Module loading support (#990)

Co-authored-by: lph <philipp.luethi@sva-ag.ch>
Co-authored-by: Marko Lahma <marko.lahma@gmail.com>
Co-authored-by: Sébastien Ros <sebastienros@gmail.com>

Jint.Tests.Test262/Language/ModuleTestHost.cs

@@ -0,0 +1,51 @@
+using System;
+using System.Collections.Generic;
+using System.Reflection;
+using System.IO;
+using Jint.Native;
+using Jint.Native.Object;
+using Jint.Runtime;
+using Jint.Runtime.Interop;
+
+namespace Jint.Tests.Test262.Language
+{
+    // Hacky way to get objects from assert.js and sta.js into the module context
+    internal sealed class ModuleTestHost : Host
+    {
+        private readonly static Dictionary<string, JsValue> _staticValues = new();
+
+        static ModuleTestHost()
+        {
+            var assemblyPath = new Uri(typeof(ModuleTestHost).GetTypeInfo().Assembly.Location).LocalPath;
+            var assemblyDirectory = new FileInfo(assemblyPath).Directory;
+
+            var basePath = assemblyDirectory.Parent.Parent.Parent.FullName;
+
+            var engine = new Engine();
+            var assertSource = File.ReadAllText(Path.Combine(basePath, "harness", "assert.js"));
+            var staSource = File.ReadAllText(Path.Combine(basePath, "harness", "sta.js"));
+
+            engine.Execute(assertSource);
+            engine.Execute(staSource);
+
+            _staticValues["assert"] = engine.GetValue("assert");
+            _staticValues["Test262Error"] = engine.GetValue("Test262Error");
+            _staticValues["$ERROR"] = engine.GetValue("$ERROR");
+            _staticValues["$DONOTEVALUATE"] = engine.GetValue("$DONOTEVALUATE");
+
+            _staticValues["print"] = new ClrFunctionInstance(engine, "print", (thisObj, args) => TypeConverter.ToString(args.At(0)));
+        }
+
+        protected override ObjectInstance CreateGlobalObject(Realm realm)
+        {
+            var globalObj = base.CreateGlobalObject(realm);
+
+            foreach (var key in _staticValues.Keys)
+            {
+                globalObj.FastAddProperty(key, _staticValues[key], true, true, true);
+            }
+
+            return globalObj;
+        }
+    }
+}

Jint.Tests.Test262/Language/ModuleTests.cs

@@ -1,31 +1,72 @@
+using Jint.Runtime;
+using Jint.Runtime.Modules;
+using System;
 using Xunit;
+using Xunit.Sdk;
 
-namespace Jint.Tests.Test262.Language
+namespace Jint.Tests.Test262.Language;
+
+public class ModuleTests : Test262Test
 {
-    public class ModuleTests : Test262Test
+    [Theory(DisplayName = "language\\module-code")]
+    [MemberData(nameof(SourceFiles), "language\\module-code", false)]
+    [MemberData(nameof(SourceFiles), "language\\module-code", true, Skip = "Skipped")]
+    protected void ModuleCode(SourceFile sourceFile)
+    {
+        RunModuleTest(sourceFile);
+    }
+
+    [Theory(DisplayName = "language\\export")]
+    [MemberData(nameof(SourceFiles), "language\\export", false)]
+    [MemberData(nameof(SourceFiles), "language\\export", true, Skip = "Skipped")]
+    protected void Export(SourceFile sourceFile)
+    {
+        RunModuleTest(sourceFile);
+    }
+
+    [Theory(DisplayName = "language\\import")]
+    [MemberData(nameof(SourceFiles), "language\\import", false)]
+    [MemberData(nameof(SourceFiles), "language\\import", true, Skip = "Skipped")]
+    protected void Import(SourceFile sourceFile)
+    {
+        RunModuleTest(sourceFile);
+    }
+
+    private static void RunModuleTest(SourceFile sourceFile)
     {
-        [Theory(DisplayName = "language\\module-code", Skip = "TODO")]
-        [MemberData(nameof(SourceFiles), "language\\module-code", false)]
-        [MemberData(nameof(SourceFiles), "language\\module-code", true, Skip = "Skipped")]
-        protected void ModuleCode(SourceFile sourceFile)
+        if (sourceFile.Skip)
         {
-            RunTestInternal(sourceFile);
+            return;
         }
 
-        [Theory(DisplayName = "language\\export")]
-        [MemberData(nameof(SourceFiles), "language\\export", false)]
-        [MemberData(nameof(SourceFiles), "language\\export", true, Skip = "Skipped")]
-        protected void Export(SourceFile sourceFile)
+        var code = sourceFile.Code;
+
+        var options = new Options();
+        options.Host.Factory = _ => new ModuleTestHost();
+        options.Modules.Enabled = true;
+        options.WithModuleLoader(new DefaultModuleLoader(null));
+
+        var engine = new Engine(options);
+
+        var negative = code.IndexOf("negative:", StringComparison.OrdinalIgnoreCase) != -1;
+        string lastError = null;
+
+        try
+        {
+            engine.LoadModule(sourceFile.FullPath);
+        }
+        catch (JavaScriptException ex)
+        {
+            lastError = ex.ToString();
+        }
+        catch (Exception ex)
         {
-            RunTestInternal(sourceFile);
+            lastError = ex.ToString();
         }
 
-        [Theory(DisplayName = "language\\import", Skip = "TODO")]
-        [MemberData(nameof(SourceFiles), "language\\import", false)]
-        [MemberData(nameof(SourceFiles), "language\\import", true, Skip = "Skipped")]
-        protected void Import(SourceFile sourceFile)
+        if (!negative && !string.IsNullOrWhiteSpace(lastError))
         {
-            RunTestInternal(sourceFile);
+            throw new XunitException(lastError);
         }
     }
 }

Jint.Tests.Test262/Test262Test.cs

@@ -208,6 +208,13 @@ public static IEnumerable<object[]> SourceFiles(string pathPrefix, bool skipped)
 
             foreach (var file in files)
             {
+                if (file.IndexOf("_FIXTURE", StringComparison.OrdinalIgnoreCase) != -1)
+                {
+                    // Files bearing a name which includes the sequence _FIXTURE MUST NOT be interpreted
+                    // as standalone tests; they are intended to be referenced by test files.
+                    continue;
+                }
+
                 var name = file.Substring(fixturesPath.Length + 1).Replace("\\", "/");
                 bool skip = _skipReasons.TryGetValue(name, out var reason);
 
@@ -288,6 +295,18 @@ public static IEnumerable<object[]> SourceFiles(string pathPrefix, bool skipped)
                                 skip = true;
                                 reason = "resizable-arraybuffer not implemented";
                                 break;
+                            case "json-modules":
+                                skip = true;
+                                reason = "json-modules not implemented";
+                                break;
+                            case "top-level-await":
+                                skip = true;
+                                reason = "top-level-await not implemented";
+                                break;
+                            case "import-assertions":
+                                skip = true;
+                                reason = "import-assertions not implemented";
+                                break;
                         }
                     }
                 }

Jint/Engine.Modules.cs

@@ -0,0 +1,33 @@
+using System.Collections.Generic;
+using Jint.Runtime.Modules;
+
+namespace Jint
+{
+    public partial class Engine
+    {
+        internal IModuleLoader ModuleLoader { get; set; }
+
+        private readonly Dictionary<ModuleCacheKey, JsModule> _modules = new();
+
+        public JsModule LoadModule(string specifier) => LoadModule(null, specifier);
+
+        internal JsModule LoadModule(string referencingModuleLocation, string specifier)
+        {
+            var key = new ModuleCacheKey(referencingModuleLocation ?? string.Empty, specifier);
+
+            if (_modules.TryGetValue(key, out var module))
+            {
+                return module;
+            }
+
+            var (loadedModule, location) = ModuleLoader.LoadModule(this, specifier, referencingModuleLocation);
+            module = new JsModule(this, _host.CreateRealm(), loadedModule, location.AbsoluteUri, false);
+
+            _modules[key] = module;
+
+            return module;
+        }
+
+        internal readonly record struct ModuleCacheKey(string ReferencingModuleLocation, string Specifier);
+    }
+}

Jint/EsprimaExtensions.cs

@@ -11,6 +11,7 @@
 using Jint.Runtime.Environments;
 using Jint.Runtime.Interpreter;
 using Jint.Runtime.Interpreter.Expressions;
+using Jint.Runtime.Modules;
 
 namespace Jint
 {
@@ -128,6 +129,7 @@ internal static string LiteralKeyToString(Literal literal)
             {
                 return TypeConverter.ToString(d);
             }
+
             return literal.Value as string ?? Convert.ToString(literal.Value, provider: null);
         }
 
@@ -204,6 +206,7 @@ internal static void GetBoundNames(this Node? parameter, List<string> target)
                     parameter = assignmentPattern.Left;
                     continue;
                 }
+
                 break;
             }
         }
@@ -256,6 +259,130 @@ internal static Record DefineMethod(this ClassProperty m, ObjectInstance obj, Ob
             return new Record(property, closure);
         }
 
+        internal static void GetImportEntries(this ImportDeclaration import, List<ImportEntry> importEntries, HashSet<string> requestedModules)
+        {
+            var source = import.Source.StringValue!;
+            var specifiers = import.Specifiers;
+            requestedModules.Add(source!);
+
+            foreach (var specifier in specifiers)
+            {
+                switch (specifier)
+                {
+                    case ImportNamespaceSpecifier namespaceSpecifier:
+                        importEntries.Add(new ImportEntry(source, "*", namespaceSpecifier.Local.GetModuleKey()));
+                        break;
+                    case ImportSpecifier importSpecifier:
+                        importEntries.Add(new ImportEntry(source, importSpecifier.Imported.GetModuleKey(), importSpecifier.Local.GetModuleKey()));
+                        break;
+                    case ImportDefaultSpecifier defaultSpecifier:
+                        importEntries.Add(new ImportEntry(source, "default", defaultSpecifier.Local.GetModuleKey()));
+                        break;
+                }
+            }
+        }
+
+        internal static void GetExportEntries(this ExportDeclaration export, List<ExportEntry> exportEntries, HashSet<string> requestedModules)
+        {
+            switch (export)
+            {
+                case ExportDefaultDeclaration defaultDeclaration:
+                    GetExportEntries(true, defaultDeclaration.Declaration, exportEntries);
+                    break;
+                case ExportAllDeclaration allDeclaration:
+                    //Note: there is a pending PR for Esprima to support exporting an imported modules content as a namespace i.e. 'export * as ns from "mod"'
+                    requestedModules.Add(allDeclaration.Source.StringValue!);
+                    exportEntries.Add(new(null, allDeclaration.Source.StringValue, "*", null));
+                    break;
+                case ExportNamedDeclaration namedDeclaration:
+                    var specifiers = namedDeclaration.Specifiers;
+                    if (specifiers.Count == 0)
+                    {
+                        GetExportEntries(false, namedDeclaration.Declaration!, exportEntries, namedDeclaration.Source?.StringValue);
+
+                        if (namedDeclaration.Source is not null)
+                        {
+                            requestedModules.Add(namedDeclaration.Source.StringValue!);
+                        }
+                    }
+                    else
+                    {
+                        foreach (var specifier in specifiers)
+                        {
+                            exportEntries.Add(new(specifier.Local.GetModuleKey(), namedDeclaration.Source?.StringValue, specifier.Exported.GetModuleKey(), null));
+                        }
+                    }
+
+                    break;
+            }
+        }
+
+        private static void GetExportEntries(bool defaultExport, StatementListItem declaration, List<ExportEntry> exportEntries, string? moduleRequest = null)
+        {
+            var names = GetExportNames(declaration);
+
+            if (names.Count == 0)
+            {
+                if (defaultExport)
+                {
+                    exportEntries.Add(new("default", null, null, "*default*"));
+                }
+            }
+            else
+            {
+                for (var i = 0; i < names.Count; i++)
+                {
+                    var name = names[i];
+                    var exportName = defaultExport ? "default" : name;
+                    exportEntries.Add(new(exportName, moduleRequest, null, name));
+                }
+            }
+        }
+
+        private static List<string> GetExportNames(StatementListItem declaration)
+        {
+            var result = new List<string>();
+
+            switch (declaration)
+            {
+                case FunctionDeclaration functionDeclaration:
+                    var funcName = functionDeclaration.Id?.Name;
+                    if (funcName is not null)
+                    {
+                        result.Add(funcName);
+                    }
+
+                    break;
+                case ClassDeclaration classDeclaration:
+                    var className = classDeclaration.Id?.Name;
+                    if (className is not null)
+                    {
+                        result.Add(className);
+                    }
+
+                    break;
+                case VariableDeclaration variableDeclaration:
+                    var declarators = variableDeclaration.Declarations;
+                    foreach (var declarator in declarators)
+                    {
+                        var varName = declarator.Id.As<Identifier>()?.Name;
+                        if (varName is not null)
+                        {
+                            result.Add(varName);
+                        }
+                    }
+
+                    break;
+            }
+
+            return result;
+        }
+
+        private static string? GetModuleKey(this Expression expression)
+        {
+            return (expression as Identifier)?.Name ?? (expression as Literal)?.StringValue;
+        }
+
         internal readonly record struct Record(JsValue Key, ScriptFunctionInstance Closure);
     }
 }