leg pad (similar to frogpad, but for leg)

tools/testing/legpad/legpad.dart

Index: tools/testing/legpad/legpad.dart
diff --git a/tools/testing/legpad/legpad.dart b/tools/testing/legpad/legpad.dart
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+++ b/tools/testing/legpad/legpad.dart
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+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#import("dart:html", prefix:"html");
+#import('../../../frog/leg/api.dart', prefix: "api_lib");
+#import('../../../lib/uri/uri.dart', prefix:"uri_lib");
+
+/**
+ * This is the entrypoint for a version of the leg compiler that
+ * runs in the browser.
+ *
+ * Because this is running in the browser, we do not access
+ * the file system.  Instead, we assume that all necessary files
+ * have been placed in inert <script> elements somewhere on the html page.
+ *
+ * (See legpad.py for more details on how the html page is constructed.)
+ */
+void main() {
+  new Legpad().run();
+}
+
+class Legpad {
+  // id of script element containing name of the main dart file
+  // to compile
+  static final String MAIN_ID = "main_id";
+  
+  Legpad() : warnings = new StringBuffer();
+
+  // accumulates diagnostic messages emitted by the leg compiler
+  StringBuffer warnings;
+
+  // the generated javascript
+  String output;
+
+  String readAll(String filename) {
+    String text = getText(idOfFilename(filename));
+    print("read $filename (${text.length} bytes)");
+    return text;
+  }
+
+  void diagnosticHandler(uri_lib.Uri uri, int begin, int end,
+                                 String message, bool fatal) {
+    // TODO(mattsh): format message with location info
+    warnings.add(message).add("\n");
+  }
+
+  Future<String> readUriFromString(uri_lib.Uri uri) {
+    Completer<String> completer = new Completer<String>();
+    completer.complete(readAll(uri.toString()));
+    return completer.future;
+  }
+
+  /**
+   * Returns the id of the <script> element that contains
+   * the contents of this file.  (Replace all slashes
+   * and dots in the file name with underscores.)
+   */
+  String idOfFilename(String filename) {
+    return filename.replaceAll("/", "_").replaceAll(".", "_");
+  }
+
+  void run() {
+    String mainFile = getText(MAIN_ID);
+    setText("input", readAll(mainFile));
+    Stopwatch stopwatch = new Stopwatch.start();    
+    runLeg();
+    int elapsedMillis = stopwatch.elapsedInMs();
+    setText("output", output);
+    setText("warnings", warnings);
+    String timing = "generated ${output.length} characters in " +
+        "${((elapsedMillis) / 1000).toStringAsPrecision(3)} seconds";
+    setText("timing", timing);
+  }
+
+  void runLeg() {
+    uri_lib.Uri mainUri = new uri_lib.Uri.fromString(getText(MAIN_ID));
+    uri_lib.Uri libraryRoot = 
+        new uri_lib.Uri.fromString("dartdir/frog/leg/lib/");
+    List<String> compilerArgs = [
+      "--enable_type_checks",
+      "--enable_asserts"
+    ];
+    
+    // TODO(mattsh) - dart2js api should be synchronous
+    Future<String> futureJavascript = api_lib.compile(mainUri,
+         libraryRoot, readUriFromString, diagnosticHandler, compilerArgs);
+    
+    if (futureJavascript == null) {
+      output = "throw 'legpad compilation error';\n";
+      return;
+    } 
+    output = futureJavascript.value;
+  }
+
+  void setText(String id, String text) {
+    html.Element element = html.document.query("#$id");
+    if (element === null) {
+      throw new Exception("Can't find element $id");
+    }
+    element.innerHTML = htmlEscape(text);
+  }
+
+  String getText(String id) {
+    html.Element element = html.document.query("#$id");
+    if (element === null) {
+      throw new Exception("Can't find element $id");
+    }
+    return element.text.trim();
+  }
+
+  // TODO(mattsh): should exist in standard lib somewhere
+  static String htmlEscape(String text) {
+    return text.replaceAll('&', '&amp;').replaceAll(
+        '>', '&gt;').replaceAll('<', '&lt;');
+  }
+}