wait for refreshing modules to finish before repainting panel

If a max paint delay is set, the panel waits up to this amount of time
for any refreshing modules to finish before triggering a repaint. A
repaint is triggered once either all refreshing modules finish or this
delay elapses. Any individual module may request an immediate repaint.

1 files changed, 40 insertions, 13 deletions

diff --git a/panel.py b/panel.py
index 34dc3d6..b522dc5 100755
--- a/panel.py
+++ b/panel.py
@@ -54,6 +54,8 @@ class Fmt:
 class Mod:
     def __init__(self, spacing=1, spacing_l=None, spacing_r=None):
         self.e_repaint = None
+        self.e_flush = None
+        self.refreshing = False
 
         self.spacing_l = spacing_l if spacing_l is not None else spacing
         self.spacing_r = spacing_r if spacing_r is not None else spacing
@@ -62,7 +64,9 @@ class Mod:
         # this at any time.
         self.out = None
 
-    def repaint(self):
+    def repaint(self, flush=False):
+        if flush:
+            self.e_flush.set()
         self.e_repaint.set()
 
     def run(self):
@@ -104,6 +108,7 @@ class ModDate(Mod):
 
     def work(self):
         while True:
+            self.refreshing = True
             fmt = self.fmts[self.fmt]
             tz = self.tzs[self.tz]
             tz_id = tz['id']
@@ -120,7 +125,8 @@ class ModDate(Mod):
                         + Fmt.spacer()
                         + Fmt.clickable(
                             '', f'{id(self)} fmt', dt.strftime(fmt))))
-            self.repaint()
+            self.refreshing = False
+            self.repaint(flush=True)
 
             self.e.wait(1 - (dt.microsecond / 1000000))
             self.e.clear()
@@ -221,6 +227,7 @@ class ModHLWMTags(ModHLWMBase):
         return Fmt.clickable('', f'{id(self)} use {tag}', buf)
 
     def refresh(self):
+        self.refreshing = True
         tags = self.hc('tag_status').lstrip('\t').split('\t')
         focused = self.hc('attr', 'tags.focus.name')
 
@@ -230,6 +237,7 @@ class ModHLWMTags(ModHLWMBase):
                 5, f'{id(self)} use_index -1',
                 ''.join(
                     self.fmt_tag(tag[0], tag[1:], focused) for tag in tags)))
+        self.refreshing = False
         self.repaint()
 
     def process_cmd(self, cmd):
@@ -246,11 +254,13 @@ class ModHLWMTitle(ModHLWMBase):
         self.refresh()
 
     def refresh(self):
+        self.refreshing = True
         title = self.hc('attr', 'clients.focus.title')
         self.out = (
             title[0:self.max_len-1] + '…'
                 if self.max_len and len(title) > self.max_len
                 else title)
+        self.refreshing = False
         self.repaint()
 
 class ModInputAvail(Mod):
@@ -297,12 +307,14 @@ class ModInputAvail(Mod):
                     self._update_state(False)
 
     def _update_state(self, avail):
+        self.refreshing = True
         if avail and self.avail_text is not None:
             self.out = Fmt.bg(self.avail_bg, Fmt.pad(self.avail_text))
         elif not avail and self.unavail_text is not None:
             self.out = Fmt.bg(self.unavail_bg, Fmt.pad(self.unavail_text))
         else:
             self.out = None
+        self.refreshing = False
         self.repaint()
 
 class IntervalTimer():
@@ -311,7 +323,6 @@ class IntervalTimer():
         self.lock = threading.Lock()
         self.func_intervals = {}
         self.func_next_time = {}
-        self.e_repaint = None
 
     def run(self):
         with self.lock:
@@ -326,7 +337,6 @@ class IntervalTimer():
                 if now > self.func_next_time.get(func, 0):
                     func()
                     self.func_next_time[func] = now - (now % ival) + ival
-            self.e_repaint.set()
             time.sleep(min(self.func_next_time.values()) - time.time())
 
 class ModInterval(Mod):
@@ -334,13 +344,17 @@ class ModInterval(Mod):
 
     def __init__(self, interval=1, **kwargs):
         super().__init__(**kwargs)
-        self.timer.func_intervals[self.refresh] = interval
+        self.timer.func_intervals[self.work] = interval
 
     def run(self):
-        if not self.timer.e_repaint:
-            self.timer.e_repaint = self.e_repaint
         self.timer.run()
 
+    def work(self):
+        self.refreshing = True
+        self.refresh()
+        self.refreshing = False
+        self.repaint()
+
 class ModNetIf(ModInterval):
     def __init__(self, ifname, label=None, regex=False, **kwargs):
         super().__init__(**kwargs)
@@ -368,12 +382,15 @@ class ModMem(ModInterval):
         self.out = Fmt.labelled('MEM', f'{percent:.0f}%%')
 
 class Panel:
-    def __init__(self, *mods):
+    def __init__(self, *mods, max_paint_delay=0):
         self.e_repaint = threading.Event()
+        self.e_flush = threading.Event()
         self.mods = mods
         for m in self.mods:
             m.e_repaint = self.e_repaint
+            m.e_flush = self.e_flush
         self.mod_by_id = {id(m): m for m in self.mods}
+        self.max_paint_delay = max_paint_delay
 
     def process_cmds(self, pipe):
         while True:
@@ -404,10 +421,19 @@ class Panel:
         ).start()
 
         while True:
-                self.e_repaint.wait()
-                self.e_repaint.clear()
-                print(''.join([s for m in self.mods if (s := m.to_paint())]),
-                    file=self.panel.stdin, flush=True)
+            self.e_repaint.wait()
+            self.e_repaint.clear()
+            if not self.e_flush.is_set() and self.max_paint_delay:
+                max_t = time.monotonic() + self.max_paint_delay
+                while (any(x.refreshing for x in self.mods)
+                        and (timeout := max_t - time.monotonic()) > 0):
+                    self.e_repaint.wait(timeout)
+                    self.e_repaint.clear()
+                    if self.e_flush.is_set():
+                        break
+            self.e_flush.clear()
+            print(''.join([s for m in self.mods if (s := m.to_paint())]),
+                file=self.panel.stdin, flush=True)
 
 Panel(
     ModHLWMTags(spacing=0),
@@ -422,5 +448,6 @@ Panel(
     ModDate(
         fmts=('%Y-%m-%d %H:%M:%S', '%H:%M'),
         tzs=({'id': None}, {'id': 'UTC'},
-            {'id': 'Asia/Yerevan', 'label': 'AMT'}))
+            {'id': 'Asia/Yerevan', 'label': 'AMT'})),
+    max_paint_delay=0.01
 ).run()