Source code for xonsh.tracer

"""Implements a xonsh tracer."""
import os
import re
import sys
import inspect
import argparse
import linecache
import importlib
import functools

from xonsh.lazyasd import LazyObject
from xonsh.platform import HAS_PYGMENTS
from import DefaultNotGiven, print_color, normabspath, to_bool
from xonsh.inspectors import find_file, getouterframes
from xonsh.lazyimps import pygments, pyghooks
from xonsh.proc import STDOUT_CAPTURE_KINDS
import xonsh.prompt.cwd as prompt

terminal = LazyObject(
    lambda: importlib.import_module("pygments.formatters.terminal"),

[docs]class TracerType(object): """Represents a xonsh tracer object, which keeps track of all tracing state. This is a singleton. """ _inst = None valid_events = frozenset(["line", "call"]) def __new__(cls, *args, **kwargs): if cls._inst is None: cls._inst = super(TracerType, cls).__new__(cls, *args, **kwargs) return cls._inst def __init__(self): self.prev_tracer = DefaultNotGiven self.files = set() self.usecolor = True self.lexer = pyghooks.XonshLexer() self.formatter = terminal.TerminalFormatter() self._last = ("", -1) # filename, lineno tuple def __del__(self): for f in set(self.files): self.stop(f)
[docs] def color_output(self, usecolor): """Specify whether or not the tracer output should be colored.""" # we have to use a function to set usecolor because of the way that # lazyasd works. Namely, it cannot dispatch setattr to the target # object without being unable to access its own __dict__. This makes # setting an attr look like getting a function. self.usecolor = usecolor
[docs] def start(self, filename): """Starts tracing a file.""" files = self.files if len(files) == 0: self.prev_tracer = sys.gettrace() files.add(normabspath(filename)) sys.settrace(self.trace) curr = inspect.currentframe() for frame, fname, *_ in getouterframes(curr, context=0): if normabspath(fname) in files: frame.f_trace = self.trace
[docs] def stop(self, filename): """Stops tracing a file.""" filename = normabspath(filename) self.files.discard(filename) if len(self.files) == 0: sys.settrace(self.prev_tracer) curr = inspect.currentframe() for frame, fname, *_ in getouterframes(curr, context=0): if normabspath(fname) == filename: frame.f_trace = self.prev_tracer self.prev_tracer = DefaultNotGiven
[docs] def trace(self, frame, event, arg): """Implements a line tracing function.""" if event not in self.valid_events: return self.trace fname = find_file(frame) if fname in self.files: lineno = frame.f_lineno curr = (fname, lineno) if curr != self._last: line = linecache.getline(fname, lineno).rstrip() s = tracer_format_line( fname, lineno, line, color=self.usecolor, lexer=self.lexer, formatter=self.formatter, ) print_color(s) self._last = curr return self.trace
tracer = LazyObject(TracerType, globals(), "tracer") COLORLESS_LINE = "{fname}:{lineno}:{line}" COLOR_LINE = "{{PURPLE}}{fname}{{BLUE}}:" "{{GREEN}}{lineno}{{BLUE}}:" "{{NO_COLOR}}"
[docs]def tracer_format_line(fname, lineno, line, color=True, lexer=None, formatter=None): """Formats a trace line suitable for printing.""" fname = min(fname, prompt._replace_home(fname), os.path.relpath(fname), key=len) if not color: return COLORLESS_LINE.format(fname=fname, lineno=lineno, line=line) cline = COLOR_LINE.format(fname=fname, lineno=lineno) if not HAS_PYGMENTS: return cline + line # OK, so we have pygments tokens = pyghooks.partial_color_tokenize(cline) lexer = lexer or pyghooks.XonshLexer() tokens += pygments.lex(line, lexer=lexer) if tokens[-1][1] == "\n": del tokens[-1] elif tokens[-1][1].endswith("\n"): tokens[-1] = (tokens[-1][0], tokens[-1][1].rstrip()) return tokens
# # Command line interface # def _find_caller(args): """Somewhat hacky method of finding the __file__ based on the line executed.""" re_line = re.compile(r"[^;\s|&<>]+\s+" + r"\s+".join(args)) curr = inspect.currentframe() for _, fname, lineno, _, lines, _ in getouterframes(curr, context=1)[3:]: if lines is not None and[0]) is not None: return fname elif ( lineno == 1 and, lineno)) is not None ): # There is a bug in CPython such that getouterframes(curr, context=1) # will actually return the 2nd line in the code_context field, even though # line number is itself correct. We manually fix that in this branch. return fname else: msg = ( "xonsh: warning: __file__ name could not be found. You may be " "trying to trace interactively. Please pass in the file names " "you want to trace explicitly." ) print(msg, file=sys.stderr) def _on(ns, args): """Turns on tracing for files.""" for f in ns.files: if f == "__file__": f = _find_caller(args) if f is None: continue tracer.start(f) def _off(ns, args): """Turns off tracing for files.""" for f in ns.files: if f == "__file__": f = _find_caller(args) if f is None: continue tracer.stop(f) def _color(ns, args): """Manages color action for tracer CLI.""" tracer.color_output(ns.toggle) @functools.lru_cache(1) def _tracer_create_parser(): """Creates tracer argument parser""" p = argparse.ArgumentParser( prog="trace", description="tool for tracing xonsh code as it runs." ) subp = p.add_subparsers(title="action", dest="action") onp = subp.add_parser( "on", aliases=["start", "add"], help="begins tracing selected files." ) onp.add_argument( "files", nargs="*", default=["__file__"], help=( 'file paths to watch, use "__file__" (default) to select ' "the current file." ), ) off = subp.add_parser( "off", aliases=["stop", "del", "rm"], help="removes selected files fom tracing." ) off.add_argument( "files", nargs="*", default=["__file__"], help=( 'file paths to stop watching, use "__file__" (default) to ' "select the current file." ), ) col = subp.add_parser("color", help="output color management for tracer.") col.add_argument( "toggle", type=to_bool, help="true/false, y/n, etc. to toggle color usage." ) return p _TRACER_MAIN_ACTIONS = { "on": _on, "add": _on, "start": _on, "rm": _off, "off": _off, "del": _off, "stop": _off, "color": _color, }
[docs]def tracermain(args=None, stdin=None, stdout=None, stderr=None, spec=None): """Main function for tracer command-line interface.""" parser = _tracer_create_parser() ns = parser.parse_args(args) usecolor = (spec.captured not in STDOUT_CAPTURE_KINDS) and sys.stdout.isatty() tracer.color_output(usecolor) return _TRACER_MAIN_ACTIONS[ns.action](ns, args)