[php] Support INPUT,INOUT,OUTPUT for std::string&

By default SWIG/PHP wraps std::string& as a pass-by-reference PHP
string parameter, but sometimes such a parameter is only for input
or only for output, so add support for the named typemaps that other
target languages support.

2 files changed, 36 insertions, 2 deletions

diff --git a/Examples/test-suite/li_std_string.i b/Examples/test-suite/li_std_string.i
index 47a9090b7..209cf883f 100644
--- a/Examples/test-suite/li_std_string.i
+++ b/Examples/test-suite/li_std_string.i
@@ -1,9 +1,10 @@
 %module li_std_string
 %include <std_string.i>
 
-#if defined(SWIGUTL)
+#if defined(SWIGPHP) || defined(SWIGUTL)
 %apply std::string& INPUT { std::string &input }
 %apply std::string& INOUT { std::string &inout }
+%apply std::string& OUTPUT { std::string &output }
 #endif
 
 // throw is invalid in C++17 and later, only SWIG to use it
@@ -53,13 +54,28 @@ std::string& test_reference_out() {
 }
 
 std::string test_reference_input(std::string &input) {
-  return input;
+  // For PHP to allow checking that we haven't used the default string&
+  // typemap which wraps as a PHP pass-by-reference string parameter.
+  std::string copy = input;
+  input = "MODIFIED";
+  return copy;
 }
 
 void test_reference_inout(std::string &inout) {
   inout += inout;
 }
 
+void test_reference_output(std::string &output) {
+  output = "output";
+}
+
+#ifdef SWIGPHP
+// Test PHP-specific default wrapping string& as pass-by-ref PHP string.
+void test_reference_php(std::string &s) {
+  s += ".php";
+}
+#endif
+
 void test_throw() TESTCASE_THROW1(std::string){
   static std::string x = "test_throw message";
   throw x;
diff --git a/Examples/test-suite/php/li_std_string_runme.php b/Examples/test-suite/php/li_std_string_runme.php
index 680b7ce98..169f947a7 100644
--- a/Examples/test-suite/php/li_std_string_runme.php
+++ b/Examples/test-suite/php/li_std_string_runme.php
@@ -49,6 +49,24 @@ Structure::StaticMemberString2($s);
 check::equal(Structure::StaticMemberString2(), $s, "StaticMemberString2 test 2");
 check::equal(Structure::ConstStaticMemberString(), "const static member string", "ConstStaticMemberString test");
 
+// Test INPUT, INOUT and OUTPUT string& typemaps:
+$input = "hello";
+check::equal(li_std_string::test_reference_input($input), "hello");
+// $input should be unchanged - this check is to catch if we incorrectly used
+// the default string& typemap:
+check::equal($input, "hello");
+$s = li_std_string::test_reference_inout($input);
+check::equal($s, "hellohello");
+// $input should be unchanged - this check is to catch if we incorrectly used
+// the default string& typemap:
+check::equal($input, "hello");
+check::equal(li_std_string::test_reference_output(), "output");
+
+// Test default PHP wrapping of std::string& as a by-ref PHP string parameter:
+$s = "byref";
+check::equal(li_std_string::test_reference_php($s), null);
+check::equal($s, "byref.php");
+
 // This used to give "Undefined variable: r"
 li_std_string::test_const_reference_returning_void("foo");