Using FUTIMENS instead of FUTIMES (#34271)

* test added

* rearranging order for if statements

* reducing thread sleep time and reverting millisecond test change

* adding comment

* removing comment, adding tick equality check, failing if not able to create file with non-zero nano or milli second

* correcting test for hfs system

* NanoSeconds -> Nanoseconds, Millisec -> milliseconds
HFs assert converted to false

src/Native/Unix/System.Native/pal_io.c

@@ -1314,22 +1314,21 @@ int32_t SystemNative_CopyFile(intptr_t sourceFd, intptr_t destinationFd)
     while ((ret = fstat_(inFd, &sourceStat)) < 0 && errno == EINTR);
     if (ret == 0)
     {
-#if HAVE_FUTIMES
-        struct timeval origTimes[2];
-        origTimes[0].tv_sec = sourceStat.st_atime;
-        origTimes[0].tv_usec = ST_ATIME_NSEC(&sourceStat) / 1000;
-        origTimes[1].tv_sec = sourceStat.st_mtime;
-        origTimes[1].tv_usec = ST_MTIME_NSEC(&sourceStat) / 1000;
-        while ((ret = futimes(outFd, origTimes)) < 0 && errno == EINTR);
-#elif HAVE_FUTIMENS
-        // futimes is not a POSIX function, and not available on Android,
-        // but futimens is
+#if HAVE_FUTIMENS
+        // futimens is prefered because it has a higher resolution.
         struct timespec origTimes[2];
         origTimes[0].tv_sec = (time_t)sourceStat.st_atime;
         origTimes[0].tv_nsec = ST_ATIME_NSEC(&sourceStat);
         origTimes[1].tv_sec = (time_t)sourceStat.st_mtime;
         origTimes[1].tv_nsec = ST_MTIME_NSEC(&sourceStat);
         while ((ret = futimens(outFd, origTimes)) < 0 && errno == EINTR);
+#elif HAVE_FUTIMES
+        struct timeval origTimes[2];
+        origTimes[0].tv_sec = sourceStat.st_atime;
+        origTimes[0].tv_usec = ST_ATIME_NSEC(&sourceStat) / 1000;
+        origTimes[1].tv_sec = sourceStat.st_mtime;
+        origTimes[1].tv_usec = ST_MTIME_NSEC(&sourceStat) / 1000;
+        while ((ret = futimes(outFd, origTimes)) < 0 && errno == EINTR);
 #endif
     }
     if (ret != 0)

src/System.IO.FileSystem/tests/FileInfo/GetSetTimes.cs

@@ -18,6 +18,48 @@ namespace System.IO.Tests
             return new FileInfo(path);
         }
 
+        private static bool HasNonZeroNanoseconds(DateTime dt) => dt.Ticks % 10 != 0;
+        
+        public FileInfo GetNonZeroMilliseconds()
+        {
+            FileInfo fileinfo = new FileInfo(GetTestFilePath());
+            for (int i = 0; i < 5; i++)
+            {
+                fileinfo.Create().Dispose();
+                if (fileinfo.LastWriteTime.Millisecond != 0)
+                    break;
+
+                // This case should only happen 1/1000 times, unless the OS/Filesystem does
+                // not support millisecond granularity.
+
+                // If it's 1/1000, or low granularity, this may help:
+                Thread.Sleep(1234);
+            }
+
+            Assert.NotEqual(0, fileinfo.LastWriteTime.Millisecond);
+            return fileinfo;
+        }
+
+        public FileInfo GetNonZeroNanoseconds()
+        {
+            FileInfo fileinfo = new FileInfo(GetTestFilePath());
+            for (int i = 0; i < 5; i++)
+            {
+                fileinfo.Create().Dispose();
+                if (HasNonZeroNanoseconds(fileinfo.LastWriteTime))
+                    break;
+
+                // This case should only happen 1/10 times, unless the OS/Filesystem does
+                // not support nanosecond granularity.
+
+                // If it's 1/10, or low granularity, this may help:
+                Thread.Sleep(123);
+            }
+            
+            Assert.True(HasNonZeroNanoseconds(fileinfo.LastWriteTime), "Tests failed to create a file with non-zero nanoseconds.");
+            return fileinfo;
+        }
+
         public override FileInfo GetMissingItem() => new FileInfo(GetTestFilePath());
 
         public override string GetItemPath(FileInfo item) => item.FullName;
@@ -70,25 +112,64 @@ namespace System.IO.Tests
         [ConditionalFact(nameof(isNotHFS))]
         public void CopyToMillisecondPresent()
         {
-            FileInfo input = new FileInfo(GetTestFilePath());
-            for (int i = 0; i < 5; i++)
-            {
-                input.Create().Dispose();
-                if (input.LastWriteTime.Millisecond != 0)
-                    break;
-
-                // This case should only happen 1/1000 times, unless the OS/Filesystem does
-                // not support millisecond granularity.
-
-                // If it's 1/1000, or low granularity, this may help:
-                Thread.Sleep(1234);
-            }
-
+            FileInfo input = GetNonZeroMilliseconds();
             FileInfo output = new FileInfo(Path.Combine(GetTestFilePath(), input.Name));
+
             Assert.Equal(0, output.LastWriteTime.Millisecond);
             output.Directory.Create();
             output = input.CopyTo(output.FullName, true);
-            Assert.NotEqual(0, input.LastWriteTime.Millisecond);
+
+            Assert.Equal(input.LastWriteTime.Millisecond, output.LastWriteTime.Millisecond);
+            Assert.NotEqual(0, output.LastWriteTime.Millisecond);
+        }
+
+        [ConditionalFact(nameof(isNotHFS))]
+        public void CopyToNanosecondsPresent()
+        {
+            FileInfo input = GetNonZeroNanoseconds();
+            FileInfo output = new FileInfo(Path.Combine(GetTestFilePath(), input.Name));
+
+            output.Directory.Create();
+            output = input.CopyTo(output.FullName, true);
+
+            Assert.Equal(input.LastWriteTime.Ticks, output.LastWriteTime.Ticks);
+            Assert.True(HasNonZeroNanoseconds(output.LastWriteTime));
+        }
+
+        [ConditionalFact(nameof(isHFS))]
+        public void CopyToNanosecondsPresent_HFS()
+        {
+            FileInfo input = new FileInfo(GetTestFilePath());
+            input.Create().Dispose();
+            FileInfo output = new FileInfo(Path.Combine(GetTestFilePath(), input.Name));
+
+            output.Directory.Create();
+            output = input.CopyTo(output.FullName, true);
+
+            Assert.Equal(input.LastWriteTime.Ticks, output.LastWriteTime.Ticks);
+            Assert.False(HasNonZeroNanoseconds(output.LastWriteTime));
+        }
+
+        [ConditionalFact(nameof(isHFS))]
+        public void MoveToMillisecondPresent_HFS()
+        {
+            FileInfo input = new FileInfo(GetTestFilePath());
+            input.Create().Dispose();
+
+            string dest = Path.Combine(input.DirectoryName, GetTestFileName());
+            input.MoveTo(dest);
+            FileInfo output = new FileInfo(dest);
+            Assert.Equal(0, output.LastWriteTime.Millisecond);
+        }
+
+        [ConditionalFact(nameof(isNotHFS))]
+        public void MoveToMillisecondPresent()
+        {
+            FileInfo input = GetNonZeroMilliseconds();
+            string dest = Path.Combine(input.DirectoryName, GetTestFileName());
+
+            input.MoveTo(dest);
+            FileInfo output = new FileInfo(dest);
             Assert.NotEqual(0, output.LastWriteTime.Millisecond);
         }
 
@@ -100,61 +181,10 @@ namespace System.IO.Tests
             FileInfo output = new FileInfo(Path.Combine(GetTestFilePath(), input.Name));
             output.Directory.Create();
             output = input.CopyTo(output.FullName, true);
-            Assert.Equal(0, input.LastWriteTime.Millisecond);
+            Assert.Equal(input.LastWriteTime.Millisecond, output.LastWriteTime.Millisecond);
             Assert.Equal(0, output.LastWriteTime.Millisecond);
         }
 
-        [Fact]
-        public void CopyToMillisecondPresent()
-        {
-            FileInfo input = new FileInfo(Path.Combine(TestDirectory, GetTestFileName()));
-            input.Create().Dispose();
-
-            string driveFormat = new DriveInfo(input.DirectoryName).DriveFormat;
-            if (!driveFormat.Equals(HFS, StringComparison.InvariantCultureIgnoreCase))
-            {
-                for (int i = 0; i < 5; i++)
-                {
-                    if (input.LastWriteTime.Millisecond != 0)
-                        break;
-
-                    // This case should only happen 1/1000 times, unless the OS/Filesystem does
-                    // not support millisecond granularity.
-
-                    // If it's 1/1000, or low granularity, this may help:
-                    Thread.Sleep(1234);
-                    input = new FileInfo(Path.Combine(TestDirectory, GetTestFileName()));
-                    input.Create().Dispose();
-                }
-
-                FileInfo output = new FileInfo(Path.Combine(TestDirectory, GetTestFileName(), input.Name));
-                Assert.Equal(0, output.LastWriteTime.Millisecond);
-                output.Directory.Create();
-                output = input.CopyTo(output.FullName, true);
-
-                Assert.NotEqual(0, input.LastWriteTime.Millisecond);
-                Assert.NotEqual(0, output.LastWriteTime.Millisecond);
-            }
-        }
-
-        [Fact]
-        [PlatformSpecific(TestPlatforms.OSX)]
-        public void CopyToMillisecondPresent_HFS()
-        {
-            FileInfo input = new FileInfo(Path.Combine(TestDirectory, GetTestFileName()));
-            input.Create().Dispose();
-            FileInfo output = new FileInfo(Path.Combine(TestDirectory, GetTestFileName(), input.Name));
-
-            string driveFormat = new DriveInfo(input.DirectoryName).DriveFormat;
-            if (driveFormat.Equals(HFS, StringComparison.InvariantCultureIgnoreCase))
-            {             
-                output.Directory.Create();
-                output = input.CopyTo(output.FullName, true);
-                Assert.Equal(0, input.LastWriteTime.Millisecond);
-                Assert.Equal(0, output.LastWriteTime.Millisecond);
-            }
-        }
-
         [Fact]
         public void DeleteAfterEnumerate_TimesStillSet()
         {
@@ -190,8 +220,7 @@ namespace System.IO.Tests
             Assert.InRange(fi.CreationTimeUtc, before, fi.LastWriteTimeUtc);
         }
 
-
-        [Fact]
+        [ConditionalFact(typeof(PlatformDetection), nameof(PlatformDetection.IsNotInAppContainer))] // Can't read root in appcontainer
         [PlatformSpecific(TestPlatforms.Windows)]
         public void PageFileHasTimes()
         {