webkit/fileapi/file_system_file_util.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_H_
   6 #define WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_H_
   7
   8 #include "base/file_path.h"
   9 #include "base/file_util_proxy.h"
  10 #include "base/memory/ref_counted.h"
  11 #include "base/platform_file.h"
  12 #include "webkit/fileapi/file_system_url.h"
  13 #include "webkit/fileapi/fileapi_export.h"
  14
  15 namespace base {
  16 class Time;
  17 }
  18
  19 namespace webkit_blob {
  20 class ShareableFileReference;
  21 }
  22
  23 namespace fileapi {
  24
  25 using base::PlatformFile;
  26 using base::PlatformFileError;
  27 class FileSystemOperationContext;
  28
  29 // A file utility interface that provides basic file utility methods for
  30 // FileSystem API.
  31 //
  32 // Layering structure of the FileSystemFileUtil was split out.
  33 // See http://crbug.com/128136 if you need it.
  34 class FILEAPI_EXPORT FileSystemFileUtil {
  35  public:
  36   // It will be implemented by each subclass such as FileSystemFileEnumerator.
  37   class AbstractFileEnumerator {
  38    public:
  39     virtual ~AbstractFileEnumerator() {}
  40
  41     // Returns an empty string if there are no more results.
  42     virtual FilePath Next() = 0;
  43
  44     virtual int64 Size() = 0;
  45     virtual base::Time LastModifiedTime() = 0;
  46     virtual bool IsDirectory() = 0;
  47   };
  48
  49   // A policy flag for CreateSnapshotFile.
  50   enum SnapshotFilePolicy {
  51     kSnapshotFileUnknown,
  52
  53     // The implementation just uses the local file as the snapshot file.
  54     // The FileAPI backend does nothing on the returned file.
  55     kSnapshotFileLocal,
  56
  57     // The implementation returns a temporary file as the snapshot file.
  58     // The FileAPI backend takes care of the lifetime of the returned file
  59     // and will delete when the last reference of the file is dropped.
  60     kSnapshotFileTemporary,
  61   };
  62
  63   class EmptyFileEnumerator : public AbstractFileEnumerator {
  64     virtual FilePath Next() OVERRIDE;
  65     virtual int64 Size() OVERRIDE;
  66     virtual base::Time LastModifiedTime() OVERRIDE;
  67     virtual bool IsDirectory() OVERRIDE;
  68   };
  69
  70   virtual ~FileSystemFileUtil() {}
  71
  72   // Creates or opens a file with the given flags.
  73   // If PLATFORM_FILE_CREATE is set in |file_flags| it always tries to create
  74   // a new file at the given |url| and calls back with
  75   // PLATFORM_FILE_ERROR_FILE_EXISTS if the |url| already exists.
  76   virtual PlatformFileError CreateOrOpen(
  77       FileSystemOperationContext* context,
  78       const FileSystemURL& url,
  79       int file_flags,
  80       PlatformFile* file_handle,
  81       bool* created) = 0;
  82
  83   // Closes the given file handle.
  84   virtual PlatformFileError Close(
  85       FileSystemOperationContext* context,
  86       PlatformFile file) = 0;
  87
  88   // Ensures that the given |url| exist.  This creates a empty new file
  89   // at |url| if the |url| does not exist.
  90   // If a new file han not existed and is created at the |url|,
  91   // |created| is set true and |error code|
  92   // is set PLATFORM_FILE_OK.
  93   // If the file already exists, |created| is set false and |error code|
  94   // is set PLATFORM_FILE_OK.
  95   // If the file hasn't existed but it couldn't be created for some other
  96   // reasons, |created| is set false and |error code| indicates the error.
  97   virtual PlatformFileError EnsureFileExists(
  98       FileSystemOperationContext* context,
  99       const FileSystemURL& url, bool* created) = 0;
 100
 101   // Creates directory at given url. It's an error to create
 102   // if |exclusive| is true and dir already exists.
 103   virtual PlatformFileError CreateDirectory(
 104       FileSystemOperationContext* context,
 105       const FileSystemURL& url,
 106       bool exclusive,
 107       bool recursive) = 0;
 108
 109   // Retrieves the information about a file.
 110   virtual PlatformFileError GetFileInfo(
 111       FileSystemOperationContext* context,
 112       const FileSystemURL& url,
 113       base::PlatformFileInfo* file_info,
 114       FilePath* platform_path) = 0;
 115
 116   // Returns a pointer to a new instance of AbstractFileEnumerator which is
 117   // implemented for each FileSystemFileUtil subclass. The instance needs to be
 118   // freed by the caller, and its lifetime should not extend past when the
 119   // current call returns to the main FILE message loop.
 120   //
 121   // The supplied context must remain valid at least lifetime of the enumerator
 122   // instance.
 123   virtual AbstractFileEnumerator* CreateFileEnumerator(
 124       FileSystemOperationContext* context,
 125       const FileSystemURL& root_url,
 126       bool recursive) = 0;
 127
 128   // Maps |file_system_url| given |context| into |local_file_path|
 129   // which represents physical file location on the host OS.
 130   // This may not always make sense for all subclasses.
 131   virtual PlatformFileError GetLocalFilePath(
 132       FileSystemOperationContext* context,
 133       const FileSystemURL& file_system_url,
 134       FilePath* local_file_path) = 0;
 135
 136   // Updates the file metadata information.  Unlike posix's touch, it does
 137   // not create a file even if |url| does not exist, but instead fails
 138   // with PLATFORM_FILE_ERROR_NOT_FOUND.
 139   virtual PlatformFileError Touch(
 140       FileSystemOperationContext* context,
 141       const FileSystemURL& url,
 142       const base::Time& last_access_time,
 143       const base::Time& last_modified_time) = 0;
 144
 145   // Truncates a file to the given length.  If |length| is greater than the
 146   // current length of the file, the file will be extended with zeroes.
 147   virtual PlatformFileError Truncate(
 148       FileSystemOperationContext* context,
 149       const FileSystemURL& url,
 150       int64 length) = 0;
 151
 152   // Returns true if a given |url| is an empty directory.
 153   virtual bool IsDirectoryEmpty(
 154       FileSystemOperationContext* context,
 155       const FileSystemURL& url) = 0;
 156
 157   // Copies or moves a single file from |src_url| to |dest_url|.
 158   virtual PlatformFileError CopyOrMoveFile(
 159       FileSystemOperationContext* context,
 160       const FileSystemURL& src_url,
 161       const FileSystemURL& dest_url,
 162       bool copy) = 0;
 163
 164   // Copies in a single file from a different filesystem.
 165   virtual PlatformFileError CopyInForeignFile(
 166         FileSystemOperationContext* context,
 167         const FilePath& src_file_path,
 168         const FileSystemURL& dest_url) = 0;
 169
 170   // Deletes a single file.
 171   // It assumes the given url points a file.
 172   virtual PlatformFileError DeleteFile(
 173       FileSystemOperationContext* context,
 174       const FileSystemURL& url) = 0;
 175
 176   // Deletes a single empty directory.
 177   // It assumes the given url points an empty directory.
 178   virtual PlatformFileError DeleteSingleDirectory(
 179       FileSystemOperationContext* context,
 180       const FileSystemURL& url) = 0;
 181
 182   // Creates a local snapshot file for a given |url| and returns the
 183   // metadata and platform path of the snapshot file via |callback|.
 184   // In regular filesystem cases the implementation may simply return
 185   // the metadata of the file itself (as well as GetMetadata does),
 186   // while in non-regular filesystem case the backend may create a
 187   // temporary snapshot file which holds the file data and return
 188   // the metadata of the temporary file.
 189   //
 190   // |file_info| is the metadata of the snapshot file created.
 191   // |platform_path| is the path to the snapshot file created.
 192   // |policy| should indicate the policy how the fileapi backend
 193   // should handle the returned file.
 194   virtual base::PlatformFileError CreateSnapshotFile(
 195       FileSystemOperationContext* context,
 196       const FileSystemURL& url,
 197       base::PlatformFileInfo* file_info,
 198       FilePath* platform_path,
 199       SnapshotFilePolicy* policy) = 0;
 200
 201  protected:
 202   FileSystemFileUtil() {}
 203
 204  private:
 205   DISALLOW_COPY_AND_ASSIGN(FileSystemFileUtil);
 206 };
 207
 208 }  // namespace fileapi
 209
 210 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_H_