Use higher time resolution when available in os.nim (#7709)

lib/posix/posix.nim

@@ -82,6 +82,14 @@ const
 # Special types
 type Sighandler = proc (a: cint) {.noconv.}
 
+const StatHasNanoseconds* = defined(linux) or defined(freebsd) or
+    defined(openbsd) or defined(dragonfly) ## \
+  ## Boolean flag that indicates if the system supports nanosecond time
+  ## resolution in the fields of ``Stat``. Note that the nanosecond based fields
+  ## (``Stat.st_atim``, ``Stat.st_mtim`` and ``Stat.st_ctim``) can be accessed
+  ## without checking this flag, because this module defines fallback procs
+  ## when they are not available.
+
 # Platform specific stuff
 
 when defined(linux) and defined(amd64):
@@ -92,9 +100,9 @@ else:
 # There used to be this name in posix.nim a long time ago, not sure why!
 {.deprecated: [cSIG_HOLD: SIG_HOLD].}
 
-when not defined(macosx) and not defined(android):
+when StatHasNanoseconds:
   proc st_atime*(s: Stat): Time {.inline.} =
-    ## Second-granularity time of last access
+    ## Second-granularity time of last access.
     result = s.st_atim.tv_sec
   proc st_mtime*(s: Stat): Time {.inline.} =
     ## Second-granularity time of last data modification.
@@ -102,6 +110,16 @@ when not defined(macosx) and not defined(android):
   proc st_ctime*(s: Stat): Time {.inline.} =
     ## Second-granularity time of last status change.
     result = s.st_ctim.tv_sec
+else:
+  proc st_atim*(s: Stat): TimeSpec {.inline.} =
+    ## Nanosecond-granularity time of last access.
+    result.tv_sec = s.st_atime
+  proc st_mtim*(s: Stat): TimeSpec {.inline.} =
+    ## Nanosecond-granularity time of last data modification.
+    result.tv_sec = s.st_mtime
+  proc st_ctim*(s: Stat): TimeSpec {.inline.} =
+    ## Nanosecond-granularity time of last data modification.
+    result.tv_sec = s.st_ctime
 
 when hasAioH:
   proc aio_cancel*(a1: cint, a2: ptr Taiocb): cint {.importc, header: "<aio.h>".}

lib/posix/posix_other.nim

@@ -215,14 +215,14 @@ type
                           ## For a typed memory object, the length in bytes.
                           ## For other file types, the use of this field is
                           ## unspecified.
-    when defined(macosx) or defined(android):
-      st_atime*: Time     ## Time of last access.
-      st_mtime*: Time     ## Time of last data modification.
-      st_ctime*: Time     ## Time of last status change.
-    else:
+    when StatHasNanoseconds:
       st_atim*: Timespec  ## Time of last access.
       st_mtim*: Timespec  ## Time of last data modification.
       st_ctim*: Timespec  ## Time of last status change.
+    else:
+      st_atime*: Time     ## Time of last access.
+      st_mtime*: Time     ## Time of last data modification.
+      st_ctime*: Time     ## Time of last status change.
     st_blksize*: Blksize  ## A file system-specific preferred I/O block size
                           ## for this object. In some file system types, this
                           ## may vary from file to file.

lib/pure/os.nim

@@ -23,6 +23,10 @@ when defined(windows):
   import winlean
 elif defined(posix):
   import posix
+
+  proc toTime(ts: Timespec): times.Time {.inline.} =
+    result = initTime(ts.tv_sec.int64, ts.tv_nsec.int)
+
 else:
   {.error: "OS module not ported to your operating system!".}
 
@@ -186,7 +190,7 @@ proc getLastModificationTime*(file: string): times.Time {.rtl, extern: "nos$1".}
   when defined(posix):
     var res: Stat
     if stat(file, res) < 0'i32: raiseOSError(osLastError())
-    return fromUnix(res.st_mtime.int64)
+    result = res.st_mtim.toTime
   else:
     var f: WIN32_FIND_DATA
     var h = findFirstFile(file, f)
@@ -199,7 +203,7 @@ proc getLastAccessTime*(file: string): times.Time {.rtl, extern: "nos$1".} =
   when defined(posix):
     var res: Stat
     if stat(file, res) < 0'i32: raiseOSError(osLastError())
-    return fromUnix(res.st_atime.int64)
+    result = res.st_atim.toTime
   else:
     var f: WIN32_FIND_DATA
     var h = findFirstFile(file, f)
@@ -216,7 +220,7 @@ proc getCreationTime*(file: string): times.Time {.rtl, extern: "nos$1".} =
   when defined(posix):
     var res: Stat
     if stat(file, res) < 0'i32: raiseOSError(osLastError())
-    return fromUnix(res.st_ctime.int64)
+    result = res.st_ctim.toTime
   else:
     var f: WIN32_FIND_DATA
     var h = findFirstFile(file, f)
@@ -228,10 +232,13 @@ proc fileNewer*(a, b: string): bool {.rtl, extern: "nos$1".} =
   ## Returns true if the file `a` is newer than file `b`, i.e. if `a`'s
   ## modification time is later than `b`'s.
   when defined(posix):
-    result = getLastModificationTime(a) - getLastModificationTime(b) >= DurationZero
-    # Posix's resolution sucks so, we use '>=' for posix.
+    # If we don't have access to nanosecond resolution, use '>='
+    when not StatHasNanoseconds:  
+      result = getLastModificationTime(a) >= getLastModificationTime(b)
+    else:
+      result = getLastModificationTime(a) > getLastModificationTime(b)
   else:
-    result = getLastModificationTime(a) - getLastModificationTime(b) > DurationZero
+    result = getLastModificationTime(a) > getLastModificationTime(b)
 
 proc getCurrentDir*(): string {.rtl, extern: "nos$1", tags: [].} =
   ## Returns the `current working directory`:idx:.
@@ -1494,7 +1501,7 @@ type
 
 template rawToFormalFileInfo(rawInfo, path, formalInfo): untyped =
   ## Transforms the native file info structure into the one nim uses.
-  ## 'rawInfo' is either a 'TBY_HANDLE_FILE_INFORMATION' structure on Windows,
+  ## 'rawInfo' is either a 'BY_HANDLE_FILE_INFORMATION' structure on Windows,
   ## or a 'Stat' structure on posix
   when defined(Windows):
     template merge(a, b): untyped = a or (b shl 32)
@@ -1520,7 +1527,6 @@ template rawToFormalFileInfo(rawInfo, path, formalInfo): untyped =
     if (rawInfo.dwFileAttributes and FILE_ATTRIBUTE_REPARSE_POINT) != 0'i32:
       formalInfo.kind = succ(result.kind)
 
-
   else:
     template checkAndIncludeMode(rawMode, formalMode: untyped) =
       if (rawInfo.st_mode and rawMode) != 0'i32:
@@ -1528,9 +1534,9 @@ template rawToFormalFileInfo(rawInfo, path, formalInfo): untyped =
     formalInfo.id = (rawInfo.st_dev, rawInfo.st_ino)
     formalInfo.size = rawInfo.st_size
     formalInfo.linkCount = rawInfo.st_Nlink.BiggestInt
-    formalInfo.lastAccessTime = fromUnix(rawInfo.st_atime.int64)
-    formalInfo.lastWriteTime = fromUnix(rawInfo.st_mtime.int64)
-    formalInfo.creationTime = fromUnix(rawInfo.st_ctime.int64)
+    formalInfo.lastAccessTime = rawInfo.st_atim.toTime
+    formalInfo.lastWriteTime = rawInfo.st_mtim.toTime
+    formalInfo.creationTime = rawInfo.st_ctim.toTime
 
     result.permissions = {}
     checkAndIncludeMode(S_IRUSR, fpUserRead)
@@ -1644,7 +1650,9 @@ proc setLastModificationTime*(file: string, t: times.Time) =
   ## an error.
   when defined(posix):
     let unixt = posix.Time(t.toUnix)
-    var timevals = [Timeval(tv_sec: unixt), Timeval(tv_sec: unixt)] # [last access, last modification]
+    let micro = convert(Nanoseconds, Microseconds, t.nanosecond)
+    var timevals = [Timeval(tv_sec: unixt, tv_usec: micro),
+      Timeval(tv_sec: unixt, tv_usec: micro)] # [last access, last modification]
     if utimes(file, timevals.addr) != 0: raiseOSError(osLastError())
   else:
     let h = openHandle(path = file, writeAccess = true)

tests/stdlib/tos.nim

@@ -42,6 +42,7 @@ Raises
 true
 true
 true
+true
 '''
 """
 # test os path creation, iteration, and deletion
@@ -129,3 +130,12 @@ echo fileExists("../dest/a/b/file.txt")
 
 echo fileExists("../dest/a/b/c/fileC.txt")
 removeDir("../dest")
+
+# Test get/set modification times
+# Should support at least microsecond resolution
+import times
+let tm = fromUnix(0) + 100.microseconds
+writeFile("a", "")
+setLastModificationTime("a", tm)
+echo getLastModificationTime("a") == tm
+removeFile("a")