nsCacheEntry.h

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 *
 * 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 _nsCacheEntry_h_
#define _nsCacheEntry_h_

#include "nsICache.h"
#include "nsICacheEntryDescriptor.h"
#include "nsIThread.h"
#include "nsCacheMetaData.h"

#include "nspr.h"
#include "PLDHashTable.h"
#include "nsAutoPtr.h"
#include "nscore.h"
#include "nsCOMPtr.h"
#include "nsString.h"
#include "nsAString.h"

class nsCacheDevice;
class nsCacheMetaData;
class nsCacheRequest;
class nsCacheEntryDescriptor;

/******************************************************************************
 * nsCacheEntry
 *******************************************************************************/
class nsCacheEntry : public PRCList {
 public:
  nsCacheEntry(const nsACString& key, bool streamBased,
               nsCacheStoragePolicy storagePolicy);
  ~nsCacheEntry();

  static nsresult Create(const char* key, bool streamBased,
                         nsCacheStoragePolicy storagePolicy,
                         nsCacheDevice* device, nsCacheEntry** result);

  nsCString* Key() { return &mKey; }

  int32_t FetchCount() { return mFetchCount; }
  void SetFetchCount(int32_t count) { mFetchCount = count; }
  void Fetched();

  uint32_t LastFetched() { return mLastFetched; }
  void SetLastFetched(uint32_t lastFetched) { mLastFetched = lastFetched; }

  uint32_t LastModified() { return mLastModified; }
  void SetLastModified(uint32_t lastModified) { mLastModified = lastModified; }

  uint32_t ExpirationTime() { return mExpirationTime; }
  void SetExpirationTime(uint32_t expires) { mExpirationTime = expires; }

  uint32_t Size() { return mDataSize + mMetaData.Size() + mKey.Length(); }

  nsCacheDevice* CacheDevice() { return mCacheDevice; }
  void SetCacheDevice(nsCacheDevice* device) { mCacheDevice = device; }
  void SetCustomCacheDevice(nsCacheDevice* device) { mCustomDevice = device; }
  nsCacheDevice* CustomCacheDevice() { return mCustomDevice; }
  const char* GetDeviceID();

  /**
   * Data accessors
   */
  nsISupports* Data() { return mData; }
  void SetData(nsISupports* data);

  int64_t PredictedDataSize() { return mPredictedDataSize; }
  void SetPredictedDataSize(int64_t size) { mPredictedDataSize = size; }

  uint32_t DataSize() { return mDataSize; }
  void SetDataSize(uint32_t size) { mDataSize = size; }

  void TouchData();

  /**
   * Meta data accessors
   */
  const char* GetMetaDataElement(const char* key) {
    return mMetaData.GetElement(key);
  }
  nsresult SetMetaDataElement(const char* key, const char* value) {
    return mMetaData.SetElement(key, value);
  }
  nsresult VisitMetaDataElements(nsICacheMetaDataVisitor* visitor) {
    return mMetaData.VisitElements(visitor);
  }
  nsresult FlattenMetaData(char* buffer, uint32_t bufSize) {
    return mMetaData.FlattenMetaData(buffer, bufSize);
  }
  nsresult UnflattenMetaData(const char* buffer, uint32_t bufSize) {
    return mMetaData.UnflattenMetaData(buffer, bufSize);
  }
  uint32_t MetaDataSize() { return mMetaData.Size(); }

  void TouchMetaData();

  /**
   * Security Info accessors
   */
  nsISupports* SecurityInfo() { return mSecurityInfo; }
  void SetSecurityInfo(nsISupports* info) { mSecurityInfo = info; }

  // XXX enumerate MetaData method

  enum CacheEntryFlags {
    eStoragePolicyMask = 0x000000FF,
    eDoomedMask = 0x00000100,
    eEntryDirtyMask = 0x00000200,
    eDataDirtyMask = 0x00000400,
    eMetaDataDirtyMask = 0x00000800,
    eStreamDataMask = 0x00001000,
    eActiveMask = 0x00002000,
    eInitializedMask = 0x00004000,
    eValidMask = 0x00008000,
    eBindingMask = 0x00010000,
    ePrivateMask = 0x00020000
  };

  void MarkBinding() { mFlags |= eBindingMask; }
  void ClearBinding() { mFlags &= ~eBindingMask; }
  bool IsBinding() { return (mFlags & eBindingMask) != 0; }

  void MarkEntryDirty() { mFlags |= eEntryDirtyMask; }
  void MarkEntryClean() { mFlags &= ~eEntryDirtyMask; }
  void MarkDataDirty() { mFlags |= eDataDirtyMask; }
  void MarkDataClean() { mFlags &= ~eDataDirtyMask; }
  void MarkMetaDataDirty() { mFlags |= eMetaDataDirtyMask; }
  void MarkMetaDataClean() { mFlags &= ~eMetaDataDirtyMask; }
  void MarkStreamData() { mFlags |= eStreamDataMask; }
  void MarkValid() { mFlags |= eValidMask; }
  void MarkInvalid() { mFlags &= ~eValidMask; }
  void MarkPrivate() { mFlags |= ePrivateMask; }
  void MarkPublic() { mFlags &= ~ePrivateMask; }
  //    void MarkAllowedInMemory() { mFlags |=  eAllowedInMemoryMask; }
  //    void MarkAllowedOnDisk()   { mFlags |=  eAllowedOnDiskMask; }

  bool IsDoomed() { return (mFlags & eDoomedMask) != 0; }
  bool IsEntryDirty() { return (mFlags & eEntryDirtyMask) != 0; }
  bool IsDataDirty() { return (mFlags & eDataDirtyMask) != 0; }
  bool IsMetaDataDirty() { return (mFlags & eMetaDataDirtyMask) != 0; }
  bool IsStreamData() { return (mFlags & eStreamDataMask) != 0; }
  bool IsActive() { return (mFlags & eActiveMask) != 0; }
  bool IsInitialized() { return (mFlags & eInitializedMask) != 0; }
  bool IsValid() { return (mFlags & eValidMask) != 0; }
  bool IsInvalid() { return (mFlags & eValidMask) == 0; }
  bool IsInUse() {
    return IsBinding() ||
           !(PR_CLIST_IS_EMPTY(&mRequestQ) && PR_CLIST_IS_EMPTY(&mDescriptorQ));
  }
  bool IsNotInUse() { return !IsInUse(); }
  bool IsPrivate() { return (mFlags & ePrivateMask) != 0; }

  bool IsAllowedInMemory() {
    return (StoragePolicy() == nsICache::STORE_ANYWHERE) ||
           (StoragePolicy() == nsICache::STORE_IN_MEMORY);
  }

  bool IsAllowedOnDisk() {
    return !IsPrivate() && ((StoragePolicy() == nsICache::STORE_ANYWHERE) ||
                            (StoragePolicy() == nsICache::STORE_ON_DISK));
  }

  bool IsAllowedOffline() {
    return (StoragePolicy() == nsICache::STORE_OFFLINE);
  }

  nsCacheStoragePolicy StoragePolicy() {
    return (nsCacheStoragePolicy)(mFlags & eStoragePolicyMask);
  }

  void SetStoragePolicy(nsCacheStoragePolicy policy) {
    NS_ASSERTION(policy <= 0xFF, "too many bits in nsCacheStoragePolicy");
    mFlags &= ~eStoragePolicyMask;  // clear storage policy bits
    mFlags |= policy;
  }

  // methods for nsCacheService
  nsresult RequestAccess(nsCacheRequest* request,
                         nsCacheAccessMode* accessGranted);
  nsresult CreateDescriptor(nsCacheRequest* request,
                            nsCacheAccessMode accessGranted,
                            nsICacheEntryDescriptor** result);

  bool RemoveRequest(nsCacheRequest* request);
  bool RemoveDescriptor(nsCacheEntryDescriptor* descriptor, bool* doomEntry);

  void GetDescriptors(
      nsTArray<RefPtr<nsCacheEntryDescriptor> >& outDescriptors);

 private:
  friend class nsCacheEntryHashTable;
  friend class nsCacheService;

  void DetachDescriptors();

  // internal methods
  void MarkDoomed() { mFlags |= eDoomedMask; }
  void MarkStreamBased() { mFlags |= eStreamDataMask; }
  void MarkInitialized() { mFlags |= eInitializedMask; }
  void MarkActive() { mFlags |= eActiveMask; }
  void MarkInactive() { mFlags &= ~eActiveMask; }

  nsCString mKey;
  uint32_t mFetchCount;                 // 4
  uint32_t mLastFetched;                // 4
  uint32_t mLastModified;               // 4
  uint32_t mLastValidated;              // 4
  uint32_t mExpirationTime;             // 4
  uint32_t mFlags;                      // 4
  int64_t mPredictedDataSize;           // Size given by ContentLength.
  uint32_t mDataSize;                   // 4
  nsCacheDevice* mCacheDevice;          // 4
  nsCacheDevice* mCustomDevice;         // 4
  nsCOMPtr<nsISupports> mSecurityInfo;  //
  nsISupports* mData;                   // strong ref
  nsCOMPtr<nsIEventTarget> mEventTarget;
  nsCacheMetaData mMetaData;  // 4
  PRCList mRequestQ;          // 8
  PRCList mDescriptorQ;       // 8
};

/******************************************************************************
 * nsCacheEntryInfo
 *******************************************************************************/
class nsCacheEntryInfo : public nsICacheEntryInfo {
 public:
  NS_DECL_ISUPPORTS
  NS_DECL_NSICACHEENTRYINFO

  explicit nsCacheEntryInfo(nsCacheEntry* entry) : mCacheEntry(entry) {}

  void DetachEntry() { mCacheEntry = nullptr; }

 private:
  nsCacheEntry* mCacheEntry;

  virtual ~nsCacheEntryInfo() = default;
};

/******************************************************************************
 * nsCacheEntryHashTable
 *******************************************************************************/

struct nsCacheEntryHashTableEntry : public PLDHashEntryHdr {
  nsCacheEntry* cacheEntry;
};

class nsCacheEntryHashTable {
 public:
  nsCacheEntryHashTable();
  ~nsCacheEntryHashTable();

  void Init();
  void Shutdown();

  nsCacheEntry* GetEntry(const nsCString* key) const;
  nsresult AddEntry(nsCacheEntry* entry);
  void RemoveEntry(nsCacheEntry* entry);

  PLDHashTable::Iterator Iter();

 private:
  // PLDHashTable operation callbacks
  static PLDHashNumber HashKey(const void* key);

  static bool MatchEntry(const PLDHashEntryHdr* entry, const void* key);

  static void MoveEntry(PLDHashTable* table, const PLDHashEntryHdr* from,
                        PLDHashEntryHdr* to);

  static void ClearEntry(PLDHashTable* table, PLDHashEntryHdr* entry);

  static void Finalize(PLDHashTable* table);

  // member variables
  static const PLDHashTableOps ops;
  PLDHashTable table;
  bool initialized;

  static const uint32_t kInitialTableLength = 256;
};

#endif  // _nsCacheEntry_h_