Resolve SDK footer text URI in templates.dart (#2146)

* Resolve SDK footer text URI in templates.dart

Moves resolution of the SDK footer text since we need to know the
format first and we can't make an await call inside the _compute
function of a DartdocSyntheticOption.

* Fix generated resources.g.dart

Author: jdkoren

lib/resources/sdk_footer_text.md

@@ -0,0 +1 @@
+• [cc license](http://creativecommons.org/licenses/by-sa/4.0/)

lib/src/generator.dart

@@ -7,13 +7,10 @@ library dartdoc.generator;
 
 import 'dart:async' show Future;
 import 'dart:io' show Directory;
-import 'dart:isolate';
 
 import 'package:dartdoc/src/dartdoc_options.dart';
 import 'package:dartdoc/src/model/model.dart' show PackageGraph;
-import 'package:dartdoc/src/package_meta.dart';
 import 'package:dartdoc/src/warnings.dart';
-import 'package:path/path.dart' as path;
 
 abstract class FileWriter {
   /// All filenames written by this generator.
@@ -38,12 +35,10 @@ abstract class Generator {
 mixin GeneratorContext on DartdocOptionContextBase {
   List<String> get footer => optionSet['footer'].valueAt(context);
 
-  /// _footerText is only used to construct synthetic options.
-  // ignore: unused_element
-  List<String> get _footerText => optionSet['footerText'].valueAt(context);
+  List<String> get footerText => optionSet['footerText'].valueAt(context);
 
-  List<String> get footerTextPaths =>
-      optionSet['footerTextPaths'].valueAt(context);
+  // Synthetic. TODO(jcollins-g): Eliminate special case for SDK and use config file.
+  bool get addSdkFooter => optionSet['addSdkFooter'].valueAt(context);
 
   List<String> get header => optionSet['header'].valueAt(context);
 
@@ -60,19 +55,7 @@ mixin GeneratorContext on DartdocOptionContextBase {
   bool get useBaseHref => optionSet['useBaseHref'].valueAt(context);
 }
 
-Uri _sdkFooterCopyrightUri;
-
-Future<void> _setSdkFooterCopyrightUri() async {
-  if (_sdkFooterCopyrightUri == null) {
-    // TODO(jdkoren): find a way to make this not specific to HTML, or have
-    // alternatives for other supported formats.
-    _sdkFooterCopyrightUri = await Isolate.resolvePackageUri(
-        Uri.parse('package:dartdoc/resources/sdk_footer_text.html'));
-  }
-}
-
 Future<List<DartdocOption>> createGeneratorOptions() async {
-  await _setSdkFooterCopyrightUri();
   return <DartdocOption>[
     DartdocOptionArgFile<List<String>>('footer', [],
         isFile: true,
@@ -89,23 +72,12 @@ Future<List<DartdocOption>> createGeneratorOptions() async {
             'package name and version).',
         mustExist: true,
         splitCommas: true),
-    DartdocOptionSyntheticOnly<List<String>>(
-      'footerTextPaths',
-      (DartdocSyntheticOption<List<String>> option, Directory dir) {
-        final List<String> footerTextPaths = <String>[];
-        final PackageMeta topLevelPackageMeta =
-            option.root['topLevelPackageMeta'].valueAt(dir);
-        // TODO(jcollins-g): Eliminate special casing for SDK and use config file.
-        if (topLevelPackageMeta.isSdk == true) {
-          footerTextPaths
-              .add(path.canonicalize(_sdkFooterCopyrightUri.toFilePath()));
-        }
-        footerTextPaths.addAll(option.parent['footerText'].valueAt(dir));
-        return footerTextPaths;
+    DartdocOptionSyntheticOnly<bool>(
+      'addSdkFooter',
+      (DartdocSyntheticOption<bool> option, Directory dir) {
+        return option.root['topLevelPackageMeta'].valueAt(dir).isSdk;
       },
-      isFile: true,
-      help: 'paths to footer-text-files (adding special case for SDK)',
-      mustExist: true,
+      help: 'Whether the SDK footer text should be added (synthetic)',
     ),
     DartdocOptionArgFile<List<String>>('header', [],
         isFile: true,

lib/src/html/resources.g.dart

@@ -11,6 +11,7 @@ const List<String> resource_names = [
   'package:dartdoc/resources/readme.md',
   'package:dartdoc/resources/script.js',
   'package:dartdoc/resources/sdk_footer_text.html',
+  'package:dartdoc/resources/sdk_footer_text.md',
   'package:dartdoc/resources/styles.css',
   'package:dartdoc/resources/typeahead.bundle.min.js'
 ];

lib/src/html/templates.dart

@@ -6,6 +6,7 @@ library dartdoc.templates;
 
 import 'dart:async' show Future;
 import 'dart:io' show File, Directory;
+import 'dart:isolate';
 
 import 'package:dartdoc/dartdoc.dart';
 import 'package:dartdoc/src/html/resource_loader.dart' as loader;
@@ -149,18 +150,27 @@ class Templates {
   final Template topLevelPropertyTemplate;
   final Template typeDefTemplate;
 
-  static Future<Templates> fromContext(DartdocGeneratorOptionContext context) {
+  static Future<Templates> fromContext(
+      DartdocGeneratorOptionContext context) async {
     String templatesDir = context.templatesDir;
+    String format = context.format;
+    List<String> footerTextPaths = context.footerText;
+    if (context.addSdkFooter) {
+      Uri sdkFooter = await Isolate.resolvePackageUri(
+          Uri.parse('package:dartdoc/resources/sdk_footer_text.$format'));
+      footerTextPaths.add(path.canonicalize(sdkFooter.toFilePath()));
+    }
+
     if (templatesDir != null) {
-      return fromDirectory(Directory(templatesDir), context.format,
+      return fromDirectory(Directory(templatesDir), format,
           headerPaths: context.header,
           footerPaths: context.footer,
-          footerTextPaths: context.footerTextPaths);
+          footerTextPaths: footerTextPaths);
     } else {
-      return createDefault(context.format,
+      return createDefault(format,
           headerPaths: context.header,
           footerPaths: context.footer,
-          footerTextPaths: context.footerTextPaths);
+          footerTextPaths: footerTextPaths);
     }
   }