4 // Fraunhofer Institute for Open Communication Systems (FOKUS)
5 // Competence Center NETwork research (NET), St. Augustin, GERMANY
6 // Stefan Bund <g0dil@berlios.de>
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 2 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the
20 // Free Software Foundation, Inc.,
21 // 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
24 \brief Scheduler public header
28 #define HH_Scheduler_ 1
31 #include "../Utils/Logger/SenfLog.hh"
33 #include "TimerEvent.hh"
34 #include "SignalEvent.hh"
36 //#include "scheduler.mpp"
37 ///////////////////////////////hh.p////////////////////////////////////////
41 /** \brief The Scheduler interface
43 The %scheduler API is comprised of two parts:
45 \li Specific \ref sched_objects, one for each type of event.
46 \li Some <a href="#autotoc-7.">generic functions</a> implemented in the \ref senf::scheduler
49 Events are registered via the respective event class. The (global) functions are used to enter
50 the application main-loop or query for global information.
55 \section sched_objects Event classes
57 The Scheduler is based on the RAII principle: Every event is represented by a class
58 instance. The event is registered in the constructor and removed by the destructor of that
59 instance. This implementation automatically links the lifetime of an event with the lifetime of
60 the object resposible for it's creation.
62 Every event registration is represented by an instance of an event specific class:
64 \li senf::scheduler::FdEvent for file descriptor events
65 \li senf::scheduler::TimerEvent for single-shot deadline timer events
66 \li senf::scheduler::SignalEvent for UNIX signal events
68 These instance are owned and managed by the user of the scheduler \e not by the scheduler so the
69 RAII concept can be used.
74 SomeSocketHandle handle_;
75 senf::scheduler::FdEvent event_;
78 SomeServer(SomeSocketHandle handle)
80 event_ ("SomeServer handler", senf::membind(&SomeServer::readData, this),
81 handle, senf::scheduler::FdEvent::EV_READ)
84 void readData(int events)
86 // read data from handle_, check for eof and so on.
91 The event is defined as a class member variable. When the event member is initialized in the
92 constructor, the event is automatically registered (except if the optional \a initiallyEnabled
93 flag argument is set to \c false). The Destructor will automatically remove the event from the
94 scheduler and ensure, that no dead code is called accidentally.
96 The process is the same for the other event types or when registering multiple events. For
97 detailed information on the constructor arguments and other features see the event class
98 documentation referenced below.
101 \section sched_handlers Specifying handlers
103 All handlers are specified as generic <a
104 href="http://www.boost.org/doc/html/function.html">Boost.Function</a> objects. This allows to
105 pass any callable as a handler. Depending on the type of handler, some additional arguments may
106 be passed to the handler by the %scheduler.
108 If you need to pass additional information to your handler, use <a
109 href="http://www.boost.org/libs/bind/bind.html">Boost.Bind</a>:
111 // Handle callback function
112 void callback(UDPv4ClientSocketHandle handle, senf::Scheduler::EventId event) {..}
113 // Pass 'handle' as additional first argument to callback()
114 senf::scheduler::FdEvent event ("name", boost::bind(&callback, handle, _1),
115 handle, senf::scheduler::FdEvent::EV_READ);
117 void timeout( int n) {..}
118 // Call timeout() handler with argument 'n'
119 senf::scheduler::TimerEvent timer ("name", boost::bind(&timeout, n),
120 senf::ClockService::now() + senf::ClockService::seconds(1));
123 To use member-functions as callbacks, use either <a
124 href="http://www.boost.org/libs/bind/bind.html">Boost.Bind</a> or senf::membind()
126 // e.g. in Foo::Foo() constructor:
129 readevent_ ("Foo read", senf::membind(&Foo::callback, this),
130 handle_, senf::scheduler::FdEvent::EV_READ)
134 The handler is identified by an arbitrary, user specified name. This name is used in error
135 messages to identify the failing handler.
138 \section sched_exec Executing the Scheduler
140 To enter the scheduler main-loop, call
143 senf::scheduler::process();
146 This call will only return in two cases:
148 \li When a handler calls senf::scheduler::terminate()
149 \li When there is no active file descriptor or timer event.
151 Additional <a href="#autotoc-7.">generic functions</a> provide information and %scheduler
154 \section sched_container Event objects and container classes
156 As the event objects are \e not copyable, they cannot be placed into ordinary
157 containers. However, it is quite simple to use pointer containers to hold event instances:
160 #include <boost/ptr_container/ptr_map.hpp>
161 #include <boost/bind.hpp>
170 new senf::scheduler::FdEvent("foo", boost::bind(&callback, this, fd, _1), fd,
171 senf::scheduler::FdEvent::EV_READ) );
174 void callback(int fd, int events)
176 FdEvent & event (fdEvents_[fd]);
185 boost::ptr_map<int, FdEvent> fdEvents_;
189 The pointer container API is (almost) completely identical to the corresponding standard library
190 container API. The only difference is, that all elements added to the container \e must be
191 created via \c new and that the pointer containers themselves are \e not copyable (ok, they are,
192 if the elements are cloneable ...). See <a
193 href="http://www.boost.org/doc/libs/1_36_0/libs/ptr_container/doc/ptr_container.html">Boost.PointerContainer</a>
194 for the pointer container library reference.
196 \todo Fix the file support to use threads (?) fork (?) and a pipe so it works reliably even
199 namespace scheduler {
201 /** \brief Event handler main loop
203 This member must be called at some time to enter the event handler main loop. Only while
204 this function is running any events are handled. The call will return if
205 \li a callback calls terminate()
206 \li the run queue becomes empty.
210 /** \brief Called by callbacks to terminate the main loop
212 This member may be called by any callback to tell the main loop to terminate. The main loop
213 will return to it's caller after the currently running callback returns.
217 /** \brief Return timestamp of last event
219 This is the timestamp, the last event has been signaled. This is the real time at which the
220 event is delivered \e not the time it should have been delivered (in the case of timers).
222 ClockService::clock_type eventTime();
224 /** \brief Set task watchdog timeout */
225 void taskTimeout(unsigned ms);
227 /** \brief Current task watchdog timeout */
228 unsigned taskTimeout();
230 /** \brief Number of watchdog events */
231 unsigned hangCount();
233 /** \brief Restart scheduler
235 This call will restart all scheduler dispatchers (timers, signals, file descriptors). This
236 is necessary after a fork().
237 \warning This call will \e remove all registered events from the scheduler
241 /** \brief Return \c true, if any event is registered, \c false otherwise. */
244 /** \brief %scheduler specific time source for Utils/Logger framework
246 This time source may be used to provide timing information for log messages within the
247 Utils/Logger framework. This time source will use Scheduler::eventTime() to provide timing
251 senf::log::timeSource<senf::scheduler::LogTimeSource>();
254 Using this information reduces the number of necessary ClockService::now() calls and thus
255 the number of system calls.
257 struct LogTimeSource : public senf::log::TimeSource
259 senf::log::time_type operator()() const;
264 ///////////////////////////////hh.e////////////////////////////////////////
265 #include "Scheduler.cci"
266 //#include "Scheduler.ct"
267 //#include "Scheduler.cti"
274 // c-file-style: "senf"
275 // indent-tabs-mode: nil
276 // ispell-local-dictionary: "american"
277 // compile-command: "scons -u test"
278 // comment-column: 40