/* -*- 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 nsUnknownDecoder_h__

#define nsUnknownDecoder_h__

#include "nsIStreamConverter.h"

#include "nsIThreadRetargetableStreamListener.h"

#include "nsIContentSniffer.h"

#include "mozilla/Mutex.h"

#include "mozilla/Atomics.h"

#include "nsCOMPtr.h"

#include "nsString.h"

#define NS_UNKNOWNDECODER_CID                        \

{ /* 7d7008a0-c49a-11d3-9b22-0080c7cb1080 */         \

    0x7d7008a0,                                      \

    0xc49a,                                          \

    0x11d3,                                          \

    {0x9b, 0x22, 0x00, 0x80, 0xc7, 0xcb, 0x10, 0x80}       \

}

class nsUnknownDecoder : public nsIStreamConverter

                       , public nsIContentSniffer

                       , public nsIThreadRetargetableStreamListener

{

public:

  // nsISupports methods

  NS_DECL_ISUPPORTS

  // nsIStreamConverter methods

  NS_DECL_NSISTREAMCONVERTER

  // nsIStreamListener methods

  NS_DECL_NSISTREAMLISTENER

  // nsIRequestObserver methods

  NS_DECL_NSIREQUESTOBSERVER

  // nsIContentSniffer methods

  NS_DECL_NSICONTENTSNIFFER

  // nsIThreadRetargetableStreamListener methods

  NS_DECL_NSITHREADRETARGETABLESTREAMLISTENER

  nsUnknownDecoder();

protected:

  virtual ~nsUnknownDecoder();

  virtual void DetermineContentType(nsIRequest* aRequest);

  nsresult FireListenerNotifications(nsIRequest* request, nsISupports *aCtxt);

  class ConvertedStreamListener: public nsIStreamListener

  {

  public:

    explicit ConvertedStreamListener(nsUnknownDecoder *aDecoder);

    NS_DECL_ISUPPORTS

    NS_DECL_NSIREQUESTOBSERVER

    NS_DECL_NSISTREAMLISTENER

  private:

    virtual ~ConvertedStreamListener() = default;

    static nsresult AppendDataToString(nsIInputStream* inputStream,

                                       void* closure,

                                       const char* rawSegment,

                                       uint32_t toOffset,

                                       uint32_t count,

                                       uint32_t* writeCount);

    nsUnknownDecoder *mDecoder;

  };

protected:

  nsCOMPtr<nsIStreamListener> mNextListener;

  // Function to use to check whether sniffing some potentially

  // dangerous types (eg HTML) is ok for this request.  We can disable

  // sniffing for local files if needed using this.  Just a security

  // precation thingy... who knows when we suddenly need to flip this

  // pref?

  bool AllowSniffing(nsIRequest* aRequest);

  // Various sniffer functions.  Returning true means that a type

  // was determined; false means no luck.

  bool SniffForHTML(nsIRequest* aRequest);

  bool SniffForXML(nsIRequest* aRequest);

  // SniffURI guesses at the content type based on the URI (typically

  // using the extentsion)

  bool SniffURI(nsIRequest* aRequest);

  // LastDitchSniff guesses at text/plain vs. application/octet-stream

  // by just looking at whether the data contains null bytes, and

  // maybe at the fraction of chars with high bit set.  Use this only

  // as a last-ditch attempt to decide a content type!

  bool LastDitchSniff(nsIRequest* aRequest);

  /**

   * An entry struct for our array of sniffers.  Each entry has either

   * a type associated with it (set these with the SNIFFER_ENTRY macro)

   * or a function to be executed (set these with the

   * SNIFFER_ENTRY_WITH_FUNC macro).  The function should take a single

   * nsIRequest* and returns bool -- true if it sets mContentType,

   * false otherwise

   */

  struct nsSnifferEntry {

    typedef bool (nsUnknownDecoder::*TypeSniffFunc)(nsIRequest* aRequest);

    const char* mBytes;

    uint32_t mByteLen;

    // Exactly one of mMimeType and mContentTypeSniffer should be set non-null

    const char* mMimeType;

    TypeSniffFunc mContentTypeSniffer;

  };

#define SNIFFER_ENTRY(_bytes, _type) \

  { _bytes, sizeof(_bytes) - 1, _type, nullptr }

#define SNIFFER_ENTRY_WITH_FUNC(_bytes, _func) \

  { _bytes, sizeof(_bytes) - 1, nullptr, _func }

  static nsSnifferEntry sSnifferEntries[];

  static uint32_t sSnifferEntryNum;

  // We guarantee in order delivery of OnStart, OnStop and OnData, therefore

  // we do not need proper locking for mBuffer.

  mozilla::Atomic<char *>mBuffer;

  mozilla::Atomic<uint32_t> mBufferLen;

  mozilla::Atomic<bool> mRequireHTMLsuffix;

  nsCString mContentType;

  // This mutex syncs: mContentType, mDecodedData and mNextListener.

  mutable mozilla::Mutex mMutex;

protected:

  nsresult ConvertEncodedData(nsIRequest* request, const char* data,

                              uint32_t length);

  nsCString mDecodedData; // If data are encoded this will be uncompress data.

};

#define NS_BINARYDETECTOR_CID                        \

{ /* a2027ec6-ba0d-4c72-805d-148233f5f33c */         \

    0xa2027ec6,                                      \

    0xba0d,                                          \

    0x4c72,                                          \

    {0x80, 0x5d, 0x14, 0x82, 0x33, 0xf5, 0xf3, 0x3c} \

}

/**

 * Class that detects whether a data stream is text or binary.  This reuses

 * most of nsUnknownDecoder except the actual content-type determination logic

 * -- our overridden DetermineContentType simply calls LastDitchSniff and sets

 * the type to APPLICATION_GUESS_FROM_EXT if the data is detected as binary.

 */

class nsBinaryDetector : public nsUnknownDecoder

{

protected:

  virtual void DetermineContentType(nsIRequest* aRequest) override;

};

#define NS_BINARYDETECTOR_CATEGORYENTRY \

  { NS_CONTENT_SNIFFER_CATEGORY, "Binary Detector", NS_BINARYDETECTOR_CONTRACTID }

#endif /* nsUnknownDecoder_h__ */