Service API V2: Add methods for webapp setup to control backend

- Add SchedulingEnabled to Myth/GetBackendInfo response
- Add Myth/Shutdown method with Restart option.
- Add Myth/ManageScheduler method to enable or disable scheduler

mythtv/programs/mythbackend/mythbackend.cpp

@@ -153,6 +153,16 @@ int main(int argc, char **argv)
 
     gCoreContext->SetAsBackend(true);
     retval = run_backend(cmdline);
+    // Retcode 256 is a special value to signal to mythbackend to restart
+    // This is used by the V2Myth/Shutdown?Restart=true API call
+    if (retval == 258) {
+        LOG(VB_GENERAL, LOG_INFO,
+            QString("Restarting mythbackend"));
+        usleep(50000);
+        int rc = execvp(argv[0], argv);
+        LOG(VB_GENERAL, LOG_ERR,
+            QString("execvp failed prog %1 rc=%2 errno=%3").arg(argv[0]).arg(rc).arg(errno));
+    }
     return retval;
 }
 

mythtv/programs/mythbackend/scheduler.h

@@ -108,6 +108,7 @@ class Scheduler : public MThread, public MythScheduler
 
     void DisableScheduling(void) { m_schedulingEnabled = false; }
     void EnableScheduling(void) { m_schedulingEnabled = true; }
+    bool QueryScheduling(void) { return m_schedulingEnabled; }
     void GetNextLiveTVDir(uint cardid);
     void ResetIdleTime(void);
 

mythtv/programs/mythbackend/servicesv2/v2envInfo.h

@@ -25,6 +25,7 @@ class V2EnvInfo : public QObject
     SERVICE_PROPERTY2( QString, HOME        )
     SERVICE_PROPERTY2( QString, USER        )
     SERVICE_PROPERTY2( QString, MYTHCONFDIR );
+    SERVICE_PROPERTY2( bool,    SchedulingEnabled );
 
     public:
 
@@ -34,7 +35,8 @@ class V2EnvInfo : public QObject
               m_LCALL       ( ""     ),
               m_LCCTYPE     ( ""     ),
               m_HOME        ( ""     ),
-              m_MYTHCONFDIR ( ""     )
+              m_MYTHCONFDIR ( ""     ),
+              m_SchedulingEnabled (false)
         {
         }
 
@@ -46,6 +48,7 @@ class V2EnvInfo : public QObject
             m_HOME        = src->m_HOME;
             m_USER        = src->m_USER;
             m_MYTHCONFDIR = src->m_MYTHCONFDIR;
+            m_SchedulingEnabled = src->m_SchedulingEnabled;
         }
 
     private:

mythtv/programs/mythbackend/servicesv2/v2myth.cpp

@@ -1113,6 +1113,9 @@ V2BackendInfo* V2Myth::GetBackendInfo( void )
     pEnv->setUSER          ( qEnvironmentVariable("USER",
                              qEnvironmentVariable("USERNAME"))   );
     pEnv->setMYTHCONFDIR   ( qEnvironmentVariable("MYTHCONFDIR") );
+    auto *scheduler = dynamic_cast<Scheduler*>(gCoreContext->GetScheduler());
+    if (scheduler != nullptr)
+        pEnv->setSchedulingEnabled(scheduler->QueryScheduling());
     // This needs to be first assigned to a new QString because setLogArgs
     // uses a std_move which clears out the source variable while setting.
     QString logArgs = logPropagateArgs;
@@ -1219,3 +1222,31 @@ bool V2Myth::ManageUrlProtection( const QString &sServices,
     return gCoreContext->SaveSettingOnHost("HTTP/Protected/Urls",
                                            protectedURLs.join(';'), "");
 }
+
+bool V2Myth::ManageScheduler ( bool Enable, bool Disable )
+{
+    auto *scheduler = dynamic_cast<Scheduler*>(gCoreContext->GetScheduler());
+    if (scheduler == nullptr)
+        throw QString("Scheduler is null");
+    // onle and only one of enable and disable must be supplied
+    if (Enable == Disable)
+        return false;
+    if (Enable)
+        scheduler->EnableScheduling();
+    if (Disable)
+        scheduler->DisableScheduling();
+    return true;
+}
+
+bool V2Myth::Shutdown ( int Retcode, bool Restart )
+{
+    if (Retcode < 0 || Retcode > 255)
+        return false;
+    if (Restart)
+        // Retcode 258 is a special value to signal to mythbackend to restart
+        // This is designed so that if the execvp fails it will give return code of 2,
+        // indicating failure and maybe causing the service module to restart.
+        Retcode = 258;
+    QCoreApplication::exit(Retcode);
+    return true;
+}

mythtv/programs/mythbackend/servicesv2/v2myth.h

@@ -46,6 +46,8 @@ class V2Myth : public MythHTTPService
     Q_CLASSINFO( "ManageDigestUser",      "methods=POST"                )
     Q_CLASSINFO( "ManageUrlProtection",   "methods=POST"                )
     Q_CLASSINFO( "SetConnectionInfo",     "methods=POST"                )
+    Q_CLASSINFO("ManageScheduler",        "methods=POST")
+    Q_CLASSINFO("Shutdown",               "methods=POST")
 
 
   public:
@@ -177,6 +179,11 @@ class V2Myth : public MythHTTPService
     static bool         ManageUrlProtection ( const QString &Services,
                                               const QString &AdminPassword );
 
+    static bool         ManageScheduler    ( bool Enable,
+                                              bool Disable );
+
+    static bool         Shutdown    ( int Retcode, bool Restart);
+
   private:
     Q_DISABLE_COPY(V2Myth)