From 560e522457ecb643acef5a55a982e10b365ba620 Mon Sep 17 00:00:00 2001
From: Justin Viiret <justin.viiret@intel.com>
Date: Tue, 21 Mar 2017 10:58:26 +1100
Subject: [PATCH] ng_calc_components: add Grey box control

---
 src/grey.cpp                        |  2 ++
 src/grey.h                          |  1 +
 src/nfagraph/ng.cpp                 |  4 ++--
 src/nfagraph/ng_calc_components.cpp | 14 ++++++++++----
 src/nfagraph/ng_calc_components.h   |  6 ++++--
 unit/internal/nfagraph_comp.cpp     | 12 +++++++++---
 6 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/src/grey.cpp b/src/grey.cpp
index ea92fdb5..24140c05 100644
--- a/src/grey.cpp
+++ b/src/grey.cpp
@@ -42,6 +42,7 @@ namespace ue2 {
 
 Grey::Grey(void) :
                    optimiseComponentTree(true),
+                   calcComponents(true),
                    performGraphSimplification(true),
                    prefilterReductions(true),
                    removeEdgeRedundancy(true),
@@ -209,6 +210,7 @@ void applyGreyOverrides(Grey *g, const string &s) {
         } while (0)
 
         G_UPDATE(optimiseComponentTree);
+        G_UPDATE(calcComponents);
         G_UPDATE(performGraphSimplification);
         G_UPDATE(prefilterReductions);
         G_UPDATE(removeEdgeRedundancy);
diff --git a/src/grey.h b/src/grey.h
index 5fde7b4b..50519418 100644
--- a/src/grey.h
+++ b/src/grey.h
@@ -41,6 +41,7 @@ struct Grey {
 
     bool optimiseComponentTree;
 
+    bool calcComponents;
     bool performGraphSimplification;
     bool prefilterReductions;
     bool removeEdgeRedundancy;
diff --git a/src/nfagraph/ng.cpp b/src/nfagraph/ng.cpp
index bdd767e9..dc74dcee 100644
--- a/src/nfagraph/ng.cpp
+++ b/src/nfagraph/ng.cpp
@@ -437,7 +437,7 @@ bool NG::addGraph(ExpressionInfo &expr, unique_ptr<NGHolder> g_ptr) {
     // Split the graph into a set of connected components and process those.
     // Note: this invalidates g_ptr.
 
-    auto g_comp = calcComponents(std::move(g_ptr));
+    auto g_comp = calcComponents(std::move(g_ptr), cc.grey);
     assert(!g_comp.empty());
 
     if (!som) {
@@ -446,7 +446,7 @@ bool NG::addGraph(ExpressionInfo &expr, unique_ptr<NGHolder> g_ptr) {
             reformLeadingDots(*gc);
         }
 
-        recalcComponents(g_comp);
+        recalcComponents(g_comp, cc.grey);
     }
 
     if (processComponents(*this, expr, g_comp, som)) {
diff --git a/src/nfagraph/ng_calc_components.cpp b/src/nfagraph/ng_calc_components.cpp
index ff0d0fe1..2c1dbcdb 100644
--- a/src/nfagraph/ng_calc_components.cpp
+++ b/src/nfagraph/ng_calc_components.cpp
@@ -55,6 +55,7 @@
 #include "ng_prune.h"
 #include "ng_undirected.h"
 #include "ng_util.h"
+#include "grey.h"
 #include "ue2common.h"
 #include "util/graph_range.h"
 #include "util/make_unique.h"
@@ -376,12 +377,13 @@ void splitIntoComponents(unique_ptr<NGHolder> g,
                   }));
 }
 
-deque<unique_ptr<NGHolder>> calcComponents(unique_ptr<NGHolder> g) {
+deque<unique_ptr<NGHolder>> calcComponents(unique_ptr<NGHolder> g,
+                                           const Grey &grey) {
     deque<unique_ptr<NGHolder>> comps;
 
     // For trivial cases, we needn't bother running the full
     // connected_components algorithm.
-    if (isAlternationOfClasses(*g)) {
+    if (!grey.calcComponents || isAlternationOfClasses(*g)) {
         comps.push_back(std::move(g));
         return comps;
     }
@@ -402,7 +404,11 @@ deque<unique_ptr<NGHolder>> calcComponents(unique_ptr<NGHolder> g) {
     return comps;
 }
 
-void recalcComponents(deque<unique_ptr<NGHolder>> &comps) {
+void recalcComponents(deque<unique_ptr<NGHolder>> &comps, const Grey &grey) {
+    if (!grey.calcComponents) {
+        return;
+    }
+
     deque<unique_ptr<NGHolder>> out;
 
     for (auto &gc : comps) {
@@ -415,7 +421,7 @@ void recalcComponents(deque<unique_ptr<NGHolder>> &comps) {
             continue;
         }
 
-        auto gc_comps = calcComponents(std::move(gc));
+        auto gc_comps = calcComponents(std::move(gc), grey);
         out.insert(end(out), std::make_move_iterator(begin(gc_comps)),
                    std::make_move_iterator(end(gc_comps)));
     }
diff --git a/src/nfagraph/ng_calc_components.h b/src/nfagraph/ng_calc_components.h
index 0359f4a0..1bcdc5f8 100644
--- a/src/nfagraph/ng_calc_components.h
+++ b/src/nfagraph/ng_calc_components.h
@@ -39,13 +39,15 @@
 namespace ue2 {
 
 class NGHolder;
+struct Grey;
 
 bool isAlternationOfClasses(const NGHolder &g);
 
 std::deque<std::unique_ptr<NGHolder>>
-calcComponents(std::unique_ptr<NGHolder> g);
+calcComponents(std::unique_ptr<NGHolder> g, const Grey &grey);
 
-void recalcComponents(std::deque<std::unique_ptr<NGHolder>> &comps);
+void recalcComponents(std::deque<std::unique_ptr<NGHolder>> &comps,
+                      const Grey &grey);
 
 } // namespace ue2
 
diff --git a/unit/internal/nfagraph_comp.cpp b/unit/internal/nfagraph_comp.cpp
index 8aae9519..61b05a46 100644
--- a/unit/internal/nfagraph_comp.cpp
+++ b/unit/internal/nfagraph_comp.cpp
@@ -43,7 +43,9 @@ TEST(NFAGraph, CalcComp1) {
     auto graph = constructGraph("abc|def|ghi", 0);
     ASSERT_TRUE(graph != nullptr);
 
-    auto comps = calcComponents(std::move(graph));
+    Grey grey;
+    grey.calcComponents = true;
+    auto comps = calcComponents(std::move(graph), grey);
     ASSERT_EQ(3, comps.size());
 }
 
@@ -51,7 +53,9 @@ TEST(NFAGraph, CalcComp2) {
     auto graph = constructGraph("a|b|c|d|e|f|g|h|i", 0);
     ASSERT_TRUE(graph != nullptr);
 
-    auto comps = calcComponents(std::move(graph));
+    Grey grey;
+    grey.calcComponents = true;
+    auto comps = calcComponents(std::move(graph), grey);
 
     // We should be identifying this as a trivial case and not splitting it.
     ASSERT_EQ(1, comps.size());
@@ -62,7 +66,9 @@ TEST(NFAGraph, RecalcComp1) {
     comps.push_back(constructGraph("abc|def|ghi", 0));
     ASSERT_TRUE(comps.back() != nullptr);
 
-    recalcComponents(comps);
+    Grey grey;
+    grey.calcComponents = true;
+    recalcComponents(comps, grey);
 
     ASSERT_EQ(3, comps.size());
 }