Merge pull request #536 from alex/prioritized-multi-backend

Initial work on a prioritized multibackend for which implements CipherBackend

2 files changed, 29 insertions, 0 deletions

diff --git a/docs/hazmat/backends/index.rst b/docs/hazmat/backends/index.rst
index dbc0724e..983a44e9 100644
--- a/docs/hazmat/backends/index.rst
+++ b/docs/hazmat/backends/index.rst
@@ -32,4 +32,5 @@ Individual Backends
 
     openssl
     commoncrypto
+    multibackend
     interfaces
diff --git a/docs/hazmat/backends/multibackend.rst b/docs/hazmat/backends/multibackend.rst
new file mode 100644
index 00000000..63177bef
--- /dev/null
+++ b/docs/hazmat/backends/multibackend.rst
@@ -0,0 +1,28 @@
+.. hazmat::
+
+MultiBackend
+============
+
+.. currentmodule:: cryptography.hazmat.backends.multibackend
+
+.. class:: MultiBackend(backends)
+
+    .. versionadded:: 0.2
+
+    This class allows you to combine multiple backends into a single backend
+    which offers the combined features of all of its constituents.
+
+    .. code-block:: pycon
+
+        >>> from cryptography.hazmat.backends.multibackend import MultiBackend
+        >>> from cryptography.hazmat.primitives import hashes
+        >>> backend1.hash_supported(hashes.SHA256())
+        False
+        >>> backend2.hash_supported(hashes.SHA1())
+        True
+        >>> multi_backend = MultiBackend([backend1, backend2])
+        >>> multi_backend.hash_supported(hashes.SHA1())
+        True
+
+    :param backends: A ``list`` of backend objects. Backends are checked for
+                     feature support in the order they appear in this list.