check enc_capable.

* encoding.c (rb_enc_capable): make it extern to check enc_capable.
  enc_index can be set to limited types such as T_STRING, T_REGEX
  and so on. This function check an object is this kind of types.

* include/ruby/encoding.h: ditto.

* encoding.c (enc_set_index): check a given object is enc_capable.

* include/ruby/encoding.h (PUREFUNC):

* marshal.c (encoding_name): check `rb_enc_capable` first.

* marshal.c (r_ivar): ditto. If it is not enc_capable, it should be
  malformed data.

* spec/ruby/optional/capi/encoding_spec.rb: remove tests depending
  on the wrong feature: all objects can set enc_index.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63777 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

encoding.c

@@ -756,6 +756,12 @@ enc_capable(VALUE obj)
     }
 }
 
+int
+rb_enc_capable(VALUE obj)
+{
+    return enc_capable(obj);
+}
+
 ID
 rb_id_encoding(void)
 {
@@ -813,6 +819,8 @@ rb_enc_get_index(VALUE obj)
 static void
 enc_set_index(VALUE obj, int idx)
 {
+    if (!enc_capable(obj)) rb_bug("enc_set_index: not capable object");
+
     if (idx < ENCODING_INLINE_MAX) {
 	ENCODING_SET_INLINED(obj, idx);
 	return;

include/ruby/encoding.h

@@ -122,6 +122,7 @@ PUREFUNC(int rb_enc_dummy_p(rb_encoding *enc));
 PUREFUNC(int rb_enc_to_index(rb_encoding *enc));
 int rb_enc_get_index(VALUE obj);
 void rb_enc_set_index(VALUE obj, int encindex);
+int rb_enc_capable(VALUE obj);
 int rb_enc_find_index(const char *name);
 int rb_to_encoding_index(VALUE);
 rb_encoding *rb_to_encoding(VALUE);

marshal.c

@@ -578,29 +578,34 @@ obj_count_ivars(st_data_t key, st_data_t val, st_data_t a)
 static VALUE
 encoding_name(VALUE obj, struct dump_arg *arg)
 {
-    int encidx = rb_enc_get_index(obj);
-    rb_encoding *enc = 0;
-    st_data_t name;
+    if (rb_enc_capable(obj)) {
+        int encidx = rb_enc_get_index(obj);
+        rb_encoding *enc = 0;
+        st_data_t name;
 
-    if (encidx <= 0 || !(enc = rb_enc_from_index(encidx))) {
-	return Qnil;
-    }
+        if (encidx <= 0 || !(enc = rb_enc_from_index(encidx))) {
+            return Qnil;
+        }
 
-    /* special treatment for US-ASCII and UTF-8 */
-    if (encidx == rb_usascii_encindex()) {
-	return Qfalse;
-    }
-    else if (encidx == rb_utf8_encindex()) {
-	return Qtrue;
-    }
+        /* special treatment for US-ASCII and UTF-8 */
+        if (encidx == rb_usascii_encindex()) {
+            return Qfalse;
+        }
+        else if (encidx == rb_utf8_encindex()) {
+            return Qtrue;
+        }
 
-    if (arg->encodings ?
-	!st_lookup(arg->encodings, (st_data_t)rb_enc_name(enc), &name) :
-	(arg->encodings = st_init_strcasetable(), 1)) {
-	name = (st_data_t)rb_str_new_cstr(rb_enc_name(enc));
-	st_insert(arg->encodings, (st_data_t)rb_enc_name(enc), name);
+        if (arg->encodings ?
+            !st_lookup(arg->encodings, (st_data_t)rb_enc_name(enc), &name) :
+            (arg->encodings = st_init_strcasetable(), 1)) {
+            name = (st_data_t)rb_str_new_cstr(rb_enc_name(enc));
+            st_insert(arg->encodings, (st_data_t)rb_enc_name(enc), name);
+        }
+        return (VALUE)name;
+    }
+    else {
+        return Qnil;
     }
-    return (VALUE)name;
 }
 
 static void
@@ -1486,7 +1491,12 @@ r_ivar(VALUE obj, int *has_encoding, struct load_arg *arg)
 	    VALUE val = r_object(arg);
 	    int idx = sym2encidx(sym, val);
 	    if (idx >= 0) {
-		rb_enc_associate_index(obj, idx);
+                if (rb_enc_capable(obj)) {
+                    rb_enc_associate_index(obj, idx);
+                }
+                else {
+                    rb_raise(rb_eArgError, "%"PRIsVALUE" is not enc_capable", obj);
+                }
 		if (has_encoding) *has_encoding = TRUE;
 	    }
 	    else {

spec/ruby/optional/capi/encoding_spec.rb

@@ -12,24 +12,6 @@ describe :rb_enc_get_index, shared: true do
   it "returns the index of the encoding of a Regexp" do
     @s.send(@method, /regexp/).should >= 0
   end
-
-  it "returns the index of the encoding of an Object" do
-    obj = mock("rb_enc_get_index string")
-    @s.rb_enc_set_index(obj, 1)
-    @s.send(@method, obj).should == 1
-  end
-
-  it "returns the index of the dummy encoding of an Object" do
-    obj = mock("rb_enc_get_index string")
-    index = Encoding.list.index(Encoding::UTF_16)
-    @s.rb_enc_set_index(obj, index)
-    @s.send(@method, obj).should == index
-  end
-
-  it "returns 0 for an object without an encoding" do
-    obj = mock("rb_enc_get_index string")
-    @s.send(@method, obj).should == 0
-  end
 end
 
 describe :rb_enc_set_index, shared: true do
@@ -48,12 +30,6 @@ describe :rb_enc_set_index, shared: true do
     result = @s.send(@method, str, 1)
     result.first.should == result.last
   end
-
-  it "associates an encoding with an object" do
-    obj = mock("rb_enc_set_index string")
-    result = @s.send(@method, obj, 1)
-    result.first.should == result.last
-  end
 end
 
 describe "C-API Encoding function" do