// mongo/shell/shell_utils_launcher.h
/*
 *    Copyright 2010 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 <boost/filesystem/convenience.hpp>
#include <boost/thread/recursive_mutex.hpp>
#include <map>
#include <sstream>
#include <string>
#include <vector>
#include <utility>

#include "mongo/bson/bsonobj.h"
#include "mongo/platform/process_id.h"

namespace mongo {

    class Scope;
    
    namespace shell_utils {

        // Scoped management of mongo program instances.  Simple implementation:
        // destructor kills all mongod instances created by the shell.
        struct MongoProgramScope {
            MongoProgramScope() {} // Avoid 'unused variable' warning.
            ~MongoProgramScope();
        };
        void KillMongoProgramInstances();
        
        void goingAwaySoon();
        void installShellUtilsLauncher( Scope& scope );
        
        /** Record log lines from concurrent programs.  All public members are thread safe. */
        class ProgramOutputMultiplexer {
        public:
            void appendLine( int port, ProcessId pid, const char *line );
            /** @return up to 100000 characters of the most recent log output. */
            std::string str() const;
            void clear();
        private:
            std::stringstream _buffer;
        };

        /**
         * A registry of spawned programs that are identified by a bound port or else a system pid.
         * All public member functions are thread safe.
         *
         * TODO: Clean this up to make the semantics more consistent between pids and ports
         */
        class ProgramRegistry {
        public:

            bool isPortRegistered( int port ) const;
            /** @return pid for a registered port. */
            ProcessId pidForPort( int port ) const;
            /** @return port (-1 if doesn't exist) for a registered pid. */
            int portForPid( ProcessId pid ) const;
            /** Register an unregistered port. */
            void registerPort( int port, ProcessId pid, int output );
            void deletePort( int port );
            void getRegisteredPorts( std::vector<int> &ports );

            bool isPidRegistered( ProcessId pid ) const;
            /** Register an unregistered pid. */
            void registerPid( ProcessId pid, int output );
            void deletePid( ProcessId pid );
            void getRegisteredPids( std::vector<ProcessId> &pids );

        private:
            std::map<int,std::pair<ProcessId,int> > _ports;
            std::map<ProcessId,int> _pids;
            mutable boost::recursive_mutex _mutex;

#ifdef _WIN32
        public:
            std::map<ProcessId,HANDLE> _handles;
#endif
        };
        
        /** Helper class for launching a program and logging its output. */
        class ProgramRunner {
        public:
            /** @param args The program's arguments, including the program name. */
            ProgramRunner( const BSONObj &args );
            /** Launch the program. */
            void start();                        
            /** Continuously read the program's output, generally from a special purpose thread. */
            void operator()();
            ProcessId pid() const { return _pid; }
            int port() const { return _port; }

        private:
            boost::filesystem::path findProgram( const std::string &prog );
            void launchProcess( int child_stdout );
            
            std::vector<std::string> _argv;
            int _port;
            int _pipe;
            ProcessId _pid;
        };
    }
}