Support/FileSystem: Implement bool equivalent(file_status A, file_status B);

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146364 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/FileSystem.h

@@ -39,6 +39,10 @@
 #include <stack>
 #include <string>
 
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+
 namespace llvm {
 namespace sys {
 namespace fs {
@@ -94,7 +98,20 @@ struct space_info {
 ///               a platform specific member to store the result.
 class file_status
 {
-  // implementation defined status field.
+  #if defined(LLVM_ON_UNIX)
+  dev_t st_dev;
+  ino_t st_ino;
+  #elif defined (LLVM_ON_WIN32)
+  uint32_t LastWriteTimeHigh;
+  uint32_t LastWriteTimeLow;
+  uint32_t VolumeSerialNumber;
+  uint32_t FileSizeHigh;
+  uint32_t FileSizeLow;
+  uint32_t FileIndexHigh;
+  uint32_t FileIndexLow;
+  #endif
+  friend bool equivalent(file_status A, file_status B);
+  friend error_code status(const Twine &path, file_status &result);
   file_type Type;
 public:
   explicit file_status(file_type v=file_type::status_error)
@@ -244,6 +261,8 @@ bool equivalent(file_status A, file_status B);
 
 /// @brief Do paths represent the same thing?
 ///
+/// assert(status_known(A) || status_known(B));
+///
 /// @param A Input path A.
 /// @param B Input path B.
 /// @param result Set to true if stat(A) and stat(B) have the same device and

lib/Support/Unix/PathV2.inc

@@ -273,28 +273,17 @@ error_code exists(const Twine &path, bool &result) {
   return success;
 }
 
+bool equivalent(file_status A, file_status B) {
+  assert(status_known(A) && status_known(B));
+  return A.st_dev == B.st_dev &&
+         A.st_ino == B.st_ino;
+}
+
 error_code equivalent(const Twine &A, const Twine &B, bool &result) {
-  // Get arguments.
-  SmallString<128> a_storage;
-  SmallString<128> b_storage;
-  StringRef a = A.toNullTerminatedStringRef(a_storage);
-  StringRef b = B.toNullTerminatedStringRef(b_storage);
-
-  struct stat stat_a, stat_b;
-  int error_b = ::stat(b.begin(), &stat_b);
-  int error_a = ::stat(a.begin(), &stat_a);
-
-  // If both are invalid, it's an error. If only one is, the result is false.
-  if (error_a != 0 || error_b != 0) {
-    if (error_a == error_b)
-      return error_code(errno, system_category());
-    result = false;
-  } else {
-    result =
-      stat_a.st_dev == stat_b.st_dev &&
-      stat_a.st_ino == stat_b.st_ino;
-  }
-
+  file_status fsA, fsB;
+  if (error_code ec = status(A, fsA)) return ec;
+  if (error_code ec = status(B, fsB)) return ec;
+  result = equivalent(fsA, fsB);
   return success;
 }
 
@@ -341,6 +330,9 @@ error_code status(const Twine &path, file_status &result) {
   else
     result = file_status(file_type::type_unknown);
 
+  result.st_dev = status.st_dev;
+  result.st_ino = status.st_ino;
+
   return success;
 }
 

lib/Support/Windows/PathV2.inc

@@ -350,66 +350,22 @@ error_code exists(const Twine &path, bool &result) {
   return success;
 }
 
+bool equivalent(file_status A, file_status B) {
+  assert(status_known(A) && status_known(B));
+  return A.FileIndexHigh      == B.FileIndexHigh &&
+         A.FileIndexLow       == B.FileIndexLow &&
+         A.FileSizeHigh       == B.FileSizeHigh &&
+         A.FileSizeLow        == B.FileSizeLow &&
+         A.LastWriteTimeHigh  == B.LastWriteTimeHigh &&
+         A.LastWriteTimeLow   == B.LastWriteTimeLow &&
+         A.VolumeSerialNumber == B.VolumeSerialNumber;
+}
+
 error_code equivalent(const Twine &A, const Twine &B, bool &result) {
-  // Get arguments.
-  SmallString<128> a_storage;
-  SmallString<128> b_storage;
-  StringRef a = A.toStringRef(a_storage);
-  StringRef b = B.toStringRef(b_storage);
-
-  // Convert to utf-16.
-  SmallVector<wchar_t, 128> wide_a;
-  SmallVector<wchar_t, 128> wide_b;
-  if (error_code ec = UTF8ToUTF16(a, wide_a)) return ec;
-  if (error_code ec = UTF8ToUTF16(b, wide_b)) return ec;
-
-  ScopedFileHandle HandleB(
-    ::CreateFileW(wide_b.begin(),
-                  0,
-                  FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
-                  0,
-                  OPEN_EXISTING,
-                  FILE_FLAG_BACKUP_SEMANTICS,
-                  0));
-
-  ScopedFileHandle HandleA(
-    ::CreateFileW(wide_a.begin(),
-                  0,
-                  FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
-                  0,
-                  OPEN_EXISTING,
-                  FILE_FLAG_BACKUP_SEMANTICS,
-                  0));
-
-  // If both handles are invalid, it's an error.
-  if (!HandleA && !HandleB)
-    return windows_error(::GetLastError());
-
-  // If only one is invalid, it's false.
-  if (!HandleA || !HandleB) {
-    result = false;
-    return success;
-  }
-
-  // Get file information.
-  BY_HANDLE_FILE_INFORMATION InfoA, InfoB;
-  if (!::GetFileInformationByHandle(HandleA, &InfoA))
-    return windows_error(::GetLastError());
-  if (!::GetFileInformationByHandle(HandleB, &InfoB))
-    return windows_error(::GetLastError());
-
-  // See if it's all the same.
-  result =
-    InfoA.dwVolumeSerialNumber           == InfoB.dwVolumeSerialNumber &&
-    InfoA.nFileIndexHigh                 == InfoB.nFileIndexHigh &&
-    InfoA.nFileIndexLow                  == InfoB.nFileIndexLow &&
-    InfoA.nFileSizeHigh                  == InfoB.nFileSizeHigh &&
-    InfoA.nFileSizeLow                   == InfoB.nFileSizeLow &&
-    InfoA.ftLastWriteTime.dwLowDateTime  ==
-      InfoB.ftLastWriteTime.dwLowDateTime &&
-    InfoA.ftLastWriteTime.dwHighDateTime ==
-      InfoB.ftLastWriteTime.dwHighDateTime;
-
+  file_status fsA, fsB;
+  if (error_code ec = status(A, fsA)) return ec;
+  if (error_code ec = status(B, fsB)) return ec;
+  result = equivalent(fsA, fsB);
   return success;
 }
 
@@ -467,8 +423,7 @@ error_code status(const Twine &path, file_status &result) {
     return success;
   }
 
-  if (error_code ec = UTF8ToUTF16(path8,
-                                  path_utf16))
+  if (error_code ec = UTF8ToUTF16(path8, path_utf16))
     return ec;
 
   DWORD attr = ::GetFileAttributesW(path_utf16.begin());
@@ -491,8 +446,29 @@ error_code status(const Twine &path, file_status &result) {
 
   if (attr & FILE_ATTRIBUTE_DIRECTORY)
     result = file_status(file_type::directory_file);
-  else
+  else {
     result = file_status(file_type::regular_file);
+    ScopedFileHandle h(
+      ::CreateFileW(path_utf16.begin(),
+                    0, // Attributes only.
+                    FILE_SHARE_DELETE | FILE_SHARE_READ | FILE_SHARE_WRITE,
+                    NULL,
+                    OPEN_EXISTING,
+                    FILE_FLAG_BACKUP_SEMANTICS,
+                    0));
+    if (!h)
+      goto handle_status_error;
+    BY_HANDLE_FILE_INFORMATION Info;
+    if (!::GetFileInformationByHandle(h, &Info))
+      goto handle_status_error;
+    result.FileIndexHigh      = Info.nFileIndexHigh;
+    result.FileIndexLow       = Info.nFileIndexLow;
+    result.FileSizeHigh       = Info.nFileSizeHigh;
+    result.FileSizeLow        = Info.nFileSizeLow;
+    result.LastWriteTimeHigh  = Info.ftLastWriteTime.dwHighDateTime;
+    result.LastWriteTimeLow   = Info.ftLastWriteTime.dwLowDateTime;
+    result.VolumeSerialNumber = Info.dwVolumeSerialNumber;
+  }
 
   return success;
 

unittests/Support/Path.cpp

@@ -183,6 +183,11 @@ TEST_F(FileSystemTest, TempFiles) {
   ASSERT_NO_ERROR(fs::unique_file("%%-%%-%%-%%.temp", FD2, TempPath2));
   ASSERT_NE(TempPath.str(), TempPath2.str());
 
+  fs::file_status A, B;
+  ASSERT_NO_ERROR(fs::status(Twine(TempPath), A));
+  ASSERT_NO_ERROR(fs::status(Twine(TempPath2), B));
+  EXPECT_FALSE(fs::equivalent(A, B));
+
   // Try to copy the first to the second.
   EXPECT_EQ(
     fs::copy_file(Twine(TempPath), Twine(TempPath2)), errc::file_exists);
@@ -204,6 +209,9 @@ TEST_F(FileSystemTest, TempFiles) {
   bool equal;
   ASSERT_NO_ERROR(fs::equivalent(Twine(TempPath), Twine(TempPath2), equal));
   EXPECT_TRUE(equal);
+  ASSERT_NO_ERROR(fs::status(Twine(TempPath), A));
+  ASSERT_NO_ERROR(fs::status(Twine(TempPath2), B));
+  EXPECT_TRUE(fs::equivalent(A, B));
 
   // Remove Temp1.
   ::close(FileDescriptor);