Implement get_magic with generic tools and inline it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210716 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 10 insertions, 79 deletions

diff --git a/lib/Support/Path.cpp b/lib/Support/Path.cpp
index c063bed2b5..9d98503e02 100644
--- a/lib/Support/Path.cpp
+++ b/lib/Support/Path.cpp
@@ -1022,13 +1022,17 @@ void directory_entry::replace_filename(const Twine &filename, file_status st) {
   return file_magic::unknown;
 }
 
-error_code identify_magic(const Twine &path, file_magic &result) {
-  SmallString<32> Magic;
-  error_code ec = get_magic(path, Magic.capacity(), Magic);
-  if (ec && ec != std::errc::value_too_large)
-    return ec;
+error_code identify_magic(const Twine &Path, file_magic &Result) {
+  int FD;
+  if (error_code EC = openFileForRead(Path, FD))
+    return EC;
+
+  char Buffer[32];
+  int Length = read(FD, Buffer, sizeof(Buffer));
+  if (Length < 0)
+    return error_code(errno, generic_category());
 
-  result = identify_magic(Magic);
+  Result = identify_magic(StringRef(Buffer, Length));
   return error_code();
 }
 
diff --git a/lib/Support/Unix/Path.inc b/lib/Support/Unix/Path.inc
index ef291db52d..7ebf1b4962 100644
--- a/lib/Support/Unix/Path.inc
+++ b/lib/Support/Unix/Path.inc
@@ -622,37 +622,6 @@ error_code detail::directory_iterator_increment(detail::DirIterState &it) {
   return error_code();
 }
 
-error_code get_magic(const Twine &path, uint32_t len,
-                     SmallVectorImpl<char> &result) {
-  SmallString<128> PathStorage;
-  StringRef Path = path.toNullTerminatedStringRef(PathStorage);
-  result.set_size(0);
-
-  // Open path.
-  std::FILE *file = std::fopen(Path.data(), "rb");
-  if (!file)
-    return error_code(errno, generic_category());
-
-  // Reserve storage.
-  result.reserve(len);
-
-  // Read magic!
-  size_t size = std::fread(result.data(), 1, len, file);
-  if (std::ferror(file) != 0) {
-    std::fclose(file);
-    return error_code(errno, generic_category());
-  } else if (size != len) {
-    if (std::feof(file) != 0) {
-      std::fclose(file);
-      result.set_size(size);
-      return make_error_code(std::errc::value_too_large);
-    }
-  }
-  std::fclose(file);
-  result.set_size(size);
-  return error_code();
-}
-
 error_code openFileForRead(const Twine &Name, int &ResultFD) {
   SmallString<128> Storage;
   StringRef P = Name.toNullTerminatedStringRef(Storage);
diff --git a/lib/Support/Windows/Path.inc b/lib/Support/Windows/Path.inc
index fb484778e6..6a5792e70c 100644
--- a/lib/Support/Windows/Path.inc
+++ b/lib/Support/Windows/Path.inc
@@ -466,48 +466,6 @@ error_code setLastModificationAndAccessTime(int FD, TimeValue Time) {
   return error_code();
 }
 
-error_code get_magic(const Twine &path, uint32_t len,
-                     SmallVectorImpl<char> &result) {
-  SmallString<128> path_storage;
-  SmallVector<wchar_t, 128> path_utf16;
-  result.set_size(0);
-
-  // Convert path to UTF-16.
-  if (error_code ec = UTF8ToUTF16(path.toStringRef(path_storage),
-                                  path_utf16))
-    return ec;
-
-  // Open file.
-  HANDLE file = ::CreateFileW(c_str(path_utf16),
-                              GENERIC_READ,
-                              FILE_SHARE_READ,
-                              NULL,
-                              OPEN_EXISTING,
-                              FILE_ATTRIBUTE_READONLY,
-                              NULL);
-  if (file == INVALID_HANDLE_VALUE)
-    return windows_error(::GetLastError());
-
-  // Allocate buffer.
-  result.reserve(len);
-
-  // Get magic!
-  DWORD bytes_read = 0;
-  BOOL read_success = ::ReadFile(file, result.data(), len, &bytes_read, NULL);
-  error_code ec = windows_error(::GetLastError());
-  ::CloseHandle(file);
-  if (!read_success || (bytes_read != len)) {
-    // Set result size to the number of bytes read if it's valid.
-    if (bytes_read <= len)
-      result.set_size(bytes_read);
-    // ERROR_HANDLE_EOF is mapped to errc::value_too_large.
-    return ec;
-  }
-
-  result.set_size(len);
-  return error_code();
-}
-
 error_code mapped_file_region::init(int FD, bool CloseFD, uint64_t Offset) {
   FileDescriptor = FD;
   // Make sure that the requested size fits within SIZE_T.