Mitigated performance issues related to SQLite3 randomly hanging for a second on Android

sbapp/ui/messages.py

@@ -37,9 +37,12 @@ class Messages():
     def __init__(self, app, context_dest):
         self.app = app
         self.context_dest = context_dest
-        self.messages = []
+        self.new_messages = []
         self.added_item_hashes = []
+        self.added_messages = 0
         self.latest_message_timestamp = None
+        self.earliest_message_timestamp = time.time()
+        self.loading_earlier_messages = False
         self.list = None
         self.widgets = []
         self.send_error_dialog = None
@@ -50,20 +53,27 @@ class Messages():
         if self.list != None:
             self.list.clear_widgets()
 
-        self.messages = []
+        self.new_messages = []
         self.added_item_hashes = []
+        self.added_messages = 0
         self.latest_message_timestamp = None
         self.widgets = []
 
         self.update()
 
+    def load_more(self, dt):
+        for new_message in self.app.sideband.list_messages(self.context_dest, before=self.earliest_message_timestamp,limit=2):
+            self.new_messages.append(new_message)
+
+        if len(self.new_messages) > 0:
+            self.loading_earlier_messages = True
+            self.list.remove_widget(self.load_more_button)
+
     def update(self, limit=8):
-        s_ts = time.time()
-        self.messages = self.app.sideband.list_messages(self.context_dest, after=self.latest_message_timestamp,limit=limit)
+        for new_message in self.app.sideband.list_messages(self.context_dest, after=self.latest_message_timestamp,limit=limit):
+            self.new_messages.append(new_message)
 
         self.db_message_count = self.app.sideband.count_messages(self.context_dest)
-        RNS.log("Total messages in db: "+str(self.db_message_count))
-        RNS.log("Added items: "+str(len(self.added_item_hashes)))
 
         if self.load_more_button == None:
             self.load_more_button = MDRectangleFlatIconButton(
@@ -73,29 +83,28 @@ class Messages():
                 theme_text_color="Custom",
                 size_hint=[1.0, None],
             )
+            def lmcb(sender):
+                Clock.schedule_once(self.load_more, 0.15)
+
+            self.load_more_button.bind(on_release=lmcb)
 
         if self.list == None:
             layout = GridLayout(cols=1, spacing=dp(16), padding=dp(16), size_hint_y=None)
             layout.bind(minimum_height=layout.setter('height'))
             self.list = layout
-        
-        if (len(self.added_item_hashes) < self.db_message_count) and not self.load_more_button in self.list.children:
-            # if self.load_more_button in self.list.children:
-            #     RNS.log("Removing for reinsertion")
-            #     self.list.remove_widget(self.load_more_button)
-            self.list.add_widget(self.load_more_button, len(self.list.children))
 
         c_ts = time.time()
-        if len(self.messages) > 0:
+        if len(self.new_messages) > 0:
             self.update_widget()
-        RNS.log("Cards created in "+RNS.prettytime(time.time()-c_ts), RNS.LOG_DEBUG)
+
+        if (len(self.added_item_hashes) < self.db_message_count) and not self.load_more_button in self.list.children:
+            self.list.add_widget(self.load_more_button, len(self.list.children))
 
         if self.app.sideband.config["dark_ui"]:
             intensity_msgs = intensity_msgs_dark
         else:
             intensity_msgs = intensity_msgs_light
 
-        upd_ts = time.time()
         for w in self.widgets:
             m = w.m
             if self.app.sideband.config["dark_ui"]:
@@ -141,8 +150,6 @@ class Messages():
                     w.heading = titlestr+"[b]Sent[/b] "+txstr+"\n[b]State[/b] Failed"
                     m["state"] = msg["state"]
 
-        RNS.log("Updated message widgets in "+RNS.prettytime(time.time()-upd_ts), RNS.LOG_DEBUG)
-        RNS.log("Creating messages view took "+RNS.prettytime(time.time()-s_ts), RNS.LOG_DEBUG)
 
     def update_widget(self):
         if self.app.sideband.config["dark_ui"]:
@@ -152,8 +159,10 @@ class Messages():
             intensity_msgs = intensity_msgs_light
             mt_color = [1.0, 1.0, 1.0, 0.95]
 
-        for m in self.messages:
-            s_ts = time.time()
+        if self.loading_earlier_messages:
+            self.new_messages.reverse()
+
+        for m in self.new_messages:
             if not m["hash"] in self.added_item_hashes:
                 txstr = time.strftime(ts_format, time.localtime(m["sent"]))
                 rxstr = time.strftime(ts_format, time.localtime(m["received"]))
@@ -432,14 +441,23 @@ class Messages():
                 # Bind menu open
                 item.ids.msg_submenu.bind(on_release=callback_factory(item))
 
+                if self.loading_earlier_messages:
+                    insert_pos = len(self.list.children)
+                else:
+                    insert_pos = 0
+
                 self.added_item_hashes.append(m["hash"])
                 self.widgets.append(item)
-                self.list.add_widget(item)
+                self.list.add_widget(item, insert_pos)
 
                 if self.latest_message_timestamp == None or m["received"] > self.latest_message_timestamp:
                     self.latest_message_timestamp = m["received"]
 
-                RNS.log("Created message card in "+RNS.prettytime(time.time()-s_ts), RNS.LOG_DEBUG)
+                if self.earliest_message_timestamp == None or m["received"] < self.earliest_message_timestamp:
+                    self.earliest_message_timestamp = m["received"]
+
+        self.added_messages += len(self.new_messages)
+        self.new_messages = []
 
     def get_widget(self):
         return self.list