Revert "Handle CRLF and Unicode line endings in read-line"

This reverts commit 0f983e3db0.

After discussing with Mike we are going to punt the read-line changes
for now.  Open the port in O_TEXT mode if you want to chomp the CR in
CFLF sequences.

NEWS

@@ -166,12 +166,6 @@ See the newly reorganized "Foreign Function Interface", for details.
 These new interfaces replace `dynamic-link', `dynamic-pointer' and
 similar, which will eventually be deprecated.
 
-** `read-line'
-
-This now accepts return + newline and the Unicode line separator and
-paragraph separator as line separators, as well as the newline and <eof>
-line separators it handled before.
-
 ** `read-syntax'
 
 See "Annotated Scheme Read" in the manual.

doc/ref/api-io.texi

@@ -755,10 +755,8 @@ a specified set of characters.
 
 @deffn {Scheme Procedure} read-line [port] [handle-delim]
 Return a line of text from @var{port} if specified, otherwise from the
-value returned by @code{(current-input-port)}.  Under Unix, a line of
+value returned by @code{(current-input-port)}.  Under Unix, a line of text
-text is terminated by the first end-of-line character or by end-of-file.
+is terminated by the first end-of-line character or by end-of-file.
-The end-of-line characters handled are newline, carriage return plus
-newline, or the Unicode line or paragraph separators.
 
 If @var{handle-delim} is specified, it should be one of the following
 symbols:
@@ -773,9 +771,7 @@ Append the terminating delimiter (if any) to the returned string.
 Push the terminating delimiter (if any) back on to the port.
 @item split
 Return a pair containing the string read from the port and the
-terminating delimiter or end-of-file object.  The delimiter will either
+terminating delimiter or end-of-file object.
-be a single character for newline or the Unicode line or paragraph
-separators, or it will be the string @code{"\r\n"}.
 @end table
 @end deffn
 

libguile/rdelim.c

@@ -112,11 +112,10 @@ SCM_DEFINE (scm_read_delimited_x, "%read-delimited!", 3, 3, 0,
 
 SCM_DEFINE (scm_read_line, "%read-line", 0, 1, 0, 
             (SCM port),
-	    "Read a line from @var{port}, allocating storage as necessary.\n"
+	    "Read a newline-terminated line from @var{port}, allocating storage as\n"
-	    "The terminator (if any) is removed from the string,\n"
+	    "necessary.  The newline terminator (if any) is removed from the string,\n"
 	    "and a pair consisting of the line and its delimiter is returned.  The\n"
-	    "delimiter may be either a newline, return + newline, the Unicode\n"
+	    "delimiter may be either a newline or the @var{eof-object}; if\n"
-            "line or paragraph separators, or the @var{eof-object}; if\n"
 	    "@code{%read-line} is called at the end of file, it returns the pair\n"
 	    "@code{(#<eof> . #<eof>)}.")
 #define FUNC_NAME s_scm_read_line
@@ -128,7 +127,6 @@ SCM_DEFINE (scm_read_line, "%read-line", 0, 1, 0,
   SCM line, strings, result;
   scm_t_wchar buf[LINE_BUFFER_SIZE], delim;
   size_t index;
-  int cr = 0;
 
   if (SCM_UNBNDP (port))
     port = scm_current_input_port ();
@@ -154,24 +152,12 @@ SCM_DEFINE (scm_read_line, "%read-line", 0, 1, 0,
 	  buf[index] = scm_getc (port);
 	  switch (buf[index])
 	    {
+	    case EOF:
 	    case '\n':
 	      delim = buf[index];
 	      break;
 
-            case EOF:
-            case 0x2028:        /* U+2028 LINE SEPARATOR */
-            case 0x2029:        /* U+2029 PARAGRAPH SEPARATOR */
-              cr = 0;
-              delim = buf[index];
-              break;
-
-            case '\r':
-              cr = 1;
-              index ++;
-              break;
-
 	    default:
-              cr = 0;
 	      index++;
 	    }
 	}
@@ -179,33 +165,20 @@ SCM_DEFINE (scm_read_line, "%read-line", 0, 1, 0,
   while (delim == 0);
 
   if (SCM_LIKELY (scm_is_false (strings)))
-    {
     /* The fast path.  */
-      if (cr)
-        line = scm_from_utf32_stringn (buf, index - 1);
-      else
     line = scm_from_utf32_stringn (buf, index);
-    }
   else
     {
       /* Aggregate the intermediary results.  */
-      if (cr)
-        strings = scm_cons (scm_from_utf32_stringn (buf, index - 1), strings);
-      else
       strings = scm_cons (scm_from_utf32_stringn (buf, index), strings);
       line = scm_string_concatenate (scm_reverse (strings));
     }
 
   if (delim == EOF && scm_i_string_length (line) == 0)
     result = scm_cons (SCM_EOF_VAL, SCM_EOF_VAL);
-  else
-    {
-      if (cr)
-        result = scm_cons (line, scm_from_latin1_string("\r\n"));
   else
     result = scm_cons (line,
 		       delim == EOF ? SCM_EOF_VAL : SCM_MAKE_CHAR (delim));
-    }
 
   return result;
 #undef LINE_BUFFER_SIZE

module/ice-9/suspendable-ports.scm

@@ -1,5 +1,5 @@
 ;;; Ports, implemented in Scheme
-;;; Copyright (C) 2016, 2018, 2021 Free Software Foundation, Inc.
+;;; Copyright (C) 2016, 2019 Free Software Foundation, Inc.
 ;;;
 ;;; This library is free software: you can redistribute it and/or modify
 ;;; it under the terms of the GNU Lesser General Public License as
@@ -689,81 +689,10 @@
 
 (define* (read-line #:optional (port (current-input-port))
                     (handle-delim 'trim))
-  (let* ((line/delim	(%read-line port))
+  (read-delimited "\n" port handle-delim))
-	 (line		(car line/delim))
-	 (delim		(cdr line/delim)))
-    (case handle-delim
-      ((trim) line)
-      ((split) line/delim)
-      ((concat) (if (and (string? line) (char? delim))
-		    (string-append line (string delim))
-		    line))
-      ((peek) (if (char? delim)
-		  (unread-char delim port))
-	      line)
-      (else
-       (error "unexpected handle-delim value: " handle-delim)))))
 
 (define* (%read-line port)
-  (let ((LINE_BUFFER_SIZE 256))
+  (read-line port 'split))
-    (let ((strings #f)
-          (result #f)
-          (buf (make-string LINE_BUFFER_SIZE #\nul))
-          (delim #f)
-          (index 0)
-          (cr #f)
-          (go #t))
-      (cond
-       ((not (input-port? port))
-        (error "Not an input port." port))
-       (else
-        (while go
-               (cond
-                ((>= index LINE_BUFFER_SIZE)
-                 (set! strings (cons (substring buf 0 index)
-                                     (or strings '())))
-                 (set! index 0))
-                (else
-                 (let ((c (read-char port)))
-                   (cond
-                    ((or (eof-object? c)
-                         (char=? c #\x2028)  ; U+2028 LINE SEPARATOR
-                         (char=? c #\x2029)) ; U+2029 PARAGRAPH SEPARATOR
-                     (set! cr #f)
-                     (set! delim c))
-                    ((char=? c #\newline)
-                     (set! delim c))
-                    ((char=? c #\return)
-                     (set! cr #t)
-                     (string-set! buf index c)
-                     (set! index (1+ index)))
-                    (else
-                     (set! cr #f)
-                     (string-set! buf index c)
-                     (set! index (1+ index)))))))
-
-               (if (or (eof-object? delim)
-                       (char? delim))
-                   (set! go #f)))
-      (let ((line (if (not strings)
-                      ;; A short string.
-                      (if cr
-                          (substring buf 0 (1- index))
-                          (substring buf 0 index))
-                      ;; Else, aggregate the intermediary results.
-                      (begin
-                        (if cr
-                            (set! strings (cons (substring buf 0 (1- index)) strings))
-                            (set! strings (cons (substring buf 0 index) strings)))
-                        (apply string-append (reverse strings))))))
-
-        (if (and (eof-object? delim)
-                 (zero? (string-length line)))
-            (cons the-eof-object the-eof-object)
-            ;; Else
-            (if cr
-                (cons line "\r\n")
-                (cons line delim)))))))))
 
 (define* (put-string port str #:optional (start 0)
                      (count (- (string-length str) start)))

module/web/http.scm

@@ -157,12 +157,13 @@ The default writer will call ‘put-string’."
 Raise a 'bad-header' exception if the line does not end in CRLF or LF,
 or if EOF is reached."
   (match (%read-line port)
-    (((? string? line) . "\r\n")
-     line)
     (((? string? line) . #\newline)
-     ;; We are more tolerant than the RFC in that we tolerate LF-only
+     ;; '%read-line' does not consider #\return a delimiter; so if it's
-     ;; endings.
+     ;; there, remove it.  We are more tolerant than the RFC in that we
-     line)
+     ;; tolerate LF-only endings.
+     (if (string-suffix? "\r" line)
+         (string-drop-right line 1)
+         line))
     ((line . _)                                ;EOF or missing delimiter
      (bad-header 'read-header-line line))))
 
@@ -183,7 +184,8 @@ was known but the value was invalid.
 Returns the end-of-file object for both values if the end of the message
 body was reached (i.e., a blank line)."
   (let ((line (read-header-line port)))
-    (if (string-null? line)
+    (if (or (string-null? line)
+            (string=? line "\r"))
         (values *eof* *eof*)
         (let* ((delim (or (string-index line #\:)
                           (bad-header '%read line)))

test-suite/tests/rdelim.test

@@ -1,7 +1,7 @@
 ;;;; rdelim.test --- Delimited I/O.      -*- mode: scheme; coding: utf-8; -*-
 ;;;; Ludovic Courtès <ludo@gnu.org>
 ;;;;
-;;;; 	Copyright (C) 2011, 2013, 2014, 2021 Free Software Foundation, Inc.
+;;;; 	Copyright (C) 2011, 2013, 2014 Free Software Foundation, Inc.
 ;;;;
 ;;;; This library is free software; you can redistribute it and/or
 ;;;; modify it under the terms of the GNU Lesser General Public
@@ -62,46 +62,6 @@
                          (read-line p 'split)))
            (eof-object? (read-line p)))))
 
-  (pass-if "two lines, split, CRLF"
-    (let* ((s "foo\r\nbar\r\n")
-           (p (open-input-string s)))
-      (and (equal? '(("foo" . "\r\n")
-                     ("bar" . "\r\n"))
-                   (list (read-line p 'split)
-                         (read-line p 'split)))
-           (eof-object? (read-line p)))))
-
-  (pass-if "two long lines, split, CRLF"
-    ;; Must be longer than 256 codepoints
-    (let* ((text0 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
-           (text1 (string-append text0 text0 text0 text0 text0))
-           (text2 (string-append text1 "\r\n" text1 "\r\n")))
-      (let* ((s text2)
-             (p (open-input-string s)))
-        (and (equal? `((,text1 . "\r\n")
-                       (,text1 . "\r\n"))
-                     (list (read-line p 'split)
-                           (read-line p 'split)))
-             (eof-object? (read-line p))))))
-
-  (pass-if "two lines, split, LS"
-    (let* ((s "foo\u2028bar\u2028")
-           (p (open-input-string s)))
-      (and (equal? '(("foo" . #\x2028)
-                     ("bar" . #\x2028))
-                   (list (read-line p 'split)
-                         (read-line p 'split)))
-           (eof-object? (read-line p)))))
-
-  (pass-if "two lines, split, PS"
-    (let* ((s "foo\u2029bar\u2029")
-           (p (open-input-string s)))
-      (and (equal? '(("foo" . #\x2029)
-                     ("bar" . #\x2029))
-                   (list (read-line p 'split)
-                         (read-line p 'split)))
-           (eof-object? (read-line p)))))
-
   (pass-if "two Greek lines, trim"
     (let* ((s "λαμβδα\nμυ\n")
            (p (open-input-string s)))