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git/compat/fsmonitor/fsm-listen-darwin.c

513 lines
14 KiB

#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"
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;
int k;
struct strbuf tmp = STRBUF_INIT;
/*
* 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.
*/
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);
/*
* 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) {
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;
}
}
fsmonitor_publish(state, batch, &cookie_list);
string_list_clear(&cookie_list, 0);
strbuf_release(&tmp);
return;
force_shutdown:
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;
}