add support in ui to toggle, kill and revive

Signed-off-by: Mattias Andrée <maandree@operamail.com>

3 files changed, 100 insertions, 15 deletions

diff --git a/DEPENDENCIES b/DEPENDENCIES
index e20c8af..23c729c 100644
--- a/DEPENDENCIES
+++ b/DEPENDENCIES
@@ -2,6 +2,7 @@ RUNTIME DEPENDENCIES:
 
 	redshift
 	python3
+	linux (procfs is used to reexec python)
 
 MAKE DEPENDENCIES:
 
diff --git a/src/interface.py b/src/interface.py
index 3bb096c..295d3b6 100644
--- a/src/interface.py
+++ b/src/interface.py
@@ -26,6 +26,10 @@ import termios
 import threading
 
 
+ui_state = { 'focus' : 0
+           }
+
+
 def user_interface():
     '''
     Start user interface
@@ -33,7 +37,7 @@ def user_interface():
     global red_condition
     red_condition = threading.Condition()
     ui_winch()
-    daemon_thread(ui_status, args = (ui_status_callback,)).start()
+    daemon_thread(ui_status).start()
     daemon_thread(ui_refresh).start()
     
     print('\033[?1049h\033[?25l')
@@ -59,8 +63,13 @@ def ui_print():
         print('Brightness: %.0f %% (day: %.0f %%, night: %.0f %%)' % tuple(brightness))
         print('Dayness: %.0f %%' % (red_period * 100))
         print('Enabled' if red_status else 'Disabled')
+        print()
+        print(('[%s]' if ui_state['focus'] == 0 else '<%s>') % ('Disable' if red_status else 'Enable'), end='  ')
+        print(('[%s]' if ui_state['focus'] == 1 else '<%s>') % 'Kill')
     else:
         print('Not running')
+        print()
+        print('[%s]' % 'Revive')
 
 
 def ui_read():
@@ -69,6 +78,29 @@ def ui_read():
         c = inbuf.read(1)
         if c == b'q':
             break
+        elif c == b'\t':
+            red_condition.acquire()
+            try:
+                ui_state['focus'] = 1 - ui_state['focus']
+                red_condition.notify()
+            finally:
+                red_condition.release()
+        elif c in b' \n':
+            red_condition.acquire()
+            try:
+                if red_running:
+                    if ui_state['focus'] == 0:
+                        sock.sendall('toggle\n'.encode('utf-8'))
+                    else:
+                        sock.sendall('kill\n'.encode('utf-8'))
+                    red_condition.notify()
+                else:
+                    respawn_daemon()
+                    daemon_thread(ui_status).start()
+                    sock.sendall('status\n'.encode('utf-8'))
+                    sock.sendall('listen\n'.encode('utf-8'))
+            finally:
+                red_condition.release()
 
 
 def ui_refresh():
@@ -95,7 +127,7 @@ def ui_winch():
     signal.signal(signal.SIGWINCH, winch)
 
 
-def ui_status(callback):
+def ui_status():
     buf = ''
     continue_to_run = True
     while continue_to_run:
@@ -109,8 +141,8 @@ def ui_status(callback):
                 break
         if continue_to_run:
             msg, buf = buf.split('\n\n')[0], '\n\n'.join(buf.split('\n\n')[1:])
-            callback(dict([line.split(': ') for line in msg.split('\n')]))
-    callback(None)
+            ui_status_callback(dict([line.split(': ') for line in msg.split('\n')]))
+    ui_status_callback(None)
 
 
 def ui_status_callback(status):
diff --git a/src/nightshift.py b/src/nightshift.py
index fdaafd6..428cb9a 100755
--- a/src/nightshift.py
+++ b/src/nightshift.py
@@ -83,9 +83,9 @@ red_opts = ['-v']
 :list<str>  Nightshift parsed options passed to redshift
 '''
 
-daemon = False
+daemon = 0
 '''
-:bool  Whether or not to run as daemon
+:int  Whether or not to run as daemon, 2 if revived
 '''
 
 kill = 0
@@ -197,7 +197,8 @@ for arg in sys.argv[1:]:
                 red_arg += arg[1]
             elif isinstance(config_file, list):
                 config_file.append(arg[1])
-            elif arg in ('-d', '--daemon'):             daemon = True
+            elif arg in ('-d', '--daemon'):             daemon = 1
+            elif arg in ('+d', '++daemon'):             daemon = 2
             elif arg in ('-x', '--reset', '--kill'):    kill += 1
             elif arg in ('+x', '--toggle'):             toggle = True
             elif arg in ('-s', '--status'):             status = True
@@ -440,13 +441,16 @@ def run_as_daemon(sock):
     thread.join()
 
 
-def do_daemon():
+def do_daemon(reexec):
     '''
-    Run actions for --daemon
+    Run actions for --daemon or ++daemon
+    
+    @param  reexec:bool  Wether to perform actions for ++daemon
     '''
-    if (kill > 0) or toggle or status:
-        print('%s: error: -x, +x and -s can be used when running as the daemon' % sys.argv[0])
-        sys.exit(1)
+    if not reexec:
+        if (kill > 0) or toggle or status:
+            print('%s: error: -x, +x and -s can be used when running as the daemon' % sys.argv[0])
+            sys.exit(1)
     
     # Create server socket
     try:
@@ -457,6 +461,11 @@ def do_daemon():
     sock.bind(socket_path)
     sock.listen(backlog)
     
+    # Signal respawner
+    if reexec:
+        print()
+        sys.stdout.close()
+    
     # Perform daemon logic
     run_as_daemon(sock)
     
@@ -631,12 +640,55 @@ def do_client():
     sock.close()
 
 
+def respawn_daemon():
+    '''
+    Restart the nightshift daemon
+    '''
+    global sock
+    
+    # Close old socket
+    sock.close()
+    
+    ## Server is not running
+    # Create pipe for interprocess signal
+    (r_end, w_end) = os.pipe()
+    
+    # Duplicate process
+    pid = os.fork()
+    
+    if pid == 0:
+        ## Daemon (child)
+        # Close stdin and stdout
+        os.close(sys.stdin.fileno())
+        os.close(sys.stdout.fileno())
+        
+        # Replace stdout with the pipe
+        os.dup2(w_end, sys.stdout.fileno())
+        os.close(w_end)
+        
+        # Reexecute image
+        os.execl('/proc/self/exe', '/proc/self/exe', *(sys.argv + ['+d']))
+    else:
+        ## Front-end (parent)
+        # Wait for a signal
+        rc = None
+        with os.fdopen(r_end, 'rb') as file:
+            file.read(1)
+        
+        # Close the pipe
+        os.close(w_end)
+        
+        # Connect to the server
+        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        sock.connect(socket_path)
+
+
 def run():
     '''
-    Run as either the daemon (if --daemon) or as a client (otherwise)
+    Run as either the daemon (if --daemon or ++daemon) or as a client (otherwise)
     '''
-    if daemon:
-        do_daemon()
+    if daemon > 0:
+        do_daemon(daemon == 2)
     else:
         do_client()