Initial checkin of gRPC to third_party/

third_party/grpc/src/csharp/Grpc.Core/Internal/Timespec.cs

+#region Copyright notice and license
+// Copyright 2015-2016, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+using System;
+using System.Runtime.InteropServices;
+using System.Threading;
+
+using Grpc.Core.Utils;
+
+namespace Grpc.Core.Internal
+{
+    /// <summary>
+    /// gpr_timespec from grpc/support/time.h
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential)]
+    internal struct Timespec
+    {
+        const long NanosPerSecond = 1000 * 1000 * 1000;
+        const long NanosPerTick = 100;
+        const long TicksPerSecond = NanosPerSecond / NanosPerTick;
+
+        static readonly NativeMethods Native = NativeMethods.Get();
+        static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
+
+        public Timespec(long tv_sec, int tv_nsec) : this(tv_sec, tv_nsec, GPRClockType.Realtime)
+        {
+        }
+
+        public Timespec(long tv_sec, int tv_nsec, GPRClockType clock_type)
+        {
+            this.tv_sec = tv_sec;
+            this.tv_nsec = tv_nsec;
+            this.clock_type = clock_type;
+        }
+
+        private long tv_sec;
+        private int tv_nsec;
+        private GPRClockType clock_type;
+
+        /// <summary>
+        /// Timespec a long time in the future.
+        /// </summary>
+        public static Timespec InfFuture
+        {
+            get
+            {
+                return Native.gprsharp_inf_future(GPRClockType.Realtime);
+            }
+        }
+
+        /// <summary>
+        /// Timespec a long time in the past.
+        /// </summary>
+        public static Timespec InfPast
+        {
+            get
+            {
+                return Native.gprsharp_inf_past(GPRClockType.Realtime);
+            }
+        }
+
+        /// <summary>
+        /// Return Timespec representing the current time.
+        /// </summary>
+        public static Timespec Now
+        {
+            get
+            {
+                return Native.gprsharp_now(GPRClockType.Realtime);
+            }
+        }
+
+        /// <summary>
+        /// Seconds since unix epoch.
+        /// </summary>
+        public long TimevalSeconds
+        {
+            get
+            {
+                return tv_sec;
+            }
+        }
+
+        /// <summary>
+        /// The nanoseconds part of timeval.
+        /// </summary>
+        public int TimevalNanos
+        {
+            get
+            {
+                return tv_nsec;
+            }
+        }
+
+        /// <summary>
+        /// Converts the timespec to desired clock type.
+        /// </summary>
+        public Timespec ToClockType(GPRClockType targetClock)
+        {
+            return Native.gprsharp_convert_clock_type(this, targetClock);
+        }
+            
+        /// <summary>
+        /// Converts Timespec to DateTime.
+        /// Timespec needs to be of type GPRClockType.Realtime and needs to represent a legal value.
+        /// DateTime has lower resolution (100ns), so rounding can occurs.
+        /// Value are always rounded up to the nearest DateTime value in the future.
+        /// 
+        /// For Timespec.InfFuture or if timespec is after the largest representable DateTime, DateTime.MaxValue is returned.
+        /// For Timespec.InfPast or if timespec is before the lowest representable DateTime, DateTime.MinValue is returned.
+        /// 
+        /// Unless DateTime.MaxValue or DateTime.MinValue is returned, the resulting DateTime is always in UTC
+        /// (DateTimeKind.Utc)
+        /// </summary>
+        public DateTime ToDateTime()
+        {
+            GrpcPreconditions.CheckState(tv_nsec >= 0 && tv_nsec < NanosPerSecond);
+            GrpcPreconditions.CheckState(clock_type == GPRClockType.Realtime);
+
+            // fast path for InfFuture
+            if (this.Equals(InfFuture))
+            {
+                return DateTime.MaxValue;
+            }
+
+            // fast path for InfPast
+            if (this.Equals(InfPast))
+            {
+                return DateTime.MinValue;
+            }
+
+            try
+            {
+                // convert nanos to ticks, round up to the nearest tick
+                long ticksFromNanos = tv_nsec / NanosPerTick + ((tv_nsec % NanosPerTick != 0) ? 1 : 0);
+                long ticksTotal = checked(tv_sec * TicksPerSecond + ticksFromNanos);
+                return UnixEpoch.AddTicks(ticksTotal);
+            }
+            catch (OverflowException)
+            {
+                // ticks out of long range
+                return tv_sec > 0 ? DateTime.MaxValue : DateTime.MinValue;
+            }
+            catch (ArgumentOutOfRangeException)
+            {
+                // resulting date time would be larger than MaxValue
+                return tv_sec > 0 ? DateTime.MaxValue : DateTime.MinValue;
+            }
+        }
+            
+        /// <summary>
+        /// Creates DateTime to Timespec.
+        /// DateTime has to be in UTC (DateTimeKind.Utc) unless it's DateTime.MaxValue or DateTime.MinValue.
+        /// For DateTime.MaxValue of date time after the largest representable Timespec, Timespec.InfFuture is returned.
+        /// For DateTime.MinValue of date time before the lowest representable Timespec, Timespec.InfPast is returned.
+        /// </summary>
+        /// <returns>The date time.</returns>
+        /// <param name="dateTime">Date time.</param>
+        public static Timespec FromDateTime(DateTime dateTime)
+        {
+            if (dateTime == DateTime.MaxValue)
+            {
+                return Timespec.InfFuture;
+            }
+
+            if (dateTime == DateTime.MinValue)
+            {
+                return Timespec.InfPast;
+            }
+
+            GrpcPreconditions.CheckArgument(dateTime.Kind == DateTimeKind.Utc, "dateTime needs of kind DateTimeKind.Utc or be equal to DateTime.MaxValue or DateTime.MinValue.");
+
+            try
+            {
+                TimeSpan timeSpan = dateTime - UnixEpoch;
+                long ticks = timeSpan.Ticks;
+
+                long seconds = ticks / TicksPerSecond;  
+                int nanos = (int)((ticks % TicksPerSecond) * NanosPerTick);
+                if (nanos < 0) 
+                {
+                    // correct the result based on C# modulo semantics for negative dividend
+                    seconds--;
+                    nanos += (int)NanosPerSecond;
+                }
+                return new Timespec(seconds, nanos);
+            }
+            catch (ArgumentOutOfRangeException)
+            {
+                return dateTime > UnixEpoch ? Timespec.InfFuture : Timespec.InfPast;
+            }
+        }
+
+        /// <summary>
+        /// Gets current timestamp using <c>GPRClockType.Precise</c>.
+        /// Only available internally because core needs to be compiled with 
+        /// GRPC_TIMERS_RDTSC support for this to use RDTSC.
+        /// </summary>
+        internal static Timespec PreciseNow
+        {
+            get
+            {
+                return Native.gprsharp_now(GPRClockType.Precise);
+            }
+        }
+
+        internal static int NativeSize
+        {
+            get
+            {
+                return Native.gprsharp_sizeof_timespec();
+            }
+        }
+    }
+}