diff options
Diffstat (limited to 'git/cmd.py')
| -rw-r--r-- | git/cmd.py | 96 |
1 files changed, 96 insertions, 0 deletions
@@ -6,6 +6,7 @@ import os import sys +import select import logging from subprocess import ( call, @@ -36,9 +37,104 @@ log = logging.getLogger('git.cmd') __all__ = ('Git', ) +# ============================================================================== +## @name Utilities +# ------------------------------------------------------------------------------ +# Documentation +## @{ + +def handle_process_output(process, stdout_handler, stderr_handler, finalizer): + """Registers for notifications to lean that process output is ready to read, and dispatches lines to + the respective line handlers. We are able to handle carriage returns in case progress is sent by that + mean. For performance reasons, we only apply this to stderr. + This function returns once the finalizer returns + :return: result of finalizer + :param process: subprocess.Popen instance + :param stdout_handler: f(stdout_line_string), or None + :param stderr_hanlder: f(stderr_line_string), or None + :param finalizer: f(proc) - wait for proc to finish""" + def read_line_fast(stream): + return stream.readline() + + def read_line_slow(stream): + line = b'' + while True: + char = stream.read(1) # reads individual single byte strings + if not char: + break + + if char in (b'\r', b'\n') and line: + break + else: + line += char + # END process parsed line + # END while file is not done reading + return line + # end + + fdmap = { process.stdout.fileno() : (process.stdout, stdout_handler, read_line_fast), + process.stderr.fileno() : (process.stderr, stderr_handler, read_line_slow) } + + if hasattr(select, 'poll'): + def dispatch_line(fd): + stream, handler, readline = fdmap[fd] + # this can possibly block for a while, but since we wake-up with at least one or more lines to handle, + # we are good ... + line = readline(stream).decode(defenc) + if line and handler: + handler(line) + return line + # end dispatch helper + + # poll is preferred, as select is limited to file handles up to 1024 ... . Not an issue for us though, + # as we deal with relatively blank processes + poll = select.poll() + READ_ONLY = select.POLLIN | select.POLLPRI | select.POLLHUP | select.POLLERR + CLOSED = select.POLLHUP | select.POLLERR + + poll.register(process.stdout, READ_ONLY) + poll.register(process.stderr, READ_ONLY) + + closed_streams = set() + while True: + # no timeout + poll_result = poll.poll() + for fd, result in poll_result: + if result & CLOSED: + closed_streams.add(fd) + else: + dispatch_line(fd) + # end handle closed stream + # end for each poll-result tuple + + if len(closed_streams) == len(fdmap): + break + # end its all done + # end endless loop + + # Depelete all remaining buffers + for fno, _ in fdmap.items(): + while True: + line = dispatch_line(fno) + if not line: + break + # end deplete buffer + # end for each file handle + else: + # Oh ... probably we are on windows. select.select() can only handle sockets, we have files + # The only reliable way to do this now is to use threads and wait for both to finish + # Since the finalizer is expected to wait, we don't have to introduce our own wait primitive + raise NotImplementedError() + # end + + return finalizer(process) + + def dashify(string): return string.replace('_', '-') +## -- End Utilities -- @} + class Git(LazyMixin): |