// $Id$
//
// Copyright (C) 2006
-// Fraunhofer Institut fuer offene Kommunikationssysteme (FOKUS)
-// Kompetenzzentrum fuer Satelitenkommunikation (SatCom)
-// Stefan Bund <stefan.bund@fokus.fraunhofer.de>
+// Fraunhofer Institute for Open Communication Systems (FOKUS)
+// Competence Center NETwork research (NET), St. Augustin, GERMANY
+// Stefan Bund <g0dil@berlios.de>
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
#define HH_Scheduler_ 1
// Custom includes
+#include <signal.h>
+#include <setjmp.h>
#include <map>
#include <queue>
#include <boost/function.hpp>
#include <boost/call_traits.hpp>
#include <boost/integer.hpp>
#include "ClockService.hh"
+#include "../Utils/Logger/SenfLog.hh"
//#include "scheduler.mpp"
///////////////////////////////hh.p////////////////////////////////////////
/** \brief Singleton class to manage the event loop
- This class manages a single select() type event loop. A customer of this class may register
- any number of file descriptors with this class and pass callback functions to be called on
- input, output or error. This functions are specified using boost::function objects (See <a
- href="http://www.boost.org/doc/html/function.html">Boost.Function</a>)
+ The %scheduler singleton manages the central event loop. It manages and dispatches all types
+ of events managed by the scheduler library:
+ \li File descriptor notifications
+ \li Timeouts
+ \li UNIX Signals
- The Scheduler is based on a generic handle representation. The only information needed from
- a handle, is the intrinsic file descriptor. Any object for which the statement
+ The %scheduler is entered by calling it's process() member. This call will continue to run as
+ long as there is something to do, or until one of the handlers calls terminate(). The
+ %scheduler has 'something to do' as long as there is any file descriptor or timeout active.
+
+ The %scheduler only provides low level primitive scheduling capability. Additional helpers
+ are defined on top of this functionality (e.g. ReadHelper or WriteHelper or the interval
+ timers of the PPI).
+
+
+ \section sched_handlers Specifying handlers
+
+ All handlers are passed as generic <a
+ href="http://www.boost.org/doc/html/function.html">Boost.Function</a> objects. This allows
+ to pass any callable as a handler. Depending on the type of handler, some additional
+ arguments may be passed to the handler by the %scheduler.
+
+ If you need to pass additional information to your handler, use <a
+ href="http://www.boost.org/libs/bind/bind.html">Boost.Bind</a>:
+ \code
+ // Handle callback function
+ void callback(UDPv4ClientSocketHandle handle, senf::Scheduler::EventId event) {..}
+ // Pass 'handle' as additional first argument to callback()
+ Scheduler::instance().add(handle, boost::bind(&callback, handle, _1), EV_READ)
+ // Timeout function
+ void timeout( int n) {..}
+ // Call timeout() handler with argument 'n'
+ Scheduler::instance().timeout(boost::bind(&timeout, n))
+ \endcode
+
+ To use member-functions as callbacks, use either <a
+ href="http://www.boost.org/libs/bind/bind.html">Boost.Bind</a> or senf::membind()
+ \code
+ // e.g. in Foo::Foo() constructor:
+ Scheduler::instance().add(handle_, senf::membind(&Foo::callback, this)), EV_READ)
+ \endcode
+
+
+ \section sched_fd Registering file descriptors
+
+ File descriptors are managed using add() or remove()
+ \code
+ Scheduler::instance().add(handle, &callback, EV_ALL);
+ Scheduler::instance().remove(handle);
+ \endcode
+
+ The callback will be called with one additional argument. This argument is the event mask of
+ type EventId. This mask will tell, which of the registered events are signaled. The
+ additional flags EV_HUP or EV_ERR (on hangup or error condition) may be set additionally.
+
+ Only a single handler may be registered for any combination of file descriptor and event
+ (registering multiple callbacks for a single fd and event does not make sense).
+
+ The %scheduler will accept any object as \a handle argument as long as retrieve_filehandle()
+ may be called on that object
+ \code
+ int fd = retrieve_filehandle(handle);
+ \endcode
+ to fetch the file handle given some abstract handle type. retrieve_filehandle() will be
+ found using ADL depending on the argument namespace. A default implementation is provided
+ for \c int arguments (file descriptors)
+
+
+ \section sched_timers Registering timers
+
+ The %scheduler has very simple timer support. There is only one type of timer: A single-shot
+ deadline timer. More complex timers are built based on this. Timers are managed using
+ timeout() and cancelTimeout()
\code
- int fd = retrieve_filehandle(object);
+ int id = Scheduler::instance().timeout(Scheduler::instance().eventTime() + ClockService::milliseconds(100),
+ &callback);
+ Scheduler::instance().cancelTimeout(id);
+ \endcode
+ Timing is based on the ClockService, which provides a high resolution and strictly
+ monotonous time source. Registering a timeout will fire the callback when the target time is
+ reached. The timer may be canceled by passing the returned \a id to cancelTimeout().
+
+ There are two parameters which adjust the exact: \a timeoutEarly and \a timeoutAdjust. \a
+ timeoutEarly is the time, a callback may be called before the deadline time is
+ reached. Setting this value below the scheduling granularity of the kernel will have the
+ %scheduler go into a <em>busy wait</em> (that is, an endless loop consuming 100% of CPU
+ recources) until the deadline time is reached! This is seldom desired. The default setting
+ of 11ms is adequate in most cases (it's slightly above the lowest linux scheduling
+ granularity).
+
+ The other timeout scheduling parameter is \a timeoutAdjust. This value will be added to the
+ timeout value before calculating the next delay value thereby compensating for \a
+ timeoutEarly. By default, this value is set to 0 but may be changed if needed.
+
+
+ \section sched_signals Registering POSIX/UNIX signals
+
+ The %scheduler also incorporates standard POSIX/UNIX signals. Signals registered with the
+ %scheduler will be handled \e synchronously within the event loop.
+ \code
+ Scheduler::instance().registerSignal(SIGUSR1, &callback);
+ Scheduler::instance().unregisterSignal(SIGUSR1);
\endcode
- is valid and places the relevant file descriptor into fd can be used as a Handle type. There
- is an implementation of retrieve_filehandle(int) within the library to handle explicit file
- descriptors. The <a href="../../../Socket/doc/html/index.html">Socket library</a> provides an
- implementation of <tt>retrieve_filehandle(FileHandle handle)</tt>. If you want to support
- some other handle type, just define an appropriate \c retrieve_filehandle function <em>in
- that types namespace</em>.
+ When registering a signal with the %scheduler, that signal will automatically be blocked so
+ it can be handled within the %scheduler.
- It is important to note, that for every combination of file descriptor and event, only a \e
- single handler may be installed. Installing more handlers does not make sense. If you need
- to distribute data to several interested parties, you must take care of this yourself.
+ A registered signal does \e not count as 'something to do'. It is therefore not possible to
+ wait for signals \e only.
\todo Fix EventId parameter (probably to int) to allow |-ing without casting ...
+
+ \todo Fix the file support to use threads (?) fork (?) and a pipe so it works reliably even
+ over e.g. NFS.
*/
class Scheduler
: boost::noncopyable
{
public:
+
+ SENF_LOG_CLASS_AREA();
+
///////////////////////////////////////////////////////////////////////////
// Types
- /** \brief Types of file descriptor events */
- enum EventId { EV_NONE=0,
- EV_READ=1, EV_PRIO=2, EV_WRITE=4,
- EV_ALL=7,
- EV_HUP=8, EV_ERR=16 };
+ /** \brief Types of file descriptor events
+
+ These events are grouped into to classes:
+ \li Ordinary file descriptor events for which handlers may be registered. These are
+ EV_READ, EV_PRIO and EV_WRITE. EV_ALL is a combination of these three.
+ \li Error flags. These additional flags may be passed to a handler to pass an error
+ condition to the handler.
+ */
+ enum EventId {
+ EV_NONE = 0 /**< No event */
+ , EV_READ = 1 /**< File descriptor is readable */
+ , EV_PRIO = 2 /**< File descriptor has OOB data */
+ , EV_WRITE = 4 /**< File descriptor is writable */
+ , EV_ALL = 7 /**< Used to register all events at once (read/prio/write) */
+ , EV_HUP = 8 /**< Hangup condition on file handle */
+ , EV_ERR = 16 /**< Error condition on file handle */
+ };
/** \brief Template typedef for Callback type
sole member is a typedef symbol defining the callback type given the handle type.
The Callback is any callable object taking a \c Handle and an \c EventId as argument.
+ \code
+ template <class Handle>
+ struct GenericCallback {
+ typedef boost::function<void (typename boost::call_traits<Handle>::param_type,
+ EventId) > Callback;
+ };
+ \endcode
*/
- template <class Handle>
- struct GenericCallback {
- typedef boost::function<void (typename boost::call_traits<Handle>::param_type,
- EventId) > Callback;
- };
+ typedef boost::function<void (EventId)> FdCallback;
/** \brief Callback type for timer events */
- typedef boost::function<void ()> TimerCallback;
+ typedef boost::function<void ()> SimpleCallback;
///////////////////////////////////////////////////////////////////////////
///\name Structors and default members
// default destructor
// no conversion constructors
- /** \brief Return Scheduler instance
+ /** \brief Return %scheduler instance
This static member is used to access the singleton instance. This member is save to
- return a correctly initialized Scheduler instance even if called at global construction
+ return a correctly initialized %scheduler instance even if called at global construction
time
- \implementation This static member just defines the Scheduler as a static method
+ \implementation This static member just defines the %scheduler as a static method
variable. The C++ standard then provides above guarantee. The instance will be
initialized the first time, the code flow passes the variable declaration found in
the instance() body.
///@}
///////////////////////////////////////////////////////////////////////////
+ ///\name File Descriptors
+ ///\{
+
template <class Handle>
- void add(Handle const & handle,
- typename GenericCallback<Handle>::Callback const & cb,
+ void add(Handle const & handle, FdCallback const & cb,
int eventMask = EV_ALL); ///< Add file handle event callback
- /**< add() will add a callback to the Scheduler. The
+ /**< add() will add a callback to the %scheduler. The
callback will be called for the given type of event on
the given arbitrary file-descriptor or
handle-like object. If there already is a Callback
the Handle interface defined above.
\param[in] cb callback
\param[in] eventMask arbitrary combination via '|'
- operator of EventId designators. */
+ operator of \ref senf::Scheduler::EventId "EventId"
+ designators. */
template <class Handle>
void remove(Handle const & handle, int eventMask = EV_ALL); ///< Remove event callback
/**< remove() will remove any callback registered for any of
\param[in] handle file descriptor or handle providing
the Handle interface defined above.
\param[in] eventMask arbitrary combination via '|'
- operator of EventId designators. */
+ operator of \ref senf::Scheduler::EventId "EventId"
+ designators. */
+ ///\}
+
+ ///\name Timeouts
+ ///\{
- unsigned timeout(ClockService::clock_type timeout, TimerCallback const & cb);
+ unsigned timeout(ClockService::clock_type timeout, SimpleCallback const & cb);
///< Add timeout event
/**< \param[in] timeout timeout in nanoseconds
\param[in] cb callback to call after \a timeout
- milliseconds
- \todo Return some kind of handle/pointer and add
- support to update or revoke a timeout */
+ milliseconds */
+
+ void cancelTimeout(unsigned id); ///< Cancel timeout \a id
+
+ ClockService::clock_type timeoutEarly() const;
+ ///< Fetch the \a timeoutEarly parameter
+ void timeoutEarly(ClockService::clock_type v);
+ ///< Set the \a timeoutEarly parameter
+
+ ClockService::clock_type timeoutAdjust() const;\
+ ///< Fetch the \a timeoutAdjust parameter
+ void timeoutAdjust(ClockService::clock_type v);
+ ///< Set the \a timeoutAdjust parameter
+
+ ///\}
+
+ ///\name Signal handlers
+ ///\{
+
+ void registerSignal(unsigned signal, SimpleCallback const & cb);
+ ///< Add signal handler
+ /**< \param[in] signal signal number to register handler for
+ \param[in] cb callback to call whenever \a signal is
+ delivered. */
- void cancelTimeout(unsigned id);
+ void unregisterSignal(unsigned signal);
+ ///< Remove signal handler for \a signal
+
+ /// The signal number passed to registerSignal or unregisterSignal is invalid
+ struct InvalidSignalNumberException : public senf::Exception
+ { InvalidSignalNumberException()
+ : senf::Exception("senf::Scheduler::InvalidSignalNumberException"){} };
+
+
+ ///\}
void process(); ///< Event handler main loop
/**< This member must be called at some time to enter the
event handler main loop. Only while this function is
running any events are handled. The call will return
only, if any callback calls terminate(). */
+
void terminate(); ///< Called by callbacks to terminate the main loop
/**< This member may be called by any callback to tell the
main loop to terminate. The main loop will return to
protected:
private:
- typedef boost::function<void (EventId)> SimpleCallback;
-
Scheduler();
- void do_add(int fd, SimpleCallback const & cb, int eventMask = EV_ALL);
+ void do_add(int fd, FdCallback const & cb, int eventMask = EV_ALL);
void do_remove(int fd, int eventMask = EV_ALL);
+ void registerSigHandlers();
+ static void sigHandler(int signal, ::siginfo_t * siginfo, void *);
+
+# ifndef DOXYGEN
+
/** \brief Descriptor event specification
\internal */
struct EventSpec
{
- SimpleCallback cb_read;
- SimpleCallback cb_prio;
- SimpleCallback cb_write;
+ FdCallback cb_read;
+ FdCallback cb_prio;
+ FdCallback cb_write;
+
+ EventSpec() : file(false) {}
int epollMask() const;
+
+ bool file;
};
/** \brief Timer event specification
struct TimerSpec
{
TimerSpec() : timeout(), cb() {}
- TimerSpec(ClockService::clock_type timeout_, TimerCallback cb_, unsigned id_)
+ TimerSpec(ClockService::clock_type timeout_, SimpleCallback cb_, unsigned id_)
: timeout(timeout_), cb(cb_), id(id_), canceled(false) {}
bool operator< (TimerSpec const & other) const
{ return timeout > other.timeout; }
ClockService::clock_type timeout;
- TimerCallback cb;
+ SimpleCallback cb;
unsigned id;
bool canceled;
};
+# endif
+
typedef std::map<int,EventSpec> FdTable;
typedef std::map<unsigned,TimerSpec> TimerMap; // sorted by id
+ typedef std::vector<unsigned> FdEraseList;
+
+# ifndef DOXYGEN
struct TimerSpecCompare
{
result_type operator()(first_argument_type a, second_argument_type b);
};
+# endif
+
typedef std::priority_queue<TimerMap::iterator, std::vector<TimerMap::iterator>,
TimerSpecCompare> TimerQueue; // sorted by time
+ typedef std::vector<SimpleCallback> SigHandlers;
+
FdTable fdTable_;
+ FdEraseList fdErase_;
+ unsigned files_;
+
unsigned timerIdCounter_;
TimerQueue timerQueue_;
TimerMap timerMap_;
+
+ SigHandlers sigHandlers_;
+ ::sigset_t sigset_;
+ int sigpipe_[2];
+
int epollFd_;
bool terminate_;
ClockService::clock_type eventTime_;
+ ClockService::clock_type eventEarly_;
+ ClockService::clock_type eventAdjust_;
};
/** \brief Default file descriptor accessor
- retrieve_filehandle() provides the Scheduler with support for explicit file descriptors as
+ retrieve_filehandle() provides the %scheduler with support for explicit file descriptors as
file handle argument.
\relates Scheduler
*/
int retrieve_filehandle(int fd);
+ /** \brief %scheduler specific time source for Utils/Logger framework
+
+ This time source may be used to provide timing information for log messages within the
+ Utils/Logger framework. This time source will use Scheduler::eventTime() to provide timing
+ information.
+ */
+ struct SchedulerLogTimeSource : public senf::log::TimeSource
+ {
+ boost::posix_time::ptime operator()() const;
+ };
+
}
///////////////////////////////hh.e////////////////////////////////////////
projects / senf.git / blobdiff