text: // Copyright (c) 2012 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.
  
  #ifndef WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_H_
  #define WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_H_
  
  #include "base/files/file_path.h"
  #include "base/memory/scoped_ptr.h"
  #include "base/platform_file.h"
  #include "webkit/fileapi/file_snapshot_policy.h"
  #include "webkit/storage/webkit_storage_export.h"
  
  namespace base {
  class Time;
  }
  
  namespace fileapi {
  
  class FileSystemOperationContext;
  class FileSystemURL;
  
  // A file utility interface that provides basic file utility methods for
  // FileSystem API.
  //
  // Layering structure of the FileSystemFileUtil was split out.
  // See http://crbug.com/128136 if you need it.
  class WEBKIT_STORAGE_EXPORT FileSystemFileUtil {
   public:
    // It will be implemented by each subclass such as FileSystemFileEnumerator.
    class WEBKIT_STORAGE_EXPORT AbstractFileEnumerator {
     public:
      virtual ~AbstractFileEnumerator() {}
  
      // Returns an empty string if there are no more results.
      virtual base::FilePath Next() = 0;
  
      // These methods return metadata for the file most recently returned by
      // Next(). If Next() has never been called, or if Next() most recently
      // returned an empty string, then return the default values of 0,
      // "null time", and false, respectively.
      virtual int64 Size() = 0;
      virtual base::Time LastModifiedTime() = 0;
      virtual bool IsDirectory() = 0;
    };
  
    class WEBKIT_STORAGE_EXPORT EmptyFileEnumerator
        : public AbstractFileEnumerator {
      virtual base::FilePath Next() OVERRIDE;
      virtual int64 Size() OVERRIDE;
      virtual base::Time LastModifiedTime() OVERRIDE;
      virtual bool IsDirectory() OVERRIDE;
    };
  
    virtual ~FileSystemFileUtil() {}
  
    // Creates or opens a file with the given flags.
    // See header comments for AsyncFileUtil::CreateOrOpen() for more details.
    // This is used only by Pepper/NaCL File API.
    virtual base::PlatformFileError CreateOrOpen(
        FileSystemOperationContext* context,
        const FileSystemURL& url,
        int file_flags,
        base::PlatformFile* file_handle,
        bool* created) = 0;
  
    // Closes the given file handle.
    // This is used only for Pepper/NaCL File API.
    virtual base::PlatformFileError Close(
        FileSystemOperationContext* context,
        base::PlatformFile file) = 0;
  
    // Ensures that the given |url| exist.  This creates a empty new file
    // at |url| if the |url| does not exist.
    // See header comments for AsyncFileUtil::EnsureFileExists() for more details.
    virtual base::PlatformFileError EnsureFileExists(
        FileSystemOperationContext* context,
        const FileSystemURL& url, bool* created) = 0;
  
    // Creates directory at given url.
    // See header comments for AsyncFileUtil::CreateDirectory() for more details.
    virtual base::PlatformFileError CreateDirectory(
        FileSystemOperationContext* context,
        const FileSystemURL& url,
        bool exclusive,
        bool recursive) = 0;
  
    // Retrieves the information about a file.
    // See header comments for AsyncFileUtil::GetFileInfo() for more details.
    virtual base::PlatformFileError GetFileInfo(
        FileSystemOperationContext* context,
        const FileSystemURL& url,
        base::PlatformFileInfo* file_info,
        base::FilePath* platform_path) = 0;
  
    // Returns a pointer to a new instance of AbstractFileEnumerator which is
    // implemented for each FileSystemFileUtil subclass. The instance needs to be
    // freed by the caller, and its lifetime should not extend past when the
    // current call returns to the main FILE message loop.
    //
    // The supplied context must remain valid at least lifetime of the enumerator
    // instance.
    virtual scoped_ptr<AbstractFileEnumerator> CreateFileEnumerator(
        FileSystemOperationContext* context,
        const FileSystemURL& root_url) = 0;
  
    // Maps |file_system_url| given |context| into |local_file_path|
    // which represents physical file location on the host OS.
    // This may not always make sense for all subclasses.
    virtual base::PlatformFileError GetLocalFilePath(
        FileSystemOperationContext* context,
        const FileSystemURL& file_system_url,
        base::FilePath* local_file_path) = 0;
  
    // Updates the file metadata information.
    // See header comments for AsyncFileUtil::Touch() for more details.
    virtual base::PlatformFileError Touch(
        FileSystemOperationContext* context,
        const FileSystemURL& url,
        const base::Time& last_access_time,
        const base::Time& last_modified_time) = 0;
  
    // Truncates a file to the given length.
    // See header comments for AsyncFileUtil::Truncate() for more details.
    virtual base::PlatformFileError Truncate(
        FileSystemOperationContext* context,
        const FileSystemURL& url,
        int64 length) = 0;
  
    // Copies or moves a single file from |src_url| to |dest_url|.
    // The filesystem type of |src_url| and |dest_url| MUST be same.
    //
    // This returns:
    // - PLATFORM_FILE_ERROR_NOT_FOUND if |src_url|
    //   or the parent directory of |dest_url| does not exist.
    // - PLATFORM_FILE_ERROR_NOT_A_FILE if |src_url| exists but is not a file.
    // - PLATFORM_FILE_ERROR_INVALID_OPERATION if |dest_url| exists and
    //   is not a file.
    // - PLATFORM_FILE_ERROR_FAILED if |dest_url| does not exist and
    //   its parent path is a file.
    //
    virtual base::PlatformFileError CopyOrMoveFile(
        FileSystemOperationContext* context,
        const FileSystemURL& src_url,
        const FileSystemURL& dest_url,
        bool copy) = 0;
  
    // Copies in a single file from a different filesystem.
    // See header comments for AsyncFileUtil::CopyInForeignFile() for
    // more details.
    virtual base::PlatformFileError CopyInForeignFile(
          FileSystemOperationContext* context,
          const base::FilePath& src_file_path,
          const FileSystemURL& dest_url) = 0;
  
    // Deletes a single file.
    // See header comments for AsyncFileUtil::DeleteFile() for more details.
    virtual base::PlatformFileError DeleteFile(
        FileSystemOperationContext* context,
        const FileSystemURL& url) = 0;
  
    // Deletes a single empty directory.
    // See header comments for AsyncFileUtil::DeleteDirectory() for more details.
    virtual base::PlatformFileError DeleteDirectory(
        FileSystemOperationContext* context,
        const FileSystemURL& url) = 0;
  
    // Creates a local snapshot file for a given |url| and returns the
    // metadata and platform path of the snapshot file via |callback|.
    //
    // See header comments for AsyncFileUtil::CreateSnapshotFile() for
    // more details.
    virtual base::PlatformFileError CreateSnapshotFile(
        FileSystemOperationContext* context,
        const FileSystemURL& url,
        base::PlatformFileInfo* file_info,
        base::FilePath* platform_path,
        SnapshotFilePolicy* policy) = 0;
  
   protected:
    FileSystemFileUtil() {}
  
   private:
    DISALLOW_COPY_AND_ASSIGN(FileSystemFileUtil);
  };
  
  }  // namespace fileapi
  
  #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_H_
  