[vte] Revert "pty: Use packet mode on the PTY"

[Christian Persch <chpe src gnome org>]

commit 280aa3be8175421d9982bb3b442472a4bef511ea
Author: Christian Persch <chpe gnome org>
Date:   Sun Nov 29 20:57:54 2015 +0100

    Revert "pty: Use packet mode on the PTY"
    
    This reverts commit 512b3d5cf8165ba599e7ba60a0054dcaac9a71f7.

 src/pty.cc         |   26 ------------------------
 src/vte.cc         |   56 ++-------------------------------------------------
 src/vteinternal.hh |    6 +----
 3 files changed, 4 insertions(+), 84 deletions(-)
---
diff --git a/src/pty.cc b/src/pty.cc
index c137eb5..aef4079 100644
--- a/src/pty.cc
+++ b/src/pty.cc
@@ -762,19 +762,6 @@ _vte_pty_getpt(GError **error)
                 return -1;
         }
 
-        /* tty_ioctl(4) -> every read() gives an extra byte at the beginning
-         * notifying us of stop/start (^S/^Q) events. */
-        int one = 1;
-        if (ioctl(fd, TIOCPKT, &one) < 0)
-                int errsv = errno;
-                g_set_error(error, VTE_PTY_ERROR,
-                            VTE_PTY_ERROR_PTY98_FAILED,
-                            "%s failed: %s", "ioctl(TIOCPKT)", g_strerror(errsv));
-                close(fd);
-                errno = errsv;
-                return -1;
-        }
-
        return fd;
 }
 
@@ -897,19 +884,6 @@ _vte_pty_open_bsd(VtePty *pty,
                return FALSE;
        }
 
-        /* tty_ioctl(4) -> every read() gives an extra byte at the beginning
-         * notifying us of stop/start (^S/^Q) events. */
-        int one = 1;
-        if (ioctl(parentfd, TIOCPKT, &one) < 0) {
-                int errsv = errno;
-                g_set_error(error, G_IO_ERROR, g_io_error_from_errno(errsv),
-                            "%s failed: %s", "ioctl(TIOCPKT)", g_strerror(errsv));
-                close(parentfd);
-                close(childfd);
-                errno = errsv;
-                return FALSE;
-        }
-
        priv->pty_fd = parentfd;
        priv->child_setup_data.mode = TTY_OPEN_BY_FD;
        priv->child_setup_data.tty.fd = childfd;
diff --git a/src/vte.cc b/src/vte.cc
index eb6702e..a7c91a1 100644
--- a/src/vte.cc
+++ b/src/vte.cc
@@ -53,12 +53,6 @@
 
 #include <new> /* placement new */
 
-/* Some sanity checks */
-/* FIXMEchpe: move this to there when splitting _vte_incoming_chunk into its own file */
-static_assert(sizeof(struct _vte_incoming_chunk) <= VTE_INPUT_CHUNK_SIZE, "_vte_incoming_chunk too large");
-static_assert(offsetof(struct _vte_incoming_chunk, data) == offsetof(struct _vte_incoming_chunk, 
dataminusone) + 1, "_vte_incoming_chunk layout wrong");
-
-
 #ifndef HAVE_ROUND
 static inline double round(double x) {
        if(x - floor(x) < 0.5) {
@@ -3426,7 +3420,7 @@ VteTerminalPrivate::connect_pty_read()
                m_pty_input_source =
                        g_io_add_watch_full(m_pty_channel,
                                            VTE_CHILD_INPUT_PRIORITY,
-                                           (GIOCondition)(G_IO_IN | G_IO_PRI | G_IO_HUP),
+                                           (GIOCondition)(G_IO_IN | G_IO_HUP),
                                            (GIOFunc) vte_terminal_io_read,
                                            m_terminal,
                                            (GDestroyNotify) mark_input_source_invalid);
@@ -3489,20 +3483,6 @@ VteTerminalPrivate::disconnect_pty_write()
        }
 }
 
-void
-VteTerminalPrivate::pty_termios_changed()
-{
-        _vte_debug_print(VTE_DEBUG_IO, "Termios changed\n");
-}
-
-void
-VteTerminalPrivate::pty_scroll_lock_changed(bool locked)
-{
-        _vte_debug_print(VTE_DEBUG_IO, "Output %s (^%c)\n",
-                         locked ? "stopped" : "started",
-                         locked ? 'Q' : 'S');
-}
-
 /*
  * VteTerminalPrivate::watch_child:
  * @child_pid: a #GPid
@@ -4114,7 +4094,7 @@ vte_terminal_io_read(GIOChannel *channel,
        eof = condition & G_IO_HUP;
 
        /* Read some data in from this channel. */
-       if (condition & (G_IO_IN | G_IO_PRI)) {
+       if (condition & G_IO_IN) {
                struct _vte_incoming_chunk *chunk, *chunks = NULL;
                const int fd = g_io_channel_unix_get_fd (channel);
                guchar *bp;
@@ -4149,16 +4129,7 @@ vte_terminal_io_read(GIOChannel *channel,
                        bp = chunk->data + chunk->len;
                        len = 0;
                        do {
-                                /* We'd like to read (fd, bp, rem); but due to TIOCPKT mode
-                                 * there's an extra input byte returned at the beginning.
-                                 * We need to see what that byte is, but otherwise drop it
-                                 * and write continuously to chunk->data.
-                                 */
-                                char pkt_header;
-                                char save = bp[-1];
-                                int ret = read (fd, bp - 1, rem + 1);
-                                pkt_header = bp[-1];
-                                bp[-1] = save;
+                               int ret = read (fd, bp, rem);
                                switch (ret){
                                        case -1:
                                                err = errno;
@@ -4167,27 +4138,6 @@ vte_terminal_io_read(GIOChannel *channel,
                                                eof = TRUE;
                                                goto out;
                                        default:
-                                                ret--;
-
-                                                if (pkt_header & TIOCPKT_IOCTL) {
-                                                        /* We'd like to always be informed when the termios 
change,
-                                                         * so we can e.g. detect when no-echo is en/disabled 
and
-                                                         * change the cursor/input method/etc., but 
unfortunately
-                                                         * the kernel only sends this flag when (old or new) 
'local flags'
-                                                         * include EXTPROC, which is not used often, and due 
to its side
-                                                         * effects, cannot be enabled by vte by default.
-                                                         *
-                                                         * FIXME: improve the kernel! see discussion in bug 
755371
-                                                         * starting at comment 12
-                                                         */
-                                                        terminal->pvt->pty_termios_changed();
-                                                }
-                                                if (pkt_header & TIOCPKT_STOP) {
-                                                        terminal->pvt->pty_scroll_lock_changed(true);
-                                                } else if (pkt_header & TIOCPKT_START) {
-                                                        terminal->pvt->pty_scroll_lock_changed(false);
-                                                }
-
                                                bp += ret;
                                                rem -= ret;
                                                len += ret;
diff --git a/src/vteinternal.hh b/src/vteinternal.hh
index 8448ec2..a37382c 100644
--- a/src/vteinternal.hh
+++ b/src/vteinternal.hh
@@ -125,8 +125,7 @@ typedef struct _vte_incoming_chunk _vte_incoming_chunk_t;
 struct _vte_incoming_chunk{
         _vte_incoming_chunk_t *next;
         guint len;
-        guchar dataminusone;    /* Hack: Keep it right before data, so that data[-1] is valid and usable */
-        guchar data[VTE_INPUT_CHUNK_SIZE - 2 * sizeof(void *) - 1];
+        guchar data[VTE_INPUT_CHUNK_SIZE - 2 * sizeof(void *)];
 };
 
 typedef struct _VteScreen VteScreen;
@@ -513,9 +512,6 @@ public:
         void connect_pty_write();
         void disconnect_pty_write();
 
-        void pty_termios_changed();
-        void pty_scroll_lock_changed(bool locked);
-
         void watch_child (GPid child_pid);
         bool spawn_sync(VtePtyFlags pty_flags,
                         const char *working_directory,