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/**********
This library is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the
Free Software Foundation; either version 2.1 of the License, or (at your
option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
This library 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 Lesser General Public License for
more details.
You should have received a copy of the GNU Lesser General Public License
along with this library; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
**********/
// Copyright (c) 1996-2007 Live Networks, Inc. All rights reserved.
// Usage Environment
// C++ header
#ifndef _USAGE_ENVIRONMENT_HH
#define _USAGE_ENVIRONMENT_HH
#ifndef _USAGEENVIRONMENT_VERSION_HH
#include "UsageEnvironment_version.hh"
#endif
#ifndef _NETCOMMON_H
#include "NetCommon.h"
#endif
#ifndef _STRDUP_HH
// "strDup()" is used often, so include this here, so everyone gets it:
#include "strDup.hh"
#endif
#ifndef NULL
#define NULL 0
#endif
#ifdef __BORLANDC__
#define _setmode setmode
#define _O_BINARY O_BINARY
#endif
class TaskScheduler; // forward
// An abstract base class, subclassed for each use of the library
class UsageEnvironment {
public:
void reclaim();
// task scheduler:
TaskScheduler& taskScheduler() const {return fScheduler;}
// result message handling:
typedef char const* MsgString;
virtual MsgString getResultMsg() const = 0;
virtual void setResultMsg(MsgString msg) = 0;
virtual void setResultMsg(MsgString msg1, MsgString msg2) = 0;
virtual void setResultMsg(MsgString msg1, MsgString msg2, MsgString msg3) = 0;
virtual void setResultErrMsg(MsgString msg) = 0;
// like setResultMsg(), except that an 'errno' message is appended
virtual void appendToResultMsg(MsgString msg) = 0;
virtual void reportBackgroundError() = 0;
// used to report a (previously set) error message within
// a background event
// 'errno'
virtual int getErrno() const = 0;
// 'console' output:
virtual UsageEnvironment& operator<<(char const* str) = 0;
virtual UsageEnvironment& operator<<(int i) = 0;
virtual UsageEnvironment& operator<<(unsigned u) = 0;
virtual UsageEnvironment& operator<<(double d) = 0;
virtual UsageEnvironment& operator<<(void* p) = 0;
// a pointer to additional, optional, client-specific state
void* liveMediaPriv;
void* groupsockPriv;
protected:
UsageEnvironment(TaskScheduler& scheduler); // abstract base class
virtual ~UsageEnvironment(); // we are deleted only by reclaim()
private:
TaskScheduler& fScheduler;
};
typedef void TaskFunc(void* clientData);
typedef void* TaskToken;
class TaskScheduler {
public:
virtual ~TaskScheduler();
virtual TaskToken scheduleDelayedTask(int64_t microseconds, TaskFunc* proc,
void* clientData) = 0;
// Schedules a task to occur (after a delay) when we next
// reach a scheduling point.
// (Does not delay if "microseconds" <= 0)
// Returns a token that can be used in a subsequent call to
// unscheduleDelayedTask()
virtual void unscheduleDelayedTask(TaskToken& prevTask) = 0;
// (Has no effect if "prevTask" == NULL)
// Sets "prevTask" to NULL afterwards.
virtual void rescheduleDelayedTask(TaskToken& task,
int64_t microseconds, TaskFunc* proc,
void* clientData);
// Combines "unscheduleDelayedTask()" with "scheduleDelayedTask()"
// (setting "task" to the new task token).
// For handling socket reads in the background:
typedef void BackgroundHandlerProc(void* clientData, int mask);
// Possible bits to set in "mask". (These are deliberately defined
// the same as those in Tcl, to make a Tcl-based subclass easy.)
#define SOCKET_READABLE (1<<1)
#define SOCKET_WRITABLE (1<<2)
#define SOCKET_EXCEPTION (1<<3)
virtual void turnOnBackgroundReadHandling(int socketNum,
BackgroundHandlerProc* handlerProc,
void* clientData) = 0;
virtual void turnOffBackgroundReadHandling(int socketNum) = 0;
virtual void doEventLoop(char* watchVariable = NULL) = 0;
// Stops the current thread of control from proceeding,
// but allows delayed tasks (and/or background I/O handling)
// to proceed.
// (If "watchVariable" is not NULL, then we return from this
// routine when *watchVariable != 0)
protected:
TaskScheduler(); // abstract base class
};
#endif
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