1 files changed, 138 insertions, 0 deletions
diff --git a/Lib/java/std_string_view.i b/Lib/java/std_string_view.i
new file mode 100644
index 000000000..005b9c0f8
--- /dev/null
+++ b/Lib/java/std_string_view.i
@@ -0,0 +1,138 @@
+/* -----------------------------------------------------------------------------
+ * std_string_view.i
+ *
+ * Typemaps for std::string_view and const std::string_view&
+ * These are mapped to a Java String and are passed around by value.
+ *
+ * To use non-const std::string_view references use the following %apply.  Note
+ * that they are passed by value.
+ * %apply const std::string_view & {std::string_view &};
+ * ----------------------------------------------------------------------------- */
+
+%{
+#include <string_view>
+#include <string>
+%}
+
+namespace std {
+
+%naturalvar string_view;
+
+class string_view;
+
+// string_view
+%typemap(jni) string_view "jstring"
+%typemap(jtype) string_view "String"
+%typemap(jstype) string_view "String"
+%typemap(javadirectorin) string_view "$jniinput"
+%typemap(javadirectorout) string_view "$javacall"
+
+%typemap(in) string_view
+%{ if(!$input) {
+     SWIG_JavaThrowException(jenv, SWIG_JavaNullPointerException, "null string");
+     return $null;
+   }
+   const char *$1_pstr = (const char *)jenv->GetStringUTFChars($input, 0);
+   if (!$1_pstr) return $null;
+   $1 = std::string_view($1_pstr); %}
+
+/* std::string_view requires the string data to remain valid while the
+ * string_view is in use. */
+%typemap(freearg) string_view
+%{ jenv->ReleaseStringUTFChars($input, $1_pstr); %}
+
+%typemap(directorout,warning=SWIGWARN_TYPEMAP_THREAD_UNSAFE_MSG) string_view
+%{ if(!$input) {
+     if (!jenv->ExceptionCheck()) {
+       SWIG_JavaThrowException(jenv, SWIG_JavaNullPointerException, "null string");
+     }
+     return $null;
+   }
+   const char *$1_pstr = (const char *)jenv->GetStringUTFChars($input, 0);
+   if (!$1_pstr) return $null;
+   /* possible thread/reentrant code problem */
+   static std::string $1_str;
+   $1_str = $1_pstr;
+   $result = std::string_view($1_str);
+   jenv->ReleaseStringUTFChars($input, $1_pstr); %}
+
+/* std::string_view::data() isn't zero-byte terminated, but NewStringUTF()
+ * requires a zero byte so it seems we have to make a copy (ick).  The
+ * cleanest way to do that seems to be via a temporary std::string.
+ */
+%typemap(directorin,descriptor="Ljava/lang/String;") string_view
+%{ $input = jenv->NewStringUTF(std::string($1).c_str());
+   Swig::LocalRefGuard $1_refguard(jenv, $input); %}
+
+%typemap(out) string_view
+%{ $result = jenv->NewStringUTF(std::string($1).c_str()); %}
+
+%typemap(javain) string_view "$javainput"
+
+%typemap(javaout) string_view {
+    return $jnicall;
+  }
+
+%typemap(typecheck) string_view = char *;
+
+%typemap(throws) string_view
+%{ SWIG_JavaThrowException(jenv, SWIG_JavaRuntimeException, std::string($1).c_str());
+   return $null; %}
+
+// const string_view &
+%typemap(jni) const string_view & "jstring"
+%typemap(jtype) const string_view & "String"
+%typemap(jstype) const string_view & "String"
+%typemap(javadirectorin) const string_view & "$jniinput"
+%typemap(javadirectorout) const string_view & "$javacall"
+
+%typemap(in) const string_view &
+%{ if(!$input) {
+     SWIG_JavaThrowException(jenv, SWIG_JavaNullPointerException, "null string");
+     return $null;
+   }
+   const char *$1_pstr = (const char *)jenv->GetStringUTFChars($input, 0);
+   if (!$1_pstr) return $null;
+   $*1_ltype $1_str($1_pstr);
+   $1 = &$1_str; %}
+
+/* std::string_view requires the string data to remain valid while the
+ * string_view is in use. */
+%typemap(freearg) const string_view &
+%{ jenv->ReleaseStringUTFChars($input, $1_pstr); %}
+
+%typemap(directorout,warning=SWIGWARN_TYPEMAP_THREAD_UNSAFE_MSG) const string_view &
+%{ if(!$input) {
+     SWIG_JavaThrowException(jenv, SWIG_JavaNullPointerException, "null string");
+     return $null;
+   }
+   const char *$1_pstr = (const char *)jenv->GetStringUTFChars($input, 0);
+   if (!$1_pstr) return $null;
+   /* possible thread/reentrant code problem */
+   static std::string $1_str;
+   $1_str = $1_pstr;
+   static $*1_ltype $1_strview;
+   $1_strview = $1_str;
+   $result = &$1_str;
+   jenv->ReleaseStringUTFChars($input, $1_pstr); %}
+
+%typemap(directorin,descriptor="Ljava/lang/String;") const string_view &
+%{ $input = jenv->NewStringUTF(std::string($1).c_str());
+   Swig::LocalRefGuard $1_refguard(jenv, $input); %}
+
+%typemap(out) const string_view &
+%{ $result = jenv->NewStringUTF(std::string(*$1).c_str()); %}
+
+%typemap(javain) const string_view & "$javainput"
+
+%typemap(javaout) const string_view & {
+    return $jnicall;
+  }
+
+%typemap(typecheck) const string_view & = char *;
+
+%typemap(throws) const string_view &
+%{ SWIG_JavaThrowException(jenv, SWIG_JavaRuntimeException, std::string($1).c_str());
+   return $null; %}
+
+}