Introduce stackable IO streams

We currently have gitno for talking over TCP, but this needs to know
about both plaintext and OpenSSL connections and the code has gotten
somewhat messy with ifdefs determining which version of the function
should be called.

In order to clean this up and abstract away the details of sending over
the different types of streams, we can instead use an interface and
stack stream implementations.

We may not be able to use the stackability with all streams, but we
are definitely be able to use the abstraction which is currently spread
between different bits of gitno.

1 files changed, 40 insertions, 0 deletions

diff --git a/include/git2/sys/stream.h b/include/git2/sys/stream.h
new file mode 100644
index 000000000..69f8554da
--- /dev/null
+++ b/include/git2/sys/stream.h
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_sys_git_stream_h__
+#define INCLUDE_sys_git_stream_h__
+
+#include "git2/common.h"
+#include "git2/types.h"
+
+GIT_BEGIN_DECL
+
+#define GIT_STREAM_VERSION 1
+
+/**
+ * Every stream must have this struct as its first element, so the
+ * API can talk to it. You'd define your stream as
+ *
+ *     struct my_stream {
+ *             git_stream parent;
+ *             ...
+ *     }
+ *
+ * and fill the functions
+ */
+typedef struct git_stream {
+	int version;
+
+	int encrypted;
+	int (*connect)(struct git_stream *);
+	int (*certificate)(git_cert **, struct git_stream *);
+	ssize_t (*read)(struct git_stream *, void *, size_t);
+	ssize_t (*write)(struct git_stream *, void *, size_t, int);
+	int (*close)(struct git_stream *);
+	void (*free)(struct git_stream *);
+} git_stream;
+
+#endif