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112 lines
3.9 KiB
C++
112 lines
3.9 KiB
C++
// @file durop.h class DurOp and descendants
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/**
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* Copyright (C) 2010 10gen Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License, version 3,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#pragma once
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#include "dur_journalformat.h"
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#include "../util/bufreader.h"
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#include "../util/paths.h"
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namespace mongo {
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class AlignedBuilder;
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namespace dur {
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const unsigned Alignment = 8192;
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/** DurOp - Operations we journal that aren't just basic writes.
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*
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* Basic writes are logged as JEntry's, and indicated in ram temporarily as struct dur::WriteIntent.
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* We don't make WriteIntent inherit from DurOp to keep it as lean as possible as there will be millions of
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* them (we don't want a vtable for example there).
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*
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* For each op we want to journal, we define a subclass.
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*/
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class DurOp { /* copyable */
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public:
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// @param opcode a sentinel value near max unsigned which uniquely identifies the operation.
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// @see dur::JEntry
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DurOp(unsigned opcode) : _opcode(opcode) { }
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virtual ~DurOp() { }
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/** serialize the op out to a builder which will then be written (presumably) to the journal */
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void serialize(AlignedBuilder& ab);
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/** read a durop from journal file referenced by br.
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@param opcode the opcode which has already been written from the bufreader
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*/
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static shared_ptr<DurOp> read(unsigned opcode, BufReader& br);
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/** replay the operation (during recovery)
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throws
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For now, these are not replayed during the normal WRITETODATAFILES phase, since these
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operations are handled in other parts of the code. At some point this may change.
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*/
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virtual void replay() = 0;
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virtual string toString() = 0;
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/** if the op requires all file to be closed before doing its work, returns true. */
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virtual bool needFilesClosed() { return false; }
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protected:
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/** DurOp will have already written the opcode for you */
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virtual void _serialize(AlignedBuilder& ab) = 0;
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private:
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const unsigned _opcode;
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};
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/** indicates creation of a new file */
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class FileCreatedOp : public DurOp {
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public:
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FileCreatedOp(BufReader& log);
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/** param f filename to create with path */
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FileCreatedOp(string f, unsigned long long l);
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virtual void replay();
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virtual string toString();
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virtual bool needFilesClosed();
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protected:
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virtual void _serialize(AlignedBuilder& ab);
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private:
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RelativePath _p;
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unsigned long long _len; // size of file, not length of name
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};
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/** record drop of a database */
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class DropDbOp : public DurOp {
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public:
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DropDbOp(BufReader& log);
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DropDbOp(string db) :
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DurOp(JEntry::OpCode_DropDb), _db(db) { }
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virtual void replay();
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virtual string toString() { return string("DropDbOp ") + _db; }
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virtual bool needFilesClosed() { return true; }
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protected:
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virtual void _serialize(AlignedBuilder& ab);
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private:
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string _db;
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};
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}
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}
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