--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lib/python3.8/site-packages/pip/_internal/utils/subprocess.py	Mon Jul 27 03:47:31 2020 -0400
@@ -0,0 +1,278 @@
+# The following comment should be removed at some point in the future.
+# mypy: strict-optional=False
+
+from __future__ import absolute_import
+
+import logging
+import os
+import subprocess
+
+from pip._vendor.six.moves import shlex_quote
+
+from pip._internal.exceptions import InstallationError
+from pip._internal.utils.compat import console_to_str, str_to_display
+from pip._internal.utils.logging import subprocess_logger
+from pip._internal.utils.misc import HiddenText, path_to_display
+from pip._internal.utils.typing import MYPY_CHECK_RUNNING
+from pip._internal.utils.ui import open_spinner
+
+if MYPY_CHECK_RUNNING:
+    from typing import (
+        Any, Callable, Iterable, List, Mapping, Optional, Text, Union,
+    )
+    from pip._internal.utils.ui import SpinnerInterface
+
+    CommandArgs = List[Union[str, HiddenText]]
+
+
+LOG_DIVIDER = '----------------------------------------'
+
+
+def make_command(*args):
+    # type: (Union[str, HiddenText, CommandArgs]) -> CommandArgs
+    """
+    Create a CommandArgs object.
+    """
+    command_args = []  # type: CommandArgs
+    for arg in args:
+        # Check for list instead of CommandArgs since CommandArgs is
+        # only known during type-checking.
+        if isinstance(arg, list):
+            command_args.extend(arg)
+        else:
+            # Otherwise, arg is str or HiddenText.
+            command_args.append(arg)
+
+    return command_args
+
+
+def format_command_args(args):
+    # type: (Union[List[str], CommandArgs]) -> str
+    """
+    Format command arguments for display.
+    """
+    # For HiddenText arguments, display the redacted form by calling str().
+    # Also, we don't apply str() to arguments that aren't HiddenText since
+    # this can trigger a UnicodeDecodeError in Python 2 if the argument
+    # has type unicode and includes a non-ascii character.  (The type
+    # checker doesn't ensure the annotations are correct in all cases.)
+    return ' '.join(
+        shlex_quote(str(arg)) if isinstance(arg, HiddenText)
+        else shlex_quote(arg) for arg in args
+    )
+
+
+def reveal_command_args(args):
+    # type: (Union[List[str], CommandArgs]) -> List[str]
+    """
+    Return the arguments in their raw, unredacted form.
+    """
+    return [
+        arg.secret if isinstance(arg, HiddenText) else arg for arg in args
+    ]
+
+
+def make_subprocess_output_error(
+    cmd_args,     # type: Union[List[str], CommandArgs]
+    cwd,          # type: Optional[str]
+    lines,        # type: List[Text]
+    exit_status,  # type: int
+):
+    # type: (...) -> Text
+    """
+    Create and return the error message to use to log a subprocess error
+    with command output.
+
+    :param lines: A list of lines, each ending with a newline.
+    """
+    command = format_command_args(cmd_args)
+    # Convert `command` and `cwd` to text (unicode in Python 2) so we can use
+    # them as arguments in the unicode format string below. This avoids
+    # "UnicodeDecodeError: 'ascii' codec can't decode byte ..." in Python 2
+    # if either contains a non-ascii character.
+    command_display = str_to_display(command, desc='command bytes')
+    cwd_display = path_to_display(cwd)
+
+    # We know the joined output value ends in a newline.
+    output = ''.join(lines)
+    msg = (
+        # Use a unicode string to avoid "UnicodeEncodeError: 'ascii'
+        # codec can't encode character ..." in Python 2 when a format
+        # argument (e.g. `output`) has a non-ascii character.
+        u'Command errored out with exit status {exit_status}:\n'
+        ' command: {command_display}\n'
+        '     cwd: {cwd_display}\n'
+        'Complete output ({line_count} lines):\n{output}{divider}'
+    ).format(
+        exit_status=exit_status,
+        command_display=command_display,
+        cwd_display=cwd_display,
+        line_count=len(lines),
+        output=output,
+        divider=LOG_DIVIDER,
+    )
+    return msg
+
+
+def call_subprocess(
+    cmd,  # type: Union[List[str], CommandArgs]
+    show_stdout=False,  # type: bool
+    cwd=None,  # type: Optional[str]
+    on_returncode='raise',  # type: str
+    extra_ok_returncodes=None,  # type: Optional[Iterable[int]]
+    command_desc=None,  # type: Optional[str]
+    extra_environ=None,  # type: Optional[Mapping[str, Any]]
+    unset_environ=None,  # type: Optional[Iterable[str]]
+    spinner=None,  # type: Optional[SpinnerInterface]
+    log_failed_cmd=True  # type: Optional[bool]
+):
+    # type: (...) -> Text
+    """
+    Args:
+      show_stdout: if true, use INFO to log the subprocess's stderr and
+        stdout streams.  Otherwise, use DEBUG.  Defaults to False.
+      extra_ok_returncodes: an iterable of integer return codes that are
+        acceptable, in addition to 0. Defaults to None, which means [].
+      unset_environ: an iterable of environment variable names to unset
+        prior to calling subprocess.Popen().
+      log_failed_cmd: if false, failed commands are not logged, only raised.
+    """
+    if extra_ok_returncodes is None:
+        extra_ok_returncodes = []
+    if unset_environ is None:
+        unset_environ = []
+    # Most places in pip use show_stdout=False. What this means is--
+    #
+    # - We connect the child's output (combined stderr and stdout) to a
+    #   single pipe, which we read.
+    # - We log this output to stderr at DEBUG level as it is received.
+    # - If DEBUG logging isn't enabled (e.g. if --verbose logging wasn't
+    #   requested), then we show a spinner so the user can still see the
+    #   subprocess is in progress.
+    # - If the subprocess exits with an error, we log the output to stderr
+    #   at ERROR level if it hasn't already been displayed to the console
+    #   (e.g. if --verbose logging wasn't enabled).  This way we don't log
+    #   the output to the console twice.
+    #
+    # If show_stdout=True, then the above is still done, but with DEBUG
+    # replaced by INFO.
+    if show_stdout:
+        # Then log the subprocess output at INFO level.
+        log_subprocess = subprocess_logger.info
+        used_level = logging.INFO
+    else:
+        # Then log the subprocess output using DEBUG.  This also ensures
+        # it will be logged to the log file (aka user_log), if enabled.
+        log_subprocess = subprocess_logger.debug
+        used_level = logging.DEBUG
+
+    # Whether the subprocess will be visible in the console.
+    showing_subprocess = subprocess_logger.getEffectiveLevel() <= used_level
+
+    # Only use the spinner if we're not showing the subprocess output
+    # and we have a spinner.
+    use_spinner = not showing_subprocess and spinner is not None
+
+    if command_desc is None:
+        command_desc = format_command_args(cmd)
+
+    log_subprocess("Running command %s", command_desc)
+    env = os.environ.copy()
+    if extra_environ:
+        env.update(extra_environ)
+    for name in unset_environ:
+        env.pop(name, None)
+    try:
+        proc = subprocess.Popen(
+            # Convert HiddenText objects to the underlying str.
+            reveal_command_args(cmd),
+            stderr=subprocess.STDOUT, stdin=subprocess.PIPE,
+            stdout=subprocess.PIPE, cwd=cwd, env=env,
+        )
+        proc.stdin.close()
+    except Exception as exc:
+        if log_failed_cmd:
+            subprocess_logger.critical(
+                "Error %s while executing command %s", exc, command_desc,
+            )
+        raise
+    all_output = []
+    while True:
+        # The "line" value is a unicode string in Python 2.
+        line = console_to_str(proc.stdout.readline())
+        if not line:
+            break
+        line = line.rstrip()
+        all_output.append(line + '\n')
+
+        # Show the line immediately.
+        log_subprocess(line)
+        # Update the spinner.
+        if use_spinner:
+            spinner.spin()
+    try:
+        proc.wait()
+    finally:
+        if proc.stdout:
+            proc.stdout.close()
+    proc_had_error = (
+        proc.returncode and proc.returncode not in extra_ok_returncodes
+    )
+    if use_spinner:
+        if proc_had_error:
+            spinner.finish("error")
+        else:
+            spinner.finish("done")
+    if proc_had_error:
+        if on_returncode == 'raise':
+            if not showing_subprocess and log_failed_cmd:
+                # Then the subprocess streams haven't been logged to the
+                # console yet.
+                msg = make_subprocess_output_error(
+                    cmd_args=cmd,
+                    cwd=cwd,
+                    lines=all_output,
+                    exit_status=proc.returncode,
+                )
+                subprocess_logger.error(msg)
+            exc_msg = (
+                'Command errored out with exit status {}: {} '
+                'Check the logs for full command output.'
+            ).format(proc.returncode, command_desc)
+            raise InstallationError(exc_msg)
+        elif on_returncode == 'warn':
+            subprocess_logger.warning(
+                'Command "%s" had error code %s in %s',
+                command_desc, proc.returncode, cwd,
+            )
+        elif on_returncode == 'ignore':
+            pass
+        else:
+            raise ValueError('Invalid value: on_returncode=%s' %
+                             repr(on_returncode))
+    return ''.join(all_output)
+
+
+def runner_with_spinner_message(message):
+    # type: (str) -> Callable[..., None]
+    """Provide a subprocess_runner that shows a spinner message.
+
+    Intended for use with for pep517's Pep517HookCaller. Thus, the runner has
+    an API that matches what's expected by Pep517HookCaller.subprocess_runner.
+    """
+
+    def runner(
+        cmd,  # type: List[str]
+        cwd=None,  # type: Optional[str]
+        extra_environ=None  # type: Optional[Mapping[str, Any]]
+    ):
+        # type: (...) -> None
+        with open_spinner(message) as spinner:
+            call_subprocess(
+                cmd,
+                cwd=cwd,
+                extra_environ=extra_environ,
+                spinner=spinner,
+            )
+
+    return runner