From 36d2781d9f4890dda54419d38679d2da3d04b7bd Mon Sep 17 00:00:00 2001
From: Davin McCall <davmac@davmac.org>
Date: Sun, 19 Mar 2017 14:12:51 +0000
Subject: [PATCH] Release soft dependencies if they stop early.

---
 src/service.cc | 28 +++++++++++++++++++++-------
 src/service.h  |  4 +++-
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/src/service.cc b/src/service.cc
index bc0e8a7..258e0e8 100644
--- a/src/service.cc
+++ b/src/service.cc
@@ -86,6 +86,16 @@ void ServiceRecord::stopped() noexcept
         }
     }
     
+    // If we are a soft dependency of another target, break the acquisition from that target now:
+    if (! will_restart) {
+        for (auto dependency : soft_dpts) {
+            if (dependency->holding_acq) {
+                dependency->holding_acq = false;
+                release();
+            }
+        }
+    }
+    
     if (will_restart) {
         // Desired state is "started".
         service_set->addToStartQueue(this);
@@ -337,7 +347,10 @@ void ServiceRecord::release_dependencies() noexcept
 
     for (auto i = soft_deps.begin(); i != soft_deps.end(); ++i) {
         ServiceRecord * to = i->getTo();
-        to->release();
+        if (i->holding_acq) {
+            to->release();
+            i->holding_acq = false;
+        }
     }
     
     service_set->service_inactive(this);
@@ -352,11 +365,6 @@ void ServiceRecord::start(bool activate) noexcept
     
     if (desired_state == ServiceState::STARTED && service_state != ServiceState::STOPPED) return;
     
-    if (required_by == 0) {
-        // It really doesn't make any sense to start if there is no dependent or explicit activation.
-        return;
-    }
-
     desired_state = ServiceState::STARTED;
     service_set->addToStartQueue(this);
 }
@@ -372,6 +380,7 @@ void ServiceRecord::do_propagation() noexcept
         for (auto i = soft_deps.begin(); i != soft_deps.end(); ++i) {
             ServiceRecord * to = i->getTo();
             to->require();
+            i->holding_acq = true;
         }
         
         prop_require = false;
@@ -697,7 +706,12 @@ void ServiceRecord::failed_to_start(bool depfailed) noexcept
     for (auto i = soft_dpts.begin(); i != soft_dpts.end(); i++) {
         // We can send 'start', because this is only a soft dependency.
         // Our startup failure means that they don't have to wait for us.
-        (*i)->getFrom()->dependencyStarted();
+        if ((*i)->waiting_on) {
+            (*i)->holding_acq = false;
+            (*i)->waiting_on = false;
+            (*i)->getFrom()->dependencyStarted();
+            release();
+        }
     }
 }
 
diff --git a/src/service.h b/src/service.h
index fa9b16a..3b58e90 100644
--- a/src/service.h
+++ b/src/service.h
@@ -143,8 +143,10 @@ class ServiceDep
     public:
     /* Whether the 'from' service is waiting for the 'to' service to start */
     bool waiting_on;
+    /* Whether the 'from' service is holding an acquire on the 'to' service */
+    bool holding_acq;
 
-    ServiceDep(ServiceRecord * from, ServiceRecord * to) noexcept : from(from), to(to), waiting_on(false)
+    ServiceDep(ServiceRecord * from, ServiceRecord * to) noexcept : from(from), to(to), waiting_on(false), holding_acq(false)
     {  }
 
     ServiceRecord * getFrom() noexcept
-- 
2.25.1