Support for specifying an output directory (issue #106)

lib/src/emitters.dart

Index: lib/src/emitters.dart
diff --git a/lib/src/emitters.dart b/lib/src/emitters.dart
index 51e767d286e32d3af311d8b058e208b8607cf4df..a415a498bfabfbcf38e1fb70fed2cb15d843c447 100644
--- a/lib/src/emitters.dart
+++ b/lib/src/emitters.dart
@@ -13,9 +13,10 @@ import 'package:html5lib/dom_parsing.dart';
 
 import 'code_printer.dart';
 import 'codegen.dart' as codegen;
-import 'messages.dart';
+import 'file_system/path.dart';
 import 'files.dart';
 import 'info.dart';
+import 'messages.dart';
 
 /**
  * An emitter for a web component feature.  It collects all the logic for
@@ -527,7 +528,7 @@ class RecursiveEmitter extends TreeVisitor {
 class WebComponentEmitter extends RecursiveEmitter {
   WebComponentEmitter(FileInfo info) : super(info);
 
-  String run(ComponentInfo info) {
+  String run(ComponentInfo info, PathInfo pathInfo) {
     // If this derives from another component, ensure the lifecycle methods are
     // called in the superclass.
     if (info.extendsComponent != null) {
@@ -561,45 +562,43 @@ class WebComponentEmitter extends RecursiveEmitter {
 
     visit(info.element);
 
-    var code = info.userCode;
-    if (code == null) {
-      if (info.extendsComponent != null) {
-        var superclass = info.extendsComponent.constructor;
-        // TODO(jmesserly): should we add this import even if you have your own
-        // script tag?
-        var relativePath = PathInfo.relativePath(info, info.extendsComponent);
-        code = '''
-          ${codegen.importList([relativePath])}
-          class ${info.constructor} extends $superclass {\n}
-        ''';
-      } else {
-        code = '''
-          import 'package:web_components/web_component.dart' as autogenerated;
-          class ${info.constructor} extends autogenerated.WebComponent {\n}
-        ''';
-      }
+    bool hasExtends = info.extendsComponent != null;
+    var codeInfo = info.userCode;
+    if (codeInfo == null) {
+      var superclass = hasExtends ? info.extendsComponent.constructor
+          : 'autogenerated.WebComponent';
+      var imports = hasExtends ? [] : [new DartDirectiveInfo('import',
+          'package:web_components/web_component.dart', 'autogenerated')];
+      codeInfo = new DartCodeInfo(null, null, imports,
+          'class ${info.constructor} extends $superclass {\n}');
     }
+
+    var code = codeInfo.code;
     var match = new RegExp('class ${info.constructor}[^{]*{').firstMatch(code);
     if (match != null) {
-      // TODO(sigmund): clean up and make this more robust. Issue #59.
       var printer = new CodePrinter();
-      var libMatch = const RegExp('^library .*;').firstMatch(code);
-      int startPos = 0;
-      if (libMatch == null) {
-        var libraryName = info.tagName.replaceAll(const RegExp('[-./]'), '_');
-        printer.add(codegen.header(info.declaringFile.path, libraryName));
-      } else {
-        printer.add('// Generated from ${info.inputPath.filename}\n'
-            '// DO NOT EDIT.');
-        printer.add(code.substring(0, libMatch.end()));
-        printer.add(codegen.imports);
-        startPos = libMatch.end();
+      var libraryName = (codeInfo.libraryName != null)
+          ? codeInfo.libraryName
+          : info.tagName.replaceAll(const RegExp('[-./]'), '_');
+      printer.add(codegen.header(info.declaringFile.path, libraryName));
+
+      // Add exisitng import, export, and part directives.
+      for (var directive in codeInfo.directives) {
+        printer.add(codegen.directiveText(directive, info, pathInfo));
       }
-      // Import only those components used by this component.
+
+      // Add imports only for those components used by this component.
       var imports = info.usedComponents.getKeys().map(
           (c) => PathInfo.relativePath(info, c));
+
+      if (hasExtends) {
+        // Inject an import to the base component.
+        printer.add(codegen.importList(
+            [PathInfo.relativePath(info, info.extendsComponent)]));
+      }
+
       printer.add(codegen.importList(imports))
-          .add(code.substring(startPos, match.end()))
+          .add(code.substring(0, match.end()))
           .add('\n')
           .add(codegen.componentCode(info.constructor,
               _context.declarations.formatString(1),
@@ -612,7 +611,7 @@ class WebComponentEmitter extends RecursiveEmitter {
       messages.error('please provide a class definition '
           'for ${info.constructor}:\n $code', info.element.span,
           file: info.inputPath);
-      return code;
+      return '';
     }
   }
 }
@@ -621,35 +620,46 @@ class WebComponentEmitter extends RecursiveEmitter {
 class MainPageEmitter extends RecursiveEmitter {
   MainPageEmitter(FileInfo info) : super(info);
 
-  String run(Document document) {
+  String run(Document document, PathInfo pathInfo) {
     // The body of an element tag will not be part of the main HTML page. Each
     // element will be generated programatically as a dart web component by
     // [WebComponentEmitter] above.
     document.queryAll('element').forEach((tag) => tag.remove());
+
+    // fix up the URLs to content that is not modified by the compiler
+    document.queryAll('script').forEach((tag) {
+      var src = tag.attributes["src"];
+      if (tag.attributes['type'] != 'application/dart' && src != null) {
+        tag.attributes["src"] = pathInfo.transferDirectiveUrl(_info, src);
+      }
+    });
+    document.queryAll('link').forEach((tag) {
+      var href = tag.attributes['href'];
+      if (tag.attributes['rel'] != 'components' && href != null) {
+        tag.attributes['href'] = pathInfo.transferDirectiveUrl(_info, href);
+      }
+    });
+
     visit(document);
 
     var printer = new CodePrinter();
-    var startPos = 0;
 
     // Inject library name if not pressent.
-    // TODO(sigmund): consider parsing the top-level syntax of a dart file
-    // instead of this ad-hoc regex (issue #95).
-    var code = _info.userCode;
-    var match = const RegExp('^library .*;').firstMatch(code);
-    if (match == null) {
-      printer.add(codegen.header(_info.path, _info.libraryName));
-    } else {
-      printer.add('// Generated from ${_info.inputPath}\n// DO NOT EDIT.')
-          .add(code.substring(0, match.end()))
-          .add(codegen.imports);
-      startPos = match.end();
+    var codeInfo = _info.userCode;
+    var libraryName = codeInfo.libraryName != null
+        ? codeInfo.libraryName : _info.libraryName;
+    printer.add(codegen.header(_info.path, libraryName));
+
+    // Add exisitng import, export, and part directives.
+    for (var directive in codeInfo.directives) {
+      printer.add(codegen.directiveText(directive, _info, pathInfo));
     }
 
     // Import only those components used by the page.
     var imports = _info.usedComponents.getKeys().map(
           (c) => PathInfo.relativePath(_info, c));
     printer.add(codegen.importList(imports))
-        .add(codegen.mainDartCode(code.substring(startPos),
+        .add(codegen.mainDartCode(codeInfo.code,
             _context.declarations.formatString(0),
             _context.createdMethod.formatString(1),
             _context.insertedMethod.formatString(1),