xonsh/xonsh/history.py
2016-02-05 01:25:59 -05:00

456 lines
15 KiB
Python

# -*- coding: utf-8 -*-
"""Implements the xonsh history object."""
import argparse
import functools
import os
import uuid
import time
import builtins
from glob import iglob
from collections import deque, Sequence, OrderedDict
from threading import Thread, Condition
from xonsh import lazyjson
from xonsh.tools import ensure_int_or_slice, to_history_tuple
from xonsh import diff_history
def _gc_commands_to_rmfiles(hsize, files):
"""Return the history files to remove to get under the command limit."""
rmfiles = []
n = 0
ncmds = 0
for ts, fcmds, f in files[::-1]:
if fcmds == 0:
# we need to make sure that 'empty' history files don't hang around
rmfiles.append((ts, fcmds, f))
if ncmds + fcmds > hsize:
break
ncmds += fcmds
n += 1
rmfiles += files[:-n]
return rmfiles
def _gc_files_to_rmfiles(hsize, files):
"""Return the history files to remove to get under the file limit."""
rmfiles = files[:-hsize] if len(files) > hsize else []
return rmfiles
def _gc_seconds_to_rmfiles(hsize, files):
"""Return the history files to remove to get under the age limit."""
rmfiles = []
now = time.time()
for ts, _, f in files:
if (now - ts) < hsize:
break
rmfiles.append((None, None, f))
return rmfiles
def _gc_bytes_to_rmfiles(hsize, files):
"""Return the history files to remove to get under the byte limit."""
rmfiles = []
n = 0
nbytes = 0
for _, _, f in files[::-1]:
fsize = os.stat(f).st_size
if nbytes + fsize > hsize:
break
nbytes += fsize
n += 1
rmfiles = files[:-n]
return rmfiles
class HistoryGC(Thread):
"""Shell history garbage collection."""
def __init__(self, wait_for_shell=True, size=None, *args, **kwargs):
"""Thread responsible for garbage collecting old history.
May wait for shell (and thus xonshrc to have been loaded) to start work.
"""
super().__init__(*args, **kwargs)
self.daemon = True
self.size = size
self.wait_for_shell = wait_for_shell
self.start()
self.gc_units_to_rmfiles = {'commands': _gc_commands_to_rmfiles,
'files': _gc_files_to_rmfiles,
's': _gc_seconds_to_rmfiles,
'b': _gc_bytes_to_rmfiles}
def run(self):
while self.wait_for_shell:
time.sleep(0.01)
env = builtins.__xonsh_env__ # pylint: disable=no-member
if self.size is None:
hsize, units = env.get('XONSH_HISTORY_SIZE')
else:
hsize, units = to_history_tuple(self.size)
files = self.unlocked_files()
rmfiles_fn = self.gc_units_to_rmfiles.get(units)
if rmfiles_fn is None:
raise ValueError('Units type {0!r} not understood'.format(units))
for _, _, f in rmfiles_fn(hsize, files):
try:
os.remove(f)
except OSError:
pass
def unlocked_files(self):
"""Find and return the history files that are unlocked.
This is sorted by the last closed time. Returns a list of (timestamp,
file) tuples.
"""
_ = self # this could be a function but is intimate to this class
# pylint: disable=no-member
xdd = os.path.abspath(builtins.__xonsh_env__.get('XONSH_DATA_DIR'))
fs = [f for f in iglob(os.path.join(xdd, 'xonsh-*.json'))]
files = []
for f in fs:
try:
lj = lazyjson.LazyJSON(f, reopen=False)
if lj['locked']:
continue
# info: closing timestamp, number of commands, filename
files.append((lj['ts'][1], len(lj.sizes['cmds']) - 1, f))
lj.close()
except (IOError, OSError, ValueError):
continue
files.sort()
return files
class HistoryFlusher(Thread):
"""Flush shell history to disk periodically."""
def __init__(self, filename, buffer, queue, cond, at_exit=False, *args,
**kwargs):
"""Thread for flushing history."""
super(HistoryFlusher, self).__init__(*args, **kwargs)
self.filename = filename
self.buffer = buffer
self.queue = queue
queue.append(self)
self.cond = cond
self.at_exit = at_exit
if at_exit:
self.dump()
queue.popleft()
else:
self.start()
def run(self):
with self.cond:
self.cond.wait_for(self.i_am_at_the_front)
self.dump()
self.queue.popleft()
def i_am_at_the_front(self):
"""Tests if the flusher is at the front of the queue."""
return self is self.queue[0]
def dump(self):
"""Write the cached history to external storage."""
with open(self.filename, 'r', newline='\n') as f:
hist = lazyjson.LazyJSON(f).load()
hist['cmds'].extend(self.buffer)
if self.at_exit:
hist['ts'][1] = time.time() # apply end time
hist['locked'] = False
with open(self.filename, 'w', newline='\n') as f:
lazyjson.dump(hist, f, sort_keys=True)
class CommandField(Sequence):
"""A field in the 'cmds' portion of history."""
def __init__(self, field, hist, default=None):
"""Represents a field in the 'cmds' portion of history.
Will query the buffer for the relevant data, if possible. Otherwise it
will lazily acquire data from the file.
Parameters
----------
field : str
The name of the field to query.
hist : History object
The history object to query.
default : optional
The default value to return if key is not present.
"""
self.field = field
self.hist = hist
self.default = default
def __len__(self):
return len(self.hist)
def __getitem__(self, key):
size = len(self)
if isinstance(key, slice):
return [self[i] for i in range(*key.indices(size))]
elif not isinstance(key, int):
raise IndexError(
'CommandField may only be indexed by int or slice.')
elif size == 0:
raise IndexError('CommandField is empty.')
# now we know we have an int
key = size + key if key < 0 else key # ensure key is non-negative
bufsize = len(self.hist.buffer)
if size - bufsize <= key: # key is in buffer
return self.hist.buffer[key + bufsize - size].get(
self.field, self.default)
# now we know we have to go into the file
queue = self.hist._queue
queue.append(self)
with self.hist._cond:
self.hist._cond.wait_for(self.i_am_at_the_front)
with open(self.hist.filename, 'r', newline='\n') as f:
lj = lazyjson.LazyJSON(f, reopen=False)
rtn = lj['cmds'][key].get(self.field, self.default)
if isinstance(rtn, lazyjson.Node):
rtn = rtn.load()
queue.popleft()
return rtn
def i_am_at_the_front(self):
"""Tests if the command field is at the front of the queue."""
return self is self.hist._queue[0]
class History(object):
"""Xonsh session history."""
def __init__(self, filename=None, sessionid=None, buffersize=100, gc=True,
**meta):
"""Represents a xonsh session's history as an in-memory buffer that is
periodically flushed to disk.
Parameters
----------
filename : str, optional
Location of history file, defaults to
``$XONSH_DATA_DIR/xonsh-{sessionid}.json``.
sessionid : int, uuid, str, optional
Current session identifier, will generate a new sessionid if not
set.
buffersize : int, optional
Maximum buffersize in memory.
meta : optional
Top-level metadata to store along with the history. The kwargs
'cmds' and 'sessionid' are not allowed and will be overwritten.
gc : bool, optional
Run garbage collector flag.
"""
self.sessionid = sid = uuid.uuid4() if sessionid is None else sessionid
if filename is None:
# pylint: disable=no-member
data_dir = builtins.__xonsh_env__.get('XONSH_DATA_DIR')
self.filename = os.path.join(data_dir, 'xonsh-{0}.json'.format(sid))
else:
self.filename = filename
self.buffer = []
self.buffersize = buffersize
self._queue = deque()
self._cond = Condition()
self._len = 0
self.last_cmd_out = None
self.last_cmd_rtn = None
meta['cmds'] = []
meta['sessionid'] = str(sid)
with open(self.filename, 'w', newline='\n') as f:
lazyjson.dump(meta, f, sort_keys=True)
self.gc = HistoryGC() if gc else None
# command fields that are known
self.tss = CommandField('ts', self)
self.inps = CommandField('inp', self)
self.outs = CommandField('out', self)
self.rtns = CommandField('rtn', self)
def __len__(self):
return self._len
def append(self, cmd):
"""Appends command to history. Will periodically flush the history to file.
Parameters
----------
cmd : dict
Command dictionary that should be added to the ordered history.
Returns
-------
hf : HistoryFlusher or None
The thread that was spawned to flush history
"""
opts = builtins.__xonsh_env__.get('HISTCONTROL')
if ('ignoredups' in opts and len(self) > 0
and cmd['inp'] == self.inps[-1]):
# Skipping dup cmd
return None
elif 'ignoreerr' in opts and cmd['rtn'] != 0:
# Skipping failed cmd
return None
self.buffer.append(cmd)
self._len += 1 # must come before flushing
if len(self.buffer) >= self.buffersize:
hf = self.flush()
else:
hf = None
return hf
def flush(self, at_exit=False):
"""Flushes the current command buffer to disk.
Parameters
----------
at_exit : bool, optional
Whether the HistoryFlusher should act as a thread in the background,
or execute immeadiately and block.
Returns
-------
hf : HistoryFlusher or None
The thread that was spawned to flush history
"""
if len(self.buffer) == 0:
return
hf = HistoryFlusher(self.filename, tuple(self.buffer), self._queue,
self._cond, at_exit=at_exit)
self.buffer.clear()
return hf
#
# Interface to History
#
@functools.lru_cache()
def _create_parser():
"""Create a parser for the "history" command."""
p = argparse.ArgumentParser(prog='history',
description='Tools for dealing with history')
subp = p.add_subparsers(title='action', dest='action')
# show action
show = subp.add_parser('show',
help='displays current history, default action')
show.add_argument('-r', dest='reverse', default=False, action='store_true',
help='reverses the direction')
show.add_argument('n', nargs='?', default=None,
help='display n\'th history entry if n is a simple int, '
'or range of entries if it is Python slice notation')
# 'id' subcommand
subp.add_parser('id', help='displays the current session id')
# 'file' subcommand
subp.add_parser('file', help='displays the current history filename')
# 'info' subcommand
info = subp.add_parser('info', help=('displays information about the '
'current history'))
info.add_argument('--json', dest='json', default=False, action='store_true',
help='print in JSON format')
# diff
diff = subp.add_parser('diff', help='diffs two xonsh history files')
diff_history._create_parser(p=diff)
# replay, dynamically
from xonsh import replay
rp = subp.add_parser('replay', help='replays a xonsh history file')
replay._create_parser(p=rp)
_MAIN_ACTIONS['replay'] = replay._main_action
# gc
gcp = subp.add_parser('gc', help='launches a new history garbage collector')
gcp.add_argument('--size', nargs=2, dest='size', default=None,
help=('next two arguments represent the history size and '
'units; e.g. "--size 8128 commands"'))
bgcp = gcp.add_mutually_exclusive_group()
bgcp.add_argument('--blocking', dest='blocking', default=True,
action='store_true',
help=('ensures that the gc blocks the main thread, '
'default True'))
bgcp.add_argument('--non-blocking', dest='blocking', action='store_false',
help='makes the gc non-blocking, and thus return sooner')
return p
def _show(ns, hist):
"""Show the requested portion of the shell history."""
idx = ensure_int_or_slice(ns.n)
if len(hist) == 0:
return
inps = hist.inps[idx]
if isinstance(idx, int):
inps = [inps]
indices = [idx if idx >= 0 else len(hist) + idx]
else:
indices = list(range(*idx.indices(len(hist))))
ndigits = len(str(indices[-1]))
indent = ' '*(ndigits + 3)
if ns.reverse:
indices = reversed(indices)
inps = reversed(inps)
for i, inp in zip(indices, inps):
lines = inp.splitlines()
lines[0] = ' {0:>{1}} {2}'.format(i, ndigits, lines[0])
lines[1:] = [indent + x for x in lines[1:]]
print('\n'.join(lines))
def _info(ns, hist):
"""Display information about the shell history."""
data = OrderedDict()
data['sessionid'] = str(hist.sessionid)
data['filename'] = hist.filename
data['length'] = len(hist)
data['buffersize'] = hist.buffersize
data['bufferlength'] = len(hist.buffer)
if ns.json:
import json
s = json.dumps(data)
print(s)
else:
lines = ['{0}: {1}'.format(k, v) for k, v in data.items()]
print('\n'.join(lines))
def _gc(ns, hist):
"""Start and monitor garbage collection of the shell history."""
hist.gc = gc = HistoryGC(wait_for_shell=False, size=ns.size)
if ns.blocking:
while gc.is_alive():
continue
_MAIN_ACTIONS = {
'show': _show,
'id': lambda ns, hist: print(hist.sessionid),
'file': lambda ns, hist: print(hist.filename),
'info': _info,
'diff': diff_history._main_action,
'gc': _gc,
}
def _main(hist, args):
"""This implements the history CLI."""
if not args or (args[0] not in _MAIN_ACTIONS and
args[0] not in {'-h', '--help'}):
args.insert(0, 'show')
if (args[0] == 'show' and len(args) > 1 and args[-1].startswith('-') and
args[-1][1].isdigit()):
args.insert(-1, '--') # ensure parsing stops before a negative int
ns = _create_parser().parse_args(args)
if ns.action is None: # apply default action
ns = _create_parser().parse_args(['show'] + args)
_MAIN_ACTIONS[ns.action](ns, hist)
def main(args=None, stdin=None):
"""This is the history command entry point."""
_ = stdin
_main(builtins.__xonsh_history__, args) # pylint: disable=no-member