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mongodb/db/client.h
2010-12-17 00:22:20 -05:00

259 lines
8.3 KiB
C++

// client.h
/**
* 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/>.
*/
/* 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.
*/
#pragma once
#include "../pch.h"
#include "security.h"
#include "namespace-inl.h"
#include "lasterror.h"
#include "stats/top.h"
namespace mongo {
extern class ReplSet *theReplSet;
class AuthenticationInfo;
class Database;
class CurOp;
class Command;
class Client;
class MessagingPort;
extern boost::thread_specific_ptr<Client> currentClient;
class Client : boost::noncopyable {
public:
static Client *syncThread;
void iAmSyncThread() {
wassert( syncThread == 0 );
syncThread = this;
}
bool isSyncThread() const { return this == syncThread; } // true if this client is the replication secondary pull thread
static mongo::mutex clientsMutex;
static set<Client*> clients; // always be in clientsMutex when manipulating this
static int recommendedYieldMicros( int * writers = 0 , int * readers = 0 );
static int getActiveClientCount( int& writers , int& readers );
/* set _god=true temporarily, safely */
class GodScope {
bool _prev;
public:
GodScope();
~GodScope();
};
/* 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{
Client * _client;
Context * _oldContext;
string _path;
mongolock * _lock;
bool _justCreated;
string _ns;
Database * _db;
/**
* at this point _client, _oldContext and _ns have to be set
* _db should not have been touched
* this will set _db and create if needed
* will also set _client->_context to this
*/
void _finishInit( bool doauth=true);
void _auth( int lockState = dbMutex.getState() );
public:
Context(const string& ns, string path=dbpath, mongolock * lock = 0 , bool doauth=true )
: _client( currentClient.get() ) , _oldContext( _client->_context ) ,
_path( path ) , _lock( lock ) ,
_ns( ns ), _db(0){
_finishInit( doauth );
}
/* this version saves the context but doesn't yet set the new one: */
Context()
: _client( currentClient.get() ) , _oldContext( _client->_context ),
_path( dbpath ) , _lock(0) , _justCreated(false), _db(0){
_client->_context = this;
clear();
}
/**
* if you are doing this after allowing a write there could be a race condition
* if someone closes that db. this checks that the DB is still valid
*/
Context( string ns , Database * db, bool doauth=true );
~Context();
Client* getClient() const { return _client; }
Database* db() const { return _db; }
const char * ns() const { return _ns.c_str(); }
bool justCreated() const { return _justCreated; }
bool equals( const string& ns , const string& path=dbpath ) const {
return _ns == ns && _path == path;
}
bool inDB( const string& db , const string& path=dbpath ) const {
if ( _path != path )
return false;
if ( db == _ns )
return true;
string::size_type idx = _ns.find( db );
if ( idx != 0 )
return false;
return _ns[db.size()] == '.';
}
void clear(){
_ns = "";
_db = 0;
}
/**
* call before unlocking, so clear any non-thread safe state
*/
void unlocked(){
_db = 0;
}
/**
* call after going back into the lock, will re-establish non-thread safe stuff
*/
void relocked(){
_finishInit();
}
friend class CurOp;
}; // class Client::Context
private:
CurOp * _curOp;
Context * _context;
bool _shutdown;
const char *_desc;
bool _god;
AuthenticationInfo _ai;
ReplTime _lastOp;
BSONObj _handshake;
BSONObj _remoteId;
public:
MessagingPort * const _mp;
Client(const char *desc, MessagingPort *p = 0);
~Client();
string clientAddress(bool includePort=false) const;
AuthenticationInfo * getAuthenticationInfo(){ return &_ai; }
bool isAdmin() { return _ai.isAuthorized( "admin" ); }
CurOp* curop() { return _curOp; }
Context* getContext(){ return _context; }
Database* database() { return _context ? _context->db() : 0; }
const char *ns() const { return _context->ns(); }
const char *desc() const { return _desc; }
void setLastOp( ReplTime op ) { _lastOp = op; }
ReplTime getLastOp() const { return _lastOp; }
/* report what the last operation was. used by getlasterror */
void appendLastOp( BSONObjBuilder& b ) {
if( theReplSet ) {
b.append("lastOp" , (long long) _lastOp);
}
else {
OpTime lo(_lastOp);
if ( ! lo.isNull() )
b.appendTimestamp( "lastOp" , lo.asDate() );
}
}
/* each thread which does db operations has a Client object in TLS.
call this when your thread starts.
*/
static Client& initThread(const char *desc, MessagingPort *mp = 0);
/*
this has to be called as the client goes away, but before thread termination
@return true if anything was done
*/
bool shutdown();
bool isGod() const { return _god; } /* this is for map/reduce writes */
string toString() const;
void gotHandshake( const BSONObj& o );
BSONObj getRemoteID() const { return _remoteId; }
BSONObj getHandshake() const { return _handshake; }
friend class CurOp;
};
/** get the Client object for this thread. */
inline Client& cc() {
Client * c = currentClient.get();
assert( c );
return *c;
}
inline Client::GodScope::GodScope(){
_prev = cc()._god;
cc()._god = true;
}
inline Client::GodScope::~GodScope() { cc()._god = _prev; }
/* this unlocks, does NOT upgrade. that works for our current usage */
inline void mongolock::releaseAndWriteLock() {
if( !_writelock ) {
#if BOOST_VERSION >= 103500
int s = dbMutex.getState();
if( s != -1 ) {
log() << "error: releaseAndWriteLock() s == " << s << endl;
msgasserted( 12600, "releaseAndWriteLock: unlock_shared failed, probably recursive" );
}
#endif
_writelock = true;
dbMutex.unlock_shared();
dbMutex.lock();
if ( cc().getContext() )
cc().getContext()->unlocked();
}
}
string sayClientState();
inline bool haveClient() { return currentClient.get() > 0; }
};