Speedup gita ll by using a threadpool (#238)

Each line of 'll' output is generated from running git commands, by
using a thread pool the commands for each line can be ran in parallel.

Co-authored-by: John Beckett <[email protected]>

gita/utils.py

@@ -9,6 +9,8 @@
 from pathlib import Path
 from typing import List, Dict, Coroutine, Union, Iterator, Tuple
 from collections import Counter, defaultdict
+from concurrent.futures import ThreadPoolExecutor
+import multiprocessing
 
 from . import info
 from . import common
@@ -428,17 +430,20 @@ def describe(repos: Dict[str, Dict[str, str]], no_colors: bool = False) -> str:
     Return the status of all repos
     """
     if repos:
-        name_width = max(len(n) for n in repos) + 1
-    funcs = info.get_info_funcs()
-
-    get_repo_status = info.get_repo_status
-    if get_repo_status in funcs and no_colors:
-        idx = funcs.index(get_repo_status)
-        funcs[idx] = partial(get_repo_status, no_colors=True)
-
-    for name in sorted(repos):
-        info_items = " ".join(f(repos[name]) for f in funcs)
-        yield f"{name:<{name_width}}{info_items}"
+        name_width = len(max(repos, key=len)) + 1
+        funcs = info.get_info_funcs()
+
+        get_repo_status = info.get_repo_status
+        if get_repo_status in funcs and no_colors:
+            idx = funcs.index(get_repo_status)
+            funcs[idx] = partial(get_repo_status, no_colors=True)
+
+        num_threads = min(multiprocessing.cpu_count(), len(repos))
+        with ThreadPoolExecutor(max_workers=num_threads) as executor:
+            for line in executor.map(
+                    lambda repo: f'{repo:<{name_width}}{" ".join(f(repos[repo]) for f in funcs)}',
+                    sorted(repos)):
+                yield line
 
 
 def get_cmds_from_files() -> Dict[str, Dict[str, str]]: