webkit/fileapi/file_system_directory_database.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_DIRECTORY_DATABASE_H_
   6 #define WEBKIT_FILEAPI_FILE_SYSTEM_DIRECTORY_DATABASE_H_
   7
   8 #include <string>
   9 #include <vector>
  10
  11 #include "base/files/file_path.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/time.h"
  14 #include "webkit/storage/webkit_storage_export.h"
  15
  16 namespace tracked_objects {
  17 class Location;
  18 }
  19
  20 namespace leveldb {
  21 class DB;
  22 class Status;
  23 class WriteBatch;
  24 }
  25
  26 namespace fileapi {
  27
  28 // This class WILL NOT protect you against producing directory loops, giving an
  29 // empty directory a backing data file, giving two files the same backing file,
  30 // or pointing to a nonexistent backing file.  It does no file IO other than
  31 // that involved with talking to its underlying database.  It does not create or
  32 // in any way touch real files; it only creates path entries in its database.
  33
  34 // TODO(ericu): Safe mode, which does more checks such as the above on debug
  35 // builds.
  36 // TODO(ericu): Add a method that will give a unique filename for a data file.
  37 class WEBKIT_STORAGE_EXPORT_PRIVATE FileSystemDirectoryDatabase {
  38  public:
  39   typedef int64 FileId;
  40
  41   struct WEBKIT_STORAGE_EXPORT_PRIVATE FileInfo {
  42     FileInfo();
  43     ~FileInfo();
  44
  45     bool is_directory() const {
  46       return data_path.empty();
  47     }
  48
  49     FileId parent_id;
  50     base::FilePath data_path;
  51     base::FilePath::StringType name;
  52     // This modification time is valid only for directories, not files, as
  53     // FileWriter will get the files out of sync.
  54     // For files, look at the modification time of the underlying data_path.
  55     base::Time modification_time;
  56   };
  57
  58   explicit FileSystemDirectoryDatabase(
  59       const base::FilePath& filesystem_data_directory);
  60   ~FileSystemDirectoryDatabase();
  61
  62   bool GetChildWithName(
  63       FileId parent_id, const base::FilePath::StringType& name, FileId* child_id);
  64   bool GetFileWithPath(const base::FilePath& path, FileId* file_id);
  65   // ListChildren will succeed, returning 0 children, if parent_id doesn't
  66   // exist.
  67   bool ListChildren(FileId parent_id, std::vector<FileId>* children);
  68   bool GetFileInfo(FileId file_id, FileInfo* info);
  69   bool AddFileInfo(const FileInfo& info, FileId* file_id);
  70   bool RemoveFileInfo(FileId file_id);
  71   // This does a full update of the FileInfo, and is what you'd use for moves
  72   // and renames.  If you just want to update the modification_time, use
  73   // UpdateModificationTime.
  74   bool UpdateFileInfo(FileId file_id, const FileInfo& info);
  75   bool UpdateModificationTime(
  76       FileId file_id, const base::Time& modification_time);
  77   // This is used for an overwriting move of a file [not a directory] on top of
  78   // another file [also not a directory]; we need to alter two files' info in a
  79   // single transaction to avoid weird backing file references in the event of a
  80   // partial failure.
  81   bool OverwritingMoveFile(FileId src_file_id, FileId dest_file_id);
  82
  83   // This produces the series 0, 1, 2..., starting at 0 when the underlying
  84   // filesystem is first created, and maintaining state across
  85   // creation/destruction of FileSystemDirectoryDatabase objects.
  86   bool GetNextInteger(int64* next);
  87
  88   // Returns true if the database looks consistent with local filesystem.
  89   bool IsFileSystemConsistent();
  90
  91   static bool DestroyDatabase(const base::FilePath& path);
  92
  93  private:
  94   enum RecoveryOption {
  95     DELETE_ON_CORRUPTION,
  96     REPAIR_ON_CORRUPTION,
  97     FAIL_ON_CORRUPTION,
  98   };
  99
 100   friend class FileSystemDirectoryDatabaseTest;
 101
 102   bool Init(RecoveryOption recovery_option);
 103   bool RepairDatabase(const std::string& db_path);
 104   void ReportInitStatus(const leveldb::Status& status);
 105   bool StoreDefaultValues();
 106   bool GetLastFileId(FileId* file_id);
 107   bool VerifyIsDirectory(FileId file_id);
 108   bool AddFileInfoHelper(
 109       const FileInfo& info, FileId file_id, leveldb::WriteBatch* batch);
 110   bool RemoveFileInfoHelper(FileId file_id, leveldb::WriteBatch* batch);
 111   void HandleError(const tracked_objects::Location& from_here,
 112                    const leveldb::Status& status);
 113
 114   const base::FilePath filesystem_data_directory_;
 115   scoped_ptr<leveldb::DB> db_;
 116   base::Time last_reported_time_;
 117   DISALLOW_COPY_AND_ASSIGN(FileSystemDirectoryDatabase);
 118 };
 119
 120 }  // namespace fileapi
 121
 122 #endif  // WEBKIT_FILEAPI_FILE_SYSTEM_DIRECTORY_DATABASE_H_