/* 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 CacheFile__h__
#define CacheFile__h__

#include "CacheFileChunk.h"
#include "CacheFileIOManager.h"
#include "CacheFileMetadata.h"
#include "nsRefPtrHashtable.h"
#include "nsClassHashtable.h"
#include "nsICacheEntry.h"
#include "mozilla/Mutex.h"

class nsIInputStream;
class nsIOutputStream;
class nsICacheEntryMetaDataVisitor;

namespace mozilla {
namespace net {

class CacheFileInputStream;
class CacheFileOutputStream;
class CacheOutputCloseListener;
class MetadataWriteTimer;

#define CACHEFILELISTENER_IID \
{ /* 95e7f284-84ba-48f9-b1fc-3a7336b4c33c */       \
  0x95e7f284,                                      \
  0x84ba,                                          \
  0x48f9,                                          \
  {0xb1, 0xfc, 0x3a, 0x73, 0x36, 0xb4, 0xc3, 0x3c} \
}

class CacheFileListener : public nsISupports
{
public:
  NS_DECLARE_STATIC_IID_ACCESSOR(CACHEFILELISTENER_IID)

  NS_IMETHOD OnFileReady(nsresult aResult, bool aIsNew) = 0;
  NS_IMETHOD OnFileDoomed(nsresult aResult) = 0;
};

NS_DEFINE_STATIC_IID_ACCESSOR(CacheFileListener, CACHEFILELISTENER_IID)


class CacheFile final : public CacheFileChunkListener
                      , public CacheFileIOListener
                      , public CacheFileMetadataListener
{
public:
  NS_DECL_THREADSAFE_ISUPPORTS

  CacheFile();

  nsresult Init(const nsACString &aKey,
                bool aCreateNew,
                bool aMemoryOnly,
                bool aSkipSizeCheck,
                bool aPriority,
                bool aPinned,
                CacheFileListener *aCallback);

  NS_IMETHOD OnChunkRead(nsresult aResult, CacheFileChunk *aChunk) override;
  NS_IMETHOD OnChunkWritten(nsresult aResult, CacheFileChunk *aChunk) override;
  NS_IMETHOD OnChunkAvailable(nsresult aResult, uint32_t aChunkIdx,
                              CacheFileChunk *aChunk) override;
  NS_IMETHOD OnChunkUpdated(CacheFileChunk *aChunk) override;

  NS_IMETHOD OnFileOpened(CacheFileHandle *aHandle, nsresult aResult) override;
  NS_IMETHOD OnDataWritten(CacheFileHandle *aHandle, const char *aBuf,
                           nsresult aResult) override;
  NS_IMETHOD OnDataRead(CacheFileHandle *aHandle, char *aBuf, nsresult aResult) override;
  NS_IMETHOD OnFileDoomed(CacheFileHandle *aHandle, nsresult aResult) override;
  NS_IMETHOD OnEOFSet(CacheFileHandle *aHandle, nsresult aResult) override;
  NS_IMETHOD OnFileRenamed(CacheFileHandle *aHandle, nsresult aResult) override;
  virtual bool IsKilled() override;

  NS_IMETHOD OnMetadataRead(nsresult aResult) override;
  NS_IMETHOD OnMetadataWritten(nsresult aResult) override;

  NS_IMETHOD OpenInputStream(nsICacheEntry *aCacheEntryHandle, nsIInputStream **_retval);
  NS_IMETHOD OpenAlternativeInputStream(nsICacheEntry *aCacheEntryHandle,
                                        const char *aAltDataType, nsIInputStream **_retval);
  NS_IMETHOD OpenOutputStream(CacheOutputCloseListener *aCloseListener, nsIOutputStream **_retval);
  NS_IMETHOD OpenAlternativeOutputStream(CacheOutputCloseListener *aCloseListener,
                                         const char *aAltDataType, nsIOutputStream **_retval);
  NS_IMETHOD SetMemoryOnly();
  NS_IMETHOD Doom(CacheFileListener *aCallback);

  void Kill() { mKill = true; }
  nsresult   ThrowMemoryCachedData();

  nsresult GetAltDataSize(int64_t *aSize);

  // metadata forwarders
  nsresult GetElement(const char *aKey, char **_retval);
  nsresult SetElement(const char *aKey, const char *aValue);
  nsresult VisitMetaData(nsICacheEntryMetaDataVisitor *aVisitor);
  nsresult ElementsSize(uint32_t *_retval);
  nsresult SetExpirationTime(uint32_t aExpirationTime);
  nsresult GetExpirationTime(uint32_t *_retval);
  nsresult SetFrecency(uint32_t aFrecency);
  nsresult GetFrecency(uint32_t *_retval);
  nsresult GetLastModified(uint32_t *_retval);
  nsresult GetLastFetched(uint32_t *_retval);
  nsresult GetFetchCount(uint32_t *_retval);
  nsresult GetDiskStorageSizeInKB(uint32_t *aDiskStorageSize);
  // Called by upper layers to indicated the entry has been fetched,
  // i.e. delivered to the consumer.
  nsresult OnFetched();

  bool DataSize(int64_t* aSize);
  void Key(nsACString& aKey) { aKey = mKey; }
  bool IsDoomed();
  bool IsPinned() const { return mPinned; }
  bool IsWriteInProgress();

  // Memory reporting
  size_t SizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
  size_t SizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const;

private:
  friend class CacheFileIOManager;
  friend class CacheFileChunk;
  friend class CacheFileInputStream;
  friend class CacheFileOutputStream;
  friend class CacheFileAutoLock;
  friend class MetadataWriteTimer;

  virtual ~CacheFile();

  void     Lock();
  void     Unlock();
  void     AssertOwnsLock() const;
  void     ReleaseOutsideLock(RefPtr<nsISupports> aObject);

  enum ECallerType {
    READER    = 0,
    WRITER    = 1,
    PRELOADER = 2
  };

  nsresult DoomLocked(CacheFileListener *aCallback);

  nsresult GetChunkLocked(uint32_t aIndex, ECallerType aCaller,
                          CacheFileChunkListener *aCallback,
                          CacheFileChunk **_retval);

  void     PreloadChunks(uint32_t aIndex);
  bool     ShouldCacheChunk(uint32_t aIndex);
  bool     MustKeepCachedChunk(uint32_t aIndex);

  nsresult DeactivateChunk(CacheFileChunk *aChunk);
  void     RemoveChunkInternal(CacheFileChunk *aChunk, bool aCacheChunk);

  bool     OutputStreamExists(bool aAlternativeData);
  // Returns number of bytes that are available and can be read by input stream
  // without waiting for the data. The amount is counted from the start of
  // aIndex chunk and it is guaranteed that this data won't be released by
  // CleanUpCachedChunks().
  int64_t  BytesFromChunk(uint32_t aIndex, bool aAlternativeData);
  nsresult Truncate(int64_t aOffset);

  nsresult RemoveInput(CacheFileInputStream *aInput, nsresult aStatus);
  nsresult RemoveOutput(CacheFileOutputStream *aOutput, nsresult aStatus);
  nsresult NotifyChunkListener(CacheFileChunkListener *aCallback,
                               nsIEventTarget *aTarget,
                               nsresult aResult,
                               uint32_t aChunkIdx,
                               CacheFileChunk *aChunk);
  nsresult QueueChunkListener(uint32_t aIndex,
                              CacheFileChunkListener *aCallback);
  nsresult NotifyChunkListeners(uint32_t aIndex, nsresult aResult,
                                CacheFileChunk *aChunk);
  bool     HaveChunkListeners(uint32_t aIndex);
  void     NotifyListenersAboutOutputRemoval();

  bool IsDirty();
  void WriteMetadataIfNeeded();
  void WriteMetadataIfNeededLocked(bool aFireAndForget = false);
  void PostWriteTimer();

  void CleanUpCachedChunks();

  nsresult PadChunkWithZeroes(uint32_t aChunkIdx);

  void SetError(nsresult aStatus);

  nsresult InitIndexEntry();

  mozilla::Mutex mLock;
  bool           mOpeningFile;
  bool           mReady;
  bool           mMemoryOnly;
  bool           mSkipSizeCheck;
  bool           mOpenAsMemoryOnly;
  bool           mPinned;
  bool           mPriority;
  bool           mDataAccessed;
  bool           mDataIsDirty;
  bool           mWritingMetadata;
  bool           mPreloadWithoutInputStreams;
  uint32_t       mPreloadChunkCount;
  nsresult       mStatus;
  int64_t        mDataSize; // Size of the whole data including eventual
                            // alternative data represenation.
  int64_t        mAltDataOffset; // If there is alternative data present, it
                                 // contains size of the original data, i.e.
                                 // offset where alternative data starts.
                                 // Otherwise it is -1.
  nsCString      mKey;

  RefPtr<CacheFileHandle>      mHandle;
  RefPtr<CacheFileMetadata>    mMetadata;
  nsCOMPtr<CacheFileListener>  mListener;
  nsCOMPtr<CacheFileIOListener>   mDoomAfterOpenListener;
  Atomic<bool, Relaxed>        mKill;

  nsRefPtrHashtable<nsUint32HashKey, CacheFileChunk> mChunks;
  nsClassHashtable<nsUint32HashKey, ChunkListeners> mChunkListeners;
  nsRefPtrHashtable<nsUint32HashKey, CacheFileChunk> mCachedChunks;
  // We can truncate data only if there is no input/output stream beyond the
  // truncate position, so only unused chunks can be thrown away. But it can
  // happen that we need to throw away a chunk that is still in mChunks (i.e.
  // an active chunk) because deactivation happens with a small delay. We cannot
  // delete such chunk immediately but we need to ensure that such chunk won't
  // be returned by GetChunkLocked, so we move this chunk into mDiscardedChunks
  // and mark it as discarded.
  nsTArray<RefPtr<CacheFileChunk> > mDiscardedChunks;

  nsTArray<CacheFileInputStream*> mInputs;
  CacheFileOutputStream          *mOutput;

  nsTArray<RefPtr<nsISupports>> mObjsToRelease;
};

class CacheFileAutoLock {
public:
  explicit CacheFileAutoLock(CacheFile *aFile)
    : mFile(aFile)
    , mLocked(true)
  {
    mFile->Lock();
  }
  ~CacheFileAutoLock()
  {
    if (mLocked)
      mFile->Unlock();
  }
  void Lock()
  {
    MOZ_ASSERT(!mLocked);
    mFile->Lock();
    mLocked = true;
  }
  void Unlock()
  {
    MOZ_ASSERT(mLocked);
    mFile->Unlock();
    mLocked = false;
  }

private:
  RefPtr<CacheFile> mFile;
  bool mLocked;
};

} // namespace net
} // namespace mozilla

#endif