Introduces Gio to tell the user that their password is being verified
instead of just freezing the GUI.
---
 hiprompt_gtk/proto.py  | 66 ++++++++++++++++++++++++++++++++----------
 hiprompt_gtk/window.py | 49 ++++++++++++++++++++-----------
 2 files changed, 83 insertions(+), 32 deletions(-)

diff --git a/hiprompt_gtk/proto.py b/hiprompt_gtk/proto.py
index 5f4749f..fecaf6a 100644
--- a/hiprompt_gtk/proto.py
+++ b/hiprompt_gtk/proto.py
@@ -1,8 +1,39 @@
 import sys
 from enum import Enum
+from gi.repository import GLib, Gio
 from .key import Key
 
 
+def gio_lines(stream):
+    line = bytearray()
+
+    while not stream.is_closed():
+        byte = stream.read_bytes(1).get_data()
+        if not byte:
+            return
+        line += byte
+        if line[-1] == ord("\n"):
+            yield line.decode()
+            line.clear()
+
+def gio_lines_async(stream, callback):
+    line = bytearray()
+
+    def _callback(source, result):
+        nonlocal line
+        byte = source.read_bytes_finish(result).get_data() if result else b""
+        line += byte
+        if line and line[-1] == ord("\n"):
+            more = callback(line.decode())
+            if not more:
+                return
+            line.clear()
+
+        stream.read_bytes_async(1, GLib.PRIORITY_DEFAULT, None, _callback)
+
+    _callback(stream, None)
+
+
 class PromptMode(Enum):
     disclose = "disclose"
     delete = "delete"
@@ -14,10 +45,11 @@ class Session:
         self.unlock = False
         self.status = 127
         self.mode = None
+        self.stream = Gio.UnixInputStream.new(sys.stdin.fileno(), False)
         self.parse()
 
     def parse(self):
-        for line in sys.stdin:
+        for line in gio_lines(self.stream):
             parts = line.strip().partition(" ")
             cmd = parts[0]
             args = parts[2]
@@ -44,22 +76,26 @@ class Session:
         self.mode = PromptMode(args)
         return False
 
-    def password(self, pw):
+    def password(self, pw, callback):
         """
-        Sends a password to the daemon in response to an unlock command. Blocks
-        until the daemon answers regarding the password's validity, returning
-        True if it was correct and False otherwise.
+        Sends a password to the daemon in response to an unlock command and
+        returns immediately. When the daemon answers regarding the password's
+        validity, calls the callback function with one argument: True if it was
+        correct and False otherwise.
         """
         sys.stdout.write(f"password {pw}\n")
         sys.stdout.flush()
-        # TODO: Don't block
-        line = sys.stdin.readline()
-        if line == "password incorrect\n":
+
+        def _callback(line):
+            if line == "password incorrect\n":
+                callback(False)
+            elif line == "password correct\n":
+                self.unlock = False
+                self.parse()
+                callback(True)
+            else:
+                sys.stderr.write(f"Unexpected command '{line}'\n")
+                exit(127)
             return False
-        elif line == "password correct\n":
-            self.unlock = False
-            self.parse()
-            return True
-        else:
-            sys.stderr.write(f"Unexpected command '{line}'\n")
-            exit(127)
+
+        gio_lines_async(self.stream, _callback)
diff --git a/hiprompt_gtk/window.py b/hiprompt_gtk/window.py
index 1f80ae4..4afed53 100644
--- a/hiprompt_gtk/window.py
+++ b/hiprompt_gtk/window.py
@@ -23,6 +23,8 @@ class Window:
         self.box = Gtk.Box(orientation=Gtk.Orientation.VERTICAL)
         self.window.add(self.box)
 
+        self.deny = None
+        self.grant = None
         self.entry = None
         self.buttons = []
 
@@ -63,17 +65,30 @@ class Window:
 
     def on_unlock_grant(self, *args):
         password = self.entry.get_text()
+        self.deny.set_sensitive(False)
+        self.grant.set_sensitive(False)
         self.entry.set_sensitive(False)
+        self.entry.set_text("Verifying...")
+        self.entry.set_visibility(True)
+        self.window.remove_accel_group(self.accel)
         confirmed = len(self.session.keys) > 0
-        if self.session.password(password):
-            if not self.session.mode or confirmed:
-                self.session.status = 0
-                Gtk.main_quit()
+
+        def _callback(status):
+            if status:
+                if not self.session.mode or confirmed:
+                    self.session.status = 0
+                    Gtk.main_quit()
+                else:
+                    self.make_ui()
             else:
-                self.make_ui()
-        else:
-            self.entry.set_text("")
-            self.entry.set_sensitive(True)
+                self.entry.set_text("")
+                self.entry.set_visibility(False)
+                self.entry.set_sensitive(True)
+                self.grant.set_sensitive(True)
+                self.window.add_accel_group(self.accel)
+                self.entry.grab_focus()
+
+        self.session.password(password, _callback)
 
     def on_disclose_grant(self, *args):
         self.session.status = 0
@@ -88,16 +103,16 @@ class Window:
         self.header.set_title("Unlock keyring")
 
         if len(self.session.keys) == 0:
-            deny = Gtk.Button("Cancel")
+            self.deny = Gtk.Button("Cancel")
         else:
-            deny = Gtk.Button("Deny access")
-        deny.connect("clicked", self.on_deny)
-        self.header.pack_start(deny)
-
-        grant = Gtk.Button("Grant access")
-        grant.get_style_context().add_class("destructive-action")
-        grant.connect("clicked", self.on_unlock_grant)
-        self.header.pack_end(grant)
+            self.deny = Gtk.Button("Deny access")
+        self.deny.connect("clicked", self.on_deny)
+        self.header.pack_start(self.deny)
+
+        self.grant = Gtk.Button("Grant access")
+        self.grant.get_style_context().add_class("destructive-action")
+        self.grant.connect("clicked", self.on_unlock_grant)
+        self.header.pack_end(self.grant)
 
         scroller = Gtk.ScrolledWindow()
         scroller.set_propagate_natural_height(True)
-- 
2.36.2