Experimenting with string literals for non-type template parameters.

BUILD

@@ -111,6 +111,7 @@ cc_library(
     name = "jni_test",
     testonly = 1,
     hdrs = ["jni_test.h"],
+    tags = ["nozapfhahn"],
     visibility = [":__subpackages__"],
     deps = [
         ":jni_bind",
@@ -124,6 +125,7 @@ cc_library(
     name = "mock_jni_env",
     testonly = 1,
     hdrs = ["mock_jni_env.h"],
+    tags = ["nozapfhahn"],
     visibility = [":__subpackages__"],
     deps = [
         "//:jni_dep",
@@ -135,6 +137,7 @@ cc_library(
     name = "mock_jvm",
     testonly = 1,
     hdrs = ["mock_jvm.h"],
+    tags = ["nozapfhahn"],
     visibility = [":__subpackages__"],
     deps = [
         "//:jni_dep",

javatests/com/jnibind/test/BUILD

@@ -32,6 +32,7 @@ java_test(
     srcs = ["ArrayTestFieldRank1.java"],
     data = [":libarray_test_field_rank_1_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     runtime_deps = [":array_test_helpers"],
     deps = [
         ":object_test_helper",
@@ -69,6 +70,7 @@ java_test(
     srcs = ["ArrayTestFieldRank2.java"],
     data = [":libarray_test_field_rank_2_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     runtime_deps = [
         ":array_test_helpers",
     ],
@@ -133,6 +135,7 @@ java_test(
     srcs = ["ArrayTestMethodRank1.java"],
     data = [":libarray_test_method_rank_1_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     runtime_deps = [
         ":array_test_helpers",
     ],
@@ -173,6 +176,7 @@ java_test(
     srcs = ["ArrayTestMethodRank2.java"],
     data = [":libarray_test_method_rank_2_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     runtime_deps = [
         ":array_test_helpers",
     ],
@@ -210,6 +214,7 @@ java_test(
     srcs = ["BuilderTest.java"],
     data = [":libbuilder_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     deps = [
         ":object_test_helper",
         "@maven//:junit_junit",
@@ -261,6 +266,7 @@ java_test(
         ":libclass_loader_test_jni.so",
     ],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     deps = ["@maven//:junit_junit"],
 )
 
@@ -290,6 +296,7 @@ java_test(
     srcs = ["ContextTest.java"],
     data = [":libcontext_test_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     deps = [
         ":object_test_helper",
         "@maven//:com_google_truth_truth",
@@ -328,6 +335,7 @@ java_test(
     ],
     data = [":libfield_test_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     deps = [
         "@maven//:com_google_truth_truth",
         "@maven//:junit_junit",
@@ -362,6 +370,7 @@ java_test(
     srcs = ["GlobalObjectTest.java"],
     data = [":libglobal_object_test_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     deps = [
         ":object_test_helper",
         "@maven//:com_google_truth_truth",
@@ -377,6 +386,7 @@ cc_library(
     testonly = True,
     srcs = ["local_object_test_jni.cc"],
     defines = ["ENABLE_DEBUG_OUTPUT"],
+    tags = ["nosan"],
     deps = [
         ":object_test_helper_jni",
         "//:jni_bind",
@@ -397,6 +407,7 @@ java_test(
     srcs = ["LocalObjectTest.java"],
     data = [":liblocal_object_test_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     deps = [
         ":object_test_helper",
         "@maven//:com_google_truth_truth",
@@ -435,6 +446,7 @@ java_test(
     ],
     data = [":libmethod_test_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     deps = [
         "@maven//:com_google_truth_truth",
         "@maven//:junit_junit",
@@ -505,6 +517,7 @@ java_test(
     ],
     data = [":libstatic_test_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     deps = [
         ":object_test_helper",
         "@maven//:com_google_truth_truth",
@@ -543,6 +556,7 @@ java_test(
     ],
     data = [":libstring_test_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     deps = [
         "@maven//:com_google_truth_truth",
         "@maven//:junit_junit",
@@ -577,6 +591,7 @@ java_test(
     srcs = ["ThreadTest.java"],
     data = [":libthread_test_jni.so"],
     jvm_flags = ["-Djava.library.path=./javatests/com/jnibind/test"],
+    tags = ["nosan"],
     runtime_deps = [":array_test_helpers"],
     deps = [
         ":object_test_helper",

metaprogramming/BUILD

@@ -1111,6 +1111,24 @@ cc_test(
     ],
 )
 
+################################################################################
+# String Literal.
+################################################################################
+cc_library(
+    name = "string_literal",
+    hdrs = ["string_literal.h"],
+)
+
+cc_test(
+    name = "string_literal_test",
+    srcs = ["string_literal_test.cc"],
+    tags = ["cpp20"],
+    deps = [
+        ":string_literal",
+        "@googletest//:gtest_main",
+    ],
+)
+
 ################################################################################
 # Type Index Mask.
 ################################################################################
@@ -1238,6 +1256,7 @@ cc_library(
 cc_test(
     name = "vals_equal_test",
     srcs = ["vals_equal_test.cc"],
+    tags = ["manual"],
     deps = [
         ":vals",
         ":vals_equal",

metaprogramming/string_literal.h

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * 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.
+ */
+
+#ifndef JNI_BIND_METAPROGRAMMING_STRING_LITERAL_H_
+#define JNI_BIND_METAPROGRAMMING_STRING_LITERAL_H_
+
+#ifdef __cplusplus
+#if __cplusplus >= 202002L
+
+#include <algorithm>
+#include <cstddef>
+#include <string_view>
+
+namespace jni::metaprogramming {
+
+// Inspired by Kevin Hartman's StringLiteral implementation.
+// https://ctrpeach.io/posts/cpp20-string-literal-template-parameters/
+//
+// This class is not currently being used, but is being used to prototype
+// changes that will be needed for consumers of `InvocableMap`. This class is
+// not included by default for build because it requires C++20.
+template <size_t N>
+struct StringLiteral {
+  constexpr StringLiteral(const char (&str)[N]) { std::copy_n(str, N, value); }
+
+  constexpr StringLiteral<N> Self() { return *this; }
+
+  template <std::size_t U>
+  constexpr bool operator==(const StringLiteral<U>& rhs) const {
+    if constexpr (N != U) {
+      return false;
+    } else {
+      return std::string_view{value} == std::string_view{rhs.value};
+    }
+  }
+
+  template <std::size_t U>
+  constexpr bool operator!=(const StringLiteral<U>& rhs) const {
+    return !(*this == rhs);
+  }
+
+  char value[N];
+};
+
+template <size_t N>
+StringLiteral(const char (&str)[N]) -> StringLiteral<N>;
+
+#endif  // __cplusplus >= 202002L
+#endif  // __cplusplus
+
+}  // namespace jni::metaprogramming
+
+#endif  // JNI_BIND_METAPROGRAMMING_STRING_LITERAL_H_

metaprogramming/string_literal_test.cc

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * 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.
+ */
+
+#include "string_literal.h"
+
+#include <cstddef>
+
+using jni::metaprogramming::StringLiteral;
+
+namespace {
+
+template <size_t N>
+constexpr StringLiteral<N> Foo(const char (&str)[N]) {
+  StringLiteral b{str};
+  return b;
+}
+
+// String literals can now peer through callsites. This was previously not
+// possible in C++17 and should hopefully simplify method selection.
+static_assert(Foo("Testing") == StringLiteral{"Testing"});
+static_assert(Foo("abcdefg") != StringLiteral{"Testing"});
+static_assert(Foo("Testing") != StringLiteral{"abcdefg"});
+static_assert(Foo("Bar") != StringLiteral{"Testing"});
+static_assert(Foo("Testing") != StringLiteral{"Bar"});
+
+// This represents a container class. Any classes currently constructed with
+// const char* will need to migrate to this new form which explicitly captures
+// length.
+template <std::size_t N>
+struct SampleContainer {
+  constexpr SampleContainer(const char (&val_)[N]) : val_(val_) {}
+
+  StringLiteral<N> val_;
+};
+
+template <std::size_t N>
+SampleContainer(const char (&val_)[N]) -> SampleContainer<N>;
+
+static_assert(SampleContainer("Testing").val_ == StringLiteral{"Testing"});
+static_assert(SampleContainer("abcdefg").val_ != StringLiteral{"Testing"});
+static_assert(SampleContainer("Foo").val_ != StringLiteral{"Testing"});
+
+}  // namespace