Add initial pass of C++20 invocable map with Call operator.

This flavour no longer requires a clang extension and so should unlock other compilers. I'm keeping this in a separate CL since it's the first time both C++17 and C++20 versions for code in use and would like to flush out build failures. In a downstream CL I will add this to `ObjectRef` to enable the new syntax and eventually update existing usage. #42 PiperOrigin-RevId: 710778389
google · Dec 31, 2024 · 3c42766 · 3c42766
1 parent d855896
commit 3c42766
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Showing 13 changed files with 546 additions and 18 deletions.
diff --git a/.gitignore b/.gitignore
@@ -1 +1,2 @@
 bazel*
+.vscode
diff --git a/implementation/BUILD b/implementation/BUILD
@@ -923,8 +923,11 @@ cc_library(
         "//:jni_dep",
         "//implementation/jni_helper:lifecycle",
         "//metaprogramming:invocable_map",
+        "//metaprogramming:invocable_map_20",
         "//metaprogramming:queryable_map",
+        "//metaprogramming:queryable_map_20",
         "//metaprogramming:string_contains",
+        "//metaprogramming:string_literal",
     ],
 )
 
@@ -1237,9 +1240,10 @@ cc_library(
         ":method_selection",
         ":no_idx",
         "//:jni_dep",
-        "//implementation/jni_helper:invoke_static",
         "//metaprogramming:invocable_map",
+        "//metaprogramming:invocable_map_20",
         "//metaprogramming:queryable_map",
+        "//metaprogramming:queryable_map_20",
     ],
 )
 

diff --git a/implementation/class.h b/implementation/class.h
@@ -36,7 +36,10 @@ namespace jni {
 
 template <typename Extends_, typename Constructors_, typename Static_,
           typename Methods_, typename Fields_>
-struct Class {};
+struct Class {
+  constexpr Class() = default;
+  constexpr Class(const char* name) {}
+};
 
 template <typename Extends_, typename... Constructors_,
           typename... StaticMethods_, typename... StaticFields_,
@@ -70,6 +73,14 @@ struct Class<Extends_, std::tuple<Constructors_...>,
   // provided where they are and aren't present.
   ////////////////////////////////////////////////////////////////////////////////
 
+  // To stifle a test failure.
+  constexpr Class()
+      : Object("__JNI_BIND__NO_CLASS__"),
+        constructors_(Constructor<>{}),
+        static_(),
+        methods_(),
+        fields_() {}
+
   // Methods + Fields.
   explicit constexpr Class(const char* class_name, Methods_... methods,
                            Fields_... fields)

diff --git a/implementation/object_ref.h b/implementation/object_ref.h
@@ -34,8 +34,11 @@
 #include "implementation/ref_base.h"
 #include "jni_dep.h"
 #include "metaprogramming/invocable_map.h"
+#include "metaprogramming/invocable_map_20.h"
 #include "metaprogramming/queryable_map.h"
+#include "metaprogramming/queryable_map_20.h"
 #include "metaprogramming/string_contains.h"
+#include "metaprogramming/string_literal.h"
 
 namespace jni {
 
@@ -47,11 +50,17 @@ namespace jni {
 // operator[].
 template <typename JniT>
 class ObjectRef
+    // C++17 augmentations.
     : public metaprogramming::InvocableMap<
           ObjectRef<JniT>, JniT::stripped_class_v, typename JniT::ClassT,
           &JniT::ClassT::methods_>,
       public metaprogramming::QueryableMap_t<
           ObjectRef<JniT>, JniT::stripped_class_v, &JniT::ClassT::fields_>,
+      // C++ 20 augmentations.
+      public metaprogramming::InvocableMap20_t<
+          ObjectRef<JniT>, JniT::stripped_class_v, &JniT::ClassT::methods_>,
+      public metaprogramming::QueryableMap20_t<
+          ObjectRef<JniT>, JniT::stripped_class_v, &JniT::ClassT::fields_>,
       public RefBase<typename JniT::StorageType> {
  protected:
   static_assert(
@@ -83,6 +92,12 @@ class ObjectRef
 
   explicit ObjectRef(RefBaseT&& rhs) : RefBaseT(std::move(rhs)) {}
 
+  ////////////////////////////////////////////////////////////////////////////////
+  // Implementation: C++17 + clang
+  // Supports syntax like: "obj("foo", 123, args)", "obj["foo"].Get()"
+  // This syntax is less portable and may be removed in a major future release.
+  ////////////////////////////////////////////////////////////////////////////////
+#if __clang__
   // Invoked through CRTP from InvocableMap.
   template <size_t I, typename... Args>
   auto InvocableMapCall(const char* key, Args&&... args) const {
@@ -103,10 +118,41 @@ class ObjectRef
   auto QueryableMapCall(const char* key) const {
     return FieldRef<JniT, IdType::FIELD, I>{GetJClass(), RefBaseT::object_ref_};
   }
+#endif  // __clang__
+
+////////////////////////////////////////////////////////////////////////////////
+// C++20 Implementation (will only be included if supported).
+// Supports syntax like: "obj.Call<"foo">(123, args)",
+// "obj.Access<"foo">().Get()" Prefer using this syntax as they are more
+// portable.
+////////////////////////////////////////////////////////////////////////////////
+#if __cplusplus >= 202002L
+  // Invoked through CRTP from InvocableMap, C++20 only.
+  template <size_t I, metaprogramming::StringLiteral key_literal,
+            typename... Args>
+  auto InvocableMap20Call(Args&&... args) const {
+    using IdT = Id<JniT, IdType::OVERLOAD_SET, I, kNoIdx, kNoIdx, 0>;
+    using MethodSelectionForArgs =
+        OverloadSelector<IdT, IdType::OVERLOAD, IdType::OVERLOAD_PARAM,
+                         Args...>;
+
+    static_assert(MethodSelectionForArgs::kIsValidArgSet,
+                  "JNI Error: Invalid argument set.");
+
+    return MethodSelectionForArgs::OverloadRef::Invoke(
+        GetJClass(), RefBaseT::object_ref_, std::forward<Args>(args)...);
+  }
+
+  // Invoked through CRTP from QueryableMap20, C++20 only.
+  template <size_t I, metaprogramming::StringLiteral key_literal>
+  auto QueryableMap20Call() const {
+    return FieldRef<JniT, IdType::FIELD, I>{GetJClass(), RefBaseT::object_ref_};
+  }
+#endif  // __cplusplus >= 202002L
 };
 
 // Imbues constructors for ObjectRefs and handles calling the correct
-// intermediate constructors.  Access to this class is constrainted for non
+// intermediate constructors.  Access to this class is constrained for non
 // default classloaders (see |ValidatorProxy|).
 template <typename JniT>
 class ConstructorValidator : public ObjectRef<JniT> {

diff --git a/implementation/return.h b/implementation/return.h
@@ -31,7 +31,7 @@ struct Return : ReturnBase {
 
   using Raw = Raw_;
 
-  constexpr Return() = default;
+  constexpr Return() {}
 
   template <typename Raw>
   constexpr explicit Return(Raw raw) : raw_(raw) {}
@@ -42,7 +42,7 @@ struct Return<void> : ReturnBase {
   using Raw = void;
   const Void raw_{};
 
-  constexpr Return() = default;
+  constexpr Return() {}
 };
 
 Return() -> Return<void>;

diff --git a/implementation/static_ref.h b/implementation/static_ref.h
@@ -32,7 +32,9 @@
 #include "implementation/no_idx.h"
 #include "jni_dep.h"
 #include "metaprogramming/invocable_map.h"
+#include "metaprogramming/invocable_map_20.h"
 #include "metaprogramming/queryable_map.h"
+#include "metaprogramming/queryable_map_20.h"
 
 namespace jni {
 
@@ -41,13 +43,23 @@ template <typename CrtpBase_, const auto& class_v_, const auto& class_loader_v_,
 struct StaticRefHelper {
   using JniT = JniT<jobject, class_v_, class_loader_v_, jvm_v_>;
 
+  // C++17 augmentations.
   using MethodMapT = metaprogramming::InvocableMap<CrtpBase_, JniT::static_v,
                                                    typename JniT::StaticT,
                                                    &JniT::StaticT::methods_>;
   using FieldMapT = metaprogramming::QueryableMap_t<CrtpBase_, JniT::static_v,
                                                     &JniT::StaticT::fields_>;
+
+  // C++ 20 augmentations.
+  using MethodMap20T =
+      metaprogramming::InvocableMap20_t<CrtpBase_, JniT::static_v,
+                                        &JniT::StaticT::methods_>;
+  using FieldMap20T =
+      metaprogramming::QueryableMap20_t<CrtpBase_, JniT::static_v,
+                                        &JniT::StaticT::fields_>;
 };
 
+  // C++17 augmentations.
 template <typename CrtpBase_, const auto& class_v_, const auto& class_loader_v_,
           const auto& jvm_v_>
 using StaticRefHelperMethodMap_t =
@@ -60,21 +72,48 @@ using StaticRefHelperFieldMap_t =
     typename StaticRefHelper<CrtpBase_, class_v_, class_loader_v_,
                              jvm_v_>::FieldMapT;
 
+// C++20 augmentations.
+template <typename CrtpBase_, const auto& class_v_, const auto& class_loader_v_,
+          const auto& jvm_v_>
+using StaticRefHelperMethodMap20_t =
+    typename StaticRefHelper<CrtpBase_, class_v_, class_loader_v_,
+                             jvm_v_>::MethodMap20T;
+template <typename CrtpBase_, const auto& class_v_, const auto& class_loader_v_,
+          const auto& jvm_v_>
+using StaticRefHelperFieldMap20_t =
+    typename StaticRefHelper<CrtpBase_, class_v_, class_loader_v_,
+                             jvm_v_>::FieldMap20T;
+
 template <const auto& class_v_,
           const auto& class_loader_v_ = kDefaultClassLoader,
           const auto& jvm_v_ = kDefaultJvm>
 struct StaticRef
-    : public StaticRefHelperMethodMap_t<
+    : public
+      // C++17 augmentations.
+      StaticRefHelperMethodMap_t<
           StaticRef<class_v_, class_loader_v_, jvm_v_>, class_v_,
           class_loader_v_, jvm_v_>,
       StaticRefHelperFieldMap_t<StaticRef<class_v_, class_loader_v_, jvm_v_>,
-                                class_v_, class_loader_v_, jvm_v_> {
+                                class_v_, class_loader_v_, jvm_v_>,
+      // C++ 20 augmentations.
+      StaticRefHelperMethodMap20_t<
+          StaticRef<class_v_, class_loader_v_, jvm_v_>, class_v_,
+          class_loader_v_, jvm_v_>,
+      StaticRefHelperFieldMap20_t<StaticRef<class_v_, class_loader_v_, jvm_v_>,
+                                class_v_, class_loader_v_, jvm_v_>
+    {
   using JniT = JniT<jobject, class_v_, class_loader_v_, jvm_v_>;
 
   jclass GetJClass() const {
     return ClassRef_t<JniT>::GetAndMaybeLoadClassRef(nullptr);
   }
 
+  ////////////////////////////////////////////////////////////////////////////////
+  // Implementation: C++17 + clang
+  // Supports syntax like: "obj("foo", 123, args)", "obj["foo"].Get()"
+  // This syntax is less portable and may be removed in a major future release.
+  ////////////////////////////////////////////////////////////////////////////////
+#if __clang__
   template <size_t I, typename... Args>
   auto InvocableMapCall(const char* key, Args&&... args) const {
     using IdT = Id<JniT, IdType::STATIC_OVERLOAD_SET, I, kNoIdx, kNoIdx, 0>;
@@ -93,6 +132,32 @@ struct StaticRef
   auto QueryableMapCall(const char* key) const {
     return FieldRef<JniT, IdType::STATIC_FIELD, I>{GetJClass(), nullptr};
   }
+#endif  // __clang__
+
+#if __cplusplus >= 202002L
+  // Invoked through CRTP from InvocableMap, C++20 only.
+  template <size_t I, metaprogramming::StringLiteral key_literal,
+            typename... Args>
+  auto InvocableMap20Call(Args&&... args) const {
+    using IdT = Id<JniT, IdType::STATIC_OVERLOAD_SET, I, kNoIdx, kNoIdx, 0>;
+    using MethodSelectionForArgs =
+        OverloadSelector<IdT, IdType::STATIC_OVERLOAD,
+                         IdType::STATIC_OVERLOAD_PARAM, Args...>;
+
+    static_assert(MethodSelectionForArgs::kIsValidArgSet,
+                  "JNI Error: Invalid argument set.");
+
+    return MethodSelectionForArgs::OverloadRef::Invoke(
+        GetJClass(), nullptr, std::forward<Args>(args)...);
+  }
+
+  // Invoked through CRTP from QueryableMap20, C++20 only.
+  template <size_t I, metaprogramming::StringLiteral key_literal>
+  auto QueryableMap20Call() const {
+    return FieldRef<JniT, IdType::STATIC_FIELD, I>{GetJClass(), nullptr};
+  }
+#endif  // __cplusplus >= 202002L
+
 };
 
 }  // namespace jni

diff --git a/metaprogramming/BUILD b/metaprogramming/BUILD
@@ -605,6 +605,30 @@ cc_test(
     ],
 )
 
+################################################################################
+# Invocable Map 20.
+################################################################################
+cc_library(
+    name = "invocable_map_20",
+    hdrs = ["invocable_map_20.h"],
+    deps = [
+        ":modified_max",
+        ":string_literal",
+    ],
+)
+
+cc_test(
+    name = "invocable_map_test_20",
+    srcs = ["invocable_map_20_test.cc"],
+    tags = ["cpp20"],
+    deps = [
+        ":invocable_map_20",
+        ":modified_max",
+        ":string_literal",
+        "@googletest//:gtest_main",
+    ],
+)
+
 ################################################################################
 # Invoke.
 ################################################################################
@@ -961,6 +985,35 @@ cc_test(
     ],
 )
 
+################################################################################
+# Queryable Map 20.
+################################################################################
+cc_library(
+    name = "queryable_map_20",
+    hdrs = ["queryable_map_20.h"],
+    deps = [
+        ":interleave",
+        ":lambda_string",
+        ":modified_max",
+        ":string_literal",
+        ":tuple_from_size",
+        ":tuple_manipulation",
+        ":type_of_nth_element",
+    ],
+)
+
+cc_test(
+    name = "queryable_map_20_test",
+    srcs = ["queryable_map_20_test.cc"],
+    tags = ["cpp20"],
+    deps = [
+        ":modified_max",
+        ":queryable_map_20",
+        ":string_literal",
+        "@googletest//:gtest_main",
+    ],
+)
+
 ################################################################################
 # Reduce.
 ################################################################################