[llvm] r347530 - [Support/FileSystem] Add sub-second precision for atime/mtime of sys::fs::file_status on unix platforms
Argyrios Kyrtzidis via llvm-commits
llvm-commits at lists.llvm.org
Sun Nov 25 16:03:39 PST 2018
Author: akirtzidis
Date: Sun Nov 25 16:03:39 2018
New Revision: 347530
URL: http://llvm.org/viewvc/llvm-project?rev=347530&view=rev
Log:
[Support/FileSystem] Add sub-second precision for atime/mtime of sys::fs::file_status on unix platforms
Summary:
getLastAccessedTime() and getLastModificationTime() provided times in nanoseconds but with only 1 second resolution, even when the underlying file system could provide more precise times than that.
These changes add sub-second precision for unix platforms that support improved precision.
Also add some comments to make sure people are aware that the resolution of times can vary across different file systems.
Reviewers: labath, zturner, aaron.ballman, kristina
Reviewed By: aaron.ballman, kristina
Subscribers: lebedev.ri, mgorny, kristina, llvm-commits
Differential Revision: https://reviews.llvm.org/D54826
Modified:
llvm/trunk/cmake/config-ix.cmake
llvm/trunk/include/llvm/Config/config.h.cmake
llvm/trunk/include/llvm/Support/Chrono.h
llvm/trunk/include/llvm/Support/FileSystem.h
llvm/trunk/lib/Support/Unix/Path.inc
Modified: llvm/trunk/cmake/config-ix.cmake
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/cmake/config-ix.cmake?rev=347530&r1=347529&r2=347530&view=diff
==============================================================================
--- llvm/trunk/cmake/config-ix.cmake (original)
+++ llvm/trunk/cmake/config-ix.cmake Sun Nov 25 16:03:39 2018
@@ -7,6 +7,7 @@ include(CheckIncludeFile)
include(CheckLibraryExists)
include(CheckSymbolExists)
include(CheckFunctionExists)
+include(CheckStructHasMember)
include(CheckCCompilerFlag)
include(CheckCompilerVersion)
@@ -248,6 +249,11 @@ if( HAVE_DLFCN_H )
endif()
endif()
+CHECK_STRUCT_HAS_MEMBER("struct stat" st_mtimespec.tv_nsec
+ "sys/types.h;sys/stat.h" HAVE_STRUCT_STAT_ST_MTIMESPEC_TV_NSEC)
+CHECK_STRUCT_HAS_MEMBER("struct stat" st_mtim.tv_nsec
+ "sys/types.h;sys/stat.h" HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC)
+
check_symbol_exists(__GLIBC__ stdio.h LLVM_USING_GLIBC)
if( LLVM_USING_GLIBC )
add_definitions( -D_GNU_SOURCE )
Modified: llvm/trunk/include/llvm/Config/config.h.cmake
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Config/config.h.cmake?rev=347530&r1=347529&r2=347530&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Config/config.h.cmake (original)
+++ llvm/trunk/include/llvm/Config/config.h.cmake Sun Nov 25 16:03:39 2018
@@ -208,6 +208,12 @@
/* Define to 1 if you have the <sys/time.h> header file. */
#cmakedefine HAVE_SYS_TIME_H ${HAVE_SYS_TIME_H}
+/* Define to 1 if stat struct has st_mtimespec member .*/
+#cmakedefine HAVE_STRUCT_STAT_ST_MTIMESPEC_TV_NSEC ${HAVE_STRUCT_STAT_ST_MTIMESPEC_TV_NSEC}
+
+/* Define to 1 if stat struct has st_mtim member. */
+#cmakedefine HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC ${HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC}
+
/* Define to 1 if you have the <sys/types.h> header file. */
#cmakedefine HAVE_SYS_TYPES_H ${HAVE_SYS_TYPES_H}
Modified: llvm/trunk/include/llvm/Support/Chrono.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/Chrono.h?rev=347530&r1=347529&r2=347530&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/Chrono.h (original)
+++ llvm/trunk/include/llvm/Support/Chrono.h Sun Nov 25 16:03:39 2018
@@ -47,6 +47,14 @@ toTimePoint(std::time_t T) {
return time_point_cast<seconds>(system_clock::from_time_t(T));
}
+/// Convert a std::time_t + nanoseconds to a TimePoint
+LLVM_ATTRIBUTE_ALWAYS_INLINE inline TimePoint<>
+toTimePoint(std::time_t T, uint32_t nsec) {
+ using namespace std::chrono;
+ return time_point_cast<nanoseconds>(system_clock::from_time_t(T))
+ + nanoseconds(nsec);
+}
+
} // namespace sys
raw_ostream &operator<<(raw_ostream &OS, sys::TimePoint<> TP);
Modified: llvm/trunk/include/llvm/Support/FileSystem.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/FileSystem.h?rev=347530&r1=347529&r2=347530&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/FileSystem.h (original)
+++ llvm/trunk/include/llvm/Support/FileSystem.h Sun Nov 25 16:03:39 2018
@@ -160,6 +160,8 @@ protected:
#if defined(LLVM_ON_UNIX)
time_t fs_st_atime = 0;
time_t fs_st_mtime = 0;
+ uint32_t fs_st_atime_nsec = 0;
+ uint32_t fs_st_mtime_nsec = 0;
uid_t fs_st_uid = 0;
gid_t fs_st_gid = 0;
off_t fs_st_size = 0;
@@ -180,9 +182,12 @@ public:
explicit basic_file_status(file_type Type) : Type(Type) {}
#if defined(LLVM_ON_UNIX)
- basic_file_status(file_type Type, perms Perms, time_t ATime, time_t MTime,
+ basic_file_status(file_type Type, perms Perms, time_t ATime,
+ uint32_t ATimeNSec, time_t MTime, uint32_t MTimeNSec,
uid_t UID, gid_t GID, off_t Size)
- : fs_st_atime(ATime), fs_st_mtime(MTime), fs_st_uid(UID), fs_st_gid(GID),
+ : fs_st_atime(ATime), fs_st_mtime(MTime),
+ fs_st_atime_nsec(ATimeNSec), fs_st_mtime_nsec(MTimeNSec),
+ fs_st_uid(UID), fs_st_gid(GID),
fs_st_size(Size), Type(Type), Perms(Perms) {}
#elif defined(_WIN32)
basic_file_status(file_type Type, perms Perms, uint32_t LastAccessTimeHigh,
@@ -199,7 +204,20 @@ public:
// getters
file_type type() const { return Type; }
perms permissions() const { return Perms; }
+
+ /// The file access time as reported from the underlying file system.
+ ///
+ /// Also see comments on \c getLastModificationTime() related to the precision
+ /// of the returned value.
TimePoint<> getLastAccessedTime() const;
+
+ /// The file modification time as reported from the underlying file system.
+ ///
+ /// The returned value allows for nanosecond precision but the actual
+ /// resolution is an implementation detail of the underlying file system.
+ /// There is no guarantee for what kind of resolution you can expect, the
+ /// resolution can differ across platforms and even across mountpoints on the
+ /// same machine.
TimePoint<> getLastModificationTime() const;
#if defined(LLVM_ON_UNIX)
@@ -247,8 +265,11 @@ public:
#if defined(LLVM_ON_UNIX)
file_status(file_type Type, perms Perms, dev_t Dev, nlink_t Links, ino_t Ino,
- time_t ATime, time_t MTime, uid_t UID, gid_t GID, off_t Size)
- : basic_file_status(Type, Perms, ATime, MTime, UID, GID, Size),
+ time_t ATime, uint32_t ATimeNSec,
+ time_t MTime, uint32_t MTimeNSec,
+ uid_t UID, gid_t GID, off_t Size)
+ : basic_file_status(Type, Perms, ATime, ATimeNSec, MTime, MTimeNSec,
+ UID, GID, Size),
fs_st_dev(Dev), fs_st_nlinks(Links), fs_st_ino(Ino) {}
#elif defined(_WIN32)
file_status(file_type Type, perms Perms, uint32_t LinkCount,
Modified: llvm/trunk/lib/Support/Unix/Path.inc
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Unix/Path.inc?rev=347530&r1=347529&r2=347530&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Unix/Path.inc (original)
+++ llvm/trunk/lib/Support/Unix/Path.inc Sun Nov 25 16:03:39 2018
@@ -229,11 +229,11 @@ std::string getMainExecutable(const char
}
TimePoint<> basic_file_status::getLastAccessedTime() const {
- return toTimePoint(fs_st_atime);
+ return toTimePoint(fs_st_atime, fs_st_atime_nsec);
}
TimePoint<> basic_file_status::getLastModificationTime() const {
- return toTimePoint(fs_st_mtime);
+ return toTimePoint(fs_st_mtime, fs_st_mtime_nsec);
}
UniqueID file_status::getUniqueID() const {
@@ -591,11 +591,22 @@ static std::error_code fillStatus(int St
return EC;
}
+ uint32_t atime_nsec, mtime_nsec;
+#if defined(HAVE_STRUCT_STAT_ST_MTIMESPEC_TV_NSEC)
+ atime_nsec = Status.st_atimespec.tv_nsec;
+ mtime_nsec = Status.st_mtimespec.tv_nsec;
+#elif defined(HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC)
+ atime_nsec = Status.st_atim.tv_nsec;
+ mtime_nsec = Status.st_mtim.tv_nsec;
+#else
+ atime_nsec = mtime_nsec = 0;
+#endif
+
perms Perms = static_cast<perms>(Status.st_mode) & all_perms;
Result = file_status(typeForMode(Status.st_mode), Perms, Status.st_dev,
- Status.st_nlink, Status.st_ino, Status.st_atime,
- Status.st_mtime, Status.st_uid, Status.st_gid,
- Status.st_size);
+ Status.st_nlink, Status.st_ino,
+ Status.st_atime, atime_nsec, Status.st_mtime, mtime_nsec,
+ Status.st_uid, Status.st_gid, Status.st_size);
return std::error_code();
}
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