Implement rb_str_locktmp and rb_str_unlocktmp

Author: bjfish

optional/capi/ext/string_spec.c

@@ -577,6 +577,14 @@ static VALUE string_spec_rb_str_catf(VALUE self, VALUE mesg) {
   return rb_str_catf(mesg, "fmt %d %d number", 41, 6);
 }
 
+static VALUE string_spec_rb_str_locktmp(VALUE self, VALUE str) {
+  return rb_str_locktmp(str);
+}
+
+static VALUE string_spec_rb_str_unlocktmp(VALUE self, VALUE str) {
+  return rb_str_unlocktmp(str);
+}
+
 void Init_string_spec(void) {
   VALUE cls = rb_define_class("CApiStringSpecs", rb_cObject);
   rb_define_method(cls, "rb_cstr2inum", string_spec_rb_cstr2inum, 2);
@@ -672,6 +680,8 @@ void Init_string_spec(void) {
   rb_define_method(cls, "rb_utf8_str_new_cstr", string_spec_rb_utf8_str_new_cstr, 0);
   rb_define_method(cls, "rb_str_vcatf", string_spec_rb_str_vcatf, 1);
   rb_define_method(cls, "rb_str_catf", string_spec_rb_str_catf, 1);
+  rb_define_method(cls, "rb_str_locktmp", string_spec_rb_str_locktmp, 1);
+  rb_define_method(cls, "rb_str_unlocktmp", string_spec_rb_str_unlocktmp, 1);
 }
 
 #ifdef __cplusplus

optional/capi/string_spec.rb

@@ -1209,4 +1209,31 @@ def inspect
       str.should == "test fmt 41 6 number"
     end
   end
+
+  describe "rb_str_locktmp" do
+    it "raises an error when trying to lock an already locked string" do
+      str = "test"
+      @s.rb_str_locktmp(str).should == str
+      -> { @s.rb_str_locktmp(str) }.should raise_error(RuntimeError, 'temporal locking already locked string')
+    end
+
+    it "locks a string so that modifications would raise an error" do
+      str = "test"
+      @s.rb_str_locktmp(str).should == str
+      -> { str.upcase! }.should raise_error(RuntimeError, 'can\'t modify string; temporarily locked')
+    end
+  end
+
+  describe "rb_str_unlocktmp" do
+    it "unlocks a locked string" do
+      str = "test"
+      @s.rb_str_locktmp(str)
+      @s.rb_str_unlocktmp(str).should == str
+      str.upcase!.should == "TEST"
+    end
+
+    it "raises an error when trying to unlock an already unlocked string" do
+      -> { @s.rb_str_unlocktmp("test") }.should raise_error(RuntimeError, 'temporal unlocking already unlocked string')
+    end
+  end
 end