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 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 #ifndef CacheFileContextEvictor__h__

 #define CacheFileContextEvictor__h__

 #include "nsTArray.h"

 #include "nsCOMPtr.h"

 #include "nsAutoPtr.h"

 class nsIFile;

 class nsILoadContextInfo;

 namespace mozilla {

 namespace net {

 class CacheIndexIterator;

 struct CacheFileContextEvictorEntry

 {

   nsCOMPtr<nsILoadContextInfo> mInfo;

   PRTime                       mTimeStamp; // in milliseconds

   nsRefPtr<CacheIndexIterator> mIterator;

 };

 class CacheFileContextEvictor

 {

 public:

   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CacheFileContextEvictor)

   CacheFileContextEvictor();

   virtual ~CacheFileContextEvictor();

   nsresult Init(nsIFile *aCacheDirectory);

   // Returns number of contexts that are being evicted.

   uint32_t ContextsCount();

   // Start evicting given context.

   nsresult AddContext(nsILoadContextInfo *aLoadContextInfo);

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

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

   // to index's state.

   nsresult CacheIndexStateChanged();

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

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

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

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

   // evictor.

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

 private:

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

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

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

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

   nsresult PersistEvictionInfoToDisk(nsILoadContextInfo *aLoadContextInfo);

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

   // removed from the disk.

   nsresult RemoveEvictInfoFromDisk(nsILoadContextInfo *aLoadContextInfo);

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

   // after startup.

   nsresult LoadEvictInfoFromDisk();

   nsresult GetContextFile(nsILoadContextInfo *aLoadContextInfo,

                           nsIFile **_retval);

   void     CreateIterators();

   void     CloseIterators();

   void     StartEvicting();

   nsresult EvictEntries();

   // Whether eviction is in progress

   bool mEvicting;

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

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

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

   // update process finishes.

   bool mIndexIsUpToDate;

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

   // startup.

   static bool sDiskAlreadySearched;

   // Array of contexts being evicted.

   nsTArray<nsAutoPtr<CacheFileContextEvictorEntry> > mEntries;

   nsCOMPtr<nsIFile> mCacheDirectory;

   nsCOMPtr<nsIFile> mEntriesDir;

 };

 } // net

 } // mozilla

 #endif