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rocksdb/table/format.cc

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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "table/format.h"
#include <string>
#include <inttypes.h>
#include "port/port.h"
#include "rocksdb/env.h"
#include "table/block.h"
#include "util/coding.h"
#include "util/crc32c.h"
#include "util/perf_context_imp.h"
namespace rocksdb {
void BlockHandle::EncodeTo(std::string* dst) const {
// Sanity check that all fields have been set
assert(offset_ != ~static_cast<uint64_t>(0));
assert(size_ != ~static_cast<uint64_t>(0));
PutVarint64(dst, offset_);
PutVarint64(dst, size_);
}
Status BlockHandle::DecodeFrom(Slice* input) {
if (GetVarint64(input, &offset_) &&
GetVarint64(input, &size_)) {
return Status::OK();
} else {
return Status::Corruption("bad block handle");
}
}
const BlockHandle BlockHandle::kNullBlockHandle(0, 0);
void Footer::EncodeTo(std::string* dst) const {
#ifndef NDEBUG
const size_t original_size = dst->size();
#endif
metaindex_handle_.EncodeTo(dst);
index_handle_.EncodeTo(dst);
dst->resize(2 * BlockHandle::kMaxEncodedLength); // Padding
PutFixed32(dst, static_cast<uint32_t>(table_magic_number() & 0xffffffffu));
PutFixed32(dst, static_cast<uint32_t>(table_magic_number() >> 32));
assert(dst->size() == original_size + kEncodedLength);
}
Status Footer::DecodeFrom(Slice* input) {
assert(input != nullptr);
assert(input->size() >= kEncodedLength);
const char* magic_ptr =
input->data() + kEncodedLength - kMagicNumberLengthByte;
const uint32_t magic_lo = DecodeFixed32(magic_ptr);
const uint32_t magic_hi = DecodeFixed32(magic_ptr + 4);
const uint64_t magic = ((static_cast<uint64_t>(magic_hi) << 32) |
(static_cast<uint64_t>(magic_lo)));
if (HasInitializedTableMagicNumber()) {
if (magic != table_magic_number()) {
char buffer[80];
snprintf(buffer, sizeof(buffer) - 1,
"not an sstable (bad magic number --- %lx)",
(long)magic);
return Status::InvalidArgument(buffer);
}
} else {
set_table_magic_number(magic);
}
Status result = metaindex_handle_.DecodeFrom(input);
if (result.ok()) {
result = index_handle_.DecodeFrom(input);
}
if (result.ok()) {
// We skip over any leftover data (just padding for now) in "input"
const char* end = magic_ptr + 8;
*input = Slice(end, input->data() + input->size() - end);
}
return result;
}
Status ReadFooterFromFile(RandomAccessFile* file,
uint64_t file_size,
Footer* footer) {
if (file_size < Footer::kEncodedLength) {
return Status::InvalidArgument("file is too short to be an sstable");
}
char footer_space[Footer::kEncodedLength];
Slice footer_input;
Status s = file->Read(file_size - Footer::kEncodedLength,
Footer::kEncodedLength,
&footer_input,
footer_space);
if (!s.ok()) return s;
// Check that we actually read the whole footer from the file. It may be
// that size isn't correct.
if (footer_input.size() != Footer::kEncodedLength) {
return Status::InvalidArgument("file is too short to be an sstable");
}
return footer->DecodeFrom(&footer_input);
}
Status ReadBlockContents(RandomAccessFile* file,
const ReadOptions& options,
const BlockHandle& handle,
BlockContents* result,
Env* env,
bool do_uncompress) {
result->data = Slice();
result->cachable = false;
result->heap_allocated = false;
// Read the block contents as well as the type/crc footer.
// See table_builder.cc for the code that built this structure.
size_t n = static_cast<size_t>(handle.size());
char* buf = new char[n + kBlockTrailerSize];
Slice contents;
PERF_TIMER_AUTO(block_read_time);
Status s = file->Read(handle.offset(), n + kBlockTrailerSize, &contents, buf);
PERF_TIMER_MEASURE(block_read_time);
PERF_COUNTER_ADD(block_read_count, 1);
PERF_COUNTER_ADD(block_read_byte, n + kBlockTrailerSize);
if (!s.ok()) {
delete[] buf;
return s;
}
if (contents.size() != n + kBlockTrailerSize) {
delete[] buf;
return Status::Corruption("truncated block read");
}
// Check the crc of the type and the block contents
const char* data = contents.data(); // Pointer to where Read put the data
if (options.verify_checksums) {
const uint32_t crc = crc32c::Unmask(DecodeFixed32(data + n + 1));
const uint32_t actual = crc32c::Value(data, n + 1);
if (actual != crc) {
delete[] buf;
s = Status::Corruption("block checksum mismatch");
return s;
}
PERF_TIMER_MEASURE(block_checksum_time);
}
// If the caller has requested that the block not be uncompressed
if (!do_uncompress || data[n] == kNoCompression) {
if (data != buf) {
// File implementation gave us pointer to some other data.
// Use it directly under the assumption that it will be live
// while the file is open.
delete[] buf;
result->data = Slice(data, n);
result->heap_allocated = false;
result->cachable = false; // Do not double-cache
} else {
result->data = Slice(buf, n);
result->heap_allocated = true;
result->cachable = true;
}
result->compression_type = (rocksdb::CompressionType)data[n];
s = Status::OK();
} else {
s = UncompressBlockContents(data, n, result);
delete[] buf;
}
PERF_TIMER_STOP(block_decompress_time);
return s;
}
//
// The 'data' points to the raw block contents that was read in from file.
// This method allocates a new heap buffer and the raw block
// contents are uncompresed into this buffer. This
// buffer is returned via 'result' and it is upto the caller to
// free this buffer.
Status UncompressBlockContents(const char* data, size_t n,
BlockContents* result) {
char* ubuf = nullptr;
int decompress_size = 0;
assert(data[n] != kNoCompression);
switch (data[n]) {
case kSnappyCompression: {
size_t ulength = 0;
static char snappy_corrupt_msg[] =
"Snappy not supported or corrupted Snappy compressed block contents";
if (!port::Snappy_GetUncompressedLength(data, n, &ulength)) {
return Status::Corruption(snappy_corrupt_msg);
}
ubuf = new char[ulength];
if (!port::Snappy_Uncompress(data, n, ubuf)) {
delete[] ubuf;
return Status::Corruption(snappy_corrupt_msg);
}
result->data = Slice(ubuf, ulength);
result->heap_allocated = true;
result->cachable = true;
break;
}
case kZlibCompression:
ubuf = port::Zlib_Uncompress(data, n, &decompress_size);
static char zlib_corrupt_msg[] =
"Zlib not supported or corrupted Zlib compressed block contents";
if (!ubuf) {
return Status::Corruption(zlib_corrupt_msg);
}
result->data = Slice(ubuf, decompress_size);
result->heap_allocated = true;
result->cachable = true;
break;
case kBZip2Compression:
ubuf = port::BZip2_Uncompress(data, n, &decompress_size);
static char bzip2_corrupt_msg[] =
"Bzip2 not supported or corrupted Bzip2 compressed block contents";
if (!ubuf) {
return Status::Corruption(bzip2_corrupt_msg);
}
result->data = Slice(ubuf, decompress_size);
result->heap_allocated = true;
result->cachable = true;
break;
case kLZ4Compression:
ubuf = port::LZ4_Uncompress(data, n, &decompress_size);
static char lz4_corrupt_msg[] =
"LZ4 not supported or corrupted LZ4 compressed block contents";
if (!ubuf) {
return Status::Corruption(lz4_corrupt_msg);
}
result->data = Slice(ubuf, decompress_size);
result->heap_allocated = true;
result->cachable = true;
break;
case kLZ4HCCompression:
ubuf = port::LZ4_Uncompress(data, n, &decompress_size);
static char lz4hc_corrupt_msg[] =
"LZ4HC not supported or corrupted LZ4HC compressed block contents";
if (!ubuf) {
return Status::Corruption(lz4hc_corrupt_msg);
}
result->data = Slice(ubuf, decompress_size);
result->heap_allocated = true;
result->cachable = true;
break;
default:
return Status::Corruption("bad block type");
}
result->compression_type = kNoCompression; // not compressed any more
return Status::OK();
}
} // namespace rocksdb
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