[android] - replace platform default implementation using nunicode fo…

…r uppercasing an lowercasing with an Android specific String.java equivalent

platform/android/config.cmake

@@ -38,7 +38,7 @@ macro(mbgl_platform_core)
         PRIVATE platform/android/src/text/local_glyph_rasterizer_jni.hpp
         PRIVATE platform/android/src/logging_android.cpp
         PRIVATE platform/android/src/thread.cpp
-        PRIVATE platform/default/string_stdlib.cpp
+        PRIVATE platform/android/src/string_stdlib.cpp
         PRIVATE platform/default/bidi.cpp
         PRIVATE platform/default/thread_local.cpp
         PRIVATE platform/default/unaccent.cpp

platform/android/src/java/lang.cpp

@@ -5,6 +5,30 @@ namespace android {
 namespace java {
 namespace lang {
 
+// String
+
+jni::Object<String> String::New(JNIEnv& env, jni::String value) {
+    static auto constructor = String::javaClass.GetConstructor<jni::String>(env);
+    return String::javaClass.New(env, constructor, value);
+}
+
+jni::String String::toUpperCase(JNIEnv& env, jni::String value) {
+    static auto method = javaClass.GetMethod<jni::String ()>(env, "toUpperCase");
+    return String::New(env, value).Call(env, method);
+}
+
+jni::String String::toLowerCase(JNIEnv& env, jni::String value) {
+    static auto method = javaClass.GetMethod<jni::String ()>(env, "toLowerCase");
+    return String::New(env, value).Call(env, method);
+}
+
+void String::registerNative(jni::JNIEnv& env) {
+    // Lookup the class
+    javaClass = *jni::Class<String>::Find(env).NewGlobalRef(env).release();
+}
+
+jni::Class<String> String::javaClass;
+
 // Float
 
 jni::Object<Float> Float::valueOf(JNIEnv &env, jfloat value) {

platform/android/src/java/lang.hpp

@@ -8,6 +8,21 @@ namespace android {
 namespace java {
 namespace lang {
 
+class String : private mbgl::util::noncopyable {
+public:
+    static constexpr auto Name() { return "java/lang/String"; };
+
+    static jni::Object<String> New(JNIEnv&, jni::String);
+
+    static jni::String toUpperCase(JNIEnv&, jni::String);
+
+    static jni::String toLowerCase(JNIEnv&, jni::String);
+
+    static jni::Class<String> javaClass;
+
+    static void registerNative(jni::JNIEnv&);
+};
+
 class Float : private mbgl::util::noncopyable {
 public:
     static constexpr auto Name() { return "java/lang/Float"; };

platform/android/src/jni.cpp

@@ -119,6 +119,7 @@ void registerNatives(JavaVM *vm) {
     java::lang::Boolean::registerNative(env);
     java::lang::Double::registerNative(env);
     java::lang::Long::registerNative(env);
+    java::lang::String::registerNative(env);
 
     // GeoJSON
     geojson::Feature::registerNative(env);

platform/android/src/string_stdlib.cpp

@@ -0,0 +1,21 @@
+#include <mbgl/util/platform.hpp>
+#include "java/lang.hpp"
+#include "attach_env.hpp"
+
+namespace mbgl {
+namespace platform {
+
+std::string uppercase(const std::string& str) {
+    auto env{ android::AttachEnv() };
+    auto jstring = jni::Make<jni::String>(*env, str.c_str());
+    return jni::Make<std::string>(*env, mbgl::android::java::lang::String::toUpperCase(*env, jstring));
+}
+
+std::string lowercase(const std::string& str) {
+    auto env{ android::AttachEnv() };
+    auto jstring = jni::Make<jni::String>(*env, str.c_str());
+    return jni::Make<std::string>(*env, mbgl::android::java::lang::String::toLowerCase(*env, jstring));
+}
+
+} // namespace platform
+} // namespace mbgl