Extend compiler API to support multiple outputs.

dart/sdk/lib/_internal/compiler/implementation/dart2js.dart

Index: dart/sdk/lib/_internal/compiler/implementation/dart2js.dart
diff --git a/dart/sdk/lib/_internal/compiler/implementation/dart2js.dart b/dart/sdk/lib/_internal/compiler/implementation/dart2js.dart
index 62286a07529c38c2a4dd5c804a6ba73332ec3c3b..dc7b2574c2e0f56b9feb83b43916cac132856d21 100644
--- a/dart/sdk/lib/_internal/compiler/implementation/dart2js.dart
+++ b/dart/sdk/lib/_internal/compiler/implementation/dart2js.dart
@@ -198,7 +198,7 @@ void compile(List<String> argv) {
   Map<String, SourceFile> sourceFiles = <String, SourceFile>{};
   int dartBytesRead = 0;
 
-  Future<String> provider(Uri uri) {
+  Future<String> inputProvider(Uri uri) {
     if (uri.scheme != 'file') {
       throw new ArgumentError(uri);
     }
@@ -232,13 +232,6 @@ void compile(List<String> argv) {
 
   void handler(Uri uri, int begin, int end, String message,
                api.Diagnostic kind) {
-    if (identical(kind.name, 'source map')) {
-      // TODO(podivilov): We should find a better way to return source maps from
-      // emitter. Using diagnostic handler for that purpose is a temporary hack.
-      writeString(sourceMapOut, message);
-      return;
-    }
-
     if (isAborting) return;
     isAborting = identical(kind, api.Diagnostic.CRASH);
     bool fatal = (kind.ordinal & FATAL) != 0;
@@ -286,26 +279,60 @@ void compile(List<String> argv) {
 
   info('package root is $packageRoot');
 
-  // TODO(ahe): We expect the future to be complete and call value
-  // directly. In effect, we don't support truly asynchronous API.
-  String code = deprecatedFutureValue(
-      api.compile(uri, libraryRoot, packageRoot, provider, handler, options));
-  if (code == null) {
-    fail('Error: Compilation failed.');
+  compilationDone(String code) {
+    if (code == null) {
+      fail('Error: Compilation failed.');
+    }
+    writeString(new Uri.fromString('$out.deps'), getDepsOutput(sourceFiles));
+    int bytesWritten = code.length;
+    info('compiled $dartBytesRead bytes Dart -> $bytesWritten bytes '
+         '$outputLanguage in ${relativize(cwd, out, isWindows)}');
+    if (!explicitOut) {
+      String input = uriPathToNative(arguments[0]);
+      String output = relativize(cwd, out, isWindows);
+      print('Dart file $input compiled to $outputLanguage: $output');
+    }
   }
-  String sourceMapFileName =
-      sourceMapOut.path.substring(sourceMapOut.path.lastIndexOf('/') + 1);
-  code = '$code\n//@ sourceMappingURL=${sourceMapFileName}';
-  writeString(out, code);
-  writeString(new Uri.fromString('$out.deps'), getDepsOutput(sourceFiles));
-  int bytesWritten = code.length;
-  info('compiled $dartBytesRead bytes Dart -> $bytesWritten bytes '
-       '$outputLanguage in ${relativize(cwd, out, isWindows)}');
-  if (!explicitOut) {
-    String input = uriPathToNative(arguments[0]);
-    String output = relativize(cwd, out, isWindows);
-    print('Dart file $input compiled to $outputLanguage: $output');
+
+  Sink<String> outputProvider(String name, String extension) {
+    Uri uri;
+    String sourceMapFileName;
+    if (name == '') {
+      if (extension == 'js' || extension == 'dart') {
+        uri = out;
+        sourceMapFileName =
+            sourceMapOut.path.substring(sourceMapOut.path.lastIndexOf('/') + 1);
+      } else if (extension == 'js.map' || extension == 'dart.map') {
+        uri = sourceMapOut;
+      } else {
+        fail('Error: Unknown extension: $extension');
+      }
+    } else {
+      uri = out.resolve('$name.$extension');
+    }
+
+    if (uri.scheme != 'file') {
+      fail('Error: Unhandled scheme ${uri.scheme} in $uri.');
+    }
+    var outputStream = new File(uriPathToNative(uri.path)).openOutputStream();
+
+    onDone() {
+      if (sourceMapFileName != null) {
+        outputStream.writeString('//@ sourceMappingURL=');
+        outputStream.writeString(sourceMapFileName);
+        outputStream.writeString('\n');
+      }
+      outputStream.close();
+    }
+
+    return new StreamController<String>()
+        ..listen(outputStream.writeString, onDone: onDone);
   }
+
+  api.compile(uri, libraryRoot, packageRoot,
+              inputProvider, handler,
+              options, outputProvider)
+      .then(compilationDone);
 }
 
 class AbortLeg {