
| 248 | + currentPeriod = period; |
| 249 | + |
| 250 | + if (currentDueTime != Timeout.InfiniteTimeSpan) |
| 251 | + ScheduleCallback(dueTime); |
| 252 | + |
| 253 | + return true; |
| 254 | + } |
| 255 | + |
| 256 | + public void Dispose() |
| 257 | + { |
| 258 | + if (isDisposed) |
| 259 | + return; |
| 260 | + |
| 261 | + isDisposed = true; |
| 262 | + |
| 263 | + if (running) |
| 264 | + owner.RemoveCallback(this); |
| 265 | + |
| 266 | + callback = null; |
| 267 | + state = null; |
| 268 | + } |
| 269 | + |
| 270 | + public ValueTask DisposeAsync() |
| 271 | + { |
| 272 | + Dispose(); |
| 273 | +#if NETSTANDARD2_0 |
| 274 | + return new ValueTask(Task.CompletedTask); |
| 275 | +#else |
| 276 | + return ValueTask.CompletedTask; |
| 277 | +#endif |
| 278 | + } |
| 279 | + |
| 280 | + internal void TimerElapsed() |
| 281 | + { |
| 282 | + if (isDisposed) |
| 283 | + return; |
| 284 | + |
| 285 | + running = false; |
| 286 | + callback?.Invoke(state); |
| 287 | + |
| 288 | + if (currentPeriod != Timeout.InfiniteTimeSpan) |
| 289 | + ScheduleCallback(currentPeriod); |
| 290 | + } |
| 291 | + |
| 292 | + private void ScheduleCallback(TimeSpan waitTime) |
| 293 | + { |
| 294 | + if (isDisposed) |
| 295 | + return; |
| 296 | + |
| 297 | + running = true; |
| 298 | + owner.ScheduleCallback(this, waitTime); |
| 299 | + } |
| 300 | + |
| 301 | + private static void ValidateTimeSpanRange(TimeSpan time, [CallerArgumentExpression("time")] string? parameter = null) |
| 302 | + { |
| 303 | + long tm = (long)time.TotalMilliseconds; |
| 304 | + if (tm < -1) |
| 305 | + throw new ArgumentOutOfRangeException(parameter, $"{parameter}.TotalMilliseconds must be greater than -1."); |
| 306 | + |
| 307 | + if (tm > MaxSupportedTimeout) |
| 308 | + throw new ArgumentOutOfRangeException(parameter, $"{parameter}.TotalMilliseconds must be less than than {MaxSupportedTimeout}."); |
| 309 | + } |
| 310 | + } |
| 311 | +} |
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