Add wallclock timeout to PNS walkaround

WALKAROUND::singlestep is used by both shove and walkaround modes and
can bog down when applied to clusters with many objects.  In these
cases, we are unlikely to find a viable solution and it is beter to
allow the user to find a different ending position

(cherry picked from commit d9cfb94281)

common/advanced_config.cpp

@@ -128,6 +128,7 @@ static const wxChar ExcludeFromSimulationLineWidth[] = wxT( "ExcludeFromSimulati
 static const wxChar GitIconRefreshInterval[] = wxT( "GitIconRefreshInterval" );
 static const wxChar ConfigurableToolbars[] = wxT( "ConfigurableToolbars" );
 static const wxChar MaxPastedTextLength[] = wxT( "MaxPastedTextLength" );
+static const wxChar PNSProcessClusterTimeout[] = wxT( "PNSProcessClusterTimeout" );
 
 } // namespace KEYS
 
@@ -312,6 +313,8 @@ ADVANCED_CFG::ADVANCED_CFG()
 
     m_MaxPastedTextLength = 100;
 
+    m_PNSProcessClusterTimeout = 100; // Default: 100 ms
+
     loadFromConfigFile();
 }
 
@@ -602,6 +605,9 @@ void ADVANCED_CFG::loadSettings( wxConfigBase& aCfg )
                                                   &m_MaxPastedTextLength,
                                                   m_MaxPastedTextLength, 0, 100000 ) );
 
+    configParams.push_back( new PARAM_CFG_INT( true, AC_KEYS::PNSProcessClusterTimeout,
+                                               &m_PNSProcessClusterTimeout, 100, 10, 10000 ) );
+
     // Special case for trace mask setting...we just grab them and set them immediately
     // Because we even use wxLogTrace inside of advanced config
     wxString traceMasks;

include/advanced_config.h

@@ -757,6 +757,15 @@ public:
      */
     int m_MaxPastedTextLength;
 
+    /**
+     * Timeout for the PNS router's processCluster wallclock timeout, in milliseconds.
+     *
+     * Setting name: "PNSProcessClusterTimeoutMs"
+     * Valid values: 10 to 10000
+     * Default value: 100
+     */
+    int m_PNSProcessClusterTimeout;
+
     ///@}
 
 private:

pcbnew/router/pns_walkaround.cpp

@@ -19,6 +19,8 @@
  * with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <chrono>
+#include <advanced_config.h>
 #include <optional>
 
 #include <geometry/shape_line_chain.h>
@@ -138,10 +140,29 @@ bool WALKAROUND::singleStep()
 
     auto processCluster = [ & ] ( TOPOLOGY::CLUSTER& aCluster, LINE& aLine, bool aCw ) -> bool
     {
+        using namespace std::chrono;
+        auto start_time = steady_clock::now();
+
+        int timeout_ms = ADVANCED_CFG::GetCfg().m_PNSProcessClusterTimeout;
+
         PNS_DBG( Dbg(), BeginGroup, wxString::Format( "cluster-details [cw %d]", aCw?1:0 ), 1 );
 
         for( auto& clItem : aCluster.m_items )
         {
+            // Check for wallclock timeout
+            // Emprically, 100ms seems to be about where you're not going to find a valid path
+            // if you haven't found it by then.  This allows the user to adjust their mouse position
+            // to get a better path without waiting too long.
+            auto now = steady_clock::now();
+            auto elapsed = duration_cast<milliseconds>( now - start_time ).count();
+
+            if( elapsed > timeout_ms )
+            {
+                PNS_DBG( Dbg(), Message, wxString::Format( "processCluster timeout after %d ms", timeout_ms ) );
+                PNS_DBGN( Dbg(), EndGroup );
+                return false;
+            }
+
             int clearance = m_world->GetClearance( clItem, &aLine, false );
             SHAPE_LINE_CHAIN hull = clItem->Hull( clearance + 1000, aLine.Width(), aLine.Layer() );