streams: sockets are non-blocking and can timeoutethomson/nonblocking

Make socket I/O non-blocking and add optional timeouts.

Users may now set `GIT_OPT_SET_SERVER_CONNECT_TIMEOUT` to set a shorter
connection timeout. (The connect timeout cannot be longer than the
operating system default.) Users may also now configure the socket read
and write timeouts with `GIT_OPT_SET_SERVER_TIMEOUT`.

By default, connects still timeout based on the operating system
defaults (typically 75 seconds) and socket read and writes block.

Add a test against our custom testing git server that ensures that we
can timeout reads against a slow server.

1 files changed, 16 insertions, 2 deletions

diff --git a/include/git2/sys/stream.h b/include/git2/sys/stream.h
index e0e03a2d7..3d28d09b3 100644
--- a/include/git2/sys/stream.h
+++ b/include/git2/sys/stream.h
@@ -29,8 +29,22 @@ GIT_BEGIN_DECL
 typedef struct git_stream {
 	int version;
 
-	int encrypted;
-	int proxy_support;
+	int encrypted : 1,
+	    proxy_support : 1;
+
+	/**
+	 * Timeout for read and write operations; can be set to `0` to
+	 * block indefinitely.
+	 */
+	int timeout;
+
+	/**
+	 * Timeout to connect to the remote server; can be set to `0`
+	 * to use the system defaults. This can be shorter than the
+	 * system default - often 75 seconds - but cannot be longer.
+	 */
+	int connect_timeout;
+
 	int GIT_CALLBACK(connect)(struct git_stream *);
 	int GIT_CALLBACK(certificate)(git_cert **, struct git_stream *);
 	int GIT_CALLBACK(set_proxy)(struct git_stream *, const git_proxy_options *proxy_opts);