tor-browser

The Tor Browser
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CacheFileContextEvictor.h (4119B)

      1 /* This Source Code Form is subject to the terms of the Mozilla Public
      2 * License, v. 2.0. If a copy of the MPL was not distributed with this
      3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      4 
      5 #ifndef CacheFileContextEvictor__h__
      6 #define CacheFileContextEvictor__h__
      7 
      8 #include "mozilla/UniquePtr.h"
      9 #include "nsCOMPtr.h"
     10 #include "nsString.h"
     11 #include "nsTArray.h"
     12 
     13 class nsIFile;
     14 class nsILoadContextInfo;
     15 
     16 namespace mozilla {
     17 namespace net {
     18 
     19 class CacheIndexIterator;
     20 
     21 struct CacheFileContextEvictorEntry {
     22  nsCOMPtr<nsILoadContextInfo> mInfo;
     23  bool mPinned = false;
     24  // Only one of mOrigin or mBaseDomain can be set at a time
     25  nsString mOrigin;       // Optional - for origin-based eviction
     26  nsString mBaseDomain;   // Optional - for domain-based eviction
     27  PRTime mTimeStamp = 0;  // in milliseconds
     28  RefPtr<CacheIndexIterator> mIterator;
     29 };
     30 
     31 class CacheFileContextEvictor {
     32 public:
     33  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CacheFileContextEvictor)
     34 
     35  CacheFileContextEvictor();
     36 
     37 private:
     38  virtual ~CacheFileContextEvictor();
     39 
     40 public:
     41  nsresult Init(nsIFile* aCacheDirectory);
     42  void Shutdown();
     43 
     44  // Returns number of contexts that are being evicted.
     45  uint32_t ContextsCount();
     46  // Start evicting given context and an origin, if not empty.
     47  nsresult AddContext(nsILoadContextInfo* aLoadContextInfo, bool aPinned,
     48                      const nsAString& aOrigin, const nsAString& aBaseDomain);
     49  // CacheFileIOManager calls this method when CacheIndex's state changes. We
     50  // check whether the index is up to date and start or stop evicting according
     51  // to index's state.
     52  void CacheIndexStateChanged();
     53  // CacheFileIOManager calls this method to check whether an entry file should
     54  // be considered as evicted. It returns true when there is a matching context
     55  // info to the given key and the last modified time of the entry file is
     56  // earlier than the time stamp of the time when the context was added to the
     57  // evictor.
     58  void WasEvicted(const nsACString& aKey, nsIFile* aFile,
     59                  bool* aEvictedAsPinned, bool* aEvictedAsNonPinned);
     60 
     61 private:
     62  // Writes information about eviction of the given context to the disk. This is
     63  // done for every context added to the evictor to be able to recover eviction
     64  // after a shutdown or crash. When the context file is found after startup, we
     65  // restore mTimeStamp from the last modified time of the file.
     66  nsresult PersistEvictionInfoToDisk(nsILoadContextInfo* aLoadContextInfo,
     67                                     bool aPinned, const nsAString& aOrigin,
     68                                     const nsAString& aBaseDomain);
     69  // Once we are done with eviction for the given context, the eviction info is
     70  // removed from the disk.
     71  nsresult RemoveEvictInfoFromDisk(nsILoadContextInfo* aLoadContextInfo,
     72                                   bool aPinned, const nsAString& aOrigin,
     73                                   const nsAString& aBaseDomain);
     74  // Tries to load all contexts from the disk. This method is called just once
     75  // after startup.
     76  nsresult LoadEvictInfoFromDisk();
     77  nsresult GetContextFile(nsILoadContextInfo* aLoadContextInfo, bool aPinned,
     78                          const nsAString& aOrigin,
     79                          const nsAString& aBaseDomain, nsIFile** _retval);
     80 
     81  void CreateIterators();
     82  void CloseIterators();
     83  void StartEvicting();
     84  void EvictEntries();
     85 
     86  // Whether eviction is in progress
     87  bool mEvicting{false};
     88  // Whether index is up to date. We wait with eviction until the index finishes
     89  // update process when it is outdated. NOTE: We also stop eviction in progress
     90  // when the index is found outdated, the eviction is restarted again once the
     91  // update process finishes.
     92  bool mIndexIsUpToDate{false};
     93  // Whether we already tried to restore unfinished jobs from previous run after
     94  // startup.
     95  static bool sDiskAlreadySearched;
     96  // Array of contexts being evicted.
     97  nsTArray<UniquePtr<CacheFileContextEvictorEntry>> mEntries;
     98  nsCOMPtr<nsIFile> mCacheDirectory;
     99  nsCOMPtr<nsIFile> mEntriesDir;
    100 };
    101 
    102 }  // namespace net
    103 }  // namespace mozilla
    104 
    105 #endif