text: // 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.
  
  // This file contains utility functions for dealing with the local
  // filesystem.
  
  #ifndef BASE_FILE_UTIL_H_
  #define BASE_FILE_UTIL_H_
  
  #include "build/build_config.h"
  
  #if defined(OS_WIN)
  #include <windows.h>
  #elif defined(OS_POSIX)
  // Keep the order as in fts(3): fts.h requires types defined in sys/types.h
  #include <sys/types.h>
  #include <sys/stat.h>
  #include <fts.h>
  #endif
  
  #include <stdio.h>
  
  #include <stack>
  #include <string>
  #include <vector>
  
  #include "base/basictypes.h"
  #include "base/file_path.h"
  #include "base/scoped_ptr.h"
  #include "base/string16.h"
  
  namespace base {
  class Time;
  }
  
  namespace file_util {
  
  //-----------------------------------------------------------------------------
  // Functions that operate purely on a path string w/o touching the filesystem:
  
  // Returns true if the given path ends with a path separator character.
  bool EndsWithSeparator(const FilePath& path);
  // These two versions are both deprecated. TODO(estade): remove them.
  bool EndsWithSeparator(std::wstring* path);
  bool EndsWithSeparator(const std::wstring& path);
  
  // Makes sure that |path| ends with a separator IFF path is a directory that
  // exists. Returns true if |path| is an existing directory, false otherwise.
  bool EnsureEndsWithSeparator(FilePath* path);
  
  // Modifies a string by trimming all trailing separators from the end.
  // Deprecated. FilePath does this automatically, and if it's constructed from a
  // path with a trailing separator, StripTrailingSeparators() may be used.
  void TrimTrailingSeparator(std::wstring* dir);
  
  // Strips the topmost directory from the end of 'dir'.  Assumes 'dir' does not
  // refer to a file.
  // If 'dir' is a root directory, return without change.
  // Deprecated. Use FilePath::DirName instead.
  void UpOneDirectory(std::wstring* dir);
  // Strips the topmost directory from the end of 'dir'.  Assumes 'dir' does not
  // refer to a file.
  // If 'dir' is a root directory, the result becomes empty string.
  // Deprecated. Use FilePath::DirName instead.
  void UpOneDirectoryOrEmpty(std::wstring* dir);
  
  // Returns the filename portion of 'path', without any leading \'s or /'s.
  // Deprecated. Use FilePath::BaseName instead.
  std::wstring GetFilenameFromPath(const std::wstring& path);
  
  // Deprecated compatibility function.  Use FilePath::Extension.
  FilePath::StringType GetFileExtensionFromPath(const FilePath& path);
  // Deprecated temporary compatibility function.
  std::wstring GetFileExtensionFromPath(const std::wstring& path);
  
  // Returns the directory component of a path, without the trailing
  // path separator, or an empty string on error. The function does not
  // check for the existence of the path, so if it is passed a directory
  // without the trailing \, it will interpret the last component of the
  // path as a file and chomp it. This does not support relative paths.
  // Examples:
  // path == "C:\pics\jojo.jpg",     returns "C:\pics"
  // path == "C:\Windows\system32\", returns "C:\Windows\system32"
  // path == "C:\Windows\system32",  returns "C:\Windows"
  std::wstring GetDirectoryFromPath(const std::wstring& path);
  
  // Appends new_ending to path, adding a separator between the two if necessary.
  void AppendToPath(std::wstring* path, const std::wstring& new_ending);
  
  // Convert provided relative path into an absolute path.  Returns false on
  // error. On POSIX, this function fails if the path does not exist.
  bool AbsolutePath(FilePath* path);
  // Deprecated temporary compatibility function.
  bool AbsolutePath(std::wstring* path);
  
  // Returns true if |parent| contains |child|. Both paths are converted to
  // absolute paths before doing the comparison.
  bool ContainsPath(const FilePath& parent, const FilePath& child);
  
  // Deprecated compatibility function.  Use FilePath::InsertBeforeExtension.
  void InsertBeforeExtension(FilePath* path, const FilePath::StringType& suffix);
  
  // Deprecated compatibility function.  Use FilePath::ReplaceExtension.
  void ReplaceExtension(FilePath* file_name,
                        const FilePath::StringType& extension);
  
  // Replaces characters in 'file_name' that are illegal for file names with
  // 'replace_char'. 'file_name' must not be a full or relative path, but just the
  // file name component. Any leading or trailing whitespace in 'file_name' is
  // removed.
  // Example:
  //   file_name == "bad:file*name?.txt", changed to: "bad-file-name-.txt" when
  //   'replace_char' is '-'.
  void ReplaceIllegalCharacters(std::wstring* file_name, int replace_char);
  
  // Returns true if file_name does not have any illegal character. The input
  // param has the same restriction as that for ReplaceIllegalCharacters.
  bool IsFilenameLegal(const string16& file_name);
  
  //-----------------------------------------------------------------------------
  // Functions that involve filesystem access or modification:
  
  // created on or after the given |file_time|.  Doesn't count ".." or ".".
  //
  // Note for POSIX environments: a file created before |file_time|
  // can be mis-detected as a newer file due to low precision of
  // timestmap of file creation time. If you need to avoid such
  // mis-detection perfectly, you should wait one second before
  // obtaining |file_time|.
  int CountFilesCreatedAfter(const FilePath& path,
                             const base::Time& file_time);
  
  // Deletes the given path, whether it's a file or a directory.
  // If it's a directory, it's perfectly happy to delete all of the
  // directory's contents.  Passing true to recursive deletes
  // subdirectories and their contents as well.
  // Returns true if successful, false otherwise.
  //
  // WARNING: USING THIS WITH recursive==true IS EQUIVALENT
  //          TO "rm -rf", SO USE WITH CAUTION.
  bool Delete(const FilePath& path, bool recursive);
  // Deprecated temporary compatibility function.
  bool Delete(const std::wstring& path, bool recursive);
  
  // Moves the given path, whether it's a file or a directory.
  // If a simple rename is not possible, such as in the case where the paths are
  // on different volumes, this will attempt to copy and delete. Returns
  // true for success.
  bool Move(const FilePath& from_path, const FilePath& to_path);
  // Deprecated temporary compatibility function.
  bool Move(const std::wstring& from_path, const std::wstring& to_path);
  
  // Renames file |from_path| to |to_path|. Both paths must be on the same
  // volume, or the function will fail. Destination file will be created
  // if it doesn't exist. Prefer this function over Move when dealing with
  // temporary files. On Windows it preserves attributes of the target file.
  // Returns true on success.
  bool ReplaceFile(const FilePath& from_path, const FilePath& to_path);
  
  // Copies a single file. Use CopyDirectory to copy directories.
  bool CopyFile(const FilePath& from_path, const FilePath& to_path);
  // Deprecated temporary compatibility function.
  bool CopyFile(const std::wstring& from_path, const std::wstring& to_path);
  
  // Copies the given path, and optionally all subdirectories and their contents
  // as well.
  // If there are files existing under to_path, always overwrite.
  // Returns true if successful, false otherwise.
  // Don't use wildcards on the names, it may stop working without notice.
  //
  // If you only need to copy a file use CopyFile, it's faster.
  bool CopyDirectory(const FilePath& from_path, const FilePath& to_path,
                     bool recursive);
  // Deprecated temporary compatibility function.
  bool CopyDirectory(const std::wstring& from_path, const std::wstring& to_path,
                     bool recursive);
  
  // Returns true if the given path exists on the local filesystem,
  // false otherwise.
  bool PathExists(const FilePath& path);
  // Deprecated temporary compatibility function.
  bool PathExists(const std::wstring& path);
  
  // Returns true if the given path is writable by the user, false otherwise.
  bool PathIsWritable(const FilePath& path);
  // Deprecated temporary compatibility function.
  bool PathIsWritable(const std::wstring& path);
  
  // Returns true if the given path exists and is a directory, false otherwise.
  bool DirectoryExists(const FilePath& path);
  // Deprecated temporary compatibility function.
  bool DirectoryExists(const std::wstring& path);
  
  #if defined(OS_WIN)
  // Gets the creation time of the given file (expressed in the local timezone),
  // and returns it via the creation_time parameter.  Returns true if successful,
  // false otherwise.
  bool GetFileCreationLocalTime(const std::wstring& filename,
                                LPSYSTEMTIME creation_time);
  
  // Same as above, but takes a previously-opened file handle instead of a name.
  bool GetFileCreationLocalTimeFromHandle(HANDLE file_handle,
                                          LPSYSTEMTIME creation_time);
  #endif  // defined(OS_WIN)
  
  // Returns true if the contents of the two files given are equal, false
  // otherwise.  If either file can't be read, returns false.
  bool ContentsEqual(const FilePath& filename1,
                     const FilePath& filename2);
  // Deprecated temporary compatibility function.
  bool ContentsEqual(const std::wstring& filename1,
                     const std::wstring& filename2);
  
  // Returns true if the contents of the two text files given are equal, false
  // otherwise.  This routine treats "\r\n" and "\n" as equivalent.
  bool TextContentsEqual(const FilePath& filename1, const FilePath& filename2);
  
  // Read the file at |path| into |contents|, returning true on success.
  // Useful for unit tests.
  bool ReadFileToString(const FilePath& path, std::string* contents);
  // Deprecated version.
  bool ReadFileToString(const std::wstring& path, std::string* contents);
  
  #if defined(OS_POSIX)
  // Read exactly |bytes| bytes from file descriptor |fd|, storing the result
  // in |buffer|. This function is protected against EINTR and partial reads.
  // Returns true iff |bytes| bytes have been successfuly read from |fd|.
  bool ReadFromFD(int fd, char* buffer, size_t bytes);
  #endif  // defined(OS_POSIX)
  
  #if defined(OS_WIN)
  // Resolve Windows shortcut (.LNK file)
  // Argument path specifies a valid LNK file. On success, return true and put
  // the URL into path. If path is a invalid .LNK file, return false.
  bool ResolveShortcut(FilePath* path);
  // Deprecated temporary compatibility function.
  bool ResolveShortcut(std::wstring* path);
  
  // Create a Windows shortcut (.LNK file)
  // This method creates a shortcut link using the information given. Ensure
  // you have initialized COM before calling into this function. 'source'
  // and 'destination' parameters are required, everything else can be NULL.
  // 'source' is the existing file, 'destination' is the new link file to be
  // created; for best results pass the filename with the .lnk extension.
  // The 'icon' can specify a dll or exe in which case the icon index is the
  // resource id.
  // Note that if the shortcut exists it will overwrite it.
  bool CreateShortcutLink(const wchar_t *source, const wchar_t *destination,
                          const wchar_t *working_dir, const wchar_t *arguments,
                          const wchar_t *description, const wchar_t *icon,
                          int icon_index);
  
  // Update a Windows shortcut (.LNK file). This method assumes the shortcut
  // link already exists (otherwise false is returned). Ensure you have
  // initialized COM before calling into this function. Only 'destination'
  // parameter is required, everything else can be NULL (but if everything else
  // is NULL no changes are made to the shortcut). 'destination' is the link
  // file to be updated. For best results pass the filename with the .lnk
  // extension.
  bool UpdateShortcutLink(const wchar_t *source, const wchar_t *destination,
                          const wchar_t *working_dir, const wchar_t *arguments,
                          const wchar_t *description, const wchar_t *icon,
                          int icon_index);
  
  // Return true if the given directory is empty
  bool IsDirectoryEmpty(const std::wstring& dir_path);
  
  // Copy from_path to to_path recursively and then delete from_path recursively.
  // Returns true if all operations succeed.
  // This function simulates Move(), but unlike Move() it works across volumes.
  // This fuction is not transactional.
  bool CopyAndDeleteDirectory(const FilePath& from_path,
                              const FilePath& to_path);
  #endif
  
  // Get the temporary directory provided by the system.
  bool GetTempDir(FilePath* path);
  // Deprecated temporary compatibility function.
  bool GetTempDir(std::wstring* path);
  // Get a temporary directory for shared memory files.
  // Only useful on POSIX; redirects to GetTempDir() on Windows.
  bool GetShmemTempDir(FilePath* path);
  
  // Creates a temporary file. The full path is placed in |path|, and the
  // function returns true if was successful in creating the file. The file will
  // be empty and all handles closed after this function returns.
  // TODO(erikkay): rename this function and track down all of the callers.
  // (Clarification of erik's comment: the intent is to rename the BlahFileName()
  //  calls into BlahFile(), since they create temp files (not temp filenames).)
  bool CreateTemporaryFileName(FilePath* path);
  // Deprecated temporary compatibility function.
  bool CreateTemporaryFileName(std::wstring* temp_file);
  
  // Create and open a temporary file.  File is opened for read/write.
  // The full path is placed in |path|, and the function returns true if
  // was successful in creating and opening the file.
  FILE* CreateAndOpenTemporaryFile(FilePath* path);
  // Like above but for shmem files.  Only useful for POSIX.
  FILE* CreateAndOpenTemporaryShmemFile(FilePath* path);
  
  // Similar to CreateAndOpenTemporaryFile, but the file is created in |dir|.
  FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir, FilePath* path);
  
  // Same as CreateTemporaryFileName but the file is created in |dir|.
  bool CreateTemporaryFileNameInDir(const std::wstring& dir,
                                    std::wstring* temp_file);
  
  // Create a new directory under TempPath. If prefix is provided, the new
  // directory name is in the format of prefixyyyy.
  // NOTE: prefix is ignored in the POSIX implementation.
  // TODO(erikkay): is this OK?
  // If success, return true and output the full path of the directory created.
  bool CreateNewTempDirectory(const FilePath::StringType& prefix,
                              FilePath* new_temp_path);
  // Deprecated temporary compatibility function.
  bool CreateNewTempDirectory(const std::wstring& prefix,
                              std::wstring* new_temp_path);
  
  // Creates a directory, as well as creating any parent directories, if they
  // don't exist. Returns 'true' on successful creation, or if the directory
  // already exists.  The directory is only readable by the current user.
  bool CreateDirectory(const FilePath& full_path);
  // Deprecated temporary compatibility function.
  bool CreateDirectory(const std::wstring& full_path);
  
  // Returns the file size. Returns true on success.
  bool GetFileSize(const FilePath& file_path, int64* file_size);
  // Deprecated temporary compatibility function.
  bool GetFileSize(const std::wstring& file_path, int64* file_size);
  
  // Used to hold information about a given file path.  See GetFileInfo below.
  struct FileInfo {
    // The size of the file in bytes.  Undefined when is_directory is true.
    int64 size;
  
    // True if the file corresponds to a directory.
    bool is_directory;
  
    // Add additional fields here as needed.
  };
  
  // Returns information about the given file path.
  bool GetFileInfo(const FilePath& file_path, FileInfo* info);
  // Deprecated temporary compatibility function.
  bool GetFileInfo(const std::wstring& file_path, FileInfo* info);
  
  #if defined(OS_POSIX)
  // Store inode number of |path| in |inode|. Return true on success.
  bool GetInode(const FilePath& path, ino_t* inode);
  #endif
  
  // Wrapper for fopen-like calls. Returns non-NULL FILE* on success.
  FILE* OpenFile(const FilePath& filename, const char* mode);
  // Deprecated temporary compatibility functions.
  FILE* OpenFile(const std::string& filename, const char* mode);
  FILE* OpenFile(const std::wstring& filename, const char* mode);
  
  // Closes file opened by OpenFile. Returns true on success.
  bool CloseFile(FILE* file);
  
  // Truncates an open file to end at the location of the current file pointer.
  // This is a cross-platform analog to Windows' SetEndOfFile() function.
  bool TruncateFile(FILE* file);
  
  // Reads the given number of bytes from the file into the buffer.  Returns
  // the number of read bytes, or -1 on error.
  int ReadFile(const FilePath& filename, char* data, int size);
  // Deprecated temporary compatibility function.
  int ReadFile(const std::wstring& filename, char* data, int size);
  
  // Writes the given buffer into the file, overwriting any data that was
  // previously there.  Returns the number of bytes written, or -1 on error.
  int WriteFile(const FilePath& filename, const char* data, int size);
  // Deprecated temporary compatibility function.
  int WriteFile(const std::wstring& filename, const char* data, int size);
  
  // Gets the current working directory for the process.
  bool GetCurrentDirectory(FilePath* path);
  // Deprecated temporary compatibility function.
  bool GetCurrentDirectory(std::wstring* path);
  
  // Sets the current working directory for the process.
  bool SetCurrentDirectory(const FilePath& path);
  // Deprecated temporary compatibility function.
  bool SetCurrentDirectory(const std::wstring& current_directory);
  
  // A class to handle auto-closing of FILE*'s.
  class ScopedFILEClose {
   public:
    inline void operator()(FILE* x) const {
      if (x) {
        fclose(x);
      }
    }
  };
  
  typedef scoped_ptr_malloc<FILE, ScopedFILEClose> ScopedFILE;
  
  // A class for enumerating the files in a provided path. The order of the
  // results is not guaranteed.
  //
  // DO NOT USE FROM THE MAIN THREAD of your application unless it is a test
  // program where latency does not matter. This class is blocking.
  class FileEnumerator {
   public:
  #if defined(OS_WIN)
    typedef WIN32_FIND_DATA FindInfo;
  #elif defined(OS_POSIX)
    typedef struct {
      struct stat stat;
      std::string filename;
    } FindInfo;
  #endif
  
    enum FILE_TYPE {
      FILES                 = 1 << 0,
      DIRECTORIES           = 1 << 1,
      INCLUDE_DOT_DOT       = 1 << 2,
    };
  
    // |root_path| is the starting directory to search for. It may or may not end
    // in a slash.
    //
    // If |recursive| is true, this will enumerate all matches in any
    // subdirectories matched as well. It does a breadth-first search, so all
    // files in one directory will be returned before any files in a
    // subdirectory.
    //
    // |file_type| specifies whether the enumerator should match files,
    // directories, or both.
    //
    // |pattern| is an optional pattern for which files to match. This
    // works like shell globbing. For example, "*.txt" or "Foo???.doc".
    // However, be careful in specifying patterns that aren't cross platform
    // since the underlying code uses OS-specific matching routines.  In general,
    // Windows matching is less featureful than others, so test there first.
    // If unspecified, this will match all files.
    // NOTE: the pattern only matches the contents of root_path, not files in
    // recursive subdirectories.
    // TODO(erikkay): Fix the pattern matching to work at all levels.
    FileEnumerator(const FilePath& root_path,
                   bool recursive,
                   FileEnumerator::FILE_TYPE file_type);
    FileEnumerator(const FilePath& root_path,
                   bool recursive,
                   FileEnumerator::FILE_TYPE file_type,
                   const FilePath::StringType& pattern);
    ~FileEnumerator();
  
    // Returns an empty string if there are no more results.
    FilePath Next();
  
    // Write the file info into |info|.
    void GetFindInfo(FindInfo* info);
  
   private:
    FilePath root_path_;
    bool recursive_;
    FILE_TYPE file_type_;
    FilePath pattern_;  // Empty when we want to find everything.
  
    // Set to true when there is a find operation open. This way, we can lazily
    // start the operations when the caller calls Next().
    bool is_in_find_op_;
  
    // A stack that keeps track of which subdirectories we still need to
    // enumerate in the breadth-first search.
    std::stack<FilePath> pending_paths_;
  
    // Returns true if the given path should be skipped in enumeration.
    bool ShouldSkip(const FilePath& path);
  
    // Returns true if the given path's base name is ".".
    bool IsDot(const FilePath& path);
  
    // Returns true if the given path's base name is "..".
    bool IsDotDot(const FilePath& path);
  
  #if defined(OS_WIN)
    WIN32_FIND_DATA find_data_;
    HANDLE find_handle_;
  #elif defined(OS_POSIX)
    FTS* fts_;
    FTSENT* fts_ent_;
  #endif
  
    DISALLOW_EVIL_CONSTRUCTORS(FileEnumerator);
  };
  
  class MemoryMappedFile {
   public:
    // The default constructor sets all members to invalid/null values.
    MemoryMappedFile();
    ~MemoryMappedFile();
  
    // Opens an existing file and maps it into memory. Access is restricted to
    // read only. If this object already points to a valid memory mapped file
    // then this method will fail and return false. If it cannot open the file,
    // the file does not exist, or the memory mapping fails, it will return false.
    // Later we may want to allow the user to specify access.
    bool Initialize(const FilePath& file_name);
  
    const uint8* data() const { return data_; }
    size_t length() const { return length_; }
  
    // Is file_ a valid file handle that points to an open, memory mapped file?
    bool IsValid();
  
   private:
    // Map the file to memory, set data_ to that memory address. Return true on
    // success, false on any kind of failure. This is a helper for Initialize().
    bool MapFileToMemory(const FilePath& file_name);
  
    // Closes all open handles. Later we may want to make this public.
    void CloseHandles();
  
  #if defined(OS_WIN)
    HANDLE file_;
    HANDLE file_mapping_;
  #elif defined(OS_POSIX)
    // The file descriptor.
    int file_;
  #endif
    uint8* data_;
    size_t length_;
  
    DISALLOW_COPY_AND_ASSIGN(MemoryMappedFile);
  };
  
  // Renames a file using the SHFileOperation API to ensure that the target file
  // gets the correct default security descriptor in the new path.
  bool RenameFileAndResetSecurityDescriptor(
      const FilePath& source_file_path,
      const FilePath& target_file_path);
  
  }  // namespace file_util
  
  #endif  // BASE_FILE_UTIL_H_
  