From e1136e38a7c5cf84ab16e4f0d50c6a8f4bde0ff4 Mon Sep 17 00:00:00 2001
From: Rafael Espindola <rafael.espindola@gmail.com>
Date: Fri, 12 Dec 2014 17:55:12 +0000
Subject: [PATCH] Pass a FD to resise_file and add a testcase.

I will add a real use in another commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224136 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Support/FileSystem.h |  4 ++--
 lib/Support/Unix/Path.inc         |  7 ++-----
 lib/Support/Windows/Path.inc      | 16 ++++------------
 unittests/Support/Path.cpp        | 10 ++++++++++
 4 files changed, 18 insertions(+), 19 deletions(-)

diff --git a/include/llvm/Support/FileSystem.h b/include/llvm/Support/FileSystem.h
index 09561fcb0f2..2bd36c042d4 100644
--- a/include/llvm/Support/FileSystem.h
+++ b/include/llvm/Support/FileSystem.h
@@ -336,11 +336,11 @@ std::error_code copy_file(const Twine &From, const Twine &To);
 
 /// @brief Resize path to size. File is resized as if by POSIX truncate().
 ///
-/// @param path Input path.
+/// @param path Input file descriptor.
 /// @param size Size to resize to.
 /// @returns errc::success if \a path has been resized to \a size, otherwise a
 ///          platform-specific error_code.
-std::error_code resize_file(const Twine &path, uint64_t size);
+std::error_code resize_file(int FD, uint64_t Size);
 
 /// @}
 /// @name Physical Observers
diff --git a/lib/Support/Unix/Path.inc b/lib/Support/Unix/Path.inc
index 1e1b911b78b..75bcc03bbd3 100644
--- a/lib/Support/Unix/Path.inc
+++ b/lib/Support/Unix/Path.inc
@@ -286,11 +286,8 @@ std::error_code rename(const Twine &from, const Twine &to) {
   return std::error_code();
 }
 
-std::error_code resize_file(const Twine &path, uint64_t size) {
-  SmallString<128> path_storage;
-  StringRef p = path.toNullTerminatedStringRef(path_storage);
-
-  if (::truncate(p.begin(), size) == -1)
+std::error_code resize_file(int FD, uint64_t Size) {
+  if (::ftruncate(FD, Size) == -1)
     return std::error_code(errno, std::generic_category());
 
   return std::error_code();
diff --git a/lib/Support/Windows/Path.inc b/lib/Support/Windows/Path.inc
index 20eae54b181..05c0986d049 100644
--- a/lib/Support/Windows/Path.inc
+++ b/lib/Support/Windows/Path.inc
@@ -272,21 +272,13 @@ std::error_code rename(const Twine &from, const Twine &to) {
   return ec;
 }
 
-std::error_code resize_file(const Twine &path, uint64_t size) {
-  SmallVector<wchar_t, 128> path_utf16;
-
-  if (std::error_code ec = widenPath(path, path_utf16))
-    return ec;
-
-  int fd = ::_wopen(path_utf16.begin(), O_BINARY | _O_RDWR, S_IWRITE);
-  if (fd == -1)
-    return std::error_code(errno, std::generic_category());
+std::error_code resize_file(int FD, uint64_t Size) {
 #ifdef HAVE__CHSIZE_S
-  errno_t error = ::_chsize_s(fd, size);
+  errno_t error = ::_chsize_s(FD, Size);
 #else
-  errno_t error = ::_chsize(fd, size);
+  errno_t error = ::_chsize(FD, Size);
 #endif
-  ::close(fd);
+  ::close(FD);
   return std::error_code(error, std::generic_category());
 }
 
diff --git a/unittests/Support/Path.cpp b/unittests/Support/Path.cpp
index 81d92342764..88baadeca02 100644
--- a/unittests/Support/Path.cpp
+++ b/unittests/Support/Path.cpp
@@ -638,6 +638,16 @@ TEST_F(FileSystemTest, CarriageReturn) {
 }
 #endif
 
+TEST_F(FileSystemTest, Resize) {
+  int FD;
+  SmallString<64> TempPath;
+  ASSERT_NO_ERROR(fs::createTemporaryFile("prefix", "temp", FD, TempPath));
+  ASSERT_NO_ERROR(fs::resize_file(FD, 123));
+  fs::file_status Status;
+  ASSERT_NO_ERROR(fs::status(FD, Status));
+  ASSERT_EQ(Status.getSize(), 123U);
+}
+
 TEST_F(FileSystemTest, FileMapping) {
   // Create a temp file.
   int FileDescriptor;
-- 
2.34.1