From 196696a8d01c83a81f5a282e6d65bf5302515f0a Mon Sep 17 00:00:00 2001
From: Ichthyostega <prg@ichthyostega.de>
Date: Wed, 21 Dec 2016 03:56:56 +0100
Subject: [PATCH] Looper: draft possible implementation

seemingly a quite simple "trap door" mechanism is sufficient
---
 src/proc/control/looper.hpp                   | 21 ++++++++++++++-----
 src/proc/control/proc-dispatcher.cpp          |  7 +------
 .../proc/control/dispatcher-looper-test.cpp   |  2 ++
 3 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/src/proc/control/looper.hpp b/src/proc/control/looper.hpp
index 3f03669c6..7a73ee9e8 100644
--- a/src/proc/control/looper.hpp
+++ b/src/proc/control/looper.hpp
@@ -82,6 +82,7 @@ namespace control {
       
       bool shutdown_ = false;
       bool disabled_ = false;
+      uint dirty_    = false;
       Predicate hasCommandsPending_;
         
     public:
@@ -98,7 +99,7 @@ namespace control {
       bool isDying()    const  { return shutdown_; }
       bool isDisabled() const  { return disabled_ or isDying(); }
       bool isWorking()  const  { return hasCommandsPending_() and not isDisabled(); }
-      bool runBuild()   const  { return false; }
+      bool runBuild()   const  { return (dirty_ and not hasCommandsPending_()) or forceBuild(); }
       bool isIdle()     const  { return not (isWorking() or runBuild() or isDisabled()); }
       
       
@@ -118,12 +119,14 @@ namespace control {
       
       /** invoking this function signals
        *  that all consequences of past state changes
-       *  have been processed and duly resolved.
+       *  have been processed and are duly resolved.
        */
       void
       markStateProcessed()
         {
-          UNIMPLEMENTED("state transition logic");
+          if (runBuild())
+            --dirty_;
+          ENSURE (dirty_ <= 2);
         }
       
       bool
@@ -136,8 +139,11 @@ namespace control {
       bool
       requireAction()
         {
+          if (isWorking())
+            dirty_ = 2;
+          
           return isWorking()
-              or runBuild()
+              or forceBuild()
               or isDying();
         }
       
@@ -162,6 +168,11 @@ namespace control {
       
     private:
       static uint establishWakeTimeout();
+      
+      bool forceBuild()  const
+        {
+          return false;
+        }
     };
   ////////////////TODO 12/16 currently just fleshing  out the API....
   
@@ -177,7 +188,7 @@ namespace control {
    * period visible to the user as update response delay within the UI.
    * @todo find a way how to retrieve this value from application config!    ////////////////////TICKET #1052 : access application configuration
    */
-  uint
+  uint inline
   Looper::establishWakeTimeout()
   {
     return PROC_DISPATCHER_BUILDER_DELAY_ms;
diff --git a/src/proc/control/proc-dispatcher.cpp b/src/proc/control/proc-dispatcher.cpp
index fe003036f..39dd4ae65 100644
--- a/src/proc/control/proc-dispatcher.cpp
+++ b/src/proc/control/proc-dispatcher.cpp
@@ -47,12 +47,8 @@
 #include "proc/control/session-command-service.hpp"
 #include "proc/mobject/session.hpp"
 #include "backend/thread-wrapper.hpp"
-//#include "proc/mobject/mobject-ref.hpp"
-//#include "proc/mobject/mobject.hpp"
-//#include "proc/mobject/placement.hpp"
 
 #include <memory>
-//using boost::str;
   
 using backend::ThreadJoinable;
 using lib::Sync;
@@ -71,7 +67,6 @@ namespace control {
     {
       bool canDispatch_{false};
       bool blocked_    {false};
-      bool mustHalt_   {false};  /////////////////TODO this flag shall be relocated into the Looper!
       
       unique_ptr<SessionCommandService> commandService_;
       
@@ -146,7 +141,7 @@ namespace control {
         {
           Lock sync(this);
           commandService_.reset(); // closes Session interface
-          mustHalt_ = true;
+          looper_.triggerShutdown();
           UNIMPLEMENTED("*must* notify loop thread");  /////////////////TODO really?  YES!!!
           //////////////////////////////////////////TODO notify!!!!
         }
diff --git a/tests/core/proc/control/dispatcher-looper-test.cpp b/tests/core/proc/control/dispatcher-looper-test.cpp
index 3f23b7146..31ed3392c 100644
--- a/tests/core/proc/control/dispatcher-looper-test.cpp
+++ b/tests/core/proc/control/dispatcher-looper-test.cpp
@@ -168,6 +168,8 @@ namespace test    {
           CHECK (looper.shallLoop());
           
           setup.has_commands_in_queue = false;
+          looper.markStateProcessed();
+          looper.markStateProcessed();
           
           CHECK (not looper.requireAction());
           CHECK (not looper.isWorking());