First step for modular output in fasta.

pkg/front_end/lib/src/base/processed_options.dart

 // Copyright (c) 2017, 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.
 
 import 'dart:async';
 
-import 'package:analyzer/src/summary/idl.dart';
 import 'package:front_end/compiler_options.dart';
 import 'package:front_end/file_system.dart';
 import 'package:front_end/src/fasta/translate_uri.dart';
 import 'package:front_end/src/base/performace_logger.dart';
 import 'package:front_end/src/incremental/byte_store.dart';
+import 'package:front_end/src/simple_error.dart';
 import 'package:package_config/packages_file.dart' as package_config;
+import 'package:kernel/kernel.dart' show Program, loadProgramFromBytes;
 
 /// Wrapper around [CompilerOptions] which exposes the options in a form useful
 /// to the front end implementation.
 ///
 /// The intent is that the front end should immediately wrap any incoming
 /// [CompilerOptions] object in this class before doing further processing, and
 /// should thereafter access all options via the wrapper.  This ensures that
 /// options are interpreted in a consistent way and that data derived from
 /// options is not unnecessarily recomputed.
 class ProcessedOptions {
   /// The raw [CompilerOptions] which this class wraps.
   final CompilerOptions _raw;
 
   /// The package map derived from the options, or `null` if the package map has
   /// not been computed yet.
   Map<String, Uri> _packages;
 
   /// The object that knows how to resolve "package:" and "dart:" URIs,
   /// or `null` if it has not been computed yet.
   TranslateUri _uriTranslator;
 
-  /// The summary bundle for the SDK, or `null` if it has not been read yet.
-  PackageBundle _sdkSummary;
+  /// The SDK summary, or `null` if it has not been read yet.
+  Program _sdkSummaryProgram;
+
+  /// The summary for each uri in `options.inputSummaries`.
+  List<Program> _inputSummariesPrograms;
 
   /// The location of the SDK, or `null` if the location hasn't been determined
   /// yet.
   Uri _sdkRoot;
 
+  Uri get sdkRoot => _sdkRoot ??= _normalizeSdkRoot();
+
   /// Initializes a [ProcessedOptions] object wrapping the given [rawOptions].
   ProcessedOptions(CompilerOptions rawOptions) : this._raw = rawOptions;
 
   /// The logger to report compilation progress.
   PerformanceLog get logger {
     return _raw.logger;
   }
 
   /// The byte storage to get and put serialized data.
   ByteStore get byteStore {
     return _raw.byteStore;
   }
 
+  /// Runs various validations checks on the input options. For instance,
+  /// if an option is a path to a file, it checks that the file exists.
+  Future<bool> validateOptions() async {
+    var fs = _raw.fileSystem;
+    var root = _raw.sdkRoot;
+
+    bool _report(String msg) {
+      _raw.onError(new SimpleError(msg));
+      return false;
+    }
+
+    if (root != null && !await fs.entityForUri(root).exists()) {
+      return _report("SDK root directory not found: ${_raw.sdkRoot}");
+    }
+
+    var summary = _raw.sdkSummary;
+    if (summary != null && !await fs.entityForUri(summary).exists()) {
+      return _report("SDK summary not found: ${_raw.sdkSummary}");
+    }
+
+    // TODO(sigmund): add checks for options that are meant to be disjoint (like
+    // sdkRoot and sdkSummary).
+    return true;
+  }
+
   /// Determine whether to generate code for the SDK when compiling a
   /// whole-program.
   bool get compileSdk => _raw.compileSdk;
 
   /// Get the [FileSystem] which should be used by the front end to access
   /// files.
   ///
   /// If the client supplied roots using [CompilerOptions.multiRoots], the
   /// returned [FileSystem] will automatically perform the appropriate mapping.
   FileSystem get fileSystem {
     // TODO(paulberry): support multiRoots.
     assert(_raw.multiRoots.isEmpty);
     return _raw.fileSystem;
   }
 
   /// Whether to interpret Dart sources in strong-mode.
   bool get strongMode => _raw.strongMode;
 
-  /// Get the summary bundle for the SDK.
-  ///
-  /// This is an asynchronous getter since file system operations are required.
-  Future<PackageBundle> getSdkSummary() async {
-    if (_sdkSummary == null) {
-      Uri summaryLocation;
-      if (_raw.sdkSummary != null) {
-        // Options sdkSummary and sdkRoot are mutually exclusive.
-        assert(_raw.sdkRoot == null);
-        // No need to look for the SDK; we were told where the SDK summary is.
-        summaryLocation = _raw.sdkSummary;
-      } else {
-        // Need to look for the SDK summary inside the SDK.
-        var sdkRoot = await _getSdkRoot();
-        summaryLocation = sdkRoot.resolve(
-            'lib/_internal/' + (_raw.strongMode ? 'strong.sum' : 'spec.sum'));
-      }
-      var summaryBytes =
-          await fileSystem.entityForUri(summaryLocation).readAsBytes();
-      _sdkSummary = new PackageBundle.fromBuffer(summaryBytes);
+  /// Get an outline program that summarizes the SDK.
+  Future<Program> get sdkSummaryProgram async {
+    if (_sdkSummaryProgram == null) {
+      if (_raw.sdkSummary == null) return null;
+      _sdkSummaryProgram = await _loadProgram(_raw.sdkSummary);
     }
-    return _sdkSummary;
+    return _sdkSummaryProgram;
+  }
+
+  /// Get the summary programs for each of the underlying `inputSummaries`
+  /// provided via [CompilerOptions].
+  Future<List<Program>> get inputSummariesPrograms async {
+    if (_inputSummariesPrograms == null) {
+      var uris = _raw.inputSummaries;
+      if (uris == null || uris.isEmpty) return const <Program>[];
+      _inputSummariesPrograms = await Future.wait(uris.map(_loadProgram));
+    }
+    return _inputSummariesPrograms;
+  }
+
+  Future<Program> _loadProgram(Uri uri) async {
+    var bytes = await fileSystem.entityForUri(uri).readAsBytes();
+    return loadProgramFromBytes(bytes)..unbindCanonicalNames();
   }
 
   /// Get the [TranslateUri] which resolves "package:" and "dart:" URIs.
   ///
   /// This is an asynchronous method since file system operations may be
   /// required to locate/read the packages file as well as SDK metadata.
   Future<TranslateUri> getUriTranslator() async {
     if (_uriTranslator == null) {
       await _getPackages();
       // TODO(scheglov) Load SDK libraries from whatever format we decide.
@@ skipping 20 matching lines @@
         _packages = package_config.parse(contents, _raw.packagesFileUri);
       }
     }
     return _packages;
   }
 
   /// Get the location of the SDK.
   ///
   /// This is an asynchronous getter since file system operations may be
   /// required to locate the SDK.
-  Future<Uri> _getSdkRoot() async {
-    if (_sdkRoot == null) {
-      // If an SDK summary location was provided, the SDK itself should not be
-      // needed.
-      assert(_raw.sdkSummary == null);
-      if (_raw.sdkRoot == null) {
-        // TODO(paulberry): implement the algorithm for finding the SDK
-        // automagically.
-        throw new UnimplementedError();
-      }
-      _sdkRoot = _raw.sdkRoot;
-      if (!_sdkRoot.path.endsWith('/')) {
-        _sdkRoot = _sdkRoot.replace(path: _sdkRoot.path + '/');
-      }
+  Uri _normalizeSdkRoot() {
+    // If an SDK summary location was provided, the SDK itself should not be
+    // needed.
+    assert(_raw.sdkSummary == null);
+    if (_raw.sdkRoot == null) {
+      // TODO(paulberry): implement the algorithm for finding the SDK
+      // automagically.
+      throw new UnimplementedError();
     }
-    return _sdkRoot;
+    var root = _raw.sdkRoot;
+    if (!root.path.endsWith('/')) {
+      root = root.replace(path: _sdkRoot.path + '/');
+    }
+    return root;
   }
 }