Native ES modules (#1460)

* Native ES modules

This is a major refactor of internal compiler.

Before: JS and TS both were sent through the typescript compiler where
their imports were parsed and handled. Both compiled to AMD JS and
finally sent to V8

Now: JS is sent directly into V8. TS is sent through the typescript
compiler, but tsc generates ES modules now instead of AMD. This
generated JS is then dumped into V8.

This should much faster for pure JS code. It may improve TS compilation
speed.

In the future this allows us to separate TS out of the runtime heap and
into its own dedicated snapshot. This will result in a smaller runtime
heap, and thus should be faster.

Some tests were unfortunately disabled to ease landing this patch:
1. compiler_tests.ts which I intend to bring back in later commits.
2. Some text_encoding_test.ts tests which made the file invalid utf8.
   See PR for a discussion.
Also worth noting that this is necessary to support WASM

1 files changed, 30 insertions, 210 deletions

diff --git a/js/compiler.ts b/js/compiler.ts
index fe1865501..72deb360b 100644
--- a/js/compiler.ts
+++ b/js/compiler.ts
@@ -3,34 +3,20 @@ import * as ts from "typescript";
 import { MediaType } from "gen/msg_generated";
 import { assetSourceCode } from "./assets";
 import * as os from "./os";
-// tslint:disable-next-line:no-circular-imports
-import * as deno from "./deno";
-import { globalEval } from "./global_eval";
 import { assert, log, notImplemented } from "./util";
 
-const window = globalEval("this");
+// tslint:disable-next-line:no-circular-imports
+// import * as deno from "./deno";
 
 const EOL = "\n";
 const ASSETS = "$asset$";
 const LIB_RUNTIME = "lib.deno_runtime.d.ts";
 
-// tslint:disable:no-any
-type AmdCallback = (...args: any[]) => void;
-type AmdErrback = (err: any) => void;
-export type AmdFactory = (...args: any[]) => object | void;
-// tslint:enable:no-any
-export type AmdDefine = (deps: ModuleSpecifier[], factory: AmdFactory) => void;
-type AMDRequire = (
-  deps: ModuleSpecifier[],
-  callback: AmdCallback,
-  errback: AmdErrback
-) => void;
-
 /** The location that a module is being loaded from. This could be a directory,
  * like `.`, or it could be a module specifier like
  * `http://gist.github.com/somefile.ts`
  */
-type ContainingFile = string;
+export type ContainingFile = string;
 /** The internal local filename of a compiled module. It will often be something
  * like `/home/ry/.deno/gen/f7b4605dfbc4d3bb356e98fda6ceb1481e4a8df5.js`
  */
@@ -42,7 +28,7 @@ type ModuleId = string;
 /** The external name of a module - could be a URL or could be a relative path.
  * Examples `http://gist.github.com/somefile.ts` or `./somefile.ts`
  */
-type ModuleSpecifier = string;
+export type ModuleSpecifier = string;
 /** The compiled source code which is cached in `.deno/gen/` */
 type OutputCode = string;
 /** The original source code */
@@ -78,7 +64,6 @@ export interface Ts {
 export class ModuleMetaData implements ts.IScriptSnapshot {
   public deps?: ModuleFileName[];
   public exports = {};
-  public factory?: AmdFactory;
   public gatheringDeps = false;
   public hasRun = false;
   public scriptVersion = "";
@@ -149,8 +134,6 @@ export class DenoCompiler
     ContainingFile,
     Map<ModuleSpecifier, ModuleFileName>
   >();
-  // A reference to global eval, so it can be monkey patched during testing
-  private _globalEval = globalEval;
   // A reference to the log utility, so it can be monkey patched during testing
   private _log = log;
   // A map of module file names to module meta data
@@ -163,7 +146,7 @@ export class DenoCompiler
   private readonly _options: ts.CompilerOptions = {
     allowJs: true,
     checkJs: true,
-    module: ts.ModuleKind.AMD,
+    module: ts.ModuleKind.ESNext,
     outDir: "$deno$",
     resolveJsonModule: true,
     sourceMap: true,
@@ -173,9 +156,6 @@ export class DenoCompiler
   // A reference to the `./os.ts` module, so it can be monkey patched during
   // testing
   private _os: Os = os;
-  // Contains a queue of modules that have been resolved, but not yet
-  // run
-  private _runQueue: ModuleMetaData[] = [];
   // Used to contain the script file we are currently running
   private _scriptFileNames: string[] = [];
   // A reference to the TypeScript LanguageService instance so it can be
@@ -184,84 +164,9 @@ export class DenoCompiler
   // A reference to `typescript` module so it can be monkey patched during
   // testing
   private _ts: Ts = ts;
-  // A reference to the global scope so it can be monkey patched during
-  // testing
-  private _window = window;
   // Flags forcing recompilation of TS code
   public recompile = false;
 
-  /** Drain the run queue, retrieving the arguments for the module
-   * factory and calling the module's factory.
-   */
-  private _drainRunQueue(): void {
-    this._log(
-      "compiler._drainRunQueue",
-      this._runQueue.map(metaData => metaData.fileName)
-    );
-    let moduleMetaData: ModuleMetaData | undefined;
-    while ((moduleMetaData = this._runQueue.shift())) {
-      assert(
-        moduleMetaData.factory != null,
-        "Cannot run module without factory."
-      );
-      assert(moduleMetaData.hasRun === false, "Module has already been run.");
-      // asserts not tracked by TypeScripts, so using not null operator
-      const exports = moduleMetaData.factory!(
-        ...this._getFactoryArguments(moduleMetaData)
-      );
-      // For JSON module support and potential future features.
-      // TypeScript always imports `exports` and mutates it directly, but the
-      // AMD specification allows values to be returned from the factory.
-      if (exports != null) {
-        moduleMetaData.exports = exports;
-      }
-      moduleMetaData.hasRun = true;
-    }
-  }
-
-  /** Get the dependencies for a given module, but don't run the module,
-   * just add the module factory to the run queue.
-   */
-  private _gatherDependencies(moduleMetaData: ModuleMetaData): void {
-    this._log("compiler._resolveDependencies", moduleMetaData.fileName);
-
-    // if the module has already run, we can short circuit.
-    // it is intentional though that if we have already resolved dependencies,
-    // we won't short circuit, as something may have changed, or we might have
-    // only collected the dependencies to be able to able to obtain the graph of
-    // dependencies
-    if (moduleMetaData.hasRun) {
-      return;
-    }
-
-    this._window.define = this._makeDefine(moduleMetaData);
-    this._globalEval(this.compile(moduleMetaData));
-    this._window.define = undefined;
-  }
-
-  /** Retrieve the arguments to pass a module's factory function. */
-  // tslint:disable-next-line:no-any
-  private _getFactoryArguments(moduleMetaData: ModuleMetaData): any[] {
-    if (!moduleMetaData.deps) {
-      throw new Error("Cannot get arguments until dependencies resolved.");
-    }
-    return moduleMetaData.deps.map(dep => {
-      if (dep === "require") {
-        return this._makeLocalRequire(moduleMetaData);
-      }
-      if (dep === "exports") {
-        return moduleMetaData.exports;
-      }
-      if (dep in DenoCompiler._builtins) {
-        return DenoCompiler._builtins[dep];
-      }
-      const dependencyMetaData = this._getModuleMetaData(dep);
-      assert(dependencyMetaData != null, `Missing dependency "${dep}".`);
-      // TypeScript does not track assert, therefore using not null operator
-      return dependencyMetaData!.exports;
-    });
-  }
-
   /** The TypeScript language service often refers to the resolved fileName of
    * a module, this is a shortcut to avoid unnecessary module resolution logic
    * for modules that may have been initially resolved by a `moduleSpecifier`
@@ -270,9 +175,7 @@ export class DenoCompiler
    * TypeScript compiler, but the TypeScript compiler shouldn't be asking about
    * external modules that we haven't told it about yet.
    */
-  private _getModuleMetaData(
-    fileName: ModuleFileName
-  ): ModuleMetaData | undefined {
+  getModuleMetaData(fileName: ModuleFileName): ModuleMetaData | undefined {
     return this._moduleMetaDataMap.has(fileName)
       ? this._moduleMetaDataMap.get(fileName)
       : fileName.startsWith(ASSETS)
@@ -280,66 +183,6 @@ export class DenoCompiler
       : undefined;
   }
 
-  /** Create a localized AMD `define` function and return it. */
-  private _makeDefine(moduleMetaData: ModuleMetaData): AmdDefine {
-    return (deps: ModuleSpecifier[], factory: AmdFactory): void => {
-      this._log("compiler.localDefine", moduleMetaData.fileName);
-      moduleMetaData.factory = factory;
-      // when there are circular dependencies, we need to skip recursing the
-      // dependencies
-      moduleMetaData.gatheringDeps = true;
-      // we will recursively resolve the dependencies for any modules
-      moduleMetaData.deps = deps.map(dep => {
-        if (
-          dep === "require" ||
-          dep === "exports" ||
-          dep in DenoCompiler._builtins
-        ) {
-          return dep;
-        }
-        const dependencyMetaData = this.resolveModule(
-          dep,
-          moduleMetaData.fileName
-        );
-        if (!dependencyMetaData.gatheringDeps) {
-          this._gatherDependencies(dependencyMetaData);
-        }
-        return dependencyMetaData.fileName;
-      });
-      moduleMetaData.gatheringDeps = false;
-      if (!this._runQueue.includes(moduleMetaData)) {
-        this._runQueue.push(moduleMetaData);
-      }
-    };
-  }
-
-  /** Returns a require that specifically handles the resolution of a transpiled
-   * emit of a dynamic ES `import()` from TypeScript.
-   */
-  private _makeLocalRequire(moduleMetaData: ModuleMetaData): AMDRequire {
-    return (
-      deps: ModuleSpecifier[],
-      callback: AmdCallback,
-      errback: AmdErrback
-    ): void => {
-      log("localRequire", deps);
-      assert(
-        deps.length === 1,
-        "Local require requires exactly one dependency."
-      );
-      const [moduleSpecifier] = deps;
-      try {
-        const requiredMetaData = this.run(
-          moduleSpecifier,
-          moduleMetaData.fileName
-        );
-        callback(requiredMetaData.exports);
-      } catch (e) {
-        errback(e);
-      }
-    };
-  }
-
   /** Given a `moduleSpecifier` and `containingFile` retrieve the cached
    * `fileName` for a given module.  If the module has yet to be resolved
    * this will return `undefined`.
@@ -468,32 +311,11 @@ export class DenoCompiler
     return moduleMetaData ? moduleMetaData.sourceMap : "";
   }
 
-  /** For a given module specifier and containing file, return a list of
-   * absolute identifiers for dependent modules that are required by this
-   * module.
-   */
-  getModuleDependencies(
-    moduleSpecifier: ModuleSpecifier,
-    containingFile: ContainingFile
-  ): ModuleFileName[] {
-    assert(
-      this._runQueue.length === 0,
-      "Cannot get dependencies with modules queued to be run."
-    );
-    const moduleMetaData = this.resolveModule(moduleSpecifier, containingFile);
-    assert(
-      !moduleMetaData.hasRun,
-      "Cannot get dependencies for a module that has already been run."
-    );
-    this._gatherDependencies(moduleMetaData);
-    const dependencies = this._runQueue.map(
-      moduleMetaData => moduleMetaData.moduleId
-    );
-    // empty the run queue, to free up references to factories we have collected
-    // and to ensure that if there is a further invocation of `.run()` the
-    // factories don't get called
-    this._runQueue = [];
-    return dependencies;
+  getOutput(filename: ModuleFileName): OutputCode {
+    const moduleMetaData = this.getModuleMetaData(filename)!;
+    assert(moduleMetaData != null, `Module not loaded: "${filename}"`);
+    this._scriptFileNames = [moduleMetaData.fileName];
+    return this.compile(moduleMetaData);
   }
 
   /** Given a `moduleSpecifier` and `containingFile`, resolve the module and
@@ -543,6 +365,7 @@ export class DenoCompiler
     }
     assert(moduleId != null, "No module ID.");
     assert(fileName != null, "No file name.");
+    assert(sourceCode ? sourceCode.length > 0 : false, "No source code.");
     assert(
       mediaType !== MediaType.Unknown,
       `Unknown media type for: "${moduleSpecifier}" from "${containingFile}".`
@@ -581,13 +404,23 @@ export class DenoCompiler
     this._log("compiler.run", { moduleSpecifier, containingFile });
     const moduleMetaData = this.resolveModule(moduleSpecifier, containingFile);
     this._scriptFileNames = [moduleMetaData.fileName];
-    if (!moduleMetaData.deps) {
-      this._gatherDependencies(moduleMetaData);
-    }
-    this._drainRunQueue();
     return moduleMetaData;
   }
 
+  getSource(filename: ModuleFileName): SourceCode {
+    const moduleMetaData = this.getModuleMetaData(filename)!;
+    assert(moduleMetaData != null, `Module not loaded: "${filename}"`);
+    return moduleMetaData.sourceCode;
+  }
+
+  getJavaScriptSource(filename: ModuleFileName): OutputCode {
+    let s = this.getOutput(filename);
+    if (!s) {
+      s = this.getSource(filename);
+    }
+    return s;
+  }
+
   // TypeScript Language Service and Format Diagnostic Host API
 
   getCanonicalFileName(fileName: string): string {
@@ -613,7 +446,7 @@ export class DenoCompiler
 
   getScriptKind(fileName: ModuleFileName): ts.ScriptKind {
     this._log("getScriptKind()", fileName);
-    const moduleMetaData = this._getModuleMetaData(fileName);
+    const moduleMetaData = this.getModuleMetaData(fileName);
     if (moduleMetaData) {
       switch (moduleMetaData.mediaType) {
         case MediaType.TypeScript:
@@ -632,13 +465,13 @@ export class DenoCompiler
 
   getScriptVersion(fileName: ModuleFileName): string {
     this._log("getScriptVersion()", fileName);
-    const moduleMetaData = this._getModuleMetaData(fileName);
+    const moduleMetaData = this.getModuleMetaData(fileName);
     return (moduleMetaData && moduleMetaData.scriptVersion) || "";
   }
 
   getScriptSnapshot(fileName: ModuleFileName): ts.IScriptSnapshot | undefined {
     this._log("getScriptSnapshot()", fileName);
-    return this._getModuleMetaData(fileName);
+    return this.getModuleMetaData(fileName);
   }
 
   getCurrentDirectory(): string {
@@ -664,7 +497,7 @@ export class DenoCompiler
   }
 
   fileExists(fileName: string): boolean {
-    const moduleMetaData = this._getModuleMetaData(fileName);
+    const moduleMetaData = this.getModuleMetaData(fileName);
     const exists = moduleMetaData != null;
     this._log("fileExists()", fileName, exists);
     return exists;
@@ -704,19 +537,6 @@ export class DenoCompiler
     });
   }
 
-  // Deno specific static properties and methods
-
-  /** Built in modules which can be returned to external modules
-   *
-   * Placed as a private static otherwise we get use before
-   * declared with the `DenoCompiler`
-   */
-  // tslint:disable-next-line:no-any
-  private static _builtins: { [mid: string]: any } = {
-    typescript: ts,
-    deno
-  };
-
   private static _instance: DenoCompiler | undefined;
 
   /** Returns the instance of `DenoCompiler` or creates a new instance. */