/* -*- Mode: C++; tab-width: 2; 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 mozilla_net_Http2Compression_Internal_h

#define mozilla_net_Http2Compression_Internal_h

// HPACK - RFC 7541

// https://www.rfc-editor.org/rfc/rfc7541.txt

#include "mozilla/Attributes.h"

#include "nsDeque.h"

#include "nsString.h"

#include "nsIMemoryReporter.h"

#include "mozilla/Telemetry.h"

namespace mozilla {

namespace net {

struct HuffmanIncomingTable;

void Http2CompressionCleanup();

class nvPair

{

public:

nvPair(const nsACString &name, const nsACString &value)

  : mName(name)

  , mValue(value)

  { }

  uint32_t Size() const { return mName.Length() + mValue.Length() + 32; }

  size_t SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const;

  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const;

  nsCString mName;

  nsCString mValue;

};

class nvFIFO

{

public:

  nvFIFO();

  ~nvFIFO();

  void AddElement(const nsCString &name, const nsCString &value);

  void AddElement(const nsCString &name);

  void RemoveElement();

  uint32_t ByteCount() const;

  uint32_t Length() const;

  uint32_t VariableLength() const;

  size_t StaticLength() const;

  void Clear();

  const nvPair *operator[] (size_t index) const;

private:

  uint32_t mByteCount;

  nsDeque  mTable;

};

class HpackDynamicTableReporter;

class Http2BaseCompressor

{

public:

  Http2BaseCompressor();

  virtual ~Http2BaseCompressor();

  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;

  nsresult SetInitialMaxBufferSize(uint32_t maxBufferSize);

protected:

  const static uint32_t kDefaultMaxBuffer = 4096;

  virtual void ClearHeaderTable();

  virtual void MakeRoom(uint32_t amount, const char *direction);

  virtual void DumpState();

  virtual void SetMaxBufferSizeInternal(uint32_t maxBufferSize);

  nsACString *mOutput;

  nvFIFO mHeaderTable;

  uint32_t mMaxBuffer;

  uint32_t mMaxBufferSetting;

  bool mSetInitialMaxBufferSizeAllowed;

  uint32_t mPeakSize;

  uint32_t mPeakCount;

  MOZ_INIT_OUTSIDE_CTOR

  Telemetry::HistogramID mPeakSizeID;

  MOZ_INIT_OUTSIDE_CTOR

  Telemetry::HistogramID mPeakCountID;

private:

  RefPtr<HpackDynamicTableReporter> mDynamicReporter;

};

class Http2Compressor;

class Http2Decompressor final : public Http2BaseCompressor

{

public:

  Http2Decompressor()

    : mOffset(0)

    , mData(nullptr)

    , mDataLen(0)

    , mSeenNonColonHeader(false)

    , mIsPush(false)

  {

    mPeakSizeID = Telemetry::HPACK_PEAK_SIZE_DECOMPRESSOR;

    mPeakCountID = Telemetry::HPACK_PEAK_COUNT_DECOMPRESSOR;

  };

  virtual ~Http2Decompressor() = default;

  // NS_OK: Produces the working set of HTTP/1 formatted headers

  MOZ_MUST_USE nsresult DecodeHeaderBlock(const uint8_t *data,

                                          uint32_t datalen, nsACString &output,

                                          bool isPush);

  void GetStatus(nsACString &hdr) { hdr = mHeaderStatus; }

  void GetHost(nsACString &hdr) { hdr = mHeaderHost; }

  void GetScheme(nsACString &hdr) { hdr = mHeaderScheme; }

  void GetPath(nsACString &hdr) { hdr = mHeaderPath; }

  void GetMethod(nsACString &hdr) { hdr = mHeaderMethod; }

private:

  MOZ_MUST_USE nsresult DoIndexed();

  MOZ_MUST_USE nsresult DoLiteralWithoutIndex();

  MOZ_MUST_USE nsresult DoLiteralWithIncremental();

  MOZ_MUST_USE nsresult DoLiteralInternal(nsACString &, nsACString &, uint32_t);

  MOZ_MUST_USE nsresult DoLiteralNeverIndexed();

  MOZ_MUST_USE nsresult DoContextUpdate();

  MOZ_MUST_USE nsresult DecodeInteger(uint32_t prefixLen, uint32_t &result);

  MOZ_MUST_USE nsresult OutputHeader(uint32_t index);

  MOZ_MUST_USE nsresult OutputHeader(const nsACString &name, const nsACString &value);

  MOZ_MUST_USE nsresult CopyHeaderString(uint32_t index, nsACString &name);

  MOZ_MUST_USE nsresult CopyStringFromInput(uint32_t index, nsACString &val);

  uint8_t ExtractByte(uint8_t bitsLeft, uint32_t &bytesConsumed);

  MOZ_MUST_USE nsresult CopyHuffmanStringFromInput(uint32_t index, nsACString &val);

  MOZ_MUST_USE nsresult

  DecodeHuffmanCharacter(const HuffmanIncomingTable *table, uint8_t &c,

                         uint32_t &bytesConsumed, uint8_t &bitsLeft);

  MOZ_MUST_USE nsresult

  DecodeFinalHuffmanCharacter(const HuffmanIncomingTable *table, uint8_t &c,

                              uint8_t &bitsLeft);

  nsCString mHeaderStatus;

  nsCString mHeaderHost;

  nsCString mHeaderScheme;

  nsCString mHeaderPath;

  nsCString mHeaderMethod;

  // state variables when DecodeBlock() is on the stack

  uint32_t mOffset;

  const uint8_t *mData;

  uint32_t mDataLen;

  bool mSeenNonColonHeader;

  bool mIsPush;

};

class Http2Compressor final : public Http2BaseCompressor

{

public:

  Http2Compressor() : mParsedContentLength(-1),

                      mBufferSizeChangeWaiting(false),

                      mLowestBufferSizeWaiting(0)

  {

    mPeakSizeID = Telemetry::HPACK_PEAK_SIZE_COMPRESSOR;

    mPeakCountID = Telemetry::HPACK_PEAK_COUNT_COMPRESSOR;

  };

  virtual ~Http2Compressor() = default;

  // HTTP/1 formatted header block as input - HTTP/2 formatted

  // header block as output

  MOZ_MUST_USE nsresult EncodeHeaderBlock(const nsCString &nvInput,

                                          const nsACString &method,

                                          const nsACString &path,

                                          const nsACString &host,

                                          const nsACString &scheme,

                                          bool connectForm,

                                          nsACString &output);

  int64_t GetParsedContentLength() { return mParsedContentLength; } // -1 on not found

  void SetMaxBufferSize(uint32_t maxBufferSize);

private:

  enum outputCode {

    kNeverIndexedLiteral,

    kPlainLiteral,

    kIndexedLiteral,

    kIndex

  };

  void DoOutput(Http2Compressor::outputCode code,

                const class nvPair *pair, uint32_t index);

  void EncodeInteger(uint32_t prefixLen, uint32_t val);

  void ProcessHeader(const nvPair inputPair, bool noLocalIndex,

                     bool neverIndex);

  void HuffmanAppend(const nsCString &value);

  void EncodeTableSizeChange(uint32_t newMaxSize);

  int64_t mParsedContentLength;

  bool mBufferSizeChangeWaiting;

  uint32_t mLowestBufferSizeWaiting;

};

} // namespace net

} // namespace mozilla

#endif // mozilla_net_Http2Compression_Internal_h