C++ client::Context类代码示例

 const char *ourgetns() {
     Client *c = currentClient.get();
     if ( ! c )
         return "";
     Client::Context* cc = c->getContext();
     return cc ? cc->ns() : "";
 }

    /* db - database name
       path - db directory
    */
    /*static*/ void Database::closeDatabase( const char *db, const string& path ) {
        assertInWriteLock();
        
        Client::Context * ctx = cc().getContext();
        assert( ctx );
        assert( ctx->inDB( db , path ) );
        Database *database = ctx->db();
        assert( database->name == db );
        
        oplogCheckCloseDatabase( database ); // oplog caches some things, dirty its caches

        if( BackgroundOperation::inProgForDb(db) ) { 
            log() << "warning: bg op in prog during close db? " << db << endl;
        }

        /* important: kill all open cursors on the database */
        string prefix(db);
        prefix += '.';
        ClientCursor::invalidate(prefix.c_str());

        NamespaceDetailsTransient::clearForPrefix( prefix.c_str() );

        dbHolder.erase( db, path );
        ctx->clear();
        delete database; // closes files
    }

    StatusWithMatchExpression expressionParserWhereCallbackReal(const BSONElement& where) {
        if ( !haveClient() )
            return StatusWithMatchExpression( ErrorCodes::BadValue, "no current client needed for $where" );

        Client::Context* context = cc().getContext();
        if ( !context )
            return StatusWithMatchExpression( ErrorCodes::BadValue, "no context in $where parsing" );

        const char* ns = context->ns();
        if ( !ns )
            return StatusWithMatchExpression( ErrorCodes::BadValue, "no ns in $where parsing" );

        if ( !globalScriptEngine )
            return StatusWithMatchExpression( ErrorCodes::BadValue, "no globalScriptEngine in $where parsing" );

        auto_ptr<WhereMatchExpression> exp( new WhereMatchExpression() );
        if ( where.type() == String || where.type() == Code ) {
            Status s = exp->init( ns, where.valuestr(), BSONObj() );
            if ( !s.isOK() )
                return StatusWithMatchExpression( s );
            return StatusWithMatchExpression( exp.release() );
        }

        if ( where.type() == CodeWScope ) {
            Status s = exp->init( ns,
                                  where.codeWScopeCode(),
                                  BSONObj( where.codeWScopeScopeDataUnsafe() ) );
            if ( !s.isOK() )
                return StatusWithMatchExpression( s );
            return StatusWithMatchExpression( exp.release() );
        }

        return StatusWithMatchExpression( ErrorCodes::BadValue, "$where got bad type" );
    }

 string getDbContext() {
     stringstream ss;
     Client * c = currentClient.get();
     if ( c ) {
         Client::Context * cx = c->getContext();
         if ( cx ) {
             Database *database = cx->db();
             if ( database ) {
                 ss << database->name() << ' ';
                 ss << cx->ns() << ' ';
             }
         }
     }
     return ss.str();
 }

    Status IndexBuilder::build(TransactionExperiment* txn,
                               Client::Context& context ) const {

        string ns = _index["ns"].String();
        Database* db = context.db();
        Collection* c = db->getCollection( ns );
        if ( !c ) {
            c = db->getOrCreateCollection( ns );
            verify(c);
        }

        // Show which index we're building in the curop display.
        context.getClient()->curop()->setQuery(_index);

        Status status = c->getIndexCatalog()->createIndex( txn,
                                                           _index, 
                                                           true, 
                                                           IndexCatalog::SHUTDOWN_LEAVE_DIRTY );
        if ( status.code() == ErrorCodes::IndexAlreadyExists )
            return Status::OK();
        return status;
    }

 Status IndexBuilder::build( Client::Context& context ) const {
     string ns = _index["ns"].String();
     Database* db = context.db();
     Collection* c = db->getCollection( ns );
     if ( !c ) {
         c = db->getOrCreateCollection( ns );
         verify(c);
     }
     Status status = c->getIndexCatalog()->createIndex( _index, 
                                                        true, 
                                                        IndexCatalog::SHUTDOWN_LEAVE_DIRTY );
     if ( status.code() == ErrorCodes::IndexAlreadyExists )
         return Status::OK();
     return status;
 }

    /* we write to local.opload.$main:
         { ts : ..., op: ..., ns: ..., o: ... }
       ts: an OpTime timestamp
       op:
        "i" insert
        "u" update
        "d" delete
        "c" db cmd
        "db" declares presence of a database (ns is set to the db name + '.')
        "n" no op
       logNS - e.g. "local.oplog.$main"
       bb:
         if not null, specifies a boolean to pass along to the other side as b: param.
         used for "justOne" or "upsert" flags on 'd', 'u'
       first: true
         when set, indicates this is the first thing we have logged for this database.
         thus, the slave does not need to copy down all the data when it sees this.
    */
    static void _logOp(const char *opstr, const char *ns, const char *logNS, const BSONObj& obj, BSONObj *o2, bool *bb, const OpTime &ts ) {
        if ( strncmp(ns, "local.", 6) == 0 ){
            if ( strncmp(ns, "local.slaves", 12) == 0 ){
                resetSlaveCache();
            }
            return;
        }

        DEV assertInWriteLock();
        
        Client::Context context;
        
        /* we jump through a bunch of hoops here to avoid copying the obj buffer twice --
           instead we do a single copy to the destination position in the memory mapped file.
        */

        BSONObjBuilder b;
        b.appendTimestamp("ts", ts.asDate());
        b.append("op", opstr);
        b.append("ns", ns);
        if ( bb )
            b.appendBool("b", *bb);
        if ( o2 )
            b.append("o2", *o2);
        BSONObj partial = b.done();
        int posz = partial.objsize();
        int len = posz + obj.objsize() + 1 + 2 /*o:*/;

        Record *r;
        if ( strncmp( logNS, "local.", 6 ) == 0 ) { // For now, assume this is olog main
            if ( localOplogMainDetails == 0 ) {
                Client::Context ctx("local.", dbpath, 0, false);
                localOplogDB = ctx.db();
                localOplogMainDetails = nsdetails(logNS);
            }
            Client::Context ctx( "" , localOplogDB, false );
            r = theDataFileMgr.fast_oplog_insert(localOplogMainDetails, logNS, len);
        } else {
            Client::Context ctx( logNS, dbpath, 0, false );
            assert( nsdetails( logNS ) );
            r = theDataFileMgr.fast_oplog_insert( nsdetails( logNS ), logNS, len);
        }

        char *p = r->data;
        memcpy(p, partial.objdata(), posz);
        *((unsigned *)p) += obj.objsize() + 1 + 2;
        p += posz - 1;
        *p++ = (char) Object;
        *p++ = 'o';
        *p++ = 0;
        memcpy(p, obj.objdata(), obj.objsize());
        p += obj.objsize();
        *p = EOO;
        
        if ( logLevel >= 6 ) {
            BSONObj temp(r);
            log( 6 ) << "logging op:" << temp << endl;
        }
        
        context.getClient()->setLastOp( ts );
    }

    /* we write to local.opload.$main:
         { ts : ..., op: ..., ns: ..., o: ... }
       ts: an OpTime timestamp
       op:
        "i" insert
        "u" update
        "d" delete
        "c" db cmd
        "db" declares presence of a database (ns is set to the db name + '.')
        "n" no op
       logNS - where to log it.  0/null means "local.oplog.$main".
       bb:
         if not null, specifies a boolean to pass along to the other side as b: param.
         used for "justOne" or "upsert" flags on 'd', 'u'
       first: true
         when set, indicates this is the first thing we have logged for this database.
         thus, the slave does not need to copy down all the data when it sees this.

       note this is used for single collection logging even when --replSet is enabled.
    */
    static void _logOpOld(const char *opstr, const char *ns, const char *logNS, const BSONObj& obj, BSONObj *o2, bool *bb ) {
        DEV assertInWriteLock();
        static BufBuilder bufbuilder(8*1024);

        if ( strncmp(ns, "local.", 6) == 0 ) {
            if ( strncmp(ns, "local.slaves", 12) == 0 ) {
                resetSlaveCache();
            }
            return;
        }

        const OpTime ts = OpTime::now();
        Client::Context context;

        /* we jump through a bunch of hoops here to avoid copying the obj buffer twice --
           instead we do a single copy to the destination position in the memory mapped file.
        */

        bufbuilder.reset();
        BSONObjBuilder b(bufbuilder);
        b.appendTimestamp("ts", ts.asDate());
        b.append("op", opstr);
        b.append("ns", ns);
        if ( bb )
            b.appendBool("b", *bb);
        if ( o2 )
            b.append("o2", *o2);
        BSONObj partial = b.done(); // partial is everything except the o:... part.

        int po_sz = partial.objsize();
        int len = po_sz + obj.objsize() + 1 + 2 /*o:*/;

        Record *r;
        if( logNS == 0 ) {
            logNS = "local.oplog.$main";
            if ( localOplogMainDetails == 0 ) {
                Client::Context ctx( logNS , dbpath, 0, false);
                localDB = ctx.db();
                assert( localDB );
                localOplogMainDetails = nsdetails(logNS);
                assert( localOplogMainDetails );
            }
            Client::Context ctx( logNS , localDB, false );
            r = theDataFileMgr.fast_oplog_insert(localOplogMainDetails, logNS, len);
        }
        else {
            Client::Context ctx( logNS, dbpath, 0, false );
            assert( nsdetails( logNS ) );
            // first we allocate the space, then we fill it below.
            r = theDataFileMgr.fast_oplog_insert( nsdetails( logNS ), logNS, len);
        }

        append_O_Obj(r->data, partial, obj);

        context.getClient()->setLastOp( ts.asDate() );

        if ( logLevel >= 6 ) {
            BSONObj temp(r);
            log( 6 ) << "logging op:" << temp << endl;
        }

    }

 virtual ~Base() {
     OperationContextImpl txn;
     if ( !nsd() )
         return;
     _context.db()->dropCollection( &txn, ns() );
 }

        Base() : lk(ns()), _context( ns() ) {
            _database = _context.db();
            _collection = _database->getCollection( ns() );
            if ( _collection ) {
                _database->dropCollection( &_txn, ns() );
            }
            _collection = _database->createCollection( &_txn, ns() );

            addIndex( fromjson( "{\"a\":1}" ) );
        }

 Database* db() const {
     return _context.db();
 }

 virtual ~Base() {
     DurTransaction txn;
     if ( !nsd() )
         return;
     _context.db()->dropCollection( &txn, ns() );
 }