Created the minicron system. This is a cute little cron like implementation

that allows a program to signal slots on a schedule, possibly a dynamic
schedule.

3 files changed, 639 insertions, 0 deletions

diff --git a/src/minicron.cpp b/src/minicron.cpp
new file mode 100644
index 0000000..f20a382
--- /dev/null
+++ b/src/minicron.cpp
@@ -0,0 +1,360 @@
+#include "bu/minicron.h"
+
+#include <stdlib.h>
+#include <time.h>
+
+Bu::MiniCron::MiniCron() :
+        jidNext( 1 )
+{
+}
+
+Bu::MiniCron::~MiniCron()
+{
+}
+
+bool Bu::MiniCron::hasJobs()
+{
+        return !hJobs.isEmpty();
+}
+
+time_t Bu::MiniCron::getNextRun()
+{
+        if( hasJobs() )
+                return hJobs.peek()->getNextRun();
+        return -1;
+}
+
+void Bu::MiniCron::poll()
+{
+        time_t tNow = time( NULL );
+
+        while( !hJobs.isEmpty() )
+        {
+                if( hJobs.peek()->getNextRun() <= tNow )
+                {
+                        Job *pJob = hJobs.dequeue();
+                        pJob->run();
+                        if( pJob->bContinue )
+                        {
+                                hJobs.enqueue( pJob );
+                        }
+                        else
+                        {
+                                delete pJob;
+                        }
+                }
+                else
+                {
+                        break;
+                }
+        }
+}
+
+Bu::MiniCron::JobId Bu::MiniCron::addJob( Bu::MiniCron::CronSignal sigJob,
+                const Bu::MiniCron::Timer &t )
+{
+        JobId jid = jidNext++;
+        Job *pJob = new Job( jid );
+        pJob->sigJob = sigJob;
+        pJob->pTimer = t.clone();
+        pJob->tNextRun = pJob->pTimer->nextTime();
+        hJobs.enqueue( pJob );
+
+        return jid;
+}
+
+Bu::MiniCron::JobId Bu::MiniCron::addJobOnce( Bu::MiniCron::CronSignal sigJob,
+                const Bu::MiniCron::Timer &t )
+{
+        JobId jid = jidNext++;
+        Job *pJob = new Job( jid, false );
+        pJob->sigJob = sigJob;
+        pJob->pTimer = t.clone();
+        pJob->tNextRun = pJob->pTimer->nextTime();
+        hJobs.enqueue( pJob );
+
+        return jid;
+}
+
+void Bu::MiniCron::removeJob( JobId jid )
+{
+        Bu::List<Job *> lJobs;
+        while( !hJobs.isEmpty() )
+        {
+                Job *pJob = hJobs.dequeue();
+                if( pJob->getId() == jid )
+                {
+                        delete pJob;
+                }
+                else
+                        lJobs.append( pJob );
+        }
+
+        for( Bu::List<Job *>::iterator i = lJobs.begin(); i; i++ )
+        {
+                hJobs.enqueue( *i );
+        }
+}
+
+Bu::MiniCron::Job::Job( JobId jid, bool bRepeat ) :
+        pTimer( NULL ),
+        bContinue( bRepeat ),
+        jid( jid ),
+        tAdded( time( NULL ) ),
+        iRunCount( 0 )
+{
+}
+
+Bu::MiniCron::Job::~Job()
+{
+        delete pTimer;
+        pTimer = NULL;
+}
+
+void Bu::MiniCron::Job::run()
+{
+        iRunCount++;
+        tNextRun = pTimer->nextTime();
+        sigJob( *this );
+}
+
+time_t Bu::MiniCron::Job::getNextRun()
+{
+        return tNextRun;
+}
+
+void Bu::MiniCron::Job::calcNextRun()
+{
+        if( pTimer )
+                tNextRun = pTimer->nextTime();
+}
+
+void Bu::MiniCron::Job::setTimer( const Timer &t )
+{
+        delete pTimer;
+        pTimer = t.clone();
+}
+
+void Bu::MiniCron::Job::stop()
+{
+        bContinue = false;
+}
+
+void Bu::MiniCron::Job::resume()
+{
+        bContinue = true;
+}
+
+Bu::MiniCron::JobId Bu::MiniCron::Job::getId()
+{
+        return jid;
+}
+
+time_t Bu::MiniCron::Job::getTimeCreated()
+{
+        return tAdded;
+}
+
+int Bu::MiniCron::Job::getRunCount()
+{
+        return iRunCount;
+}
+
+Bu::MiniCron::Timer::Timer()
+{
+}
+
+Bu::MiniCron::Timer::~Timer()
+{
+}
+
+Bu::MiniCron::TimerInterval::TimerInterval( time_t tFirst, time_t tInterval ) :
+        tNext( tFirst ),
+        tInterval( tInterval )
+{
+}
+
+Bu::MiniCron::TimerInterval::~TimerInterval()
+{
+}
+
+time_t Bu::MiniCron::TimerInterval::nextTime()
+{
+        time_t tRet = tNext;
+        tNext += tInterval;
+        return tRet;
+}
+
+Bu::MiniCron::TimerBasic::TimerBasic( const Bu::FString &s ) :
+        tLast( -1 ),
+        sSpec( s )
+{
+}
+
+Bu::MiniCron::TimerBasic::~TimerBasic()
+{
+}
+
+time_t Bu::MiniCron::TimerBasic::nextTime()
+{
+        if( tLast == -1 )
+                tLast = time( NULL );
+
+        Bu::FString::const_iterator i = sSpec.begin();
+        switch( lex( i ) )
+        {
+                case tokDaily:
+                        {
+                                int iHour = lexInt( i );
+                                int iMin = lexInt( i );
+
+                                struct tm t;
+                                ::memcpy( &t, localtime( &tLast ), sizeof(struct tm) );
+                                if( iHour < t.tm_hour ||
+                                        (iHour == t.tm_hour && iMin <= t.tm_min) )
+                                {
+                                        t.tm_mday++;
+                                }
+                                t.tm_hour = iHour;
+                                t.tm_min = iMin;
+                                t.tm_sec = 0;
+                                tLast = mktime( &t );
+                        }
+                        break;
+
+                case tokHourly:
+                        {
+                                int iMin = lexInt( i );
+
+                                struct tm t;
+                                ::memcpy( &t, localtime( &tLast ), sizeof(struct tm) );
+                                if( iMin <= t.tm_min )
+                                        t.tm_hour++;
+                                t.tm_min = iMin;
+                                t.tm_sec = 0;
+                                tLast = mktime( &t );
+                        }
+                        break;
+
+                case tokWeekly:
+                        {
+                                int iDay = lexInt( i );
+                                int iHour = lexInt( i );
+                                int iMin = lexInt( i );
+                                
+                                struct tm t;
+                                ::memcpy( &t, localtime( &tLast ), sizeof(struct tm) );
+                                if( iDay < t.tm_wday || 
+                                        (iDay == t.tm_wday && iHour < t.tm_hour) ||
+                                        (iDay == t.tm_wday && iHour == t.tm_hour
+                                         && iMin <= t.tm_min) )
+                                {
+                                        if( iDay <= t.tm_wday )
+                                                t.tm_mday += 7 - (t.tm_wday-iDay);
+                                        else
+                                                t.tm_mday += 7 - (iDay-t.tm_wday);
+                                }
+                                else
+                                {
+                                        t.tm_mday += (iDay-t.tm_wday);
+                                }
+                                t.tm_hour = iHour;
+                                t.tm_min = iMin;
+                                t.tm_sec = 0;
+                                tLast = mktime( &t );
+                        }
+                        break;
+
+                case tokMonthly:
+                        break;
+
+                case tokYearly:
+                        break;
+
+                default:
+                        break;
+        }
+
+        return tLast;
+}
+
+Bu::MiniCron::TimerBasic::Token Bu::MiniCron::TimerBasic::lex(
+                Bu::FString::const_iterator &i )
+{
+        if( !i )
+        {
+                return tokEos;
+        }
+
+        Bu::FString::const_iterator b = i;
+
+        for(; b && (*b == ' ' || *b == '\t'); b++ ) { i = b+1; }
+        for(; b && *b != ' ' && *b != '\t'; b++ ) { }
+
+        Bu::FString sTok( i, b );
+        i = b;
+
+        if( sTok == "daily" )
+                return tokDaily;
+        else if( sTok == "hourly" )
+                return tokHourly;
+        else if( sTok == "weekly" )
+                return tokWeekly;
+        else if( sTok == "monthly" )
+                return tokMonthly;
+        else if( sTok == "yearly" )
+                return tokYearly;
+        else if( sTok == "sun" )
+        {
+                iVal = 0;
+                return valInt;
+        }
+        else if( sTok == "mon" )
+        {
+                iVal = 1;
+                return valInt;
+        }
+        else if( sTok == "tue" )
+        {
+                iVal = 2;
+                return valInt;
+        }
+        else if( sTok == "wed" )
+        {
+                iVal = 3;
+                return valInt;
+        }
+        else if( sTok == "thu" )
+        {
+                iVal = 4;
+                return valInt;
+        }
+        else if( sTok == "fri" )
+        {
+                iVal = 5;
+                return valInt;
+        }
+        else if( sTok == "sat" )
+        {
+                iVal = 6;
+                return valInt;
+        }
+        else if( sTok[0] >= '0' && sTok[0] <= '9' )
+        {
+                iVal = strtol( sTok.getStr(), NULL, 0 );
+                return valInt;
+        }
+
+        return tokErr;
+}
+
+int Bu::MiniCron::TimerBasic::lexInt( Bu::FString::const_iterator &i )
+{
+        Token t = lex( i );
+        if( t == tokEos )
+                return 0;
+        if( t != valInt )
+                throw Bu::ExceptionBase("Expected int, got something else.");
+        return iVal;
+}
+
diff --git a/src/minicron.h b/src/minicron.h
new file mode 100644
index 0000000..b100ad0
--- /dev/null
+++ b/src/minicron.h
@@ -0,0 +1,226 @@
+#ifndef BU_MINICRON_H
+#define BU_MINICRON_H
+
+#include "bu/signals.h"
+#include "bu/heap.h"
+#include "bu/fstring.h"
+
+#include <time.h>
+
+namespace Bu
+{
+        /**
+         * A simple cron like system designed to be embedded in any program.  This
+         * class creates a simple cron system that can run any number of jobs at
+         * customizable intervals or schedules.  It does not support some of the
+         * more complex scheduling that some cron systems can do such as load
+         * balancing directly, but this could be done on the job side.
+         *
+         * This system is synchronous, it does not use any threads on it's own, but
+         * it is threadsafe, so a cron thread could be created if desired.
+         *
+         * The operation is fairly simple, jobs can be added at any time, and use
+         * any timer they would like, even custom timers.  When it is time for a
+         * job to be run it signals the slot provided when the job was added.  Every
+         * job slot recieves a handle to the job object so that it may control it's
+         * own lifetime and get information about itself.  In addition, every job
+         * is assigned a unique ID that can be used to control it's operation
+         * at any time.
+         *
+         * By default a job will continually reschedule itself after being run
+         * unless it calls stop() on it's job object, it is removed using
+         * removeJob() on the cron object, or it is added with addJobOnce.
+         */
+        class MiniCron
+        {
+        public:
+                class Job;
+                class Timer;
+                typedef Bu::Signal1<void, Bu::MiniCron::Job &> CronSignal;
+                typedef int JobId;
+
+                MiniCron();
+                virtual ~MiniCron();
+
+                /**
+                 * Tells you if there are jobs registered in the MiniCron.
+                 *@returns true if there are jobs, false otherwise.
+                 */
+                virtual bool hasJobs();
+
+                /**
+                 * If there are jobs, tells you the time the next one will execute.
+                 *@returns The timestamp that the next job will execute at.
+                 */
+                virtual time_t getNextRun();
+
+                /**
+                 * Call this regularly to execute all jobs that should be executed.
+                 * This will loop until all jobs who's run time match the current time
+                 * or are below the current time (we've missed them).
+                 * If there is nothing to run, the runtime of this funcion is constant,
+                 * it is very fast.  Otherwise it executes at log(N) per job run,
+                 * O(N*log(N)).
+                 */
+                virtual void poll();
+
+                /**
+                 * Add a job for repeated scheduling.  Pass in a slot to signal, and a
+                 * Timer object to use to do the scheduling.  This function returns a
+                 * JobId which can be used at a later time to control the execution of
+                 * the job.
+                 */
+                virtual JobId addJob( CronSignal sigJob, const Timer &t );
+
+                /**
+                 * Add a job for one time scheduling.  Pass in a slot to signal, and a
+                 * Timer object to use to schodule the one run of this job.  This
+                 * function returns a JobId which can be used at a later time to control
+                 * the execution of the job.
+                 */
+                virtual JobId addJobOnce( CronSignal sigJob, const Timer &t );
+
+                /**
+                 * Remove a job, preventing all future runs of the job.  If there is no
+                 * job matching the given JobId then nothing will happen.  However, this
+                 * function is relatively expensive compared to the others in this class
+                 * and has a worse case runtime of 2*N*log(N), still not that bad, and
+                 * a O(N*log(N)).
+                 */
+                virtual void removeJob( JobId jid );
+
+                class Timer
+                {
+                public:
+                        Timer();
+                        virtual ~Timer();
+
+                        virtual time_t nextTime()=0;
+                        virtual Timer *clone() const = 0;
+                };
+
+                class TimerInterval : public Timer
+                {
+                public:
+                        TimerInterval( time_t tFirst, time_t tInterval );
+                        virtual ~TimerInterval();
+
+                        virtual time_t nextTime();
+                        virtual Timer *clone() const
+                                { return new TimerInterval( *this ); }
+                private:
+                        time_t tNext;
+                        time_t tInterval;
+                };
+
+                class TimerBasic : public Timer
+                {
+                public:
+                        TimerBasic( const Bu::FString &s );
+                        virtual ~TimerBasic();
+
+                        virtual time_t nextTime();
+                        virtual Timer *clone() const
+                                { return new TimerBasic( *this ); }
+
+                private:
+                        enum Token
+                        {
+                                tokDaily,
+                                tokHourly,
+                                tokWeekly,
+                                tokMonthly,
+                                tokYearly,
+                                valInt,
+                                tokErr,
+                                tokEos
+                        };
+                        Token lex( Bu::FString::const_iterator &i );
+                        int lexInt( Bu::FString::const_iterator &i );
+                        int iVal; //< A temp variable for parsing.
+                        time_t tLast;
+                        Bu::FString sSpec;
+                };
+                
+                class Job
+                {
+                        friend class Bu::MiniCron;
+                public:
+                        Job( JobId jid, bool bRepeat=true );
+                        virtual ~Job();
+
+                        /**
+                         * Execute this job once, increment the runcount and schedule the
+                         * next occurance of it.
+                         */
+                        void run();
+
+                        /**
+                         * Get the time this job will next run.
+                         */
+                        time_t getNextRun();
+
+                        /**
+                         * Compute the time this job will next run.
+                         */
+                        void calcNextRun();
+
+                        /**
+                         * Replace the current job timer with a new one, this will trigger
+                         * a re-schedule.
+                         */
+                        void setTimer( const Timer &t );
+
+                        /**
+                         * Stop execution of this job, never execute this job again.
+                         */
+                        void stop();
+
+                        /**
+                         * Undo a previous stop.  This will cause a job that has been
+                         * stopped or even added with addJobOnce to be set for repeated
+                         * scheduling.
+                         */
+                        void resume();
+
+                        /**
+                         * Get the unique ID of this job.
+                         */
+                        JobId getId();
+
+                        /**
+                         * Get the timestamp this job was created.
+                         */
+                        time_t getTimeCreated();
+
+                        /**
+                         * Get the current run count of this job, how many times it has been
+                         * executed.  This is incremented before the slot is signaled.
+                         */
+                        int getRunCount();
+
+                private:
+                        CronSignal sigJob;
+                        time_t tNextRun;
+                        Timer *pTimer;
+                        bool bContinue;
+                        JobId jid;
+                        time_t tAdded;
+                        int iRunCount;
+                };
+
+        private:
+                struct JobPtrCmp
+                {
+                        bool operator()( const Job *pLeft, const Job *pRight )
+                        {
+                                return pLeft->tNextRun < pRight->tNextRun;
+                        }
+                };
+                typedef Bu::Heap<Job *, JobPtrCmp> JobHeap;
+                JobHeap hJobs;
+                JobId jidNext;
+        };
+};
+
+#endif
diff --git a/src/tests/minicron.cpp b/src/tests/minicron.cpp
new file mode 100644
index 0000000..715a74d
--- /dev/null
+++ b/src/tests/minicron.cpp
@@ -0,0 +1,53 @@
+#include "bu/minicron.h"
+#include "bu/sio.h"
+
+#include <unistd.h>
+
+using namespace Bu;
+        
+Bu::MiniCron mCron;
+
+void job0( Bu::MiniCron::Job &job )
+{
+        sio << time( NULL ) << ": job0( id = " << job.getId() << ", count = "
+                << job.getRunCount() << ")" << sio.nl;
+}
+
+void job1( Bu::MiniCron::Job &job )
+{
+        sio << time( NULL ) << ": job1( id = " << job.getId() << ", count = "
+                << job.getRunCount() << ")" << sio.nl;
+        mCron.removeJob( 4 );
+}
+
+void job2( Bu::MiniCron::Job &job )
+{
+        sio << time( NULL ) << ": job2( id = " << job.getId() << ", count = "
+                << job.getRunCount() << ")" << sio.nl;
+}
+
+void job3( Bu::MiniCron::Job &job )
+{
+        sio << time( NULL ) << ": job3( id = " << job.getId() << ", count = "
+                << job.getRunCount() << ")" << sio.nl;
+}
+
+int main()
+{
+
+        mCron.addJob( slot( &job0 ), MiniCron::TimerInterval( time(NULL)+3, 5 ) );
+        mCron.addJob( slot( &job1 ), MiniCron::TimerInterval( time(NULL)+10, 8 ) );
+        mCron.addJob( slot( &job2 ), MiniCron::TimerBasic("weekly wed 17") );
+        mCron.addJob( slot( &job3 ), MiniCron::TimerInterval( time(NULL)+1, 2 ) );
+
+        sio << time( NULL ) << ": Program started." << sio.nl;
+
+        for(;;)
+        {
+                usleep( 50000 );
+                mCron.poll();
+        }
+
+        return 0;
+}
+