[cffi-devel] Error with translate-to-foreign

[Greg Pfeil]

This is using the latest darcs cffi on SBCL 0.9.5 ...

I have a list of lists of strings and have created the translations 
below (the arrays end up null-terminated):

(defctype string-list :pointer)
(defctype string-lists :pointer)

(defmethod translate-to-foreign (value (type (eql 'string-list)))
   (let ((foreign (foreign-alloc :string
                                 :initial-contents value
                                 :count (1+ (length value)))))
     (setf (mem-aref foreign :pointer (length value)) (null-pointer))
     foreign))

(defmethod translate-to-foreign (value (type (eql 'string-lists)))
   (let ((foreign (foreign-alloc 'string-list
                                 :initial-contents value
                                 :count (1+ (length value)))))
     (setf (mem-aref foreign :pointer (length value)) (null-pointer))
     foreign))

I get an error on the call to t-t-f for string-list, because the value 
is a pointer and not a sequence. If I change the foreign-alloc type to 
:pointer instead of string-list, it compalains that ("foo" "bar") is 
not a pointer (which makes sense).

So, using 'string-list seems to try to double-convert (which I don't 
expect), :pointer seems to not convert at all (which I do expect). So, 
any idea what I'm doing wrong?

Here's the error:

   0: (LENGTH #.(SB-SYS:INT-SAP #X082CCA70))
   1: ((SB-PCL::FAST-METHOD CFFI:TRANSLATE-TO-FOREIGN (T (EQL (QUOTE 
PRODUCT-DISC
OVERY::STRING-LIST)))) #<unavailable argument> #<unavailable argument> 
#.(SB-SYS
:INT-SAP #X082CCA70) #<unavailable argument>)
   2: ((SB-PCL::FAST-METHOD CFFI::TRANSLATE-TYPE-TO-FOREIGN (T 
CFFI::FOREIGN-TYPE
DEF)) #<unavailable argument> #<unavailable argument> #.(SB-SYS:INT-SAP 
#X082CCA
70) #<CFFI::FOREIGN-TYPEDEF PRODUCT-DISCOVERY::STRING-LIST>)
   3: (CFFI::MEM-SET #.(SB-SYS:INT-SAP #X082CCA70) #.(SB-SYS:INT-SAP 
#X082CD488)
PRODUCT-DISCOVERY::STRING-LIST 0)
   4: (CFFI:FOREIGN-ALLOC PRODUCT-DISCOVERY::STRING-LIST 
:INITIAL-ELEMENT NIL :IN
ITIAL-CONTENTS (("ASIN" "B0002E3MRW")) :COUNT 2)
   5: ((SB-PCL::FAST-METHOD CFFI:TRANSLATE-TO-FOREIGN (T (EQL (QUOTE 
PRODUCT-DISC
OVERY::STRING-LISTS)))) #<unavailable argument> #<unavailable argument> 
(("ASIN"
  "B0002E3MRW")) #<unavailable argument>)
   6: ((SB-PCL::FAST-METHOD CFFI::TRANSLATE-TYPE-TO-FOREIGN (T 
CFFI::FOREIGN-TYPE
DEF)) #<unavailable argument> #<unavailable argument> (("ASIN" 
"B0002E3MRW")) #<
CFFI::FOREIGN-TYPEDEF PRODUCT-DISCOVERY::STRING-LISTS>)