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# -*- coding: utf-8 -*-
"""Implements JSON version of xonsh history backend."""
import os
import sys
import time
import json
import builtins
import collections
import threading
import collections.abc as cabc
from xonsh.history.base import History
import xonsh.tools as xt
import xonsh.lazyjson as xlj
import xonsh.xoreutils.uptime as uptime
def _xhj_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 _xhj_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 _xhj_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 _xhj_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
def _xhj_get_history_files(sort=True, newest_first=False):
"""Find and return the history files. Optionally sort files by
modify time.
"""
data_dir = builtins.__xonsh__.env.get("XONSH_DATA_DIR")
data_dir = xt.expanduser_abs_path(data_dir)
try:
files = [
os.path.join(data_dir, f)
for f in os.listdir(data_dir)
if f.startswith("xonsh-") and f.endswith(".json")
]
except OSError:
files = []
if builtins.__xonsh__.env.get("XONSH_DEBUG"):
xt.print_exception("Could not collect xonsh history files.")
if sort:
files.sort(key=lambda x: os.path.getmtime(x), reverse=newest_first)
return files
class JsonHistoryGC(threading.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 for 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.gc_units_to_rmfiles = {
"commands": _xhj_gc_commands_to_rmfiles,
"files": _xhj_gc_files_to_rmfiles,
"s": _xhj_gc_seconds_to_rmfiles,
"b": _xhj_gc_bytes_to_rmfiles,
}
self.start()
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 = xt.to_history_tuple(self.size)
files = self.files(only_unlocked=True)
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 files(self, only_unlocked=False):
"""Find and return the history files. Optionally locked files may be
excluded.
This is sorted by the last closed time. Returns a list of
(timestamp, number of cmds, file name) tuples.
"""
# pylint: disable=no-member
env = getattr(builtins, "__xonsh__.env", None)
if env is None:
return []
boot = uptime.boottime()
fs = _xhj_get_history_files(sort=False)
files = []
for f in fs:
try:
if os.path.getsize(f) == 0:
# collect empty files (for gc)
files.append((time.time(), 0, f))
continue
lj = xlj.LazyJSON(f, reopen=False)
if lj["locked"] and lj["ts"][0] < boot:
# computer was rebooted between when this history was created
# and now and so this history should be unlocked.
hist = lj.load()
lj.close()
hist["locked"] = False
with open(f, "w", newline="\n") as fp:
xlj.ljdump(hist, fp, sort_keys=True)
lj = xlj.LazyJSON(f, reopen=False)
if only_unlocked and lj["locked"]:
continue
# info: closing timestamp, number of commands, filename
files.append((lj["ts"][1] or lj["ts"][0], len(lj.sizes["cmds"]) - 1, f))
lj.close()
except (IOError, OSError, ValueError):
continue
files.sort()
return files
class JsonHistoryFlusher(threading.Thread):
"""Flush shell history to disk periodically."""
def __init__(self, filename, buffer, queue, cond, at_exit=False, *args, **kwargs):
"""Thread for flushing history."""
super(JsonHistoryFlusher, 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."""
opts = builtins.__xonsh__.env.get("HISTCONTROL")
last_inp = None
cmds = []
for cmd in self.buffer:
if "ignoredups" in opts and cmd["inp"] == last_inp:
# Skipping dup cmd
continue
if "ignoreerr" in opts and cmd["rtn"] != 0:
# Skipping failed cmd
continue
cmds.append(cmd)
last_inp = cmd["inp"]
with open(self.filename, "r", newline="\n") as f:
hist = xlj.LazyJSON(f).load()
load_hist_len = len(hist["cmds"])
hist["cmds"].extend(cmds)
if self.at_exit:
hist["ts"][1] = time.time() # apply end time
hist["locked"] = False
if not builtins.__xonsh__.env.get("XONSH_STORE_STDOUT", False):
[cmd.pop("out") for cmd in hist["cmds"][load_hist_len:] if "out" in cmd]
with open(self.filename, "w", newline="\n") as f:
xlj.ljdump(hist, f, sort_keys=True)
class JsonCommandField(cabc.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("JsonCommandField may only be indexed by int or slice.")
elif size == 0:
raise IndexError("JsonCommandField 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 = xlj.LazyJSON(f, reopen=False)
rtn = lj["cmds"][key].get(self.field, self.default)
if isinstance(rtn, xlj.LJNode):
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 JsonHistory(History):
"""Xonsh history backend implemented with JSON files.
JsonHistory implements two extra actions: ``diff``, and ``replay``.
"""
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.
"""
super().__init__(sessionid=sessionid, **meta)
if filename is None:
# pylint: disable=no-member
data_dir = builtins.__xonsh__.env.get("XONSH_DATA_DIR")
data_dir = os.path.expanduser(data_dir)
self.filename = os.path.join(
data_dir, "xonsh-{0}.json".format(self.sessionid)
)
else:
self.filename = filename
self.buffer = []
self.buffersize = buffersize
self._queue = collections.deque()
self._cond = threading.Condition()
self._len = 0
self.last_cmd_out = None
self.last_cmd_rtn = None
meta["cmds"] = []
meta["sessionid"] = str(self.sessionid)
with open(self.filename, "w", newline="\n") as f:
xlj.ljdump(meta, f, sort_keys=True)
self.gc = JsonHistoryGC() if gc else None
# command fields that are known
self.tss = JsonCommandField("ts", self)
self.inps = JsonCommandField("inp", self)
self.outs = JsonCommandField("out", self)
self.rtns = JsonCommandField("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
This dict contains information about the command that is to be
added to the history list. It should contain the keys ``inp``,
``rtn`` and ``ts``. These key names mirror the same names defined
as instance variables in the ``HistoryEntry`` class.
Returns
-------
hf : JsonHistoryFlusher or None
The thread that was spawned to flush history
"""
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 JsonHistoryFlusher should act as a thread in the
background, or execute immediately and block.
Returns
-------
hf : JsonHistoryFlusher or None
The thread that was spawned to flush history
"""
if len(self.buffer) == 0:
return
hf = JsonHistoryFlusher(
self.filename, tuple(self.buffer), self._queue, self._cond, at_exit=at_exit
)
self.buffer.clear()
return hf
def items(self, newest_first=False):
"""Display history items of current session."""
if newest_first:
items = zip(reversed(self.inps), reversed(self.tss))
else:
items = zip(self.inps, self.tss)
for item, tss in items:
yield {"inp": item.rstrip(), "ts": tss[0]}
def all_items(self, newest_first=False, **kwargs):
"""
Returns all history as found in XONSH_DATA_DIR.
yield format: {'inp': cmd, 'rtn': 0, ...}
"""
while self.gc and self.gc.is_alive():
time.sleep(0.011) # gc sleeps for 0.01 secs, sleep a beat longer
for f in _xhj_get_history_files(newest_first=newest_first):
try:
json_file = xlj.LazyJSON(f, reopen=False)
except ValueError:
# Invalid json file
continue
try:
commands = json_file.load()["cmds"]
except json.decoder.JSONDecodeError:
# file is corrupted somehow
if builtins.__xonsh__.env.get("XONSH_DEBUG") > 0:
msg = "xonsh history file {0!r} is not valid JSON"
print(msg.format(f), file=sys.stderr)
continue
if newest_first:
commands = reversed(commands)
for c in commands:
yield {"inp": c["inp"].rstrip(), "ts": c["ts"][0]}
# all items should also include session items
yield from self.items()
def info(self):
data = collections.OrderedDict()
data["backend"] = "json"
data["sessionid"] = str(self.sessionid)
data["filename"] = self.filename
data["length"] = len(self)
data["buffersize"] = self.buffersize
data["bufferlength"] = len(self.buffer)
envs = builtins.__xonsh__.env
data["gc options"] = envs.get("XONSH_HISTORY_SIZE")
return data
def run_gc(self, size=None, blocking=True):
self.gc = JsonHistoryGC(wait_for_shell=False, size=size)
if blocking:
while self.gc.is_alive():
continue
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