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, 34 insertions, 0 deletions

diff --git a/src/libgit2/libgit2.c b/src/libgit2/libgit2.c
index 5d796b1f7..7244c48d9 100644
--- a/src/libgit2/libgit2.c
+++ b/src/libgit2/libgit2.c
@@ -47,6 +47,8 @@ extern size_t git_indexer__max_objects;
 extern bool git_disable_pack_keep_file_checks;
 extern int git_odb__packed_priority;
 extern int git_odb__loose_priority;
+extern int git_socket_stream__connect_timeout;
+extern int git_socket_stream__timeout;
 
 char *git__user_agent;
 char *git__ssl_ciphers;
@@ -435,6 +437,38 @@ int git_libgit2_opts(int key, ...)
 		error = git_sysdir_set(GIT_SYSDIR_HOME, va_arg(ap, const char *));
 		break;
 
+	case GIT_OPT_GET_SERVER_CONNECT_TIMEOUT:
+		*(va_arg(ap, int *)) = git_socket_stream__connect_timeout;
+
+	case GIT_OPT_SET_SERVER_CONNECT_TIMEOUT:
+		{
+			int timeout = va_arg(ap, int);
+
+			if (timeout < 0) {
+				git_error_set(GIT_ERROR_INVALID, "invalid connect timeout");
+				error = -1;
+			} else {
+				git_socket_stream__connect_timeout = timeout;
+			}
+		}
+		break;
+
+	case GIT_OPT_GET_SERVER_TIMEOUT:
+		*(va_arg(ap, int *)) = git_socket_stream__timeout;
+
+	case GIT_OPT_SET_SERVER_TIMEOUT:
+		{
+			int timeout = va_arg(ap, int);
+
+			if (timeout < 0) {
+				git_error_set(GIT_ERROR_INVALID, "invalid timeout");
+				error = -1;
+			} else {
+				git_socket_stream__timeout = timeout;
+			}
+		}
+		break;
+
 	default:
 		git_error_set(GIT_ERROR_INVALID, "invalid option key");
 		error = -1;