eden: add helper for accessing stat fields as timespecs

Summary:
ported forward from D4209167, add a couple of helpers
to access these fields on mac and linux, centralizing/minimizing ifdefs.

Simplify some of the logic in FileChangeMonitor.

Reviewed By: chadaustin

Differential Revision: D13475717

fbshipit-source-id: d7b39999808bc41a6dc17a87189501cb34e68b30

eden/fs/config/FileChangeMonitor.cpp

@@ -15,22 +15,21 @@
 #ifdef EDEN_WIN
 #include "eden/win/fs/utils/Stub.h" // @manual
 #endif
+#include "eden/fs/utils/StatTimes.h"
+#include "eden/fs/utils/TimeUtil.h"
 
 namespace facebook {
 namespace eden {
 
 bool equalStats(const struct stat& stat1, const struct stat& stat2) noexcept {
-  return (
-      stat1.st_dev == stat2.st_dev && stat1.st_size == stat2.st_size &&
+  return stat1.st_dev == stat2.st_dev && stat1.st_size == stat2.st_size &&
       stat1.st_ino == stat2.st_ino && stat1.st_mode == stat2.st_mode &&
 #ifdef EDEN_WIN
-      stat1.st_ctime == stat2.st_ctime && stat1.st_mtime == stat2.st_mtime);
+      stat1.st_ctime == stat2.st_ctime && stat1.st_mtime == stat2.st_mtime
 #else
-      stat1.st_ctim.tv_sec == stat2.st_ctim.tv_sec &&
-      stat1.st_ctim.tv_nsec == stat2.st_ctim.tv_nsec &&
-      stat1.st_mtim.tv_sec == stat2.st_mtim.tv_sec &&
-      stat1.st_mtim.tv_nsec == stat2.st_mtim.tv_nsec);
+      stCtime(stat1) == stCtime(stat2) && stMtime(stat1) == stMtime(stat2)
 #endif
+      ;
 }
 AbsolutePath FileChangeMonitor::getFilePath() {
   return filePath_;

eden/fs/config/FileChangeMonitor.h

@@ -134,12 +134,8 @@ class FileChangeMonitor {
     // Set values for stat to force changedSinceUpdate() to return TRUE.
     // We use a novel setting to force change to be detected
     memset(&fileStat_, 0, sizeof(struct stat));
-#ifdef EDEN_WIN
     fileStat_.st_mtime = 1;
-#else
-    fileStat_.st_mtim.tv_sec = 1;
-    fileStat_.st_mtim.tv_nsec = 1;
-#endif
+
     statErrno_ = 0;
     openErrno_ = 0;
     // Set lastCheck in past so throttle does not apply.

eden/fs/fuse/Dispatcher.cpp

@@ -17,6 +17,7 @@
 
 #include "eden/fs/fuse/FileHandle.h"
 #include "eden/fs/fuse/RequestData.h"
+#include "eden/fs/utils/StatTimes.h"
 
 using namespace folly;
 using namespace std::chrono;
@@ -34,11 +35,11 @@ fuse_attr_out Dispatcher::Attr::asFuseAttr() const {
   result.attr.size = st.st_size;
   result.attr.blocks = st.st_blocks;
   result.attr.atime = st.st_atime;
-  result.attr.atimensec = st.st_atim.tv_nsec;
+  result.attr.atimensec = stAtime(st).tv_nsec;
   result.attr.mtime = st.st_mtime;
-  result.attr.mtimensec = st.st_mtim.tv_nsec;
+  result.attr.mtimensec = stMtime(st).tv_nsec;
   result.attr.ctime = st.st_ctime;
-  result.attr.ctimensec = st.st_ctim.tv_nsec;
+  result.attr.ctimensec = stCtime(st).tv_nsec;
   result.attr.mode = st.st_mode;
   result.attr.nlink = st.st_nlink;
   result.attr.uid = st.st_uid;

eden/fs/inodes/InodeTimestamps.cpp

@@ -149,7 +149,11 @@ void InodeTimestamps::setattrTimes(
 }
 
 void InodeTimestamps::applyToStat(struct stat& st) const {
-#if defined(_BSD_SOURCE) || defined(_SVID_SOURCE) || \
+#ifdef __APPLE__
+  st.st_atimespec = atime.toTimespec();
+  st.st_ctimespec = ctime.toTimespec();
+  st.st_mtimespec = mtime.toTimespec();
+#elif defined(_BSD_SOURCE) || defined(_SVID_SOURCE) || \
     _POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700
   st.st_atim = atime.toTimespec();
   st.st_ctim = ctime.toTimespec();

eden/fs/service/EdenServiceHandler.cpp

@@ -56,6 +56,7 @@
 #include "eden/fs/store/ObjectStore.h"
 #include "eden/fs/tracing/Tracing.h"
 #include "eden/fs/utils/ProcUtil.h"
+#include "eden/fs/utils/StatTimes.h"
 
 using folly::Future;
 using folly::makeFuture;
@@ -705,8 +706,9 @@ EdenServiceHandler::future_getFileInformation(
                    return inode->getattr().thenValue([](Dispatcher::Attr attr) {
                      FileInformation info;
                      info.size = attr.st.st_size;
-                     info.mtime.seconds = attr.st.st_mtim.tv_sec;
-                     info.mtime.nanoSeconds = attr.st.st_mtim.tv_nsec;
+                     auto& ts = stMtime(attr.st);
+                     info.mtime.seconds = ts.tv_sec;
+                     info.mtime.nanoSeconds = ts.tv_nsec;
                      info.mode = attr.st.st_mode;
 
                      FileInformationOrError result;

eden/fs/utils/StatTimes.h

@@ -0,0 +1,61 @@
+/*
+ *  Copyright (c) 2004-present, Facebook, Inc.
+ *  All rights reserved.
+ *
+ *  This source code is licensed under the BSD-style license found in the
+ *  LICENSE file in the root directory of this source tree. An additional grant
+ *  of patent rights can be found in the PATENTS file in the same directory.
+ *
+ */
+#pragma once
+#include <stdint.h>
+#include <time.h>
+
+namespace facebook {
+namespace eden {
+
+#ifndef _WIN32
+
+/** Helper for accessing the `atime` field of a `struct stat` as a timespec.
+ * Linux and macOS have different names for this field. */
+inline const struct timespec& stAtime(const struct stat& st) {
+#ifdef __APPLE__
+  return st.st_atimespec;
+#elif defined(_BSD_SOURCE) || defined(_SVID_SOURCE) || \
+    _POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700
+  return st.st_atim;
+#else
+#error teach this system how to get the stat change time as a timespec
+#endif
+}
+
+/** Helper for accessing the `mtime` field of a `struct stat` as a timespec.
+ * Linux and macOS have different names for this field. */
+inline const struct timespec& stMtime(const struct stat& st) {
+#ifdef __APPLE__
+  return st.st_mtimespec;
+#elif defined(_BSD_SOURCE) || defined(_SVID_SOURCE) || \
+    _POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700
+  return st.st_mtim;
+#else
+#error teach this system how to get the stat modify time as a timespec
+#endif
+}
+
+/** Helper for accessing the `ctime` field of a `struct stat` as a timespec.
+ * Linux and macOS have different names for this field. */
+inline const struct timespec& stCtime(const struct stat& st) {
+#ifdef __APPLE__
+  return st.st_ctimespec;
+#elif defined(_BSD_SOURCE) || defined(_SVID_SOURCE) || \
+    _POSIX_C_SOURCE >= 200809L || _XOPEN_SOURCE >= 700
+  return st.st_ctim;
+#else
+#error teach this system how to get the stat change time as a timespec
+#endif
+}
+
+#endif
+
+} // namespace eden
+} // namespace facebook