Merge pull request #332 from python-cmd2/display_length_fix

Display length fix

5 files changed, 81 insertions, 86 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6d3b0c19..d405796c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@
     * Added more control over tab completion behavior including the following flags. The use of these flags is documented in cmd2.py
         * ``allow_appended_space``
         * ``allow_closing_quote``
+    * Due to the tab completion changes, non-Windows platforms now depend on [wcwidth](https://pypi.python.org/pypi/wcwidth).
 
 * Attribute Changes (Breaks backward compatibility)
     * ``exclude_from_help`` is now called ``hidden_commands`` since these commands are hidden from things other than help, including tab completion
diff --git a/README.md b/README.md
index 9ccb4d61..587fb104 100755
--- a/README.md
+++ b/README.md
@@ -61,7 +61,8 @@ pip install -U cmd2
 cmd2 works with Python 2.7 and Python 3.4+ on Windows, macOS, and Linux. It is pure Python code with
 the only 3rd-party dependencies being on [six](https://pypi.python.org/pypi/six),
 [pyparsing](http://pyparsing.wikispaces.com), and [pyperclip](https://github.com/asweigart/pyperclip).
-Windows has an additional dependency on [pyreadline](https://pypi.python.org/pypi/pyreadline) and Python
+Windows has an additional dependency on [pyreadline](https://pypi.python.org/pypi/pyreadline). Non-Windows platforms
+have an additional dependency on [wcwidth](https://pypi.python.org/pypi/wcwidth). Finally, Python
 3.4 and earlier have an additional dependency on [contextlib2](https://pypi.python.org/pypi/contextlib2).
 
 For information on other installation options, see
diff --git a/cmd2.py b/cmd2.py
index d5f82016..dbcbae14 100755
--- a/cmd2.py
+++ b/cmd2.py
@@ -153,6 +153,9 @@ if 'pyreadline' in sys.modules:
 elif 'gnureadline' in sys.modules or 'readline' in sys.modules:
     rl_type = RlType.GNU
 
+    # We need wcswidth to calculate display width of tab completions
+    from wcwidth import wcswidth
+
     # Load the readline lib so we can make changes to it
     import ctypes
     readline_lib = ctypes.CDLL(readline.__file__)
@@ -1268,55 +1271,6 @@ class Cmd(cmd.Cmd):
         self.allow_closing_quote = True
         self.display_matches = []
 
-    @staticmethod
-    def display_match_list_gnu_readline(substitution, matches, longest_match_length):
-        """
-        Prints a match list using GNU readline's rl_display_match_list()
-        :param substitution: str - the substitution written to the command line
-        :param matches: list[str] - the tab completion matches to display
-        :param longest_match_length: int - longest printed length of the matches
-        """
-        if rl_type == RlType.GNU:
-            # We will use readline's display function (rl_display_match_list()), so we
-            # need to encode our string as bytes to place in a C array.
-            if six.PY3:
-                encoded_substitution = bytes(substitution, encoding='utf-8')
-                encoded_matches = [bytes(cur_match, encoding='utf-8') for cur_match in matches]
-            else:
-                encoded_substitution = bytes(substitution)
-                encoded_matches = [bytes(cur_match) for cur_match in matches]
-
-            # rl_display_match_list() expects matches to be in argv format where
-            # substitution is the first element, followed by the matches, and then a NULL.
-            # noinspection PyCallingNonCallable,PyTypeChecker
-            strings_array = (ctypes.c_char_p * (1 + len(encoded_matches) + 1))()
-
-            # Copy in the encoded strings and add a NULL to the end
-            strings_array[0] = encoded_substitution
-            strings_array[1:-1] = encoded_matches
-            strings_array[-1] = None
-
-            # Call readline's display function
-            # rl_display_match_list(strings_array, number of completion matches, longest match length)
-            readline_lib.rl_display_match_list(strings_array, len(encoded_matches), longest_match_length)
-
-            # rl_forced_update_display() is the proper way to redraw the prompt and line, but we
-            # have to use ctypes to do it since Python's readline API does not wrap the function
-            readline_lib.rl_forced_update_display()
-
-            # Since we updated the display, readline asks that rl_display_fixed be set for efficiency
-            display_fixed = ctypes.c_int.in_dll(readline_lib, "rl_display_fixed")
-            display_fixed.value = 1
-
-    @staticmethod
-    def display_match_list_pyreadline(matches):
-        """
-        Prints a match list using pyreadline's _display_completions()
-        :param matches: list[str] - the tab completion matches to display
-        """
-        if rl_type == RlType.PYREADLINE:
-            orig_pyreadline_display(matches)
-
     def tokens_for_completion(self, line, begidx, endidx):
         """
         Used by tab completion functions to get all tokens through the one being completed
@@ -1548,7 +1502,7 @@ class Cmd(cmd.Cmd):
             if flag in flag_dict:
                 match_against = flag_dict[flag]
 
-        # Perform tab completion using an Collection. These matches are already sorted.
+        # Perform tab completion using a Collection. These matches are already sorted.
         if isinstance(match_against, Collection):
             completions_matches = self.basic_complete(text, line, begidx, endidx, match_against)
 
@@ -1592,7 +1546,7 @@ class Cmd(cmd.Cmd):
         else:
             match_against = all_else
 
-        # Perform tab completion using an Collection. These matches are already sorted.
+        # Perform tab completion using a Collection. These matches are already sorted.
         if isinstance(match_against, Collection):
             matches = self.basic_complete(text, line, begidx, endidx, match_against)
 
@@ -1817,55 +1771,87 @@ class Cmd(cmd.Cmd):
 
     def _display_matches_gnu_readline(self, substitution, matches, longest_match_length):
         """
-        cmd2's default GNU readline function that prints tab-completion matches to the screen
-        This exists to allow the printing of self.display_matches if it has data. Otherwise matches prints.
-        The actual printing is done by display_match_list_gnu_readline().
-
-        If you need a custom match display function for a particular completion type, then set it by calling
-        readline.set_completion_display_matches_hook() during the completer routine.
-        Your custom display function should ultimately call display_match_list_gnu_readline() to print.
+        Prints a match list using GNU readline's rl_display_match_list()
+        This exists to print self.display_matches if it has data. Otherwise matches prints.
 
         :param substitution: str - the substitution written to the command line
         :param matches: list[str] - the tab completion matches to display
         :param longest_match_length: int - longest printed length of the matches
         """
-        if len(self.display_matches) > 0:
-            matches_to_display = self.display_matches
-        else:
-            matches_to_display = matches
+        if rl_type == RlType.GNU:
+
+            # Check if we should show display_matches
+            if len(self.display_matches) > 0:
+                matches_to_display = self.display_matches
+
+                # Recalculate longest_match_length for display_matches
+                longest_match_length = 0
+
+                for cur_match in matches_to_display:
+                    cur_length = wcswidth(cur_match)
+                    if cur_length > longest_match_length:
+                        longest_match_length = cur_length
+            else:
+                matches_to_display = matches
+
+            # Eliminate duplicates and sort
+            matches_to_display_set = set(matches_to_display)
+            matches_to_display = list(matches_to_display_set)
+            matches_to_display.sort()
+
+            # We will use readline's display function (rl_display_match_list()), so we
+            # need to encode our string as bytes to place in a C array.
+            if six.PY3:
+                encoded_substitution = bytes(substitution, encoding='utf-8')
+                encoded_matches = [bytes(cur_match, encoding='utf-8') for cur_match in matches_to_display]
+            else:
+                encoded_substitution = bytes(substitution)
+                encoded_matches = [bytes(cur_match) for cur_match in matches_to_display]
+
+            # rl_display_match_list() expects matches to be in argv format where
+            # substitution is the first element, followed by the matches, and then a NULL.
+            # noinspection PyCallingNonCallable,PyTypeChecker
+            strings_array = (ctypes.c_char_p * (1 + len(encoded_matches) + 1))()
 
-        # Eliminate duplicates and sort
-        matches_to_display_set = set(matches_to_display)
-        matches_to_display = list(matches_to_display_set)
-        matches_to_display.sort()
+            # Copy in the encoded strings and add a NULL to the end
+            strings_array[0] = encoded_substitution
+            strings_array[1:-1] = encoded_matches
+            strings_array[-1] = None
+
+            # Call readline's display function
+            # rl_display_match_list(strings_array, number of completion matches, longest match length)
+            readline_lib.rl_display_match_list(strings_array, len(encoded_matches), longest_match_length)
+
+            # rl_forced_update_display() is the proper way to redraw the prompt and line, but we
+            # have to use ctypes to do it since Python's readline API does not wrap the function
+            readline_lib.rl_forced_update_display()
 
-        # Display the matches
-        self.display_match_list_gnu_readline(substitution, matches_to_display, longest_match_length)
+            # Since we updated the display, readline asks that rl_display_fixed be set for efficiency
+            display_fixed = ctypes.c_int.in_dll(readline_lib, "rl_display_fixed")
+            display_fixed.value = 1
 
     def _display_matches_pyreadline(self, matches):
         """
-        cmd2's default pyreadline function that prints tab-completion matches to the screen
-        This exists to allow the printing of self.display_matches if it has data. Otherwise matches prints.
-        The actual printing is done by display_match_list_pyreadline().
-
-        If you need a custom match display function for a particular completion type, then set
-        readline.rl.mode._display_completions to that function during the completer routine.
-        Your custom display function should ultimately call display_match_list_pyreadline() to print.
+        Prints a match list using pyreadline's _display_completions()
+        This exists to print self.display_matches if it has data. Otherwise matches prints.
 
         :param matches: list[str] - the tab completion matches to display
         """
-        if len(self.display_matches) > 0:
-            matches_to_display = self.display_matches
-        else:
-            matches_to_display = matches
+        if rl_type == RlType.PYREADLINE:
 
-        # Eliminate duplicates and sort
-        matches_to_display_set = set(matches_to_display)
-        matches_to_display = list(matches_to_display_set)
-        matches_to_display.sort()
+            # Check if we should show display_matches
+            if len(self.display_matches) > 0:
+                matches_to_display = self.display_matches
+            else:
+                matches_to_display = matches
+
+            # Eliminate duplicates and sort
+            matches_to_display_set = set(matches_to_display)
+            matches_to_display = list(matches_to_display_set)
+            matches_to_display.sort()
 
-        # Display the matches
-        self.display_match_list_pyreadline(matches_to_display)
+            # Display the matches
+            orig_pyreadline_display(matches_to_display)
 
     def _handle_completion_token_quote(self, raw_completion_token):
         """
diff --git a/setup.py b/setup.py
index 8107552d..424a4275 100755
--- a/setup.py
+++ b/setup.py
@@ -81,6 +81,8 @@ if int(setuptools.__version__.split('.')[0]) < 18:
     EXTRAS_REQUIRE = {}
     if sys.platform.startswith('win'):
         INSTALL_REQUIRES.append('pyreadline')
+    else:
+        INSTALL_REQUIRES.append('wcwidth')
     if sys.version_info < (3, 5):
         INSTALL_REQUIRES.append('contextlib2')
     if sys.version_info < (3, 4):
diff --git a/tox.ini b/tox.ini
index 1be182f4..40855318 100644
--- a/tox.ini
+++ b/tox.ini
@@ -22,6 +22,7 @@ deps =
   pytest-xdist
   six
   subprocess32
+  wcwidth
 commands =
   py.test {posargs: -n 2} --cov=cmd2 --cov-report=term-missing --forked
   codecov
@@ -52,6 +53,7 @@ deps =
   pytest-forked
   pytest-xdist
   six
+  wcwidth
 commands = py.test -v -n2 --forked
 
 [testenv:py35]
@@ -63,6 +65,7 @@ deps =
   pytest-forked
   pytest-xdist
   six
+  wcwidth
 commands = py.test -v -n2 --forked
 
 [testenv:py35-win]
@@ -87,6 +90,7 @@ deps =
   pytest-forked
   pytest-xdist
   six
+  wcwidth
 commands =
   py.test {posargs: -n 2} --cov=cmd2 --cov-report=term-missing --forked
   codecov
@@ -111,5 +115,6 @@ deps =
   pytest-forked
   pytest-xdist
   six
+  wcwidth
 commands = py.test -v -n2 --forked