ConfigMerger.cs

//
// Copyright (c) 2011 Francois Valdy
//
//   Licensed under the Apache License, Version 2.0 (the "License");
//   you may not use this file except in compliance with the License.
//   You may obtain a copy of the License at
//
//       http://www.apache.org/licenses/LICENSE-2.0
//
//   Unless required by applicable law or agreed to in writing, software
//   distributed under the License is distributed on an "AS IS" BASIS,
//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//   See the License for the specific language governing permissions and
//   limitations under the License.
//
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Xml.Linq;

namespace ILRepacking
{
    internal static class ConfigMerger
    {
        internal static void Process(ILRepack repack)
        {
            try
            {
                var validConfigFiles = new List<XDocument>();
                foreach (string assembly in repack.MergedAssemblyFiles)
                {
                    string assemblyConfig = assembly + ".config";
                    if (!File.Exists(assemblyConfig))
                        continue;
                    var doc = XDocument.Load(assemblyConfig);
                    validConfigFiles.Add(doc);
                }

                if (validConfigFiles.Count == 0)
                    return;

                repack.Logger.Verbose($"Merging config files: {string.Join(",", validConfigFiles)}...");

                var firstFile = validConfigFiles[0];
                validConfigFiles.RemoveAt(0);
                foreach (var configFile in validConfigFiles)
                {
                    MergeElements(firstFile.Root, configFile.Root);
                }
                firstFile.Save(repack.Options.OutputFile + ".config");
            }
            catch (Exception e)
            {
                repack.Logger.Error("Failed to merge configuration files: " + e);
            }
        }

        // determine which elements we consider the same
        private static bool AreEquivalent(XElement a, XElement b)
        {
            if (a.Name != b.Name) return false;
            if (!a.HasAttributes && !b.HasAttributes) return true;
            if (!a.HasAttributes || !b.HasAttributes) return false;
            if (a.Attributes().Count() != b.Attributes().Count()) return false;

            return a.Attributes().All(attA => b.Attributes(attA.Name)
                .Count(attB => attB.Value == attA.Value) != 0);
        }

        // Merge "merged" document B into "source" A
        private static void MergeElements(XElement parentA, XElement parentB)
        {
            // merge per-element content from parentB into parentA
            //
            foreach (XNode childB in parentB.DescendantNodes())
            {
                if (childB is XText) continue;

                // merge childB with first equivalent childA
                // equivalent childB1, childB2,.. will be combined
                //
                bool isMatchFound = false;
                foreach (XElement childA in parentA.Descendants())
                {
                    if (AreEquivalent(childA, (XElement)childB))
                    {
                        MergeElements(childA, (XElement)childB);
                        isMatchFound = true;
                        break;
                    }
                }

                // if there is no equivalent childA, add childB into parentA
                //
                if (!isMatchFound) parentA.Add(childB);
            }
        }
    }
}