Exit with error code on errors

When run by a script, the script needs to know if the requested operation was
succesful.

This patch makes sure error codes are returned for a number of unhandled error
conditions.

DepotDownloader/ContentDownloader.cs

@@ -11,6 +11,11 @@ using System.Threading.Tasks;
 
 namespace DepotDownloader
 {
+    public class ContentDownloaderException : System.Exception
+    {
+        public ContentDownloaderException( String value ) : base( value ) {}
+    }
+
     static class ContentDownloader
     {
         public const uint INVALID_APP_ID = uint.MaxValue;
@@ -402,8 +407,7 @@ namespace DepotDownloader
                 else
                 {
                     string contentName = GetAppOrDepotName( INVALID_DEPOT_ID, appId );
-                    Console.WriteLine( "App {0} ({1}) is not available from this account.", appId, contentName );
-                    return;
+                    throw new ContentDownloaderException( String.Format( "App {0} ({1}) is not available from this account.", appId, contentName ) );
                 }
             }
 
@@ -452,14 +456,11 @@ namespace DepotDownloader
                 }
                 if ( depotIDs == null || ( depotIDs.Count == 0 && depotId == INVALID_DEPOT_ID ) )
                 {
-                    Console.WriteLine( "Couldn't find any depots to download for app {0}", appId );
-                    return;
+                    throw new ContentDownloaderException( String.Format( "Couldn't find any depots to download for app {0}", appId ) );
                 }
                 else if ( depotIDs.Count == 0 )
                 {
-                    Console.Write( "Depot {0} not listed for app {1}", depotId, appId );
-                    Console.WriteLine();
-                    return;
+                    throw new ContentDownloaderException( String.Format( "Depot {0} not listed for app {1}", depotId, appId ) );
                 }
             }
 
@@ -481,6 +482,7 @@ namespace DepotDownloader
             catch ( OperationCanceledException )
             {
                 Console.WriteLine( "App {0} was not completely downloaded.", appId );
+                throw;
             }
         }
 

DepotDownloader/Program.cs

@@ -10,15 +10,15 @@ namespace DepotDownloader
 {
     class Program
     {
-        static void Main( string[] args )
+        static int Main( string[] args )
             => MainAsync( args ).GetAwaiter().GetResult();
 
-        static async Task MainAsync( string[] args )
+        static async Task<int> MainAsync( string[] args )
         {
             if ( args.Length == 0 )
             {
                 PrintUsage();
-                return;
+                return 1;
             }
 
             DebugLog.Enabled = false;
@@ -92,10 +92,28 @@ namespace DepotDownloader
                 #region Pubfile Downloading
 
                 if ( InitializeSteam( username, password ) )
+                {
+                    try
                     {
                         await ContentDownloader.DownloadPubfileAsync( pubFile ).ConfigureAwait( false );
+                    }
+                    catch ( Exception ex ) when (
+                        ex is ContentDownloaderException
+                        || ex is OperationCanceledException )
+                    {
+                        Console.WriteLine( ex.Message );
+                        return 1;
+                    }
+                    finally
+                    {
                         ContentDownloader.ShutdownSteam3();
                     }
+                }
+                else
+                {
+                    Console.WriteLine( "Error: InitializeSteam failed" );
+                    return 1;
+                }
 
                 #endregion
             }
@@ -112,14 +130,14 @@ namespace DepotDownloader
                 if ( ContentDownloader.Config.DownloadAllPlatforms && !String.IsNullOrEmpty( os ) )
                 {
                     Console.WriteLine("Error: Cannot specify -os when -all-platforms is specified.");
-                    return;
+                    return 1;
                 }
 
                 uint appId = GetParameter<uint>( args, "-app", ContentDownloader.INVALID_APP_ID );
                 if ( appId == ContentDownloader.INVALID_APP_ID )
                 {
                     Console.WriteLine( "Error: -app not specified!" );
-                    return;
+                    return 1;
                 }
 
                 uint depotId;
@@ -138,18 +156,37 @@ namespace DepotDownloader
                     if ( depotId == ContentDownloader.INVALID_DEPOT_ID && manifestId != ContentDownloader.INVALID_MANIFEST_ID )
                     {
                         Console.WriteLine( "Error: -manifest requires -depot to be specified" );
-                        return;
+                        return 1;
                     }
                 }
 
                 if ( InitializeSteam( username, password ) )
+                {
+                    try
                     {
                         await ContentDownloader.DownloadAppAsync( appId, depotId, manifestId, branch, os, isUGC ).ConfigureAwait( false );
+                    }
+                    catch ( Exception ex ) when (
+                        ex is ContentDownloaderException
+                        || ex is OperationCanceledException )
+                    {
+                        Console.WriteLine( ex.Message );
+                        return 1;
+                    }
+                    finally
+                    {
                         ContentDownloader.ShutdownSteam3();
                     }
+                }
+                else
+                {
+                    Console.WriteLine( "Error: InitializeSteam failed" );
+                    return 1;
+                }
 
                 #endregion
             }
+        return 0;
         }
 
         static bool InitializeSteam( string username, string password )