From f6d25c091261d4a4ed031f24b0df6d4a172cec56 Mon Sep 17 00:00:00 2001
Message-Id: <f6d25c091261d4a4ed031f24b0df6d4a172cec56.1363620073.git.brad.king@kitware.com>
From: Brad King <brad.king@kitware.com>
Date: Mon, 18 Mar 2013 11:19:47 -0400
Subject: [PATCH] Touch with better than 1s resolution if possible

Use utimensat if available.  Skip this capability during bootstrap.
---
 Source/kwsys/CMakeLists.txt            |    4 +++-
 Source/kwsys/SystemTools.cxx           |    8 ++++++++
 Source/kwsys/kwsysPlatformTestsCXX.cxx |   10 ++++++++++
 bootstrap                              |    1 +
 4 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/Source/kwsys/CMakeLists.txt b/Source/kwsys/CMakeLists.txt
index 124b8ac..a1eee0a 100644
--- a/Source/kwsys/CMakeLists.txt
+++ b/Source/kwsys/CMakeLists.txt
@@ -569,8 +569,10 @@ IF(KWSYS_USE_SystemTools)
     "Checking whether CXX compiler has unsetenv" DIRECT)
   KWSYS_PLATFORM_CXX_TEST(KWSYS_CXX_HAS_ENVIRON_IN_STDLIB_H
     "Checking whether CXX compiler has environ in stdlib.h" DIRECT)
+  KWSYS_PLATFORM_CXX_TEST(KWSYS_CXX_HAS_UTIMENSAT
+    "Checking whether CXX compiler has utimensat" DIRECT)
   SET_SOURCE_FILES_PROPERTIES(SystemTools.cxx PROPERTIES
-    COMPILE_FLAGS "-DKWSYS_CXX_HAS_SETENV=${KWSYS_CXX_HAS_SETENV} -DKWSYS_CXX_HAS_UNSETENV=${KWSYS_CXX_HAS_UNSETENV} -DKWSYS_CXX_HAS_ENVIRON_IN_STDLIB_H=${KWSYS_CXX_HAS_ENVIRON_IN_STDLIB_H}")
+    COMPILE_FLAGS "-DKWSYS_CXX_HAS_SETENV=${KWSYS_CXX_HAS_SETENV} -DKWSYS_CXX_HAS_UNSETENV=${KWSYS_CXX_HAS_UNSETENV} -DKWSYS_CXX_HAS_ENVIRON_IN_STDLIB_H=${KWSYS_CXX_HAS_ENVIRON_IN_STDLIB_H} -DKWSYS_CXX_HAS_UTIMENSAT=${KWSYS_CXX_HAS_UTIMENSAT}")
 ENDIF()
 
 IF(KWSYS_USE_SystemInformation)
diff --git a/Source/kwsys/SystemTools.cxx b/Source/kwsys/SystemTools.cxx
index 22bf193..402ae7a 100644
--- a/Source/kwsys/SystemTools.cxx
+++ b/Source/kwsys/SystemTools.cxx
@@ -1133,6 +1133,13 @@ bool SystemTools::Touch(const char* filename, bool create)
     {
     return false;
     }
+#if KWSYS_CXX_HAS_UTIMENSAT
+  struct timespec times[2] = {{0,UTIME_OMIT},{0,UTIME_NOW}};
+  if(utimensat(AT_FDCWD, filename, times, 0) < 0)
+    {
+    return false;
+    }
+#else
   struct utimbuf buf;
   buf.actime = fromStat.st_atime;
   buf.modtime = static_cast<time_t>(SystemTools::GetTime());
@@ -1140,6 +1147,7 @@ bool SystemTools::Touch(const char* filename, bool create)
     {
     return false;
     }
+#endif
   return true;
 }
 
diff --git a/Source/kwsys/kwsysPlatformTestsCXX.cxx b/Source/kwsys/kwsysPlatformTestsCXX.cxx
index 48976c4..ce4f00a 100644
--- a/Source/kwsys/kwsysPlatformTestsCXX.cxx
+++ b/Source/kwsys/kwsysPlatformTestsCXX.cxx
@@ -494,6 +494,16 @@ int main()
 }
 #endif
 
+#ifdef TEST_KWSYS_CXX_HAS_UTIMENSAT
+#include <fcntl.h>
+#include <sys/stat.h>
+int main()
+{
+  struct timespec times[2] = {{0,UTIME_OMIT},{0,UTIME_NOW}};
+  return utimensat(AT_FDCWD, "/example", times, AT_SYMLINK_NOFOLLOW);
+}
+#endif
+
 #ifdef TEST_KWSYS_CXX_TYPE_INFO
 /* Collect fundamental type information and save it to a CMake script.  */
 
diff --git a/bootstrap b/bootstrap
index 5c2addb..7fc2348 100755
--- a/bootstrap
+++ b/bootstrap
@@ -1082,6 +1082,7 @@ KWSYS_STL_HAS_ALLOCATOR_OBJECTS=0
 KWSYS_CXX_HAS_SETENV=0
 KWSYS_CXX_HAS_UNSETENV=0
 KWSYS_CXX_HAS_ENVIRON_IN_STDLIB_H=0
+KWSYS_CXX_HAS_UTIMENSAT=0
 KWSYS_CXX_HAS_CSTDDEF=0
 KWSYS_CXX_HAS_NULL_TEMPLATE_ARGS=0
 KWSYS_CXX_HAS_MEMBER_TEMPLATES=0
-- 
1.7.10.4