作者: 谢瑞阳 10225101483 徐翔宇 10225101535
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// Copyright (c) 2012 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 "leveldb/dumpfile.h"
#include <cstdio>
#include "db/dbformat.h"
#include "db/filename.h"
#include "db/log_reader.h"
#include "db/version_edit.h"
#include "db/write_batch_internal.h"
#include "leveldb/env.h"
#include "leveldb/iterator.h"
#include "leveldb/options.h"
#include "leveldb/status.h"
#include "leveldb/table.h"
#include "leveldb/write_batch.h"
#include "util/logging.h"
namespace leveldb {
namespace {
bool GuessType(const std::string& fname, FileType* type) {
size_t pos = fname.rfind('/');
std::string basename;
if (pos == std::string::npos) {
basename = fname;
} else {
basename = std::string(fname.data() + pos + 1, fname.size() - pos - 1);
}
uint64_t ignored;
return ParseFileName(basename, &ignored, type);
}
// Notified when log reader encounters corruption.
class CorruptionReporter : public log::Reader::Reporter {
public:
void Corruption(size_t bytes, const Status& status) override {
std::string r = "corruption: ";
AppendNumberTo(&r, bytes);
r += " bytes; ";
r += status.ToString();
r.push_back('\n');
dst_->Append(r);
}
WritableFile* dst_;
};
// Print contents of a log file. (*func)() is called on every record.
Status PrintLogContents(Env* env, const std::string& fname,
void (*func)(uint64_t, Slice, WritableFile*),
WritableFile* dst) {
SequentialFile* file;
Status s = env->NewSequentialFile(fname, &file);
if (!s.ok()) {
return s;
}
CorruptionReporter reporter;
reporter.dst_ = dst;
log::Reader reader(file, &reporter, true, 0);
Slice record;
std::string scratch;
while (reader.ReadRecord(&record, &scratch)) {
(*func)(reader.LastRecordOffset(), record, dst);
}
delete file;
return Status::OK();
}
// Called on every item found in a WriteBatch.
class WriteBatchItemPrinter : public WriteBatch::Handler {
public:
void Put(const Slice& key, const Slice& value) override {
std::string r = " put '";
AppendEscapedStringTo(&r, key);
r += "' '";
AppendEscapedStringTo(&r, value);
r += "'\n";
dst_->Append(r);
}
void Delete(const Slice& key) override {
std::string r = " del '";
AppendEscapedStringTo(&r, key);
r += "'\n";
dst_->Append(r);
}
WritableFile* dst_;
};
// Called on every log record (each one of which is a WriteBatch)
// found in a kLogFile.
static void WriteBatchPrinter(uint64_t pos, Slice record, WritableFile* dst) {
std::string r = "--- offset ";
AppendNumberTo(&r, pos);
r += "; ";
if (record.size() < 12) {
r += "log record length ";
AppendNumberTo(&r, record.size());
r += " is too small\n";
dst->Append(r);
return;
}
WriteBatch batch;
WriteBatchInternal::SetContents(&batch, record);
r += "sequence ";
AppendNumberTo(&r, WriteBatchInternal::Sequence(&batch));
r.push_back('\n');
dst->Append(r);
WriteBatchItemPrinter batch_item_printer;
batch_item_printer.dst_ = dst;
Status s = batch.Iterate(&batch_item_printer);
if (!s.ok()) {
dst->Append(" error: " + s.ToString() + "\n");
}
}
Status DumpLog(Env* env, const std::string& fname, WritableFile* dst) {
return PrintLogContents(env, fname, WriteBatchPrinter, dst);
}
// Called on every log record (each one of which is a WriteBatch)
// found in a kDescriptorFile.
static void VersionEditPrinter(uint64_t pos, Slice record, WritableFile* dst) {
std::string r = "--- offset ";
AppendNumberTo(&r, pos);
r += "; ";
VersionEdit edit;
Status s = edit.DecodeFrom(record);
if (!s.ok()) {
r += s.ToString();
r.push_back('\n');
} else {
r += edit.DebugString();
}
dst->Append(r);
}
Status DumpDescriptor(Env* env, const std::string& fname, WritableFile* dst) {
return PrintLogContents(env, fname, VersionEditPrinter, dst);
}
Status DumpTable(Env* env, const std::string& fname, WritableFile* dst) {
uint64_t file_size;
RandomAccessFile* file = nullptr;
Table* table = nullptr;
Status s = env->GetFileSize(fname, &file_size);
if (s.ok()) {
s = env->NewRandomAccessFile(fname, &file);
}
if (s.ok()) {
// We use the default comparator, which may or may not match the
// comparator used in this database. However this should not cause
// problems since we only use Table operations that do not require
// any comparisons. In particular, we do not call Seek or Prev.
s = Table::Open(Options(), file, file_size, &table);
}
if (!s.ok()) {
delete table;
delete file;
return s;
}
ReadOptions ro;
ro.fill_cache = false;
Iterator* iter = table->NewIterator(ro);
std::string r;
for (iter->SeekToFirst(); iter->Valid(); iter->Next()) {
r.clear();
ParsedInternalKey key;
if (!ParseInternalKey(iter->key(), &key)) {
r = "badkey '";
AppendEscapedStringTo(&r, iter->key());
r += "' => '";
AppendEscapedStringTo(&r, iter->value());
r += "'\n";
dst->Append(r);
} else {
r = "'";
AppendEscapedStringTo(&r, key.user_key);
r += "' @ ";
AppendNumberTo(&r, key.sequence);
r += " : ";
if (key.type == kTypeDeletion) {
r += "del";
} else if (key.type == kTypeValue) {
r += "val";
} else {
AppendNumberTo(&r, key.type);
}
r += " => '";
AppendEscapedStringTo(&r, iter->value());
r += "'\n";
dst->Append(r);
}
}
s = iter->status();
if (!s.ok()) {
dst->Append("iterator error: " + s.ToString() + "\n");
}
delete iter;
delete table;
delete file;
return Status::OK();
}
} // namespace
Status DumpFile(Env* env, const std::string& fname, WritableFile* dst) {
FileType ftype;
if (!GuessType(fname, &ftype)) {
return Status::InvalidArgument(fname + ": unknown file type");
}
switch (ftype) {
case kLogFile:
return DumpLog(env, fname, dst);
case kDescriptorFile:
return DumpDescriptor(env, fname, dst);
case kTableFile:
return DumpTable(env, fname, dst);
default:
break;
}
return Status::InvalidArgument(fname + ": not a dump-able file type");
}
} // namespace leveldb