Implement deps files in compile_platform.dart.

pkg/front_end/lib/src/fasta/kernel/kernel_target.dart

 // Copyright (c) 2016, 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 fasta.kernel_target;
 
 import 'dart:async' show Future;
 
 import 'dart:io' show File, IOSink;
 
@@ skipping 50 matching lines @@
 
 import '../dill/dill_target.dart' show DillTarget;
 
 import '../errors.dart'
     show InputError, internalError, reportCrash, resetCrashReporting;
 
 import '../util/relativize.dart' show relativizeUri;
 
 import '../compiler_context.dart' show CompilerContext;
 
+import '../util/relativize.dart' show relativizeUri;
+
 import 'kernel_builder.dart'
     show
         Builder,
         ClassBuilder,
         DynamicTypeBuilder,
         InvalidTypeBuilder,
         KernelClassBuilder,
         KernelLibraryBuilder,
         KernelNamedTypeBuilder,
         KernelProcedureBuilder,
@@ skipping 173 matching lines @@
       program = link(new List<Library>.from(loader.libraries));
       if (uri == null) return program;
       return await writeLinkedProgram(uri, program, isFullProgram: false);
     } on InputError catch (e) {
       return handleInputError(uri, e, isFullProgram: false);
     } catch (e, s) {
       return reportCrash(e, s, loader?.currentUriForCrashReporting);
     }
   }
 
+  Future writeDepsFile(Uri output, Uri depsFile) async {
+    if (loader.first == null) return null;
+    StringBuffer sb = new StringBuffer();
+    Uri base = depsFile.resolve(".");
+    sb.write(Uri.parse(relativizeUri(output, base: base)).toFilePath());
+    sb.write(":");
+    for (Uri dependency in loader.getDependencies()) {
+      sb.write(" ");
+      sb.write(Uri.parse(relativizeUri(dependency, base: base)).toFilePath());
+    }
+    sb.writeln();
+    await new File.fromUri(depsFile).writeAsString("$sb");
+  }
+
   Program erroneousProgram(bool isFullProgram) {
     Uri uri = loader.first?.uri ?? Uri.parse("error:error");
     Uri fileUri = loader.first?.fileUri ?? uri;
     KernelLibraryBuilder library =
         new KernelLibraryBuilder(uri, fileUri, loader);
     loader.first = library;
     if (isFullProgram) {
       // If this is an outline, we shouldn't add an executable main
       // method. Similarly considerations apply to separate compilation. It
       // could also make sense to add a way to mark .dill files as having
@@ skipping 319 matching lines @@
   }
   for (Constructor constructor in superclass.constructors) {
     if (constructor.name.name.isEmpty) {
       return constructor.function.requiredParameterCount == 0
           ? constructor
           : null;
     }
   }
   return null;
 }