Create Whisker equivalents for remaining cpp_mstch_struct properties

Summary:
Migrate `struct:explicitly_constructed_fields` to a Whisker property on the `t_structured` prototye.

Also add `fields_in_layout_order` to the `t_structured` Whisker prototype, with the mstch property retained due to templates using mstch implicit `first?` / `last?`.

Reviewed By: iahs

Differential Revision: D96202278

fbshipit-source-id: 943ab386350b29b07cb2330125a0c436392bd0a3

Author: hchokshi

third-party/thrift/src/thrift/compiler/generate/t_mstch_cpp2_generator.cc

@@ -388,6 +388,42 @@ struct cpp2_field_generator_context {
 std::vector<const t_field*> get_structured_fields_in_layout_order(
     const t_structured& strct);
 
+/**
+ * Check fields for the meeting any of the following criteria:
+ * All enums
+ * All primitives except empty strings
+ * All non-empty structs and containers
+ * All non-optional references with basetypes, enums, non-empty structs, and
+ * containers
+ */
+bool is_field_explicitly_constructed(
+    const t_field& field, const t_structured& parent_struct) {
+  const t_type* type = field.type()->get_true_type();
+  if (cpp2::is_explicit_ref(&field) &&
+      field.qualifier() == t_field_qualifier::optional) {
+    return false;
+  }
+  if (type->is<t_enum>()) {
+    return true;
+  }
+  if (type->is<t_primitive_type>()) {
+    return !type->is_string_or_binary() || field.default_value() != nullptr ||
+        cpp2::is_explicit_ref(&field);
+  }
+  if (type->is<t_struct>() || type->is<t_union>()) {
+    return type != &parent_struct &&
+        (cpp2::is_explicit_ref(&field) ||
+         (field.default_value() != nullptr &&
+          !field.default_value()->is_empty()));
+  }
+  if (type->is<t_container>()) {
+    return cpp2::is_explicit_ref(&field) ||
+        (field.default_value() != nullptr &&
+         !field.default_value()->is_empty());
+  }
+  return false;
+}
+
 class cpp2_generator_context {
  public:
   explicit cpp2_generator_context(
@@ -1315,6 +1351,21 @@ class t_mstch_cpp2_generator : public t_mstch_generator {
           }
           return whisker::make::array(std::move(fields));
         });
+    def.property("fields_in_layout_order", [&](const t_structured& strct) {
+      return to_array(
+          cpp_context_->fields_in_layout_order(strct), proto.of<t_field>());
+    });
+    def.property(
+        "explicitly_constructed_fields", [&](const t_structured& strct) {
+          std::vector<const t_field*> filtered;
+          for (const t_field* field :
+               cpp_context_->fields_in_layout_order(strct)) {
+            if (is_field_explicitly_constructed(*field, strct)) {
+              filtered.emplace_back(field);
+            }
+          }
+          return to_array(filtered, proto.of<t_field>());
+        });
 
     return std::move(def).make();
   }
@@ -2102,8 +2153,6 @@ class cpp_mstch_struct : public mstch_struct {
     register_methods(
         this,
         {
-            {"struct:explicitly_constructed_fields",
-             &cpp_mstch_struct::explicitly_constructed_fields},
             {"struct:fields_in_layout_order",
              &cpp_mstch_struct::fields_in_layout_order},
         });
@@ -2112,42 +2161,10 @@ class cpp_mstch_struct : public mstch_struct {
  private:
   const cpp2_generator_context& cpp_context_;
 
-  mstch::node explicitly_constructed_fields() {
-    // Filter fields according to the following criteria:
-    // Get all enums
-    // Get all base_types but empty strings
-    // Get all non-empty structs and containers
-    // Get all non-optional references with basetypes, enums,
-    // non-empty structs, and containers
-    std::vector<const t_field*> filtered_fields;
-    for (const auto* field : cpp_context_.fields_in_layout_order(*struct_)) {
-      const t_type* type = field->type()->get_true_type();
-      // Filter out all optional references.
-      if (cpp2::is_explicit_ref(field) &&
-          field->qualifier() == t_field_qualifier::optional) {
-        continue;
-      }
-      if (type->is<t_enum>() ||
-          (type->is<t_primitive_type>() && !type->is_string_or_binary()) ||
-          (type->is_string_or_binary() && field->default_value() != nullptr) ||
-          (type->is<t_container>() && field->default_value() != nullptr &&
-           !field->default_value()->is_empty()) ||
-          ((type->is<t_struct>() || type->is<t_union>()) &&
-           (struct_ != type->try_as<t_struct>()) &&
-           ((field->default_value() && !field->default_value()->is_empty()) ||
-            (cpp2::is_explicit_ref(field) &&
-             field->qualifier() != t_field_qualifier::optional))) ||
-          (type->is<t_container>() && cpp2::is_explicit_ref(field) &&
-           field->qualifier() != t_field_qualifier::optional) ||
-          (type->is<t_primitive_type>() && cpp2::is_explicit_ref(field) &&
-           field->qualifier() != t_field_qualifier::optional)) {
-        filtered_fields.push_back(field);
-      }
-    }
-    return make_mstch_fields(filtered_fields);
-  }
-
   mstch::node fields_in_layout_order() {
+    // TODO(T256504524): An equivalent Whisker property has been created, but we
+    // first need to migrate templates that rely on mstch behavior like implicit
+    // `first?`/`last?` properties
     return make_mstch_fields(cpp_context_.fields_in_layout_order(*struct_));
   }
 };

third-party/thrift/src/thrift/compiler/generate/templates/cpp2/common/fields.mustache

@@ -0,0 +1,27 @@
+{{!
+
+  Copyright (c) Meta Platforms, Inc. and affiliates.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+}}
+
+{{! Note: All adapted fields need to use field tag. }}
+{{#let export partial tag |field struct|}}
+{{#pragma ignore-newlines}}
+  {{#if field.cpp_adapter}}
+::apache::thrift::op::get_field_tag<{{struct.cpp_underlying_name}}, ::apache::thrift::field_id<{{field.id}}>>
+  {{#else}}
+{{field.type_tag}}
+  {{/if field.cpp_adapter}}
+{{/let partial}}

third-party/thrift/src/thrift/compiler/generate/templates/cpp2/field/tag.mustache

@@ -13,7 +13,6 @@
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
-
-  // Note: All adapted fields need to use field tag.
-}}{{^field:cpp_adapter}}{{field:type_tag}}{{/field:cpp_adapter}}{{!
-}}{{#field:cpp_adapter}}::apache::thrift::op::get_field_tag<{{struct:cpp_underlying_name}}, ::apache::thrift::field_id<{{field:id}}>>{{/field:cpp_adapter}}
+}}
+{{#pragma ignore-newlines}}
+{{#partial fields.tag field=field:self struct=struct:self}}

third-party/thrift/src/thrift/compiler/generate/templates/cpp2/module_types.cpp.mustache

@@ -16,6 +16,7 @@
 
 }}
 {{#import "common/const_value" as const_value}}
+{{#import "common/fields" as fields}}
 {{> Autogen}}
 #include "{{program:include_prefix}}{{program:name}}_types.tcc"
 #include "{{program:include_prefix}}{{program:name}}_constants.h"

third-party/thrift/src/thrift/compiler/generate/templates/cpp2/module_types.h.mustache

@@ -16,6 +16,7 @@
 
 }}
 {{#import "common/const_value" as const_value}}
+{{#import "common/fields" as fields}}
 {{#import "types/schema_association" as schema_association}}
 {{> Autogen}}
 

third-party/thrift/src/thrift/compiler/generate/templates/cpp2/module_types_custom_protocol.h.mustache

@@ -16,6 +16,7 @@
 
 }}
 {{#import "common/const_value" as const_value}}
+{{#import "common/fields" as fields}}
 {{> Autogen}}
 #pragma once
 

third-party/thrift/src/thrift/compiler/generate/templates/cpp2/module_types_h/base_ctor_no_alloc_init_list.mustache

@@ -14,20 +14,16 @@
   See the License for the specific language governing permissions and
   limitations under the License.
 
-
-}}{{! --------------- Empty constractor, no allocator, init list
-}}{{struct:cpp_underlying_name}}(){{!
-  }}{{#struct:explicitly_constructed_fields}}{{> common/colon_newline}}{{!
-    }}{{#field:type}}{{!
-      }}    {{field:cpp_storage_name}}({{!
-      }}{{#field:cpp_ref_not_boxed?}}{{> module_types_h/smart_ptr_constructor}}{{/field:cpp_ref_not_boxed?}}{{!
-      }}{{#field:boxed_ref?}}{{> field/default}}{{/field:boxed_ref?}}{{!
-        TODO(dokwon): Support custom default for intern boxed field.
-      }}{{#field:intern_boxed_ref?}}{{field:cpp_storage_type}}::fromStaticConstant(&::apache::thrift::op::getDefault<{{> field/tag}}>()){{/field:intern_boxed_ref?}}{{!
-      }}{{^field:cpp_ref?}}{{#field:default_value}}{{!
-          Use value initialization when no custom default is provided.
-        }}{{> field/default}}{{/field:default_value}}{{!
-      }}{{/field:cpp_ref?}}{{!
-      }}){{> common/comma_newline}}{{!
-    }}{{/field:type}}{{!
-  }}{{/struct:explicitly_constructed_fields}}{{!}}
+}}{{! Empty constructor, no allocator, init list !}}
+{{#pragma ignore-newlines}}
+{{struct:cpp_underlying_name}}()
+{{#each (array.enumerate struct:explicitly_constructed_fields with_first=true with_last=true) as |i field first? last?|}}
+{{> common/colon_newline}}    {{field.cpp_storage_name}}(
+{{#if field.cpp_ref_not_boxed?}}{{#field}}{{#field.type}}{{> module_types_h/smart_ptr_constructor}}{{/field.type}}{{/field}}{{/if}}
+{{#if field.boxed_ref?}}{{#field}}{{#field.type}}{{> field/default}}{{/field.type}}{{/field}}{{/if}}
+  {{! TODO(dokwon): Support custom default for intern boxed field. }}
+{{#if field.intern_boxed_ref?}}{{field.cpp_storage_type}}::fromStaticConstant(&::apache::thrift::op::getDefault<{{#partial fields.tag field=field struct=struct:self}}>()){{/if}}
+  {{! Use value initialization when no custom default is provided. }}
+{{#if (not field.cpp_ref?)}}{{#field}}{{#field.type}}{{#field.default_value}}{{> field/default}}{{/field.default_value}}{{/field.type}}{{/field}}{{/if}}
+){{> common/comma_newline}}
+{{/each}}