From 0c1172b17d68cccd19c7551916857fe8ae9ac092 Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <hillbrand@ucdavis.edu>
Date: Tue, 15 May 2018 15:50:59 -0700
Subject: [PATCH] Garbage collection optimization

We only need to iterate over the anchors when there are items that are
marked invalid.  We check once in the item list and only if there are
invalid items to remove do we trim the anchor lists.

However, the connected items might still need to be trimmed, so we leave
this final step outside of the conditional.
---
 pcbnew/connectivity_algo.cpp | 45 +++++++++++++++++++++---------------
 1 file changed, 26 insertions(+), 19 deletions(-)

diff --git a/pcbnew/connectivity_algo.cpp b/pcbnew/connectivity_algo.cpp
index 29e650acd4..bb5b66bcb7 100644
--- a/pcbnew/connectivity_algo.cpp
+++ b/pcbnew/connectivity_algo.cpp
@@ -443,6 +443,9 @@ void CN_CONNECTIVITY_ALGO::searchConnections( bool aIncludeZones )
     printf("Search start\n");
 #endif
 
+#ifdef PROFILE
+    PROF_COUNTER garbage_collection( "garbage-collection" );
+#endif
     std::vector<CN_ITEM*> garbage;
     garbage.reserve( 1024 );
 
@@ -471,10 +474,10 @@ void CN_CONNECTIVITY_ALGO::searchConnections( bool aIncludeZones )
     #endif
 
 #ifdef PROFILE
+    garbage_collection.Show();
     PROF_COUNTER search_cnt( "search-connections" );
     PROF_COUNTER search_basic( "search-basic" );
     PROF_COUNTER search_pads( "search-pads" );
-    PROF_COUNTER search_tracks( "search-tracks" );
 #endif
 
     if( m_padList.IsDirty() || m_trackList.IsDirty() || m_viaList.IsDirty() )
@@ -492,6 +495,7 @@ void CN_CONNECTIVITY_ALGO::searchConnections( bool aIncludeZones )
         }
 #ifdef PROFILE
         search_pads.Show();
+        PROF_COUNTER search_tracks( "search-tracks" );
 #endif
 
         for( auto& trackItem : m_trackList )
@@ -604,23 +608,8 @@ void CN_ITEM::RemoveInvalidRefs()
 
 void CN_LIST::RemoveInvalidItems( std::vector<CN_ITEM*>& aGarbage )
 {
-    auto lastAnchor = std::remove_if(m_anchors.begin(), m_anchors.end(),
-        [] ( const CN_ANCHOR_PTR anchor ) {
-            return !anchor->Valid();
-        } );
-
-    m_anchors.resize( lastAnchor - m_anchors.begin() );
-    for( auto i = 0; i < PCB_LAYER_ID_COUNT; i++ )
+    auto lastItem = std::remove_if(m_items.begin(), m_items.end(), [&aGarbage] ( CN_ITEM* item )
     {
-        lastAnchor = std::remove_if(m_layer_anchors[i].begin(), m_layer_anchors[i].end(),
-                [] ( const CN_ANCHOR_PTR anchor ) {
-                    return !anchor->Valid();
-                } );
-
-        m_layer_anchors[i].resize( lastAnchor - m_layer_anchors[i].begin() );
-    }
-
-    auto lastItem = std::remove_if(m_items.begin(), m_items.end(), [&aGarbage] ( CN_ITEM* item ) {
         if( !item->Valid() )
         {
             aGarbage.push_back ( item );
@@ -630,10 +619,28 @@ void CN_LIST::RemoveInvalidItems( std::vector<CN_ITEM*>& aGarbage )
         return false;
     } );
 
-    m_items.resize( lastItem - m_items.begin() );
+    if( lastItem != m_items.end())
+    {
+        auto lastAnchor = std::remove_if(m_anchors.begin(), m_anchors.end(),
+            [] ( const CN_ANCHOR_PTR anchor ) {
+                return !anchor->Valid();
+            } );
+
+        m_anchors.resize( lastAnchor - m_anchors.begin() );
+        for( auto i = 0; i < PCB_LAYER_ID_COUNT; i++ )
+        {
+            lastAnchor = std::remove_if(m_layer_anchors[i].begin(), m_layer_anchors[i].end(),
+                    [] ( const CN_ANCHOR_PTR anchor ) {
+                        return !anchor->Valid();
+                    } );
+
+            m_layer_anchors[i].resize( lastAnchor - m_layer_anchors[i].begin() );
+        }
+
+        m_items.resize( lastItem - m_items.begin() );
+    }
 
     // fixme: mem leaks
-
     for( auto item : m_items )
         item->RemoveInvalidRefs();
 }