Improved terminal functions.

doc/changelog.txt

@@ -10,6 +10,7 @@ Changes:
 - comics: Removed the twisted and zope dependencies by adding
   an internal plugin search mechanism.
 - testing: Refactored the test comic routine in proper unit tests.
+- cmdline: Improved terminal feature detection.
 
 Fixes:
 - comics: Adjusted Xkcd href values.

dosage

@@ -22,7 +22,7 @@ import traceback
 
 from dosagelib import events, scraper
 from dosagelib.output import out
-from dosagelib.util import getWindowSize, internal_error
+from dosagelib.util import is_tty, get_columns, internal_error
 from dosagelib.configuration import App, Freeware, Copyright
 
 def setupOptions():
@@ -38,14 +38,7 @@ def setupOptions():
     parser.add_option('-m', '--module-help', action='store_true', dest='modhelp', help='display help for comic modules')
     parser.add_option('-t', '--timestamps', action='store_true', dest='timestamps', default=False, help='print timestamps for all output at any info level')
     parser.add_option('-o', '--output', action='store', dest='output', choices=events.getHandlers(), help='output formatting for downloaded comics')
-    try:
-        getWindowSize()
-    except NotImplementedError:
-        progress = False
-    else:
-        progress = True
-
-    if progress:
+    if is_tty(sys.stdout):
         parser.add_option('-p', '--progress', action='store_true', dest='progress', default=False, help='display progress bar while downloading comics')
     return parser
 
@@ -131,10 +124,7 @@ class Dosage(object):
         print '\n'.join(scraper.get_name() for scraper in scrapers)
 
     def doColumnList(self, scrapers):
-        try:
-            screenWidth = getWindowSize()
-        except NotImplementedError:
-            screenWidth = 80
+        screenWidth = get_columns()
         names = [scraper.get_name() for scraper in scrapers]
         maxlen = max([len(name) for name in names])
         namesPerLine = int(screenWidth / (maxlen + 1))

dosagelib/fileutil.py

@@ -0,0 +1,22 @@
+# -*- coding: iso-8859-1 -*-
+# Copyright (C) 2012 Bastian Kleineidam
+"""
+File and path utilities.
+"""
+
+def has_module (name):
+    """Test if given module can be imported.
+    @return: flag if import is successful
+    @rtype: bool
+    """
+    try:
+        exec "import %s as _bla" % name
+        return True
+    except (OSError, ImportError):
+        # some modules (for example HTMLtidy) raise OSError
+        return False
+
+
+def is_tty (fp):
+    """Check if a file object is a TTY."""
+    return (hasattr(fp, "isatty") and fp.isatty())

dosagelib/util.py

@@ -2,8 +2,6 @@ from __future__ import division
 
 import urllib2, urlparse
 import sys
-import struct
-import array
 import os
 import cgi
 import re
@@ -14,6 +12,12 @@ from math import log, floor
 
 from .output import out
 from .configuration import UserAgent, AppName, App, SupportUrl
+from .fileutil import has_module, is_tty
+
+has_wconio = has_module("WConio")
+has_curses = has_module("curses")
+has_fcntl = has_module('fcntl')
+has_termios = has_module('termios')
 
 class NoMatchError(Exception): pass
 
@@ -148,21 +152,41 @@ def urlopen(url, referrer=None, retries=5):
 
     return urlobj
 
-def getWindowSize():
+
+def get_columns (fp):
+    """Return number of columns for given file."""
+    if not is_tty(fp):
+        return 80
+    if has_wconio:
+        import WConio
+        # gettextinfo() returns a tuple
+        # - left, top, right, bottom: window coordinates
+        # - textattr, normattr: current attributes
+        # - videomode: current video mode
+        # - height, width: screen size
+        # - curx, cury: current cursor position
+        # return the width:
+        return WConio.gettextinfo()[8]
+    if has_curses:
+        import curses
         try:
-        from fcntl import ioctl
-        from termios import TIOCGWINSZ
-    except ImportError:
-        raise NotImplementedError
+            curses.setupterm()
+            return curses.tigetnum("cols")
+        except curses.error:
+           pass
+    if has_fcntl and has_termios:
+        import fcntl, termios, array, struct
         st = 'HHHH'
         names = 'ws_row', 'ws_col', 'ws_xpixel', 'ws_ypixel'
         buf = array.array('b', ' ' * struct.calcsize(st))
         try:
-        ioctl(sys.stderr, TIOCGWINSZ, buf, True)
-    except IOError:
-        raise NotImplementedError
+            fcntl.ioctl(fp, termios.TIOCGWINSZ, buf, True)
             winsize = dict(zip(names, struct.unpack(st, buf.tostring())))
             return winsize['ws_col']
+        except IOError:
+            pass
+    return 80
+
 
 suffixes = ('B', 'kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB', 'YB')