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_SHELL_COMMON_ISOLATE_CONFIGURATION_H_ |
6 | #define FLUTTER_SHELL_COMMON_ISOLATE_CONFIGURATION_H_ |
7 | |
8 | #include <future> |
9 | #include <memory> |
10 | #include <string> |
11 | |
12 | #include "flutter/assets/asset_manager.h" |
13 | #include "flutter/assets/asset_resolver.h" |
14 | #include "flutter/common/settings.h" |
15 | #include "flutter/fml/macros.h" |
16 | #include "flutter/fml/mapping.h" |
17 | #include "flutter/fml/memory/weak_ptr.h" |
18 | #include "flutter/runtime/dart_isolate.h" |
19 | |
20 | namespace flutter { |
21 | |
22 | //------------------------------------------------------------------------------ |
23 | /// @brief An isolate configuration is a collection of snapshots and asset |
24 | /// managers that the engine will use to configure the isolate |
25 | /// before invoking its root entrypoint. The set of snapshots must |
26 | /// be sufficient for the engine to move the isolate from the |
27 | /// |DartIsolate::Phase::LibrariesSetup| phase to the |
28 | /// |DartIsolate::Phase::Ready| phase. Note that the isolate |
29 | /// configuration will not be collected till the isolate tied to the |
30 | /// configuration as well as any and all child isolates of that |
31 | /// isolate are collected. The engine may ask the configuration to |
32 | /// prepare multiple isolates. All subclasses of this class must be |
33 | /// thread safe as the configuration may be created, collected and |
34 | /// used on multiple threads. Usually these threads are engine or VM |
35 | /// managed so care must be taken to ensure that subclasses do not |
36 | /// reference any thread local state. |
37 | /// |
38 | class IsolateConfiguration { |
39 | public: |
40 | //---------------------------------------------------------------------------- |
41 | /// @brief Attempts to infer the isolate configuration from the |
42 | /// `Settings` object. If the VM is configured for AOT mode, |
43 | /// snapshot resolution is attempted with predefined symbols |
44 | /// present in the currently loaded process. In JIT mode, Dart |
45 | /// kernel file resolution is attempted in the assets directory. |
46 | /// If an IO worker is specified, snapshot resolution may be |
47 | /// attempted on the serial worker task runner. The worker task |
48 | /// runner thread must remain valid and running till after the |
49 | /// shell associated with the engine used to launch the isolate |
50 | /// for which this run configuration is used is collected. |
51 | /// |
52 | /// @param[in] settings The settings |
53 | /// @param[in] asset_manager The asset manager |
54 | /// @param[in] io_worker An optional IO worker. Specify `nullptr` is a |
55 | /// worker should not be used or one is not |
56 | /// available. |
57 | /// |
58 | /// @return An isolate configuration if one can be inferred from the |
59 | /// settings. If not, returns `nullptr`. |
60 | /// |
61 | static std::unique_ptr<IsolateConfiguration> InferFromSettings( |
62 | const Settings& settings, |
63 | std::shared_ptr<AssetManager> asset_manager, |
64 | fml::RefPtr<fml::TaskRunner> io_worker); |
65 | |
66 | //---------------------------------------------------------------------------- |
67 | /// @brief Creates an AOT isolate configuration using snapshot symbols |
68 | /// present in the currently loaded process. These symbols need to |
69 | /// be given to the Dart VM on bootstrap and hence have already |
70 | /// been resolved. |
71 | /// |
72 | /// @return An AOT isolate configuration. |
73 | /// |
74 | static std::unique_ptr<IsolateConfiguration> CreateForAppSnapshot(); |
75 | |
76 | //---------------------------------------------------------------------------- |
77 | /// @brief Creates a JIT isolate configuration using a list of futures to |
78 | /// snapshots defining the ready isolate state. In environments |
79 | /// where snapshot resolution is extremely expensive, embedders |
80 | /// attempt to resolve snapshots on worker thread(s) and return |
81 | /// the future of the promise of snapshot resolution to this |
82 | /// method. That way, snapshot resolution begins well before |
83 | /// isolate launch is attempted by the engine. |
84 | /// |
85 | /// @param[in] kernel_pieces The list of futures to Dart kernel snapshots. |
86 | /// |
87 | /// @return A JIT isolate configuration. |
88 | /// |
89 | static std::unique_ptr<IsolateConfiguration> CreateForKernelList( |
90 | std::vector<std::future<std::unique_ptr<const fml::Mapping>>> |
91 | kernel_pieces); |
92 | |
93 | //---------------------------------------------------------------------------- |
94 | /// @brief Creates a JIT isolate configuration using the specified |
95 | /// snapshot. This is a convenience method for the |
96 | /// `CreateForKernelList` method that takes a list of futures to |
97 | /// Dart kernel snapshots. |
98 | /// |
99 | /// @see CreateForKernelList() |
100 | /// |
101 | /// @param[in] kernel The kernel snapshot. |
102 | /// |
103 | /// @return A JIT isolate configuration. |
104 | /// |
105 | static std::unique_ptr<IsolateConfiguration> CreateForKernel( |
106 | std::unique_ptr<const fml::Mapping> kernel); |
107 | |
108 | //---------------------------------------------------------------------------- |
109 | /// @brief Creates a JIT isolate configuration using the specified |
110 | /// snapshots. This is a convenience method for the |
111 | /// `CreateForKernelList` method that takes a list of futures to |
112 | /// Dart kernel snapshots. |
113 | /// |
114 | /// @see CreateForKernelList() |
115 | /// |
116 | /// @param[in] kernel_pieces The kernel pieces |
117 | /// |
118 | /// @return { description_of_the_return_value } |
119 | /// |
120 | static std::unique_ptr<IsolateConfiguration> CreateForKernelList( |
121 | std::vector<std::unique_ptr<const fml::Mapping>> kernel_pieces); |
122 | |
123 | //---------------------------------------------------------------------------- |
124 | /// @brief Create an isolate configuration. This has no threading |
125 | /// restrictions. |
126 | /// |
127 | IsolateConfiguration(); |
128 | |
129 | //---------------------------------------------------------------------------- |
130 | /// @brief Destroys an isolate configuration. This has no threading |
131 | /// restrictions and may be collection of configurations may occur |
132 | /// on any thread (and usually happens on an internal VM managed |
133 | /// thread pool thread). |
134 | /// |
135 | virtual ~IsolateConfiguration(); |
136 | |
137 | //---------------------------------------------------------------------------- |
138 | /// @brief When an isolate is created and sufficiently initialized to |
139 | /// move it into the `DartIsolate::Phase::LibrariesSetup` phase, |
140 | /// this method is invoked on the isolate to then move the isolate |
141 | /// into the `DartIsolate::Phase::Ready` phase. Then isolate's |
142 | /// main entrypoint is then invoked to move it into the |
143 | /// `DartIsolate::Phase::Running` phase. This method will be |
144 | /// called each time the root isolate is launched (which may be |
145 | /// multiple times in cold-restart scenarios) as well as one each |
146 | /// for any child isolates referenced by that isolate. |
147 | /// |
148 | /// @param isolate The isolate which is already in the |
149 | /// `DartIsolate::Phase::LibrariesSetup` phase. |
150 | /// |
151 | /// @return Returns true if the isolate could be configured. Unless this |
152 | /// returns true, the engine will not move the isolate to the |
153 | /// `DartIsolate::Phase::Ready` phase for subsequent run. |
154 | /// |
155 | bool PrepareIsolate(DartIsolate& isolate); |
156 | |
157 | protected: |
158 | virtual bool DoPrepareIsolate(DartIsolate& isolate) = 0; |
159 | |
160 | private: |
161 | FML_DISALLOW_COPY_AND_ASSIGN(IsolateConfiguration); |
162 | }; |
163 | |
164 | } // namespace flutter |
165 | |
166 | #endif // FLUTTER_SHELL_COMMON_ISOLATE_CONFIGURATION_H_ |
167 | |