path: root/ranger/ext/rifle.py

#!/usr/bin/python
# This file is part of ranger, the console file manager.
# License: GNU GPL version 3, see the file "AUTHORS" for details.

"""rifle, the file executor/opener of ranger

This can be used as a standalone program or can be embedded in python code.
When used together with ranger, it doesn't have to be installed to $PATH.

Example usage:

    rifle = Rifle("rifle.conf")
    rifle.reload_config()
    rifle.execute(["file1", "file2"])
"""

from __future__ import (absolute_import, division, print_function)

import os.path
import re
from subprocess import Popen, PIPE
import sys

__version__ = 'rifle 1.9.0b5'

# Options and constants that a user might want to change:
DEFAULT_PAGER = 'less'
DEFAULT_EDITOR = 'vim'
ASK_COMMAND = 'ask'
ENCODING = 'utf-8'

# Imports from ranger library, plus reimplementations in case ranger is not
# installed so rifle can be run as a standalone program.
try:
    from ranger.ext.get_executables import get_executables
except ImportError:
    _CACHED_EXECUTABLES = None

    def get_executables():
        """Return all executable files in $PATH + Cache them."""
        global _CACHED_EXECUTABLES  # pylint: disable=global-statement
        if _CACHED_EXECUTABLES is not None:
            return _CACHED_EXECUTABLES

        if 'PATH' in os.environ:
            paths = os.environ['PATH'].split(':')
        else:
            paths = ['/usr/bin', '/bin']

        from stat import S_IXOTH, S_IFREG
        paths_seen = set()
        _CACHED_EXECUTABLES = set()
        for path in paths:
            if path in paths_seen:
                continue
            paths_seen.add(path)
            try:
                content = os.listdir(path)
            except OSError:
                continue
            for item in content:
                abspath = path + '/' + item
                try:
                    filestat = os.stat(abspath)
                except OSError:
                    continue
                if filestat.st_mode & (S_IXOTH | S_IFREG):
                    _CACHED_EXECUTABLES.add(item)
        return _CACHED_EXECUTABLES


try:
    from ranger.ext.popen_forked import Popen_forked
except ImportError:
    def Popen_forked(*args, **kwargs):  # pylint: disable=invalid-name
        """Forks process and runs Popen with the given args and kwargs."""
        try:
            pid = os.fork()
        except OSError:
            return False
        if pid == 0:
            os.setsid()
            kwargs['stdin'] = open(os.devnull, 'r')
            kwargs['stdout'] = kwargs['stderr'] = open(os.devnull, 'w')
            Popen(*args, **kwargs)
            os._exit(0)  # pylint: disable=protected-access
        return True


def _is_terminal():
    # Check if stdin (file descriptor 0), stdout (fd 1) and
    # stderr (fd 2) are connected to a terminal
    try:
        os.ttyname(0)
        os.ttyname(1)
        os.ttyname(2)
    except OSError:
        return False
    return True


def squash_flags(flags):
    """Remove lowercase flags if the respective uppercase flag exists

    >>> squash_flags('abc')
    'abc'
    >>> squash_flags('abcC')
    'ab'
    >>> squash_flags('CabcAd')
    'bd'
    """
    exclude = ''.join(f.upper() + f.lower() for f in flags if f == f.upper())
    return ''.join(f for f in flags if f not in exclude)


class Rifle(object):  # pylint: disable=too-many-instance-attributes
    delimiter1 = '='
    delimiter2 = ','

    # TODO: Test all of the hooks properly
    def hook_before_executing(self, command, mimetype, flags):
        pass

    def hook_after_executing(self, command, mimetype, flags):
        pass

    @staticmethod
    def hook_command_preprocessing(command):
        return command

    @staticmethod
    def hook_command_postprocessing(command):
        return command

    @staticmethod
    def hook_environment(env):
        return env

    @staticmethod
    def hook_logger(string):
        sys.stderr.write(string + "\n")

    def __init__(self, config_file):
        self.config_file = config_file
        self._app_flags = ''
        self._app_label = None
        self._initialized_mimetypes = False
        self._mimetype = None
        self._skip = None
        self.rules = None

        # get paths for mimetype files
        self._mimetype_known_files = [os.path.expanduser("~/.mime.types")]
        if __file__.endswith("ranger/ext/rifle.py"):
            # Add ranger's default mimetypes when run from ranger directory
            self._mimetype_known_files.append(
                __file__.replace("ext/rifle.py", "data/mime.types"))

    def reload_config(self, config_file=None):
        """Replace the current configuration with the one in config_file"""
        if config_file is None:
            config_file = self.config_file
        fobj = open(config_file, 'r')
        self.rules = []
        lineno = 0
        for line in fobj:
            lineno += 1
            line = line.strip()
            if line.startswith('#') or line == '':
                continue
            if self.delimiter1 not in line:
                raise ValueError("Line without delimiter")
            tests, command = line.split(self.delimiter1, 1)
            tests = tests.split(self.delimiter2)
            tests = tuple(tuple(f.strip().split(None, 1)) for f in tests)
            command = command.strip()
            self.rules.append((command, tests))
        fobj.close()

    def _eval_condition(self, condition, files, label):
        # Handle the negation of conditions starting with an exclamation mark,
        # then pass on the arguments to _eval_condition2().

        if not condition:
            return True
        if condition[0].startswith('!'):
            new_condition = tuple([condition[0][1:]]) + tuple(condition[1:])
            return not self._eval_condition2(new_condition, files, label)
        return self._eval_condition2(condition, files, label)

    def _eval_condition2(  # pylint: disable=too-many-return-statements,too-many-branches
            self, rule, files, label):
        # This function evaluates the condition, after _eval_condition() handled
        # negation of conditions starting with a "!".

        if not files:
            return False

        function = rule[0]
        argument = rule[1] if len(rule) > 1 else ''

        if function == 'ext':
            if os.path.isfile(files[0]):
                partitions = os.path.basename(files[0]).rpartition('.')
                if not partitions[0]:
                    return False
                return bool(re.search('^(' + argument + ')$', partitions[2].lower()))
        elif function == 'name':
            return bool(re.search(argument, os.path.basename(files[0])))
        elif function == 'match':
            return bool(re.search(argument, files[0]))
        elif function == 'file':
            return os.path.isfile(files[0])
        elif function == 'directory':
            return os.path.isdir(files[0])
        elif function == 'path':
            return bool(re.search(argument, os.path.abspath(files[0])))
        elif function == 'mime':
            return bool(re.search(argument, self.get_mimetype(files[0])))
        elif function == 'has':
            if argument.startswith("$"):
                if argument[1:] in os.environ:
                    return os.environ[argument[1:]] in get_executables()
                return False
            else:
                return argument in get_executables()
        elif function == 'terminal':
            return _is_terminal()
        elif function == 'number':
            if argument.isdigit():
                self._skip = int(argument)
            return True
        elif function == 'label':
            self._app_label = argument
            if label:
                return argument == label
            return True
        elif function == 'flag':
            self._app_flags = argument
            return True
        elif function == 'X':
            return sys.platform == 'darwin' or 'DISPLAY' in os.environ
        elif function == 'env':
            return bool(os.environ.get(argument))
        elif function == 'else':
            return True

    def get_mimetype(self, fname):
        # Spawn "file" to determine the mime-type of the given file.
        if self._mimetype:
            return self._mimetype

        import mimetypes
        for path in self._mimetype_known_files:
            if path not in mimetypes.knownfiles:
                mimetypes.knownfiles.append(path)
        self._mimetype, _ = mimetypes.guess_type(fname)

        if not self._mimetype:
            process = Popen(["file", "--mime-type", "-Lb", fname], stdout=PIPE, stderr=PIPE)
            mimetype, _ = process.communicate()
            self._mimetype = mimetype.decode(ENCODING).strip()
        return self._mimetype

    def _build_command(self, files, action, flags):
        # Get the flags
        if isinstance(flags, str):
            self._app_flags += flags
        self._app_flags = squash_flags(self._app_flags)
        filenames = "' '".join(f.replace("'", "'\\\''") for f in files if "\x00" not in f)
        return "set -- '%s