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Diffstat (limited to 'src/leveldb/db/log_reader.cc')
-rw-r--r--src/leveldb/db/log_reader.cc259
1 files changed, 0 insertions, 259 deletions
diff --git a/src/leveldb/db/log_reader.cc b/src/leveldb/db/log_reader.cc
deleted file mode 100644
index b35f115aad..0000000000
--- a/src/leveldb/db/log_reader.cc
+++ /dev/null
@@ -1,259 +0,0 @@
-// 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 "db/log_reader.h"
-
-#include <stdio.h>
-#include "leveldb/env.h"
-#include "util/coding.h"
-#include "util/crc32c.h"
-
-namespace leveldb {
-namespace log {
-
-Reader::Reporter::~Reporter() {
-}
-
-Reader::Reader(SequentialFile* file, Reporter* reporter, bool checksum,
- uint64_t initial_offset)
- : file_(file),
- reporter_(reporter),
- checksum_(checksum),
- backing_store_(new char[kBlockSize]),
- buffer_(),
- eof_(false),
- last_record_offset_(0),
- end_of_buffer_offset_(0),
- initial_offset_(initial_offset) {
-}
-
-Reader::~Reader() {
- delete[] backing_store_;
-}
-
-bool Reader::SkipToInitialBlock() {
- size_t offset_in_block = initial_offset_ % kBlockSize;
- uint64_t block_start_location = initial_offset_ - offset_in_block;
-
- // Don't search a block if we'd be in the trailer
- if (offset_in_block > kBlockSize - 6) {
- offset_in_block = 0;
- block_start_location += kBlockSize;
- }
-
- end_of_buffer_offset_ = block_start_location;
-
- // Skip to start of first block that can contain the initial record
- if (block_start_location > 0) {
- Status skip_status = file_->Skip(block_start_location);
- if (!skip_status.ok()) {
- ReportDrop(block_start_location, skip_status);
- return false;
- }
- }
-
- return true;
-}
-
-bool Reader::ReadRecord(Slice* record, std::string* scratch) {
- if (last_record_offset_ < initial_offset_) {
- if (!SkipToInitialBlock()) {
- return false;
- }
- }
-
- scratch->clear();
- record->clear();
- bool in_fragmented_record = false;
- // Record offset of the logical record that we're reading
- // 0 is a dummy value to make compilers happy
- uint64_t prospective_record_offset = 0;
-
- Slice fragment;
- while (true) {
- uint64_t physical_record_offset = end_of_buffer_offset_ - buffer_.size();
- const unsigned int record_type = ReadPhysicalRecord(&fragment);
- switch (record_type) {
- case kFullType:
- if (in_fragmented_record) {
- // Handle bug in earlier versions of log::Writer where
- // it could emit an empty kFirstType record at the tail end
- // of a block followed by a kFullType or kFirstType record
- // at the beginning of the next block.
- if (scratch->empty()) {
- in_fragmented_record = false;
- } else {
- ReportCorruption(scratch->size(), "partial record without end(1)");
- }
- }
- prospective_record_offset = physical_record_offset;
- scratch->clear();
- *record = fragment;
- last_record_offset_ = prospective_record_offset;
- return true;
-
- case kFirstType:
- if (in_fragmented_record) {
- // Handle bug in earlier versions of log::Writer where
- // it could emit an empty kFirstType record at the tail end
- // of a block followed by a kFullType or kFirstType record
- // at the beginning of the next block.
- if (scratch->empty()) {
- in_fragmented_record = false;
- } else {
- ReportCorruption(scratch->size(), "partial record without end(2)");
- }
- }
- prospective_record_offset = physical_record_offset;
- scratch->assign(fragment.data(), fragment.size());
- in_fragmented_record = true;
- break;
-
- case kMiddleType:
- if (!in_fragmented_record) {
- ReportCorruption(fragment.size(),
- "missing start of fragmented record(1)");
- } else {
- scratch->append(fragment.data(), fragment.size());
- }
- break;
-
- case kLastType:
- if (!in_fragmented_record) {
- ReportCorruption(fragment.size(),
- "missing start of fragmented record(2)");
- } else {
- scratch->append(fragment.data(), fragment.size());
- *record = Slice(*scratch);
- last_record_offset_ = prospective_record_offset;
- return true;
- }
- break;
-
- case kEof:
- if (in_fragmented_record) {
- ReportCorruption(scratch->size(), "partial record without end(3)");
- scratch->clear();
- }
- return false;
-
- case kBadRecord:
- if (in_fragmented_record) {
- ReportCorruption(scratch->size(), "error in middle of record");
- in_fragmented_record = false;
- scratch->clear();
- }
- break;
-
- default: {
- char buf[40];
- snprintf(buf, sizeof(buf), "unknown record type %u", record_type);
- ReportCorruption(
- (fragment.size() + (in_fragmented_record ? scratch->size() : 0)),
- buf);
- in_fragmented_record = false;
- scratch->clear();
- break;
- }
- }
- }
- return false;
-}
-
-uint64_t Reader::LastRecordOffset() {
- return last_record_offset_;
-}
-
-void Reader::ReportCorruption(size_t bytes, const char* reason) {
- ReportDrop(bytes, Status::Corruption(reason));
-}
-
-void Reader::ReportDrop(size_t bytes, const Status& reason) {
- if (reporter_ != NULL &&
- end_of_buffer_offset_ - buffer_.size() - bytes >= initial_offset_) {
- reporter_->Corruption(bytes, reason);
- }
-}
-
-unsigned int Reader::ReadPhysicalRecord(Slice* result) {
- while (true) {
- if (buffer_.size() < kHeaderSize) {
- if (!eof_) {
- // Last read was a full read, so this is a trailer to skip
- buffer_.clear();
- Status status = file_->Read(kBlockSize, &buffer_, backing_store_);
- end_of_buffer_offset_ += buffer_.size();
- if (!status.ok()) {
- buffer_.clear();
- ReportDrop(kBlockSize, status);
- eof_ = true;
- return kEof;
- } else if (buffer_.size() < kBlockSize) {
- eof_ = true;
- }
- continue;
- } else if (buffer_.size() == 0) {
- // End of file
- return kEof;
- } else {
- size_t drop_size = buffer_.size();
- buffer_.clear();
- ReportCorruption(drop_size, "truncated record at end of file");
- return kEof;
- }
- }
-
- // Parse the header
- const char* header = buffer_.data();
- const uint32_t a = static_cast<uint32_t>(header[4]) & 0xff;
- const uint32_t b = static_cast<uint32_t>(header[5]) & 0xff;
- const unsigned int type = header[6];
- const uint32_t length = a | (b << 8);
- if (kHeaderSize + length > buffer_.size()) {
- size_t drop_size = buffer_.size();
- buffer_.clear();
- ReportCorruption(drop_size, "bad record length");
- return kBadRecord;
- }
-
- if (type == kZeroType && length == 0) {
- // Skip zero length record without reporting any drops since
- // such records are produced by the mmap based writing code in
- // env_posix.cc that preallocates file regions.
- buffer_.clear();
- return kBadRecord;
- }
-
- // Check crc
- if (checksum_) {
- uint32_t expected_crc = crc32c::Unmask(DecodeFixed32(header));
- uint32_t actual_crc = crc32c::Value(header + 6, 1 + length);
- if (actual_crc != expected_crc) {
- // Drop the rest of the buffer since "length" itself may have
- // been corrupted and if we trust it, we could find some
- // fragment of a real log record that just happens to look
- // like a valid log record.
- size_t drop_size = buffer_.size();
- buffer_.clear();
- ReportCorruption(drop_size, "checksum mismatch");
- return kBadRecord;
- }
- }
-
- buffer_.remove_prefix(kHeaderSize + length);
-
- // Skip physical record that started before initial_offset_
- if (end_of_buffer_offset_ - buffer_.size() - kHeaderSize - length <
- initial_offset_) {
- result->clear();
- return kBadRecord;
- }
-
- *result = Slice(header + kHeaderSize, length);
- return type;
- }
-}
-
-} // namespace log
-} // namespace leveldb
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