Removing helper functions providing Python < 3.3 compatibilityHEAD4.3.0master

Functions used for deriving terminal width are no longer
necessary, as Python 3.3 introduced[0] built in solution.

Remaining helper function `utils.terminal_width` received docstring
explaining return parameters.

Method `_assign_max_widths` of the `TableFormatter` class was refactored
to no longer use the `stdout` argument. Uses of the method were adjusted accordingly.
Method now also has minimal docstring. Minor adjustment was made to inline comments
to more closely reflect functionality of the code.

[0]https://docs.python.org/3.8/library/os.html?highlight=get_terminal_size#os.get_terminal_size

Signed-off-by: Jiri Podivin <jpodivin@redhat.com>
Change-Id: I2898f099227e8c97aef6492c60f2f99038aa1357

1 files changed, 8 insertions, 59 deletions

diff --git a/cliff/utils.py b/cliff/utils.py
index 50f3ab6..3fa02a6 100644
--- a/cliff/utils.py
+++ b/cliff/utils.py
@@ -11,10 +11,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import ctypes
 import os
-import struct
-import sys
 
 # Each edit operation is assigned different cost, such as:
 #  'w' means swap operation, the cost is 0;
@@ -93,63 +90,15 @@ def damerau_levenshtein(s1, s2, cost):
     return row1[-1]
 
 
-def terminal_width(stdout):
-    if hasattr(os, 'get_terminal_size'):
-        # python 3.3 onwards has built-in support for getting terminal size
-        try:
-            return os.get_terminal_size().columns
-        except OSError:
-            return None
+def terminal_width():
+    """Return terminal width in columns
 
-    if sys.platform == 'win32':
-        return _get_terminal_width_windows(stdout)
-    else:
-        return _get_terminal_width_ioctl(stdout)
-
-
-def _get_terminal_width_windows(stdout):
-    STD_INPUT_HANDLE = -10
-    STD_OUTPUT_HANDLE = -11
-    STD_ERROR_HANDLE = -12
-
-    std_to_win_handle = {
-        sys.stdin: STD_INPUT_HANDLE,
-        sys.stdout: STD_OUTPUT_HANDLE,
-        sys.stderr: STD_ERROR_HANDLE}
-
-    std_handle = std_to_win_handle.get(stdout)
-    if not std_handle:
-        return None
-
-    handle = ctypes.windll.kernel32.GetStdHandle(std_handle)
-    csbi = ctypes.create_string_buffer(22)
-
-    res = ctypes.windll.kernel32.GetConsoleScreenBufferInfo(handle, csbi)
-    if res:
-        (size_x, size_y, cur_pos_x, cur_pos_y, attr,
-         left, top, right, bottom, max_size_x, max_size_y) = struct.unpack(
-            "hhhhHhhhhhh", csbi.raw)
-        return size_x
-
-
-def _get_terminal_width_ioctl(stdout):
-    from fcntl import ioctl
-    import termios
+    Uses `os.get_terminal_size` function
 
+    :returns: terminal width
+    :rtype: int or None
+    """
     try:
-        # winsize structure has 4 unsigned short fields
-        winsize = b'\0' * struct.calcsize('hhhh')
-        try:
-            winsize = ioctl(stdout, termios.TIOCGWINSZ, winsize)
-        except IOError:
-            return None
-        except TypeError:
-            # this is raised in unit tests as stdout is sometimes a StringIO
-            return None
-        winsize = struct.unpack('hhhh', winsize)
-        columns = winsize[1]
-        if not columns:
-            return None
-        return columns
-    except IOError:
+        return os.get_terminal_size().columns
+    except OSError:
         return None