Sorted modules by the dependencies of their libraries, if any, before parsing.

Signed-off-by: Dimitar Dobrev <dpldobrev@protonmail.com>

src/Generator/Driver.cs

@@ -14,6 +14,7 @@ using Microsoft.CSharp;
 using CppSharp.Parser;
 using System;
 using System.Reflection;
+using CppSharp.Utils;
 
 namespace CppSharp
 {
@@ -98,6 +99,23 @@ namespace CppSharp
                 Options.SetupMSVC();
         }
 
+        public void SortModulesByDependencies()
+        {
+            if (Options.Modules.All(m => m.Libraries.Any()))
+            {
+                var sortedModules = Options.Modules.TopologicalSort(m =>
+                {
+                    return from library in Symbols.Libraries
+                           where m.Libraries.Contains(library.FileName)
+                           from module in Options.Modules
+                           where library.Dependencies.Intersect(module.Libraries).Any()
+                           select module;
+                });
+                Options.Modules.Clear();
+                Options.Modules.AddRange(sortedModules);
+            }
+        }
+
         void OnSourceFileParsed(IList<SourceFile> files, ParserResult result)
         {
             OnFileParsed(files.Select(f => f.Path), result);
@@ -492,6 +510,7 @@ namespace CppSharp
             if (!options.Quiet)
                 Log.Message("Parsing code...");
 
+            driver.SortModulesByDependencies();
             driver.BuildParseOptions();
 
             if (!driver.ParseCode())

src/Generator/Utils/IEnumerableExtensions.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+
+namespace CppSharp.Utils
+{
+    public static class IEnumerableExtensions
+    {
+        public static IList<T> TopologicalSort<T>(this ICollection<T> source, Func<T, IEnumerable<T>> dependencies, bool throwOnCycle = false)
+        {
+            var sorted = new List<T>();
+            var visited = new HashSet<T>();
+
+            foreach (var item in source)
+                Visit(item, source, visited, sorted, dependencies, throwOnCycle);
+
+            return sorted;
+        }
+
+        private static void Visit<T>(T item, ICollection<T> source, ISet<T> visited, ICollection<T> sorted, Func<T, IEnumerable<T>> dependencies, bool throwOnCycle)
+        {
+            if (!visited.Contains(item))
+            {
+                visited.Add(item);
+
+                foreach (var dep in dependencies(item))
+                    Visit(dep, source, visited, sorted, dependencies, throwOnCycle);
+
+                if (source.Contains(item))
+                {
+                    sorted.Add(item);                    
+                }
+            }
+            else
+            {
+                if (throwOnCycle && !sorted.Contains(item))
+                    throw new Exception("Cyclic dependency found");
+            }
+        }
+    }
+}