[chirp_devel] [PATCH] [RFC] Natively support null-terminated strings in Browser

[Tom Hayward]

# HG changeset patch
# User Tom Hayward <tom at tomh.us>
# Date 1490595310 25200
#      Sun Mar 26 23:15:10 2017 -0700
# Node ID 50462c735ef1eee2d3bb2bb2c4d0f49fa0a4f2ef
# Parent  c558e223d37835907823f1804ade6a8bcf0b4594
[RFC] Natively support null-terminated strings in Browser.

When a bitwise char array that contains a null character is requsted in the
Browser, there is an error:

Traceback (most recent call last):
  File "/home/tom/src/chirp.hg/chirp/ui/radiobrowser.py", line 313, in _tree_click
    e = CharArrayEditor(item)
  File "/home/tom/src/chirp.hg/chirp/ui/radiobrowser.py", line 123, in __init__
    self._build_ui()
  File "/home/tom/src/chirp.hg/chirp/ui/radiobrowser.py", line 206, in _build_ui
    ent.set_text(str(self._element))
TypeError: Gtk.Entry.set_text() argument 1 must be string without null bytes, not str

This errors results in the char array contents not being displayed at all. All
we get is the attribute name.

Radios commonly store strings shorter than the maximum length with null
characters filling the remaining space. This is so common that I think the
browser should be able to display it.

This patch strips the null characters off the char array so that Gtk doesn't
freak out. This results in the string being displayed correctly.

The side effect is that the null characters are discarded on change. If the
field is edited in the browser, Chirp fills the empty chars with spaces, not
null characters like were there originally. Visually there is no difference,
but the stored data are different.

I don't think this will break anything. Can anyone think of a reason this would
be a problem?

Is this complete? Should \xFF be stripped as well? They're visually unpleasing,
but don't break Gtk like \x00 does.

Is there a better way to handle this? Should we use repr() to show the
unprintable null characters, then interpret escape characters on set? This
is awkward because the Entry has a max length defined to the array size, and
could have false positives when people use \ in their labels.)

diff -r c558e223d378 -r 50462c735ef1 chirp/ui/radiobrowser.py
--- a/chirp/ui/radiobrowser.py	Sun Mar 26 22:23:11 2017 -0700
+++ b/chirp/ui/radiobrowser.py	Sun Mar 26 23:15:10 2017 -0700
@@ -202,7 +202,7 @@
 
     def _build_ui(self):
         ent = FixedEntry(len(self._element))
-        ent.set_text(str(self._element))
+        ent.set_text(str(self._element).rstrip("\x00"))
         ent.connect('changed', self._changed)
         ent.show()
         self.pack_start(ent, 1, 1, 1)