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Diffstat (limited to 'git_remote_helpers/util.py')
| -rw-r--r-- | git_remote_helpers/util.py | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/git_remote_helpers/util.py b/git_remote_helpers/util.py new file mode 100644 index 0000000..dce83e6 --- /dev/null +++ b/git_remote_helpers/util.py @@ -0,0 +1,194 @@ +#!/usr/bin/env python + +"""Misc. useful functionality used by the rest of this package. + +This module provides common functionality used by the other modules in +this package. + +""" + +import sys +import os +import subprocess + + +# Whether or not to show debug messages +DEBUG = False + +def notify(msg, *args): + """Print a message to stderr.""" + print >> sys.stderr, msg % args + +def debug (msg, *args): + """Print a debug message to stderr when DEBUG is enabled.""" + if DEBUG: + print >> sys.stderr, msg % args + +def error (msg, *args): + """Print an error message to stderr.""" + print >> sys.stderr, "ERROR:", msg % args + +def warn(msg, *args): + """Print a warning message to stderr.""" + print >> sys.stderr, "warning:", msg % args + +def die (msg, *args): + """Print as error message to stderr and exit the program.""" + error(msg, *args) + sys.exit(1) + + +class ProgressIndicator(object): + + """Simple progress indicator. + + Displayed as a spinning character by default, but can be customized + by passing custom messages that overrides the spinning character. + + """ + + States = ("|", "/", "-", "\\") + + def __init__ (self, prefix = "", f = sys.stdout): + """Create a new ProgressIndicator, bound to the given file object.""" + self.n = 0 # Simple progress counter + self.f = f # Progress is written to this file object + self.prev_len = 0 # Length of previous msg (to be overwritten) + self.prefix = prefix # Prefix prepended to each progress message + self.prefix_lens = [] # Stack of prefix string lengths + + def pushprefix (self, prefix): + """Append the given prefix onto the prefix stack.""" + self.prefix_lens.append(len(self.prefix)) + self.prefix += prefix + + def popprefix (self): + """Remove the last prefix from the prefix stack.""" + prev_len = self.prefix_lens.pop() + self.prefix = self.prefix[:prev_len] + + def __call__ (self, msg = None, lf = False): + """Indicate progress, possibly with a custom message.""" + if msg is None: + msg = self.States[self.n % len(self.States)] + msg = self.prefix + msg + print >> self.f, "\r%-*s" % (self.prev_len, msg), + self.prev_len = len(msg.expandtabs()) + if lf: + print >> self.f + self.prev_len = 0 + self.n += 1 + + def finish (self, msg = "done", noprefix = False): + """Finalize progress indication with the given message.""" + if noprefix: + self.prefix = "" + self(msg, True) + + +def start_command (args, cwd = None, shell = False, add_env = None, + stdin = subprocess.PIPE, stdout = subprocess.PIPE, + stderr = subprocess.PIPE): + """Start the given command, and return a subprocess object. + + This provides a simpler interface to the subprocess module. + + """ + env = None + if add_env is not None: + env = os.environ.copy() + env.update(add_env) + return subprocess.Popen(args, bufsize = 1, stdin = stdin, stdout = stdout, + stderr = stderr, cwd = cwd, shell = shell, + env = env, universal_newlines = True) + + +def run_command (args, cwd = None, shell = False, add_env = None, + flag_error = True): + """Run the given command to completion, and return its results. + + This provides a simpler interface to the subprocess module. + + The results are formatted as a 3-tuple: (exit_code, output, errors) + + If flag_error is enabled, Error messages will be produced if the + subprocess terminated with a non-zero exit code and/or stderr + output. + + The other arguments are passed on to start_command(). + + """ + process = start_command(args, cwd, shell, add_env) + (output, errors) = process.communicate() + exit_code = process.returncode + if flag_error and errors: + error("'%s' returned errors:\n---\n%s---", " ".join(args), errors) + if flag_error and exit_code: + error("'%s' returned exit code %i", " ".join(args), exit_code) + return (exit_code, output, errors) + + +def file_reader_method (missing_ok = False): + """Decorator for simplifying reading of files. + + If missing_ok is True, a failure to open a file for reading will + not raise the usual IOError, but instead the wrapped method will be + called with f == None. The method must in this case properly + handle f == None. + + """ + def _wrap (method): + """Teach given method to handle both filenames and file objects. + + The given method must take a file object as its second argument + (the first argument being 'self', of course). This decorator + will take a filename given as the second argument and promote + it to a file object. + + """ + def _wrapped_method (self, filename, *args, **kwargs): + if isinstance(filename, file): + f = filename + else: + try: + f = open(filename, 'r') + except IOError: + if missing_ok: + f = None + else: + raise + try: + return method(self, f, *args, **kwargs) + finally: + if not isinstance(filename, file) and f: + f.close() + return _wrapped_method + return _wrap + + +def file_writer_method (method): + """Decorator for simplifying writing of files. + + Enables the given method to handle both filenames and file objects. + + The given method must take a file object as its second argument + (the first argument being 'self', of course). This decorator will + take a filename given as the second argument and promote it to a + file object. + + """ + def _new_method (self, filename, *args, **kwargs): + if isinstance(filename, file): + f = filename + else: + # Make sure the containing directory exists + parent_dir = os.path.dirname(filename) + if not os.path.isdir(parent_dir): + os.makedirs(parent_dir) + f = open(filename, 'w') + try: + return method(self, f, *args, **kwargs) + finally: + if not isinstance(filename, file): + f.close() + return _new_method |