Initial customization of CompletionFinder

3 files changed, 224 insertions, 17 deletions

diff --git a/cmd2/__init__.py b/cmd2/__init__.py
index 8e744e03..773eba37 100644
--- a/cmd2/__init__.py
+++ b/cmd2/__init__.py
@@ -3,3 +3,20 @@
 #
 from .cmd2 import __version__, Cmd, set_posix_shlex, set_strip_quotes, AddSubmenu, CmdResult, categorize
 from .cmd2 import with_argument_list, with_argparser, with_argparser_and_unknown_args, with_category
+
+# Used for tab completion and word breaks. Do not change.
+QUOTES = ['"', "'"]
+REDIRECTION_CHARS = ['|', '<', '>']
+
+
+def strip_quotes(arg: str) -> str:
+    """ Strip outer quotes from a string.
+
+     Applies to both single and double quotes.
+
+    :param arg:  string to strip outer quotes from
+    :return: same string with potentially outer quotes stripped
+    """
+    if len(arg) > 1 and arg[0] == arg[-1] and arg[0] in QUOTES:
+        arg = arg[1:-1]
+    return arg
diff --git a/cmd2/argcomplete_bridge.py b/cmd2/argcomplete_bridge.py
new file mode 100644
index 00000000..93b3cbbb
--- /dev/null
+++ b/cmd2/argcomplete_bridge.py
@@ -0,0 +1,206 @@
+# coding=utf-8
+"""Hijack the ArgComplete's bash completion handler to return AutoCompleter results"""
+
+import argcomplete
+import copy
+import os
+import shlex
+import sys
+
+from . import strip_quotes, QUOTES
+
+
+def tokens_for_completion(line, endidx):
+    """
+    Used by tab completion functions to get all tokens through the one being completed
+    :param line: str - the current input line with leading whitespace removed
+    :param endidx: int - the ending index of the prefix text
+    :return: A 4 item tuple where the items are
+             On Success
+                 tokens: list of unquoted tokens
+                         this is generally the list needed for tab completion functions
+                 raw_tokens: list of tokens with any quotes preserved
+                             this can be used to know if a token was quoted or is missing a closing quote
+                 begidx: beginning of last token
+                 endidx: cursor position
+
+                 Both lists are guaranteed to have at least 1 item
+                 The last item in both lists is the token being tab completed
+
+             On Failure
+                Both items are None
+    """
+    unclosed_quote = ''
+    quotes_to_try = copy.copy(QUOTES)
+
+    tmp_line = line[:endidx]
+    tmp_endidx = endidx
+
+    # Parse the line into tokens
+    while True:
+        try:
+            # Use non-POSIX parsing to keep the quotes around the tokens
+            initial_tokens = shlex.split(tmp_line[:tmp_endidx], posix=False)
+
+            # calculate begidx
+            if unclosed_quote:
+                begidx = tmp_line[:tmp_endidx].rfind(initial_tokens[-1]) + 1
+            else:
+                if tmp_endidx > 0 and tmp_line[tmp_endidx - 1] == ' ':
+                    begidx = endidx
+                else:
+                    begidx = tmp_line[:tmp_endidx].rfind(initial_tokens[-1])
+
+            # If the cursor is at an empty token outside of a quoted string,
+            # then that is the token being completed. Add it to the list.
+            if not unclosed_quote and begidx == tmp_endidx:
+                initial_tokens.append('')
+            break
+        except ValueError:
+            # ValueError can be caused by missing closing quote
+            if not quotes_to_try:
+                # Since we have no more quotes to try, something else
+                # is causing the parsing error. Return None since
+                # this means the line is malformed.
+                return None, None, None, None
+
+            # Add a closing quote and try to parse again
+            unclosed_quote = quotes_to_try[0]
+            quotes_to_try = quotes_to_try[1:]
+
+            tmp_line = line[:endidx]
+            tmp_line += unclosed_quote
+            tmp_endidx = endidx + 1
+
+    raw_tokens = initial_tokens
+
+    # Save the unquoted tokens
+    tokens = [strip_quotes(cur_token) for cur_token in raw_tokens]
+
+    # If the token being completed had an unclosed quote, we need
+    # to remove the closing quote that was added in order for it
+    # to match what was on the command line.
+    if unclosed_quote:
+        raw_tokens[-1] = raw_tokens[-1][:-1]
+
+    return tokens, raw_tokens, begidx, endidx
+
+class CompletionFinder(argcomplete.CompletionFinder):
+    """Hijack the functor from argcomplete to call AutoCompleter"""
+
+    def __call__(self, argument_parser, completer=None, always_complete_options=True, exit_method=os._exit, output_stream=None,
+                 exclude=None, validator=None, print_suppressed=False, append_space=None,
+                 default_completer=argcomplete.FilesCompleter()):
+        """
+        :param argument_parser: The argument parser to autocomplete on
+        :type argument_parser: :class:`argparse.ArgumentParser`
+        :param always_complete_options:
+            Controls the autocompletion of option strings if an option string opening character (normally ``-``) has not
+            been entered. If ``True`` (default), both short (``-x``) and long (``--x``) option strings will be
+            suggested. If ``False``, no option strings will be suggested. If ``long``, long options and short options
+            with no long variant will be suggested. If ``short``, short options and long options with no short variant
+            will be suggested.
+        :type always_complete_options: boolean or string
+        :param exit_method:
+            Method used to stop the program after printing completions. Defaults to :meth:`os._exit`. If you want to
+            perform a normal exit that calls exit handlers, use :meth:`sys.exit`.
+        :type exit_method: callable
+        :param exclude: List of strings representing options to be omitted from autocompletion
+        :type exclude: iterable
+        :param validator:
+            Function to filter all completions through before returning (called with two string arguments, completion
+            and prefix; return value is evaluated as a boolean)
+        :type validator: callable
+        :param print_suppressed:
+            Whether or not to autocomplete options that have the ``help=argparse.SUPPRESS`` keyword argument set.
+        :type print_suppressed: boolean
+        :param append_space:
+            Whether to append a space to unique matches. The default is ``True``.
+        :type append_space: boolean
+
+        .. note::
+            If you are not subclassing CompletionFinder to override its behaviors,
+            use ``argcomplete.autocomplete()`` directly. It has the same signature as this method.
+
+        Produces tab completions for ``argument_parser``. See module docs for more info.
+
+        Argcomplete only executes actions if their class is known not to have side effects. Custom action classes can be
+        added to argcomplete.safe_actions, if their values are wanted in the ``parsed_args`` completer argument, or
+        their execution is otherwise desirable.
+        """
+        self.__init__(argument_parser, always_complete_options=always_complete_options, exclude=exclude,
+                      validator=validator, print_suppressed=print_suppressed, append_space=append_space,
+                      default_completer=default_completer)
+
+        if "_ARGCOMPLETE" not in os.environ:
+            # not an argument completion invocation
+            return
+
+        global debug_stream
+        try:
+            debug_stream = os.fdopen(9, "w")
+        except:
+            debug_stream = sys.stderr
+
+        if output_stream is None:
+            try:
+                output_stream = os.fdopen(8, "wb")
+            except:
+                argcomplete.debug("Unable to open fd 8 for writing, quitting")
+                exit_method(1)
+
+        # print("", stream=debug_stream)
+        # for v in "COMP_CWORD COMP_LINE COMP_POINT COMP_TYPE COMP_KEY _ARGCOMPLETE_COMP_WORDBREAKS COMP_WORDS".split():
+        #     print(v, os.environ[v], stream=debug_stream)
+
+        ifs = os.environ.get("_ARGCOMPLETE_IFS", "\013")
+        if len(ifs) != 1:
+            argcomplete.debug("Invalid value for IFS, quitting [{v}]".format(v=ifs))
+            exit_method(1)
+
+        comp_line = os.environ["COMP_LINE"]
+        comp_point = int(os.environ["COMP_POINT"])
+
+        comp_line = argcomplete.ensure_str(comp_line)
+        ### SWAPPED FOR AUTOCOMPLETER
+        # cword_prequote, cword_prefix, cword_suffix, comp_words, last_wordbreak_pos = split_line(comp_line, comp_point)
+        tokens, _, begidx, endidx = tokens_for_completion(comp_line, comp_point)
+
+        # _ARGCOMPLETE is set by the shell script to tell us where comp_words
+        # should start, based on what we're completing.
+        # 1: <script> [args]
+        # 2: python <script> [args]
+        # 3: python -m <module> [args]
+        start = int(os.environ["_ARGCOMPLETE"]) - 1
+        ### SWAPPED FOR AUTOCOMPLETER
+        # comp_words = comp_words[start:]
+        tokens = tokens[start:]
+
+        # debug("\nLINE: {!r}".format(comp_line),
+        #       "\nPOINT: {!r}".format(comp_point),
+        #       "\nPREQUOTE: {!r}".format(cword_prequote),
+        #       "\nPREFIX: {!r}".format(cword_prefix),
+        #       "\nSUFFIX: {!r}".format(cword_suffix),
+        #       "\nWORDS:", comp_words)
+
+        ### SWAPPED FOR AUTOCOMPLETER
+        # completions = self._get_completions(comp_words, cword_prefix, cword_prequote, last_wordbreak_pos)
+        completions = completer.complete_command(tokens, tokens[-1], comp_line, begidx, endidx)
+
+        if completions is not None:
+            # If any completion has a space in it, then quote all completions
+            # this improves the user experience so they don't nede to go back and add a quote
+            if ' ' in ''.join(completions):
+                completions = ['"{}"'.format(entry) for entry in completions]
+
+            argcomplete.debug("\nReturning completions:", completions)
+
+            output_stream.write(ifs.join(completions).encode(argcomplete.sys_encoding))
+        else:
+            # if completions is None we assume we don't know how to handle it so let bash
+            # go forward with normal filesystem completion
+            output_stream.write(ifs.join([]).encode(argcomplete.sys_encoding))
+        output_stream.flush()
+        debug_stream.flush()
+        exit_method(0)
+
diff --git a/cmd2/cmd2.py b/cmd2/cmd2.py
index 8d8a5b07..e4f8c7c8 100755
--- a/cmd2/cmd2.py
+++ b/cmd2/cmd2.py
@@ -135,8 +135,7 @@ POSIX_SHLEX = False
 STRIP_QUOTES_FOR_NON_POSIX = True
 
 # Used for tab completion and word breaks. Do not change.
-QUOTES = ['"', "'"]
-REDIRECTION_CHARS = ['|', '<', '>']
+from . import strip_quotes, QUOTES, REDIRECTION_CHARS
 
 # optional attribute, when tagged on a function, allows cmd2 to categorize commands
 HELP_CATEGORY = 'help_category'
@@ -185,21 +184,6 @@ def _which(editor: str) -> Optional[str]:
     return editor_path
 
 
-def strip_quotes(arg: str) -> str:
-    """ Strip outer quotes from a string.
-
-     Applies to both single and double quotes.
-
-    :param arg:  string to strip outer quotes from
-    :return: same string with potentially outer quotes stripped
-    """
-    quote_chars = '"' + "'"
-
-    if len(arg) > 1 and arg[0] == arg[-1] and arg[0] in quote_chars:
-        arg = arg[1:-1]
-    return arg
-
-
 def parse_quoted_string(cmdline: str) -> List[str]:
     """Parse a quoted string into a list of arguments."""
     if isinstance(cmdline, list):