Add disk_space() to llvm::fs

[mehdi_amini]

Summary

Adapted from Boost::filesystem.

[• rafael]

Can you return an ErrorOr or Expected?

[mehdi_amini]

Use ErrorOr in the API

[• rafael]

LGTM with nits.

lib/Support/Unix/Path.inc

217

Put STATVFS_F_FRSIZE(Vfs) in a variable. It is used 3 times.

git-clang-format the patch.

lib/Support/Windows/Path.inc

155

Avail, Total, Free.

[aaron.ballman]

Is there a reason we need this API?

[mehdi_amini]

clang-format (note: git clang-format does not run on .inc, I had to trick it)

[mehdi_amini]

Add two notes in the doxygen for Aaron comment (TOUTOC and windows quotas).

[ruiu]

include/llvm/Support/FileSystem.h

653

"reports reports"

660

const Twine Path -> const Twine &Path?

[ruiu]

include/llvm/Support/FileSystem.h

653

Ignore this comment -- I misread it.

[mehdi_amini]

r265068 (and r265074 for the Twine reference)

include/llvm/Support/FileSystem.h

 /// @param path Input path.
 /// @param result Set to the type of file, or file_magic::unknown.
 /// @returns errc::success if result has been successfully set, otherwise a
 ///          platform-specific error_code.
 std::error_code identify_magic(const Twine &path, file_magic &result);
 
 std::error_code getUniqueID(const Twine Path, UniqueID &Result);
 
+/// @brief Get disk space usage information.
+///
+/// @param Path Input path.
+/// @param SpaceInfo Set to the capacity, free, and available space on the
+///        device \a Path is on.
+/// @results errc::success if result has been successfully set, otherwise a
+///          platform specific error_code.
+std::error_code disk_space(const Twine Path, space_info &SpaceInfo);
+
 /// This class represents a memory mapped file. It is based on
 /// boost::iostreams::mapped_file.
 class mapped_file_region {
   mapped_file_region() = delete;
   mapped_file_region(mapped_file_region&) = delete;
   mapped_file_region &operator =(mapped_file_region&) = delete;
 
 public:
   enum mapmode {
     readonly, ///< May only access map via const_data as read only.

lib/Support/Unix/Path.inc

 #undef ferror
 #undef feof
 
 // For GNU Hurd
 #if defined(__GNU__) && !defined(PATH_MAX)
 # define PATH_MAX 4096
 #endif
 
+#include <sys/types.h>
+#if !defined(__APPLE__) && !defined(__OpenBSD__) && !defined(__ANDROID__)
+#  include <sys/statvfs.h>
+#  define STATVFS statvfs
+#  define STATVFS_F_FRSIZE(vfs) vfs.f_frsize
+#else
+# ifdef __OpenBSD__
+#  include <sys/param.h>
+# elif defined(__ANDROID__)
+#  include <sys/vfs.h>
+# else
+#  include <sys/mount.h>
+# endif
+# define STATVFS statfs
+# define STATVFS_F_FRSIZE(vfs) static_cast<uint64_t>(vfs.f_bsize)
+#endif
+
+
 using namespace llvm;
 
 namespace llvm {
 namespace sys  {
 namespace fs {
 #if defined(__FreeBSD__) || defined (__NetBSD__) || defined(__Bitrig__) || \
     defined(__OpenBSD__) || defined(__minix) || defined(__FreeBSD_kernel__) || \
     defined(__linux__) || defined(__CYGWIN__) || defined(__DragonFly__)
TimeValue file_status::getLastModificationTime() const {
   Ret.fromEpochTime(fs_st_mtime);
   return Ret;
 }
 
 UniqueID file_status::getUniqueID() const {
   return UniqueID(fs_st_dev, fs_st_ino);
 }
 
+std::error_code disk_space(const Twine Path, space_info &SpaceInfo) {
+  struct STATVFS Vfs;
+  if(::STATVFS(Path.str().c_str(), &Vfs))
+    return std::error_code(errno, std::generic_category());
+  SpaceInfo.capacity =
+      static_cast<uint64_t>(Vfs.f_blocks)* STATVFS_F_FRSIZE(Vfs);
+  SpaceInfo.free = static_cast<uint64_t>(Vfs.f_bfree)* STATVFS_F_FRSIZE(Vfs);
+  SpaceInfo.available =
+      static_cast<uint64_t>(Vfs.f_bavail)* STATVFS_F_FRSIZE(Vfs);
+  return std::error_code();
+}
+
 std::error_code current_path(SmallVectorImpl<char> &result) {
   result.clear();
 
   const char *pwd = ::getenv("PWD");
   llvm::sys::fs::file_status PWDStatus, DotStatus;
   if (pwd && llvm::sys::path::is_absolute(pwd) &&
       !llvm::sys::fs::status(pwd, PWDStatus) &&
       !llvm::sys::fs::status(".", DotStatus) &&

lib/Support/Windows/Path.inc

UniqueID file_status::getUniqueID() const {
   // The file is uniquely identified by the volume serial number along
   // with the 64-bit file identifier.
   uint64_t FileID = (static_cast<uint64_t>(FileIndexHigh) << 32ULL) |
                     static_cast<uint64_t>(FileIndexLow);
 
   return UniqueID(VolumeSerialNumber, FileID);
 }
 
+std::error_code disk_space(const Twine Path, space_info &SpaceInfo) {
+  PULARGE_INTEGER avail, total, free;
+  if (!::GetDiskFreeSpaceExW(Path.str().c_str(), &avail, &total, &free))
+      return mapWindowsError(::GetLastError());
+  SpaceInfo.capacity = (static_cast<uint64_t>(total.HighPart) << 32)
+    + total.LowPart;
+  SpaceInfo.free = (static_cast<uint64_t>(free.HighPart) << 32)
+    + free.LowPart;
+  SpaceInfo.available = (static_cast<uint64_t>(avail.HighPart) << 32)
+    + avail.LowPart;
+  return std::error_code();
+}
+
 TimeValue file_status::getLastAccessedTime() const {
   ULARGE_INTEGER UI;
   UI.LowPart = LastAccessedTimeLow;
   UI.HighPart = LastAccessedTimeHigh;
 
   TimeValue Ret;
   Ret.fromWin32Time(UI.QuadPart);
   return Ret;