Support custom partial resolvers in Mustachio

lib/src/generator/templates.renderers.dart

@@ -16,10 +16,12 @@ String _simpleResolveErrorMessage(List<String> key, String type) =>
     'expose the properties of $type by adding it to the @Renderer '
     "annotation's 'visibleTypes' list";
 
-String renderIndex(PackageTemplateData context, File file) {
+String renderIndex(PackageTemplateData context, File file,
+    {PartialResolver partialResolver}) {
   try {
     var parser = MustachioParser(file.readAsStringSync());
-    return _render_PackageTemplateData(context, parser.parse(), file);
+    return _render_PackageTemplateData(context, parser.parse(), file,
+        partialResolver: partialResolver);
   } on FileSystemException catch (e) {
     throw MustachioResolutionError(
         'FileSystemException when reading template "${file.path}": ${e.message}');
@@ -28,8 +30,9 @@ String renderIndex(PackageTemplateData context, File file) {
 
 String _render_PackageTemplateData(
     PackageTemplateData context, List<MustachioNode> ast, File file,
-    {RendererBase<Object> parent}) {
-  var renderer = _Renderer_PackageTemplateData(context, parent, file);
+    {RendererBase<Object> parent, PartialResolver partialResolver}) {
+  var renderer = _Renderer_PackageTemplateData(context, parent, file,
+      partialResolver: partialResolver);
   renderer.renderBlock(ast);
   return renderer.buffer.toString();
 }
@@ -201,8 +204,9 @@ class _Renderer_PackageTemplateData extends RendererBase<PackageTemplateData> {
       };
 
   _Renderer_PackageTemplateData(
-      PackageTemplateData context, RendererBase<Object> parent, File file)
-      : super(context, parent, file);
+      PackageTemplateData context, RendererBase<Object> parent, File file,
+      {PartialResolver partialResolver})
+      : super(context, parent, file, partialResolver: partialResolver);
 
   @override
   Property<PackageTemplateData> getProperty(String key) {
@@ -215,8 +219,9 @@ class _Renderer_PackageTemplateData extends RendererBase<PackageTemplateData> {
 }
 
 String _render_Object(Object context, List<MustachioNode> ast, File file,
-    {RendererBase<Object> parent}) {
-  var renderer = _Renderer_Object(context, parent, file);
+    {RendererBase<Object> parent, PartialResolver partialResolver}) {
+  var renderer =
+      _Renderer_Object(context, parent, file, partialResolver: partialResolver);
   renderer.renderBlock(ast);
   return renderer.buffer.toString();
 }
@@ -241,8 +246,9 @@ class _Renderer_Object extends RendererBase<Object> {
         ),
       };
 
-  _Renderer_Object(Object context, RendererBase<Object> parent, File file)
-      : super(context, parent, file);
+  _Renderer_Object(Object context, RendererBase<Object> parent, File file,
+      {PartialResolver partialResolver})
+      : super(context, parent, file, partialResolver: partialResolver);
 
   @override
   Property<Object> getProperty(String key) {
@@ -256,8 +262,9 @@ class _Renderer_Object extends RendererBase<Object> {
 
 String _render_TemplateData<T extends Documentable>(
     TemplateData<T> context, List<MustachioNode> ast, File file,
-    {RendererBase<Object> parent}) {
-  var renderer = _Renderer_TemplateData(context, parent, file);
+    {RendererBase<Object> parent, PartialResolver partialResolver}) {
+  var renderer = _Renderer_TemplateData(context, parent, file,
+      partialResolver: partialResolver);
   renderer.renderBlock(ast);
   return renderer.buffer.toString();
 }
@@ -563,8 +570,9 @@ class _Renderer_TemplateData<T extends Documentable>
       };
 
   _Renderer_TemplateData(
-      TemplateData<T> context, RendererBase<Object> parent, File file)
-      : super(context, parent, file);
+      TemplateData<T> context, RendererBase<Object> parent, File file,
+      {PartialResolver partialResolver})
+      : super(context, parent, file, partialResolver: partialResolver);
 
   @override
   Property<TemplateData<T>> getProperty(String key) {

lib/src/mustachio/renderer_base.dart

@@ -4,8 +4,16 @@
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:meta/meta.dart';
+import 'package:path/path.dart' as path;
 import 'parser.dart';
 
+/// The signature of a partial resolver function.
+typedef PartialResolver = String Function(String path);
+
+/// The signature of a generated render function.
+typedef Renderer<T> = String Function(T context, File file,
+    {PartialResolver partialResolver});
+
 /// The base class for a generated Mustache renderer.
 abstract class RendererBase<T> {
   /// The context object which this renderer can render.
@@ -16,10 +24,23 @@ abstract class RendererBase<T> {
 
   final File template;
 
+  final PartialResolver partialResolver;
+
   /// The output buffer into which [context] is rendered, using a template.
   final buffer = StringBuffer();
 
-  RendererBase(this.context, this.parent, this.template);
+  RendererBase(this.context, this.parent, this.template,
+      {this.partialResolver});
+
+  path.Context get pathContext => template.provider.pathContext;
+
+  String _defaultResolver(String path) {
+    var partialPath = pathContext.isAbsolute(path)
+        ? path
+        : pathContext.join(template.parent.path, path);
+    var file = template.provider.getFile(pathContext.normalize(partialPath));
+    return file.readAsStringSync();
+  }
 
   void write(String text) => buffer.write(text);
 
@@ -122,18 +143,15 @@ abstract class RendererBase<T> {
 
   void partial(Partial node) {
     var key = node.key;
-    var partialPath = template.provider.pathContext.isAbsolute(key)
-        ? key
-        : template.provider.pathContext.join(template.parent.path, key);
     try {
-      var file = template.provider
-          .getFile(template.provider.pathContext.normalize(partialPath));
-      var parser = MustachioParser(file.readAsStringSync());
+      var partial = (partialResolver ?? _defaultResolver)(key);
+      var parser = MustachioParser(partial);
       var ast = parser.parse();
       renderBlock(ast);
     } on FileSystemException catch (e) {
       throw MustachioResolutionError(
-          'FileSystemException when reading partial "$key" found in template "${template.path}": ${e.message}');
+          'FileSystemException when reading partial "$key" found in template '
+          '"${template.path}": ${e.message}');
     }
   }
 }

test/mustachio/builder_test.dart

@@ -241,7 +241,8 @@ import 'package:mustachio/annotations.dart';
 
     test('with a corresponding public API function', () async {
       expect(generatedContent,
-          contains('String renderFoo<T>(Foo<T> context, File file)'));
+          contains('String renderFoo<T>(Foo<T> context, File file,'));
+      expect(generatedContent, contains('{PartialResolver partialResolver})'));
     });
 
     test('with a corresponding render function', () async {

test/mustachio/foo.renderers.dart

@@ -16,19 +16,21 @@ String _simpleResolveErrorMessage(List<String> key, String type) =>
     'expose the properties of $type by adding it to the @Renderer '
     "annotation's 'visibleTypes' list";
 
-String renderFoo(Foo context, File file) {
+String renderFoo(Foo context, File file, {PartialResolver partialResolver}) {
   try {
     var parser = MustachioParser(file.readAsStringSync());
-    return _render_Foo(context, parser.parse(), file);
+    return _render_Foo(context, parser.parse(), file,
+        partialResolver: partialResolver);
   } on FileSystemException catch (e) {
     throw MustachioResolutionError(
         'FileSystemException when reading template "${file.path}": ${e.message}');
   }
 }
 
 String _render_Foo(Foo context, List<MustachioNode> ast, File file,
-    {RendererBase<Object> parent}) {
-  var renderer = Renderer_Foo(context, parent, file);
+    {RendererBase<Object> parent, PartialResolver partialResolver}) {
+  var renderer =
+      Renderer_Foo(context, parent, file, partialResolver: partialResolver);
   renderer.renderBlock(ast);
   return renderer.buffer.toString();
 }
@@ -107,8 +109,9 @@ class Renderer_Foo extends RendererBase<Foo> {
         ...Renderer_Object.propertyMap<CT_>(),
       };
 
-  Renderer_Foo(Foo context, RendererBase<Object> parent, File file)
-      : super(context, parent, file);
+  Renderer_Foo(Foo context, RendererBase<Object> parent, File file,
+      {PartialResolver partialResolver})
+      : super(context, parent, file, partialResolver: partialResolver);
 
   @override
   Property<Foo> getProperty(String key) {
@@ -121,8 +124,9 @@ class Renderer_Foo extends RendererBase<Foo> {
 }
 
 String _render_Object(Object context, List<MustachioNode> ast, File file,
-    {RendererBase<Object> parent}) {
-  var renderer = Renderer_Object(context, parent, file);
+    {RendererBase<Object> parent, PartialResolver partialResolver}) {
+  var renderer =
+      Renderer_Object(context, parent, file, partialResolver: partialResolver);
   renderer.renderBlock(ast);
   return renderer.buffer.toString();
 }
@@ -147,8 +151,9 @@ class Renderer_Object extends RendererBase<Object> {
         ),
       };
 
-  Renderer_Object(Object context, RendererBase<Object> parent, File file)
-      : super(context, parent, file);
+  Renderer_Object(Object context, RendererBase<Object> parent, File file,
+      {PartialResolver partialResolver})
+      : super(context, parent, file, partialResolver: partialResolver);
 
   @override
   Property<Object> getProperty(String key) {
@@ -160,19 +165,21 @@ class Renderer_Object extends RendererBase<Object> {
   }
 }
 
-String renderBar(Bar context, File file) {
+String renderBar(Bar context, File file, {PartialResolver partialResolver}) {
   try {
     var parser = MustachioParser(file.readAsStringSync());
-    return _render_Bar(context, parser.parse(), file);
+    return _render_Bar(context, parser.parse(), file,
+        partialResolver: partialResolver);
   } on FileSystemException catch (e) {
     throw MustachioResolutionError(
         'FileSystemException when reading template "${file.path}": ${e.message}');
   }
 }
 
 String _render_Bar(Bar context, List<MustachioNode> ast, File file,
-    {RendererBase<Object> parent}) {
-  var renderer = Renderer_Bar(context, parent, file);
+    {RendererBase<Object> parent, PartialResolver partialResolver}) {
+  var renderer =
+      Renderer_Bar(context, parent, file, partialResolver: partialResolver);
   renderer.renderBlock(ast);
   return renderer.buffer.toString();
 }
@@ -249,8 +256,9 @@ class Renderer_Bar extends RendererBase<Bar> {
         ...Renderer_Object.propertyMap<CT_>(),
       };
 
-  Renderer_Bar(Bar context, RendererBase<Object> parent, File file)
-      : super(context, parent, file);
+  Renderer_Bar(Bar context, RendererBase<Object> parent, File file,
+      {PartialResolver partialResolver})
+      : super(context, parent, file, partialResolver: partialResolver);
 
   @override
   Property<Bar> getProperty(String key) {
@@ -262,19 +270,21 @@ class Renderer_Bar extends RendererBase<Bar> {
   }
 }
 
-String renderBaz(Baz context, File file) {
+String renderBaz(Baz context, File file, {PartialResolver partialResolver}) {
   try {
     var parser = MustachioParser(file.readAsStringSync());
-    return _render_Baz(context, parser.parse(), file);
+    return _render_Baz(context, parser.parse(), file,
+        partialResolver: partialResolver);
   } on FileSystemException catch (e) {
     throw MustachioResolutionError(
         'FileSystemException when reading template "${file.path}": ${e.message}');
   }
 }
 
 String _render_Baz(Baz context, List<MustachioNode> ast, File file,
-    {RendererBase<Object> parent}) {
-  var renderer = Renderer_Baz(context, parent, file);
+    {RendererBase<Object> parent, PartialResolver partialResolver}) {
+  var renderer =
+      Renderer_Baz(context, parent, file, partialResolver: partialResolver);
   renderer.renderBlock(ast);
   return renderer.buffer.toString();
 }
@@ -303,8 +313,9 @@ class Renderer_Baz extends RendererBase<Baz> {
         ...Renderer_Object.propertyMap<CT_>(),
       };
 
-  Renderer_Baz(Baz context, RendererBase<Object> parent, File file)
-      : super(context, parent, file);
+  Renderer_Baz(Baz context, RendererBase<Object> parent, File file,
+      {PartialResolver partialResolver})
+      : super(context, parent, file, partialResolver: partialResolver);
 
   @override
   Property<Baz> getProperty(String key) {

test/mustachio/renderer_test.dart

@@ -323,6 +323,24 @@ void main() {
             'Line 2 Partial Section Instance of \'Bar\''));
   });
 
+  test('Renderer renders a partial using a custom partial renderer', () {
+    var barTemplate = getFile('/project/bar.mustache')
+      ..writeAsStringSync('Text {{#foo}}{{>_foo.mustache}}{{/foo}}');
+    getFile('/project/_foo.mustache').writeAsStringSync('Partial {{s1}}');
+    var bar = Bar()..foo = (Foo()..s1 = 'hello');
+    String partialResolver(String path) {
+      var partialPath = resourceProvider.pathContext.isAbsolute(path)
+          ? path
+          : resourceProvider.pathContext.join('/project', path);
+      var file = resourceProvider
+          .getFile(resourceProvider.pathContext.normalize('_$partialPath'));
+      return file.readAsStringSync();
+    }
+
+    expect(renderBar(bar, barTemplate, partialResolver: partialResolver),
+        equals('Text Partial hello'));
+  });
+
   test('Renderer throws when it cannot resolve a variable key', () {
     var fooTemplate = getFile('/project/foo.mustache')
       ..writeAsStringSync('Text {{s2}}');

tool/mustachio/codegen_runtime_renderer.dart

@@ -215,10 +215,11 @@ String _simpleResolveErrorMessage(List<String> key, String type) =>
     if (renderer.publicApiFunctionName != null) {
       _buffer.writeln('''
 String ${renderer.publicApiFunctionName}${renderer._typeParametersString}(
-    $typeWithVariables context, File file) {
+    $typeWithVariables context, File file, {PartialResolver partialResolver}) {
   try {
     var parser = MustachioParser(file.readAsStringSync());
-    return ${renderer._renderFunctionName}(context, parser.parse(), file);
+    return ${renderer._renderFunctionName}(
+        context, parser.parse(), file, partialResolver: partialResolver);
   } on FileSystemException catch (e) {
     throw MustachioResolutionError(
         'FileSystemException when reading template "\${file.path}": \${e.message}');
@@ -231,8 +232,9 @@ String ${renderer.publicApiFunctionName}${renderer._typeParametersString}(
     _buffer.writeln('''
 String ${renderer._renderFunctionName}${renderer._typeParametersString}(
     $typeWithVariables context, List<MustachioNode> ast, File file,
-    {RendererBase<Object> parent}) {
-  var renderer = ${renderer._rendererClassName}(context, parent, file);
+    {RendererBase<Object> parent, PartialResolver partialResolver}) {
+  var renderer = ${renderer._rendererClassName}(
+      context, parent, file, partialResolver: partialResolver);
   renderer.renderBlock(ast);
   return renderer.buffer.toString();
 }
@@ -247,8 +249,9 @@ class ${renderer._rendererClassName}${renderer._typeParametersString}
     // Write out the constructor.
     _buffer.writeln('''
   ${renderer._rendererClassName}(
-        $typeWithVariables context, RendererBase<Object> parent, File file)
-      : super(context, parent, file);
+        $typeWithVariables context, RendererBase<Object> parent, File file,
+        {PartialResolver partialResolver})
+      : super(context, parent, file, partialResolver: partialResolver);
 ''');
     var propertyMapTypeArguments = renderer._typeArgumentsStringWith(typeName);
     var propertyMapName = 'propertyMap$propertyMapTypeArguments';