compat/fsmonitor/fsm-listen-win32: stub in backend for Windows

Stub in empty filesystem listener backend for fsmonitor--daemon on Windows.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

compat/fsmonitor/fsm-listen-win32.c

@@ -0,0 +1,21 @@
+#include "cache.h"
+#include "config.h"
+#include "fsmonitor.h"
+#include "fsm-listen.h"
+
+void fsm_listen__stop_async(struct fsmonitor_daemon_state *state)
+{
+}
+
+void fsm_listen__loop(struct fsmonitor_daemon_state *state)
+{
+}
+
+int fsm_listen__ctor(struct fsmonitor_daemon_state *state)
+{
+	return -1;
+}
+
+void fsm_listen__dtor(struct fsmonitor_daemon_state *state)
+{
+}

compat/fsmonitor/fsm-listen.h

@@ -0,0 +1,49 @@
+#ifndef FSM_LISTEN_H
+#define FSM_LISTEN_H
+
+/* This needs to be implemented by each backend */
+
+#ifdef HAVE_FSMONITOR_DAEMON_BACKEND
+
+struct fsmonitor_daemon_state;
+
+/*
+ * Initialize platform-specific data for the fsmonitor listener thread.
+ * This will be called from the main thread PRIOR to staring the
+ * fsmonitor_fs_listener thread.
+ *
+ * Returns 0 if successful.
+ * Returns -1 otherwise.
+ */
+int fsm_listen__ctor(struct fsmonitor_daemon_state *state);
+
+/*
+ * Cleanup platform-specific data for the fsmonitor listener thread.
+ * This will be called from the main thread AFTER joining the listener.
+ */
+void fsm_listen__dtor(struct fsmonitor_daemon_state *state);
+
+/*
+ * The main body of the platform-specific event loop to watch for
+ * filesystem events.  This will run in the fsmonitor_fs_listen thread.
+ *
+ * It should call `ipc_server_stop_async()` if the listener thread
+ * prematurely terminates (because of a filesystem error or if it
+ * detects that the .git directory has been deleted).  (It should NOT
+ * do so if the listener thread receives a normal shutdown signal from
+ * the IPC layer.)
+ *
+ * It should set `state->error_code` to -1 if the daemon should exit
+ * with an error.
+ */
+void fsm_listen__loop(struct fsmonitor_daemon_state *state);
+
+/*
+ * Gently request that the fsmonitor listener thread shutdown.
+ * It does not wait for it to stop.  The caller should do a JOIN
+ * to wait for it.
+ */
+void fsm_listen__stop_async(struct fsmonitor_daemon_state *state);
+
+#endif /* HAVE_FSMONITOR_DAEMON_BACKEND */
+#endif /* FSM_LISTEN_H */