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// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.
//go:build darwin && !kqueue && cgo
// +build darwin,!kqueue,cgo
package notify
/*
#include <CoreServices/CoreServices.h>
#include <dispatch/dispatch.h>
void gostream(uintptr_t, uintptr_t, size_t, uintptr_t, uintptr_t, uintptr_t);
static FSEventStreamRef EventStreamCreate(FSEventStreamContext * context, uintptr_t info, CFArrayRef paths, FSEventStreamEventId since, CFTimeInterval latency, FSEventStreamCreateFlags flags) {
context->info = (void*) info;
return FSEventStreamCreate(NULL, (FSEventStreamCallback) gostream, context, paths, since, latency, flags);
}
#cgo LDFLAGS: -framework CoreServices
*/
import "C"
import (
"errors"
"os"
"sync"
"sync/atomic"
"unsafe"
)
var nilstream C.FSEventStreamRef
// Default arguments for FSEventStreamCreate function.
var (
latency C.CFTimeInterval
flags = C.FSEventStreamCreateFlags(C.kFSEventStreamCreateFlagFileEvents | C.kFSEventStreamCreateFlagNoDefer)
since = uint64(C.FSEventsGetCurrentEventId())
)
// global dispatch queue which all streams are registered with
var q C.dispatch_queue_t = C.dispatch_queue_create(
C.CString("com.github.rjeczalik.notify"),
(C.dispatch_queue_attr_t)(C.DISPATCH_QUEUE_SERIAL),
)
// Errors returned when FSEvents functions fail.
var (
errCreate = os.NewSyscallError("FSEventStreamCreate", errors.New("NULL"))
errStart = os.NewSyscallError("FSEventStreamStart", errors.New("false"))
)
//export gostream
func gostream(_, info uintptr, n C.size_t, paths, flags, ids uintptr) {
const (
offchar = unsafe.Sizeof((*C.char)(nil))
offflag = unsafe.Sizeof(C.FSEventStreamEventFlags(0))
offid = unsafe.Sizeof(C.FSEventStreamEventId(0))
)
if n == 0 {
return
}
fn := streamFuncs.get(info)
if fn == nil {
return
}
ev := make([]FSEvent, 0, int(n))
for i := uintptr(0); i < uintptr(n); i++ {
switch flags := *(*uint32)(unsafe.Pointer((flags + i*offflag))); {
case flags&uint32(FSEventsEventIdsWrapped) != 0:
atomic.StoreUint64(&since, uint64(C.FSEventsGetCurrentEventId()))
default:
ev = append(ev, FSEvent{
Path: C.GoString(*(**C.char)(unsafe.Pointer(paths + i*offchar))),
Flags: flags,
ID: *(*uint64)(unsafe.Pointer(ids + i*offid)),
})
}
}
fn(ev)
}
// StreamFunc is a callback called when stream receives file events.
type streamFunc func([]FSEvent)
var streamFuncs = streamFuncRegistry{m: map[uintptr]streamFunc{}}
type streamFuncRegistry struct {
mu sync.Mutex
m map[uintptr]streamFunc
i uintptr
}
func (r *streamFuncRegistry) get(id uintptr) streamFunc {
r.mu.Lock()
defer r.mu.Unlock()
return r.m[id]
}
func (r *streamFuncRegistry) add(fn streamFunc) uintptr {
r.mu.Lock()
defer r.mu.Unlock()
r.i++
r.m[r.i] = fn
return r.i
}
func (r *streamFuncRegistry) delete(id uintptr) {
r.mu.Lock()
defer r.mu.Unlock()
delete(r.m, id)
}
// Stream represents a single watch-point which listens for events scheduled on the global dispatch queue.
type stream struct {
path string
ref C.FSEventStreamRef
info uintptr
}
// NewStream creates a stream for given path, listening for file events and
// calling fn upon receiving any.
func newStream(path string, fn streamFunc) *stream {
return &stream{
path: path,
info: streamFuncs.add(fn),
}
}
// Start creates a FSEventStream for the given path and schedules on the global dispatch queue.
// It's a nop if the stream was already started.
func (s *stream) Start() error {
if s.ref != nilstream {
return nil
}
p := C.CFStringCreateWithCStringNoCopy(C.kCFAllocatorDefault, C.CString(s.path), C.kCFStringEncodingUTF8, C.kCFAllocatorDefault)
path := C.CFArrayCreate(C.kCFAllocatorDefault, (*unsafe.Pointer)(unsafe.Pointer(&p)), 1, nil)
ctx := C.FSEventStreamContext{}
ref := C.EventStreamCreate(&ctx, C.uintptr_t(s.info), path, C.FSEventStreamEventId(atomic.LoadUint64(&since)), latency, flags)
if ref == nilstream {
return errCreate
}
C.FSEventStreamSetDispatchQueue(ref, q)
if C.FSEventStreamStart(ref) == C.Boolean(0) {
C.FSEventStreamInvalidate(ref)
return errStart
}
s.ref = ref
return nil
}
// Stop stops underlying FSEventStream and unregisters it from the global dispatch queue.
func (s *stream) Stop() {
if s.ref == nilstream {
return
}
C.FSEventStreamStop(s.ref)
C.FSEventStreamInvalidate(s.ref)
s.ref = nilstream
streamFuncs.delete(s.info)
}
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