Implement the compiler API and use it in frog_leg.dart.

dart/frog/leg/frog_leg.dart

Index: dart/frog/leg/frog_leg.dart
diff --git a/dart/frog/leg/frog_leg.dart b/dart/frog/leg/frog_leg.dart
index c07aed4f5c625f569e7093ce1247f42db5b42173..b5a91274436d22ca63d6b403017e85270132783e 100644
--- a/dart/frog/leg/frog_leg.dart
+++ b/dart/frog/leg/frog_leg.dart
@@ -6,158 +6,46 @@
 
 #import('../../lib/uri/uri.dart');
 #import('../lang.dart', prefix: 'frog');
-#import('elements/elements.dart');
+#import('api.dart', prefix: 'api');
 #import('io/io.dart', prefix: 'io');
-#import('leg.dart');
-#import('tree/tree.dart');
-#import('ssa/tracer.dart');
 
 bool compile(frog.World world) {
   final throwOnError = frog.options.throwOnErrors;
-  final compiler = new WorldCompiler(world, throwOnError);
-  Uri cwd = new Uri(scheme: 'file', path: compiler.currentDirectory);
+  // final compiler = new WorldCompiler(world, throwOnError);
+  Uri cwd = new Uri(scheme: 'file', path: io.getCurrentDirectory());
   Uri uri = cwd.resolve(frog.options.dartScript);
-  return compiler.run(uri);
-}
-
-class WorldCompiler extends Compiler {
-  final frog.World world;
-  final bool throwOnError;
-
-  WorldCompiler(this.world, this.throwOnError)
-    : super.withCurrentDirectory(io.getCurrentDirectory(),
-                                 tracer: new HTracer());
-
-  void log(message) {
-    if (frog.options.showInfo) {
-      // Avoid calling message.toString() unless showInfo is on. It
-      // could be slow.
-      world.info('[leg] $message');
-    }
-  }
+  String frogLibDir = frog.options.libDir;
+  if (!frogLibDir.endsWith("/")) frogLibDir = "$frogLibDir/";
+  Uri frogLib = new Uri(scheme: 'file', path: frogLibDir);
+  Uri libraryRoot = frogLib.resolve('../leg/lib/');
 
-  bool run(Uri uri) {
-    bool success = super.run(uri);
-    if (success) {
-      var code = assembledCode;
-      world.legCode = code;
-      world.jsBytesWritten = code.length;
-      for (final task in tasks) {
-        log('${task.name} took ${task.timing}msec');
-      }
+  Future<String> provider(Uri uri) {
+    if (uri.scheme != 'file') {
+      throw new IllegalArgumentException(uri);
     }
-    return success;
+    String source = world.files.readAll(uri.path);
+    world.dartBytesRead += source.length;
+    Completer<String> completer = new Completer<String>();
+    completer.complete(source);
+    return completer.future;
   }
 
-  spanFromNode(Node node, Script current) {
-    final begin = node.getBeginToken();
-    final end = node.getEndToken();
-    if (begin === null || end === null) {
-      cancel('cannot find tokens to produce error message for $node.');
-    }
-    final startOffset = begin.charOffset;
-    // TODO(ahe): Compute proper end offset.
-    final endOffset = end.charOffset + 1;
-    return new frog.SourceSpan(current.file, startOffset, endOffset);
-  }
-
-  currentScript() {
-    if (currentElement === null) return null;
-    CompilationUnitElement compilationUnit =
-      currentElement.getCompilationUnit();
-    if (compilationUnit === null) return null;
-    return compilationUnit.script;
-  }
-
-  reportWarning(Node node, var message) {
-    frog.SourceSpan span;
-    Script current = currentScript();
-    if (current === null) {
-      world.fatal('No current script');
-    } else if (node === null) {
-      span = new frog.SourceSpan(current.file, 0, 0);
-    } else {
-      span = spanFromNode(node, current);
-    }
-    world.warning('$message.', span);
-  }
-
-  reportError(Node node, var message) {
-    cancel(message.toString(), node);
-  }
-
-  Uri getUriFor(String fileName) {
-    Uri cwd = new Uri(scheme: 'file', path: currentDirectory);
-    return cwd.resolve(fileName);
-  }
-
-  Script readScript(Uri uri, [ScriptTag node]) {
-    String uriName = uri.toString();
-    // TODO(ahe): Clean this up.
-    if (uriName == 'dart:dom') {
-      uri = getUriFor(io.join([legDirectory, '..', '..',
-          'client', 'dom', 'frog', 'dom_frog.dart']));
-    } else if (uriName == 'dart:html') {
-      uri = getUriFor(io.join([legDirectory, '..', '..',
-          'client', 'html', 'frog', 'html_frog.dart']));
-    } else if (uriName == 'dart:json') {
-      uri = getUriFor(io.join([legDirectory, '..', '..',
-          'lib', 'json', 'json.dart']));
-    }
-    if (uri.scheme != 'file') cancel('cannot read $uri', node: node);
-    String text = "";
-    try {
-      text = frog.world.files.readAll(uri.path);
-    } catch (var exception) {
-      cancel("${uri.path}: $exception", node: node);
-    }
-    world.dartBytesRead += text.length;
-    frog.SourceFile sourceFile = new frog.SourceFile(uri.toString(), text);
-    return new Script(uri, sourceFile);
-  }
-
-  String get legDirectory() => io.join([frog.options.libDir, '..', 'leg']);
-
-  void cancel([String reason, Node node, token, instruction, element]) {
-    Script script = currentScript();
-    if (node !== null) {
-      print(spanFromNode(node, script).toMessageString("cancel leg: $reason"));
-    } else if (token !== null) {
-      int begin = token.charOffset;
-      int end = begin + 1; // TODO(ahe): Compute proper length.
-      print(script.file.getLocationMessage("cancel leg: $reason",
-                                           begin, end, true));
-    } else if (element !== null) {
-      if (element.position() === null) {
-        // Sometimes, the backend fakes up elements that have no
-        // position. So we use the enclosing element instead. It is
-        // not a good error location, but cancel really is "internal
-        // error" or "not implemented yet", so the vicinity is good
-        // enough for now.
-        element = element.enclosingElement;
-        // TODO(ahe): I plan to overhaul this infrastructure anyways.
-      }
-      if (element !== null) {
-        withCurrentElement(element,
-            () => cancel(reason: reason, token: element.position()));
-      }
-    } else if (currentElement !== null) {
-      cancel(reason, element: currentElement);
+  void handler(Uri uri, int begin, int end, String message, bool fatal) {
+    if (uri === null && !fatal) {
+      world.info('[leg] $message');
       return;
     }
-    if (throwOnError) {
-      throw new AbortLeg(reason);
-    }
-    super.cancel(reason, node, token, instruction);
+    print(message);
+    if (fatal && throwOnError) new AbortLeg(message);
   }
 
-  LibraryElement scanBuiltinLibrary(String filename) {
-    String fileName = io.join([legDirectory, 'lib', filename]);
-    Uri cwd = new Uri(scheme: 'file', path: currentDirectory);
-    Uri uri = cwd.resolve(fileName);
-    LibraryElement library = scanner.loadLibrary(uri, null);
-    return library;
-  }
+  // TODO(ahe): We expect the future to be complete and call value
+  // directly. In effect, we don't support truly asynchronous API.
+  String code = api.compile(uri, libraryRoot, provider, handler).value;
+  if (code === null) return false;
+  world.legCode = code;
+  world.jsBytesWritten = code.length;
+  return true;
 }
 
 class AbortLeg {