change `transplant-{input,output}-port' to propagate buffering

Affects derived functions, such as `dup-output-port' and
`relocate-output-port', and uses in `pretty-print'.

collects/racket/port.rkt

@@ -623,7 +623,10 @@
           (lambda (n evt target-evt) (port-commit-peeked n evt target-evt p)))
      location-proc
      count-lines!-proc
-     pos)))
+     pos
+     (case-lambda
+      [(mode) (file-stream-buffer-mode p mode)]
+      [() (file-stream-buffer-mode p)]))))
 
 (define filter-read-input-port
   (lambda (p wrap-read wrap-peek [close? #t])

collects/racket/private/port.rkt

@@ -56,15 +56,21 @@
      (object-name p)
      p
      (lambda (s start end nonblock? breakable?)
-       (let ([v ((if nonblock? 
-                     write-bytes-avail*
-                     (if breakable?
-                         write-bytes-avail/enable-break
-                         write-bytes-avail))
-                 s p start end)])
-         (if (and (zero? v) (not (= start end)))
-             (wrap-evt p (lambda (x) #f))
-             v)))
+       (if (= start end)
+           (parameterize-break
+            breakable?
+            (flush-output p)
+            0)
+           (let ([v (if nonblock? 
+                        (write-bytes-avail* s p start end)
+                        (if breakable?
+                            (parameterize-break
+                             #t
+                             (write-bytes s p start end))
+                            (write-bytes s p start end)))])
+             (if (and (zero? v) (not (= start end)))
+                 (wrap-evt p (lambda (x) #f))
+                 v))))
      (lambda ()
        (when close?
          (close-output-port p)))
@@ -87,7 +93,10 @@
             (write-special-evt spec p)))
      location-proc
      count-lines!-proc
-     pos)))
+     pos
+     (case-lambda
+      [(mode) (file-stream-buffer-mode p mode)]
+      [() (file-stream-buffer-mode p)]))))
 
 (define (copy-port src dest . dests)
   (unless (input-port? src)

collects/scribblings/reference/port-buffers.scrbl

@@ -73,7 +73,7 @@ accordingly. If the port does not support setting the mode, the
 
 If @racket[mode] is not provided, the current mode is returned, or
 @racket[#f] is returned if the mode cannot be determined. If
-@racket[file-stream-port] is an input port and @racket[mode] is
+@racket[port] is an input port and @racket[mode] is
 @racket['line], the @exnraise[exn:fail:contract].}
 
 @defproc*[([(file-position [port port?]) exact-nonnegative-integer?]

collects/scribblings/reference/port-lib.scrbl

@@ -514,7 +514,7 @@ locations reported by @racket[in].
 If @racket[count-lines!] is supplied, it is called when line counting
 is enabled for the resulting port. The default is @racket[void].}
 
-@defproc[(transplant-output-port [in input-port?]
+@defproc[(transplant-output-port [out output-port?]
                                  [get-location (or/c 
                                                 (->
                                                  (values
@@ -529,6 +529,7 @@ is enabled for the resulting port. The default is @racket[void].}
 
 Like @racket[transplant-input-port], but for output ports.}
 
+
 @defproc[(filter-read-input-port [in input-port?]
                                  [read-wrap (bytes? (or/c exact-nonnegative-integer?
                                                           eof-object?

collects/tests/racket/portlib.rktl

@@ -758,6 +758,42 @@
 
 ;; --------------------------------------------------
 
+(let ([o (open-output-bytes)])
+  (port-count-lines! o)
+  (define o2 (transplant-output-port o
+                                     (lambda ()
+                                       (define-values (l c p) (port-next-location o))
+                                       (values (* 2 l) (* 2 c) (* 2 p)))
+                                     57))
+  (test 0 file-position o)
+  (test 56 file-position o2)
+  (port-count-lines! o2)
+  (test-values '(1 0 1) (lambda () (port-next-location o)))
+  (test-values '(2 0 2) (lambda () (port-next-location o2)))
+  (write-byte 45 o2)
+  (test-values '(1 1 2) (lambda () (port-next-location o)))
+  (test-values '(2 2 4) (lambda () (port-next-location o2)))
+  (test (file-stream-buffer-mode o) file-stream-buffer-mode o2))
+
+(let ([i (open-input-bytes #"x")])
+  (port-count-lines! i)
+  (define i2 (transplant-input-port i
+                                    (lambda ()
+                                      (define-values (l c p) (port-next-location i))
+                                      (values (* 2 l) (* 2 c) (* 2 p)))
+                                    57))
+  (test 0 file-position i)
+  (test 56 file-position i2)
+  (port-count-lines! i2)
+  (test-values '(1 0 1) (lambda () (port-next-location i)))
+  (test-values '(2 0 2) (lambda () (port-next-location i2)))
+  (read-byte i)
+  (test-values '(1 1 2) (lambda () (port-next-location i)))
+  (test-values '(2 2 4) (lambda () (port-next-location i2)))
+  (test (file-stream-buffer-mode i) file-stream-buffer-mode i2))
+
+;; --------------------------------------------------
+
 (let-values ([(in out) (make-pipe)])
   (let ([in2 (dup-input-port in #f)]
         [out2 (dup-output-port out #f)])