Remember what files are opened in a session of gedit

#!/usr/bin/env python
# -*- coding: utf-8 -*-

'''

REQUIRES:

   sudo apt install xdotool
'''
    
from __future__ import print_function           # Must be first import
import os
import time

OTHERS_TIME = 3                                 # Firefox, etc. to load up
SERVER_TIME = 1.5                               # gnome-terminal-server time
BASHRC_TIME = 1.5                               # Seconds to load ~/.bashrc
WINDOW_TIME = .5                                # Seconds fpr window to appear

def launch_command(ext_name):
    ''' Launch external command in background and return PID to parent.
        Use for programs requiring more than .2 seconds to run.
    '''

    all_pids = get_pids(ext_name)       # Snapshot current PID list
    all_wins = get_wins(all_pids)       # Snapshot of windows open
    new_pids = all_pids
    new_wins = all_wins
    sleep_count = 0                     # Counter to prevent infinite loops

    os.popen(ext_name)                  # Run command in background

    while new_pids == all_pids:         # Loop until new PID is assigned
        new_pids = get_pids(ext_name)   # Snapshot current PID list
        if sleep_count > 0:             # Don't sleep first time through loop
            time.sleep(.005)            # sleep 5 milliseconds
        sleep_count += 1
        if sleep_count == 1000:         # 10 second time-out
            print('launch_ext_command() ERROR: max sleep count reached')
            print('External command name:',ext_name)
            return 0, 0

    pid_list = list(set(new_pids) - set(all_pids))
    if not len(pid_list) == 1:
        print('launch_command() ERROR: A new PID could not be found')
        return 0, 0

    time.sleep(WINDOW_TIME)             # Give time for window to appear
    new_wins = get_wins(all_pids)       # Snapshot of windows open
    win_list = list(set(new_wins) - set(all_wins))
    if not len(win_list) == 1:
        #print('launch_command() ERROR: New Window ID could not be found')
        #suppress error message because we aren't using window ID at all
        return int(pid_list[0]), 0

    # Return PID of program we just launched in background
    return int(pid_list[0]), int(win_list[0])


def get_pids(ext_name):
    ''' Return list of PIDs for program name and arguments
        Whitespace output is compressed to single space
    '''
    all_lines = []
    # Just grep up to first space in command line. It was failing on !
    prog_name = ext_name.split(' ',1)[0]
    all_lines = os.popen("ps aux | grep -v grep | grep " + \
                        "'" + prog_name + "'").read().strip().splitlines
    PID = []
    for l in all_lines():
        l = ' '.join(l.split())         # Compress whitespace into single space
        PID.append(int(l.split(' ', 2)[1]))

    return PID


def get_wins(all_pids):
    ''' Return list of all windows open under PID list
        Currently unnecessary because we work on active window '''
    windows = []
    for pid in all_pids:
        all_lines = os.popen('xdotool search --pid ' + str(pid)). \
                             read().strip().splitlines
        for l in all_lines():
            windows.append(int(l))

    return windows



def gedit():

    last_modified_files = gedit_recent_files()
    command = 'gedit '
    for f in last_modified_files:
        # Add each file name to parameter list passed to `gedit`
        command += '"' + f + '" '

    # Open gedit with last five modfied files. '&' = run in background
    command=command+' &'
    active_pid, active_win = launch_command(command)
    if active_pid == 0:
        print("ERROR launching", command, \
        "Aborting 'alienstart' script")
        exit()


def gedit_recent_files():
    ''' Get list of gedit 5 most recent files:
    
grep --no-group-separator -B5 'group>gedit' ~/.local/share/recently-used.xbel | sed -n 1~6p | sed 's#  <bookmark href="file:///#/#g' | sed 's/"//g'

/home/rick/python/mmm added=2020-05-02T15:34:55Z modified=2020-11-19T00:43:45Z visited=2020-05-02T15:34:56Z>
/home/rick/python/mserve added=2020-07-26T16:36:09Z modified=2020-11-28T01:57:19Z visited=2020-07-26T16:36:09Z>

    '''
    command = "grep --no-group-separator -B5 'group>gedit' " + \
              "~/.local/share/recently-used.xbel | " + \
              "sed -n 1~6p | sed 's#  <bookmark href=" + '"' + \
              "file:///#/#g' | " + "sed 's/" + '"' + "//g'"

    recent_files = []
    times = []
    all_lines = os.popen(command).read().strip().splitlines
    uniquifier = 1                  # gedit can give all open files same time
    for l in all_lines():
        fname = l.split(' added=', 1)[0]
        trailing = l.split(' added=', 1)[1]
        modified = trailing.split(' modified=', 1)[1]
        modified = modified.split('Z', 1)[0]
        # TODO: 2038
        d = time.strptime(modified, '%Y-%m-%dT%H:%M:%S')
        epoch = time.mktime(d)
        epoch = int(epoch)
        recent_files.append(fname)

        try:
            times.index(epoch)
            # gedit has given multiple files the same modification time
            epoch += uniquifier
            uniquifier += 1
        except:
            pass                    # Not a duplicate time
        times.append(epoch)

    N=5
    top_files = []
    if N > len(times):
        # Less than 5 most recent files in list
        N = len(times)
        if N == 0:
            # No most recent files in list
            return top_files            # return empty list

    # Store list in tmp to retrieve index
    tmp=list(times)
    # Sort list so that largest elements are on the far right
    times.sort()

    #print ('5 most recent from lists and indices')
    for i in range(1, N+1):
        top_files.append(recent_files[tmp.index(times[-i])])

    return top_files


if __name__ == "__main__":

    gedit()