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
|
// Copyright 2010 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/extensions/gc-extension.h"
#include "include/v8-isolate.h"
#include "include/v8-microtask-queue.h"
#include "include/v8-object.h"
#include "include/v8-persistent-handle.h"
#include "include/v8-primitive.h"
#include "include/v8-template.h"
#include "src/base/optional.h"
#include "src/base/platform/platform.h"
#include "src/execution/isolate.h"
#include "src/heap/heap.h"
#include "src/tasks/cancelable-task.h"
namespace v8 {
namespace internal {
namespace {
enum class ExecutionType { kAsync, kSync };
struct GCOptions {
v8::Isolate::GarbageCollectionType type;
ExecutionType execution;
};
Maybe<bool> IsProperty(v8::Isolate* isolate, v8::Local<v8::Context> ctx,
v8::Local<v8::Object> object, const char* key,
const char* value) {
auto k = v8::String::NewFromUtf8(isolate, key).ToLocalChecked();
// Get will return undefined for non-existing keys which will make
// StrictEquals fail.
auto maybe_property = object->Get(ctx, k);
if (maybe_property.IsEmpty()) return Nothing<bool>();
return Just<bool>(maybe_property.ToLocalChecked()->StrictEquals(
v8::String::NewFromUtf8(isolate, value).ToLocalChecked()));
}
Maybe<GCOptions> Parse(v8::Isolate* isolate,
const v8::FunctionCallbackInfo<v8::Value>& args) {
// Default values.
auto options =
GCOptions{v8::Isolate::GarbageCollectionType::kFullGarbageCollection,
ExecutionType::kSync};
bool found_options_object = false;
if (args.Length() > 0 && args[0]->IsObject()) {
v8::HandleScope scope(isolate);
auto ctx = isolate->GetCurrentContext();
auto param = v8::Local<v8::Object>::Cast(args[0]);
auto maybe_type = IsProperty(isolate, ctx, param, "type", "minor");
if (maybe_type.IsNothing()) return Nothing<GCOptions>();
if (maybe_type.ToChecked()) {
found_options_object = true;
options.type =
v8::Isolate::GarbageCollectionType::kMinorGarbageCollection;
}
auto maybe_execution =
IsProperty(isolate, ctx, param, "execution", "async");
if (maybe_execution.IsNothing()) return Nothing<GCOptions>();
if (maybe_execution.ToChecked()) {
found_options_object = true;
options.execution = ExecutionType::kAsync;
}
}
// If no options object is present default to legacy behavior.
if (!found_options_object) {
options.type =
args[0]->BooleanValue(isolate)
? v8::Isolate::GarbageCollectionType::kMinorGarbageCollection
: v8::Isolate::GarbageCollectionType::kFullGarbageCollection;
}
return Just<GCOptions>(options);
}
void InvokeGC(v8::Isolate* isolate, ExecutionType execution_type,
v8::Isolate::GarbageCollectionType type) {
Heap* heap = reinterpret_cast<Isolate*>(isolate)->heap();
switch (type) {
case v8::Isolate::GarbageCollectionType::kMinorGarbageCollection:
heap->CollectGarbage(i::NEW_SPACE, i::GarbageCollectionReason::kTesting,
kGCCallbackFlagForced);
break;
case v8::Isolate::GarbageCollectionType::kFullGarbageCollection:
EmbedderStackStateScope stack_scope(
heap,
execution_type == ExecutionType::kAsync
? EmbedderStackStateScope::kImplicitThroughTask
: EmbedderStackStateScope::kExplicitInvocation,
execution_type == ExecutionType::kAsync
? StackState::kNoHeapPointers
: StackState::kMayContainHeapPointers);
heap->PreciseCollectAllGarbage(i::Heap::kNoGCFlags,
i::GarbageCollectionReason::kTesting,
kGCCallbackFlagForced);
break;
}
}
class AsyncGC final : public CancelableTask {
public:
~AsyncGC() final = default;
AsyncGC(v8::Isolate* isolate, v8::Local<v8::Promise::Resolver> resolver,
v8::Isolate::GarbageCollectionType type)
: CancelableTask(reinterpret_cast<Isolate*>(isolate)),
isolate_(isolate),
ctx_(isolate, isolate->GetCurrentContext()),
resolver_(isolate, resolver),
type_(type) {}
AsyncGC(const AsyncGC&) = delete;
AsyncGC& operator=(const AsyncGC&) = delete;
void RunInternal() final {
v8::HandleScope scope(isolate_);
InvokeGC(isolate_, ExecutionType::kAsync, type_);
auto resolver = v8::Local<v8::Promise::Resolver>::New(isolate_, resolver_);
auto ctx = Local<v8::Context>::New(isolate_, ctx_);
v8::MicrotasksScope microtasks_scope(
ctx, v8::MicrotasksScope::kDoNotRunMicrotasks);
resolver->Resolve(ctx, v8::Undefined(isolate_)).ToChecked();
}
private:
v8::Isolate* isolate_;
v8::Persistent<v8::Context> ctx_;
v8::Persistent<v8::Promise::Resolver> resolver_;
v8::Isolate::GarbageCollectionType type_;
};
} // namespace
v8::Local<v8::FunctionTemplate> GCExtension::GetNativeFunctionTemplate(
v8::Isolate* isolate, v8::Local<v8::String> str) {
return v8::FunctionTemplate::New(isolate, GCExtension::GC);
}
void GCExtension::GC(const v8::FunctionCallbackInfo<v8::Value>& args) {
v8::Isolate* isolate = args.GetIsolate();
// Immediate bailout if no arguments are provided.
if (args.Length() == 0) {
InvokeGC(isolate, ExecutionType::kSync,
v8::Isolate::GarbageCollectionType::kFullGarbageCollection);
return;
}
auto maybe_options = Parse(isolate, args);
if (maybe_options.IsNothing()) return;
GCOptions options = maybe_options.ToChecked();
switch (options.execution) {
case ExecutionType::kSync:
InvokeGC(isolate, ExecutionType::kSync, options.type);
break;
case ExecutionType::kAsync: {
v8::HandleScope scope(isolate);
auto resolver = v8::Promise::Resolver::New(isolate->GetCurrentContext())
.ToLocalChecked();
args.GetReturnValue().Set(resolver->GetPromise());
auto task_runner =
V8::GetCurrentPlatform()->GetForegroundTaskRunner(isolate);
CHECK(task_runner->NonNestableTasksEnabled());
task_runner->PostNonNestableTask(
std::make_unique<AsyncGC>(isolate, resolver, options.type));
} break;
}
}
} // namespace internal
} // namespace v8
|
