ng_calc_components: add Grey box control

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);

src/grey.h

@@ -41,6 +41,7 @@ struct Grey {
 
     bool optimiseComponentTree;
 
+    bool calcComponents;
     bool performGraphSimplification;
     bool prefilterReductions;
     bool removeEdgeRedundancy;

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)) {

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)));
     }

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