bug#20978: [PATCH 2/7] ; Remove ADAPTIVE_READ_BUFFERING ifdef

[Ian Kelling]

* src/process.c (make-process, make-pipe-process, deactivate_process)
(wait_reading_process_output, read_process_output, send_process)
(init_process_emacs): ifdef ADAPTIVE_READ_BUFFERING was originally
added in case there was an operating system in which it was not
useful. That was 11 years ago and it hasn't happened. Make development
easier by not considering the effect of changes on a theoretical OS
where this is disabled.

diff --git a/src/process.c b/src/process.c
index 191f617..1541de2 100644
--- a/src/process.c
+++ b/src/process.c
@@ -224,11 +224,6 @@ static EMACS_INT update_tick;
 # define HAVE_SEQPACKET
 #endif

-#if !defined (ADAPTIVE_READ_BUFFERING) && !defined (NO_ADAPTIVE_READ_BUFFERING)
-#define ADAPTIVE_READ_BUFFERING
-#endif
-
-#ifdef ADAPTIVE_READ_BUFFERING
 #define READ_OUTPUT_DELAY_INCREMENT (TIMESPEC_RESOLUTION / 100)
 #define READ_OUTPUT_DELAY_MAX       (READ_OUTPUT_DELAY_INCREMENT * 5)
 #define READ_OUTPUT_DELAY_MAX_MAX   (READ_OUTPUT_DELAY_INCREMENT * 7)
@@ -242,10 +237,6 @@ static int process_output_delay_count;

 static bool process_output_skip;

-#else
-#define process_output_delay_count 0
-#endif
-
 static void create_process (Lisp_Object, char **, Lisp_Object);
 #ifdef USABLE_SIGIO
 static bool keyboard_bit_set (fd_set *);
@@ -1517,11 +1508,9 @@ usage: (make-process &rest ARGS)  */)
   pset_gnutls_cred_type (XPROCESS (proc), Qnil);
 #endif

-#ifdef ADAPTIVE_READ_BUFFERING
   XPROCESS (proc)->adaptive_read_buffering
     = (NILP (Vprocess_adaptive_read_buffering) ? 0
        : EQ (Vprocess_adaptive_read_buffering, Qt) ? 1 : 2);
-#endif

   /* Make the process marker point into the process buffer (if any).  */
   if (BUFFERP (buffer))
@@ -2184,11 +2173,9 @@ usage:  (make-pipe-process &rest ARGS)  */)
       FD_SET (inchannel, &input_wait_mask);
       FD_SET (inchannel, &non_keyboard_wait_mask);
     }
-#ifdef ADAPTIVE_READ_BUFFERING
   p->adaptive_read_buffering
     = (NILP (Vprocess_adaptive_read_buffering) ? 0
        : EQ (Vprocess_adaptive_read_buffering, Qt) ? 1 : 2);
-#endif

   /* Make the process marker point into the process buffer (if any).  */
   if (BUFFERP (buffer))
@@ -4183,7 +4170,6 @@ deactivate_process (Lisp_Object proc)
   emacs_gnutls_deinit (proc);
 #endif /* HAVE_GNUTLS */

-#ifdef ADAPTIVE_READ_BUFFERING
   if (p->read_output_delay > 0)
     {
       if (--process_output_delay_count < 0)
@@ -4191,7 +4177,6 @@ deactivate_process (Lisp_Object proc)
       p->read_output_delay = 0;
       p->read_output_skip = 0;
     }
-#endif

   /* Beware SIGCHLD hereabouts.  */

@@ -4876,7 +4861,6 @@ wait_reading_process_output (intmax_t time_limit, int 
nsecs, int read_kbd,
       else
        {

-#ifdef ADAPTIVE_READ_BUFFERING
          /* Set the timeout for adaptive read buffering if any
             process has non-zero read_output_skip and non-zero
             read_output_delay, and we are not reading output for a
@@ -4908,7 +4892,6 @@ wait_reading_process_output (intmax_t time_limit, int 
nsecs, int read_kbd,
              timeout = make_timespec (0, nsecs);
              process_output_skip = 0;
            }
-#endif

 #if defined (HAVE_NS)
           nfds = ns_select
@@ -5345,7 +5328,6 @@ read_process_output (Lisp_Object proc, int channel)
 #endif
        nbytes = emacs_read (channel, chars + carryover + buffered,
                             readmax - buffered);
-#ifdef ADAPTIVE_READ_BUFFERING
       if (nbytes > 0 && p->adaptive_read_buffering)
        {
          int delay = p->read_output_delay;
@@ -5371,7 +5353,6 @@ read_process_output (Lisp_Object proc, int channel)
              process_output_skip = 1;
            }
        }
-#endif
       nbytes += buffered;
       nbytes += buffered && nbytes <= 0;
     }
@@ -5840,7 +5821,6 @@ send_process (Lisp_Object proc, const char *buf, 
ptrdiff_t len,
 #endif
                written = emacs_write_sig (outfd, cur_buf, cur_len);
              rv = (written ? 0 : -1);
-#ifdef ADAPTIVE_READ_BUFFERING
              if (p->read_output_delay > 0
                  && p->adaptive_read_buffering == 1)
                {
@@ -5848,7 +5828,6 @@ send_process (Lisp_Object proc, const char *buf, 
ptrdiff_t len,
                  process_output_delay_count--;
                  p->read_output_skip = 0;
                }
-#endif
            }

          if (rv < 0)
@@ -7470,10 +7449,8 @@ init_process_emacs (void)
   num_pending_connects = 0;
 #endif

-#ifdef ADAPTIVE_READ_BUFFERING
   process_output_delay_count = 0;
   process_output_skip = 0;
-#endif

   /* Don't do this, it caused infinite select loops.  The display
      method should call add_keyboard_wait_descriptor on stdin if it
@@ -7638,7 +7615,6 @@ then a pipe is used in any case.
 The value takes effect when `start-process' is called.  */);
   Vprocess_connection_type = Qt;

-#ifdef ADAPTIVE_READ_BUFFERING
   DEFVAR_LISP ("process-adaptive-read-buffering", 
Vprocess_adaptive_read_buffering,
               doc: /* If non-nil, improve receive buffering by delaying after 
short reads.
 On some systems, when Emacs reads the output from a subprocess, the output data
@@ -7650,7 +7626,6 @@ If the value is t, the delay is reset after each write to 
the process; any other
 non-nil value means that the delay is not reset on write.
 The variable takes effect when `start-process' is called.  */);
   Vprocess_adaptive_read_buffering = Qt;
-#endif

   defsubr (&Sprocessp);
   defsubr (&Sget_process);
--
2.4.5