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      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 STORAGE_BROWSER_FILEAPI_FILE_SYSTEM_OPERATION_CONTEXT_H_
      6 #define STORAGE_BROWSER_FILEAPI_FILE_SYSTEM_OPERATION_CONTEXT_H_
      7 
      8 #include "base/files/file_path.h"
      9 #include "base/supports_user_data.h"
     10 #include "base/threading/thread_checker.h"
     11 #include "storage/browser/fileapi/task_runner_bound_observer_list.h"
     12 #include "storage/browser/storage_browser_export.h"
     13 #include "storage/common/quota/quota_types.h"
     14 
     15 namespace base {
     16 class SequencedTaskRunner;
     17 }
     18 
     19 namespace storage {
     20 
     21 class FileSystemContext;
     22 
     23 // A context class which is carried around by FileSystemOperation and
     24 // its delegated tasks. It is valid to reuse one context instance across
     25 // multiple operations as far as those operations are supposed to share
     26 // the same context (e.g. use the same task runner, share the quota etc).
     27 // Note that the remaining quota bytes (allowed_bytes_growth) may be
     28 // updated during the execution of write operations.
     29 class STORAGE_EXPORT_PRIVATE FileSystemOperationContext
     30     : public base::SupportsUserData {
     31  public:
     32   explicit FileSystemOperationContext(FileSystemContext* context);
     33 
     34   // Specifies |task_runner| which the operation is performed on.
     35   // The backend of |task_runner| must outlive the IO thread.
     36   FileSystemOperationContext(FileSystemContext* context,
     37                              base::SequencedTaskRunner* task_runner);
     38 
     39   virtual ~FileSystemOperationContext();
     40 
     41   FileSystemContext* file_system_context() const {
     42     return file_system_context_.get();
     43   }
     44 
     45   // Updates the current remaining quota.
     46   // This can be called to update the remaining quota during the operation.
     47   void set_allowed_bytes_growth(const int64& allowed_bytes_growth) {
     48     allowed_bytes_growth_ = allowed_bytes_growth;
     49   }
     50 
     51   // Returns the current remaining quota.
     52   int64 allowed_bytes_growth() const { return allowed_bytes_growth_; }
     53   storage::QuotaLimitType quota_limit_type() const { return quota_limit_type_; }
     54   base::SequencedTaskRunner* task_runner() const { return task_runner_.get(); }
     55 
     56   ChangeObserverList* change_observers() { return &change_observers_; }
     57   UpdateObserverList* update_observers() { return &update_observers_; }
     58 
     59   // Following setters should be called only on the same thread as the
     60   // FileSystemOperationContext is created (i.e. are not supposed be updated
     61   // after the context's passed onto other task runners).
     62   void set_change_observers(const ChangeObserverList& list) {
     63     DCHECK(setter_thread_checker_.CalledOnValidThread());
     64     change_observers_ = list;
     65   }
     66   void set_update_observers(const UpdateObserverList& list) {
     67     DCHECK(setter_thread_checker_.CalledOnValidThread());
     68     update_observers_ = list;
     69   }
     70   void set_quota_limit_type(storage::QuotaLimitType limit_type) {
     71     DCHECK(setter_thread_checker_.CalledOnValidThread());
     72     quota_limit_type_ = limit_type;
     73   }
     74 
     75  private:
     76   scoped_refptr<FileSystemContext> file_system_context_;
     77   scoped_refptr<base::SequencedTaskRunner> task_runner_;
     78 
     79   // The current remaining quota, used by ObfuscatedFileUtil.
     80   int64 allowed_bytes_growth_;
     81 
     82   // The current quota limit type, used by ObfuscatedFileUtil.
     83   storage::QuotaLimitType quota_limit_type_;
     84 
     85   // Observers attached to this context.
     86   ChangeObserverList change_observers_;
     87   UpdateObserverList update_observers_;
     88 
     89   // Used to check its setters are not called on arbitrary thread.
     90   base::ThreadChecker setter_thread_checker_;
     91 
     92   DISALLOW_COPY_AND_ASSIGN(FileSystemOperationContext);
     93 };
     94 
     95 }  // namespace storage
     96 
     97 #endif  // STORAGE_BROWSER_FILEAPI_FILE_SYSTEM_OPERATION_CONTEXT_H_
     98