[FileSystem] Make file_status store link count and add a file_status::getLinkCount() method.

[sas]

llvm/include/llvm/Support/FileSystem.h

167

It seems like system types are used here when LLVM_ON_UNIX is defined, so you should probably define LinkCount as nlink_t fs_st_nlink; for POSIX and uint32_t LinkCount; only for the Windows case (which means you'll also have to have two separate getters down below).

I'll let someone more knowledgeable with this code confirm what the right thing to do is.

[labath]

llvm/include/llvm/Support/FileSystem.h

167

That certainly seems to be the pattern, although I am not really sure why. I am personally fine with having a single field if it is big enough to hold the value in all circumstances -- which means the type should be 64-bit as that's the type of nlink_t on 64-bit (linux) systems.

llvm/include/llvm/Support/FileSystem.h

class file_status
   uint32_t LastWriteTimeHigh = 0;
   uint32_t LastWriteTimeLow = 0;
   uint32_t VolumeSerialNumber = 0;
   uint32_t FileSizeHigh = 0;
   uint32_t FileSizeLow = 0;
   uint32_t FileIndexHigh = 0;
   uint32_t FileIndexLow = 0;
   #endif
+  uint32_t LinkCount = 0;
   file_type Type = file_type::status_error;
   perms Perms = perms_not_known;
 
 public:
   #if defined(LLVM_ON_UNIX)
   file_status() = default;
 
   file_status(file_type Type) : Type(Type) {}
 
-  file_status(file_type Type, perms Perms, dev_t Dev, ino_t Ino, time_t ATime,
-              time_t MTime, uid_t UID, gid_t GID, off_t Size)
-      : fs_st_dev(Dev), fs_st_ino(Ino), fs_st_atime(ATime), fs_st_mtime(MTime),
-        fs_st_uid(UID), fs_st_gid(GID), fs_st_size(Size), Type(Type),
-        Perms(Perms) {}
+  file_status(file_type Type, perms Perms, dev_t Dev, uint32_t Links, ino_t Ino,
+              time_t ATime, time_t MTime, uid_t UID, gid_t GID, off_t Size)
+      : fs_st_dev(Dev), LinkCount(Links), fs_st_ino(Ino), fs_st_atime(ATime),
+        fs_st_mtime(MTime), fs_st_uid(UID), fs_st_gid(GID), fs_st_size(Size),
+        Type(Type), Perms(Perms) {}
   #elif defined(LLVM_ON_WIN32)
   file_status() = default;
 
   file_status(file_type Type) : Type(Type) {}
 
-  file_status(file_type Type, perms Perms, uint32_t LastAccessTimeHigh,
-              uint32_t LastAccessTimeLow, uint32_t LastWriteTimeHigh,
-              uint32_t LastWriteTimeLow, uint32_t VolumeSerialNumber,
-              uint32_t FileSizeHigh, uint32_t FileSizeLow,
-              uint32_t FileIndexHigh, uint32_t FileIndexLow)
-      : LastAccessedTimeHigh(LastAccessTimeHigh), LastAccessedTimeLow(LastAccessTimeLow),
+  file_status(file_type Type, perms Perms, uint32_t LinkCount,
+              uint32_t LastAccessTimeHigh, uint32_t LastAccessTimeLow,
+              uint32_t LastWriteTimeHigh, uint32_t LastWriteTimeLow,
+              uint32_t VolumeSerialNumber, uint32_t FileSizeHigh,
+              uint32_t FileSizeLow, uint32_t FileIndexHigh,
+              uint32_t FileIndexLow)
+      : LinkCount(LinkCount), LastAccessedTimeHigh(LastAccessTimeHigh),
+        LastAccessedTimeLow(LastAccessTimeLow),
         LastWriteTimeHigh(LastWriteTimeHigh),
         LastWriteTimeLow(LastWriteTimeLow),
         VolumeSerialNumber(VolumeSerialNumber), FileSizeHigh(FileSizeHigh),
         FileSizeLow(FileSizeLow), FileIndexHigh(FileIndexHigh),
         FileIndexLow(FileIndexLow), Type(Type), Perms(Perms) {}
   #endif
 
   // getters
   file_type type() const { return Type; }
   perms permissions() const { return Perms; }
   TimePoint<> getLastAccessedTime() const;
   TimePoint<> getLastModificationTime() const;
   UniqueID getUniqueID() const;
+  uint32_t getLinkCount() const { return LinkCount; }
 
   #if defined(LLVM_ON_UNIX)
   uint32_t getUser() const { return fs_st_uid; }
   uint32_t getGroup() const { return fs_st_gid; }
   uint64_t getSize() const { return fs_st_size; }
   #elif defined (LLVM_ON_WIN32)
   uint32_t getUser() const {
     return 9999; // Not applicable to Windows, so...

llvm/lib/Support/Unix/Path.inc

static std::error_code fillStatus(int StatRet, const struct stat &Status,
   else if (S_ISFIFO(Status.st_mode))
     Type = file_type::fifo_file;
   else if (S_ISSOCK(Status.st_mode))
     Type = file_type::socket_file;
   else if (S_ISLNK(Status.st_mode))
     Type = file_type::symlink_file;
 
   perms Perms = static_cast<perms>(Status.st_mode) & all_perms;
-  Result =
-      file_status(Type, Perms, Status.st_dev, Status.st_ino, Status.st_atime,
-                  Status.st_mtime, Status.st_uid, Status.st_gid,
-                  Status.st_size);
+  Result = file_status(Type, 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);
 
   return std::error_code();
 }
 
 std::error_code status(const Twine &Path, file_status &Result, bool Follow) {
   SmallString<128> PathStorage;
   StringRef P = Path.toNullTerminatedStringRef(PathStorage);
 

llvm/lib/Support/Windows/Path.inc

static std::error_code getStatus(HANDLE FileHandle, file_status &Result) {
   {
     file_type Type = (Info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
                          ? file_type::directory_file
                          : file_type::regular_file;
     perms Permissions = (Info.dwFileAttributes & FILE_ATTRIBUTE_READONLY)
                             ? (all_read | all_exe)
                             : all_all;
     Result = file_status(
-        Type, Permissions, Info.ftLastAccessTime.dwHighDateTime,
+        Type, Permissions, Info.nNumberOfLinks,
+        Info.ftLastAccessTime.dwHighDateTime,
         Info.ftLastAccessTime.dwLowDateTime,
         Info.ftLastWriteTime.dwHighDateTime, Info.ftLastWriteTime.dwLowDateTime,
         Info.dwVolumeSerialNumber, Info.nFileSizeHigh, Info.nFileSizeLow,
         Info.nFileIndexHigh, Info.nFileIndexLow);
     return std::error_code();
   }
 
 handle_status_error: