receiver: gather host names from HOSTS_INFO feature and show them

docs/features.md

@@ -34,7 +34,7 @@ Feature                                | ID       | Status             | Notes
 `OOBSTATE`                             | `0x1805` | :x:                |
 `CONFIG_DEVICE_PROPS`                  | `0x1806` | :x:                |
 `CHANGE_HOST`                          | `0x1814` | :x:                |
-`HOSTS_INFO`                           | `0x1815` | :x:                |
+`HOSTS_INFO`                           | `0x1815` | :heavy_plus_sign:  | `get_host_names`, partial listing only
 `BACKLIGHT`                            | `0x1981` | :x:                |
 `BACKLIGHT2`                           | `0x1982` | :heavy_check_mark: | `_feature_backlight2`
 `BACKLIGHT3`                           | `0x1983` | :x:                |

lib/logitech_receiver/hidpp20.py

@@ -651,9 +651,36 @@ def get_hires_wheel(device):
 
 def get_new_fn_inversion(device):
     state = feature_request(device, FEATURE.NEW_FN_INVERSION, 0x00)
-
     if state:
         inverted, default_inverted = _unpack('!BB', state[:2])
         inverted = (inverted & 0x01) != 0
         default_inverted = (default_inverted & 0x01) != 0
         return inverted, default_inverted
+
+
+def get_host_names(device):
+    state = feature_request(device, FEATURE.HOSTS_INFO, 0x00)
+    host_names = {}
+    if state:
+        _ignore, _ignore, numHosts, currentHost = _unpack('!BBBB', state[:4])
+        for host in range(0, numHosts):
+            hostinfo = feature_request(device, FEATURE.HOSTS_INFO, 0x10, host)
+            _ignore, status, _ignore, numPages, nameLen, _ignore = _unpack('!BBBBBB', hostinfo[:6])
+            name = ''
+            remaining = nameLen
+            while remaining > 0:
+                name_piece = feature_request(device, FEATURE.HOSTS_INFO, 0x30, host, nameLen - remaining)
+                name += name_piece[2:2 + min(remaining, 14)].decode()
+                remaining = max(0, remaining - 14)
+            host_names[host] = (bool(status), name)
+    return host_names
+
+
+def set_host_name(device, name):
+    state = feature_request(device, FEATURE.HOSTS_INFO, 0x00)
+    if state:
+        flags = _unpack('!B', state[:1])[0]
+        if flags & 0x02:
+            hn = name[:min(14, name.find('.'))] if name.find('.') >= 0 else name
+            response = feature_request(device, FEATURE.HOSTS_INFO, 0x40, 0xff, 0, hn)
+            return response

lib/solaar/cli/show.py

@@ -172,6 +172,10 @@ def _print_device(dev):
                 inverted, default_inverted = _hidpp20.get_new_fn_inversion(dev)
                 print('            Fn-swap:', 'enabled' if inverted else 'disabled')
                 print('            Fn-swap default:', 'enabled' if default_inverted else 'disabled')
+            elif feature == _hidpp20.FEATURE.HOSTS_INFO:
+                host_names = _hidpp20.get_host_names(dev)
+                for host, (paired, name) in host_names.items():
+                    print('            Host %s (%s): %s' % (host, 'paired' if paired else 'unpaired', name))
             for setting in dev_settings:
                 if setting.feature == feature:
                     v = setting.read(False)