[PATCH] factor: reinstate immediate output with interactive use

[Pádraig Brady]

* src/factor.c (lbuf_putc): Only buffer more than a line
when not using the tool interactively.
* NEWS: Mention the bug fix.
Fixes http://pad.lv/1620139
---
 NEWS         | 3 +++
 src/factor.c | 8 +++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index 34a969e..a699010 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,9 @@ GNU coreutils NEWS                                    -*- 
outline -*-
   System V style platforms where this information is available only
   in the global variable 'tzname'. [bug introduced in coreutils-8.24]
 
+  factor again outputs immediately when numbers are input interactively.
+  [bug introduced in coreutils-8.24]
+
   nl now resets numbering for each page section rather than just for each page.
   [This bug was present in "the beginning".]
 
diff --git a/src/factor.c b/src/factor.c
index 8fee759..c648a1d 100644
--- a/src/factor.c
+++ b/src/factor.c
@@ -2379,7 +2379,13 @@ lbuf_putc (char c)
     {
       size_t buffered = lbuf.end - lbuf.buf;
 
-      if (buffered >= FACTOR_PIPE_BUF)
+      /* Provide immediate output for interactive input.  */
+      static int line_buffered = -1;
+      if (line_buffered == -1)
+        line_buffered = isatty(STDIN_FILENO);
+      if (line_buffered)
+        lbuf_flush ();
+      else if (buffered >= FACTOR_PIPE_BUF)
         {
           /* Write output in <= PIPE_BUF chunks
              so consumers can read atomically.  */
-- 
2.5.5