From ba757809d0facb1bcbcfdf15e6b418daa2fd7b36 Mon Sep 17 00:00:00 2001
From: Michael Carlberg <c@rlberg.se>
Date: Fri, 23 Dec 2016 05:19:45 +0100
Subject: [PATCH] refactor(modules): Defer cache rebuild

---
 include/modules/meta/base.hpp |  3 ++-
 include/modules/meta/base.inl | 11 ++++++-----
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/include/modules/meta/base.hpp b/include/modules/meta/base.hpp
index 7dffb169..0aa82690 100644
--- a/include/modules/meta/base.hpp
+++ b/include/modules/meta/base.hpp
@@ -153,7 +153,8 @@ namespace modules {
     thread m_mainthread;
 
    private:
-    stateflag m_enabled{true};
+    atomic<bool> m_enabled{true};
+    atomic<bool> m_changed{true};
     string m_cache;
   };
 
diff --git a/include/modules/meta/base.inl b/include/modules/meta/base.inl
index 217c93cf..9c0c6d62 100644
--- a/include/modules/meta/base.inl
+++ b/include/modules/meta/base.inl
@@ -77,6 +77,11 @@ namespace modules {
 
   template <typename Impl>
   string module<Impl>::contents() {
+    if (m_changed) {
+      m_log.info("Rebuilding cache for '%s'...", name());
+      m_cache = CAST_MOD(Impl)->get_output();
+      m_changed = false;
+    }
     return m_cache;
   }
 
@@ -85,11 +90,7 @@ namespace modules {
 
   template <typename Impl>
   void module<Impl>::broadcast() {
-    if (!running()) {
-      return;
-    }
-
-    m_cache = CAST_MOD(Impl)->get_output();
+    m_changed = true;
     m_sig.emit(sig_ev::process_broadcast{});
   }