chrome/browser/chromeos/policy/user_policy_disk_cache.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 CHROME_BROWSER_CHROMEOS_POLICY_USER_POLICY_DISK_CACHE_H_
   6 #define CHROME_BROWSER_CHROMEOS_POLICY_USER_POLICY_DISK_CACHE_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/files/file_path.h"
  10 #include "base/memory/ref_counted.h"
  11 #include "base/memory/weak_ptr.h"
  12
  13 namespace base {
  14 class SequencedTaskRunner;
  15 }
  16
  17 namespace enterprise_management {
  18 class CachedCloudPolicyResponse;
  19 }
  20
  21 namespace policy {
  22
  23 // Handles the on-disk cache file used by UserPolicyCache. This class handles
  24 // the necessary thread switching and may outlive the associated UserPolicyCache
  25 // instance.
  26 class UserPolicyDiskCache
  27     : public base::RefCountedThreadSafe<UserPolicyDiskCache> {
  28  public:
  29   // Indicates the status of a completed load operation.
  30   enum LoadResult {
  31     // Policy was loaded successfully.
  32     LOAD_RESULT_SUCCESS,
  33     // Cache file missing.
  34     LOAD_RESULT_NOT_FOUND,
  35     // Failed to read cache file.
  36     LOAD_RESULT_READ_ERROR,
  37     // Failed to parse cache file.
  38     LOAD_RESULT_PARSE_ERROR,
  39   };
  40
  41   // Delegate interface for observing loads operations.
  42   class Delegate {
  43    public:
  44     virtual ~Delegate();
  45     virtual void OnDiskCacheLoaded(
  46         LoadResult result,
  47         const enterprise_management::CachedCloudPolicyResponse& policy) = 0;
  48   };
  49
  50   UserPolicyDiskCache(
  51       const base::WeakPtr<Delegate>& delegate,
  52       const base::FilePath& backing_file_path,
  53       scoped_refptr<base::SequencedTaskRunner> background_task_runner);
  54
  55   // Starts reading the policy cache from disk. Passes the read policy
  56   // information back to the hosting UserPolicyCache after a successful cache
  57   // load through UserPolicyCache::OnDiskCacheLoaded().
  58   void Load();
  59
  60   // Triggers a write operation to the disk cache on the FILE thread.
  61   void Store(const enterprise_management::CachedCloudPolicyResponse& policy);
  62
  63  private:
  64   friend class base::RefCountedThreadSafe<UserPolicyDiskCache>;
  65   ~UserPolicyDiskCache();
  66
  67   // Tries to load the cache file on the FILE thread.
  68   void LoadOnFileThread();
  69
  70   // Forwards the result to the UI thread.
  71   void LoadDone(LoadResult result,
  72                 const enterprise_management::CachedCloudPolicyResponse& policy);
  73
  74   // Passes back the successfully read policy to the cache on the UI thread.
  75   void ReportResultOnUIThread(
  76       LoadResult result,
  77       const enterprise_management::CachedCloudPolicyResponse& policy);
  78
  79   // Saves a policy blob on the FILE thread.
  80   void StoreOnFileThread(
  81       const enterprise_management::CachedCloudPolicyResponse& policy);
  82
  83   base::WeakPtr<Delegate> delegate_;
  84   const base::FilePath backing_file_path_;
  85   scoped_refptr<base::SequencedTaskRunner> origin_task_runner_;
  86   scoped_refptr<base::SequencedTaskRunner> background_task_runner_;
  87
  88   DISALLOW_COPY_AND_ASSIGN(UserPolicyDiskCache);
  89 };
  90
  91 }  // namespace policy
  92
  93 #endif  // CHROME_BROWSER_CHROMEOS_POLICY_USER_POLICY_DISK_CACHE_H_