1 files changed, 523 insertions, 0 deletions

diff --git a/compat/fsmonitor/fsm-listen-darwin.c b/compat/fsmonitor/fsm-listen-darwin.c
new file mode 100644
index 0000000..cc9af1e
--- /dev/null
+++ b/compat/fsmonitor/fsm-listen-darwin.c
@@ -0,0 +1,523 @@
+#ifndef __clang__
+#include "fsm-darwin-gcc.h"
+#else
+#include <CoreFoundation/CoreFoundation.h>
+#include <CoreServices/CoreServices.h>
+
+#ifndef AVAILABLE_MAC_OS_X_VERSION_10_13_AND_LATER
+/*
+ * This enum value was added in 10.13 to:
+ *
+ * /Applications/Xcode.app/Contents/Developer/Platforms/ \
+ *    MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/ \
+ *    Library/Frameworks/CoreServices.framework/Frameworks/ \
+ *    FSEvents.framework/Versions/Current/Headers/FSEvents.h
+ *
+ * If we're compiling against an older SDK, this symbol won't be
+ * present.  Silently define it here so that we don't have to ifdef
+ * the logging or masking below.  This should be harmless since older
+ * versions of macOS won't ever emit this FS event anyway.
+ */
+#define kFSEventStreamEventFlagItemCloned         0x00400000
+#endif
+#endif
+
+#include "cache.h"
+#include "fsmonitor.h"
+#include "fsm-listen.h"
+#include "fsmonitor--daemon.h"
+#include "fsmonitor-path-utils.h"
+
+struct fsm_listen_data
+{
+	CFStringRef cfsr_worktree_path;
+	CFStringRef cfsr_gitdir_path;
+
+	CFArrayRef cfar_paths_to_watch;
+	int nr_paths_watching;
+
+	FSEventStreamRef stream;
+
+	CFRunLoopRef rl;
+
+	enum shutdown_style {
+		SHUTDOWN_EVENT = 0,
+		FORCE_SHUTDOWN,
+		FORCE_ERROR_STOP,
+	} shutdown_style;
+
+	unsigned int stream_scheduled:1;
+	unsigned int stream_started:1;
+};
+
+static void log_flags_set(const char *path, const FSEventStreamEventFlags flag)
+{
+	struct strbuf msg = STRBUF_INIT;
+
+	if (flag & kFSEventStreamEventFlagMustScanSubDirs)
+		strbuf_addstr(&msg, "MustScanSubDirs|");
+	if (flag & kFSEventStreamEventFlagUserDropped)
+		strbuf_addstr(&msg, "UserDropped|");
+	if (flag & kFSEventStreamEventFlagKernelDropped)
+		strbuf_addstr(&msg, "KernelDropped|");
+	if (flag & kFSEventStreamEventFlagEventIdsWrapped)
+		strbuf_addstr(&msg, "EventIdsWrapped|");
+	if (flag & kFSEventStreamEventFlagHistoryDone)
+		strbuf_addstr(&msg, "HistoryDone|");
+	if (flag & kFSEventStreamEventFlagRootChanged)
+		strbuf_addstr(&msg, "RootChanged|");
+	if (flag & kFSEventStreamEventFlagMount)
+		strbuf_addstr(&msg, "Mount|");
+	if (flag & kFSEventStreamEventFlagUnmount)
+		strbuf_addstr(&msg, "Unmount|");
+	if (flag & kFSEventStreamEventFlagItemChangeOwner)
+		strbuf_addstr(&msg, "ItemChangeOwner|");
+	if (flag & kFSEventStreamEventFlagItemCreated)
+		strbuf_addstr(&msg, "ItemCreated|");
+	if (flag & kFSEventStreamEventFlagItemFinderInfoMod)
+		strbuf_addstr(&msg, "ItemFinderInfoMod|");
+	if (flag & kFSEventStreamEventFlagItemInodeMetaMod)
+		strbuf_addstr(&msg, "ItemInodeMetaMod|");
+	if (flag & kFSEventStreamEventFlagItemIsDir)
+		strbuf_addstr(&msg, "ItemIsDir|");
+	if (flag & kFSEventStreamEventFlagItemIsFile)
+		strbuf_addstr(&msg, "ItemIsFile|");
+	if (flag & kFSEventStreamEventFlagItemIsHardlink)
+		strbuf_addstr(&msg, "ItemIsHardlink|");
+	if (flag & kFSEventStreamEventFlagItemIsLastHardlink)
+		strbuf_addstr(&msg, "ItemIsLastHardlink|");
+	if (flag & kFSEventStreamEventFlagItemIsSymlink)
+		strbuf_addstr(&msg, "ItemIsSymlink|");
+	if (flag & kFSEventStreamEventFlagItemModified)
+		strbuf_addstr(&msg, "ItemModified|");
+	if (flag & kFSEventStreamEventFlagItemRemoved)
+		strbuf_addstr(&msg, "ItemRemoved|");
+	if (flag & kFSEventStreamEventFlagItemRenamed)
+		strbuf_addstr(&msg, "ItemRenamed|");
+	if (flag & kFSEventStreamEventFlagItemXattrMod)
+		strbuf_addstr(&msg, "ItemXattrMod|");
+	if (flag & kFSEventStreamEventFlagOwnEvent)
+		strbuf_addstr(&msg, "OwnEvent|");
+	if (flag & kFSEventStreamEventFlagItemCloned)
+		strbuf_addstr(&msg, "ItemCloned|");
+
+	trace_printf_key(&trace_fsmonitor, "fsevent: '%s', flags=0x%x %s",
+			 path, flag, msg.buf);
+
+	strbuf_release(&msg);
+}
+
+static int ef_is_root_changed(const FSEventStreamEventFlags ef)
+{
+	return (ef & kFSEventStreamEventFlagRootChanged);
+}
+
+static int ef_is_root_delete(const FSEventStreamEventFlags ef)
+{
+	return (ef & kFSEventStreamEventFlagItemIsDir &&
+		ef & kFSEventStreamEventFlagItemRemoved);
+}
+
+static int ef_is_root_renamed(const FSEventStreamEventFlags ef)
+{
+	return (ef & kFSEventStreamEventFlagItemIsDir &&
+		ef & kFSEventStreamEventFlagItemRenamed);
+}
+
+static int ef_is_dropped(const FSEventStreamEventFlags ef)
+{
+	return (ef & kFSEventStreamEventFlagMustScanSubDirs ||
+		ef & kFSEventStreamEventFlagKernelDropped ||
+		ef & kFSEventStreamEventFlagUserDropped);
+}
+
+/*
+ * If an `xattr` change is the only reason we received this event,
+ * then silently ignore it.  Git doesn't care about xattr's.  We
+ * have to be careful here because the kernel can combine multiple
+ * events for a single path.  And because events always have certain
+ * bits set, such as `ItemIsFile` or `ItemIsDir`.
+ *
+ * Return 1 if we should ignore it.
+ */
+static int ef_ignore_xattr(const FSEventStreamEventFlags ef)
+{
+	static const FSEventStreamEventFlags mask =
+		kFSEventStreamEventFlagItemChangeOwner |
+		kFSEventStreamEventFlagItemCreated |
+		kFSEventStreamEventFlagItemFinderInfoMod |
+		kFSEventStreamEventFlagItemInodeMetaMod |
+		kFSEventStreamEventFlagItemModified |
+		kFSEventStreamEventFlagItemRemoved |
+		kFSEventStreamEventFlagItemRenamed |
+		kFSEventStreamEventFlagItemXattrMod |
+		kFSEventStreamEventFlagItemCloned;
+
+	return ((ef & mask) == kFSEventStreamEventFlagItemXattrMod);
+}
+
+/*
+ * On MacOS we have to adjust for Unicode composition insensitivity
+ * (where NFC and NFD spellings are not respected).  The different
+ * spellings are essentially aliases regardless of how the path is
+ * actually stored on the disk.
+ *
+ * This is related to "core.precomposeUnicode" (which wants to try
+ * to hide NFD completely and treat everything as NFC).  Here, we
+ * don't know what the value the client has (or will have) for this
+ * config setting when they make a query, so assume the worst and
+ * emit both when the OS gives us an NFD path.
+ */
+static void my_add_path(struct fsmonitor_batch *batch, const char *path)
+{
+	char *composed;
+
+	/* add the NFC or NFD path as received from the OS */
+	fsmonitor_batch__add_path(batch, path);
+
+	/* if NFD, also add the corresponding NFC spelling */
+	composed = (char *)precompose_string_if_needed(path);
+	if (!composed || composed == path)
+		return;
+
+	fsmonitor_batch__add_path(batch, composed);
+	free(composed);
+}
+
+
+static void fsevent_callback(ConstFSEventStreamRef streamRef,
+			     void *ctx,
+			     size_t num_of_events,
+			     void *event_paths,
+			     const FSEventStreamEventFlags event_flags[],
+			     const FSEventStreamEventId event_ids[])
+{
+	struct fsmonitor_daemon_state *state = ctx;
+	struct fsm_listen_data *data = state->listen_data;
+	char **paths = (char **)event_paths;
+	struct fsmonitor_batch *batch = NULL;
+	struct string_list cookie_list = STRING_LIST_INIT_DUP;
+	const char *path_k;
+	const char *slash;
+	char *resolved = NULL;
+	struct strbuf tmp = STRBUF_INIT;
+	int k;
+
+	/*
+	 * Build a list of all filesystem changes into a private/local
+	 * list and without holding any locks.
+	 */
+	for (k = 0; k < num_of_events; k++) {
+		/*
+		 * On Mac, we receive an array of absolute paths.
+		 */
+		free(resolved);
+		resolved = fsmonitor__resolve_alias(paths[k], &state->alias);
+		if (resolved)
+			path_k = resolved;
+		else
+			path_k = paths[k];
+
+		/*
+		 * If you want to debug FSEvents, log them to GIT_TRACE_FSMONITOR.
+		 * Please don't log them to Trace2.
+		 *
+		 * trace_printf_key(&trace_fsmonitor, "Path: '%s'", path_k);
+		 */
+
+		/*
+		 * If event[k] is marked as dropped, we assume that we have
+		 * lost sync with the filesystem and should flush our cached
+		 * data.  We need to:
+		 *
+		 * [1] Abort/wake any client threads waiting for a cookie and
+		 *     flush the cached state data (the current token), and
+		 *     create a new token.
+		 *
+		 * [2] Discard the batch that we were locally building (since
+		 *     they are conceptually relative to the just flushed
+		 *     token).
+		 */
+		if (ef_is_dropped(event_flags[k])) {
+			if (trace_pass_fl(&trace_fsmonitor))
+				log_flags_set(path_k, event_flags[k]);
+
+			fsmonitor_force_resync(state);
+			fsmonitor_batch__free_list(batch);
+			string_list_clear(&cookie_list, 0);
+			batch = NULL;
+
+			/*
+			 * We assume that any events that we received
+			 * in this callback after this dropped event
+			 * may still be valid, so we continue rather
+			 * than break.  (And just in case there is a
+			 * delete of ".git" hiding in there.)
+			 */
+			continue;
+		}
+
+		if (ef_is_root_changed(event_flags[k])) {
+			/*
+			 * The spelling of the pathname of the root directory
+			 * has changed.  This includes the name of the root
+			 * directory itself or of any parent directory in the
+			 * path.
+			 *
+			 * (There may be other conditions that throw this,
+			 * but I couldn't find any information on it.)
+			 *
+			 * Force a shutdown now and avoid things getting
+			 * out of sync.  The Unix domain socket is inside
+			 * the .git directory and a spelling change will make
+			 * it hard for clients to rendezvous with us.
+			 */
+			trace_printf_key(&trace_fsmonitor,
+					 "event: root changed");
+			goto force_shutdown;
+		}
+
+		if (ef_ignore_xattr(event_flags[k])) {
+			trace_printf_key(&trace_fsmonitor,
+					 "ignore-xattr: '%s', flags=0x%x",
+					 path_k, event_flags[k]);
+			continue;
+		}
+
+		switch (fsmonitor_classify_path_absolute(state, path_k)) {
+
+		case IS_INSIDE_DOT_GIT_WITH_COOKIE_PREFIX:
+		case IS_INSIDE_GITDIR_WITH_COOKIE_PREFIX:
+			/* special case cookie files within .git or gitdir */
+
+			/* Use just the filename of the cookie file. */
+			slash = find_last_dir_sep(path_k);
+			string_list_append(&cookie_list,
+					   slash ? slash + 1 : path_k);
+			break;
+
+		case IS_INSIDE_DOT_GIT:
+		case IS_INSIDE_GITDIR:
+			/* ignore all other paths inside of .git or gitdir */
+			break;
+
+		case IS_DOT_GIT:
+		case IS_GITDIR:
+			/*
+			 * If .git directory is deleted or renamed away,
+			 * we have to quit.
+			 */
+			if (ef_is_root_delete(event_flags[k])) {
+				trace_printf_key(&trace_fsmonitor,
+						 "event: gitdir removed");
+				goto force_shutdown;
+			}
+			if (ef_is_root_renamed(event_flags[k])) {
+				trace_printf_key(&trace_fsmonitor,
+						 "event: gitdir renamed");
+				goto force_shutdown;
+			}
+			break;
+
+		case IS_WORKDIR_PATH:
+			/* try to queue normal pathnames */
+
+			if (trace_pass_fl(&trace_fsmonitor))
+				log_flags_set(path_k, event_flags[k]);
+
+			/*
+			 * Because of the implicit "binning" (the
+			 * kernel calls us at a given frequency) and
+			 * de-duping (the kernel is free to combine
+			 * multiple events for a given pathname), an
+			 * individual fsevent could be marked as both
+			 * a file and directory.  Add it to the queue
+			 * with both spellings so that the client will
+			 * know how much to invalidate/refresh.
+			 */
+
+			if (event_flags[k] & (kFSEventStreamEventFlagItemIsFile | kFSEventStreamEventFlagItemIsSymlink)) {
+				const char *rel = path_k +
+					state->path_worktree_watch.len + 1;
+
+				if (!batch)
+					batch = fsmonitor_batch__new();
+				my_add_path(batch, rel);
+			}
+
+			if (event_flags[k] & kFSEventStreamEventFlagItemIsDir) {
+				const char *rel = path_k +
+					state->path_worktree_watch.len + 1;
+
+				strbuf_reset(&tmp);
+				strbuf_addstr(&tmp, rel);
+				strbuf_addch(&tmp, '/');
+
+				if (!batch)
+					batch = fsmonitor_batch__new();
+				my_add_path(batch, tmp.buf);
+			}
+
+			break;
+
+		case IS_OUTSIDE_CONE:
+		default:
+			trace_printf_key(&trace_fsmonitor,
+					 "ignoring '%s'", path_k);
+			break;
+		}
+	}
+
+	free(resolved);
+	fsmonitor_publish(state, batch, &cookie_list);
+	string_list_clear(&cookie_list, 0);
+	strbuf_release(&tmp);
+	return;
+
+force_shutdown:
+	free(resolved);
+	fsmonitor_batch__free_list(batch);
+	string_list_clear(&cookie_list, 0);
+
+	data->shutdown_style = FORCE_SHUTDOWN;
+	CFRunLoopStop(data->rl);
+	strbuf_release(&tmp);
+	return;
+}
+
+/*
+ * In the call to `FSEventStreamCreate()` to setup our watch, the
+ * `latency` argument determines the frequency of calls to our callback
+ * with new FS events.  Too slow and events get dropped; too fast and
+ * we burn CPU unnecessarily.  Since it is rather obscure, I don't
+ * think this needs to be a config setting.  I've done extensive
+ * testing on my systems and chosen the value below.  It gives good
+ * results and I've not seen any dropped events.
+ *
+ * With a latency of 0.1, I was seeing lots of dropped events during
+ * the "touch 100000" files test within t/perf/p7519, but with a
+ * latency of 0.001 I did not see any dropped events.  So I'm going
+ * to assume that this is the "correct" value.
+ *
+ * https://developer.apple.com/documentation/coreservices/1443980-fseventstreamcreate
+ */
+
+int fsm_listen__ctor(struct fsmonitor_daemon_state *state)
+{
+	FSEventStreamCreateFlags flags = kFSEventStreamCreateFlagNoDefer |
+		kFSEventStreamCreateFlagWatchRoot |
+		kFSEventStreamCreateFlagFileEvents;
+	FSEventStreamContext ctx = {
+		0,
+		state,
+		NULL,
+		NULL,
+		NULL
+	};
+	struct fsm_listen_data *data;
+	const void *dir_array[2];
+
+	CALLOC_ARRAY(data, 1);
+	state->listen_data = data;
+
+	data->cfsr_worktree_path = CFStringCreateWithCString(
+		NULL, state->path_worktree_watch.buf, kCFStringEncodingUTF8);
+	dir_array[data->nr_paths_watching++] = data->cfsr_worktree_path;
+
+	if (state->nr_paths_watching > 1) {
+		data->cfsr_gitdir_path = CFStringCreateWithCString(
+			NULL, state->path_gitdir_watch.buf,
+			kCFStringEncodingUTF8);
+		dir_array[data->nr_paths_watching++] = data->cfsr_gitdir_path;
+	}
+
+	data->cfar_paths_to_watch = CFArrayCreate(NULL, dir_array,
+						  data->nr_paths_watching,
+						  NULL);
+	data->stream = FSEventStreamCreate(NULL, fsevent_callback, &ctx,
+					   data->cfar_paths_to_watch,
+					   kFSEventStreamEventIdSinceNow,
+					   0.001, flags);
+	if (!data->stream)
+		goto failed;
+
+	/*
+	 * `data->rl` needs to be set inside the listener thread.
+	 */
+
+	return 0;
+
+failed:
+	error(_("Unable to create FSEventStream."));
+
+	FREE_AND_NULL(state->listen_data);
+	return -1;
+}
+
+void fsm_listen__dtor(struct fsmonitor_daemon_state *state)
+{
+	struct fsm_listen_data *data;
+
+	if (!state || !state->listen_data)
+		return;
+
+	data = state->listen_data;
+
+	if (data->stream) {
+		if (data->stream_started)
+			FSEventStreamStop(data->stream);
+		if (data->stream_scheduled)
+			FSEventStreamInvalidate(data->stream);
+		FSEventStreamRelease(data->stream);
+	}
+
+	FREE_AND_NULL(state->listen_data);
+}
+
+void fsm_listen__stop_async(struct fsmonitor_daemon_state *state)
+{
+	struct fsm_listen_data *data;
+
+	data = state->listen_data;
+	data->shutdown_style = SHUTDOWN_EVENT;
+
+	CFRunLoopStop(data->rl);
+}
+
+void fsm_listen__loop(struct fsmonitor_daemon_state *state)
+{
+	struct fsm_listen_data *data;
+
+	data = state->listen_data;
+
+	data->rl = CFRunLoopGetCurrent();
+
+	FSEventStreamScheduleWithRunLoop(data->stream, data->rl, kCFRunLoopDefaultMode);
+	data->stream_scheduled = 1;
+
+	if (!FSEventStreamStart(data->stream)) {
+		error(_("Failed to start the FSEventStream"));
+		goto force_error_stop_without_loop;
+	}
+	data->stream_started = 1;
+
+	CFRunLoopRun();
+
+	switch (data->shutdown_style) {
+	case FORCE_ERROR_STOP:
+		state->listen_error_code = -1;
+		/* fall thru */
+	case FORCE_SHUTDOWN:
+		ipc_server_stop_async(state->ipc_server_data);
+		/* fall thru */
+	case SHUTDOWN_EVENT:
+	default:
+		break;
+	}
+	return;
+
+force_error_stop_without_loop:
+	state->listen_error_code = -1;
+	ipc_server_stop_async(state->ipc_server_data);
+	return;
+}