Handle local files better in server mode

We're already serving sources from the original directory (for source
maps).  This lets us serve other resources as well.  Makes it simpler
to run angular todo and other apps with xhr'ed data.

[email protected]

Review URL: https://codereview.chromium.org/1644673002 .

Author: vsmenon

pkg/dev_compiler/lib/src/server/server.dart

@@ -254,17 +254,20 @@ class DevServer {
     var out = new Directory(outDir);
     if (!await out.exists()) await out.create(recursive: true);
 
-    var mainHandler =
+    var generatedHandler =
         shelf_static.createStaticHandler(outDir, defaultDocument: _entryPath);
     var sourceHandler = shelf_static.createStaticHandler(compiler.inputBaseDir,
         serveFilesOutsidePath: true);
+    // TODO(vsm): Is there a better builtin way to compose these handlers?
     var topLevelHandler = (shelf.Request request) {
       var path = request.url.path;
-      if (path.endsWith('.dart')) {
-        return sourceHandler(request);
-      } else {
-        return mainHandler(request);
+      // Prefer generated code
+      var response = generatedHandler(request);
+      if (response.statusCode == 404) {
+        // Fall back on original sources
+        response = sourceHandler(request);
       }
+      return response;
     };
 
     var handler = const shelf.Pipeline()

pkg/dev_compiler/test/codegen/expect/collection/src/unmodifiable_wrappers.txt

@@ -1,5 +1,5 @@
 // Messages from compiling unmodifiable_wrappers.dart
-severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.map' and 'Iterable.expand' (package:collection/src/unmodifiable_wrappers.dart, line 33, col 7)
+severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand' and 'Iterable.map' (package:collection/src/unmodifiable_wrappers.dart, line 33, col 7)
 severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand' and 'Iterable.map' (package:collection/src/unmodifiable_wrappers.dart, line 136, col 7)
 warning: [DOWN_CAST_COMPOSITE] _throw() (dynamic) will need runtime check to cast to type E (package:collection/src/unmodifiable_wrappers.dart, line 88, col 28)
 warning: [DOWN_CAST_COMPOSITE] _throw() (dynamic) will need runtime check to cast to type E (package:collection/src/unmodifiable_wrappers.dart, line 94, col 21)

pkg/dev_compiler/test/codegen/expect/collection/wrappers.txt

@@ -4,14 +4,14 @@ severe: [INVALID_METHOD_OVERRIDE] Invalid override. The type of _DelegatingItera
 severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand' and 'Iterable.map' (package:collection/wrappers.dart, line 117, col 7)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.expand (((E) → Iterable<dynamic>) → Iterable<dynamic>) is not a subtype of Iterable<E>.expand (<T>((E) → Iterable<T>) → Iterable<T>). (package:collection/wrappers.dart, line 117, col 25)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.map (((E) → dynamic) → Iterable<dynamic>) is not a subtype of Iterable<E>.map (<T>((E) → T) → Iterable<T>). (package:collection/wrappers.dart, line 117, col 25)
-severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.map' and 'Iterable.expand' (package:collection/wrappers.dart, line 216, col 7)
+severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand' and 'Iterable.map' (package:collection/wrappers.dart, line 216, col 7)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.expand (((E) → Iterable<dynamic>) → Iterable<dynamic>) is not a subtype of Iterable<E>.expand (<T>((E) → Iterable<T>) → Iterable<T>). (package:collection/wrappers.dart, line 216, col 24)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.map (((E) → dynamic) → Iterable<dynamic>) is not a subtype of Iterable<E>.map (<T>((E) → T) → Iterable<T>). (package:collection/wrappers.dart, line 216, col 24)
-severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.map' and 'Iterable.expand' (package:collection/wrappers.dart, line 269, col 7)
+severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand' and 'Iterable.map' (package:collection/wrappers.dart, line 269, col 7)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.expand (((E) → Iterable<dynamic>) → Iterable<dynamic>) is not a subtype of Iterable<E>.expand (<T>((E) → Iterable<T>) → Iterable<T>). (package:collection/wrappers.dart, line 269, col 26)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.map (((E) → dynamic) → Iterable<dynamic>) is not a subtype of Iterable<E>.map (<T>((E) → T) → Iterable<T>). (package:collection/wrappers.dart, line 269, col 26)
 severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand' and 'Iterable.map' (package:collection/wrappers.dart, line 367, col 7)
-severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.expand' and 'Iterable.map' (package:collection/wrappers.dart, line 452, col 7)
+severe: [AnalyzerMessage] Missing concrete implementation of 'Iterable.map' and 'Iterable.expand' (package:collection/wrappers.dart, line 452, col 7)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.expand (((V) → Iterable<dynamic>) → Iterable<dynamic>) is not a subtype of Iterable<V>.expand (<T>((V) → Iterable<T>) → Iterable<T>). (package:collection/wrappers.dart, line 452, col 25)
 severe: [INVALID_METHOD_OVERRIDE] Base class introduces an invalid override. The type of _DelegatingIterableBase.map (((V) → dynamic) → Iterable<dynamic>) is not a subtype of Iterable<V>.map (<T>((V) → T) → Iterable<T>). (package:collection/wrappers.dart, line 452, col 25)
 warning: [DOWN_CAST_COMPOSITE] _base.fold(initialValue, combine) (dynamic) will need runtime check to cast to type T (package:collection/wrappers.dart, line 49, col 7)