Support source maps in server mode

lib/src/codegen/js_printer.dart

Index: lib/src/codegen/js_printer.dart
diff --git a/lib/src/codegen/js_printer.dart b/lib/src/codegen/js_printer.dart
index 021678f2a59e5603865adcc7659222a26600f170..945c1563e80726169a47a1dce5ac8131c68257e9 100644
--- a/lib/src/codegen/js_printer.dart
+++ b/lib/src/codegen/js_printer.dart
@@ -18,7 +18,8 @@ import '../utils.dart' show computeHash, locationForOffset;
 
 import 'js_names.dart' show TemporaryNamer;
 
-String writeJsLibrary(JS.Program jsTree, String outputPath,
+String writeJsLibrary(JS.Program jsTree, String outputPath, String inputDir,
+    String serverUrl,
     {bool emitSourceMaps: false, bool arrowFnBindThisWorkaround: false}) {
   var outFilename = path.basename(outputPath);
   var outDir = path.dirname(outputPath);
@@ -27,7 +28,7 @@ String writeJsLibrary(JS.Program jsTree, String outputPath,
   JS.JavaScriptPrintingContext context;
   if (emitSourceMaps) {
     var printer = new srcmaps.Printer(outFilename);
-    context = new SourceMapPrintingContext(printer, outDir);
+    context = new SourceMapPrintingContext(printer, outDir, inputDir, serverUrl);
   } else {
     context = new JS.SimpleJavaScriptPrintingContext();
   }
@@ -72,11 +73,13 @@ String writeJsLibrary(JS.Program jsTree, String outputPath,
 class SourceMapPrintingContext extends JS.JavaScriptPrintingContext {
   final srcmaps.Printer printer;
   final String outputDir;
+  final String inputDir;
+  final String serverUrl;
 
   CompilationUnit unit;
   Uri uri;
 
-  SourceMapPrintingContext(this.printer, this.outputDir);
+  SourceMapPrintingContext(this.printer, this.outputDir, this.inputDir, this.serverUrl);

[Jennifer Messerly, 2015/12/16 18:40:07]

slight factoring thing, I wonder if we should pass in something that can do URI
mapping for us (AbstractCompiler?), rather than have SourceMapPrintingContext
know about server details?

I've been slowly trying to disentangle server from the rest of the code base, in
the hopes that we can remove it in favor of a file watcher as the primary dev
experience.

[vsm, 2016/01/07 21:22:03]

added a todo

 
   void emit(String string) {
     printer.add(string);
@@ -95,6 +98,7 @@ class SourceMapPrintingContext extends JS.JavaScriptPrintingContext {
       unit = node.getAncestor((n) => n is CompilationUnit);
       uri = _makeRelativeUri(unit.element.source.uri);
     }
+    if (unit == null) return;
 
     assert(unit != null);
     var loc = _location(node.offset);
@@ -113,7 +117,15 @@ class SourceMapPrintingContext extends JS.JavaScriptPrintingContext {
       locationForOffset(unit.lineInfo, uri, offset);
 
   Uri _makeRelativeUri(Uri src) {
-    return new Uri(path: path.relative(src.path, from: outputDir));
+    if (serverUrl == null) {
+      return new Uri(path: path.relative(src.path, from: outputDir));
+    } else {
+      if (src.path.startsWith('/')) {
+        return new Uri(path: serverUrl + path.relative(src.path, from: inputDir));

[Jennifer Messerly, 2015/12/16 18:40:07]

the name here's a little confusing, if this was a full "serverUrl" I don't think
it would make sense to put it in the "path" part of the Uri. I guess it's the
"servePath", e.g. if server Url is http://localhost:8080/foo/bar, this is the
"foo/bar/" part?

[vsm, 2016/01/07 21:22:03]

i think i was abusing the path argument to the Uri constructor.  redid this more
cleanly.

+      } else {
+        return new Uri(path: serverUrl + 'packages/' + src.path);
+      }
+    }
   }
 
   void exitNode(JS.Node jsNode) {