[mojo-bindings] JS lite union and FlushForTesting

Adds a |flushForTesting()| method to generated interface proxies.

This requires use of interface control message bindings, which in turn
requires union support. So union support is added here as well.

Finally, this also required compiling the interface control message
bindings into the mojo_bindings_lite.js binary, so some minimal changes
were made to generated JS code to make it compiler-friendly.

Net code size increase of about 2kB.

Bug: 849993
Change-Id: Id44d2d0e5e85693937f5bcd5419429766d25e062
Reviewed-on: https://chromium-review.googlesource.com/c/1336065
Commit-Queue: Ken Rockot <rockot@google.com>
Reviewed-by: calamity <calamity@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608669}

content/test/data/lite_js_test.mojom

@@ -8,6 +8,11 @@ struct TestStruct {
   int32 x;
 };
 
+union TestUnion {
+  int32 x;
+  TestStruct s;
+};
+
 // An interface whose definition covers various types of message signatures in
 // order to exercise the lite JS mojom bindings.
 interface TestMessageTarget {
@@ -22,6 +27,7 @@ interface TestMessageTarget {
       => (string? message, array<int32>? numbers);
 
   Flatten(array<TestStruct> values) => (array<int32> values);
+  FlattenUnions(array<TestUnion> unions) => (array<int32> x, array<int32> s);
 
   RequestSubinterface(Subinterface& request, SubinterfaceClient client);
 };

mojo/public/js/BUILD.gn

@@ -4,6 +4,7 @@
 
 import("//third_party/closure_compiler/compile_js.gni")
 import("//tools/grit/grit_rule.gni")
+import("//ui/webui/webui_features.gni")
 
 interfaces_bindings_gen_dir = "$root_gen_dir/mojo/public/interfaces/bindings"
 
@@ -52,15 +53,27 @@ action("bindings") {
 }
 
 bindings_lite_sources = [ "bindings_lite.js" ]
-
+interface_control_messages_sources = [ "$root_gen_dir/mojo/public/interfaces/bindings/interface_control_messages.mojom-lite.js" ]
 bindings_lite_compiled_file = "$target_gen_dir/mojo_bindings_lite.js"
 
-if (closure_compile) {
-  js_binary("bindings_lite") {
+if (closure_compile && optimize_webui) {
+  js_library("control_message_bindings_lite") {
+    sources = interface_control_messages_sources
+    extra_deps = [ "//mojo/public/interfaces/bindings:bindings_js" ]
+  }
+
+  js_library("bindings_lite_sources") {
     sources = [ "compile_preamble.js" ] + bindings_lite_sources
+  }
+
+  js_binary("bindings_lite") {
     outputs = [
       bindings_lite_compiled_file,
     ]
+    deps = [
+      ":bindings_lite_sources",
+      ":control_message_bindings_lite",
+    ]
     externs_list = [
       "$externs_path/mojo_core.js",
       "$externs_path/pending.js",
@@ -73,11 +86,12 @@ if (closure_compile) {
 } else {
   action("bindings_lite") {
     script = "//v8/tools/concatenate-files.py"
-    sources = bindings_lite_sources
+    sources = bindings_lite_sources + interface_control_messages_sources
     outputs = [
       bindings_lite_compiled_file,
     ]
-    args = rebase_path(bindings_lite_sources, root_build_dir)
+    args = rebase_path(bindings_lite_sources, root_build_dir) +
+           rebase_path(interface_control_messages_sources, root_build_dir)
     args += [ rebase_path(bindings_lite_compiled_file, root_build_dir) ]
     deps = [
       "//mojo/public/interfaces/bindings:bindings_js__generator",

mojo/public/tools/bindings/BUILD.gn

@@ -72,6 +72,7 @@ action("precompile_templates") {
     "$mojom_generator_root/generators/js_templates/lite/struct_definition.tmpl",
     "$mojom_generator_root/generators/js_templates/lite/struct_externs.tmpl",
     "$mojom_generator_root/generators/js_templates/lite/union_definition.tmpl",
+    "$mojom_generator_root/generators/js_templates/lite/union_externs.tmpl",
     "$mojom_generator_root/generators/js_templates/module.amd.tmpl",
     "$mojom_generator_root/generators/js_templates/module_definition.tmpl",
     "$mojom_generator_root/generators/js_templates/struct_definition.tmpl",

mojo/public/tools/bindings/generators/js_templates/lite/interface_definition.tmpl

@@ -71,6 +71,12 @@ class {{interface.name}}Proxy {
         ]);
   }
 {%-  endfor %}
+
+
+  /** @return {!Promise} */
+  flushForTesting() {
+    return this.proxy.flushForTesting();
+  }
 }
 
 /**

mojo/public/tools/bindings/generators/js_templates/lite/module.externs.tmpl

@@ -28,3 +28,8 @@ goog.provide('{{module.namespace}}.{{constant.name}}');
 {%- for struct in structs -%}
 {%-   include "lite/struct_externs.tmpl" %}
 {%  endfor -%}
+
+{#--- Union definitions #}
+{%- for union in unions -%}
+{%-   include "lite/union_externs.tmpl" %}
+{%  endfor -%}

mojo/public/tools/bindings/generators/js_templates/lite/module_definition.tmpl

@@ -14,35 +14,39 @@ let {{ enum_def(enum.name, enum) }}
 {%   include "lite/interface_definition.tmpl" %}
 {%- endfor %}
 
-{#--- Struct definitions #}
+{#--- Struct and Union forward declarations #}
 {%  for struct in structs %}
-let {{struct.name}} = {};
-{%- endfor -%}
+const {{struct.name}} = {};
+{%- endfor %}
+{%- for union in unions %}
+const {{union.name}} = {};
+{%- endfor %}
+
+{#--- Struct definitions #}
 {%  for struct in structs %}
 {%-   include "lite/struct_definition.tmpl" %}
 {%- endfor -%}
 
 {#--- Union definitions #}
-{% from "lite/union_definition.tmpl" import union_def %}
-{%- for union in unions %}
-{{union_def(union, generate_fuzzing)|indent(2)}}
-{%- endfor %}
+{%  for union in unions %}
+{%-   include "lite/union_definition.tmpl" %}
+{% endfor %}
 
 {%- for constant in module.constants %}
-exports.{{constant.name}} = {{constant.name}};
+exports['{{constant.name}}'] = {{constant.name}};
 {%- endfor %}
 {%- for enum in enums %}
-exports.{{enum.name}} = {{enum.name}};
+exports['{{enum.name}}'] = {{enum.name}};
 {%- endfor %}
 {%- for struct in structs if struct.exported %}
-exports.{{struct.name}} = {{struct.name}};
+exports['{{struct.name}}'] = {{struct.name}};
 {%- endfor %}
 {%- for union in unions %}
-exports.{{union.name}} = {{union.name}};
+exports['{{union.name}}'] = {{union.name}};
 {%- endfor %}
 {%- for interface in interfaces %}
-exports.{{interface.name}} = {{interface.name}};
-exports.{{interface.name}}Request = {{interface.name}}Request;
-exports.{{interface.name}}Proxy = {{interface.name}}Proxy;
-exports.{{interface.name}}CallbackRouter = {{interface.name}}CallbackRouter;
+exports['{{interface.name}}'] = {{interface.name}};
+exports['{{interface.name}}Request'] = {{interface.name}}Request;
+exports['{{interface.name}}Proxy'] = {{interface.name}}Proxy;
+exports['{{interface.name}}CallbackRouter'] = {{interface.name}}CallbackRouter;
 {%- endfor %}

mojo/public/tools/bindings/generators/js_templates/lite/union_definition.tmpl

-{%- macro union_def(union, generate_fuzzing) -%}
-{%- endmacro %}
+
+mojo.mojom.Union(
+    {{union.name}}, '{{union.name}}',
+    {
+{%- for field in union.fields %}
+      '{{field.name}}': {
+        'ordinal': {{field.ordinal}},
+        'type': {{field.kind|lite_js_type}},
+{%-    if field.kind.is_nullable %}
+        'nullable': true,
+{%-    endif %}
+      },
+{%- endfor %}
+    });

mojo/public/tools/bindings/generators/js_templates/lite/union_externs.tmpl

+{# Note that goog.provide is understood by the Closure Compiler even if the
+   Closure base library is unavailable. See https://crbug.com/898692 #}
+goog.provide('{{module.namespace}}.{{union.name}}');
+
+{{module.namespace}}.{{union.name}} = class {
+  constructor() {
+{%- for field in fields %}
+    /** @type { {{field.kind|lite_closure_type_with_nullability}} } */
+    this.{{field.name}};
+{%-  endfor %}
+  }
+};

mojo/public/tools/bindings/generators/mojom_js_generator.py

@@ -417,9 +417,8 @@ class Generator(generator.Generator):
     if (mojom.IsStructKind(kind) or
         mojom.IsEnumKind(kind)):
       return kind.module.namespace + "." + kind.name
-    # TODO(calamity): Support unions properly.
     if mojom.IsUnionKind(kind):
-      return "Object"
+      return kind.module.namespace + "." + kind.name
     if mojom.IsArrayKind(kind):
       return "Array<%s>" % self._ClosureType(kind.kind)
     if mojom.IsMapKind(kind) and self._IsStringableKind(kind.key_kind):

third_party/WebKit/LayoutTests/mojo/bindings-lite.html

@@ -19,6 +19,7 @@ class TargetImpl {
   ping() { return Promise.resolve(); }
   repeat(message, numbers) { return {message: message, numbers: numbers}; }
   flatten(values) {}
+  flattenUnions(unions) {}
   requestSubinterface(request, client) {}
 }
 
@@ -121,11 +122,42 @@ promise_test(() => {
 }, 'can send and receive interface requests and proxies');
 
 promise_test(() => {
-  let targetRouter = new liteJsTest.mojom.TestMessageTargetCallbackRouter;
-  let targetProxy = targetRouter.createProxy();
+  const targetRouter = new liteJsTest.mojom.TestMessageTargetCallbackRouter;
+  const targetProxy = targetRouter.createProxy();
   targetRouter.flatten.addListener(values => ({values: values.map(v => v.x)}));
   return targetProxy.flatten([{x: 1}, {x: 2}, {x: 3}]).then(reply => {
     assert_array_equals(reply.values, [1, 2, 3]);
   });
 }, 'regression test for complex array serialization');
+
+promise_test(() => {
+  const targetRouter = new liteJsTest.mojom.TestMessageTargetCallbackRouter;
+  const targetProxy = targetRouter.createProxy();
+  targetRouter.flattenUnions.addListener(unions => {
+    return {x: unions.filter(u => u.x !== undefined).map(u => u.x),
+            s: unions.filter(u => u.s !== undefined).map(u => u.s.x)};
+  });
+
+  return targetProxy.flattenUnions(
+      [{x: 1}, {x: 2}, {s: {x: 3}}, {s: {x: 4}}, {x: 5}, {s: {x: 6}}])
+      .then(reply => {
+    assert_array_equals(reply.x, [1, 2, 5]);
+    assert_array_equals(reply.s, [3, 4, 6]);
+  });
+}, 'can serialize and deserialize unions');
+
+promise_test(() => {
+  let impl = new TargetImpl;
+  let proxy = impl.target.createProxy();
+
+  // Poke a bunch of times. These should never race with the assertion below,
+  // because the |flushForTesting| request/response is ordered against other
+  // messages on |proxy|.
+  const kNumPokes = 100;
+  for (let i = 0; i < kNumPokes; ++i)
+    proxy.poke();
+  return proxy.flushForTesting().then(() => {
+    assert_equals(impl.numPokes, kNumPokes);
+  });
+}, 'can use generated flushForTesting API for synchronization in tests');
 </script>