Read SDK and patches from a JSON file.

pkg/front_end/lib/src/fasta/translate_uri.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library fasta.translate_uri;
 
 import 'dart:async' show Future;
 
-import 'package:front_end/file_system.dart';
+import 'dart:convert' show JSON;
+
+import 'package:front_end/file_system.dart'
+    show FileSystem, FileSystemException;
+
 import 'package:package_config/packages_file.dart' as packages_file show parse;
 
 import 'errors.dart' show inputError;
 
 class TranslateUri {
   final Map<String, Uri> packages;
   final Map<String, Uri> dartLibraries;
+  final Map<String, List<Uri>> patches;

[Siggi Cherem (dart-lang), 2017/05/22 16:21:15]

BTW - I pinged Siva on Friday to see if we can change the VM's representation of
patches: I'd really like to have a single library Uri rather than a list of
files for this (like we do in dart2js).

[ahe, 2017/05/22 16:26:47]

Agreed.

 
-  TranslateUri(this.packages, this.dartLibraries);
+  TranslateUri(this.packages, this.dartLibraries, this.patches);
 
   Uri translate(Uri uri) {
     if (uri.scheme == "dart") return translateDartUri(uri);
     if (uri.scheme == "package") return translatePackageUri(uri);
     return null;
   }
 
-  Uri translateDartUri(Uri uri) {
-    if (!uri.isScheme('dart')) return null;
-    String path = uri.path;
-
-    int index = path.indexOf('/');
-    if (index == -1) return dartLibraries[path];
-
-    String libraryName = path.substring(0, index);
-    String relativePath = path.substring(index + 1);
-    Uri libraryFileUri = dartLibraries[libraryName];
-    return libraryFileUri?.resolve(relativePath);
-  }
+  Uri translateDartUri(Uri uri) => dartLibraries[uri.path];

[Siggi Cherem (dart-lang), 2017/05/22 16:21:15]

Let's document the invariant that you told me about on Friday. Also, I'm
guessing we need to fix where Konstantin relied on the other behavior.

I can take on it separately if you prefer, in which case temporarily keep the
other behavior until we fix the use site.

[ahe, 2017/05/22 16:26:47]

I'll take a further look at this.

[ahe, 2017/05/24 16:09:46]

Let's go with the analyzer's approach. Personally, I have a strong preference
against implementing special rules for URI resolution. However, as long as we
keep them internal, it should matter.

 
   Uri translatePackageUri(Uri uri) {
     int index = uri.path.indexOf("/");
     if (index == -1) return null;
     String name = uri.path.substring(0, index);
     String path = uri.path.substring(index + 1);
     Uri root = packages[name];
     if (root == null) return null;
     return root.resolve(path);
   }
 
   static Future<TranslateUri> parse(FileSystem fileSystem, Uri sdk,
-      [Uri uri]) async {
-    // This list below is generated with [bin/generate_dart_libraries.dart] and
-    // additional entries for _builtin, _vmservice, profiler, and vmservice_io.
-    //
-    // TODO(ahe): This is only used with the option --compile-sdk, and
-    // currently doesn't work outside the SDK source tree.
-    Map<String, Uri> dartLibraries = <String, Uri>{};
-    if (sdk != null) {
-      dartLibraries = <String, Uri>{
-        "_async_await_error_codes": sdk.resolve(
-            "lib/_internal/js_runtime/lib/shared/async_await_error_codes.dart"),
-        "_blink": sdk.resolve("lib/_blink/dartium/_blink_dartium.dart"),
-        "_builtin": sdk.resolve("lib/_builtin/_builtin.dart"),
-        "_chrome": sdk.resolve("lib/_chrome/dart2js/chrome_dart2js.dart"),
-        "_foreign_helper":
-            sdk.resolve("lib/_internal/js_runtime/lib/foreign_helper.dart"),
-        "_interceptors":
-            sdk.resolve("lib/_internal/js_runtime/lib/interceptors.dart"),
-        "_internal": sdk.resolve("lib/internal/internal.dart"),
-        "_isolate_helper":
-            sdk.resolve("lib/_internal/js_runtime/lib/isolate_helper.dart"),
-        "_js_embedded_names": sdk
-            .resolve("lib/_internal/js_runtime/lib/shared/embedded_names.dart"),
-        "_js_helper":
-            sdk.resolve("lib/_internal/js_runtime/lib/js_helper.dart"),
-        "_js_mirrors":
-            sdk.resolve("lib/_internal/js_runtime/lib/js_mirrors.dart"),
-        "_js_names": sdk.resolve("lib/_internal/js_runtime/lib/js_names.dart"),
-        "_js_primitives":
-            sdk.resolve("lib/_internal/js_runtime/lib/js_primitives.dart"),
-        "_metadata": sdk.resolve("lib/html/html_common/metadata.dart"),
-        "_native_typed_data":
-            sdk.resolve("lib/_internal/js_runtime/lib/native_typed_data.dart"),
-        "_vmservice": sdk.resolve("lib/vmservice/vmservice.dart"),
-        "async": sdk.resolve("lib/async/async.dart"),
-        "collection": sdk.resolve("lib/collection/collection.dart"),
-        "convert": sdk.resolve("lib/convert/convert.dart"),
-        "core": sdk.resolve("lib/core/core.dart"),
-        "developer": sdk.resolve("lib/developer/developer.dart"),
-        "html": sdk.resolve("lib/html/dart2js/html_dart2js.dart"),
-        "html_common":
-            sdk.resolve("lib/html/html_common/html_common_dart2js.dart"),
-        "indexed_db":
-            sdk.resolve("lib/indexed_db/dart2js/indexed_db_dart2js.dart"),
-        "io": sdk.resolve("lib/io/io.dart"),
-        "isolate": sdk.resolve("lib/isolate/isolate.dart"),
-        "js": sdk.resolve("lib/js/dart2js/js_dart2js.dart"),
-        "js_util": sdk.resolve("lib/js_util/dart2js/js_util_dart2js.dart"),
-        "math": sdk.resolve("lib/math/math.dart"),
-        "mirrors": sdk.resolve("lib/mirrors/mirrors.dart"),
-        "nativewrappers": sdk.resolve("lib/html/dartium/nativewrappers.dart"),
-        "profiler": sdk.resolve("lib/profiler/profiler.dart"),
-        "svg": sdk.resolve("lib/svg/dart2js/svg_dart2js.dart"),
-        "typed_data": sdk.resolve("lib/typed_data/typed_data.dart"),
-        "vmservice_io": sdk.resolve("lib/vmservice_io/vmservice_io.dart"),
-        "web_audio":
-            sdk.resolve("lib/web_audio/dart2js/web_audio_dart2js.dart"),
-        "web_gl": sdk.resolve("lib/web_gl/dart2js/web_gl_dart2js.dart"),
-        "web_sql": sdk.resolve("lib/web_sql/dart2js/web_sql_dart2js.dart"),
-      };
-    }
-    uri ??= Uri.base.resolve(".packages");
+      {Uri packages}) async {
+    Uri librariesJson = sdk?.resolve("lib/libraries.json");
+
+    // TODO(ahe): Should be something like
+    // `Uri.base.resolve("runtime/vm/libraries.json")`.

[Siggi Cherem (dart-lang), 2017/05/22 16:21:15]

On the design doc, I was pushing for having a single file for declaring both the
library location and the patches. 

Some of the rationale: initially I thought it was nice to have a libraries.json
that is separate because so many libraries are available in more than one
platform, so technically we could share that .json file for all platforms. Then
I realized that every platform has at least a special library that is not
available in other platforms (vm-service for vm, js-helpers for dart2js, dart:ui
for flutter... ), so we end up needing a libraries.json per platform anyways. 

We can continue the discussion on that doc if you prefer.

I'm using YAML syntax here, but here is what I have in mind. If we have a single
Uri, it can look like:

libraries:
  async:
    path: uri1
    patch: uri2

If we must continue using a list of files for the VM then:

libraries:
  async:
    path: uri1
    patches:
      - uri2
      - uri3

[ahe, 2017/05/22 16:26:47]

OK. That's great, in that case, I should delete runtime/vm/libraries.json.

+    Uri patches = null;
+
+    packages ??= Uri.base.resolve(".packages");
 
     List<int> bytes;
     try {
-      bytes = await fileSystem.entityForUri(uri).readAsBytes();
+      bytes = await fileSystem.entityForUri(packages).readAsBytes();
     } on FileSystemException catch (e) {
-      inputError(uri, -1, e.message);
+      inputError(packages, -1, e.message);
     }
 
-    Map<String, Uri> packages = const <String, Uri>{};
+    Map<String, Uri> parsedPackages;
     try {
-      packages = packages_file.parse(bytes, uri);
+      parsedPackages = packages_file.parse(bytes, packages);
     } on FormatException catch (e) {
-      return inputError(uri, e.offset, e.message);
+      return inputError(packages, e.offset, e.message);
     }
-    return new TranslateUri(packages, dartLibraries);
+    return new TranslateUri(
+        parsedPackages,
+        await computeLibraries(fileSystem, librariesJson),
+        await computePatches(fileSystem, patches));
   }
 }
+
+Future<Map<String, Uri>> computeLibraries(
+    FileSystem fileSystem, Uri uri) async {
+  if (uri == null) return const <String, Uri>{};
+  Map<String, String> libraries = JSON
+      .decode(await fileSystem.entityForUri(uri).readAsString())["libraries"];
+  Map<String, Uri> result = <String, Uri>{};
+  libraries.forEach((String name, String path) {
+    result[name] = uri.resolve(path);
+  });
+  return result;
+}
+
+Future<Map<String, List<Uri>>> computePatches(
+    FileSystem fileSystem, Uri uri) async {
+  if (uri == null) return const <String, List<Uri>>{};
+  Map<String, List<Uri>> result = <String, List<Uri>>{};

[Siggi Cherem (dart-lang), 2017/05/22 16:21:15]

until we add the support for patching and decide on how to encode it, can we
remove the body of this function and throw with an unimplemented error?

[ahe, 2017/05/22 16:26:47]

Sure.

+  JSON
+      .decode(await fileSystem.entityForUri(uri).readAsString())
+      .forEach((String name, data) {
+    List<String> sources = data["sources"];
+    Uri directory = uri.resolve("${data['directory']}/");
+    List<Uri> resolvedSources = <Uri>[];
+    for (String source in sources) {
+      if (source.endsWith(".dart")) {
+        resolvedSources.add(directory.resolve(source));
+      }
+    }
+    if (resolvedSources.isNotEmpty) {
+      result[name] = resolvedSources;
+    }
+  });
+  return result;
+}