michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim:set ts=2 sw=2 sts=2 tw=80 et cindent: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "nsMediaSniffer.h"
michael@0: #include "nsIHttpChannel.h"
michael@0: #include "nsString.h"
michael@0: #include "nsMimeTypes.h"
michael@0: #include "mozilla/ArrayUtils.h"
michael@0: #include "mozilla/ModuleUtils.h"
michael@0: #include "mp3sniff.h"
michael@0: #ifdef MOZ_WEBM
michael@0: #include "nestegg/nestegg.h"
michael@0: #endif
michael@0: 
michael@0: #include "nsIClassInfoImpl.h"
michael@0: #include <algorithm>
michael@0: 
michael@0: // The minimum number of bytes that are needed to attempt to sniff an mp4 file.
michael@0: static const unsigned MP4_MIN_BYTES_COUNT = 12;
michael@0: // The maximum number of bytes to consider when attempting to sniff a file.
michael@0: static const uint32_t MAX_BYTES_SNIFFED = 512;
michael@0: // The maximum number of bytes to consider when attempting to sniff for a mp3
michael@0: // bitstream.
michael@0: // This is 320kbps * 144 / 32kHz + 1 padding byte + 4 bytes of capture pattern.
michael@0: static const uint32_t MAX_BYTES_SNIFFED_MP3 = 320 * 144 / 32 + 1 + 4;
michael@0: 
michael@0: NS_IMPL_ISUPPORTS(nsMediaSniffer, nsIContentSniffer)
michael@0: 
michael@0: nsMediaSniffer::nsMediaSnifferEntry nsMediaSniffer::sSnifferEntries[] = {
michael@0:   // The string OggS, followed by the null byte.
michael@0:   PATTERN_ENTRY("\xFF\xFF\xFF\xFF\xFF", "OggS", APPLICATION_OGG),
michael@0:   // The string RIFF, followed by four bytes, followed by the string WAVE
michael@0:   PATTERN_ENTRY("\xFF\xFF\xFF\xFF\x00\x00\x00\x00\xFF\xFF\xFF\xFF", "RIFF\x00\x00\x00\x00WAVE", AUDIO_WAV),
michael@0:   // mp3 with ID3 tags, the string "ID3".
michael@0:   PATTERN_ENTRY("\xFF\xFF\xFF", "ID3", AUDIO_MP3)
michael@0: };
michael@0: 
michael@0: // This function implements mp4 sniffing algorithm, described at
michael@0: // http://mimesniff.spec.whatwg.org/#signature-for-mp4
michael@0: static bool MatchesMP4(const uint8_t* aData, const uint32_t aLength)
michael@0: {
michael@0:   if (aLength <= MP4_MIN_BYTES_COUNT) {
michael@0:     return false;
michael@0:   }
michael@0:   // Conversion from big endian to host byte order.
michael@0:   uint32_t boxSize = (uint32_t)(aData[3] | aData[2] << 8 | aData[1] << 16 | aData[0] << 24);
michael@0: 
michael@0:   // Boxsize should be evenly divisible by 4.
michael@0:   if (boxSize % 4 || aLength < boxSize) {
michael@0:     return false;
michael@0:   }
michael@0:   // The string "ftyp".
michael@0:   if (aData[4] != 0x66 ||
michael@0:       aData[5] != 0x74 ||
michael@0:       aData[6] != 0x79 ||
michael@0:       aData[7] != 0x70) {
michael@0:     return false;
michael@0:   }
michael@0:   for (uint32_t i = 2; i <= boxSize / 4 - 1 ; i++) {
michael@0:     if (i == 3) {
michael@0:       continue;
michael@0:     }
michael@0:     // The string "mp42" or "mp41".
michael@0:     if (aData[4*i]   == 0x6D &&
michael@0:         aData[4*i+1] == 0x70 &&
michael@0:         aData[4*i+2] == 0x34) {
michael@0:       return true;
michael@0:     }
michael@0:     // The string "isom" or "iso2".
michael@0:     if (aData[4*i]   == 0x69 &&
michael@0:         aData[4*i+1] == 0x73 &&
michael@0:         aData[4*i+2] == 0x6F &&
michael@0:         (aData[4*i+3] == 0x6D || aData[4*i+3] == 0x32)) {
michael@0:       return true;
michael@0:     }
michael@0:   }
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: static bool MatchesWebM(const uint8_t* aData, const uint32_t aLength)
michael@0: {
michael@0: #ifdef MOZ_WEBM
michael@0:   return nestegg_sniff((uint8_t*)aData, aLength) ? true : false;
michael@0: #else
michael@0:   return false;
michael@0: #endif
michael@0: }
michael@0: 
michael@0: // This function implements mp3 sniffing based on parsing
michael@0: // packet headers and looking for expected boundaries.
michael@0: static bool MatchesMP3(const uint8_t* aData, const uint32_t aLength)
michael@0: {
michael@0:   return mp3_sniff(aData, (long)aLength);
michael@0: }
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsMediaSniffer::GetMIMETypeFromContent(nsIRequest* aRequest,
michael@0:                                        const uint8_t* aData,
michael@0:                                        const uint32_t aLength,
michael@0:                                        nsACString& aSniffedType)
michael@0: {
michael@0:   // For media, we want to sniff only if the Content-Type is unknown, or if it
michael@0:   // is application/octet-stream.
michael@0:   nsCOMPtr<nsIChannel> channel = do_QueryInterface(aRequest);
michael@0:   if (channel) {
michael@0:     nsAutoCString contentType;
michael@0:     nsresult rv = channel->GetContentType(contentType);
michael@0:     NS_ENSURE_SUCCESS(rv, rv);
michael@0:     if (!contentType.IsEmpty() &&
michael@0:         !contentType.EqualsLiteral(APPLICATION_OCTET_STREAM) &&
michael@0:         !contentType.EqualsLiteral(UNKNOWN_CONTENT_TYPE)) {
michael@0:       return NS_ERROR_NOT_AVAILABLE;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   const uint32_t clampedLength = std::min(aLength, MAX_BYTES_SNIFFED);
michael@0: 
michael@0:   for (uint32_t i = 0; i < mozilla::ArrayLength(sSnifferEntries); ++i) {
michael@0:     const nsMediaSnifferEntry& currentEntry = sSnifferEntries[i];
michael@0:     if (clampedLength < currentEntry.mLength || currentEntry.mLength == 0) {
michael@0:       continue;
michael@0:     }
michael@0:     bool matched = true;
michael@0:     for (uint32_t j = 0; j < currentEntry.mLength; ++j) {
michael@0:       if ((currentEntry.mMask[j] & aData[j]) != currentEntry.mPattern[j]) {
michael@0:         matched = false;
michael@0:         break;
michael@0:       }
michael@0:     }
michael@0:     if (matched) {
michael@0:       aSniffedType.AssignASCII(currentEntry.mContentType);
michael@0:       return NS_OK;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   if (MatchesMP4(aData, clampedLength)) {
michael@0:     aSniffedType.AssignLiteral(VIDEO_MP4);
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   if (MatchesWebM(aData, clampedLength)) {
michael@0:     aSniffedType.AssignLiteral(VIDEO_WEBM);
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   // Bug 950023: 512 bytes are often not enough to sniff for mp3.
michael@0:   if (MatchesMP3(aData, std::min(aLength, MAX_BYTES_SNIFFED_MP3))) {
michael@0:     aSniffedType.AssignLiteral(AUDIO_MP3);
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   // Could not sniff the media type, we are required to set it to
michael@0:   // application/octet-stream.
michael@0:   aSniffedType.AssignLiteral(APPLICATION_OCTET_STREAM);
michael@0:   return NS_ERROR_NOT_AVAILABLE;
michael@0: }