Speed up IF reads with chunked I/O and short idle timeout

src/mudlib/if_session.py

@@ -170,34 +170,38 @@ class IFSession:
         if not self.process or not self.process.stdout:
             return ""
 
-        output = []
+        buf = b""
+        idle_timeout = 0.1  # return quickly once data stops flowing
+        overall_deadline = asyncio.get_event_loop().time() + 5.0
+
         try:
-            # Read byte by byte until we see "\n>"
             while True:
-                byte = await asyncio.wait_for(self.process.stdout.read(1), timeout=5.0)
+                remaining = overall_deadline - asyncio.get_event_loop().time()
-                if not byte:
+                if remaining <= 0:
-                    break
-
-                char = byte.decode("latin-1")
-                output.append(char)
-
-                # Check if we've hit the prompt
-                # Prompt is "\n>" or just ">" at start
-                if len(output) >= 2:
-                    if output[-2] == "\n" and output[-1] == ">":
-                        # Strip the trailing "\n>"
-                        output = output[:-2]
-                        break
-                elif len(output) == 1 and output[0] == ">":
-                    # Prompt at very start
-                    output = []
                     break
+                timeout = min(idle_timeout, remaining)
+                try:
+                    chunk = await asyncio.wait_for(
+                        self.process.stdout.read(1024), timeout=timeout
+                    )
+                except TimeoutError:
+                    # No data for idle_timeout - dfrotz is done talking
+                    break
+                if not chunk:
+                    break
+                buf += chunk
+
+                # Check for prompt at end of buffer
+                text = buf.decode("latin-1")
+                if text.endswith("\n>"):
+                    text = text[:-2]
+                    return text.rstrip()
+                if text == ">":
+                    return ""
         except TimeoutError:
-            # If we timeout, return what we got
             pass
 
-        result = "".join(output)
+        return buf.decode("latin-1").rstrip()
-        return result.rstrip()
 
 
 async def broadcast_to_spectators(player: "Player", message: str) -> None: