Support older SDKs in analyzer.

pkg/analyzer/lib/src/generated/sdk_io.dart

 // Copyright (c) 2014, 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 engine.sdk.io;
 
 import 'dart:io';
 
 import 'package:analyzer/src/context/context.dart' as newContext;
 import 'package:analyzer/src/generated/java_engine.dart';
@@ skipping 321 matching lines @@
    */
   JavaFile get libraryDirectory =>
       new JavaFile.relative(_sdkDirectory, _LIB_DIRECTORY_NAME);
 
   /**
    * Return the file containing the Pub executable, or `null` if it does not exist.
    */
   JavaFile get pubExecutable {
     if (_pubExecutable == null) {
       _pubExecutable = _verifyExecutable(new JavaFile.relative(
-          new JavaFile.relative(_sdkDirectory, _BIN_DIRECTORY_NAME), OSUtilities
-              .isWindows() ? _PUB_EXECUTABLE_NAME_WIN : _PUB_EXECUTABLE_NAME));
+          new JavaFile.relative(_sdkDirectory, _BIN_DIRECTORY_NAME),
+          OSUtilities.isWindows()
+              ? _PUB_EXECUTABLE_NAME_WIN
+              : _PUB_EXECUTABLE_NAME));
     }
     return _pubExecutable;
   }
 
   @override
   List<SdkLibrary> get sdkLibraries => _libraryMap.sdkLibraries;
 
   /**
    * Return the revision number of this SDK, or `"0"` if the revision number
    * cannot be discovered.
@@ skipping 36 matching lines @@
    */
   JavaFile get vmExecutable {
     if (_vmExecutable == null) {
       _vmExecutable = _verifyExecutable(new JavaFile.relative(
           new JavaFile.relative(_sdkDirectory, _BIN_DIRECTORY_NAME),
           vmBinaryName));
     }
     return _vmExecutable;
   }
 
+  /**
+   * Determine the search order for trying to locate the [_LIBRARIES_FILE].
+   */
+  Iterable<JavaFile> get _libraryMapLocations sync* {
+    yield new JavaFile.relative(
+        new JavaFile.relative(
+            new JavaFile.relative(
+                new JavaFile.relative(libraryDirectory, _INTERNAL_DIR),
+                _SDK_LIBRARY_METADATA_DIR),
+            _SDK_LIBRARY_METADATA_LIB_DIR),
+        _LIBRARIES_FILE);
+    yield new JavaFile.relative(
+        new JavaFile.relative(libraryDirectory, _INTERNAL_DIR),
+        _LIBRARIES_FILE);
+  }
+
   @override
   Source fromFileUri(Uri uri) {
     JavaFile file = new JavaFile.fromUri(uri);
     String filePath = file.getAbsolutePath();
     String libPath = libraryDirectory.getAbsolutePath();
     if (!filePath.startsWith("$libPath${JavaFile.separator}")) {
       return null;
     }
     filePath = filePath.substring(libPath.length + 1);
     for (SdkLibrary library in _libraryMap.sdkLibraries) {
@@ skipping 54 matching lines @@
 
   @override
   SdkLibrary getSdkLibrary(String dartUri) => _libraryMap.getLibrary(dartUri);
 
   /**
    * Read all of the configuration files to initialize the library maps. The
    * flag [useDart2jsPaths] is `true` if the dart2js path should be used when it
    * is available. Return the initialized library map.
    */
   LibraryMap initialLibraryMap(bool useDart2jsPaths) {
-    JavaFile librariesFile = new JavaFile.relative(
-        new JavaFile.relative(
-          new JavaFile.relative(
-            new JavaFile.relative(libraryDirectory, _INTERNAL_DIR),
-            _SDK_LIBRARY_METADATA_DIR),
-          _SDK_LIBRARY_METADATA_LIB_DIR),
-        _LIBRARIES_FILE);
-    try {
-      String contents = librariesFile.readAsStringSync();
-      return new SdkLibrariesReader(useDart2jsPaths).readFromFile(
-          librariesFile, contents);
-    } catch (exception, stackTrace) {
-      AnalysisEngine.instance.logger.logError(
-          "Could not initialize the library map from ${librariesFile.getAbsolutePath()}",
-          new CaughtException(exception, stackTrace));
-      return new LibraryMap();
+    List<String> searchedPaths = <String>[];
+    var lastStackTrace = null;
+    var lastException = null;
+    for (JavaFile librariesFile in _libraryMapLocations) {
+      try {
+        String contents = librariesFile.readAsStringSync();
+        return new SdkLibrariesReader(useDart2jsPaths)
+            .readFromFile(librariesFile, contents);
+      } catch (exception, stackTrace) {
+        searchedPaths.add(librariesFile.getAbsolutePath());
+        lastException = exception;
+        lastStackTrace = stackTrace;
+      }
     }
+    AnalysisEngine.instance.logger.logError(
+        "Could not initialize the library map from $searchedPaths",
+        new CaughtException(lastException, lastStackTrace));
+    return new LibraryMap();
   }
 
   @override
   Source mapDartUri(String dartUri) {
     String libraryName;
     String relativePath;
     int index = dartUri.indexOf('/');
     if (index >= 0) {
       libraryName = dartUri.substring(0, index);
       relativePath = dartUri.substring(index + 1);
@@ skipping 81 matching lines @@
     SdkLibrariesReader_LibraryBuilder libraryBuilder =
         new SdkLibrariesReader_LibraryBuilder(_useDart2jsPaths);
     // If any syntactic errors were found then don't try to visit the AST
     // structure.
     if (!errorListener.errorReported) {
       unit.accept(libraryBuilder);
     }
     return libraryBuilder.librariesMap;
   }
 }