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

jeffhostetler · gitster · commit 1e7a8f4e58dc · 2022-03-01T10:57:48.000-08:00
Stub in empty filesystem listener backend for fsmonitor--daemon on Windows.

Signed-off-by: Jeff Hostetler &lt;jeffhost@microsoft.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git a/Makefile b/Makefile
@@ -470,6 +470,11 @@ all::
 # directory, and the JSON compilation database 'compile_commands.json' will be
 # created at the root of the repository.
 #
+# If your platform supports a built-in fsmonitor backend, set
+# FSMONITOR_DAEMON_BACKEND to the "<name>" of the corresponding
+# `compat/fsmonitor/fsm-listen-<name>.c` that implements the
+# `fsm_listen__*()` routines.
+#
 # Define DEVELOPER to enable more compiler warnings. Compiler version
 # and family are auto detected, but could be overridden by defining
 # COMPILER_FEATURES (see config.mak.dev). You can still set
@@ -1968,6 +1973,11 @@ ifdef NEED_ACCESS_ROOT_HANDLER
 	COMPAT_OBJS += compat/access.o
 endif
 
+ifdef FSMONITOR_DAEMON_BACKEND
+	COMPAT_CFLAGS += -DHAVE_FSMONITOR_DAEMON_BACKEND
+	COMPAT_OBJS += compat/fsmonitor/fsm-listen-$(FSMONITOR_DAEMON_BACKEND).o
+endif
+
 ifeq ($(TCLTK_PATH),)
 NO_TCLTK = NoThanks
 endif
@@ -2887,6 +2897,9 @@ GIT-BUILD-OPTIONS: FORCE
 	@echo DC_SHA1=\''$(subst ','\'',$(subst ','\'',$(DC_SHA1)))'\' >>$@+
 	@echo SANITIZE_LEAK=\''$(subst ','\'',$(subst ','\'',$(SANITIZE_LEAK)))'\' >>$@+
 	@echo X=\'$(X)\' >>$@+
+ifdef FSMONITOR_DAEMON_BACKEND
+	@echo FSMONITOR_DAEMON_BACKEND=\''$(subst ','\'',$(subst ','\'',$(FSMONITOR_DAEMON_BACKEND)))'\' >>$@+
+endif
 ifdef TEST_OUTPUT_DIRECTORY
 	@echo TEST_OUTPUT_DIRECTORY=\''$(subst ','\'',$(subst ','\'',$(TEST_OUTPUT_DIRECTORY)))'\' >>$@+
 endif
diff --git a/compat/fsmonitor/fsm-listen-win32.c b/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)
+{
+}
diff --git a/compat/fsmonitor/fsm-listen.h b/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 */
diff --git a/config.mak.uname b/config.mak.uname
@@ -435,6 +435,11 @@ ifeq ($(uname_S),Windows)
 	# so we don't need this:
 	#
 	#   SNPRINTF_RETURNS_BOGUS = YesPlease
+
+	# The builtin FSMonitor requires Named Pipes and Threads on Windows.
+	# These are always available, so we do not have to conditionally
+	# support it.
+	FSMONITOR_DAEMON_BACKEND = win32
 	NO_SVN_TESTS = YesPlease
 	RUNTIME_PREFIX = YesPlease
 	HAVE_WPGMPTR = YesWeDo
@@ -619,6 +624,11 @@ ifeq ($(uname_S),MINGW)
 	NO_STRTOUMAX = YesPlease
 	NO_MKDTEMP = YesPlease
 	NO_SVN_TESTS = YesPlease
+
+	# The builtin FSMonitor requires Named Pipes and Threads on Windows.
+	# These are always available, so we do not have to conditionally
+	# support it.
+	FSMONITOR_DAEMON_BACKEND = win32
 	RUNTIME_PREFIX = YesPlease
 	HAVE_WPGMPTR = YesWeDo
 	NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
diff --git a/contrib/buildsystems/CMakeLists.txt b/contrib/buildsystems/CMakeLists.txt
@@ -285,6 +285,13 @@ else()
 	endif()
 endif()
 
+if(SUPPORTS_SIMPLE_IPC)
+	if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
+		add_compile_definitions(HAVE_FSMONITOR_DAEMON_BACKEND)
+		list(APPEND compat_SOURCES compat/fsmonitor/fsm-listen-win32.c)
+	endif()
+endif()
+
 set(EXE_EXTENSION ${CMAKE_EXECUTABLE_SUFFIX})
 
 #header checks
diff --git a/repo-settings.c b/repo-settings.c
@@ -2,6 +2,7 @@
 #include "config.h"
 #include "repository.h"
 #include "midx.h"
+#include "compat/fsmonitor/fsm-listen.h"
 
 static void repo_cfg_bool(struct repository *r, const char *key, int *dest,
 			  int def)
