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rocksdb/db/transaction_log_iterator_im...

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#include "db/transaction_log_iterator_impl.h"
#include "db/write_batch_internal.h"
#include "db/filename.h"
namespace leveldb {
TransactionLogIteratorImpl::TransactionLogIteratorImpl(
const std::string& dbname,
const Options* options,
const StorageOptions& soptions,
SequenceNumber& seq,
std::unique_ptr<std::vector<LogFile>> files,
SequenceNumber const * const lastFlushedSequence) :
dbname_(dbname),
options_(options),
soptions_(soptions),
startingSequenceNumber_(seq),
files_(std::move(files)),
started_(false),
isValid_(false),
currentFileIndex_(0),
lastFlushedSequence_(lastFlushedSequence) {
assert(files_.get() != nullptr);
assert(lastFlushedSequence_);
reporter_.env = options_->env;
reporter_.info_log = options_->info_log.get();
}
Status TransactionLogIteratorImpl::OpenLogFile(
const LogFile& logFile,
unique_ptr<SequentialFile>* file) {
Env* env = options_->env;
if (logFile.type == kArchivedLogFile) {
std::string fname = ArchivedLogFileName(dbname_, logFile.logNumber);
return env->NewSequentialFile(fname, file, soptions_);
} else {
std::string fname = LogFileName(dbname_, logFile.logNumber);
Status status = env->NewSequentialFile(fname, file, soptions_);
if (!status.ok()) {
// If cannot open file in DB directory.
// Try the archive dir, as it could have moved in the meanwhile.
fname = ArchivedLogFileName(dbname_, logFile.logNumber);
status = env->NewSequentialFile(fname, file, soptions_);
if (!status.ok()) {
return Status::IOError(" Requested file not present in the dir");
}
}
return status;
}
}
BatchResult TransactionLogIteratorImpl::GetBatch() {
assert(isValid_); // cannot call in a non valid state.
BatchResult result;
result.sequence = currentSequence_;
result.writeBatchPtr = std::move(currentBatch_);
return result;
}
Status TransactionLogIteratorImpl::status() {
return currentStatus_;
}
bool TransactionLogIteratorImpl::Valid() {
return started_ && isValid_;
}
void TransactionLogIteratorImpl::Next() {
LogFile currentLogFile = files_.get()->at(currentFileIndex_);
// First seek to the given seqNo. in the current file.
std::string scratch;
Slice record;
if (!started_) {
started_ = true; // this piece only runs onced.
isValid_ = false;
if (startingSequenceNumber_ > *lastFlushedSequence_) {
currentStatus_ = Status::IOError("Looking for a sequence, "
"which is not flushed yet.");
return;
}
Status s = OpenLogReader(currentLogFile);
if (!s.ok()) {
currentStatus_ = s;
isValid_ = false;
return;
}
while (currentLogReader_->ReadRecord(&record, &scratch)) {
if (record.size() < 12) {
reporter_.Corruption(
record.size(), Status::Corruption("log record too small"));
continue;
}
UpdateCurrentWriteBatch(record);
if (currentSequence_ >= startingSequenceNumber_) {
assert(currentSequence_ <= *lastFlushedSequence_);
isValid_ = true;
break;
} else {
isValid_ = false;
}
}
if (isValid_) {
// Done for this iteration
return;
}
}
bool openNextFile = true;
while(openNextFile) {
assert(currentLogReader_);
if (currentSequence_ < *lastFlushedSequence_) {
if (currentLogReader_->IsEOF()) {
currentLogReader_->UnmarkEOF();
}
while (currentLogReader_->ReadRecord(&record, &scratch)) {
if (record.size() < 12) {
reporter_.Corruption(
record.size(), Status::Corruption("log record too small"));
continue;
} else {
UpdateCurrentWriteBatch(record);
openNextFile = false;
break;
}
}
}
if (openNextFile) {
if (currentFileIndex_ < files_.get()->size() - 1) {
++currentFileIndex_;
Status status = OpenLogReader(files_.get()->at(currentFileIndex_));
if (!status.ok()) {
isValid_ = false;
currentStatus_ = status;
return;
}
} else {
isValid_ = false;
openNextFile = false;
if (currentSequence_ == *lastFlushedSequence_) {
currentStatus_ = Status::OK();
} else {
currentStatus_ = Status::IOError(" NO MORE DATA LEFT");
}
}
}
}
}
void TransactionLogIteratorImpl::UpdateCurrentWriteBatch(const Slice& record) {
WriteBatch* batch = new WriteBatch();
WriteBatchInternal::SetContents(batch, record);
currentSequence_ = WriteBatchInternal::Sequence(batch);
currentBatch_.reset(batch);
isValid_ = true;
currentStatus_ = Status::OK();
}
Status TransactionLogIteratorImpl::OpenLogReader(const LogFile& logFile) {
unique_ptr<SequentialFile> file;
Status status = OpenLogFile(logFile, &file);
if (!status.ok()) {
return status;
}
assert(file);
currentLogReader_.reset(
new log::Reader(std::move(file), &reporter_, true, 0)
);
return Status::OK();
}
} // namespace leveldb