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
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
|
#include "main_thread_interface.h"
#include "node_mutex.h"
#include "v8-inspector.h"
#include <functional>
#include <unicode/unistr.h>
namespace node {
namespace inspector {
namespace {
using v8_inspector::StringView;
using v8_inspector::StringBuffer;
template <typename T>
class DeletableWrapper : public Deletable {
public:
explicit DeletableWrapper(std::unique_ptr<T> object)
: object_(std::move(object)) {}
~DeletableWrapper() override = default;
static T* get(MainThreadInterface* thread, int id) {
return
static_cast<DeletableWrapper<T>*>(thread->GetObject(id))->object_.get();
}
private:
std::unique_ptr<T> object_;
};
template <typename T>
std::unique_ptr<Deletable> WrapInDeletable(std::unique_ptr<T> object) {
return std::unique_ptr<DeletableWrapper<T>>(
new DeletableWrapper<T>(std::move(object)));
}
template <typename Factory>
class CreateObjectRequest : public Request {
public:
CreateObjectRequest(int object_id, Factory factory)
: object_id_(object_id), factory_(std::move(factory)) {}
void Call(MainThreadInterface* thread) {
thread->AddObject(object_id_, WrapInDeletable(factory_(thread)));
}
private:
int object_id_;
Factory factory_;
};
template <typename Factory>
std::unique_ptr<Request> NewCreateRequest(int object_id, Factory factory) {
return std::unique_ptr<Request>(
new CreateObjectRequest<Factory>(object_id, std::move(factory)));
}
class DeleteRequest : public Request {
public:
explicit DeleteRequest(int object_id) : object_id_(object_id) {}
void Call(MainThreadInterface* thread) override {
thread->RemoveObject(object_id_);
}
private:
int object_id_;
};
template <typename Target, typename Fn>
class CallRequest : public Request {
public:
CallRequest(int id, Fn fn) : id_(id), fn_(std::move(fn)) {}
void Call(MainThreadInterface* thread) override {
fn_(DeletableWrapper<Target>::get(thread, id_));
}
private:
int id_;
Fn fn_;
};
class DispatchMessagesTask : public v8::Task {
public:
explicit DispatchMessagesTask(MainThreadInterface* thread)
: thread_(thread) {}
void Run() override {
thread_->DispatchMessages();
}
private:
MainThreadInterface* thread_;
};
void DisposePairCallback(uv_handle_t* ref) {
using AsyncAndInterface = std::pair<uv_async_t, MainThreadInterface*>;
AsyncAndInterface* pair = node::ContainerOf(
&AsyncAndInterface::first, reinterpret_cast<uv_async_t*>(ref));
delete pair;
}
template <typename T>
class AnotherThreadObjectReference {
public:
AnotherThreadObjectReference(
std::shared_ptr<MainThreadHandle> thread, int object_id)
: thread_(thread), object_id_(object_id) {}
template <typename Factory>
AnotherThreadObjectReference(
std::shared_ptr<MainThreadHandle> thread, Factory factory)
: AnotherThreadObjectReference(thread, thread->newObjectId()) {
thread_->Post(NewCreateRequest(object_id_, std::move(factory)));
}
AnotherThreadObjectReference(AnotherThreadObjectReference&) = delete;
~AnotherThreadObjectReference() {
// Disappearing thread may cause a memory leak
thread_->Post(
std::unique_ptr<DeleteRequest>(new DeleteRequest(object_id_)));
}
template <typename Fn>
void Call(Fn fn) const {
using Request = CallRequest<T, Fn>;
thread_->Post(std::unique_ptr<Request>(
new Request(object_id_, std::move(fn))));
}
template <typename Arg>
void Call(void (T::*fn)(Arg), Arg argument) const {
Call(std::bind(Apply<Arg>, std::placeholders::_1, fn, std::move(argument)));
}
private:
// This has to use non-const reference to support std::bind with non-copyable
// types
template <typename Argument>
static void Apply(T* target, void (T::*fn)(Argument),
/* NOLINT (runtime/references) */ Argument& argument) {
(target->*fn)(std::move(argument));
}
std::shared_ptr<MainThreadHandle> thread_;
const int object_id_;
};
class MainThreadSessionState {
public:
MainThreadSessionState(MainThreadInterface* thread, bool prevent_shutdown)
: thread_(thread),
prevent_shutdown_(prevent_shutdown) {}
static std::unique_ptr<MainThreadSessionState> Create(
MainThreadInterface* thread, bool prevent_shutdown) {
return std::unique_ptr<MainThreadSessionState>(
new MainThreadSessionState(thread, prevent_shutdown));
}
void Connect(std::unique_ptr<InspectorSessionDelegate> delegate) {
Agent* agent = thread_->inspector_agent();
if (agent != nullptr)
session_ = agent->Connect(std::move(delegate), prevent_shutdown_);
}
void Dispatch(std::unique_ptr<StringBuffer> message) {
session_->Dispatch(message->string());
}
private:
MainThreadInterface* thread_;
bool prevent_shutdown_;
std::unique_ptr<InspectorSession> session_;
};
class CrossThreadInspectorSession : public InspectorSession {
public:
CrossThreadInspectorSession(
int id,
std::shared_ptr<MainThreadHandle> thread,
std::unique_ptr<InspectorSessionDelegate> delegate,
bool prevent_shutdown)
: state_(thread, std::bind(MainThreadSessionState::Create,
std::placeholders::_1,
prevent_shutdown)) {
state_.Call(&MainThreadSessionState::Connect, std::move(delegate));
}
void Dispatch(const StringView& message) override {
state_.Call(&MainThreadSessionState::Dispatch,
StringBuffer::create(message));
}
private:
AnotherThreadObjectReference<MainThreadSessionState> state_;
};
class ThreadSafeDelegate : public InspectorSessionDelegate {
public:
ThreadSafeDelegate(std::shared_ptr<MainThreadHandle> thread, int object_id)
: thread_(thread), delegate_(thread, object_id) {}
void SendMessageToFrontend(const v8_inspector::StringView& message) override {
delegate_.Call(
[m = StringBuffer::create(message)]
(InspectorSessionDelegate* delegate) {
delegate->SendMessageToFrontend(m->string());
});
}
private:
std::shared_ptr<MainThreadHandle> thread_;
AnotherThreadObjectReference<InspectorSessionDelegate> delegate_;
};
} // namespace
MainThreadInterface::MainThreadInterface(Agent* agent, uv_loop_t* loop,
v8::Isolate* isolate,
v8::Platform* platform)
: agent_(agent), isolate_(isolate),
platform_(platform) {
main_thread_request_.reset(new AsyncAndInterface(uv_async_t(), this));
CHECK_EQ(0, uv_async_init(loop, &main_thread_request_->first,
DispatchMessagesAsyncCallback));
// Inspector uv_async_t should not prevent main loop shutdown.
uv_unref(reinterpret_cast<uv_handle_t*>(&main_thread_request_->first));
}
MainThreadInterface::~MainThreadInterface() {
if (handle_)
handle_->Reset();
}
// static
void MainThreadInterface::DispatchMessagesAsyncCallback(uv_async_t* async) {
AsyncAndInterface* asyncAndInterface =
node::ContainerOf(&AsyncAndInterface::first, async);
asyncAndInterface->second->DispatchMessages();
}
// static
void MainThreadInterface::CloseAsync(AsyncAndInterface* pair) {
uv_close(reinterpret_cast<uv_handle_t*>(&pair->first), DisposePairCallback);
}
void MainThreadInterface::Post(std::unique_ptr<Request> request) {
Mutex::ScopedLock scoped_lock(requests_lock_);
bool needs_notify = requests_.empty();
requests_.push_back(std::move(request));
if (needs_notify) {
CHECK_EQ(0, uv_async_send(&main_thread_request_->first));
if (isolate_ != nullptr && platform_ != nullptr) {
platform_->CallOnForegroundThread(isolate_,
new DispatchMessagesTask(this));
isolate_->RequestInterrupt([](v8::Isolate* isolate, void* thread) {
static_cast<MainThreadInterface*>(thread)->DispatchMessages();
}, this);
}
}
incoming_message_cond_.Broadcast(scoped_lock);
}
bool MainThreadInterface::WaitForFrontendEvent() {
// We allow DispatchMessages reentry as we enter the pause. This is important
// to support debugging the code invoked by an inspector call, such
// as Runtime.evaluate
dispatching_messages_ = false;
if (dispatching_message_queue_.empty()) {
Mutex::ScopedLock scoped_lock(requests_lock_);
while (requests_.empty()) incoming_message_cond_.Wait(scoped_lock);
}
return true;
}
void MainThreadInterface::DispatchMessages() {
if (dispatching_messages_)
return;
dispatching_messages_ = true;
bool had_messages = false;
do {
if (dispatching_message_queue_.empty()) {
Mutex::ScopedLock scoped_lock(requests_lock_);
requests_.swap(dispatching_message_queue_);
}
had_messages = !dispatching_message_queue_.empty();
while (!dispatching_message_queue_.empty()) {
MessageQueue::value_type task;
std::swap(dispatching_message_queue_.front(), task);
dispatching_message_queue_.pop_front();
task->Call(this);
}
} while (had_messages);
dispatching_messages_ = false;
}
std::shared_ptr<MainThreadHandle> MainThreadInterface::GetHandle() {
if (handle_ == nullptr)
handle_ = std::make_shared<MainThreadHandle>(this);
return handle_;
}
void MainThreadInterface::AddObject(int id,
std::unique_ptr<Deletable> object) {
CHECK_NE(nullptr, object);
managed_objects_[id] = std::move(object);
}
void MainThreadInterface::RemoveObject(int id) {
CHECK_EQ(1, managed_objects_.erase(id));
}
Deletable* MainThreadInterface::GetObject(int id) {
auto iterator = managed_objects_.find(id);
// This would mean the object is requested after it was disposed, which is
// a coding error.
CHECK_NE(managed_objects_.end(), iterator);
Deletable* pointer = iterator->second.get();
CHECK_NE(nullptr, pointer);
return pointer;
}
std::unique_ptr<StringBuffer> Utf8ToStringView(const std::string& message) {
icu::UnicodeString utf16 = icu::UnicodeString::fromUTF8(
icu::StringPiece(message.data(), message.length()));
StringView view(reinterpret_cast<const uint16_t*>(utf16.getBuffer()),
utf16.length());
return StringBuffer::create(view);
}
std::unique_ptr<InspectorSession> MainThreadHandle::Connect(
std::unique_ptr<InspectorSessionDelegate> delegate,
bool prevent_shutdown) {
return std::unique_ptr<InspectorSession>(
new CrossThreadInspectorSession(++next_session_id_,
shared_from_this(),
std::move(delegate),
prevent_shutdown));
}
bool MainThreadHandle::Post(std::unique_ptr<Request> request) {
Mutex::ScopedLock scoped_lock(block_lock_);
if (!main_thread_)
return false;
main_thread_->Post(std::move(request));
return true;
}
void MainThreadHandle::Reset() {
Mutex::ScopedLock scoped_lock(block_lock_);
main_thread_ = nullptr;
}
std::unique_ptr<InspectorSessionDelegate>
MainThreadHandle::MakeDelegateThreadSafe(
std::unique_ptr<InspectorSessionDelegate> delegate) {
int id = newObjectId();
main_thread_->AddObject(id, WrapInDeletable(std::move(delegate)));
return std::unique_ptr<InspectorSessionDelegate>(
new ThreadSafeDelegate(shared_from_this(), id));
}
bool MainThreadHandle::Expired() {
Mutex::ScopedLock scoped_lock(block_lock_);
return main_thread_ == nullptr;
}
} // namespace inspector
} // namespace node
|