Implement get_magic with generic tools and inline it.

llvm-svn: 210716

diff --git a/llvm/include/llvm/Support/FileSystem.h b/llvm/include/llvm/Support/FileSystem.h
index dbf8f99..b5dcc66 100644 (file)
--- a/llvm/include/llvm/Support/FileSystem.h
+++ b/llvm/include/llvm/Support/FileSystem.h
@@ -603,19 +603,6 @@ error_code openFileForWrite(const Twine &Name, int &ResultFD, OpenFlags Flags,
 
 error_code openFileForRead(const Twine &Name, int &ResultFD);
 
-/// @brief Get \a path's first \a len bytes.
-///
-/// @param path Input path.
-/// @param len Number of magic bytes to get.
-/// @param result Set to the first \a len bytes in the file pointed to by
-///               \a path. Or the entire file if file_size(path) < len, in which
-///               case result.size() returns the size of the file.
-/// @returns errc::success if result has been successfully set,
-///          errc::value_too_large if len is larger then the file pointed to by
-///          \a path, otherwise a platform specific error_code.
-error_code get_magic(const Twine &path, uint32_t len,
-                     SmallVectorImpl<char> &result);
-
 /// @brief Identify the type of a binary file based on how magical it is.
 file_magic identify_magic(StringRef magic);
 

diff --git a/llvm/lib/Support/Path.cpp b/llvm/lib/Support/Path.cpp
index c063bed..9d98503 100644 (file)
--- a/llvm/lib/Support/Path.cpp
+++ b/llvm/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/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index ef291db..7ebf1b4 100644 (file)
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/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/llvm/lib/Support/Windows/Path.inc b/llvm/lib/Support/Windows/Path.inc
index fb48477..6a5792e 100644 (file)
--- a/llvm/lib/Support/Windows/Path.inc
+++ b/llvm/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.