ffi: handle copy flag in str type's in virtual.

This solves the second issue described in parent
commit. When a str type is passed in-out using
(ptr str) in a struct or array, the struct or array
is not picking up the new string. The pointer is
freed, but the old object persists.

* ffi.c (ffi_str_in): Function renamed to ffi_str_in.  If the
copy flag is true, retrieves a string from the pointer and
that string is returned instead of the incoming one, mapping a
null pointer to nil.  Either way, the pointer is freed.  Since
ffi_ptr_out_in passes 1 for the copy flag, that ensures we
extract the new string and plant it into the array.

1 files changed, 6 insertions, 4 deletions

diff --git a/ffi.c b/ffi.c
index b295e989..c4d3ee23 100644
--- a/ffi.c
+++ b/ffi.c
@@ -564,10 +564,12 @@ static mem_t *ffi_cptr_alloc(struct txr_ffi_type *tft, val ptr, val self)
   return coerce(mem_t *, cptr_addr_of(ptr));
 }
 
-static val ffi_freeing_in(struct txr_ffi_type *tft, int copy,
-                          mem_t *src, val obj, val self)
+static val ffi_str_in(struct txr_ffi_type *tft, int copy,
+                      mem_t *src, val obj, val self)
 {
-  mem_t **loc = coerce(mem_t **, src);
+  char **loc = coerce(char **, src);
+  if (copy)
+    obj = if2(*loc, string_utf8(*loc));
   free(*loc);
   *loc = 0;
   return obj;
@@ -1517,7 +1519,7 @@ static void ffi_init_types(void)
                                      &ffi_type_pointer,
                                      ffi_str_put, ffi_str_get);
     struct txr_ffi_type *tft = ffi_type_struct(type);
-    tft->in = ffi_freeing_in;
+    tft->in = ffi_str_in;
     ffi_typedef(str_s, type);
   }