Custom formatter cleanup Fix case where displaying a class constructor generated unreadable huge ou…

pkg/dev_compiler/lib/src/compiler/code_generator.dart

Index: pkg/dev_compiler/lib/src/compiler/code_generator.dart
diff --git a/pkg/dev_compiler/lib/src/compiler/code_generator.dart b/pkg/dev_compiler/lib/src/compiler/code_generator.dart
index 24aac39abbdb4c5e7b1c3bd363f5bee5d8bb218b..6b8a2ca65ae86d6a04ab558a71df4ba1b8911ef8 100644
--- a/pkg/dev_compiler/lib/src/compiler/code_generator.dart
+++ b/pkg/dev_compiler/lib/src/compiler/code_generator.dart
@@ -191,7 +191,7 @@ class CodeGenerator extends GeneralizingAstVisitor
       _libraryRoot += separator;
     }
 
-    var module = _emitModule(compilationUnits);
+    var module = _emitModule(compilationUnits, unit.name);
     var dartApiSummary = _summarizeModule(compilationUnits);
 
     return new JSModuleFile(unit.name, errors, options, module, dartApiSummary);
@@ -237,7 +237,7 @@ class CodeGenerator extends GeneralizingAstVisitor
     return bundle.toBuffer();
   }
 
-  JS.Program _emitModule(List<CompilationUnit> compilationUnits) {
+  JS.Program _emitModule(List<CompilationUnit> compilationUnits, String name) {
     if (_moduleItems.isNotEmpty) {
       throw new StateError('Can only call emitModule once.');
     }
@@ -320,6 +320,11 @@ class CodeGenerator extends GeneralizingAstVisitor
     // hoisted definitions.
     items.addAll(_typeTable.discharge());
 
+    // Track the module name for each library in the module.
+    // This data is only required for debugging.
+    _moduleItems.add(js.statement('#.trackLibraries(#, #);',
+        [_runtimeModule, js.string(name), _librariesDebuggerObject()]));
+
     // Add the module's code (produced by visiting compilation units, above)
     _copyAndFlattenBlocks(items, _moduleItems);
 
@@ -327,6 +332,17 @@ class CodeGenerator extends GeneralizingAstVisitor
     return new JS.Program(items, name: _buildUnit.name);
   }
 
+  JS.ObjectInitializer _librariesDebuggerObject() {
+    var properties = <JS.Property>[];
+    _libraries.forEach((library, value) {
+      // TODO(jacobr): we could specify a short library name instead of the
+      // full library uri if we wanted to save space.
+      properties.add(new JS.Property(
+          js.string(jsLibraryDebuggerName(_libraryRoot, library)), value));
+    });
+    return new JS.ObjectInitializer(properties);
+  }
+
   List<String> _getJSName(Element e) {
     if (e.library == null ||
         findAnnotation(e.library, isPublicJSAnnotation) == null) {
@@ -457,6 +473,7 @@ class CodeGenerator extends GeneralizingAstVisitor
         imports.add(new JS.NameSpecifier(_runtimeModule));
         imports.add(new JS.NameSpecifier(_extensionSymbolsModule));
       }
+
       items.add(new JS.ImportDeclaration(
           namedImports: imports, from: js.string(module, "'")));
     });
@@ -5853,6 +5870,44 @@ String jsLibraryName(String libraryRoot, LibraryElement library) {
   return pathToJSIdentifier(qualifiedPath);
 }
 
+/// Debugger friendly name for a Dart Library.
+String jsLibraryDebuggerName(String libraryRoot, LibraryElement library) {
+  var uri = library.source.uri;
+  // For package: and dart: uris show the entire
+  if (uri.scheme == 'dart' || uri.scheme == 'package') return uri.toString();
+
+  if (!uri.toFilePath().startsWith(libraryRoot)) {
+    throw 'Invalid library root. $libraryRoot does not contain ${uri
+        .toFilePath()}';
+  }
+  // Relative path to the library.
+  return uri.path.substring(libraryRoot.length);
+}
+
+String jsDebuggingLibraryName(String libraryRoot, LibraryElement library) {
+  var uri = library.source.uri;
+  if (uri.scheme == 'dart') {
+    return uri.path;
+  }
+  // TODO(vsm): This is not necessarily unique if '__' appears in a file name.
+  var separator = '__';
+  String qualifiedPath;
+  if (uri.scheme == 'package') {
+    // Strip the package name.
+    // TODO(vsm): This is not unique if an escaped '/'appears in a filename.
+    // E.g., "foo/bar.dart" and "foo$47bar.dart" would collide.
+    qualifiedPath = uri.pathSegments.skip(1).join(separator);
+  } else if (uri.toFilePath().startsWith(libraryRoot)) {
+    qualifiedPath =
+        uri.path.substring(libraryRoot.length).replaceAll('/', separator);
+  } else {
+    // We don't have a unique name.
+    throw 'Invalid library root. $libraryRoot does not contain ${uri
+        .toFilePath()}';
+  }
+  return pathToJSIdentifier(qualifiedPath);
+}
+
 /// Shorthand for identifier-like property names.
 /// For now, we emit them as strings and the printer restores them to
 /// identifiers if it can.