stop animation based on event; add new animation symbols (#196)

Author: Chad Smith

pipx/animate.py

@@ -1,44 +1,59 @@
 from contextlib import contextmanager
 import sys
-from typing import Dict
-from threading import Thread
-from time import sleep
+from typing import List
+from threading import Thread, Event
+from pipx.util import emoji_support
 
 
 @contextmanager
 def animate(message: str, do_animation: bool):
-    animate = {"do_animation": do_animation, "message": message}
-    t = Thread(target=print_animation, args=(animate,))
-    t.start()
+    event = Event()
+
+    if emoji_support:
+        symbols = ["⣷", "⣯", "⣟", "⡿", "⢿", "⣻", "⣽", "⣾"]
+        message = message + " "
+        incremental_wait_time = 0.1
+    else:
+        symbols = ["", ".", "..", "..."]
+        incremental_wait_time = 1
+    max_symbol_len = max(len(s) for s in symbols)
+    spaces = " " * (len(message) + max_symbol_len)
+    clear_line = f"\r{spaces}\r"
+
+    thread_kwargs = {
+        "message": message,
+        "clear_line": clear_line,
+        "event": event,
+        "symbols": symbols,
+        "delay": 0,
+        "incremental_wait_time": incremental_wait_time,
+    }
+
+    if do_animation and sys.stderr.isatty():
+        t = Thread(target=print_animation, kwargs=thread_kwargs)
+        t.start()
+
     try:
         yield
     finally:
-        animate["do_animation"] = False
-        t.join(0)
+        event.set()
+        sys.stderr.write(clear_line)
 
 
-def print_animation(meta: Dict[str, bool]):
-    if not sys.stdout.isatty():
+def print_animation(
+    *,
+    message: str,
+    clear_line: str,
+    event: Event,
+    symbols: List[str],
+    delay: float,
+    incremental_wait_time: float,
+):
+    if event.wait(delay):
         return
-
-    cur = "."
-    longest_len = 0
-    sleep(1)
-    while meta["do_animation"]:
-        if cur == "":
-            cur = "."
-        elif cur == ".":
-            cur = ".."
-        elif cur == "..":
-            cur = "..."
-        else:
-            cur = ""
-        message = f"{meta['message']}{cur}"
-        longest_len = max(len(message), longest_len)
-        sys.stdout.write(" " * longest_len)
-        sys.stdout.write("\r")
-        sys.stdout.write(message)
-        sys.stdout.write("\r")
-        sleep(0.5)
-    sys.stdout.write(" " * longest_len)
-    sys.stdout.write("\r")
+    while True:
+        for s in symbols:
+            cur_line = f"{message}{s}"
+            sys.stderr.write(clear_line + cur_line + "\r")
+            if event.wait(incremental_wait_time):
+                return

pipx/emojies.py

@@ -1,10 +1,10 @@
-from pipx.util import WINDOWS
+from pipx.util import emoji_support
 
-if WINDOWS:
-    stars = ""
-    hazard = ""
-    sleep = ""
-else:
+if emoji_support:
     stars = "✨ 🌟 ✨"
     hazard = "⚠️"
     sleep = "😴"
+else:
+    stars = ""
+    hazard = ""
+    sleep = ""

pipx/util.py

@@ -18,6 +18,8 @@ class PipxError(Exception):
 else:
     WINDOWS = True
 
+emoji_support = not WINDOWS and sys.getdefaultencoding() == "utf-8"
+
 
 def rmdir(path: Path):
     logging.info(f"removing directory {path}")