Tasks: only execute the event if the plugin is interested in it

src/lib/Hydra/Event/BuildFinished.pm

@@ -27,6 +27,11 @@ sub new {
     }, $self;
 }
 
+sub interestedIn {
+    my ($self, $plugin) = @_;
+    return int(defined($plugin->can('buildFinished')));
+}
+
 sub load {
     my ($self, $db) = @_;
 

src/lib/Hydra/Event/BuildQueued.pm

@@ -25,6 +25,11 @@ sub new {
     }, $self;
 }
 
+sub interestedIn {
+    my ($self, $plugin) = @_;
+    return int(defined($plugin->can('buildQueued')));
+}
+
 sub load {
     my ($self, $db) = @_;
 

src/lib/Hydra/Event/BuildStarted.pm

@@ -25,6 +25,11 @@ sub new {
     }, $self;
 }
 
+sub interestedIn {
+    my ($self, $plugin) = @_;
+    return int(defined($plugin->can('buildStarted')));
+}
+
 sub load {
     my ($self, $db) = @_;
 

src/lib/Hydra/Event/StepFinished.pm

@@ -34,6 +34,11 @@ sub new :prototype($$$) {
     }, $self;
 }
 
+sub interestedIn {
+    my ($self, $plugin) = @_;
+    return int(defined($plugin->can('stepFinished')));
+}
+
 sub load {
     my ($self, $db) = @_;