@@ -907,6 +907,7 @@ LIB_OBJS += fetch-pack.o
LIB_OBJS += fmt-merge-msg.o
LIB_OBJS += fsck.o
LIB_OBJS += fsmonitor.o
+LIB_OBJS += fsmonitor-ipc.o
LIB_OBJS += gettext.o
LIB_OBJS += gpg-interface.o
LIB_OBJS += graph.o
new file mode 100644
@@ -0,0 +1,171 @@
+#include "cache.h"
+#include "fsmonitor.h"
+#include "simple-ipc.h"
+#include "fsmonitor-ipc.h"
+#include "run-command.h"
+#include "strbuf.h"
+#include "trace2.h"
+
+#ifndef HAVE_FSMONITOR_DAEMON_BACKEND
+
+/*
+ * A trivial implementation of the fsmonitor_ipc__ API for unsupported
+ * platforms.
+ */
+
+int fsmonitor_ipc__is_supported(void)
+{
+ return 0;
+}
+
+const char *fsmonitor_ipc__get_path(void)
+{
+ return NULL;
+}
+
+enum ipc_active_state fsmonitor_ipc__get_state(void)
+{
+ return IPC_STATE__OTHER_ERROR;
+}
+
+int fsmonitor_ipc__send_query(const char *since_token,
+ struct strbuf *answer)
+{
+ return -1;
+}
+
+int fsmonitor_ipc__send_command(const char *command,
+ struct strbuf *answer)
+{
+ return -1;
+}
+
+#else
+
+int fsmonitor_ipc__is_supported(void)
+{
+ return 1;
+}
+
+GIT_PATH_FUNC(fsmonitor_ipc__get_path, "fsmonitor--daemon.ipc")
+
+enum ipc_active_state fsmonitor_ipc__get_state(void)
+{
+ return ipc_get_active_state(fsmonitor_ipc__get_path());
+}
+
+static int spawn_daemon(void)
+{
+ const char *args[] = { "fsmonitor--daemon", "start", NULL };
+
+ return run_command_v_opt_tr2(args, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD,
+ "fsmonitor");
+}
+
+int fsmonitor_ipc__send_query(const char *since_token,
+ struct strbuf *answer)
+{
+ int ret = -1;
+ int tried_to_spawn = 0;
+ enum ipc_active_state state = IPC_STATE__OTHER_ERROR;
+ struct ipc_client_connection *connection = NULL;
+ struct ipc_client_connect_options options
+ = IPC_CLIENT_CONNECT_OPTIONS_INIT;
+ const char *tok = since_token ? since_token : "";
+ size_t tok_len = since_token ? strlen(since_token) : 0;
+
+ options.wait_if_busy = 1;
+ options.wait_if_not_found = 0;
+
+ trace2_region_enter("fsm_client", "query", NULL);
+ trace2_data_string("fsm_client", NULL, "query/command", tok);
+
+try_again:
+ state = ipc_client_try_connect(fsmonitor_ipc__get_path(), &options,
+ &connection);
+
+ switch (state) {
+ case IPC_STATE__LISTENING:
+ ret = ipc_client_send_command_to_connection(
+ connection, tok, tok_len, answer);
+ ipc_client_close_connection(connection);
+
+ trace2_data_intmax("fsm_client", NULL,
+ "query/response-length", answer->len);
+ goto done;
+
+ case IPC_STATE__NOT_LISTENING:
+ case IPC_STATE__PATH_NOT_FOUND:
+ if (tried_to_spawn)
+ goto done;
+
+ tried_to_spawn++;
+ if (spawn_daemon())
+ goto done;
+
+ /*
+ * Try again, but this time give the daemon a chance to
+ * actually create the pipe/socket.
+ *
+ * Granted, the daemon just started so it can't possibly have
+ * any FS cached yet, so we'll always get a trivial answer.
+ * BUT the answer should include a new token that can serve
+ * as the basis for subsequent requests.
+ */
+ options.wait_if_not_found = 1;
+ goto try_again;
+
+ case IPC_STATE__INVALID_PATH:
+ ret = error(_("fsmonitor_ipc__send_query: invalid path '%s'"),
+ fsmonitor_ipc__get_path());
+ goto done;
+
+ case IPC_STATE__OTHER_ERROR:
+ default:
+ ret = error(_("fsmonitor_ipc__send_query: unspecified error on '%s'"),
+ fsmonitor_ipc__get_path());
+ goto done;
+ }
+
+done:
+ trace2_region_leave("fsm_client", "query", NULL);
+
+ return ret;
+}
+
+int fsmonitor_ipc__send_command(const char *command,
+ struct strbuf *answer)
+{
+ struct ipc_client_connection *connection = NULL;
+ struct ipc_client_connect_options options
+ = IPC_CLIENT_CONNECT_OPTIONS_INIT;
+ int ret;
+ enum ipc_active_state state;
+ const char *c = command ? command : "";
+ size_t c_len = command ? strlen(command) : 0;
+
+ strbuf_reset(answer);
+
+ options.wait_if_busy = 1;
+ options.wait_if_not_found = 0;
+
+ state = ipc_client_try_connect(fsmonitor_ipc__get_path(), &options,
+ &connection);
+ if (state != IPC_STATE__LISTENING) {
+ die("fsmonitor--daemon is not running");
+ return -1;
+ }
+
+ ret = ipc_client_send_command_to_connection(connection, c, c_len,
+ answer);
+ ipc_client_close_connection(connection);
+
+ if (ret == -1) {
+ die("could not send '%s' command to fsmonitor--daemon", c);
+ return -1;
+ }
+
+ return 0;
+}
+
+#endif
new file mode 100644
@@ -0,0 +1,48 @@
+#ifndef FSMONITOR_IPC_H
+#define FSMONITOR_IPC_H
+
+#include "simple-ipc.h"
+
+/*
+ * Returns true if built-in file system monitor daemon is defined
+ * for this platform.
+ */
+int fsmonitor_ipc__is_supported(void);
+
+/*
+ * Returns the pathname to the IPC named pipe or Unix domain socket
+ * where a `git-fsmonitor--daemon` process will listen. This is a
+ * per-worktree value.
+ *
+ * Returns NULL if the daemon is not supported on this platform.
+ */
+const char *fsmonitor_ipc__get_path(void);
+
+/*
+ * Try to determine whether there is a `git-fsmonitor--daemon` process
+ * listening on the IPC pipe/socket.
+ */
+enum ipc_active_state fsmonitor_ipc__get_state(void);
+
+/*
+ * Connect to a `git-fsmonitor--daemon` process via simple-ipc
+ * and ask for the set of changed files since the given token.
+ *
+ * Spawn a daemon process in the background if necessary.
+ *
+ * Returns -1 on error; 0 on success.
+ */
+int fsmonitor_ipc__send_query(const char *since_token,
+ struct strbuf *answer);
+
+/*
+ * Connect to a `git-fsmonitor--daemon` process via simple-ipc and
+ * send a command verb. If no daemon is available, we DO NOT try to
+ * start one.
+ *
+ * Returns -1 on error; 0 on success.
+ */
+int fsmonitor_ipc__send_command(const char *command,
+ struct strbuf *answer);
+
+#endif /* FSMONITOR_IPC_H */