From 72f355bb64e05f6e9cc848445c026bfbbafca3ae Mon Sep 17 00:00:00 2001
From: Rapptz <rapptz@gmail.com>
Date: Tue, 8 Dec 2015 19:37:34 -0500
Subject: [PATCH] Add OpusNotLoaded exception and opus.is_loaded utility
 function.

---
 discord/client.py |  2 ++
 discord/opus.py   | 31 +++++++++++++++++++++++++++++--
 docs/api.rst      |  6 +++++-
 3 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/discord/client.py b/discord/client.py
index 172634710..ff5ec16fa 100644
--- a/discord/client.py
+++ b/discord/client.py
@@ -1879,6 +1879,8 @@ class Client:
             Could not connect to the voice channel in time.
         ClientException
             You are already connected to a voice channel.
+        OpusNotLoaded
+            The opus library has not been loaded.
 
         Returns
         -------
diff --git a/discord/opus.py b/discord/opus.py
index 68c6a3ec4..2f1e2d1d3 100644
--- a/discord/opus.py
+++ b/discord/opus.py
@@ -111,13 +111,37 @@ def load_opus(name):
     global _lib
     _lib = libopus_loader(name)
 
+def is_loaded():
+    """Function to check if opus lib is successfully loaded either
+    via the ``ctypes.util.find_library`` call of :func:`load_opus`.
+
+    This must return ``True`` for voice to work.
+
+    Returns
+    -------
+    bool
+        Indicates if the opus library has been loaded.
+    """
+    global _lib
+    return _lib is not None
+
 class OpusError(DiscordException):
-    """An exception that is thrown for libopus related errors."""
+    """An exception that is thrown for libopus related errors.
+
+    Attributes
+    ----------
+    code : int
+        The error code returned.
+    """
     def __init__(self, code):
         self.code = code
         msg = _lib.opus_strerror(self.code).decode('utf-8')
         log.info('"{}" has happened'.format(msg))
-        super(DiscordException, self).__init__(msg)
+        super().__init__(msg)
+
+class OpusNotLoaded(DiscordException):
+    """An exception that is thrown for when libopus is not loaded."""
+    pass
 
 
 # Some constants...
@@ -137,6 +161,9 @@ class Encoder:
         self.samples_per_frame = int(self.sampling_rate / 1000 * self.frame_length)
         self.frame_size = self.samples_per_frame * self.sample_size
 
+        if not is_loaded():
+            raise OpusNotLoaded()
+
         self._state = self._create_state()
 
     def __del__(self):
diff --git a/docs/api.rst b/docs/api.rst
index e503e703c..05d84c318 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -33,6 +33,8 @@ Opus Library
 
 .. autofunction:: opus.load_opus
 
+.. autofunction:: opus.is_loaded
+
 .. _discord-api-events:
 
 Event Reference
@@ -457,4 +459,6 @@ The following exceptions are thrown by the library.
 
 .. autoexception:: GatewayNotFound
 
-.. autoexception:: OpusError
+.. autoexception:: opus.OpusError
+
+.. autoexception:: opus.OpusNotLoaded