Add a `strong-outputs` mode to build_sdk_summaries.dart.

pkg/analyzer/tool/summary/build_sdk_summaries.dart

 import 'dart:io';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/java_io.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/sdk_io.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/summary/flat_buffers.dart' as fb;
 import 'package:analyzer/src/summary/index_unit.dart';
 import 'package:analyzer/src/summary/summarize_elements.dart';
 import 'package:path/path.dart';
 
 main(List<String> args) {
   if (args.length < 1) {
     _printUsage();
     exitCode = 1;
     return;
   }
   String command = args[0];
-  if (command == 'multiple-outputs' && args.length >= 2 && args.length <= 3) {
+  if ((command == 'multiple-outputs' || command == 'strong-outputs') &&
+      args.length >= 2 &&
+      args.length <= 3) {
+    bool includeSpec = command != 'strong-outputs';
     //
     // Prepare the output path.
     //
     String outputDirectoryPath = args[1];
     if (!FileSystemEntity.isDirectorySync(outputDirectoryPath)) {
       print("'$outputDirectoryPath' is not a directory.");
       _printUsage();
       exitCode = 1;
       return;
     }
     //
     // Prepare results.
     //
     String sdkPath = args.length > 2 ? args[2] : null;
-    _Output output = _buildMultipleOutputs(sdkPath);
+    _Output output = _buildMultipleOutputs(sdkPath, includeSpec);
     if (output == null) {
       exitCode = 1;
       return;
     }
     //
     // Write results.
     //
-    output.spec.writeMultiple(outputDirectoryPath, 'spec');
+    if (includeSpec) {
+      output.spec.writeMultiple(outputDirectoryPath, 'spec');
+    }
     output.strong.writeMultiple(outputDirectoryPath, 'strong');
   } else if (command == 'single-output' &&
       args.length >= 2 &&
       args.length <= 3) {
     String outputPath = args[1];
     String sdkPath = args.length > 2 ? args[2] : null;
     //
     // Prepare results.
     //
-    _Output output = _buildMultipleOutputs(sdkPath);
+    _Output output = _buildMultipleOutputs(sdkPath, true);
     if (output == null) {
       exitCode = 1;
       return;
     }
     //
     // Write results.
     //
     fb.Builder builder = new fb.Builder();
     fb.Offset specSumOffset = builder.writeListUint8(output.spec.sum);
     fb.Offset specIndexOffset = builder.writeListUint8(output.spec.index);
@@ skipping 33 matching lines @@
 /**
  * The name of the SDK summaries builder application.
  */
 const BINARY_NAME = "build_sdk_summaries";
 
 const int _FIELD_SPEC_INDEX = 1;
 const int _FIELD_SPEC_SUM = 0;
 const int _FIELD_STRONG_INDEX = 3;
 const int _FIELD_STRONG_SUM = 2;
 
-_Output _buildMultipleOutputs(String sdkPath) {
+_Output _buildMultipleOutputs(String sdkPath, bool includeSpec) {
   //
   // Validate the SDK path.
   //
   if (sdkPath != null) {
     if (!FileSystemEntity.isDirectorySync('$sdkPath/lib')) {
       print("'$sdkPath/lib' does not exist.");
       _printUsage();
       return null;
     }
   } else {
     sdkPath = DirectoryBasedDartSdk.defaultSdkDirectory.getAbsolutePath();
   }
   //
   // Build spec and strong outputs.
   //
-  _BuilderOutput spec = new _Builder(sdkPath, false).build();
+  _BuilderOutput spec =
+      includeSpec ? new _Builder(sdkPath, false).build() : null;
   _BuilderOutput strong = new _Builder(sdkPath, true).build();
   return new _Output(spec, strong);
 }
 
 /**
  * Open the flat buffer in [inputPath] and extract the byte array in the [field]
  * into the [outputPath] file.
  */
 void _extractSingleOutput(String inputPath, int field, String outputPath) {
   List<int> bytes = new File(inputPath).readAsBytesSync();
   fb.BufferPointer root = new fb.BufferPointer.fromBytes(bytes);
   fb.BufferPointer table = root.derefObject();
   List<int> fieldBytes = const fb.Uint8ListReader().vTableGet(table, field);
   new File(outputPath).writeAsBytesSync(fieldBytes, mode: FileMode.WRITE_ONLY);
 }
 
 /**
  * Print information about how to use the SDK summaries builder.
  */
 void _printUsage() {
 //  print('Usage: $BINARY_NAME command output_directory_path [sdk_path]');
   print('Usage: $BINARY_NAME command arguments');
   print('Where command can be one of the following:');
   print('  multiple-outputs output_directory_path [sdk_path]');
   print('    Generate separate summary and index files.');
+  print('  strong-outputs output_directory_path [sdk_path]');
+  print('    Generate separate summary and index files (strong mode only).');
   print('  single-output output_file_path [sdk_path]');
   print('    Generate a single file with summary and index.');
   print('  extract-spec-sum input_file output_file');
   print('    Extract the spec-mode summary file.');
   print('  extract-strong-sum input_file output_file');
   print('    Extract the strong-mode summary file.');
   print('  extract-spec-index input_file output_file');
   print('    Extract the spec-mode index file.');
   print('  extract-strong-index input_file output_file');
   print('    Extract the strong-mode index file.');
@@ skipping 94 matching lines @@
     }
   }
 }
 
 class _Output {
   final _BuilderOutput spec;
   final _BuilderOutput strong;
 
   _Output(this.spec, this.strong);
 }