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/* @file db/client.h
"Client" represents a connection to the database (the server-side) and corresponds
to an open socket (or logical connection if pooling on sockets) from a client.
todo: switch to asio...this will fit nicely with that.
*/
/**
* Copyright (C) 2008 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include "mongo/pch.h"
#include "mongo/db/client_basic.h"
#include "mongo/db/d_concurrency.h"
#include "mongo/db/lasterror.h"
#include "mongo/db/lockstate.h"
#include "mongo/db/repl/rs.h"
#include "mongo/db/stats/top.h"
#include "mongo/db/storage_options.h"
#include "mongo/util/concurrency/rwlock.h"
#include "mongo/util/concurrency/threadlocal.h"
#include "mongo/util/paths.h"
namespace mongo {
class AuthenticationInfo;
class Database;
class CurOp;
class Command;
class Client;
class AbstractMessagingPort;
class LockCollectionForReading;
TSP_DECLARE(Client, currentClient)
typedef long long ConnectionId;
/** the database's concept of an outside "client" */
class Client : public ClientBasic {
public:
// always be in clientsMutex when manipulating this. killop stuff uses these.
static std::set<Client*>& clients;
static mongo::mutex& clientsMutex;
static int getActiveClientCount( int& writers , int& readers );
class Context;
~Client();
static int recommendedYieldMicros( int * writers = 0 , int * readers = 0,
bool needExact = false );
/** each thread which does db operations has a Client object in TLS.
* call this when your thread starts.
*/
static Client& initThread(const char *desc, AbstractMessagingPort *mp = 0);
static void initThreadIfNotAlready(const char *desc) {
if( currentClient.get() )
return;
initThread(desc);
}
/** this has to be called as the client goes away, but before thread termination
* @return true if anything was done
*/
bool shutdown();
std::string clientAddress(bool includePort=false) const;
CurOp* curop() const { return _curOp; }
Context* getContext() const { return _context; }
const StringData desc() const { return _desc; }
void setLastOp( OpTime op ) { _lastOp = op; }
OpTime getLastOp() const { return _lastOp; }
/* report what the last operation was. used by getlasterror */
void appendLastOp( BSONObjBuilder& b ) const;
bool isGod() const { return _god; } /* this is for map/reduce writes */
bool setGod(bool newVal) { const bool prev = _god; _god = newVal; return prev; }
std::string toString() const;
bool gotHandshake( const BSONObj& o );
BSONObj getRemoteID() const { return _remoteId; }
BSONObj getHandshake() const { return _handshake; }
ConnectionId getConnectionId() const { return _connectionId; }
// XXX(hk): this is per-thread mmapv1 recovery unit stuff, move into that
// impl of recovery unit
void writeHappened() { _hasWrittenSinceCheckpoint = true; }
bool hasWrittenSinceCheckpoint() const { return _hasWrittenSinceCheckpoint; }
void checkpointHappened() { _hasWrittenSinceCheckpoint = false; }
// XXX: this is really a method in the recovery unit iface to reset any state
void newTopLevelRequest() {
_hasWrittenSinceCheckpoint = false;
}
LockState& lockState() { return _ls; }
private:
Client(const std::string& desc, AbstractMessagingPort *p = 0);
friend class CurOp;
ConnectionId _connectionId; // > 0 for things "conn", 0 otherwise
std::string _threadId; // "" on non support systems
CurOp * _curOp;
Context * _context;
bool _shutdown; // to track if Client::shutdown() gets called
std::string _desc;
bool _god;
OpTime _lastOp;
BSONObj _handshake;
BSONObj _remoteId;
bool _hasWrittenSinceCheckpoint;
LockState _ls;
public:
/** "read lock, and set my context, all in one operation"
* This handles (if not recursively locked) opening an unopened database.
*/
class ReadContext : boost::noncopyable {
public:
ReadContext(const std::string& ns,
const std::string& path=storageGlobalParams.dbpath,
bool doVersion = true);
Context& ctx() { return *c.get(); }
private:
scoped_ptr<Lock::DBRead> lk;
scoped_ptr<Context> c;
};
/* Set database we want to use, then, restores when we finish (are out of scope)
Note this is also helpful if an exception happens as the state if fixed up.
*/
class Context : boost::noncopyable {
public:
/** this is probably what you want */
Context(const std::string& ns, const std::string& path=storageGlobalParams.dbpath,
bool doVersion = true);
/** note: this does not call finishInit -- i.e., does not call
shardVersionOk() for example.
see also: reset().
*/
Context(const std::string& ns , Database * db);
// used by ReadContext
Context(const std::string& path, const std::string& ns, Database *db, bool doVersion = true);
~Context();
Client* getClient() const { return _client; }
Database* db() const { return _db; }
const char * ns() const { return _ns.c_str(); }
bool equals(const std::string& ns, const std::string& path=storageGlobalParams.dbpath) const {
return _ns == ns && _path == path;
}
/** @return if the db was created by this Context */
bool justCreated() const { return _justCreated; }
/** @return true iff the current Context is using db/path */
bool inDB(const std::string& db, const std::string& path=storageGlobalParams.dbpath) const;
void _clear() { // this is sort of an "early destruct" indication, _ns can never be uncleared
const_cast<std::string&>(_ns).clear();
_db = 0;
}
/** call before unlocking, so clear any non-thread safe state
* _db gets restored on the relock
*/
void unlocked() { _db = 0; }
/** call after going back into the lock, will re-establish non-thread safe stuff */
void relocked() { _finishInit(); }
private:
friend class CurOp;
void _finishInit();
void checkNotStale() const;
void checkNsAccess( bool doauth );
void checkNsAccess( bool doauth, int lockState );
Client * const _client;
Context * const _oldContext;
const std::string _path;
bool _justCreated;
bool _doVersion;
const std::string _ns;
Database * _db;
Timer _timer;
}; // class Client::Context
class WriteContext : boost::noncopyable {
public:
WriteContext(const std::string& ns,
const std::string& path=storageGlobalParams.dbpath,
bool doVersion = true);
Context& ctx() { return _c; }
private:
Lock::DBWrite _lk;
Context _c;
};
}; // class Client
/** get the Client object for this thread. */
inline Client& cc() {
Client * c = currentClient.get();
verify( c );
return *c;
}
inline bool haveClient() { return currentClient.get() != NULL; }
};
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