[Python-checkins] cpython (3.5): Issue #23735: Add SIGWINCH handler for Readline 6.3+ support, by Eric Price

[martin.panter]

https://hg.python.org/cpython/rev/b29edd0108ee
changeset:   100840:b29edd0108ee
branch:      3.5
parent:      100836:f5247195238f
user:        Martin Panter <vadmium+py at gmail.com>
date:        Sun Apr 03 02:54:58 2016 +0000
summary:
  Issue #23735: Add SIGWINCH handler for Readline 6.3+ support, by Eric Price

files:
  Misc/ACKS          |   1 +
  Misc/NEWS          |   3 ++
  Modules/readline.c |  31 +++++++++++++++++++++++
  configure          |  44 ++++++++++++++++++++++++++++++++++
  configure.ac       |   5 +++
  pyconfig.h.in      |   3 ++
  6 files changed, 87 insertions(+), 0 deletions(-)


diff --git a/Misc/ACKS b/Misc/ACKS
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1155,6 +1155,7 @@
 Amrit Prem
 Paul Prescod
 Donovan Preston
+Eric Price
 Paul Price
 Iuliia Proskurnia
 Dorian Pula
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -99,6 +99,9 @@
 Library
 -------
 
+- Issue #23735: Handle terminal resizing with Readline 6.3+ by installing our
+  own SIGWINCH handler.  Patch by Eric Price.
+
 - Issue #26586: In http.server, respond with "413 Request header fields too
   large" if there are too many header fields to parse, rather than killing
   the connection and raising an unhandled exception.  Patch by Xiang Zhang.
diff --git a/Modules/readline.c b/Modules/readline.c
--- a/Modules/readline.c
+++ b/Modules/readline.c
@@ -928,6 +928,26 @@
 
 #endif
 
+#ifdef HAVE_RL_RESIZE_TERMINAL
+static volatile sig_atomic_t sigwinch_received;
+static sighandler_t sigwinch_ohandler;
+
+static void
+readline_sigwinch_handler(int signum)
+{
+    sigwinch_received = 1;
+    if (sigwinch_ohandler &&
+            sigwinch_ohandler != SIG_IGN && sigwinch_ohandler != SIG_DFL)
+        sigwinch_ohandler(signum);
+
+#ifndef HAVE_SIGACTION
+    /* If the handler was installed with signal() rather than sigaction(),
+    we need to reinstall it. */
+    PyOS_setsig(SIGWINCH, readline_sigwinch_handler);
+#endif
+}
+#endif
+
 /* C function to call the Python completer. */
 
 static char *
@@ -1033,6 +1053,10 @@
     /* Bind both ESC-TAB and ESC-ESC to the completion function */
     rl_bind_key_in_map ('\t', rl_complete, emacs_meta_keymap);
     rl_bind_key_in_map ('\033', rl_complete, emacs_meta_keymap);
+#ifdef HAVE_RL_RESIZE_TERMINAL
+    /* Set up signal handler for window resize */
+    sigwinch_ohandler = PyOS_setsig(SIGWINCH, readline_sigwinch_handler);
+#endif
     /* Set our hook functions */
     rl_startup_hook = on_startup_hook;
 #ifdef HAVE_RL_PRE_INPUT_HOOK
@@ -1118,6 +1142,13 @@
             struct timeval *timeoutp = NULL;
             if (PyOS_InputHook)
                 timeoutp = &timeout;
+#ifdef HAVE_RL_RESIZE_TERMINAL
+            /* Update readline's view of the window size after SIGWINCH */
+            if (sigwinch_received) {
+                sigwinch_received = 0;
+                rl_resize_terminal();
+            }
+#endif
             FD_SET(fileno(rl_instream), &selectset);
             /* select resets selectset if no input was available */
             has_input = select(fileno(rl_instream) + 1, &selectset,
diff --git a/configure b/configure
--- a/configure
+++ b/configure
@@ -14929,6 +14929,50 @@
 fi
 
 
+# also in 4.0, but not in editline
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_resize_terminal in -lreadline" >&5
+$as_echo_n "checking for rl_resize_terminal in -lreadline... " >&6; }
+if ${ac_cv_lib_readline_rl_resize_terminal+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lreadline $READLINE_LIBS $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char rl_resize_terminal ();
+int
+main ()
+{
+return rl_resize_terminal ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_readline_rl_resize_terminal=yes
+else
+  ac_cv_lib_readline_rl_resize_terminal=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_readline_rl_resize_terminal" >&5
+$as_echo "$ac_cv_lib_readline_rl_resize_terminal" >&6; }
+if test "x$ac_cv_lib_readline_rl_resize_terminal" = xyes; then :
+
+$as_echo "#define HAVE_RL_RESIZE_TERMINAL 1" >>confdefs.h
+
+fi
+
+
 # check for readline 4.2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for rl_completion_matches in -lreadline" >&5
 $as_echo_n "checking for rl_completion_matches in -lreadline... " >&6; }
diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -4527,6 +4527,11 @@
 	AC_DEFINE(HAVE_RL_COMPLETION_DISPLAY_MATCHES_HOOK, 1,
         [Define if you have readline 4.0]), ,$READLINE_LIBS)
 
+# also in 4.0, but not in editline
+AC_CHECK_LIB(readline, rl_resize_terminal,
+	AC_DEFINE(HAVE_RL_RESIZE_TERMINAL, 1,
+        [Define if you have readline 4.0]), ,$READLINE_LIBS)
+
 # check for readline 4.2
 AC_CHECK_LIB(readline, rl_completion_matches,
 	AC_DEFINE(HAVE_RL_COMPLETION_MATCHES, 1,
diff --git a/pyconfig.h.in b/pyconfig.h.in
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -735,6 +735,9 @@
 /* Define if you have readline 4.0 */
 #undef HAVE_RL_PRE_INPUT_HOOK
 
+/* Define if you have readline 4.0 */
+#undef HAVE_RL_RESIZE_TERMINAL
+
 /* Define to 1 if you have the `round' function. */
 #undef HAVE_ROUND
 

-- 
Repository URL: https://hg.python.org/cpython