import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

netwerk/cache2/CacheEntry.h

@@ -0,0 +1,418 @@
+/* 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 CacheEntry__h__
+#define CacheEntry__h__
+
+#include "nsICacheEntry.h"
+#include "CacheFile.h"
+
+#include "nsIRunnable.h"
+#include "nsIOutputStream.h"
+#include "nsICacheEntryOpenCallback.h"
+#include "nsICacheEntryDoomCallback.h"
+
+#include "nsCOMPtr.h"
+#include "nsRefPtrHashtable.h"
+#include "nsDataHashtable.h"
+#include "nsHashKeys.h"
+#include "nsString.h"
+#include "nsCOMArray.h"
+#include "nsThreadUtils.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/TimeStamp.h"
+
+static inline uint32_t
+PRTimeToSeconds(PRTime t_usec)
+{
+  PRTime usec_per_sec = PR_USEC_PER_SEC;
+  return uint32_t(t_usec /= usec_per_sec);
+}
+
+#define NowInSeconds() PRTimeToSeconds(PR_Now())
+
+class nsIOutputStream;
+class nsIURI;
+class nsIThread;
+
+namespace mozilla {
+namespace net {
+
+class CacheStorageService;
+class CacheStorage;
+class CacheOutputCloseListener;
+class CacheEntryHandle;
+
+class CacheEntry final : public nsICacheEntry
+                       , public nsIRunnable
+                       , public CacheFileListener
+{
+public:
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSICACHEENTRY
+  NS_DECL_NSIRUNNABLE
+
+  CacheEntry(const nsACString& aStorageID, const nsACString& aURI, const nsACString& aEnhanceID,
+             bool aUseDisk, bool aSkipSizeCheck, bool aPin);
+
+  void AsyncOpen(nsICacheEntryOpenCallback* aCallback, uint32_t aFlags);
+
+  CacheEntryHandle* NewHandle();
+  // For a new and recreated entry w/o a callback, we need to wrap it
+  // with a handle to detect writing consumer is gone.
+  CacheEntryHandle* NewWriteHandle();
+
+public:
+  uint32_t GetMetadataMemoryConsumption();
+  nsCString const &GetStorageID() const { return mStorageID; }
+  nsCString const &GetEnhanceID() const { return mEnhanceID; }
+  nsCString const &GetURI() const { return mURI; }
+  // Accessible at any time
+  bool IsUsingDisk() const { return mUseDisk; }
+  bool IsReferenced() const;
+  bool IsFileDoomed();
+  bool IsDoomed() const { return mIsDoomed; }
+  bool IsPinned() const { return mPinned; }
+
+  // Methods for entry management (eviction from memory),
+  // called only on the management thread.
+
+  // TODO make these inline
+  double GetFrecency() const;
+  uint32_t GetExpirationTime() const;
+  uint32_t UseCount() const { return mUseCount; }
+
+  bool IsRegistered() const;
+  bool CanRegister() const;
+  void SetRegistered(bool aRegistered);
+
+  TimeStamp const& LoadStart() const { return mLoadStart; }
+
+  enum EPurge {
+    PURGE_DATA_ONLY_DISK_BACKED,
+    PURGE_WHOLE_ONLY_DISK_BACKED,
+    PURGE_WHOLE,
+  };
+
+  bool DeferOrBypassRemovalOnPinStatus(bool aPinned);
+  bool Purge(uint32_t aWhat);
+  void PurgeAndDoom();
+  void DoomAlreadyRemoved();
+
+  nsresult HashingKeyWithStorage(nsACString &aResult) const;
+  nsresult HashingKey(nsACString &aResult) const;
+
+  static nsresult HashingKey(nsCSubstring const& aStorageID,
+                             nsCSubstring const& aEnhanceID,
+                             nsIURI* aURI,
+                             nsACString &aResult);
+
+  static nsresult HashingKey(nsCSubstring const& aStorageID,
+                             nsCSubstring const& aEnhanceID,
+                             nsCSubstring const& aURISpec,
+                             nsACString &aResult);
+
+  // Accessed only on the service management thread
+  double mFrecency;
+  ::mozilla::Atomic<uint32_t, ::mozilla::Relaxed> mSortingExpirationTime;
+
+  // Memory reporting
+  size_t SizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
+  size_t SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
+
+private:
+  virtual ~CacheEntry();
+
+  // CacheFileListener
+  NS_IMETHOD OnFileReady(nsresult aResult, bool aIsNew) override;
+  NS_IMETHOD OnFileDoomed(nsresult aResult) override;
+
+  // Keep the service alive during life-time of an entry
+  RefPtr<CacheStorageService> mService;
+
+  // We must monitor when a cache entry whose consumer is responsible
+  // for writing it the first time gets released.  We must then invoke
+  // waiting callbacks to not break the chain.
+  class Callback
+  {
+  public:
+    Callback(CacheEntry* aEntry,
+             nsICacheEntryOpenCallback *aCallback,
+             bool aReadOnly, bool aCheckOnAnyThread, bool aSecret);
+    // Special constructor for Callback objects added to the chain
+    // just to ensure proper defer dooming (recreation) of this entry.
+    Callback(CacheEntry* aEntry, bool aDoomWhenFoundInPinStatus);
+    Callback(Callback const &aThat);
+    ~Callback();
+
+    // Called when this callback record changes it's owning entry,
+    // mainly during recreation.
+    void ExchangeEntry(CacheEntry* aEntry);
+
+    // Returns true when an entry is about to be "defer" doomed and this is
+    // a "defer" callback.
+    bool DeferDoom(bool *aDoom) const;
+
+    // We are raising reference count here to take into account the pending
+    // callback (that virtually holds a ref to this entry before it gets
+    // it's pointer).
+    RefPtr<CacheEntry> mEntry;
+    nsCOMPtr<nsICacheEntryOpenCallback> mCallback;
+    nsCOMPtr<nsIThread> mTargetThread;
+    bool mReadOnly : 1;
+    bool mRevalidating : 1;
+    bool mCheckOnAnyThread : 1;
+    bool mRecheckAfterWrite : 1;
+    bool mNotWanted : 1;
+    bool mSecret : 1;
+
+    // These are set only for the defer-doomer Callback instance inserted
+    // to the callback chain.  When any of these is set and also any of
+    // the corressponding flags on the entry is set, this callback will
+    // indicate (via DeferDoom()) the entry have to be recreated/doomed.
+    bool mDoomWhenFoundPinned : 1;
+    bool mDoomWhenFoundNonPinned : 1;
+
+    nsresult OnCheckThread(bool *aOnCheckThread) const;
+    nsresult OnAvailThread(bool *aOnAvailThread) const;
+  };
+
+  // Since OnCacheEntryAvailable must be invoked on the main thread
+  // we need a runnable for it...
+  class AvailableCallbackRunnable : public Runnable
+  {
+  public:
+    AvailableCallbackRunnable(CacheEntry* aEntry,
+                              Callback const &aCallback)
+      : mEntry(aEntry)
+      , mCallback(aCallback)
+    {}
+
+  private:
+    NS_IMETHOD Run() override
+    {
+      mEntry->InvokeAvailableCallback(mCallback);
+      return NS_OK;
+    }
+
+    RefPtr<CacheEntry> mEntry;
+    Callback mCallback;
+  };
+
+  // Since OnCacheEntryDoomed must be invoked on the main thread
+  // we need a runnable for it...
+  class DoomCallbackRunnable : public Runnable
+  {
+  public:
+    DoomCallbackRunnable(CacheEntry* aEntry, nsresult aRv)
+      : mEntry(aEntry), mRv(aRv) {}
+
+  private:
+    NS_IMETHOD Run() override
+    {
+      nsCOMPtr<nsICacheEntryDoomCallback> callback;
+      {
+        mozilla::MutexAutoLock lock(mEntry->mLock);
+        mEntry->mDoomCallback.swap(callback);
+      }
+
+      if (callback)
+        callback->OnCacheEntryDoomed(mRv);
+      return NS_OK;
+    }
+
+    RefPtr<CacheEntry> mEntry;
+    nsresult mRv;
+  };
+
+  // Starts the load or just invokes the callback, bypasses (when required)
+  // if busy.  Returns true on job done, false on bypass.
+  bool Open(Callback & aCallback, bool aTruncate, bool aPriority, bool aBypassIfBusy);
+  // Loads from disk asynchronously
+  bool Load(bool aTruncate, bool aPriority);
+
+  void RememberCallback(Callback & aCallback);
+  void InvokeCallbacksLock();
+  void InvokeCallbacks();
+  bool InvokeCallbacks(bool aReadOnly);
+  bool InvokeCallback(Callback & aCallback);
+  void InvokeAvailableCallback(Callback const & aCallback);
+  void OnFetched(Callback const & aCallback);
+
+  nsresult OpenOutputStreamInternal(int64_t offset, nsIOutputStream * *_retval);
+  nsresult OpenInputStreamInternal(int64_t offset, const char *aAltDataType, nsIInputStream * *_retval);
+
+  void OnHandleClosed(CacheEntryHandle const* aHandle);
+
+private:
+  friend class CacheEntryHandle;
+  // Increment/decrements the number of handles keeping this entry.
+  void AddHandleRef() { ++mHandlesCount; }
+  void ReleaseHandleRef() { --mHandlesCount; }
+  // Current number of handles keeping this entry.
+  uint32_t HandlesCount() const { return mHandlesCount; }
+
+private:
+  friend class CacheOutputCloseListener;
+  void OnOutputClosed();
+
+private:
+  // Schedules a background operation on the management thread.
+  // When executed on the management thread directly, the operation(s)
+  // is (are) executed immediately.
+  void BackgroundOp(uint32_t aOperation, bool aForceAsync = false);
+  void StoreFrecency(double aFrecency);
+
+  // Called only from DoomAlreadyRemoved()
+  void DoomFile();
+  // When this entry is doomed the first time, this method removes
+  // any force-valid timing info for this entry.
+  void RemoveForcedValidity();
+
+  already_AddRefed<CacheEntryHandle> ReopenTruncated(bool aMemoryOnly,
+                                                     nsICacheEntryOpenCallback* aCallback);
+  void TransferCallbacks(CacheEntry & aFromEntry);
+
+  mozilla::Mutex mLock;
+
+  // Reflects the number of existing handles for this entry
+  ::mozilla::ThreadSafeAutoRefCnt mHandlesCount;
+
+  nsTArray<Callback> mCallbacks;
+  nsCOMPtr<nsICacheEntryDoomCallback> mDoomCallback;
+
+  RefPtr<CacheFile> mFile;
+
+  // Using ReleaseAcquire since we only control access to mFile with this.
+  // When mFileStatus is read and found success it is ensured there is mFile and
+  // that it is after a successful call to Init().
+  ::mozilla::Atomic<nsresult, ::mozilla::ReleaseAcquire> mFileStatus;
+  nsCString mURI;
+  nsCString mEnhanceID;
+  nsCString mStorageID;
+
+  // mUseDisk, mSkipSizeCheck, mIsDoomed are plain "bool", not "bool:1",
+  // so as to avoid bitfield races with the byte containing
+  // mSecurityInfoLoaded et al.  See bug 1278524.
+  //
+  // Whether it's allowed to persist the data to disk
+  bool const mUseDisk;
+  // Whether it should skip max size check.
+  bool const mSkipSizeCheck;
+  // Set when entry is doomed with AsyncDoom() or DoomAlreadyRemoved().
+  bool mIsDoomed;
+
+  // Following flags are all synchronized with the cache entry lock.
+
+  // Whether security info has already been looked up in metadata.
+  bool mSecurityInfoLoaded : 1;
+  // Prevents any callback invocation
+  bool mPreventCallbacks : 1;
+  // true: after load and an existing file, or after output stream has been opened.
+  //       note - when opening an input stream, and this flag is false, output stream
+  //       is open along ; this makes input streams on new entries behave correctly
+  //       when EOF is reached (WOULD_BLOCK is returned).
+  // false: after load and a new file, or dropped to back to false when a writer
+  //        fails to open an output stream.
+  bool mHasData : 1;
+  // The indication of pinning this entry was open with
+  bool mPinned : 1;
+  // Whether the pinning state of the entry is known (equals to the actual state
+  // of the cache file)
+  bool mPinningKnown : 1;
+
+  static char const * StateString(uint32_t aState);
+
+  enum EState {      // transiting to:
+    NOTLOADED = 0,   // -> LOADING | EMPTY
+    LOADING = 1,     // -> EMPTY | READY
+    EMPTY = 2,       // -> WRITING
+    WRITING = 3,     // -> EMPTY | READY
+    READY = 4,       // -> REVALIDATING
+    REVALIDATING = 5 // -> READY
+  };
+
+  // State of this entry.
+  EState mState;
+
+  enum ERegistration {
+    NEVERREGISTERED = 0, // The entry has never been registered
+    REGISTERED = 1,      // The entry is stored in the memory pool index
+    DEREGISTERED = 2     // The entry has been removed from the pool
+  };
+
+  // Accessed only on the management thread.  Records the state of registration
+  // this entry in the memory pool intermediate cache.
+  ERegistration mRegistration;
+
+  // If a new (empty) entry is requested to open an input stream before
+  // output stream has been opened, we must open output stream internally
+  // on CacheFile and hold until writer releases the entry or opens the output
+  // stream for read (then we trade him mOutputStream).
+  nsCOMPtr<nsIOutputStream> mOutputStream;
+
+  // Weak reference to the current writter.  There can be more then one
+  // writer at a time and OnHandleClosed() must be processed only for the
+  // current one.
+  CacheEntryHandle* mWriter;
+
+  // Background thread scheduled operation.  Set (under the lock) one
+  // of this flags to tell the background thread what to do.
+  class Ops {
+  public:
+    static uint32_t const REGISTER =          1 << 0;
+    static uint32_t const FRECENCYUPDATE =    1 << 1;
+    static uint32_t const CALLBACKS =         1 << 2;
+    static uint32_t const UNREGISTER =        1 << 3;
+
+    Ops() : mFlags(0) { }
+    uint32_t Grab() { uint32_t flags = mFlags; mFlags = 0; return flags; }
+    bool Set(uint32_t aFlags) { if (mFlags & aFlags) return false; mFlags |= aFlags; return true; }
+  private:
+    uint32_t mFlags;
+  } mBackgroundOperations;
+
+  nsCOMPtr<nsISupports> mSecurityInfo;
+  int64_t mPredictedDataSize;
+  mozilla::TimeStamp mLoadStart;
+  uint32_t mUseCount;
+};
+
+
+class CacheEntryHandle : public nsICacheEntry
+{
+public:
+  explicit CacheEntryHandle(CacheEntry* aEntry);
+  CacheEntry* Entry() const { return mEntry; }
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_FORWARD_NSICACHEENTRY(mEntry->)
+private:
+  virtual ~CacheEntryHandle();
+  RefPtr<CacheEntry> mEntry;
+};
+
+
+class CacheOutputCloseListener final : public Runnable
+{
+public:
+  void OnOutputClosed();
+
+private:
+  friend class CacheEntry;
+
+  virtual ~CacheOutputCloseListener();
+
+  NS_DECL_NSIRUNNABLE
+  explicit CacheOutputCloseListener(CacheEntry* aEntry);
+
+private:
+  RefPtr<CacheEntry> mEntry;
+};
+
+} // namespace net
+} // namespace mozilla
+
+#endif