1// Copyright 2013 The Flutter Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef FLUTTER_RUNTIME_DART_VM_LIFECYCLE_H_
6#define FLUTTER_RUNTIME_DART_VM_LIFECYCLE_H_
7
8#include <memory>
9
10#include "flutter/fml/macros.h"
11#include "flutter/lib/ui/isolate_name_server/isolate_name_server.h"
12#include "flutter/runtime/dart_vm.h"
13#include "flutter/runtime/service_protocol.h"
14#include "third_party/dart/runtime/include/dart_tools_api.h"
15
16namespace flutter {
17
18// A strong reference to the Dart VM. There can only be one VM running in the
19// process at any given time. A reference to the VM may only be obtained via the
20// |Create| method. In case there is already a running instance of the VM in the
21// process, a strong reference to that VM is obtained and the arguments to the
22// |Create| call ignored. If there is no VM already running in the process, a VM
23// is initialized in a thread safe manner and returned to the caller. The VM
24// will shutdown only when all callers relinquish their references (by
25// collecting their instances of this class).
26//
27// DartVMRef instances may be created on any thread.
28class DartVMRef {
29 public:
30 [[nodiscard]] static DartVMRef Create(
31 const Settings& settings,
32 fml::RefPtr<const DartSnapshot> vm_snapshot = nullptr,
33 fml::RefPtr<const DartSnapshot> isolate_snapshot = nullptr);
34
35 DartVMRef(const DartVMRef&) = default;
36
37 DartVMRef(DartVMRef&&);
38
39 ~DartVMRef();
40
41 // This is an inherently racy way to check if a VM instance is running and
42 // should not be used outside of unit-tests where there is a known threading
43 // model.
44 static bool IsInstanceRunning();
45
46 static std::shared_ptr<const DartVMData> GetVMData();
47
48 static std::shared_ptr<ServiceProtocol> GetServiceProtocol();
49
50 static std::shared_ptr<IsolateNameServer> GetIsolateNameServer();
51
52 explicit operator bool() const { return static_cast<bool>(vm_); }
53
54 DartVM* get() {
55 FML_DCHECK(vm_);
56 return vm_.get();
57 }
58
59 const DartVM* get() const {
60 FML_DCHECK(vm_);
61 return vm_.get();
62 }
63
64 DartVM* operator->() {
65 FML_DCHECK(vm_);
66 return vm_.get();
67 }
68
69 const DartVM* operator->() const {
70 FML_DCHECK(vm_);
71 return vm_.get();
72 }
73
74 DartVM* operator&() {
75 FML_DCHECK(vm_);
76 return vm_.get();
77 }
78
79 private:
80 friend class DartIsolate;
81
82 std::shared_ptr<DartVM> vm_;
83
84 explicit DartVMRef(std::shared_ptr<DartVM> vm);
85
86 // Only used by Dart Isolate to register itself with the VM.
87 static DartVM* GetRunningVM();
88};
89
90} // namespace flutter
91
92#endif // FLUTTER_RUNTIME_DART_VM_LIFECYCLE_H_
93

source code of flutter_engine/flutter/runtime/dart_vm_lifecycle.h