зеркало из https://github.com/mozilla/gecko-dev.git
201 строка
6.9 KiB
C++
201 строка
6.9 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim:set ts=2 sw=2 sts=2 tw=80 et cindent: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "nsMediaSniffer.h"
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#include "nsIHttpChannel.h"
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#include "nsString.h"
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#include "nsMimeTypes.h"
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#include "mozilla/ArrayUtils.h"
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#include "mozilla/ModuleUtils.h"
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#include "mp3sniff.h"
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#include "nestegg/nestegg.h"
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#include "FlacDemuxer.h"
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#include "nsIClassInfoImpl.h"
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#include <algorithm>
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// The minimum number of bytes that are needed to attempt to sniff an mp4 file.
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static const unsigned MP4_MIN_BYTES_COUNT = 12;
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// The maximum number of bytes to consider when attempting to sniff a file.
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static const uint32_t MAX_BYTES_SNIFFED = 512;
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// The maximum number of bytes to consider when attempting to sniff for a mp3
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// bitstream.
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// This is 320kbps * 144 / 32kHz + 1 padding byte + 4 bytes of capture pattern.
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static const uint32_t MAX_BYTES_SNIFFED_MP3 = 320 * 144 / 32 + 1 + 4;
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NS_IMPL_ISUPPORTS(nsMediaSniffer, nsIContentSniffer)
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nsMediaSnifferEntry nsMediaSniffer::sSnifferEntries[] = {
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// The string OggS, followed by the null byte.
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PATTERN_ENTRY("\xFF\xFF\xFF\xFF\xFF", "OggS", APPLICATION_OGG),
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// The string RIFF, followed by four bytes, followed by the string WAVE
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PATTERN_ENTRY("\xFF\xFF\xFF\xFF\x00\x00\x00\x00\xFF\xFF\xFF\xFF", "RIFF\x00\x00\x00\x00WAVE", AUDIO_WAV),
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// mp3 with ID3 tags, the string "ID3".
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PATTERN_ENTRY("\xFF\xFF\xFF", "ID3", AUDIO_MP3),
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// FLAC with standard header
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PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "fLaC", AUDIO_FLAC)
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};
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// For a complete list of file types, see http://www.ftyps.com/index.html
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nsMediaSnifferEntry sFtypEntries[] = {
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PATTERN_ENTRY("\xFF\xFF\xFF", "mp4", VIDEO_MP4), // Could be mp41 or mp42.
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PATTERN_ENTRY("\xFF\xFF\xFF", "avc", VIDEO_MP4), // Could be avc1, avc2, ...
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PATTERN_ENTRY("\xFF\xFF\xFF", "3gp", VIDEO_3GPP), // Could be 3gp4, 3gp5, ...
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PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "M4A ", AUDIO_MP4),
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PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "M4P ", AUDIO_MP4),
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PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "qt ", VIDEO_QUICKTIME),
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PATTERN_ENTRY("\xFF\xFF\xFF", "iso", VIDEO_MP4), // Could be isom or iso2.
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PATTERN_ENTRY("\xFF\xFF\xFF\xFF", "mmp4", VIDEO_MP4),
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};
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static bool MatchesBrands(const uint8_t aData[4], nsACString& aSniffedType)
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{
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for (size_t i = 0; i < mozilla::ArrayLength(sFtypEntries); ++i) {
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const auto& currentEntry = sFtypEntries[i];
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bool matched = true;
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MOZ_ASSERT(currentEntry.mLength <= 4, "Pattern is too large to match brand strings.");
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for (uint32_t j = 0; j < currentEntry.mLength; ++j) {
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if ((currentEntry.mMask[j] & aData[j]) != currentEntry.mPattern[j]) {
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matched = false;
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break;
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}
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}
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if (matched) {
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aSniffedType.AssignASCII(currentEntry.mContentType);
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return true;
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}
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}
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return false;
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}
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// This function implements sniffing algorithm for MP4 family file types,
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// including MP4 (described at http://mimesniff.spec.whatwg.org/#signature-for-mp4),
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// M4A (Apple iTunes audio), and 3GPP.
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static bool MatchesMP4(const uint8_t* aData, const uint32_t aLength, nsACString& aSniffedType)
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{
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if (aLength <= MP4_MIN_BYTES_COUNT) {
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return false;
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}
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// Conversion from big endian to host byte order.
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uint32_t boxSize = (uint32_t)(aData[3] | aData[2] << 8 | aData[1] << 16 | aData[0] << 24);
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// Boxsize should be evenly divisible by 4.
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if (boxSize % 4 || aLength < boxSize) {
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return false;
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}
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// The string "ftyp".
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if (aData[4] != 0x66 ||
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aData[5] != 0x74 ||
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aData[6] != 0x79 ||
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aData[7] != 0x70) {
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return false;
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}
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if (MatchesBrands(&aData[8], aSniffedType)) {
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return true;
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}
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// Skip minor_version (bytes 12-15).
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uint32_t bytesRead = 16;
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while (bytesRead < boxSize) {
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if (MatchesBrands(&aData[bytesRead], aSniffedType)) {
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return true;
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}
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bytesRead += 4;
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}
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return false;
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}
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static bool MatchesWebM(const uint8_t* aData, const uint32_t aLength)
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{
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return nestegg_sniff((uint8_t*)aData, aLength) ? true : false;
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}
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// This function implements mp3 sniffing based on parsing
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// packet headers and looking for expected boundaries.
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static bool MatchesMP3(const uint8_t* aData, const uint32_t aLength)
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{
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return mp3_sniff(aData, (long)aLength);
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}
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static bool MatchesFLAC(const uint8_t* aData, const uint32_t aLength)
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{
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return mozilla::FlacDemuxer::FlacSniffer(aData, aLength);
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}
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NS_IMETHODIMP
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nsMediaSniffer::GetMIMETypeFromContent(nsIRequest* aRequest,
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const uint8_t* aData,
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const uint32_t aLength,
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nsACString& aSniffedType)
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{
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nsCOMPtr<nsIChannel> channel = do_QueryInterface(aRequest);
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if (channel) {
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nsLoadFlags loadFlags = 0;
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channel->GetLoadFlags(&loadFlags);
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if (!(loadFlags & nsIChannel::LOAD_MEDIA_SNIFFER_OVERRIDES_CONTENT_TYPE)) {
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// For media, we want to sniff only if the Content-Type is unknown, or if it
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// is application/octet-stream.
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nsAutoCString contentType;
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nsresult rv = channel->GetContentType(contentType);
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NS_ENSURE_SUCCESS(rv, rv);
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if (!contentType.IsEmpty() &&
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!contentType.EqualsLiteral(APPLICATION_OCTET_STREAM) &&
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!contentType.EqualsLiteral(UNKNOWN_CONTENT_TYPE)) {
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return NS_ERROR_NOT_AVAILABLE;
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}
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}
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}
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const uint32_t clampedLength = std::min(aLength, MAX_BYTES_SNIFFED);
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for (size_t i = 0; i < mozilla::ArrayLength(sSnifferEntries); ++i) {
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const nsMediaSnifferEntry& currentEntry = sSnifferEntries[i];
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if (clampedLength < currentEntry.mLength || currentEntry.mLength == 0) {
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continue;
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}
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bool matched = true;
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for (uint32_t j = 0; j < currentEntry.mLength; ++j) {
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if ((currentEntry.mMask[j] & aData[j]) != currentEntry.mPattern[j]) {
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matched = false;
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break;
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}
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}
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if (matched) {
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aSniffedType.AssignASCII(currentEntry.mContentType);
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return NS_OK;
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}
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}
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if (MatchesMP4(aData, clampedLength, aSniffedType)) {
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return NS_OK;
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}
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if (MatchesWebM(aData, clampedLength)) {
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aSniffedType.AssignLiteral(VIDEO_WEBM);
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return NS_OK;
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}
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// Bug 950023: 512 bytes are often not enough to sniff for mp3.
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if (MatchesMP3(aData, std::min(aLength, MAX_BYTES_SNIFFED_MP3))) {
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aSniffedType.AssignLiteral(AUDIO_MP3);
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return NS_OK;
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}
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// Flac frames are generally big, often in excess of 24kB.
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// Using a size of MAX_BYTES_SNIFFED effectively means that we will only
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// recognize flac content if it starts with a frame.
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if (MatchesFLAC(aData, clampedLength)) {
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aSniffedType.AssignLiteral(AUDIO_FLAC);
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return NS_OK;
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}
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// Could not sniff the media type, we are required to set it to
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// application/octet-stream.
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aSniffedType.AssignLiteral(APPLICATION_OCTET_STREAM);
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return NS_ERROR_NOT_AVAILABLE;
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}
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