Added Downloader cog (#786)

cogs/downloader/errors.py

@@ -0,0 +1,79 @@
+class DownloaderException(Exception):
+    """
+    Base class for Downloader exceptions.
+    """
+    pass
+
+
+class GitException(DownloaderException):
+    """
+    Generic class for git exceptions.
+    """
+
+
+class InvalidRepoName(DownloaderException):
+    """
+    Throw when a repo name is invalid. Check
+        the message for a more detailed reason.
+    """
+    pass
+
+
+class ExistingGitRepo(DownloaderException):
+    """
+    Thrown when trying to clone into a folder where a
+        git repo already exists.
+    """
+    pass
+
+
+class MissingGitRepo(DownloaderException):
+    """
+    Thrown when a git repo is expected to exist but
+        does not.
+    """
+    pass
+
+
+class CloningError(GitException):
+    """
+    Thrown when git clone returns a non zero exit code.
+    """
+    pass
+
+
+class CurrentHashError(GitException):
+    """
+    Thrown when git returns a non zero exit code attempting
+        to determine the current commit hash.
+    """
+    pass
+
+
+class HardResetError(GitException):
+    """
+    Thrown when there is an issue trying to execute a hard reset
+        (usually prior to a repo update).
+    """
+    pass
+
+
+class UpdateError(GitException):
+    """
+    Thrown when git pull returns a non zero error code.
+    """
+    pass
+
+
+class GitDiffError(GitException):
+    """
+    Thrown when a git diff fails.
+    """
+    pass
+
+
+class PipError(DownloaderException):
+    """
+    Thrown when pip returns a non-zero return code.
+    """
+    pass