#if FOLLY_HAVE_LIBLZ4
#include <lz4.h>
#include <lz4hc.h>
+#if LZ4_VERSION_NUMBER >= 10301
+#include <lz4frame.h>
+#endif
#endif
#include <glog/logging.h>
#include <zstd.h>
#endif
+#include <folly/Bits.h>
#include <folly/Conv.h>
#include <folly/Memory.h>
#include <folly/Portability.h>
#include <folly/ScopeGuard.h>
#include <folly/Varint.h>
#include <folly/io/Cursor.h>
+#include <algorithm>
+#include <unordered_set>
namespace folly { namespace io {
return UNLIMITED_UNCOMPRESSED_LENGTH;
}
+std::vector<std::string> Codec::validPrefixes() const {
+ return {};
+}
+
+bool Codec::canUncompress(const IOBuf*, uint64_t) const {
+ return false;
+}
+
std::string Codec::doCompressString(const StringPiece data) {
const IOBuf inputBuffer{IOBuf::WRAP_BUFFER, data};
auto outputBuffer = doCompress(&inputBuffer);
#endif // FOLLY_HAVE_LIBLZ4 || FOLLY_HAVE_LIBLZMA
+namespace {
+/**
+ * Reads sizeof(T) bytes, and returns false if not enough bytes are available.
+ * Returns true if the first n bytes are equal to prefix when interpreted as
+ * a little endian T.
+ */
+template <typename T>
+typename std::enable_if<std::is_unsigned<T>::value, bool>::type
+dataStartsWithLE(const IOBuf* data, T prefix, uint64_t n = sizeof(T)) {
+ DCHECK_GT(n, 0);
+ DCHECK_LE(n, sizeof(T));
+ T value;
+ Cursor cursor{data};
+ if (!cursor.tryReadLE(value)) {
+ return false;
+ }
+ const T mask = n == sizeof(T) ? T(-1) : (T(1) << (8 * n)) - 1;
+ return prefix == (value & mask);
+}
+
+template <typename T>
+typename std::enable_if<std::is_arithmetic<T>::value, std::string>::type
+prefixToStringLE(T prefix, uint64_t n = sizeof(T)) {
+ DCHECK_GT(n, 0);
+ DCHECK_LE(n, sizeof(T));
+ prefix = Endian::little(prefix);
+ std::string result;
+ result.resize(n);
+ memcpy(&result[0], &prefix, n);
+ return result;
+}
+} // namespace
+
#if FOLLY_HAVE_LIBLZ4
/**
}
std::unique_ptr<IOBuf> LZ4Codec::doCompress(const IOBuf* data) {
- std::unique_ptr<IOBuf> clone;
+ IOBuf clone;
if (data->isChained()) {
// LZ4 doesn't support streaming, so we have to coalesce
- clone = data->clone();
- clone->coalesce();
- data = clone.get();
+ clone = data->cloneCoalescedAsValue();
+ data = &clone;
}
uint32_t extraSize = encodeSize() ? kMaxVarintLength64 : 0;
std::unique_ptr<IOBuf> LZ4Codec::doUncompress(
const IOBuf* data,
uint64_t uncompressedLength) {
- std::unique_ptr<IOBuf> clone;
+ IOBuf clone;
if (data->isChained()) {
// LZ4 doesn't support streaming, so we have to coalesce
- clone = data->clone();
- clone->coalesce();
- data = clone.get();
+ clone = data->cloneCoalescedAsValue();
+ data = &clone;
}
folly::io::Cursor cursor(data);
return out;
}
-#endif // FOLLY_HAVE_LIBLZ4
+#if LZ4_VERSION_NUMBER >= 10301
+
+class LZ4FrameCodec final : public Codec {
+ public:
+ static std::unique_ptr<Codec> create(int level, CodecType type);
+ explicit LZ4FrameCodec(int level, CodecType type);
+ ~LZ4FrameCodec();
+
+ std::vector<std::string> validPrefixes() const override;
+ bool canUncompress(const IOBuf* data, uint64_t uncompressedLength)
+ const override;
+
+ private:
+ std::unique_ptr<IOBuf> doCompress(const IOBuf* data) override;
+ std::unique_ptr<IOBuf> doUncompress(
+ const IOBuf* data,
+ uint64_t uncompressedLength) override;
+
+ // Reset the dctx_ if it is dirty or null.
+ void resetDCtx();
+
+ int level_;
+ LZ4F_decompressionContext_t dctx_{nullptr};
+ bool dirty_{false};
+};
+
+/* static */ std::unique_ptr<Codec> LZ4FrameCodec::create(
+ int level,
+ CodecType type) {
+ return make_unique<LZ4FrameCodec>(level, type);
+}
+
+static constexpr uint32_t kLZ4FrameMagicLE = 0x184D2204;
+
+std::vector<std::string> LZ4FrameCodec::validPrefixes() const {
+ return {prefixToStringLE(kLZ4FrameMagicLE)};
+}
+
+bool LZ4FrameCodec::canUncompress(const IOBuf* data, uint64_t) const {
+ return dataStartsWithLE(data, kLZ4FrameMagicLE);
+}
+
+static size_t lz4FrameThrowOnError(size_t code) {
+ if (LZ4F_isError(code)) {
+ throw std::runtime_error(
+ to<std::string>("LZ4Frame error: ", LZ4F_getErrorName(code)));
+ }
+ return code;
+}
+
+void LZ4FrameCodec::resetDCtx() {
+ if (dctx_ && !dirty_) {
+ return;
+ }
+ if (dctx_) {
+ LZ4F_freeDecompressionContext(dctx_);
+ }
+ lz4FrameThrowOnError(LZ4F_createDecompressionContext(&dctx_, 100));
+ dirty_ = false;
+}
+
+LZ4FrameCodec::LZ4FrameCodec(int level, CodecType type) : Codec(type) {
+ DCHECK(type == CodecType::LZ4_FRAME);
+ switch (level) {
+ case COMPRESSION_LEVEL_FASTEST:
+ case COMPRESSION_LEVEL_DEFAULT:
+ level_ = 0;
+ break;
+ case COMPRESSION_LEVEL_BEST:
+ level_ = 16;
+ break;
+ default:
+ level_ = level;
+ break;
+ }
+}
+
+LZ4FrameCodec::~LZ4FrameCodec() {
+ if (dctx_) {
+ LZ4F_freeDecompressionContext(dctx_);
+ }
+}
+
+std::unique_ptr<IOBuf> LZ4FrameCodec::doCompress(const IOBuf* data) {
+ // LZ4 Frame compression doesn't support streaming so we have to coalesce
+ IOBuf clone;
+ if (data->isChained()) {
+ clone = data->cloneCoalescedAsValue();
+ data = &clone;
+ }
+ // Set preferences
+ const auto uncompressedLength = data->length();
+ LZ4F_preferences_t prefs{};
+ prefs.compressionLevel = level_;
+ prefs.frameInfo.contentSize = uncompressedLength;
+ // Compress
+ auto buf = IOBuf::create(LZ4F_compressFrameBound(uncompressedLength, &prefs));
+ const size_t written = lz4FrameThrowOnError(LZ4F_compressFrame(
+ buf->writableTail(),
+ buf->tailroom(),
+ data->data(),
+ data->length(),
+ &prefs));
+ buf->append(written);
+ return buf;
+}
+
+std::unique_ptr<IOBuf> LZ4FrameCodec::doUncompress(
+ const IOBuf* data,
+ uint64_t uncompressedLength) {
+ // Reset the dctx if any errors have occurred
+ resetDCtx();
+ // Coalesce the data
+ ByteRange in = *data->begin();
+ IOBuf clone;
+ if (data->isChained()) {
+ clone = data->cloneCoalescedAsValue();
+ in = clone.coalesce();
+ }
+ data = nullptr;
+ // Select decompression options
+ LZ4F_decompressOptions_t options;
+ options.stableDst = 1;
+ // Select blockSize and growthSize for the IOBufQueue
+ IOBufQueue queue(IOBufQueue::cacheChainLength());
+ auto blockSize = uint64_t{64} << 10;
+ auto growthSize = uint64_t{4} << 20;
+ if (uncompressedLength != UNKNOWN_UNCOMPRESSED_LENGTH) {
+ // Allocate uncompressedLength in one chunk (up to 64 MB)
+ const auto allocateSize = std::min(uncompressedLength, uint64_t{64} << 20);
+ queue.preallocate(allocateSize, allocateSize);
+ blockSize = std::min(uncompressedLength, blockSize);
+ growthSize = std::min(uncompressedLength, growthSize);
+ } else {
+ // Reduce growthSize for small data
+ const auto guessUncompressedLen =
+ 4 * std::max<uint64_t>(blockSize, in.size());
+ growthSize = std::min(guessUncompressedLen, growthSize);
+ }
+ // Once LZ4_decompress() is called, the dctx_ cannot be reused until it
+ // returns 0
+ dirty_ = true;
+ // Decompress until the frame is over
+ size_t code = 0;
+ do {
+ // Allocate enough space to decompress at least a block
+ void* out;
+ size_t outSize;
+ std::tie(out, outSize) = queue.preallocate(blockSize, growthSize);
+ // Decompress
+ size_t inSize = in.size();
+ code = lz4FrameThrowOnError(
+ LZ4F_decompress(dctx_, out, &outSize, in.data(), &inSize, &options));
+ if (in.empty() && outSize == 0 && code != 0) {
+ // We passed no input, no output was produced, and the frame isn't over
+ // No more forward progress is possible
+ throw std::runtime_error("LZ4Frame error: Incomplete frame");
+ }
+ in.uncheckedAdvance(inSize);
+ queue.postallocate(outSize);
+ } while (code != 0);
+ // At this point the decompression context can be reused
+ dirty_ = false;
+ if (uncompressedLength != UNKNOWN_UNCOMPRESSED_LENGTH &&
+ queue.chainLength() != uncompressedLength) {
+ throw std::runtime_error("LZ4Frame error: Invalid uncompressedLength");
+ }
+ return queue.move();
+}
+
+#endif // LZ4_VERSION_NUMBER >= 10301
+#endif // FOLLY_HAVE_LIBLZ4
#if FOLLY_HAVE_LIBSNAPPY
static std::unique_ptr<Codec> create(int level, CodecType type);
explicit ZlibCodec(int level, CodecType type);
+ std::vector<std::string> validPrefixes() const override;
+ bool canUncompress(const IOBuf* data, uint64_t uncompressedLength)
+ const override;
+
private:
std::unique_ptr<IOBuf> doCompress(const IOBuf* data) override;
std::unique_ptr<IOBuf> doUncompress(
int level_;
};
+static constexpr uint16_t kGZIPMagicLE = 0x8B1F;
+
+std::vector<std::string> ZlibCodec::validPrefixes() const {
+ if (type() == CodecType::ZLIB) {
+ // Zlib streams start with a 2 byte header.
+ //
+ // 0 1
+ // +---+---+
+ // |CMF|FLG|
+ // +---+---+
+ //
+ // We won't restrict the values of any sub-fields except as described below.
+ //
+ // The lowest 4 bits of CMF is the compression method (CM).
+ // CM == 0x8 is the deflate compression method, which is currently the only
+ // supported compression method, so any valid prefix must have CM == 0x8.
+ //
+ // The lowest 5 bits of FLG is FCHECK.
+ // FCHECK must be such that the two header bytes are a multiple of 31 when
+ // interpreted as a big endian 16-bit number.
+ std::vector<std::string> result;
+ // 16 values for the first byte, 8 values for the second byte.
+ // There are also 4 combinations where both 0x00 and 0x1F work as FCHECK.
+ result.reserve(132);
+ // Select all values for the CMF byte that use the deflate algorithm 0x8.
+ for (uint32_t first = 0x0800; first <= 0xF800; first += 0x1000) {
+ // Select all values for the FLG, but leave FCHECK as 0 since it's fixed.
+ for (uint32_t second = 0x00; second <= 0xE0; second += 0x20) {
+ uint16_t prefix = first | second;
+ // Compute FCHECK.
+ prefix += 31 - (prefix % 31);
+ result.push_back(prefixToStringLE(Endian::big(prefix)));
+ // zlib won't produce this, but it is a valid prefix.
+ if ((prefix & 0x1F) == 31) {
+ prefix -= 31;
+ result.push_back(prefixToStringLE(Endian::big(prefix)));
+ }
+ }
+ }
+ return result;
+ } else {
+ // The gzip frame starts with 2 magic bytes.
+ return {prefixToStringLE(kGZIPMagicLE)};
+ }
+}
+
+bool ZlibCodec::canUncompress(const IOBuf* data, uint64_t) const {
+ if (type() == CodecType::ZLIB) {
+ uint16_t value;
+ Cursor cursor{data};
+ if (!cursor.tryReadBE(value)) {
+ return false;
+ }
+ // zlib compressed if using deflate and is a multiple of 31.
+ return (value & 0x0F00) == 0x0800 && value % 31 == 0;
+ } else {
+ return dataStartsWithLE(data, kGZIPMagicLE);
+ }
+}
+
std::unique_ptr<Codec> ZlibCodec::create(int level, CodecType type) {
return make_unique<ZlibCodec>(level, type);
}
return out;
}
+static uint64_t computeBufferLength(uint64_t const compressedLength) {
+ constexpr uint64_t kMaxBufferLength = uint64_t(4) << 20; // 4 MiB
+ constexpr uint64_t kBlockSize = uint64_t(32) << 10; // 32 KiB
+ const uint64_t goodBufferSize = 4 * std::max(kBlockSize, compressedLength);
+ return std::min(goodBufferSize, kMaxBufferLength);
+}
+
std::unique_ptr<IOBuf> ZlibCodec::doUncompress(const IOBuf* data,
uint64_t uncompressedLength) {
z_stream stream;
};
// Max 64MiB in one go
- constexpr uint32_t maxSingleStepLength = uint32_t(64) << 20; // 64MiB
- constexpr uint32_t defaultBufferLength = uint32_t(4) << 20; // 4MiB
+ constexpr uint64_t maxSingleStepLength = uint64_t(64) << 20; // 64MiB
+ const uint64_t defaultBufferLength =
+ computeBufferLength(data->computeChainDataLength());
auto out = addOutputBuffer(
&stream,
static std::unique_ptr<Codec> create(int level, CodecType type);
explicit LZMA2Codec(int level, CodecType type);
+ std::vector<std::string> validPrefixes() const override;
+ bool canUncompress(const IOBuf* data, uint64_t uncompressedLength)
+ const override;
+
private:
bool doNeedsUncompressedLength() const override;
uint64_t doMaxUncompressedLength() const override;
int level_;
};
+static constexpr uint64_t kLZMA2MagicLE = 0x005A587A37FD;
+static constexpr unsigned kLZMA2MagicBytes = 6;
+
+std::vector<std::string> LZMA2Codec::validPrefixes() const {
+ if (type() == CodecType::LZMA2_VARINT_SIZE) {
+ return {};
+ }
+ return {prefixToStringLE(kLZMA2MagicLE, kLZMA2MagicBytes)};
+}
+
+bool LZMA2Codec::canUncompress(const IOBuf* data, uint64_t) const {
+ if (type() == CodecType::LZMA2_VARINT_SIZE) {
+ return false;
+ }
+ // Returns false for all inputs less than 8 bytes.
+ // This is okay, because no valid LZMA2 streams are less than 8 bytes.
+ return dataStartsWithLE(data, kLZMA2MagicLE, kLZMA2MagicBytes);
+}
+
std::unique_ptr<Codec> LZMA2Codec::create(int level, CodecType type) {
return make_unique<LZMA2Codec>(level, type);
}
}
bool LZMA2Codec::doNeedsUncompressedLength() const {
- return !encodeSize();
+ return false;
}
uint64_t LZMA2Codec::doMaxUncompressedLength() const {
SCOPE_EXIT { lzma_end(&stream); };
// Max 64MiB in one go
- constexpr uint32_t maxSingleStepLength = uint32_t(64) << 20; // 64MiB
- constexpr uint32_t defaultBufferLength = uint32_t(4) << 20; // 4MiB
+ constexpr uint32_t maxSingleStepLength = uint32_t(64) << 20; // 64MiB
+ constexpr uint32_t defaultBufferLength = uint32_t(256) << 10; // 256 KiB
folly::io::Cursor cursor(data);
- uint64_t actualUncompressedLength;
if (encodeSize()) {
- actualUncompressedLength = decodeVarintFromCursor(cursor);
+ const uint64_t actualUncompressedLength = decodeVarintFromCursor(cursor);
if (uncompressedLength != UNKNOWN_UNCOMPRESSED_LENGTH &&
uncompressedLength != actualUncompressedLength) {
throw std::runtime_error("LZMA2Codec: invalid uncompressed length");
}
- } else {
- actualUncompressedLength = uncompressedLength;
- DCHECK_NE(actualUncompressedLength, UNKNOWN_UNCOMPRESSED_LENGTH);
+ uncompressedLength = actualUncompressedLength;
}
auto out = addOutputBuffer(
&stream,
- (actualUncompressedLength <= maxSingleStepLength ?
- actualUncompressedLength :
- defaultBufferLength));
+ ((uncompressedLength != UNKNOWN_UNCOMPRESSED_LENGTH &&
+ uncompressedLength <= maxSingleStepLength)
+ ? uncompressedLength
+ : defaultBufferLength));
bool streamEnd = false;
auto buf = cursor.peekBytes();
out->prev()->trimEnd(stream.avail_out);
- if (actualUncompressedLength != stream.total_out) {
- throw std::runtime_error(to<std::string>(
- "LZMA2Codec: invalid uncompressed length"));
+ if (uncompressedLength != UNKNOWN_UNCOMPRESSED_LENGTH &&
+ uncompressedLength != stream.total_out) {
+ throw std::runtime_error(
+ to<std::string>("LZMA2Codec: invalid uncompressed length"));
}
return out;
static std::unique_ptr<Codec> create(int level, CodecType);
explicit ZSTDCodec(int level, CodecType type);
+ std::vector<std::string> validPrefixes() const override;
+ bool canUncompress(const IOBuf* data, uint64_t uncompressedLength)
+ const override;
+
private:
bool doNeedsUncompressedLength() const override;
std::unique_ptr<IOBuf> doCompress(const IOBuf* data) override;
int level_;
};
+static constexpr uint32_t kZSTDMagicLE = 0xFD2FB528;
+
+std::vector<std::string> ZSTDCodec::validPrefixes() const {
+ return {prefixToStringLE(kZSTDMagicLE)};
+}
+
+bool ZSTDCodec::canUncompress(const IOBuf* data, uint64_t) const {
+ return dataStartsWithLE(data, kZSTDMagicLE);
+}
+
std::unique_ptr<Codec> ZSTDCodec::create(int level, CodecType type) {
return make_unique<ZSTDCodec>(level, type);
}
return result;
}
-std::unique_ptr<IOBuf> ZSTDCodec::doUncompress(
+static std::unique_ptr<IOBuf> zstdUncompressBuffer(
+ const IOBuf* data,
+ uint64_t uncompressedLength) {
+ // Check preconditions
+ DCHECK(!data->isChained());
+ DCHECK(uncompressedLength != Codec::UNKNOWN_UNCOMPRESSED_LENGTH);
+
+ auto uncompressed = IOBuf::create(uncompressedLength);
+ const auto decompressedSize = ZSTD_decompress(
+ uncompressed->writableTail(),
+ uncompressed->tailroom(),
+ data->data(),
+ data->length());
+ zstdThrowIfError(decompressedSize);
+ if (decompressedSize != uncompressedLength) {
+ throw std::runtime_error("ZSTD: invalid uncompressed length");
+ }
+ uncompressed->append(decompressedSize);
+ return uncompressed;
+}
+
+static std::unique_ptr<IOBuf> zstdUncompressStream(
const IOBuf* data,
uint64_t uncompressedLength) {
auto zds = ZSTD_createDStream();
ZSTD_inBuffer in{};
auto outputSize = ZSTD_DStreamOutSize();
- if (uncompressedLength != UNKNOWN_UNCOMPRESSED_LENGTH) {
+ if (uncompressedLength != Codec::UNKNOWN_UNCOMPRESSED_LENGTH) {
outputSize = uncompressedLength;
- } else {
- auto decompressedSize =
- ZSTD_getDecompressedSize(data->data(), data->length());
- if (decompressedSize != 0 && decompressedSize < outputSize) {
- outputSize = decompressedSize;
- }
}
IOBufQueue queue(IOBufQueue::cacheChainLength());
if (in.pos != in.size || !cursor.isAtEnd()) {
throw std::runtime_error("ZSTD: junk after end of data");
}
- if (uncompressedLength != UNKNOWN_UNCOMPRESSED_LENGTH &&
+ if (uncompressedLength != Codec::UNKNOWN_UNCOMPRESSED_LENGTH &&
queue.chainLength() != uncompressedLength) {
throw std::runtime_error("ZSTD: invalid uncompressed length");
}
return queue.move();
}
+std::unique_ptr<IOBuf> ZSTDCodec::doUncompress(
+ const IOBuf* data,
+ uint64_t uncompressedLength) {
+ {
+ // Read decompressed size from frame if available in first IOBuf.
+ const auto decompressedSize =
+ ZSTD_getDecompressedSize(data->data(), data->length());
+ if (decompressedSize != 0) {
+ if (uncompressedLength != Codec::UNKNOWN_UNCOMPRESSED_LENGTH &&
+ uncompressedLength != decompressedSize) {
+ throw std::runtime_error("ZSTD: invalid uncompressed length");
+ }
+ uncompressedLength = decompressedSize;
+ }
+ }
+ // Faster to decompress using ZSTD_decompress() if we can.
+ if (uncompressedLength != UNKNOWN_UNCOMPRESSED_LENGTH && !data->isChained()) {
+ return zstdUncompressBuffer(data, uncompressedLength);
+ }
+ // Fall back to slower streaming decompression.
+ return zstdUncompressStream(data, uncompressedLength);
+}
+
#endif // FOLLY_HAVE_LIBZSTD
+/**
+ * Automatic decompression
+ */
+class AutomaticCodec final : public Codec {
+ public:
+ static std::unique_ptr<Codec> create(
+ std::vector<std::unique_ptr<Codec>> customCodecs);
+ explicit AutomaticCodec(std::vector<std::unique_ptr<Codec>> customCodecs);
+
+ std::vector<std::string> validPrefixes() const override;
+ bool canUncompress(const IOBuf* data, uint64_t uncompressedLength)
+ const override;
+
+ private:
+ bool doNeedsUncompressedLength() const override;
+ uint64_t doMaxUncompressedLength() const override;
+
+ std::unique_ptr<IOBuf> doCompress(const IOBuf*) override {
+ throw std::runtime_error("AutomaticCodec error: compress() not supported.");
+ }
+ std::unique_ptr<IOBuf> doUncompress(
+ const IOBuf* data,
+ uint64_t uncompressedLength) override;
+
+ void addCodecIfSupported(CodecType type);
+
+ // Throws iff the codecs aren't compatible (very slow)
+ void checkCompatibleCodecs() const;
+
+ std::vector<std::unique_ptr<Codec>> codecs_;
+ bool needsUncompressedLength_;
+ uint64_t maxUncompressedLength_;
+};
+
+std::vector<std::string> AutomaticCodec::validPrefixes() const {
+ std::unordered_set<std::string> prefixes;
+ for (const auto& codec : codecs_) {
+ const auto codecPrefixes = codec->validPrefixes();
+ prefixes.insert(codecPrefixes.begin(), codecPrefixes.end());
+ }
+ return std::vector<std::string>{prefixes.begin(), prefixes.end()};
+}
+
+bool AutomaticCodec::canUncompress(
+ const IOBuf* data,
+ uint64_t uncompressedLength) const {
+ return std::any_of(
+ codecs_.begin(),
+ codecs_.end(),
+ [data, uncompressedLength](std::unique_ptr<Codec> const& codec) {
+ return codec->canUncompress(data, uncompressedLength);
+ });
+}
+
+void AutomaticCodec::addCodecIfSupported(CodecType type) {
+ const bool present = std::any_of(
+ codecs_.begin(),
+ codecs_.end(),
+ [&type](std::unique_ptr<Codec> const& codec) {
+ return codec->type() == type;
+ });
+ if (hasCodec(type) && !present) {
+ codecs_.push_back(getCodec(type));
+ }
+}
+
+/* static */ std::unique_ptr<Codec> AutomaticCodec::create(
+ std::vector<std::unique_ptr<Codec>> customCodecs) {
+ return make_unique<AutomaticCodec>(std::move(customCodecs));
+}
+
+AutomaticCodec::AutomaticCodec(std::vector<std::unique_ptr<Codec>> customCodecs)
+ : Codec(CodecType::USER_DEFINED), codecs_(std::move(customCodecs)) {
+ // Fastest -> slowest
+ addCodecIfSupported(CodecType::LZ4_FRAME);
+ addCodecIfSupported(CodecType::ZSTD);
+ addCodecIfSupported(CodecType::ZLIB);
+ addCodecIfSupported(CodecType::GZIP);
+ addCodecIfSupported(CodecType::LZMA2);
+ if (kIsDebug) {
+ checkCompatibleCodecs();
+ }
+ // Check that none of the codes are are null
+ DCHECK(std::none_of(
+ codecs_.begin(), codecs_.end(), [](std::unique_ptr<Codec> const& codec) {
+ return codec == nullptr;
+ }));
+
+ needsUncompressedLength_ = std::any_of(
+ codecs_.begin(), codecs_.end(), [](std::unique_ptr<Codec> const& codec) {
+ return codec->needsUncompressedLength();
+ });
+
+ const auto it = std::max_element(
+ codecs_.begin(),
+ codecs_.end(),
+ [](std::unique_ptr<Codec> const& lhs, std::unique_ptr<Codec> const& rhs) {
+ return lhs->maxUncompressedLength() < rhs->maxUncompressedLength();
+ });
+ DCHECK(it != codecs_.end());
+ maxUncompressedLength_ = (*it)->maxUncompressedLength();
+}
+
+void AutomaticCodec::checkCompatibleCodecs() const {
+ // Keep track of all the possible headers.
+ std::unordered_set<std::string> headers;
+ // The empty header is not allowed.
+ headers.insert("");
+ // Step 1:
+ // Construct a set of headers and check that none of the headers occur twice.
+ // Eliminate edge cases.
+ for (auto&& codec : codecs_) {
+ const auto codecHeaders = codec->validPrefixes();
+ // Codecs without any valid headers are not allowed.
+ if (codecHeaders.empty()) {
+ throw std::invalid_argument{
+ "AutomaticCodec: validPrefixes() must not be empty."};
+ }
+ // Insert all the headers for the current codec.
+ const size_t beforeSize = headers.size();
+ headers.insert(codecHeaders.begin(), codecHeaders.end());
+ // Codecs are not compatible if any header occurred twice.
+ if (beforeSize + codecHeaders.size() != headers.size()) {
+ throw std::invalid_argument{
+ "AutomaticCodec: Two valid prefixes collide."};
+ }
+ }
+ // Step 2:
+ // Check if any strict non-empty prefix of any header is a header.
+ for (const auto& header : headers) {
+ for (size_t i = 1; i < header.size(); ++i) {
+ if (headers.count(header.substr(0, i))) {
+ throw std::invalid_argument{
+ "AutomaticCodec: One valid prefix is a prefix of another valid "
+ "prefix."};
+ }
+ }
+ }
+}
+
+bool AutomaticCodec::doNeedsUncompressedLength() const {
+ return needsUncompressedLength_;
+}
+
+uint64_t AutomaticCodec::doMaxUncompressedLength() const {
+ return maxUncompressedLength_;
+}
+
+std::unique_ptr<IOBuf> AutomaticCodec::doUncompress(
+ const IOBuf* data,
+ uint64_t uncompressedLength) {
+ for (auto&& codec : codecs_) {
+ if (codec->canUncompress(data, uncompressedLength)) {
+ return codec->uncompress(data, uncompressedLength);
+ }
+ }
+ throw std::runtime_error("AutomaticCodec error: Unknown compressed data");
+}
+
} // namespace
typedef std::unique_ptr<Codec> (*CodecFactory)(int, CodecType);
-static CodecFactory
+static constexpr CodecFactory
codecFactories[static_cast<size_t>(CodecType::NUM_CODEC_TYPES)] = {
nullptr, // USER_DEFINED
NoCompressionCodec::create,
#else
nullptr,
#endif
+
+#if (FOLLY_HAVE_LIBLZ4 && LZ4_VERSION_NUMBER >= 10301)
+ LZ4FrameCodec::create,
+#else
+ nullptr,
+#endif
};
bool hasCodec(CodecType type) {
return codec;
}
+std::unique_ptr<Codec> getAutoUncompressionCodec(
+ std::vector<std::unique_ptr<Codec>> customCodecs) {
+ return AutomaticCodec::create(std::move(customCodecs));
+}
}} // namespaces
projects / folly.git / blobdiff