Dart: Allows the mojom package's generate script to download .mojoms.

mojo/dart/mojom/lib/src/utils.dart

Index: mojo/dart/mojom/lib/src/utils.dart
diff --git a/mojo/dart/mojom/lib/src/utils.dart b/mojo/dart/mojom/lib/src/utils.dart
new file mode 100644
index 0000000000000000000000000000000000000000..65ba2485a7a3f7e9446b07ca21cd34165b42adea
--- /dev/null
+++ b/mojo/dart/mojom/lib/src/utils.dart
@@ -0,0 +1,100 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+part of generate;
+
+bool isMojomDart(String path) => path.endsWith('.mojom.dart');
+bool isMojom(String path) => path.endsWith('.mojom');
+
+/// An Error for problems on the command line.
+class CommandLineError extends Error {
+  final _msg;
+  CommandLineError(this._msg);
+  toString() => _msg;
+}
+
+/// An Error for failures of the bindings generation script.
+class GenerationError extends Error {
+  final _msg;
+  GenerationError(this._msg);
+  toString() => _msg;
+}
+
+/// An Error for failing to download a .mojom file.
+class DownloadError extends Error {
+  final _msg;
+  DownloadError(this._msg);
+  toString() => _msg;
+}
+
+/// The base type of data passed to actions for [mojomDirIter].
+class PackageIterData {
+  final Directory _mojomPackage;
+  PackageIterData(this._mojomPackage);
+  Directory get mojomPackage => _mojomPackage;
+}
+
+/// Data for [mojomDirIter] that includes the path to the Mojo SDK for bindings
+/// generation.
+class GenerateIterData extends PackageIterData {
+  final Directory _mojoSdk;
+  GenerateIterData(this._mojoSdk, Directory mojomPackage)
+      : super(mojomPackage);
+  Directory get mojoSdk => _mojoSdk;
+}
+
+/// The type of action performed by [mojomDirIter].
+typedef Future MojomAction(PackageIterData data, Directory mojomDirectory);
+
+packageDirIter(
+    Directory packages, PackageIterData data, MojomAction action) async {
+  await for (var package in packages.list()) {
+    if (package is Directory) {
+      await action(data, package);
+    }
+  }
+}
+
+/// Iterates over mojom directories of Dart packages, taking some action for
+/// each.
+///
+/// For each 'mojom' subdirectory of each subdirectory in [packages], runs
+/// [action] on the subdirectory passing along [data] to [action].
+mojomDirIter(
+    Directory packages, PackageIterData data, MojomAction action) async {
+  await packageDirIter(packages, data, (d, p) async {
+    if (p.path == d.mojomPackage.path) return;
+    if (verbose) print("package = $p");
+    final mojomDirectory = new Directory(path.join(p.path, 'mojom'));
+    if (verbose) print("looking for = $mojomDirectory");
+    if (await mojomDirectory.exists()) {
+      await action(d, mojomDirectory);
+    } else if (verbose) {
+      print("$mojomDirectory not found");
+    }
+  });
+}
+
+/// Download file at [url] using [httpClient]. Throw a [DownloadError] if
+/// the file is not successfully downloaded.
+Future<String> getUrl(HttpClient httpClient, String url) async {
+  try {
+    var request = await httpClient.getUrl(Uri.parse(url));
+    var response = await request.close();
+    if (response.statusCode >= 400) {
+      var msg = "Failed to download $url\nCode ${response.statusCode}";
+      if (response.reasonPhrase != null) {
+        msg = "$msg: ${response.reasonPhrase}";
+      }
+      throw new DownloadError(msg);
+    }
+    var fileString = new StringBuffer();
+    await for (String contents in response.transform(UTF8.decoder)) {
+      fileString.write(contents);
+    }
+    return fileString.toString();
+  } catch(e) {
+    throw new DownloadError("$e");
+  }
+}