Refactor process starting and stdout and stderr reading

Author: tamasvajk

csharp/autobuilder/Semmle.Autobuild.Shared/BuildActions.cs

@@ -187,12 +187,12 @@ public class SystemBuildActions : IBuildActions
 
         bool IBuildActions.FileExists(string file) => File.Exists(file);
 
-        private static ProcessStartInfo GetProcessStartInfo(string exe, string arguments, string? workingDirectory, IDictionary<string, string>? environment, bool redirectStandardOutput)
+        private static ProcessStartInfo GetProcessStartInfo(string exe, string arguments, string? workingDirectory, IDictionary<string, string>? environment)
         {
             var pi = new ProcessStartInfo(exe, arguments)
             {
                 UseShellExecute = false,
-                RedirectStandardOutput = redirectStandardOutput
+                RedirectStandardOutput = true
             };
             if (workingDirectory is not null)
                 pi.WorkingDirectory = workingDirectory;
@@ -204,40 +204,22 @@ private static ProcessStartInfo GetProcessStartInfo(string exe, string arguments
 
         int IBuildActions.RunProcess(string exe, string args, string? workingDirectory, System.Collections.Generic.IDictionary<string, string>? env, BuildOutputHandler onOutput, BuildOutputHandler onError)
         {
-            var pi = GetProcessStartInfo(exe, args, workingDirectory, env, true);
-            using var p = new Process
-            {
-                StartInfo = pi
-            };
-            p.StartInfo.RedirectStandardError = true;
-            p.OutputDataReceived += new DataReceivedEventHandler((sender, e) => onOutput(e.Data));
-            p.ErrorDataReceived += new DataReceivedEventHandler((sender, e) => onError(e.Data));
-
-            p.Start();
+            var pi = GetProcessStartInfo(exe, args, workingDirectory, env);
+            pi.RedirectStandardError = true;
 
-            p.BeginErrorReadLine();
-            p.BeginOutputReadLine();
-
-            p.WaitForExit();
-            return p.ExitCode;
+            return pi.ReadOutput(out _, onOut: s => onOutput(s), onError: s => onError(s));
         }
 
         int IBuildActions.RunProcess(string cmd, string args, string? workingDirectory, IDictionary<string, string>? environment)
         {
-            var pi = GetProcessStartInfo(cmd, args, workingDirectory, environment, false);
-            using var p = Process.Start(pi);
-            if (p is null)
-            {
-                return -1;
-            }
-            p.WaitForExit();
-            return p.ExitCode;
+            var pi = GetProcessStartInfo(cmd, args, workingDirectory, environment);
+            return pi.ReadOutput(out _, onOut: Console.WriteLine, onError: null);
         }
 
         int IBuildActions.RunProcess(string cmd, string args, string? workingDirectory, IDictionary<string, string>? environment, out IList<string> stdOut)
         {
-            var pi = GetProcessStartInfo(cmd, args, workingDirectory, environment, true);
-            return pi.ReadOutput(out stdOut, printToConsole: false);
+            var pi = GetProcessStartInfo(cmd, args, workingDirectory, environment);
+            return pi.ReadOutput(out stdOut, onOut: null, onError: null);
         }
 
         void IBuildActions.DirectoryDelete(string dir, bool recursive) => Directory.Delete(dir, recursive);

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

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using Semmle.Util;
@@ -24,7 +25,8 @@ private ProcessStartInfo MakeDotnetStartInfo(string args)
             var startInfo = new ProcessStartInfo(Exec, args)
             {
                 UseShellExecute = false,
-                RedirectStandardOutput = true
+                RedirectStandardOutput = true,
+                RedirectStandardError = true
             };
             // Set the .NET CLI language to English to avoid localized output.
             startInfo.EnvironmentVariables["DOTNET_CLI_UI_LANGUAGE"] = "en";
@@ -35,7 +37,16 @@ private bool RunCommandAux(string args, out IList<string> output)
         {
             progressMonitor.RunningProcess($"{Exec} {args}");
             var pi = MakeDotnetStartInfo(args);
-            var exitCode = pi.ReadOutput(out output, true);
+            var threadId = $"[{Environment.CurrentManagedThreadId:D3}]";
+            void onOut(string s)
+            {
+                Console.Out.WriteLine($"{threadId} {s}");
+            }
+            void onError(string s)
+            {
+                Console.Error.WriteLine($"{threadId} {s}");
+            }
+            var exitCode = pi.ReadOutput(out output, onOut, onError);
             if (exitCode != 0)
             {
                 progressMonitor.CommandFailed(Exec, args, exitCode);

csharp/extractor/Semmle.Util/ProcessStartInfoExtensions.cs

@@ -8,38 +8,56 @@ public static class ProcessStartInfoExtensions
     {
         /// <summary>
         /// Runs this process, and returns the exit code, as well as the contents
-        /// of stdout in <paramref name="stdout"/>. If <paramref name="printToConsole"/>
-        /// is true, then stdout is printed to the console and each line is prefixed
-        /// with the thread id.
+        /// of stdout in <paramref name="stdout"/>.
         /// </summary>
-        public static int ReadOutput(this ProcessStartInfo pi, out IList<string> stdout, bool printToConsole)
+        public static int ReadOutput(this ProcessStartInfo pi, out IList<string> stdout, Action<string>? onOut, Action<string>? onError)
         {
-            stdout = new List<string>();
-            using var process = Process.Start(pi);
+            var @out = new List<string>();
+            using var process = new Process
+            {
+                StartInfo = pi
+            };
 
-            if (process is null)
+            if (process.StartInfo.RedirectStandardOutput && !pi.UseShellExecute)
             {
-                return -1;
-            }
+                process.OutputDataReceived += new DataReceivedEventHandler((sender, e) =>
+                {
+                    if (e.Data == null)
+                    {
+                        return;
+                    }
 
-            if (pi.RedirectStandardOutput && !pi.UseShellExecute)
+                    onOut?.Invoke(e.Data);
+                    @out.Add(e.Data);
+                });
+            }
+            if (process.StartInfo.RedirectStandardError && !pi.UseShellExecute)
             {
-                string? s;
-                do
+                process.ErrorDataReceived += new DataReceivedEventHandler((sender, e) =>
                 {
-                    s = process.StandardOutput.ReadLine();
-                    if (s is not null)
+                    if (e.Data == null)
                     {
-                        if (printToConsole)
-                        {
-                            Console.WriteLine($"[{Environment.CurrentManagedThreadId:D3}] {s}");
-                        }
-                        stdout.Add(s);
+                        return;
                     }
-                }
-                while (s is not null);
+
+                    onError?.Invoke(e.Data);
+                });
             }
+
+            process.Start();
+
+            if (process.StartInfo.RedirectStandardError)
+            {
+                process.BeginErrorReadLine();
+            }
+
+            if (process.StartInfo.RedirectStandardOutput)
+            {
+                process.BeginOutputReadLine();
+            }
+
             process.WaitForExit();
+            stdout = @out;
             return process.ExitCode;
         }
     }