file_util.cc

// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/file_util.h"

#include <stdio.h>

#include <fstream>

#include "base/file_path.h"
#include "base/logging.h"
#include "base/string_util.h"
#include "unicode/uniset.h"

#include "base/string_piece.h"
#include "base/sys_string_conversions.h"

namespace {

const FilePath::CharType kExtensionSeparator = FILE_PATH_LITERAL('.');

}

namespace file_util {

void PathComponents(const FilePath& path,
                    std::vector<FilePath::StringType>* components) {
  DCHECK(components);
  if (!components)
    return;

  FilePath::StringType path_str = path.value();
  FilePath::StringType::size_type start = 0;
  FilePath::StringType::size_type end =
      path_str.find_first_of(FilePath::kSeparators);

  // If the path starts with a separator, add it to components.
  if (end == start) {
    components->push_back(FilePath::StringType(path_str, 0, 1));
    start = end + 1;
    end = path_str.find_first_of(FilePath::kSeparators, start);
  }
  while (end != FilePath::StringType::npos) {
    FilePath::StringType component =
        FilePath::StringType(path_str, start, end - start);
    components->push_back(component);
    start = end + 1;
    end = path_str.find_first_of(FilePath::kSeparators, start);
  }

  components->push_back(FilePath::StringType(path_str, start));
}

bool EndsWithSeparator(const FilePath& path) {
  FilePath::StringType value = path.value();
  if (value.empty())
    return false;

  return FilePath::IsSeparator(value[value.size() - 1]);
}

bool EnsureEndsWithSeparator(FilePath* path) {
  if (!DirectoryExists(*path))
    return false;

  if (EndsWithSeparator(*path))
    return true;

  FilePath::StringType& path_str =
      const_cast<FilePath::StringType&>(path->value());
  path_str.append(&FilePath::kSeparators[0], 1);

  return true;
}

void TrimTrailingSeparator(std::wstring* dir) {
  while (dir->length() > 1 && EndsWithSeparator(dir))
    dir->resize(dir->length() - 1);
}

std::wstring GetFileExtensionFromPath(const std::wstring& path) {
  std::wstring file_name = GetFilenameFromPath(path);
  std::wstring::size_type last_dot = file_name.rfind(L'.');
  return std::wstring(last_dot == std::wstring::npos ? 
      L"" : 
      file_name, last_dot+1);
}

std::wstring GetFilenameWithoutExtensionFromPath(const std::wstring& path) {
  std::wstring file_name = GetFilenameFromPath(path);
  std::wstring::size_type last_dot = file_name.rfind(L'.');
  return file_name.substr(0, last_dot);
}

void InsertBeforeExtension(FilePath* path, const FilePath::StringType& suffix) {
  FilePath::StringType& value =
      const_cast<FilePath::StringType&>(path->value());

  const FilePath::StringType::size_type last_dot =
      value.rfind(kExtensionSeparator);
  const FilePath::StringType::size_type last_separator =
      value.find_last_of(FilePath::StringType(FilePath::kSeparators));

  if (last_dot == FilePath::StringType::npos ||
      (last_separator != std::wstring::npos && last_dot < last_separator)) {
    // The path looks something like "C:\pics.old\jojo" or "C:\pics\jojo".
    // We should just append the suffix to the entire path.
    value.append(suffix);
    return;
  }

  value.insert(last_dot, suffix);
}

void ReplaceExtension(FilePath* path, const FilePath::StringType& extension) {
  FilePath::StringType clean_extension;
  // If the new extension is "" or ".", then we will just remove the current
  // extension.
  if (!extension.empty() &&
      extension != FilePath::StringType(&kExtensionSeparator, 1)) {
    if (extension[0] != kExtensionSeparator)
      clean_extension.append(&kExtensionSeparator, 1);
    clean_extension.append(extension);
  }

  FilePath::StringType& value =
      const_cast<FilePath::StringType&>(path->value());
  const FilePath::StringType::size_type last_dot =
      value.rfind(kExtensionSeparator);
  const FilePath::StringType::size_type last_separator =
      value.find_last_of(FilePath::StringType(FilePath::kSeparators));

  // Erase the current extension, if any.
  if ((last_dot > last_separator ||
      last_separator == FilePath::StringType::npos) &&
      last_dot != FilePath::StringType::npos)
    value.erase(last_dot);

  value.append(clean_extension);
}

void ReplaceIllegalCharacters(std::wstring* file_name, int replace_char) {
  DCHECK(file_name);

  // Control characters, formatting characters, non-characters, and
  // some printable ASCII characters regarded as dangerous ('"*/:<>?\\').
  // See  http://blogs.msdn.com/michkap/archive/2006/11/03/941420.aspx
  // and http://msdn2.microsoft.com/en-us/library/Aa365247.aspx
  // TODO(jungshik): Revisit the set. ZWJ and ZWNJ are excluded because they
  // are legitimate in Arabic and some S/SE Asian scripts. However, when used
  // elsewhere, they can be confusing/problematic.
  // Also, consider wrapping the set with our Singleton class to create and
  // freeze it only once. Note that there's a trade-off between memory and
  // speed.

  UErrorCode status = U_ZERO_ERROR;
#if defined(WCHAR_T_IS_UTF16)
  UnicodeSet illegal_characters(UnicodeString(
      L"[[\"*/:<>?\\\\|][:Cc:][:Cf:] - [\u200c\u200d]]"), status);
#else
  UnicodeSet illegal_characters(UNICODE_STRING_SIMPLE(
      "[[\"*/:<>?\\\\|][:Cc:][:Cf:] - [\\u200c\\u200d]]").unescape(), status);
#endif
  DCHECK(U_SUCCESS(status));
  // Add non-characters. If this becomes a performance bottleneck by
  // any chance, check |ucs4 & 0xFFFEu == 0xFFFEu|, instead.
  illegal_characters.add(0xFDD0, 0xFDEF);
  for (int i = 0; i <= 0x10; ++i) {
    int plane_base = 0x10000 * i;
    illegal_characters.add(plane_base + 0xFFFE, plane_base + 0xFFFF);
  }
  illegal_characters.freeze();
  DCHECK(!illegal_characters.contains(replace_char) && replace_char < 0x10000);

  // Remove leading and trailing whitespace.
  TrimWhitespace(*file_name, TRIM_ALL, file_name);

  std::wstring::size_type i = 0;
  std::wstring::size_type length = file_name->size();
  const wchar_t* wstr = file_name->data();
#if defined(WCHAR_T_IS_UTF16)
  // Using |span| method of UnicodeSet might speed things up a bit, but
  // it's not likely to matter here.
  std::wstring temp;
  temp.reserve(length);
  while (i < length) {
    UChar32 ucs4;
    std::wstring::size_type prev = i;
    U16_NEXT(wstr, i, length, ucs4);
    if (illegal_characters.contains(ucs4)) {
      temp.push_back(replace_char);
    } else if (ucs4 < 0x10000) {
      temp.push_back(ucs4);
    } else {
      temp.push_back(wstr[prev]);
      temp.push_back(wstr[prev + 1]);
    }
  }
  file_name->swap(temp);
#elif defined(WCHAR_T_IS_UTF32)
  while (i < length) {
    if (illegal_characters.contains(wstr[i])) {
      (*file_name)[i] = replace_char;
    }
    ++i;
  }
#else
#error wchar_t* should be either UTF-16 or UTF-32
#endif
}

bool ContentsEqual(const FilePath& filename1, const FilePath& filename2) {
  // We open the file in binary format even if they are text files because
  // we are just comparing that bytes are exactly same in both files and not
  // doing anything smart with text formatting.
  std::ifstream file1(filename1.value().c_str(),
                      std::ios::in | std::ios::binary);
  std::ifstream file2(filename2.value().c_str(),
                      std::ios::in | std::ios::binary);

  // Even if both files aren't openable (and thus, in some sense, "equal"),
  // any unusable file yields a result of "false".
  if (!file1.is_open() || !file2.is_open())
    return false;

  const int BUFFER_SIZE = 2056;
  char buffer1[BUFFER_SIZE], buffer2[BUFFER_SIZE];
  do {
    file1.read(buffer1, BUFFER_SIZE);
    file2.read(buffer2, BUFFER_SIZE);

    if ((file1.eof() && !file2.eof()) ||
        (!file1.eof() && file2.eof()) ||
        (file1.gcount() != file2.gcount()) ||
        (memcmp(buffer1, buffer2, file1.gcount()))) {
      file1.close();
      file2.close();
      return false;
    }
  } while (!file1.eof() && !file2.eof());

  file1.close();
  file2.close();
  return true;
}

bool ReadFileToString(const std::wstring& path, std::string* contents) {
  FILE* file = OpenFile(path, "rb");
  if (!file) {
    return false;
  }

  char buf[1 << 16];
  size_t len;
  while ((len = fread(buf, 1, sizeof(buf), file)) > 0) {
    contents->append(buf, len);
  }
  CloseFile(file);

  return true;
}

bool GetFileSize(const FilePath& file_path, int64* file_size) {
  FileInfo info;
  if (!GetFileInfo(file_path, &info))
    return false;
  *file_size = info.size;
  return true;
}

bool CloseFile(FILE* file) {
  if (file == NULL)
    return true;
  return fclose(file) == 0;
}

///////////////////////////////////////////////
// MemoryMappedFile

MemoryMappedFile::~MemoryMappedFile() {
  CloseHandles();
}

bool MemoryMappedFile::Initialize(const FilePath& file_name) {
  if (IsValid())
    return false;

  if (!MapFileToMemory(file_name)) {
    CloseHandles();
    return false;
  }

  return true;
}

bool MemoryMappedFile::IsValid() {
  return data_ != NULL;
}

// Deprecated functions ----------------------------------------------------

bool AbsolutePath(std::wstring* path_str) {
  FilePath path(FilePath::FromWStringHack(*path_str));
  if (!AbsolutePath(&path))
    return false;
  *path_str = path.ToWStringHack();
  return true;
}
void AppendToPath(std::wstring* path, const std::wstring& new_ending) {
  if (!path) {
    NOTREACHED();
    return;  // Don't crash in this function in release builds.
  }

  if (!EndsWithSeparator(path))
    path->push_back(FilePath::kSeparators[0]);
  path->append(new_ending);
}
bool CopyDirectory(const std::wstring& from_path, const std::wstring& to_path,
                   bool recursive) {
  return CopyDirectory(FilePath::FromWStringHack(from_path),
                       FilePath::FromWStringHack(to_path),
                       recursive);
}
bool ContentsEqual(const std::wstring& filename1,
                   const std::wstring& filename2) {
  return ContentsEqual(FilePath::FromWStringHack(filename1),
                       FilePath::FromWStringHack(filename2));
}
bool CopyFile(const std::wstring& from_path, const std::wstring& to_path) {
  return CopyFile(FilePath::FromWStringHack(from_path),
                  FilePath::FromWStringHack(to_path));
}
bool CreateDirectory(const std::wstring& full_path) {
  return CreateDirectory(FilePath::FromWStringHack(full_path));
}
bool CreateNewTempDirectory(const std::wstring& prefix,
                            std::wstring* new_temp_path) {
#if defined(OS_WIN)
  FilePath::StringType dir_prefix(prefix);
#elif defined(OS_POSIX)
  FilePath::StringType dir_prefix = WideToUTF8(prefix);
#endif
  FilePath temp_path;
  if (!CreateNewTempDirectory(dir_prefix, &temp_path))
    return false;
  *new_temp_path = temp_path.ToWStringHack();
  return true;
}
bool CreateTemporaryFileName(std::wstring* temp_file) {
  FilePath temp_file_path;
  if (!CreateTemporaryFileName(&temp_file_path))
    return false;
  *temp_file = temp_file_path.ToWStringHack();
  return true;
}
bool Delete(const std::wstring& path, bool recursive) {
  return Delete(FilePath::FromWStringHack(path), recursive);
}
bool DirectoryExists(const std::wstring& path) {
  return DirectoryExists(FilePath::FromWStringHack(path));
}
bool EndsWithSeparator(std::wstring* path) {
  return EndsWithSeparator(FilePath::FromWStringHack(*path));
}
bool EndsWithSeparator(const std::wstring& path) {
  return EndsWithSeparator(FilePath::FromWStringHack(path));
}
bool GetCurrentDirectory(std::wstring* path_str) {
  FilePath path;
  if (!GetCurrentDirectory(&path))
    return false;
  *path_str = path.ToWStringHack();
  return true;
}
bool GetFileInfo(const std::wstring& file_path, FileInfo* results) {
  return GetFileInfo(FilePath::FromWStringHack(file_path), results);
}
std::wstring GetFilenameFromPath(const std::wstring& path) {
  if (path.empty() || EndsWithSeparator(path))
    return std::wstring();

  return FilePath::FromWStringHack(path).BaseName().ToWStringHack();
}
bool GetFileSize(const std::wstring& file_path, int64* file_size) {
  return GetFileSize(FilePath::FromWStringHack(file_path), file_size);
}
bool GetTempDir(std::wstring* path_str) {
  FilePath path;
  if (!GetTempDir(&path))
    return false;
  *path_str = path.ToWStringHack();
  return true;
}
bool Move(const std::wstring& from_path, const std::wstring& to_path) {
  return Move(FilePath::FromWStringHack(from_path),
              FilePath::FromWStringHack(to_path));
}
FILE* OpenFile(const std::wstring& filename, const char* mode) {
  return OpenFile(FilePath::FromWStringHack(filename), mode);
}
bool PathExists(const std::wstring& path) {
  return PathExists(FilePath::FromWStringHack(path));
}
bool PathIsWritable(const std::wstring& path) {
  return PathIsWritable(FilePath::FromWStringHack(path));
}
bool SetCurrentDirectory(const std::wstring& directory) {
  return SetCurrentDirectory(FilePath::FromWStringHack(directory));
}
void TrimFilename(std::wstring* path) {
  if (EndsWithSeparator(path)) {
    TrimTrailingSeparator(path);
  } else {
    *path = FilePath::FromWStringHack(*path).DirName().ToWStringHack();
  }
}
void UpOneDirectory(std::wstring* dir) {
  FilePath path = FilePath::FromWStringHack(*dir);
  FilePath directory = path.DirName();
  // If there is no separator, we will get back kCurrentDirectory.
  // In this case don't change |dir|.
  if (directory.value() != FilePath::kCurrentDirectory)
    *dir = directory.ToWStringHack();
}
void UpOneDirectoryOrEmpty(std::wstring* dir) {
  FilePath path = FilePath::FromWStringHack(*dir);
  FilePath directory = path.DirName();
  // If there is no separator, we will get back kCurrentDirectory.
  // In this case, clear dir.
  if (directory == path || directory.value() == FilePath::kCurrentDirectory)
    dir->clear();
  else
    *dir = directory.ToWStringHack();
}
}  // namespace