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1 /*
2  * Copyright (C) 2024 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef NODEJSTASKQUEUE_H
17 #define NODEJSTASKQUEUE_H
18 #include <meta/interface/intf_task_queue.h>
19 
20 #include "napi_api.h"
21 
22 /*
23  * NodeJSTaskQueue identifier
24  */
25 static constexpr BASE_NS::Uid JS_THREAD_DEP { "b2e8cef3-453a-4651-b564-5190f8b5190d" };
26 
27 /*
28  * NodeJSTaskQueue executes it's tasks in the thread where it was first initialized, which MUST have a valid napi_env.
29  * napi_env must be passed to the instance in a "Create" parameter block, in a parameter "env" of type "uintptr_t"
30  *
31  * See INodeJSTaskQueue for more information.
32  */
33 META_REGISTER_CLASS(NodeJSTaskQueue, "66aabbba-ec01-47f8-ac68-2393cfc76a9a", META_NS::ObjectCategoryBits::NO_CATEGORY)
34 
35 /*
36  * INodeJSTaskQueue can be used by tasks in NodeJSTaskQueue to access the napi_env where the tasks run.
37  *
38  *   "GetNapiEnv" result is only valid in the thread where it was created.
39  *   "Acquire" MUST be called on the creating thread.
40  *   "Release" MUST be called on the creating thread.
41  *
42  * Before the task queue can schedule/run tasks, the queue must be "acquired".
43  *
44  * Acquire must be called atleast once in the creating thread.
45  * Release must be called as many times as Acquire is done.
46  *
47  * after first acquired, the NodeJS message loop will be kept alive.
48  * after fully released, then AFTER all tasks in queue have run to completion, the javascript side resources are
49  * released, allowing NodeJS to terminate.
50  *
51  * while being fully released, the addtask methods will fail.
52  * requiring a new acquire to work again.
53  *
54  * NodeJSQueue is created and acquired by the SceneJS and released by SceneJS.
55  */
56 class INodeJSTaskQueue : public CORE_NS::IInterface {
57     META_INTERFACE(CORE_NS::IInterface, INodeJSTaskQueue, "9d898eee-f592-410b-bf72-c8baeaa65614");
58 
59 public:
60     // provides access to the environment.
61     // this is provided so tasks can do napi calls.
62     // ONLY safe to use while executing tasks INodeJSTaskQueue (or the thread where napi_env is created)
63     virtual napi_env GetNapiEnv() const = 0;
64 
65     // These are safe in the napi_env / js thread.
66 
67     // The following are counted.
68     // When released to 0, the queue will run to termination, and release JS resources
69     // Acquire can be used to allocate the said resources again.
70 
71     // Acquire makes sure that the queue can work
72     virtual bool Acquire() = 0;
73     // Release allows the resources to be released
74     virtual bool Release() = 0;
75 
76     // Returns if it's safe to destroy the instance. (fully released with no tasks)
77     virtual bool IsReleased() = 0;
78 };
79 
80 // creates and registers the main nodetaskqueue instance if it doesn't exist yet. (uses provided napi_env)
81 // MUST BE CALLED IN THE THREAD OWNING THE NAPI_ENV!
82 META_NS::ITaskQueue::Ptr GetOrCreateNodeTaskQueue(napi_env e);
83 
84 // unregisters the main nodetaskqueue instance.
85 // this SHOULD be called after no users left.
86 // and the queue being fully "Released".
87 // MUST BE CALLED IN THE THREAD OWNING THE NAPI_ENV!
88 bool DeinitNodeTaskQueue();
89 #endif
90