Stop running pub get at gclient sync time and fix build bugs

mojo/public/dart/third_party/package_config/lib/discovery.dart

+// Copyright (c) 2015, 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 package_config.discovery;
+
+import "dart:async";
+import "dart:io";
+import "dart:typed_data" show Uint8List;
+
+import "package:path/path.dart" as path;
+
+import "packages.dart";
+import "packages_file.dart" as pkgfile show parse;
+import "src/packages_impl.dart";
+import "src/packages_io_impl.dart";
+
+/// Reads a package resolution file and creates a [Packages] object from it.
+///
+/// The [packagesFile] must exist and be loadable.
+/// Currently that means the URI must have a `file`, `http` or `https` scheme,
+/// and that the file can be loaded and its contents parsed correctly.
+///
+/// If the [loader] is provided, it is used to fetch non-`file` URIs, and
+/// it can support other schemes or set up more complex HTTP requests.
+///
+/// This function can be used to load an explicitly configured package
+/// resolution file, for example one specified using a `--packages`
+/// command-line parameter.
+Future<Packages> loadPackagesFile(Uri packagesFile,
+                                  {Future<List<int>> loader(Uri uri)}) {
+  Packages parseBytes(List<int> bytes) {
+    Map<String, Uri> packageMap = pkgfile.parse(bytes, packagesFile);
+    return new MapPackages(packageMap);
+  }
+  if (packagesFile.scheme == "file") {
+    File file = new File.fromUri(packagesFile);
+    return file.readAsBytes().then(parseBytes);
+  }
+  if (loader == null) {
+    return _httpGet(packagesFile).then(parseBytes);
+  }
+  return loader(packagesFile).then(parseBytes);
+}
+
+
+/// Create a [Packages] object for a package directory.
+///
+/// The [packagesDir] URI should refer to a directory.
+/// Package names are resolved as relative to sub-directories of the
+/// package directory.
+///
+/// This function can be used for explicitly configured package directories,
+/// for example one specified using a `--package-root` comand-line parameter.
+Packages getPackagesDirectory(Uri packagesDir) {
+  if (packagesDir.scheme == "file") {
+    Directory directory = new Directory.fromUri(packagesDir);
+    return new FilePackagesDirectoryPackages(directory);
+  }
+  if (!packagesDir.path.endsWith('/')) {
+    packagesDir = packagesDir.replace(path: packagesDir.path + '/');
+  }
+  return new NonFilePackagesDirectoryPackages(packagesDir);
+}
+
+
+/// Discover the package configuration for a Dart script.
+///
+/// The [baseUri] points to either the Dart script or its directory.
+/// A package resolution strategy is found by going through the following steps,
+/// and stopping when something is found.
+///
+/// * Check if a `.packages` file exists in the same directory.
+/// * If `baseUri`'s scheme is not `file`, then assume a `packages` directory
+///   in the same directory, and resolve packages relative to that.
+/// * If `baseUri`'s scheme *is* `file`:
+///   * Check if a `packages` directory exists.
+///   * Otherwise check each successive parent directory of `baseUri` for a
+///     `.packages` file.
+///
+/// If any of these tests succeed, a `Packages` class is returned.
+/// Returns the constant [noPackages] if no resolution strategy is found.
+///
+/// This function currently only supports `file`, `http` and `https` URIs.
+/// It needs to be able to load a `.packages` file from the URI, so only
+/// recognized schemes are accepted.
+///
+/// To support other schemes, or more complex HTTP requests,
+/// an optional [loader] function can be supplied.
+/// It's called to load the `.packages` file for a non-`file` scheme.
+/// The loader function returns the *contents* of the file
+/// identified by the URI it's given.
+/// The content should be a UTF-8 encoded `.packages` file, and must return an
+/// error future if loading fails for any reason.
+Future<Packages> findPackages(Uri baseUri,
+                              {Future<List<int>> loader(Uri unsupportedUri)}) {
+  if (baseUri.scheme == "file") {
+    return new Future<Packages>.sync(() => findPackagesFromFile(baseUri));
+  } else if (loader != null) {
+    return findPackagesFromNonFile(baseUri, loader: loader);
+  } else if (baseUri.scheme == "http" || baseUri.scheme == "https") {
+    return findPackagesFromNonFile(baseUri, loader: _httpGet);
+  } else {
+    return new Future<Packages>.value(Packages.noPackages);
+  }
+}
+
+/// Find the location of the package resolution file/directory for a Dart file.
+///
+/// Checks for a `.packages` file in the [workingDirectory].
+/// If not found, checks for a `packages` directory in the same directory.
+/// If still not found, starts checking parent directories for
+/// `.packages` until reaching the root directory.
+///
+/// Returns a [File] object of a `.packages` file if one is found, or a
+/// [Directory] object for the `packages/` directory if that is found.
+FileSystemEntity _findPackagesFile(String workingDirectory) {
+  var dir = new Directory(workingDirectory);
+  if (!dir.isAbsolute) dir = dir.absolute;
+  if (!dir.existsSync()) {
+    throw new ArgumentError.value(
+        workingDirectory, "workingDirectory", "Directory does not exist.");
+  }
+  File checkForConfigFile(Directory directory) {
+    assert(directory.isAbsolute);
+    var file = new File(path.join(directory.path, ".packages"));
+    if (file.existsSync()) return file;
+    return null;
+  }
+  // Check for $cwd/.packages
+  var packagesCfgFile = checkForConfigFile(dir);
+  if (packagesCfgFile != null) return packagesCfgFile;
+  // Check for $cwd/packages/
+  var packagesDir = new Directory(path.join(dir.path, "packages"));
+  if (packagesDir.existsSync()) return packagesDir;
+  // Check for cwd(/..)+/.packages
+  var parentDir = dir.parent;
+  while (parentDir.path != dir.path) {
+    packagesCfgFile = checkForConfigFile(parentDir);
+    if (packagesCfgFile != null) break;
+    dir = parentDir;
+    parentDir = dir.parent;
+  }
+  return packagesCfgFile;
+}
+
+/// Finds a package resolution strategy for a local Dart script.
+///
+/// The [fileBaseUri] points to either a Dart script or the directory of the
+/// script. The `fileBaseUri` must be a `file:` URI.
+///
+/// This function first tries to locate a `.packages` file in the `fileBaseUri`
+/// directory. If that is not found, it instead checks for the presence of
+/// a `packages/` directory in the same place.
+/// If that also fails, it starts checking parent directories for a `.packages`
+/// file, and stops if it finds it.
+/// Otherwise it gives up and returns [Packages.noPackages].
+Packages findPackagesFromFile(Uri fileBaseUri) {
+  Uri baseDirectoryUri = fileBaseUri;
+  if (!fileBaseUri.path.endsWith('/')) {
+    baseDirectoryUri = baseDirectoryUri.resolve(".");
+  }
+  String baseDirectoryPath = baseDirectoryUri.toFilePath();
+  FileSystemEntity location = _findPackagesFile(baseDirectoryPath);
+  if (location == null) return Packages.noPackages;
+  if (location is File) {
+    List<int> fileBytes = location.readAsBytesSync();
+    Map<String, Uri> map =
+        pkgfile.parse(fileBytes, new Uri.file(location.path));
+    return new MapPackages(map);
+  }
+  assert(location is Directory);
+  return new FilePackagesDirectoryPackages(location);
+}
+
+/// Finds a package resolution strategy for a Dart script.
+///
+/// The [nonFileUri] points to either a Dart script or the directory of the
+/// script.
+/// The [nonFileUri] should not be a `file:` URI since the algorithm for
+/// finding a package resolution strategy is more elaborate for `file:` URIs.
+/// In that case, use [findPackagesFromFile].
+///
+/// This function first tries to locate a `.packages` file in the [nonFileUri]
+/// directory. If that is not found, it instead assumes a `packages/` directory
+/// in the same place.
+///
+/// By default, this function only works for `http:` and `https:` URIs.
+/// To support other schemes, a loader must be provided, which is used to
+/// try to load the `.packages` file. The loader should return the contents
+/// of the requested `.packages` file as bytes, which will be assumed to be
+/// UTF-8 encoded.
+Future<Packages> findPackagesFromNonFile(Uri nonFileUri,
+                                         {Future<List<int>> loader(Uri name)}) {
+  if (loader == null) loader = _httpGet;
+  Uri packagesFileUri = nonFileUri.resolve(".packages");
+  return loader(packagesFileUri).then((List<int> fileBytes) {
+    Map<String, Uri> map = pkgfile.parse(fileBytes, packagesFileUri);
+    return new MapPackages(map);
+  }, onError: (_) {
+    // Didn't manage to load ".packages". Assume a "packages/" directory.
+    Uri packagesDirectoryUri = nonFileUri.resolve("packages/");
+    return new NonFilePackagesDirectoryPackages(packagesDirectoryUri);
+  });
+}
+
+/// Fetches a file over http.
+Future<List<int>> _httpGet(Uri uri) async {
+  HttpClient client = new HttpClient();
+  HttpClientRequest request = await client.getUrl(uri);
+  HttpClientResponse response = await request.close();
+  if (response.statusCode != HttpStatus.OK) {
+    throw 'Failure getting $uri: '
+        '${response.statusCode} ${response.reasonPhrase}';
+  }
+  List<List<int>> splitContent = await response.toList();
+  int totalLength = 0;
+  for (var list in splitContent) {
+    totalLength += list.length;
+  }
+  Uint8List result = new Uint8List(totalLength);
+  int offset = 0;
+  for (List<int> contentPart in splitContent) {
+    result.setRange(offset, offset + contentPart.length, contentPart);
+    offset += contentPart.length;
+  }
+  return result;
+}