[armedbear-devel] Bug in translate-logical-pathname.
Thomas Russ
tar at ISI.EDU
Mon Nov 16 20:14:33 UTC 2009
There seems to be a bug in TRANSLATE-LOGICAL-PATHNAME when the logical
pathname source includes constant elements in addition to wildcards.
Here is an example that demonstrates the problem:
CL-USER(1): (setf (logical-pathname-translations "L")
'(("L:NATIVE;**;*.*" "/usr/lisp/abcl/native/**/*.*")))
((#P"L:NATIVE;**;*.*" #P"/usr/lisp/abcl/native/**/*.*"))
CL-USER(2): (translate-logical-pathname "L:NATIVE;TEST;FOO.FASL")
#P"/usr/lisp/abcl/native/native/test/foo.fasl"
;; ERROR. Should be #P"/usr/lisp/abcl/native/test/foo.fasl"
;;
;; With :wild-inferiors, the full directory path is copied instead of
;; just the part after the matching constant part. That results in
;; the "native" element appearing twice.
;;
The problem seems to be in the file "abcl/src/org/armedbear/lisp/
pathnames.lisp", in the function SYSTEM::TRANSLATE-DIRECTORY-COMPONENTS:
(defun translate-directory-components (source from to case)
(cond ((null to)
nil
)
((memq (car to) '(:absolute :relative))
(cons (car to)
(translate-directory-components (cdr source) (cdr
from) (cdr to) case))
)
((eq (car to) :wild)
(if (eq (car from) :wild)
;; Grab the next chunk from SOURCE.
(append (casify (car source) case)
(translate-directory-components (cdr source)
(cdr from) (cdr to) case))
(error "Unsupported case 1: ~S ~S ~S" source from to))
)
((eq (car to) :wild-inferiors)
;; Grab the next chunk from SOURCE.
(append (casify (car source) case)
(translate-directory-components (cdr source) (cdr
from) (cdr to) case))
)
(t
;; "If the piece in TO-WILDCARD is present and not wild, it
is copied
;; into the result."
(append (casify (car to) case)
(translate-directory-components source from (cdr to)
case))
)
))
The final COND clause ("T") needs to be more sophisticated in what it
does. If there are non-wildcard elements in the FROM, then it will
need to eliminate the the common prefix between "source" and "from".
In order to be a valid match, it I think it SHOULD be guaranteed that
a non-wildcard "from" component is a leading subsequence or equal to
"source" -- but I'm not fully familiar with the code, but a quick test
seems to indicate that the following modified function covers at least
the simpler cases of this issue. It adds a new clause checking
for :WILD-INFERIORS in the FROM slot which performs the current
function, and changes the T clause to properly manage the subsequence
matching.
(defun translate-directory-components (source from to case)
(cond ((null to)
nil
)
((memq (car to) '(:absolute :relative))
(cons (car to)
(translate-directory-components (cdr source) (cdr
from) (cdr to) case))
)
((eq (car to) :wild)
(if (eq (car from) :wild)
;; Grab the next chunk from SOURCE.
(append (casify (car source) case)
(translate-directory-components (cdr source)
(cdr from) (cdr to) case))
(error "Unsupported case 1: ~S ~S ~S" source from to))
)
((eq (car to) :wild-inferiors)
;; Grab the next chunk from SOURCE.
(append (casify (car source) case)
(translate-directory-components (cdr source) (cdr
from) (cdr to) case))
)
((eq (car from) :wild-inferiors)
;; "If the piece in TO-WILDCARD is present and not wild, and
the FROM item
;; doesn't contain any constants, then just copy TO to the result."
(append (casify (car to) case)
(translate-directory-components source from (cdr to)
case)))
(t
;; "If the piece in TO-WILDCARD is present and not wild,
then FROM should
;; be a subsequence of SOURCE. The common subsequence
needs to be removed
;; in the recursive call. Special case handling for a full
match is
;; also needed."
(let ((pos (mismatch (car source) (car from) :test #'string-
equal)))
(append (casify (car to) case)
(if (null pos) ;; A full match, pop both source
and from
(translate-directory-components (cdr source)
(cdr from) (cdr to) case)
(translate-directory-components (cons (subseq
(car source) pos) (cdr source)) (cdr from) (cdr to) case))))
)
))
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