Make tcvt aware of the OSC sequences

Ansi is vague about the meaning of the OSC sequences (i.e.,
the control sequences starting with <esc> ]): the interpretation is
up to the operating system. Nevertheless, some programs send these
sequences, most prominently the one to set the terminal title (OSC 0;).
So make tcvt aware of those sequences and pass them through.

Signed-off-by: Helmut Grohne <helmut@subdivi.de>

1 files changed, 24 insertions, 0 deletions

diff --git a/tcvt.py b/tcvt.py
index 55084b8..0e1a528 100755
--- a/tcvt.py
+++ b/tcvt.py
@@ -562,6 +562,8 @@ class Terminal:
     def feed_esc(self, char):
         if char == ord(b'['):
             self.mode = (self.feed_esc_opbr,)
+        elif char == ord(b']'):
+            self.mode = (self.feed_esc_clbr, bytearray())
         else:
             raise ValueError("feed esc %r" % char)
 
@@ -660,6 +662,28 @@ class Terminal:
         else:
             raise ValueError("feed esc [ %r %r" % (prev, char))
 
+    def feed_esc_clbr(self, char, prev):
+        self.feed_reset()
+        if char == 7:
+            # Bell character, end of control sequence; pass it through
+            # if one of those that do not interfere with the other curses.
+            if not prev.startswith((b"0;", b"1;", b"2;")):
+                raise ValueError("dropped osc sequence: esc ] %r bel"
+                                 % (prev,))
+            self.refresh()
+            if sys.version_info.major == 2:
+                stdout = sys.stdout
+            else:
+                stdout = sys.stdout.buffer
+            stdout.write(bytearray(b"\x1b]") + prev + bytearray(b"\x07"))
+            stdout.flush()
+
+        elif 8 <= char <= 13 or 32 <= char <= 126:
+            self.mode = (self.feed_esc_clbr, prev + bytearray((char,)))
+        else:
+            raise ValueError("feed esc ] %r %r" % (prev, char))
+
+
 symbolic_keymapping = {
     ord(b"\n"): "cr",
     curses.KEY_LEFT: "kcub1",