/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Henri Sivonen <hsivonen@iki.fi>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef nsHtml5StreamParser_h__
#define nsHtml5StreamParser_h__

#include "nsAutoPtr.h"
#include "nsCOMPtr.h"
#include "nsIStreamListener.h"
#include "nsICharsetDetectionObserver.h"
#include "nsHtml5MetaScanner.h"
#include "nsIUnicodeDecoder.h"
#include "nsHtml5TreeOpExecutor.h"
#include "nsHtml5UTF16Buffer.h"
#include "nsIInputStream.h"
#include "nsICharsetAlias.h"

class nsHtml5Parser;

#define NS_HTML5_STREAM_PARSER_READ_BUFFER_SIZE 1024
#define NS_HTML5_STREAM_PARSER_SNIFFING_BUFFER_SIZE 512

enum eBomState {
  /**
   * BOM sniffing hasn't started.
   */
  BOM_SNIFFING_NOT_STARTED = 0,

  /**
   * BOM sniffing is ongoing, and the first byte of an UTF-16LE BOM has been
   * seen.
   */
  SEEN_UTF_16_LE_FIRST_BYTE = 1,

  /**
   * BOM sniffing is ongoing, and the first byte of an UTF-16BE BOM has been
   * seen.
   */
  SEEN_UTF_16_BE_FIRST_BYTE = 2,

  /**
   * BOM sniffing is ongoing, and the first byte of an UTF-8 BOM has been
   * seen.
   */
  SEEN_UTF_8_FIRST_BYTE = 3,

  /**
   * BOM sniffing is ongoing, and the first and second bytes of an UTF-8 BOM
   * have been seen.
   */
  SEEN_UTF_8_SECOND_BYTE = 4,

  /**
   * BOM sniffing was started but is now over for whatever reason.
   */
  BOM_SNIFFING_OVER = 5
};

class nsHtml5StreamParser : public nsIStreamListener,
                            public nsICharsetDetectionObserver {
  public:
    NS_DECL_AND_IMPL_ZEROING_OPERATOR_NEW
    NS_DECL_CYCLE_COLLECTING_ISUPPORTS
    NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsHtml5StreamParser, nsIStreamListener)

    nsHtml5StreamParser(nsHtml5Tokenizer* aTokenizer,
                        nsHtml5TreeOpExecutor* aExecutor,
                        nsHtml5Parser* aOwner);
                        
    virtual ~nsHtml5StreamParser();

    // nsIRequestObserver methods:
    NS_DECL_NSIREQUESTOBSERVER
    // nsIStreamListener methods:
    NS_DECL_NSISTREAMLISTENER
    
    // nsICharsetDetectionObserver
    /**
     * Chardet calls this to report the detection result
     */
    NS_IMETHOD Notify(const char* aCharset, nsDetectionConfident aConf);

    // EncodingDeclarationHandler
    /**
     * Tree builder uses this to report a late <meta charset>
     */
    void internalEncodingDeclaration(nsString* aEncoding);

    // Not from an external interface

    /**
     *  Call this method once you've created a parser, and want to instruct it
     *  about what charset to load
     *
     *  @param   aCharset the charset of a document
     *  @param   aCharsetSource the source of the charset
     */
    inline void SetDocumentCharset(const nsACString& aCharset, PRInt32 aSource) {
      mCharset = aCharset;
      mCharsetSource = aSource;
    }
    
    inline void SetObserver(nsIRequestObserver* aObserver) {
      mObserver = aObserver;
    }
    
    nsresult GetChannel(nsIChannel** aChannel);

    inline void Block() {
      mBlocked = PR_TRUE;
    }
    
    inline void Unblock() {
      mBlocked = PR_FALSE;
    }

    inline void Suspend() {
      mSuspending = PR_TRUE;
    }

    void ParseUntilSuspend();
    
    PRBool IsDone() {
      return mDone;
    }
    
  private:

    static NS_METHOD ParserWriteFunc(nsIInputStream* aInStream,
                                     void* aHtml5StreamParser,
                                     const char* aFromSegment,
                                     PRUint32 aToOffset,
                                     PRUint32 aCount,
                                     PRUint32* aWriteCount);

    /**
     * True when there is a Unicode decoder already
     */
    inline PRBool HasDecoder() {
      return !!mUnicodeDecoder;
    }

    /**
     * Push bytes from network when there is no Unicode decoder yet
     */
    nsresult SniffStreamBytes(const PRUint8* aFromSegment,
                              PRUint32 aCount,
                              PRUint32* aWriteCount);

    /**
     * Push bytes from network when there is a Unicode decoder already
     */
    nsresult WriteStreamBytes(const PRUint8* aFromSegment,
                              PRUint32 aCount,
                              PRUint32* aWriteCount);
    
    /**
     * <meta charset> scan failed. Try chardet if applicable. After this, the
     * the parser will have some encoding even if a last resolt fallback.
     *
     * @param aFromSegment The current network buffer or null if the sniffing
     *                     buffer is being flushed due to network stream ending.
     * @param aCount       The number of bytes in aFromSegment (ignored if
     *                     aFromSegment is null)
     * @param aWriteCount  Return value for how many bytes got read from the
     *                     buffer.
     * @param aCountToSniffingLimit The number of unfilled slots in
     *                              mSniffingBuffer
     */
    nsresult FinalizeSniffing(const PRUint8* aFromSegment,
                              PRUint32 aCount,
                              PRUint32* aWriteCount,
                              PRUint32 aCountToSniffingLimit);

    /**
     * Set up the Unicode decoder and write the sniffing buffer into it
     * followed by the current network buffer.
     *
     * @param aFromSegment The current network buffer or null if the sniffing
     *                     buffer is being flushed due to network stream ending.
     * @param aCount       The number of bytes in aFromSegment (ignored if
     *                     aFromSegment is null)
     * @param aWriteCount  Return value for how many bytes got read from the
     *                     buffer.
     */
    nsresult SetupDecodingAndWriteSniffingBufferAndCurrentSegment(const PRUint8* aFromSegment,
                                                                  PRUint32 aCount,
                                                                  PRUint32* aWriteCount);

    /**
     * Write the sniffing buffer into the Unicode decoder followed by the
     * current network buffer.
     *
     * @param aFromSegment The current network buffer or null if the sniffing
     *                     buffer is being flushed due to network stream ending.
     * @param aCount       The number of bytes in aFromSegment (ignored if
     *                     aFromSegment is null)
     * @param aWriteCount  Return value for how many bytes got read from the
     *                     buffer.
     */
    nsresult WriteSniffingBufferAndCurrentSegment(const PRUint8* aFromSegment,
                                                  PRUint32 aCount,
                                                  PRUint32* aWriteCount);

    /**
     * Initialize the Unicode decoder, mark the BOM as the source and
     * drop the sniffer.
     *
     * @param aCharsetName The charset name to report to the outside (UTF-16
     *                     or UTF-8)
     * @param aDecoderCharsetName The actual name for the decoder's charset
     *                            (UTF-16BE, UTF-16LE or UTF-8; the BOM has
     *                            been swallowed)
     */
    nsresult SetupDecodingFromBom(const char* aCharsetName,
                                  const char* aDecoderCharsetName);

    nsCOMPtr<nsIRequest>          mRequest;
    nsCOMPtr<nsIRequestObserver>  mObserver;

    /**
     * The Unicode decoder
     */
    nsCOMPtr<nsIUnicodeDecoder>   mUnicodeDecoder;

    /**
     * The buffer for sniffing the character encoding
     */
    nsAutoArrayPtr<PRUint8>       mSniffingBuffer;

    /**
     * The number of meaningful bytes in mSniffingBuffer
     */
    PRUint32                      mSniffingLength;

    /**
     * BOM sniffing state
     */
    eBomState                     mBomState;

    /**
     * <meta> prescan implementation
     */
    nsAutoPtr<nsHtml5MetaScanner> mMetaScanner;

    // encoding-related stuff
    /**
     * The source (confidence) of the character encoding in use
     */
    PRInt32                       mCharsetSource;

    /**
     * The character encoding in use
     */
    nsCString                     mCharset;

    // Portable parser objects
    /**
     * The first buffer in the pending UTF-16 buffer queue
     */
    nsHtml5UTF16Buffer*           mFirstBuffer; // manually managed strong ref

    /**
     * The last buffer in the pending UTF-16 buffer queue
     */
    nsHtml5UTF16Buffer*           mLastBuffer; // weak ref; always points to
                      // a buffer of the size NS_HTML5_STREAM_PARSER_READ_BUFFER_SIZE

    /**
     * The tree operation executor
     */
    nsHtml5TreeOpExecutor*        mExecutor;

    /**
     * The HTML5 tree builder
     */
    nsHtml5TreeBuilder*           mTreeBuilder;

    /**
     * The HTML5 tokenizer
     */
    nsHtml5Tokenizer*             mTokenizer;

    nsCOMPtr<nsHtml5Parser>       mOwner;

    /**
     * Whether the last character tokenized was a carriage return (for CRLF)
     */
    PRBool                        mLastWasCR;

    /**
     * The parser is blocking on a script
     */
    PRBool                        mBlocked;

    /**
     * The event loop will spin ASAP
     */
    PRBool                        mSuspending;

    /**
     * Whether the stream parser is done
     */
    PRBool                        mDone;

#ifdef DEBUG
    /**
     * For asserting stream life cycle
     */
    eStreamState                  mStreamListenerState;
#endif

};

#endif // nsHtml5StreamParser_h__