import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

netwerk/cache2/CacheFileContextEvictor.h

@@ -0,0 +1,96 @@
+/* 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;
+  bool                         mPinned;
+  PRTime                       mTimeStamp; // in milliseconds
+  RefPtr<CacheIndexIterator> mIterator;
+};
+
+class CacheFileContextEvictor
+{
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CacheFileContextEvictor)
+
+  CacheFileContextEvictor();
+
+private:
+  virtual ~CacheFileContextEvictor();
+
+public:
+  nsresult Init(nsIFile *aCacheDirectory);
+
+  // Returns number of contexts that are being evicted.
+  uint32_t ContextsCount();
+  // Start evicting given context.
+  nsresult AddContext(nsILoadContextInfo *aLoadContextInfo, bool aPinned);
+  // 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 *aEvictedAsPinned, bool *aEvictedAsNonPinned);
+
+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, bool aPinned);
+  // Once we are done with eviction for the given context, the eviction info is
+  // removed from the disk.
+  nsresult RemoveEvictInfoFromDisk(nsILoadContextInfo *aLoadContextInfo, bool aPinned);
+  // Tries to load all contexts from the disk. This method is called just once
+  // after startup.
+  nsresult LoadEvictInfoFromDisk();
+  nsresult GetContextFile(nsILoadContextInfo *aLoadContextInfo, bool aPinned,
+                          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;
+};
+
+} // namespace net
+} // namespace mozilla
+
+#endif