1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
|
// 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.
// +build darwin,!kqueue
package notify
/*
#include <CoreServices/CoreServices.h>
typedef void (*CFRunLoopPerformCallBack)(void*);
void gosource(void *);
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"
"time"
"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())
)
var runloop C.CFRunLoopRef // global runloop which all streams are registered with
var wg sync.WaitGroup // used to wait until the runloop starts
// source is used for synchronization purposes - it signals when runloop has
// started and is ready via the wg. It also serves purpose of a dummy source,
// thanks to it the runloop does not return as it also has at least one source
// registered.
var source = C.CFRunLoopSourceCreate(nil, 0, &C.CFRunLoopSourceContext{
perform: (C.CFRunLoopPerformCallBack)(C.gosource),
})
// Errors returned when FSEvents functions fail.
var (
errCreate = os.NewSyscallError("FSEventStreamCreate", errors.New("NULL"))
errStart = os.NewSyscallError("FSEventStreamStart", errors.New("false"))
)
// initializes the global runloop and ensures any created stream awaits its
// readiness.
func init() {
wg.Add(1)
go func() {
runloop = C.CFRunLoopGetCurrent()
C.CFRunLoopAddSource(runloop, source, C.kCFRunLoopDefaultMode)
C.CFRunLoopRun()
panic("runloop has just unexpectedly stopped")
}()
C.CFRunLoopSourceSignal(source)
}
//export gosource
func gosource(unsafe.Pointer) {
time.Sleep(time.Second)
wg.Done()
}
//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
}
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)),
})
}
}
streamFuncs.get(info)(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 single watch-point which listens for events scheduled by
// the global runloop.
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 receving 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 it with
// global runloop. It's a nop if the stream was already started.
func (s *stream) Start() error {
if s.ref != nilstream {
return nil
}
wg.Wait()
p := C.CFStringCreateWithCStringNoCopy(nil, C.CString(s.path), C.kCFStringEncodingUTF8, nil)
path := C.CFArrayCreate(nil, (*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.FSEventStreamScheduleWithRunLoop(ref, runloop, C.kCFRunLoopDefaultMode)
if C.FSEventStreamStart(ref) == C.Boolean(0) {
C.FSEventStreamInvalidate(ref)
return errStart
}
C.CFRunLoopWakeUp(runloop)
s.ref = ref
return nil
}
// Stop stops underlying FSEventStream and unregisters it from global runloop.
func (s *stream) Stop() {
if s.ref == nilstream {
return
}
wg.Wait()
C.FSEventStreamStop(s.ref)
C.FSEventStreamInvalidate(s.ref)
C.CFRunLoopWakeUp(runloop)
s.ref = nilstream
streamFuncs.delete(s.info)
}
|
