File: api_event_handler.cc

package info (click to toggle)
chromium 139.0.7258.127-1
  • links: PTS, VCS
  • area: main
  • in suites:
  • size: 6,122,068 kB
  • sloc: cpp: 35,100,771; ansic: 7,163,530; javascript: 4,103,002; python: 1,436,920; asm: 946,517; xml: 746,709; pascal: 187,653; perl: 88,691; sh: 88,436; objc: 79,953; sql: 51,488; cs: 44,583; fortran: 24,137; makefile: 22,147; tcl: 15,277; php: 13,980; yacc: 8,984; ruby: 7,485; awk: 3,720; lisp: 3,096; lex: 1,327; ada: 727; jsp: 228; sed: 36
file content (439 lines) | stat: -rw-r--r-- 17,494 bytes parent folder | download | duplicates (3)
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
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "extensions/renderer/bindings/api_event_handler.h"

#include <algorithm>
#include <map>
#include <memory>
#include <utility>
#include <vector>

#include "base/check.h"
#include "base/containers/contains.h"
#include "base/functional/bind.h"
#include "base/functional/callback_helpers.h"
#include "base/memory/raw_ptr.h"
#include "base/notreached.h"
#include "base/supports_user_data.h"
#include "base/values.h"
#include "content/public/renderer/v8_value_converter.h"
#include "extensions/common/mojom/event_dispatcher.mojom.h"
#include "extensions/renderer/bindings/api_response_validator.h"
#include "extensions/renderer/bindings/event_emitter.h"
#include "extensions/renderer/bindings/get_per_context_data.h"
#include "extensions/renderer/bindings/js_runner.h"
#include "gin/converter.h"
#include "gin/data_object_builder.h"
#include "gin/handle.h"
#include "gin/per_context_data.h"

namespace extensions {

namespace {

constexpr char kFilterIdKey[] = "filterId";
constexpr char kEventNameKey[] = "eventName";

struct APIEventPerContextData : public base::SupportsUserData::Data {
  static constexpr char kPerContextDataKey[] = "extension_api_events";

  APIEventPerContextData(v8::Isolate* isolate) : isolate(isolate) {}
  ~APIEventPerContextData() override {
    DCHECK(emitters.empty())
        << "|emitters| should have been cleared by InvalidateContext()";
    DCHECK(massagers.empty())
        << "|massagers| should have been cleared by InvalidateContext()";
    DCHECK(anonymous_emitters.empty())
        << "|anonymous_emitters| should have been cleared by "
        << "InvalidateContext()";
  }

  // The associated v8::Isolate. Since this object is cleaned up at context
  // destruction, this should always be valid.
  raw_ptr<v8::Isolate> isolate;

  // A map from event name -> event emitter.
  std::map<std::string, v8::Global<v8::Object>> emitters;

  // A map from event name -> argument massager.
  std::map<std::string, v8::Global<v8::Function>> massagers;

  // The collection of anonymous events.
  std::vector<v8::Global<v8::Object>> anonymous_emitters;

  static APIEventPerContextData* GetFrom(v8::Local<v8::Context> context,
                                         CreatePerContextData should_create) {
    return GetPerContextData<APIEventPerContextData>(context, should_create,
                                                     context->GetIsolate());
  }
};

constexpr char APIEventPerContextData::kPerContextDataKey[];

void DispatchEvent(const v8::FunctionCallbackInfo<v8::Value>& info) {
  v8::Isolate* isolate = info.GetIsolate();
  v8::HandleScope handle_scope(isolate);
  if (info.Length() != 1 || !info[0]->IsArray()) {
    NOTREACHED();
  }

  v8::Local<v8::Context> context = isolate->GetCurrentContext();
  APIEventPerContextData* data =
      APIEventPerContextData::GetFrom(context, kDontCreateIfMissing);
  DCHECK(data);

  v8::Local<v8::Object> dispatch_data = info.Data().As<v8::Object>();
  v8::Local<v8::Value> filter_id_value =
      dispatch_data->Get(context, gin::StringToSymbol(isolate, kFilterIdKey))
          .ToLocalChecked();
  CHECK(filter_id_value->IsInt32());
  int filter_id = filter_id_value.As<v8::Int32>()->Value();

  v8::Local<v8::Value> event_name_value =
      dispatch_data->Get(context, gin::StringToSymbol(isolate, kEventNameKey))
          .ToLocalChecked();
  CHECK(event_name_value->IsString());
  v8::Local<v8::String> event_name_string = event_name_value.As<v8::String>();
  std::string event_name;
  gin::ConvertFromV8(isolate, event_name_string, &event_name);

  auto iter = data->emitters.find(event_name);
  if (iter == data->emitters.end()) {
    return;
  }
  v8::Global<v8::Object>& v8_emitter = iter->second;

  v8::LocalVector<v8::Value> args(isolate);
  CHECK(gin::Converter<v8::LocalVector<v8::Value>>::FromV8(isolate, info[0],
                                                           &args));

  EventEmitter* emitter = nullptr;
  gin::Converter<EventEmitter*>::FromV8(isolate, v8_emitter.Get(isolate),
                                        &emitter);
  CHECK(emitter);
  // Note: It's safe to use EventEmitter::FireSync() here because this should
  // only be triggered from a JS call, so we know JS is running.
  // TODO(devlin): It looks like the return result that requires this to be sync
  // is only used by the InputIME custom bindings; it would be kind of nice to
  // remove the dependency.
  mojom::EventFilteringInfoPtr filter = emitter->PopFilter(filter_id);
  info.GetReturnValue().Set(
      emitter->FireSync(context, &args, std::move(filter)));
}

}  // namespace

APIEventHandler::APIEventHandler(
    const APIEventListeners::ListenersUpdated& listeners_changed,
    const APIEventListeners::ContextOwnerIdGetter& context_owner_id_getter,
    ExceptionHandler* exception_handler)
    : listeners_changed_(listeners_changed),
      context_owner_id_getter_(context_owner_id_getter),
      exception_handler_(exception_handler) {}
APIEventHandler::~APIEventHandler() = default;

void APIEventHandler::SetResponseValidator(
    std::unique_ptr<APIResponseValidator> validator) {
  api_response_validator_ = std::move(validator);
}

v8::Local<v8::Object> APIEventHandler::CreateEventInstance(
    const std::string& event_name,
    bool supports_filters,
    bool supports_lazy_listeners,
    int max_listeners,
    bool notify_on_change,
    v8::Local<v8::Context> context) {
  // We need a context scope since gin::CreateHandle only takes the isolate
  // and infers the context from that.
  // TODO(devlin): This could be avoided if gin::CreateHandle could take a
  // context directly.
  v8::Context::Scope context_scope(context);

  APIEventPerContextData* data =
      APIEventPerContextData::GetFrom(context, kCreateIfMissing);
  DCHECK(data->emitters.find(event_name) == data->emitters.end());

  APIEventListeners::ListenersUpdated updated =
      notify_on_change ? listeners_changed_ : base::DoNothing();
  std::unique_ptr<APIEventListeners> listeners;
  if (supports_filters) {
    listeners = std::make_unique<FilteredEventListeners>(
        updated, event_name, context_owner_id_getter_, max_listeners,
        supports_lazy_listeners, &listener_tracker_);
  } else {
    listeners = std::make_unique<UnfilteredEventListeners>(
        updated, event_name, context_owner_id_getter_, max_listeners,
        supports_lazy_listeners, &listener_tracker_);
  }

  gin::Handle<EventEmitter> emitter_handle =
      gin::CreateHandle(context->GetIsolate(),
                        new EventEmitter(supports_filters, std::move(listeners),
                                         exception_handler_));
  CHECK(!emitter_handle.IsEmpty());
  v8::Local<v8::Value> emitter_value = emitter_handle.ToV8();
  CHECK(emitter_value->IsObject());
  v8::Local<v8::Object> emitter_object =
      v8::Local<v8::Object>::Cast(emitter_value);
  data->emitters[event_name] =
      v8::Global<v8::Object>(context->GetIsolate(), emitter_object);

  return emitter_object;
}

v8::Local<v8::Object> APIEventHandler::CreateAnonymousEventInstance(
    v8::Local<v8::Context> context) {
  v8::Context::Scope context_scope(context);
  APIEventPerContextData* data =
      APIEventPerContextData::GetFrom(context, kCreateIfMissing);
  bool supports_filters = false;

  // Anonymous events are not tracked, and thus don't need a name or a context
  // owner.
  std::string empty_event_name;
  ListenerTracker* anonymous_listener_tracker = nullptr;
  std::unique_ptr<APIEventListeners> listeners =
      std::make_unique<UnfilteredEventListeners>(
          base::DoNothing(), empty_event_name,
          APIEventListeners::ContextOwnerIdGetter(), binding::kNoListenerMax,
          false, anonymous_listener_tracker);
  gin::Handle<EventEmitter> emitter_handle =
      gin::CreateHandle(context->GetIsolate(),
                        new EventEmitter(supports_filters, std::move(listeners),
                                         exception_handler_));
  CHECK(!emitter_handle.IsEmpty());
  v8::Local<v8::Object> emitter_object = emitter_handle.ToV8().As<v8::Object>();
  data->anonymous_emitters.push_back(
      v8::Global<v8::Object>(context->GetIsolate(), emitter_object));
  return emitter_object;
}

void APIEventHandler::InvalidateCustomEvent(v8::Local<v8::Context> context,
                                            v8::Local<v8::Object> event) {
  EventEmitter* emitter = nullptr;
  APIEventPerContextData* data =
      APIEventPerContextData::GetFrom(context, kDontCreateIfMissing);
  // This could happen if a port (or JS) invalidates an event following
  // context destruction.
  // TODO(devlin): Is it better to fail gracefully here, or track all these
  // down for determinism?
  if (!data) {
    return;
  }

  if (!gin::Converter<EventEmitter*>::FromV8(context->GetIsolate(), event,
                                             &emitter)) {
    NOTREACHED();
  }

  emitter->Invalidate(context);
  // Can't just use `find(listeners_, listener)` here because `v8::Global<T>`
  // and `v8::Local<T>` do not have a common reference type and thus do not
  // satisfy `std::equality_comparable_with<>`. We could project using
  // `v8::Global<T>::Get()`, but that's less efficient.
  auto emitter_entry = std::ranges::find_if(
      data->anonymous_emitters,
      [&event](const auto& emitter) { return emitter == event; });
  if (emitter_entry == data->anonymous_emitters.end()) {
    NOTREACHED();
  }

  data->anonymous_emitters.erase(emitter_entry);
}

void APIEventHandler::FireEventInContext(const std::string& event_name,
                                         v8::Local<v8::Context> context,
                                         const base::Value::List& args,
                                         mojom::EventFilteringInfoPtr filter) {
  // Don't bother converting arguments if there are no listeners.
  // NOTE(devlin): This causes a double data and EventEmitter lookup, since
  // the v8 version below also checks for listeners. This should be very cheap,
  // but if we were really worried we could refactor.
  if (!HasListenerForEvent(event_name, context)) {
    return;
  }

  // Note: since we only convert the arguments once, if a listener modifies an
  // object (including an array), other listeners will see that modification.
  // TODO(devlin): This is how it's always been, but should it be?
  std::unique_ptr<content::V8ValueConverter> converter =
      content::V8ValueConverter::Create();

  v8::LocalVector<v8::Value> v8_args(context->GetIsolate());
  v8_args.reserve(args.size());
  for (const auto& arg : args) {
    v8_args.push_back(converter->ToV8Value(arg, context));
  }

  FireEventInContext(event_name, context, &v8_args, std::move(filter),
                     /*callback=*/v8::Local<v8::Function>());
}

void APIEventHandler::FireEventInContext(const std::string& event_name,
                                         v8::Local<v8::Context> context,
                                         v8::LocalVector<v8::Value>* arguments,
                                         mojom::EventFilteringInfoPtr filter,
                                         v8::Local<v8::Function> callback) {
  APIEventPerContextData* data =
      APIEventPerContextData::GetFrom(context, kDontCreateIfMissing);
  if (!data) {
    return;
  }

  auto iter = data->emitters.find(event_name);
  if (iter == data->emitters.end()) {
    return;
  }
  EventEmitter* emitter = nullptr;
  gin::Converter<EventEmitter*>::FromV8(
      context->GetIsolate(), iter->second.Get(context->GetIsolate()), &emitter);
  CHECK(emitter);

  auto massager_iter = data->massagers.find(event_name);
  if (massager_iter == data->massagers.end()) {
    // Validate the event arguments if there are no massagers (and validation is
    // enabled). Unfortunately, massagers both transform the event args from
    // unexpected -> expected and (badly!) from expected -> unexpected. As such,
    // we simply don't validate if there's a massager attached to the event.
    // TODO(crbug.com/40226845): Ideally, we'd be able to validate the response
    // after the massagers run. This requires fixing our schema for at least
    // chrome.permissions events.
    if (api_response_validator_) {
      api_response_validator_->ValidateEvent(context, event_name, *arguments);
    }

    emitter->Fire(context, arguments, std::move(filter), callback);
  } else {
    DCHECK(callback.IsEmpty())
        << "Can't use an event callback with argument massagers.";

    v8::Isolate* isolate = context->GetIsolate();
    v8::HandleScope handle_scope(isolate);
    v8::Local<v8::Function> massager = massager_iter->second.Get(isolate);

    v8::Local<v8::Array> args_array =
        v8::Array::New(isolate, arguments->size());
    {
      // Massagers expect an array of v8 values. Since this is a newly-
      // constructed array and we're assigning data properties, this shouldn't
      // be able to fail or be visible by other script.
      for (size_t i = 0; i < arguments->size(); ++i) {
        v8::Maybe<bool> success = args_array->CreateDataProperty(
            context, static_cast<uint32_t>(i), arguments->at(i));
        CHECK(success.ToChecked());
      }
    }

    // Curry in the native dispatch function. Some argument massagers take
    // extra liberties and call this asynchronously, so we can't just have the
    // massager return a modified array of arguments.
    // We don't store this in a template because the Data (event name) is
    // different for each instance. Luckily, this is called during dispatching
    // an event, rather than e.g. at initialization time.

    int filter_id = emitter->PushFilter(std::move(filter));

    v8::Local<v8::Object> dispatch_data =
        gin::DataObjectBuilder(isolate)
            .Set(kFilterIdKey, gin::ConvertToV8(isolate, filter_id))
            .Set(kEventNameKey, gin::ConvertToV8(isolate, event_name))
            .Build();

    v8::Local<v8::Function> dispatch_event =
        v8::Function::New(context, &DispatchEvent, std::move(dispatch_data))
            .ToLocalChecked();

    v8::Local<v8::Value> massager_args[] = {args_array, dispatch_event};
    JSRunner::Get(context)->RunJSFunction(massager, context, massager_args);
  }
}

void APIEventHandler::RegisterArgumentMassager(
    v8::Local<v8::Context> context,
    const std::string& event_name,
    v8::Local<v8::Function> massager) {
  APIEventPerContextData* data =
      APIEventPerContextData::GetFrom(context, kCreateIfMissing);
  DCHECK(!base::Contains(data->massagers, event_name));
  data->massagers[event_name].Reset(context->GetIsolate(), massager);
}

bool APIEventHandler::HasListenerForEvent(const std::string& event_name,
                                          v8::Local<v8::Context> context) {
  APIEventPerContextData* data =
      APIEventPerContextData::GetFrom(context, kDontCreateIfMissing);
  if (!data) {
    return false;
  }

  auto iter = data->emitters.find(event_name);
  if (iter == data->emitters.end()) {
    return false;
  }
  EventEmitter* emitter = nullptr;
  gin::Converter<EventEmitter*>::FromV8(
      context->GetIsolate(), iter->second.Get(context->GetIsolate()), &emitter);
  CHECK(emitter);
  return emitter->GetNumListeners() > 0;
}

void APIEventHandler::InvalidateContext(v8::Local<v8::Context> context) {
  DCHECK(gin::PerContextData::From(context))
      << "Trying to invalidate an already-invalid context.";
  APIEventPerContextData* data =
      APIEventPerContextData::GetFrom(context, kDontCreateIfMissing);
  if (!data) {
    return;
  }

  v8::Isolate* isolate = context->GetIsolate();
  v8::HandleScope scope(isolate);

  // This loop *shouldn't* allow any self-modification (i.e., no listeners
  // should be added or removed as a result of the iteration). If that changes,
  // we'll need to cache the listeners elsewhere before iterating.
  for (const auto& pair : data->emitters) {
    EventEmitter* emitter = nullptr;
    gin::Converter<EventEmitter*>::FromV8(isolate, pair.second.Get(isolate),
                                          &emitter);
    CHECK(emitter);
    emitter->Invalidate(context);
  }
  for (const auto& global : data->anonymous_emitters) {
    EventEmitter* emitter = nullptr;
    gin::Converter<EventEmitter*>::FromV8(isolate, global.Get(isolate),
                                          &emitter);
    CHECK(emitter);
    emitter->Invalidate(context);
  }

  data->emitters.clear();
  data->massagers.clear();
  data->anonymous_emitters.clear();

  // InvalidateContext() is called shortly (and, theoretically, synchronously)
  // before the PerContextData is deleted. We have a check that guarantees that
  // no new EventEmitters are created after the PerContextData is deleted, so
  // no new emitters should be created after this point.
}

size_t APIEventHandler::GetNumEventListenersForTesting(
    const std::string& event_name,
    v8::Local<v8::Context> context) {
  APIEventPerContextData* data =
      APIEventPerContextData::GetFrom(context, kDontCreateIfMissing);
  DCHECK(data);

  auto iter = data->emitters.find(event_name);
  CHECK(iter != data->emitters.end());
  EventEmitter* emitter = nullptr;
  gin::Converter<EventEmitter*>::FromV8(
      context->GetIsolate(), iter->second.Get(context->GetIsolate()), &emitter);
  CHECK(emitter);
  return emitter->GetNumListeners();
}

}  // namespace extensions