From ba0420cba278797804cb585149819fa2b7c9de2d Mon Sep 17 00:00:00 2001
From: johnfxgalea <jgoffice342@gmail.com>
Date: Sun, 30 May 2021 20:22:25 +0100
Subject: [PATCH 1/2] Add for_each_predecessor() to grapht

---
 src/util/graph.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/util/graph.h b/src/util/graph.h
index e5277ada414..9b9f6b6a5e8 100644
--- a/src/util/graph.h
+++ b/src/util/graph.h
@@ -315,6 +315,9 @@ class grapht
   std::vector<node_indext> get_predecessors(const node_indext &n) const;
   std::vector<node_indext> get_successors(const node_indext &n) const;
   void output_dot(std::ostream &out) const;
+  void for_each_predecessor(
+    const node_indext &n,
+    std::function<void(const node_indext &)> f) const;
   void for_each_successor(
     const node_indext &n,
     std::function<void(const node_indext &)> f) const;
@@ -961,6 +964,17 @@ grapht<N>::get_successors(const node_indext &n) const
   return result;
 }
 
+template <class N>
+void grapht<N>::for_each_predecessor(
+  const node_indext &n,
+  std::function<void(const node_indext &)> f) const
+{
+  std::for_each(
+    nodes[n].in.begin(),
+    nodes[n].in.end(),
+    [&](const std::pair<node_indext, edget> &edge) { f(edge.first); });
+}
+
 template <class N>
 void grapht<N>::for_each_successor(
   const node_indext &n,

From 538070c24613de971e95ba15665c9451a59b1e58 Mon Sep 17 00:00:00 2001
From: johnfxgalea <jgoffice342@gmail.com>
Date: Sun, 30 May 2021 21:02:32 +0100
Subject: [PATCH 2/2] Add tests for for_each_predecessor() and
 for_each_successor()

---
 unit/util/graph.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/unit/util/graph.cpp b/unit/util/graph.cpp
index 40ff2a4fc59..30afb8f2441 100644
--- a/unit/util/graph.cpp
+++ b/unit/util/graph.cpp
@@ -329,6 +329,17 @@ SCENARIO("predecessors-successors-graph", "[core][util][graph]")
       REQUIRE(graph.get_successors(indices[0]).size() == 1);
       REQUIRE(graph.get_predecessors(indices[1]).size() == 1);
       REQUIRE(graph.get_successors(indices[1]).size() == 0);
+
+      int count = 0;
+      graph.for_each_predecessor(
+        indices[1], [&](const simple_grapht::node_indext &n) { count++; });
+      REQUIRE(count == 1);
+
+      // Refresh counter.
+      count = 0;
+      graph.for_each_successor(
+        indices[1], [&](const simple_grapht::node_indext &n) { count++; });
+      REQUIRE(count == 0);
     }
   }
 }