147 lines
4.4 KiB
C++
147 lines
4.4 KiB
C++
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#include "db/transaction_log_iterator_impl.h"
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#include "db/write_batch_internal.h"
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#include "db/filename.h"
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namespace leveldb {
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TransactionLogIteratorImpl::TransactionLogIteratorImpl(
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const std::string& dbname,
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const Options* options,
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SequenceNumber& seq,
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std::vector<LogFile>* files) :
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dbname_(dbname),
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options_(options),
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sequenceNumber_(seq),
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files_(files),
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started_(false),
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isValid_(true),
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currentFileIndex_(0),
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currentLogReader_(NULL) {
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assert( files_ != NULL);
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}
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LogReporter
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TransactionLogIteratorImpl::NewLogReporter(const uint64_t logNumber) {
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LogReporter reporter;
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reporter.env = options_->env;
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reporter.info_log = options_->info_log;
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reporter.log_number = logNumber;
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return reporter;
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}
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Status TransactionLogIteratorImpl::OpenLogFile(const LogFile& logFile,
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SequentialFile** file) {
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Env* env = options_->env;
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if (logFile.type == kArchivedLogFile) {
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std::string fname = ArchivedLogFileName(dbname_, logFile.logNumber);
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return env->NewSequentialFile(fname, file);
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} else {
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std::string fname = LogFileName(dbname_, logFile.logNumber);
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Status status = env->NewSequentialFile(fname, file);
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if (!status.ok()) {
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// If cannot open file in DB directory.
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// Try the archive dir, as it could have moved in the meanwhile.
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fname = ArchivedLogFileName(dbname_, logFile.logNumber);
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status = env->NewSequentialFile(fname, file);
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if (!status.ok()) {
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// TODO stringprintf
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return Status::IOError(" Requested file not present in the dir");
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}
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}
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return status;
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}
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}
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void TransactionLogIteratorImpl::GetBatch(WriteBatch* batch) {
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assert(isValid_); // cannot call in a non valid state.
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WriteBatchInternal::SetContents(batch, currentRecord_);
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}
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Status TransactionLogIteratorImpl::status() {
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return currentStatus_;
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}
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bool TransactionLogIteratorImpl::Valid() {
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return started_ && isValid_;
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}
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void TransactionLogIteratorImpl::Next() {
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// First seek to the given seqNo. in the current file.
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LogFile currentLogFile = files_->at(currentFileIndex_);
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LogReporter reporter = NewLogReporter(currentLogFile.logNumber);
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std::string scratch;
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Slice record;
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if (!started_) {
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SequentialFile* file = NULL;
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Status status = OpenLogFile(currentLogFile, &file);
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if (!status.ok()) {
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isValid_ = false;
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currentStatus_ = status;
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return;
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}
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assert(file != NULL);
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WriteBatch batch;
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log::Reader* reader = new log::Reader(file, &reporter, true, 0);
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assert(reader != NULL);
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while (reader->ReadRecord(&record, &scratch)) {
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if (record.size() < 12) {
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reporter.Corruption(
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record.size(), Status::Corruption("log record too small"));
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continue;
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}
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WriteBatchInternal::SetContents(&batch, record);
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SequenceNumber currentNum = WriteBatchInternal::Sequence(&batch);
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if (currentNum >= sequenceNumber_) {
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isValid_ = true;
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currentRecord_ = record;
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currentLogReader_ = reader;
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break;
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}
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}
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if (!isValid_) {
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// TODO read the entire first file. and did not find the seq number.
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// Error out.
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currentStatus_ =
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Status::NotFound("Did not find the Seq no. in first file");
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}
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started_ = true;
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} else {
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LOOK_NEXT_FILE:
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assert(currentLogReader_ != NULL);
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bool openNextFile = true;
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while (currentLogReader_->ReadRecord(&record, &scratch)) {
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if (record.size() < 12) {
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reporter.Corruption(
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record.size(), Status::Corruption("log record too small"));
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continue;
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} else {
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currentRecord_ = record;
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openNextFile = false;
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break;
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}
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}
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if (openNextFile) {
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if (currentFileIndex_ < files_->size() - 1) {
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++currentFileIndex_;
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delete currentLogReader_;
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SequentialFile *file;
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Status status = OpenLogFile(files_->at(currentFileIndex_), &file);
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if (!status.ok()) {
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isValid_ = false;
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currentStatus_ = status;
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return;
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}
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currentLogReader_ = new log::Reader(file, &reporter, true, 0);
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goto LOOK_NEXT_FILE;
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} else {
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// LOOKED AT FILES. WE ARE DONE HERE.
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isValid_ = false;
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currentStatus_ = Status::IOError(" NO MORE DATA LEFT");
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}
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}
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}
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}
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} // namespace leveldb
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