mirror of
https://github.com/facebook/rocksdb.git
synced 2024-11-26 16:30:56 +00:00
76 lines
2.2 KiB
C
76 lines
2.2 KiB
C
|
// 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.
|
||
|
|
|
||
|
|
#ifndef STORAGE_LEVELDB_DB_LOG_READER_H_
|
||
|
|
#define STORAGE_LEVELDB_DB_LOG_READER_H_
|
||
|
|
|
||
|
|
#include "db/log_format.h"
|
||
|
|
#include "include/slice.h"
|
||
|
|
#include "include/status.h"
|
||
|
|
|
||
|
|
namespace leveldb {
|
||
|
|
|
||
|
|
class SequentialFile;
|
||
|
|
|
||
|
|
namespace log {
|
||
|
|
|
||
|
|
class Reader {
|
||
|
|
public:
|
||
|
|
// Interface for reporting errors.
|
||
|
|
class Reporter {
|
||
|
|
public:
|
||
|
|
virtual ~Reporter();
|
||
|
|
|
||
|
|
// Some corruption was detected. "size" is the approximate number
|
||
|
|
// of bytes dropped due to the corruption.
|
||
|
|
virtual void Corruption(size_t bytes, const Status& status) = 0;
|
||
|
|
};
|
||
|
|
|
||
|
|
// Create a reader that will return log records from "*file".
|
||
|
|
// "*file" must remain live while this Reader is in use.
|
||
|
|
//
|
||
|
|
// If "reporter" is non-NULL, it is notified whenever some data is
|
||
|
|
// dropped due to a detected corruption. "*reporter" must remain
|
||
|
|
// live while this Reader is in use.
|
||
|
|
//
|
||
|
|
// If "checksum" is true, verify checksums if available.
|
||
|
|
Reader(SequentialFile* file, Reporter* reporter, bool checksum);
|
||
|
|
|
||
|
|
~Reader();
|
||
|
|
|
||
|
|
// Read the next record into *record. Returns true if read
|
||
|
|
// successfully, false if we hit end of the input. May use
|
||
|
|
// "*scratch" as temporary storage. The contents filled in *record
|
||
|
|
// will only be valid until the next mutating operation on this
|
||
|
|
// reader or the next mutation to *scratch.
|
||
|
|
bool ReadRecord(Slice* record, std::string* scratch);
|
||
|
|
|
||
|
|
private:
|
||
|
|
SequentialFile* const file_;
|
||
|
|
Reporter* const reporter_;
|
||
|
|
bool const checksum_;
|
||
|
|
char* const backing_store_;
|
||
|
|
Slice buffer_;
|
||
|
|
bool eof_; // Last Read() indicated EOF by returning < kBlockSize
|
||
|
|
|
||
|
|
// Extend record types with the following special values
|
||
|
|
enum {
|
||
|
|
kEof = kMaxRecordType + 1,
|
||
|
|
kBadRecord = kMaxRecordType + 2
|
||
|
|
};
|
||
|
|
|
||
|
|
// Return type, or one of the preceding special values
|
||
|
|
unsigned int ReadPhysicalRecord(Slice* result);
|
||
|
|
void ReportDrop(size_t bytes, const char* reason);
|
||
|
|
|
||
|
|
// No copying allowed
|
||
|
|
Reader(const Reader&);
|
||
|
|
void operator=(const Reader&);
|
||
|
|
};
|
||
|
|
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif // STORAGE_LEVELDB_DB_LOG_READER_H_
|