C#: Introduce caching or detecting the newest runtimes and fetching all file names in the source dir.

Author: michaelnebel

csharp/extractor/Semmle.Extraction.CSharp.Standalone/BuildAnalysis.cs

@@ -29,6 +29,7 @@ internal sealed partial class BuildAnalysis : IDisposable
         private readonly Options options;
         private readonly DirectoryInfo sourceDir;
         private readonly DotNet dotnet;
+        private readonly Lazy<IEnumerable<string>> allFiles;
 
         /// <summary>
         /// Performs a C# build analysis.
@@ -55,6 +56,7 @@ public BuildAnalysis(Options options, ProgressMonitor progressMonitor)
 
             this.progressMonitor.FindingFiles(options.SrcDir);
 
+            this.allFiles = new(() => GetFiles("*.*"));
             this.allSources = GetFiles("*.cs").ToArray();
             var allProjects = GetFiles("*.csproj");
             var solutions = options.SolutionFile is not null
@@ -227,6 +229,11 @@ private void UseReference(string reference) =>
         private void UseSource(FileInfo sourceFile) =>
             sources[sourceFile.FullName] = sourceFile.Exists;
 
+        /// <summary>
+        /// All files in the source directory.
+        /// </summary>
+        private IEnumerable<string> AllFiles => this.allFiles.Value;
+
         /// <summary>
         /// The list of resolved reference files.
         /// </summary>
@@ -369,8 +376,7 @@ private static bool IsGroupMatch(ReadOnlySpan<char> line, Regex regex, string gr
         /// </summary>
         private bool UseAspNetDlls()
         {
-            var allFiles = GetFiles("*.*");
-            foreach (var file in allFiles)
+            foreach (var file in AllFiles)
             {
                 try
                 {
@@ -414,8 +420,7 @@ private void DownloadMissingPackages(IEnumerable<string> restoreTargets)
                 nugetConfig = nugetConfigs.FirstOrDefault();
             }
 
-            var allFiles = GetFiles("*.*");
-            foreach (var file in allFiles)
+            foreach (var file in AllFiles)
             {
                 try
                 {

csharp/extractor/Semmle.Extraction.CSharp.Standalone/Runtime.cs

@@ -18,9 +18,15 @@ internal partial class Runtime
         private const string aspNetCoreApp = "Microsoft.AspNetCore.App";
 
         private readonly IDotNet dotNet;
+        private readonly Lazy<Dictionary<string, RuntimeVersion>> newestRuntimes;
+        private Dictionary<string, RuntimeVersion> NewestRuntimes => newestRuntimes.Value;
         private static string ExecutingRuntime => RuntimeEnvironment.GetRuntimeDirectory();
 
-        public Runtime(IDotNet dotNet) => this.dotNet = dotNet;
+        public Runtime(IDotNet dotNet)
+        {
+            this.dotNet = dotNet;
+            this.newestRuntimes = new(GetNewestRuntimes);
+        }
 
         internal record RuntimeVersion : IComparable<RuntimeVersion>
         {
@@ -150,11 +156,8 @@ public string GetRuntime(bool useSelfContained)
                 return ExecutingRuntime;
             }
 
-            // Gets the newest version of the installed runtimes.
-            var newestRuntimes = GetNewestRuntimes();
-
             // Location of the newest .NET Core Runtime.
-            if (newestRuntimes.TryGetValue(netCoreApp, out var netCoreVersion))
+            if (NewestRuntimes.TryGetValue(netCoreApp, out var netCoreVersion))
             {
                 return netCoreVersion.FullPath;
             }
@@ -168,16 +171,17 @@ public string GetRuntime(bool useSelfContained)
             return ExecutingRuntime;
         }
 
+        /// <summary>
+        /// Gets the ASP.NET runtime location to use for extraction, if one exists.
+        /// </summary>
         public string? GetAspRuntime()
         {
-            var newestRuntimes = GetNewestRuntimes();
-
             // Location of the newest ASP.NET Core Runtime.
-            if (newestRuntimes.TryGetValue(aspNetCoreApp, out var aspNetCoreVersion))
+            if (NewestRuntimes.TryGetValue(aspNetCoreApp, out var aspNetCoreVersion))
             {
                 return aspNetCoreVersion.FullPath;
             }
             return null;
         }
     }
-}
+}