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Do not scan full MPEG file for ID3v2 tag in Fast read style (#968) (#1151)

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This is based on the patch used by VLC, but the full scan is only
skipped when the read style is explicitly set to Fast.
https://code.videolan.org/videolan/vlc/-/blob/master/contrib/src/taglib/0001-Implement-ID3v2-readStyle-avoid-worst-case.patch
This commit is contained in:
Urs Fleisch 2023-09-30 14:25:52 +02:00 committed by GitHub
parent 2154078187
commit c13a42021a
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 60 additions and 14 deletions
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21
taglib/mpeg/mpegfile.cpp
View File

@ -122,30 +122,30 @@ bool MPEG::File::isSupported(IOStream *stream)
// public members
////////////////////////////////////////////////////////////////////////////////
MPEG::File::File(FileName file, bool readProperties, Properties::ReadStyle) :
MPEG::File::File(FileName file, bool readProperties, Properties::ReadStyle readStyle) :
TagLib::File(file),
d(std::make_unique<FilePrivate>())
{
if(isOpen())
read(readProperties);
read(readProperties, readStyle);
}
MPEG::File::File(FileName file, ID3v2::FrameFactory *frameFactory,
bool readProperties, Properties::ReadStyle) :
bool readProperties, Properties::ReadStyle readStyle) :
TagLib::File(file),
d(std::make_unique<FilePrivate>(frameFactory))
{
if(isOpen())
read(readProperties);
read(readProperties, readStyle);
}
MPEG::File::File(IOStream *stream, ID3v2::FrameFactory *frameFactory,
bool readProperties, Properties::ReadStyle) :
bool readProperties, Properties::ReadStyle readStyle) :
TagLib::File(stream),
d(std::make_unique<FilePrivate>(frameFactory))
{
if(isOpen())
read(readProperties);
read(readProperties, readStyle);
}
MPEG::File::~File() = default;
@ -450,11 +450,11 @@ bool MPEG::File::hasAPETag() const
// private members
////////////////////////////////////////////////////////////////////////////////
void MPEG::File::read(bool readProperties)
void MPEG::File::read(bool readProperties, Properties::ReadStyle readStyle)
{
// Look for an ID3v2 tag
d->ID3v2Location = findID3v2();
d->ID3v2Location = findID3v2(readStyle);
if(d->ID3v2Location >= 0) {
d->tag.set(ID3v2Index, new ID3v2::Tag(this, d->ID3v2Location, d->ID3v2FrameFactory));
@ -487,7 +487,7 @@ void MPEG::File::read(bool readProperties)
ID3v1Tag(true);
}
offset_t MPEG::File::findID3v2()
offset_t MPEG::File::findID3v2(Properties::ReadStyle readStyle)
{
if(!isValid())
return -1;
@ -500,6 +500,9 @@ offset_t MPEG::File::findID3v2()
if(readBlock(headerID.size()) == headerID)
return 0;
if(readStyle == Properties::Fast)
return -1;
const Header firstHeader(this, 0, true);
if(firstHeader.isValid())
return -1;

13
taglib/mpeg/mpegfile.h
View File

@ -74,7 +74,8 @@ namespace TagLib {
* Constructs an MPEG file from \a file. If \a readProperties is true the
* file's audio properties will also be read.
*
* \note In the current implementation, \a propertiesStyle is ignored.
* If \a propertiesStyle is not Fast, the file will be scanned
* completely if no ID3v2 tag or MPEG sync code is found at the start.
*
* \deprecated This constructor will be dropped in favor of the one below
* in a future version.
@ -89,7 +90,8 @@ namespace TagLib {
* If this file contains and ID3v2 tag the frames will be created using
* \a frameFactory.
*
* \note In the current implementation, \a propertiesStyle is ignored.
* If \a propertiesStyle is not Fast, the file will be scanned
* completely if no ID3v2 tag or MPEG sync code is found at the start.
*/
// BIC: merge with the above constructor, kept for source compatibility
File(FileName file, ID3v2::FrameFactory *frameFactory,
@ -106,7 +108,8 @@ namespace TagLib {
* If this file contains and ID3v2 tag the frames will be created using
* \a frameFactory.
*
* \note In the current implementation, \a propertiesStyle is ignored.
* If \a propertiesStyle is not Fast, the file will be scanned
* completely if no ID3v2 tag or MPEG sync code is found at the start.
*/
File(IOStream *stream, ID3v2::FrameFactory *frameFactory,
bool readProperties = true,
@ -321,8 +324,8 @@ namespace TagLib {
static bool isSupported(IOStream *stream);
private:
void read(bool readProperties);
offset_t findID3v2();
void read(bool readProperties, Properties::ReadStyle readStyle);
offset_t findID3v2(Properties::ReadStyle readStyle);
class FilePrivate;
std::unique_ptr<FilePrivate> d;

40
tests/test_mpeg.cpp
View File

@ -68,6 +68,7 @@ class TestMPEG : public CppUnit::TestFixture
CPPUNIT_TEST(testEmptyAPE);
CPPUNIT_TEST(testIgnoreGarbage);
CPPUNIT_TEST(testExtendedHeader);
CPPUNIT_TEST(testReadStyleFast);
CPPUNIT_TEST_SUITE_END();
public:
@ -540,6 +541,45 @@ public:
}
}
void testReadStyleFast()
{
const ScopedFileCopy copy("lame_cbr", ".mp3");
{
MPEG::File f(copy.fileName().c_str(), true, MPEG::Properties::Fast);
CPPUNIT_ASSERT(f.audioProperties());
CPPUNIT_ASSERT_EQUAL(1887, f.audioProperties()->lengthInSeconds());
CPPUNIT_ASSERT_EQUAL(1887164, f.audioProperties()->lengthInMilliseconds());
CPPUNIT_ASSERT_EQUAL(64, f.audioProperties()->bitrate());
CPPUNIT_ASSERT_EQUAL(1, f.audioProperties()->channels());
CPPUNIT_ASSERT_EQUAL(44100, f.audioProperties()->sampleRate());
CPPUNIT_ASSERT(f.isValid());
CPPUNIT_ASSERT(f.hasID3v2Tag());
CPPUNIT_ASSERT_EQUAL(String(""), f.ID3v2Tag()->title());
PropertyMap properties = f.properties();
CPPUNIT_ASSERT_EQUAL(String("-1.020000 dB"), properties.value("REPLAYGAIN_TRACK_GAIN").front());
CPPUNIT_ASSERT_EQUAL(String("0.920032"), properties.value("REPLAYGAIN_TRACK_PEAK").front());
properties["TITLE"] = String("A Title");
properties["Artist"] = String("An Artist");
f.setProperties(properties);
f.save();
}
{
MPEG::File f(copy.fileName().c_str(), true, MPEG::Properties::Fast);
CPPUNIT_ASSERT(f.isValid());
CPPUNIT_ASSERT(f.hasID3v2Tag());
CPPUNIT_ASSERT_EQUAL(String("A Title"), f.ID3v2Tag()->title());
CPPUNIT_ASSERT_EQUAL(String("An Artist"), f.ID3v2Tag()->artist());
}
{
MPEG::File f(TEST_FILE_PATH_C("garbage.mp3"), true, MPEG::Properties::Fast);
CPPUNIT_ASSERT(f.isValid());
// Garbage prevents detection of ID3v2 with fast read style
CPPUNIT_ASSERT(!f.hasID3v2Tag());
CPPUNIT_ASSERT_EQUAL(static_cast<offset_t>(2255), f.firstFrameOffset());
CPPUNIT_ASSERT_EQUAL(static_cast<offset_t>(6015), f.lastFrameOffset());
}
}
};
CPPUNIT_TEST_SUITE_REGISTRATION(TestMPEG);