219b35be6a
Summary: Generalizing this process will help us to re-use the code for plain table Test Plan: ran ./table_test
229 lines
7.8 KiB
C++
229 lines
7.8 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include "table/format.h"
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#include "port/port.h"
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#include "rocksdb/env.h"
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#include "table/block.h"
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#include "util/coding.h"
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#include "util/crc32c.h"
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#include "util/perf_context_imp.h"
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namespace rocksdb {
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void BlockHandle::EncodeTo(std::string* dst) const {
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// Sanity check that all fields have been set
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assert(offset_ != ~static_cast<uint64_t>(0));
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assert(size_ != ~static_cast<uint64_t>(0));
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PutVarint64(dst, offset_);
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PutVarint64(dst, size_);
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}
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Status BlockHandle::DecodeFrom(Slice* input) {
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if (GetVarint64(input, &offset_) &&
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GetVarint64(input, &size_)) {
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return Status::OK();
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} else {
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return Status::Corruption("bad block handle");
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}
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}
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const BlockHandle BlockHandle::kNullBlockHandle(0, 0);
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void Footer::EncodeTo(std::string* dst) const {
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#ifndef NDEBUG
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const size_t original_size = dst->size();
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#endif
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metaindex_handle_.EncodeTo(dst);
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index_handle_.EncodeTo(dst);
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dst->resize(2 * BlockHandle::kMaxEncodedLength); // Padding
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PutFixed32(dst, static_cast<uint32_t>(kTableMagicNumber & 0xffffffffu));
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PutFixed32(dst, static_cast<uint32_t>(kTableMagicNumber >> 32));
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assert(dst->size() == original_size + kEncodedLength);
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}
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Status Footer::DecodeFrom(Slice* input) {
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assert(input != nullptr);
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assert(input->size() >= kEncodedLength);
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const char* magic_ptr = input->data() + kEncodedLength - 8;
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const uint32_t magic_lo = DecodeFixed32(magic_ptr);
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const uint32_t magic_hi = DecodeFixed32(magic_ptr + 4);
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const uint64_t magic = ((static_cast<uint64_t>(magic_hi) << 32) |
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(static_cast<uint64_t>(magic_lo)));
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if (magic != kTableMagicNumber) {
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return Status::InvalidArgument("not an sstable (bad magic number)");
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}
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Status result = metaindex_handle_.DecodeFrom(input);
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if (result.ok()) {
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result = index_handle_.DecodeFrom(input);
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}
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if (result.ok()) {
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// We skip over any leftover data (just padding for now) in "input"
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const char* end = magic_ptr + 8;
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*input = Slice(end, input->data() + input->size() - end);
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}
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return result;
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}
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Status ReadFooterFromFile(RandomAccessFile* file,
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uint64_t file_size,
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Footer* footer) {
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if (file_size < Footer::kEncodedLength) {
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return Status::InvalidArgument("file is too short to be an sstable");
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}
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char footer_space[Footer::kEncodedLength];
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Slice footer_input;
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Status s = file->Read(file_size - Footer::kEncodedLength,
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Footer::kEncodedLength,
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&footer_input,
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footer_space);
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if (!s.ok()) return s;
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// Check that we actually read the whole footer from the file. It may be
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// that size isn't correct.
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if (footer_input.size() != Footer::kEncodedLength) {
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return Status::InvalidArgument("file is too short to be an sstable");
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}
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return footer->DecodeFrom(&footer_input);
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}
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Status ReadBlockContents(RandomAccessFile* file,
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const ReadOptions& options,
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const BlockHandle& handle,
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BlockContents* result,
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Env* env,
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bool do_uncompress) {
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result->data = Slice();
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result->cachable = false;
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result->heap_allocated = false;
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// Read the block contents as well as the type/crc footer.
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// See table_builder.cc for the code that built this structure.
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size_t n = static_cast<size_t>(handle.size());
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char* buf = new char[n + kBlockTrailerSize];
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Slice contents;
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StopWatchNano timer(env);
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StartPerfTimer(&timer);
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Status s = file->Read(handle.offset(), n + kBlockTrailerSize, &contents, buf);
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BumpPerfCount(&perf_context.block_read_count);
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BumpPerfCount(&perf_context.block_read_byte, n + kBlockTrailerSize);
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BumpPerfTime(&perf_context.block_read_time, &timer);
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if (!s.ok()) {
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delete[] buf;
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return s;
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}
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if (contents.size() != n + kBlockTrailerSize) {
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delete[] buf;
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return Status::Corruption("truncated block read");
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}
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// Check the crc of the type and the block contents
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const char* data = contents.data(); // Pointer to where Read put the data
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if (options.verify_checksums) {
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const uint32_t crc = crc32c::Unmask(DecodeFixed32(data + n + 1));
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const uint32_t actual = crc32c::Value(data, n + 1);
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if (actual != crc) {
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delete[] buf;
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s = Status::Corruption("block checksum mismatch");
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return s;
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}
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BumpPerfTime(&perf_context.block_checksum_time, &timer);
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}
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// If the caller has requested that the block not be uncompressed
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if (!do_uncompress || data[n] == kNoCompression) {
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if (data != buf) {
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// File implementation gave us pointer to some other data.
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// Use it directly under the assumption that it will be live
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// while the file is open.
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delete[] buf;
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result->data = Slice(data, n);
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result->heap_allocated = false;
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result->cachable = false; // Do not double-cache
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} else {
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result->data = Slice(buf, n);
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result->heap_allocated = true;
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result->cachable = true;
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}
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result->compression_type = (rocksdb::CompressionType)data[n];
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s = Status::OK();
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} else {
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s = UncompressBlockContents(data, n, result);
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delete[] buf;
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}
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BumpPerfTime(&perf_context.block_decompress_time, &timer);
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return s;
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}
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//
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// The 'data' points to the raw block contents that was read in from file.
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// This method allocates a new heap buffer and the raw block
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// contents are uncompresed into this buffer. This
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// buffer is returned via 'result' and it is upto the caller to
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// free this buffer.
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Status UncompressBlockContents(const char* data, size_t n,
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BlockContents* result) {
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char* ubuf = nullptr;
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int decompress_size = 0;
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assert(data[n] != kNoCompression);
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switch (data[n]) {
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case kSnappyCompression: {
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size_t ulength = 0;
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static char snappy_corrupt_msg[] =
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"Snappy not supported or corrupted Snappy compressed block contents";
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if (!port::Snappy_GetUncompressedLength(data, n, &ulength)) {
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return Status::Corruption(snappy_corrupt_msg);
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}
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ubuf = new char[ulength];
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if (!port::Snappy_Uncompress(data, n, ubuf)) {
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delete[] ubuf;
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return Status::Corruption(snappy_corrupt_msg);
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}
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result->data = Slice(ubuf, ulength);
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result->heap_allocated = true;
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result->cachable = true;
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break;
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}
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case kZlibCompression:
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ubuf = port::Zlib_Uncompress(data, n, &decompress_size);
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static char zlib_corrupt_msg[] =
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"Zlib not supported or corrupted Zlib compressed block contents";
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if (!ubuf) {
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return Status::Corruption(zlib_corrupt_msg);
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}
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result->data = Slice(ubuf, decompress_size);
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result->heap_allocated = true;
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result->cachable = true;
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break;
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case kBZip2Compression:
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ubuf = port::BZip2_Uncompress(data, n, &decompress_size);
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static char bzip2_corrupt_msg[] =
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"Bzip2 not supported or corrupted Bzip2 compressed block contents";
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if (!ubuf) {
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return Status::Corruption(bzip2_corrupt_msg);
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}
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result->data = Slice(ubuf, decompress_size);
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result->heap_allocated = true;
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result->cachable = true;
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break;
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default:
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return Status::Corruption("bad block type");
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}
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result->compression_type = kNoCompression; // not compressed any more
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return Status::OK();
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}
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} // namespace rocksdb
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