4 // Fraunhofer Institut fuer offene Kommunikationssysteme (FOKUS)
5 // Kompetenzzentrum fuer Satelitenkommunikation (SatCom)
6 // Stefan Bund <stefan.bund@fokus.fraunhofer.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
33 #include <boost/function.hpp>
34 #include <boost/utility.hpp>
35 #include <boost/call_traits.hpp>
36 #include <boost/integer.hpp>
37 #include <boost/date_time/posix_time/posix_time_types.hpp>
39 //#include "scheduler.mpp"
40 ///////////////////////////////hh.p////////////////////////////////////////
42 /** \brief SENF Project namespace */
45 /** \brief Singleton class to manage the event loop
47 This class manages a single select() type event loop. A customer of this class may register
48 any number of file descriptors with this class and pass callback functions to be called on
49 input, output or error. This functions are specified using boost::function objects (See <a
50 href="http://www.boost.org/doc/html/function.html">Boost.Function</a>)
52 The Scheduler is based on a generic handle representation. The only information needed from
53 a handle, is the intrinsic file descriptor. Any object for which the statement
55 int fd = retrieve_filehandle(object);
57 is valid and places the relevant file descriptor into fd can be used as a Handle type. There
58 is an implementation of retrieve_filehandle(int) within the library to handle explicit file
59 descriptors. The <a href="../../../Socket/doc/html/index.html">Socket library</a> provides an
60 implementation of <tt>retrieve_filehandle(FileHandle handle)</tt>. If you want to support
61 some other handle type, just define an appropriate \c retrieve_filehandle function <em>in
62 that types namespace</em>.
64 It is important to note, that for every combination of file descriptor and event, only a \e
65 single handler may be installed. Installing more handlers does not make sense. If you need
66 to distribute data to several interested parties, you must take care of this yourself.
68 \todo Fix EventId parameter (probably to int) to allow |-ing without casting ...
74 ///////////////////////////////////////////////////////////////////////////
77 /** \brief Types of file descriptor events */
78 enum EventId { EV_NONE=0,
79 EV_READ=1, EV_PRIO=2, EV_WRITE=4,
81 EV_HUP=8, EV_ERR=16 };
83 /** \brief Template typedef for Callback type
85 This is a template typedef (which does not exist in C++) that is, a template class whose
86 sole member is a typedef symbol defining the callback type given the handle type.
88 The Callback is any callable object taking a \c Handle and an \c EventId as argument.
90 template <class Handle>
91 struct GenericCallback {
92 typedef boost::function<void (typename boost::call_traits<Handle>::param_type,
96 /** \brief Scheduler time data type
98 Unsigned integer type representing scheduler time. Scheduler time is measured in
99 nanoseconds relative to some implementation defined reference time.
101 typedef boost::uint_fast64_t sched_time;
103 /** \brief Absolute time data type
105 Boost.DateTime datatype used to represent absolute date/time values.
107 typedef boost::posix_time::ptime abs_time;
109 /** \brief Callback type for timer events */
110 typedef boost::function<void ()> TimerCallback;
112 ///////////////////////////////////////////////////////////////////////////
113 ///\name Structors and default members
116 // private default constructor
117 // no copy constructor
118 // no copy assignment
119 // default destructor
120 // no conversion constructors
122 /** \brief Return Scheduler instance
124 This static member is used to access the singleton instance. This member is save to
125 return a correctly initialized Scheduler instance even if called at global construction
128 \implementation This static member just defines the Scheduler as a static method
129 variable. The C++ standard then provides above guarantee. The instance will be
130 initialized the first time, the code flow passes the variable declaration found in
133 static Scheduler & instance();
136 ///////////////////////////////////////////////////////////////////////////
138 template <class Handle>
139 void add(Handle const & handle,
140 typename GenericCallback<Handle>::Callback const & cb,
141 int eventMask = EV_ALL); ///< Add file handle event callback
142 /**< add() will add a callback to the Scheduler. The
143 callback will be called for the given type of event on
144 the given arbitrary file-descriptor or
145 handle-like object. If there already is a Callback
146 registered for one of the events requested, the new
147 handler will replace the old one.
148 \param[in] handle file descriptor or handle providing
149 the Handle interface defined above.
150 \param[in] cb callback
151 \param[in] eventMask arbitrary combination via '|'
152 operator of EventId designators. */
153 template <class Handle>
154 void remove(Handle const & handle, int eventMask = EV_ALL); ///< Remove event callback
155 /**< remove() will remove any callback registered for any of
156 the given events on the given file descriptor or handle
158 \param[in] handle file descriptor or handle providing
159 the Handle interface defined above.
160 \param[in] eventMask arbitrary combination via '|'
161 operator of EventId designators. */
163 void timeout(sched_time timeout, TimerCallback const & cb); ///< Add timeout event
164 /**< \param[in] timeout timeout in nanoseconds
165 \param[in] cb callback to call after \a timeout
167 \todo Return some kind of handle/pointer and add
168 support to update or revoke a timeout */
170 void process(); ///< Event handler main loop
171 /**< This member must be called at some time to enter the
172 event handler main loop. Only while this function is
173 running any events are handled. The call will return
174 only, if any callback calls terminate(). */
175 void terminate(); ///< Called by callbacks to terminate the main loop
176 /**< This member may be called by any callback to tell the
177 main loop to terminate. The main loop will return to
178 it's caller after the currently running callback
181 abs_time abstime(sched_time time) const; ///< Convert scheduler time to absolute time
182 /**< This member converts a scheduler time value into an
183 absolute Boost.DateTime value.
184 \note You should not base timeout calculations on this
185 absolute time value. Scheduler time is guaranteed
186 to be monotonous, absolute time may be
187 non-monotonous if the system date/time is
190 sched_time schedtime(abs_time time) const; ///< Convert absolute time to scheduler time
191 /**< This member converst an absolute time value into the
192 corresponding scheduler time.
195 sched_time now() const; ///< Return current date/time
196 /**< The return value represents the current date/time in
197 scheduler time representation */
199 sched_time eventTime() const; ///< Return date/time of last event
204 typedef boost::function<void (EventId)> SimpleCallback;
206 static unsigned const MinTimeout = 1000;
210 void do_add(int fd, SimpleCallback const & cb, int eventMask = EV_ALL);
211 void do_remove(int fd, int eventMask = EV_ALL);
213 /** \brief Descriptor event specification
217 SimpleCallback cb_read;
218 SimpleCallback cb_prio;
219 SimpleCallback cb_write;
221 int epollMask() const;
224 /** \brief Timer event specification
228 TimerSpec() : timeout(), cb() {}
229 TimerSpec(sched_time timeout_, TimerCallback cb_)
230 : timeout(timeout_), cb(cb_) {}
232 bool operator< (TimerSpec const & other) const
233 { return timeout > other.timeout; }
239 typedef std::map<int,EventSpec> FdTable;
240 typedef std::priority_queue<TimerSpec> TimerQueue;
243 TimerQueue timerQueue_;
249 /** \brief Default file descriptor accessor
251 retrieve_filehandle() provides the Scheduler with support for explicit file descriptors as
252 file handle argument.
256 int retrieve_filehandle(int fd);
260 ///////////////////////////////hh.e////////////////////////////////////////
261 #include "Scheduler.cci"
262 //#include "Scheduler.ct"
263 #include "Scheduler.cti"
270 // c-file-style: "senf"
271 // indent-tabs-mode: nil
272 // ispell-local-dictionary: "american"
273 // compile-command: "scons -u test"
274 // comment-column: 40