Merge remote-tracking branch 'copiousfreetime/process-clock_getres' into process-clock_getres

Author: chrisseaton

src/main/c/truffleposix/truffleposix.c

@@ -399,6 +399,15 @@ int64_t truffleposix_clock_gettime(int clock) {
   }
   return ((int64_t) timespec.tv_sec * 1000000000) + (int64_t) timespec.tv_nsec;
 }
+
+int64_t truffleposix_clock_getres(int clock) {
+  struct timespec timespec;
+  int ret = clock_getres((clockid_t) clock, &timespec);
+  if (ret != 0) {
+    return 0;
+  }
+  return ((int64_t) timespec.tv_sec * 1000000000) + (int64_t) timespec.tv_nsec;
+}
 #endif
 
 #define CHECK(call, label) if ((error = call) != 0) { perror(#call); goto label; }

src/main/ruby/core/posix.rb

@@ -169,6 +169,7 @@ def self.attach_function_eagerly(native_name, argument_types, return_type,
   attach_function :chmod, [:string, :mode_t], :int
   attach_function :chown, [:string, :uid_t, :gid_t], :int
   attach_function :chroot, [:string], :int
+  attach_function :truffleposix_clock_getres, [:int], :int64_t, LIBTRUFFLEPOSIX
   attach_function :truffleposix_clock_gettime, [:int], :int64_t, LIBTRUFFLEPOSIX
   attach_function :close, [:int], :int
   attach_function :closedir, [:pointer], :int

src/main/ruby/core/process.rb

@@ -115,6 +115,40 @@ def self.time
     const_set(key.substring(section.size, key.length), value)
   end
 
+  def self.clock_getres(id, unit=:float_second)
+    res = case id
+    when :MACH_ABSOLUTE_TIME_BASED_CLOCK_MONOTONIC,
+         CLOCK_MONOTONIC
+      1
+    when :GETTIMEOFDAY_BASED_CLOCK_REALTIME,
+         :GETRUSAGE_BASED_CLOCK_PROCESS_CPUTIME_ID,
+         :CLOCK_BASED_CLOCK_PROCESS_CPUTIME_ID
+      1_000
+    when CLOCK_REALTIME
+      1_000_000
+    when :TIMES_BASED_CLOCK_MONOTONIC,
+         :TIMES_BASED_CLOCK_PROCESS_CPUTIME_ID
+      10_000_000
+    when :TIME_BASED_CLOCK_REALTIME
+      1_000_000_000
+    when Symbol
+      raise Errno::EINVAL
+    else
+      _res = Truffle::POSIX.truffleposix_clock_getres(id)
+      if _res == 0 then
+        Errno.handle
+      else
+        _res
+      end
+    end
+
+    if :hertz == unit then
+      1.0 / nanoseconds_to_unit(res,:float_second)
+    else
+      nanoseconds_to_unit(res,unit)
+    end
+  end
+
   def self.clock_gettime(id, unit=:float_second)
     if id.is_a?(Symbol)
       id = case id
@@ -143,21 +177,25 @@ def self.clock_gettime(id, unit=:float_second)
       Errno.handle if time == 0
     end
 
+    nanoseconds_to_unit(time, unit)
+  end
+
+  def self.nanoseconds_to_unit(nanoseconds, unit)
     case unit
     when :nanosecond
-      time
+      nanoseconds
     when :microsecond
-      time / 1_000
+      nanoseconds / 1_000
     when :millisecond
-      time / 1_000_000
+      nanoseconds / 1_000_000
     when :second
-      time / 1_000_000_000
+      nanoseconds / 1_000_000_000
     when :float_microsecond
-      time / 1e3
+      nanoseconds / 1e3
     when :float_millisecond
-      time / 1e6
+      nanoseconds / 1e6
     when :float_second, nil
-      time / 1e9
+      nanoseconds / 1e9
     else
       raise ArgumentError, "unexpected unit: #{unit}"
     end