C#: Move dependency related files into a new project.

csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/SolutionFile.cs

@@ -0,0 +1,75 @@
+using Microsoft.Build.Construction;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace Semmle.BuildAnalyser
+{
+    /// <summary>
+    /// Access data in a .sln file.
+    /// </summary>
+    internal class SolutionFile
+    {
+        private readonly Microsoft.Build.Construction.SolutionFile solutionFile;
+
+        private string FullPath { get; }
+
+        /// <summary>
+        /// Read the file.
+        /// </summary>
+        /// <param name="filename">The filename of the .sln.</param>
+        public SolutionFile(string filename)
+        {
+            // SolutionFile.Parse() expects a rooted path.
+            FullPath = Path.GetFullPath(filename);
+            solutionFile = Microsoft.Build.Construction.SolutionFile.Parse(FullPath);
+        }
+
+        /// <summary>
+        /// Projects directly included in the .sln file.
+        /// </summary>
+        public IEnumerable<string> MsBuildProjects
+        {
+            get
+            {
+                return solutionFile.ProjectsInOrder
+                    .Where(p => p.ProjectType == SolutionProjectType.KnownToBeMSBuildFormat)
+                    .Select(p => p.AbsolutePath)
+                    .Select(p => Path.DirectorySeparatorChar == '/' ? p.Replace("\\", "/") : p);
+            }
+        }
+
+        /// <summary>
+        /// Projects included transitively via a subdirectory.
+        /// </summary>
+        public IEnumerable<string> NestedProjects
+        {
+            get
+            {
+                return solutionFile.ProjectsInOrder
+                    .Where(p => p.ProjectType == SolutionProjectType.SolutionFolder)
+                    .Where(p => Directory.Exists(p.AbsolutePath))
+                    .SelectMany(p => new DirectoryInfo(p.AbsolutePath).EnumerateFiles("*.csproj", SearchOption.AllDirectories))
+                    .Select(f => f.FullName);
+            }
+        }
+
+        /// <summary>
+        /// List of projects which were mentioned but don't exist on disk.
+        /// </summary>
+        public IEnumerable<string> MissingProjects
+        {
+            get
+            {
+                // Only projects in the solution file can be missing.
+                // (NestedProjects are located on disk so always exist.)
+                return MsBuildProjects.Where(p => !File.Exists(p));
+            }
+        }
+
+        /// <summary>
+        /// The list of project files.
+        /// </summary>
+        public IEnumerable<string> Projects => MsBuildProjects.Concat(NestedProjects);
+    }
+}