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# Source code for xonsh.completer

    """A (tab-)completer for xonsh."""

    import collections.abc as cabc
    import sys
    import typing as tp

    from xonsh.built_ins import XSH
    from xonsh.completers.tools import (
        Completion,
        RichCompletion,
        apply_lprefix,
        get_filter_function,
        is_contextual_completer,
        is_exclusive_completer,
    )
    from xonsh.parsers.completion_context import CompletionContext, CompletionContextParser
    from xonsh.tools import print_exception

    class Completer:
        """This provides a list of optional completions for the xonsh shell."""

        def __init__(self):
            self.context_parser = CompletionContextParser()

        def parse(
            self, text: str, cursor_index: "None|int" = None, ctx=None
        ) -> "CompletionContext":
            """Parse the given text

            Parameters
            ----------
            text
                multi-line text
            cursor_index
                position of the cursor. If not given, then it is considered to be at the end.
            ctx
                Execution context
            """
            cursor_index = len(text) if cursor_index is None else cursor_index
            return self.context_parser.parse(text, cursor_index, ctx)

        def complete_line(self, text: str):
            """Handy wrapper to build command-completion-context when cursor is at the end.

            Notes
            -----
            suffix is not supported; text after last space is parsed as prefix.
            """
            ctx = self.parse(text)

            if not ctx:
                raise RuntimeError("CompletionContext is None")

            if ctx.python is not None:
                prefix = ctx.python.prefix
            elif ctx.command is not None:
                prefix = ctx.command.prefix
            else:
                raise RuntimeError("CompletionContext is empty")

            line = text
            begidx = text.rfind(prefix)
            endidx = begidx + len(prefix)

            return self.complete(
                prefix,
                line,
                begidx,
                endidx,
                cursor_index=len(line),
                multiline_text=line,
                completion_context=ctx,
            )

        def complete(
            self,
            prefix,
            line,
            begidx,
            endidx,
            ctx=None,
            multiline_text=None,
            cursor_index=None,
            completion_context=None,
        ):
            """Complete the string, given a possible execution context.

            Parameters
            ----------
            prefix : str
                The string to match
            line : str
                The line that prefix appears on.
            begidx : int
                The index in line that prefix starts on.
            endidx : int
                The index in line that prefix ends on.
            ctx : dict, optional
                Names in the current execution context.
            multiline_text : str
                The complete multiline text. Needed to get completion context.
            cursor_index : int
                The current cursor's index in the multiline text.
                May be ``len(multiline_text)`` for cursor at the end.
                Needed to get completion context.

            Returns
            -------
            rtn : list of str
                Possible completions of prefix, sorted alphabetically.
            lprefix : int
                Length of the prefix to be replaced in the completion.
            """

            if (
                (multiline_text is not None)
                and (cursor_index is not None)
                and (completion_context is None)
            ):
                completion_context: CompletionContext | None = self.parse(
                    multiline_text,
                    cursor_index,
                    ctx,
                )

            ctx = ctx or {}
            return self.complete_from_context(
                completion_context,
                (prefix, line, begidx, endidx, ctx),
            )

        @staticmethod
        def _format_completion(
            completion,
            completion_context,
            completing_contextual_command: bool,
            lprefix: int,
            custom_lprefix: bool,
        ) -> tuple[Completion, int]:
            if (
                completing_contextual_command
                and completion_context.command.is_after_closing_quote
            ):
                """
                The cursor is appending to a closed string literal, i.e. cursor at the end of ``ls "/usr/"``.
                1. The closing quote will be appended to all completions.
                    I.e the completion ``/usr/bin`` will turn into ``/usr/bin"``
                    To prevent this behavior, a completer can return a ``RichCompletion`` with ``append_closing_quote=False``.
                2. If not specified, lprefix will cover the closing prefix.
                    I.e for ``ls "/usr/"``, the default lprefix will be 6 to include the closing quote.
                    To prevent this behavior, a completer can return a different lprefix or specify it inside ``RichCompletion``.
                """
                closing_quote = completion_context.command.closing_quote
                if not custom_lprefix:
                    lprefix += len(closing_quote)
                if closing_quote:
                    if isinstance(completion, RichCompletion):
                        if completion.append_closing_quote:
                            completion = completion.replace(
                                value=completion.value + closing_quote
                            )
                    else:
                        completion = completion + closing_quote

            completion = list(apply_lprefix([completion], lprefix))[0]

            if (
                isinstance(completion, RichCompletion)
                and completion.append_space
                and not completion.value.endswith(" ")
            ):
                # append spaces AFTER appending closing quote
                completion = completion.replace(value=completion.value + " ")

            return completion, lprefix

        @staticmethod
        def generate_completions(
            completion_context, old_completer_args, trace: bool
        ) -> tp.Iterator[tuple[Completion, int]]:
            filter_func = get_filter_function()

            for name, func in XSH.completers.items():
                try:
                    if is_contextual_completer(func):
                        if completion_context is None:
                            continue
                        out = func(completion_context)
                    else:
                        if old_completer_args is None:
                            continue
                        out = func(*old_completer_args)
                except StopIteration:
                    # completer requested to stop collecting completions
                    break
                except Exception as e:
                    name = func.__name__ if hasattr(func, "__name__") else str(func)
                    print_exception(
                        f"Completer {name} raises exception when gets "
                        f"old_args={old_completer_args[:-1]} / completion_context={completion_context!r}:\n"
                        f"{type(e)} - {e}"
                    )
                    continue

                completing_contextual_command = (
                    is_contextual_completer(func)
                    and completion_context is not None
                    and completion_context.command is not None
                )

                # -- set comp-defaults --

                # the default is that the completer function filters out as necessary
                # we can change that once fuzzy/substring matches are added
                is_filtered = True
                custom_lprefix = False
                prefix = ""
                if completing_contextual_command:
                    prefix = completion_context.command.prefix
                elif old_completer_args is not None:
                    prefix = old_completer_args[0]
                lprefix = len(prefix)

                if isinstance(out, cabc.Sequence):
                    # update comp-defaults from
                    res, lprefix_filtered = out
                    if isinstance(lprefix_filtered, bool):
                        is_filtered = lprefix_filtered
                    else:
                        lprefix = lprefix_filtered
                        custom_lprefix = True
                else:
                    res = out

                if res is None:
                    continue

                items = []
                for comp in res:
                    if (not is_filtered) and (not filter_func(comp, prefix)):
                        continue
                    comp = Completer._format_completion(
                        comp,
                        completion_context,
                        completing_contextual_command,
                        lprefix or 0,
                        custom_lprefix,
                    )
                    items.append(comp)
                    yield comp

                if not items:  # empty completion
                    continue

                if trace:
                    print(
                        f"TRACE COMPLETIONS: Got {len(items)} results"
                        f" from {'' if is_exclusive_completer(func) else 'non-'}exclusive completer '{name}':"
                    )
                    sys.displayhook(items)

                if is_exclusive_completer(func):
                    # we got completions for an exclusive completer
                    break

        def complete_from_context(self, completion_context, old_completer_args=None):
            trace = XSH.env.get("XONSH_TRACE_COMPLETIONS")
            if trace:
                print("\nTRACE COMPLETIONS: Getting completions with context:")
                sys.displayhook(completion_context)
            lprefix = 0

            # using dict to keep order py3.6+
            completions = {}

            query_limit = XSH.env.get("COMPLETION_QUERY_LIMIT")

            for comp in self.generate_completions(
                completion_context,
                old_completer_args,
                trace,
            ):
                completion, lprefix = comp
                completions[completion] = None
                if query_limit and len(completions) >= query_limit:
                    if trace:
                        print(
                            "TRACE COMPLETIONS: Stopped after $COMPLETION_QUERY_LIMIT reached."
                        )
                    break

            if completion_context:
                if completion_context.python is not None:
                    prefix = completion_context.python.prefix
                elif completion_context.command is not None:
                    prefix = completion_context.command.prefix
                else:
                    raise RuntimeError("Completion context is empty")

                if prefix.startswith("$"):
                    prefix = prefix[1:]

                def sortkey(s):
                    """Sort values by prefix position and then alphabetically."""
                    return (s.lower().find(prefix.lower()), s.lower())
            else:
                # Fallback sort.
                sortkey = lambda s: s.lstrip(''''"''').lower()

            # the last completer's lprefix is returned. other lprefix values are inside the RichCompletions.
            return tuple(sorted(completions, key=sortkey)), lprefix