The Tor Browser: netwerk/cache2/CacheFileContextEvictor.h@7e26c7da4463

     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/. */

     5 #ifndef CacheFileContextEvictor__h__

     6 #define CacheFileContextEvictor__h__

     8 #include "nsTArray.h"

     9 #include "nsCOMPtr.h"

    10 #include "nsAutoPtr.h"

    12 class nsIFile;

    13 class nsILoadContextInfo;

    15 namespace mozilla {

    16 namespace net {

    18 class CacheIndexIterator;

    20 struct CacheFileContextEvictorEntry

    21 {

    22   nsCOMPtr<nsILoadContextInfo> mInfo;

    23   PRTime                       mTimeStamp; // in milliseconds

    24   nsRefPtr<CacheIndexIterator> mIterator;

    25 };

    27 class CacheFileContextEvictor

    28 {

    29 public:

    30   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CacheFileContextEvictor)

    32   CacheFileContextEvictor();

    33   virtual ~CacheFileContextEvictor();

    35   nsresult Init(nsIFile *aCacheDirectory);

    37   // Returns number of contexts that are being evicted.

    38   uint32_t ContextsCount();

    39   // Start evicting given context.

    40   nsresult AddContext(nsILoadContextInfo *aLoadContextInfo);

    41   // CacheFileIOManager calls this method when CacheIndex's state changes. We

    42   // check whether the index is up to date and start or stop evicting according

    43   // to index's state.

    44   nsresult CacheIndexStateChanged();

    45   // CacheFileIOManager calls this method to check whether an entry file should

    46   // be considered as evicted. It returns true when there is a matching context

    47   // info to the given key and the last modified time of the entry file is

    48   // earlier than the time stamp of the time when the context was added to the

    49   // evictor.

    50   nsresult WasEvicted(const nsACString &aKey, nsIFile *aFile, bool *_retval);

    52 private:

    53   // Writes information about eviction of the given context to the disk. This is

    54   // done for every context added to the evictor to be able to recover eviction

    55   // after a shutdown or crash. When the context file is found after startup, we

    56   // restore mTimeStamp from the last modified time of the file.

    57   nsresult PersistEvictionInfoToDisk(nsILoadContextInfo *aLoadContextInfo);

    58   // Once we are done with eviction for the given context, the eviction info is

    59   // removed from the disk.

    60   nsresult RemoveEvictInfoFromDisk(nsILoadContextInfo *aLoadContextInfo);

    61   // Tries to load all contexts from the disk. This method is called just once

    62   // after startup.

    63   nsresult LoadEvictInfoFromDisk();

    64   nsresult GetContextFile(nsILoadContextInfo *aLoadContextInfo,

    65                           nsIFile **_retval);

    67   void     CreateIterators();

    68   void     CloseIterators();

    69   void     StartEvicting();

    70   nsresult EvictEntries();

    72   // Whether eviction is in progress

    73   bool mEvicting;

    74   // Whether index is up to date. We wait with eviction until the index finishes

    75   // update process when it is outdated. NOTE: We also stop eviction in progress

    76   // when the index is found outdated, the eviction is restarted again once the

    77   // update process finishes.

    78   bool mIndexIsUpToDate;

    79   // Whether we already tried to restore unfinished jobs from previous run after

    80   // startup.

    81   static bool sDiskAlreadySearched;

    82   // Array of contexts being evicted.

    83   nsTArray<nsAutoPtr<CacheFileContextEvictorEntry> > mEntries;

    84   nsCOMPtr<nsIFile> mCacheDirectory;

    85   nsCOMPtr<nsIFile> mEntriesDir;

    86 };

    88 } // net

    89 } // mozilla

    91 #endif

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