1 // Copyright 2022 The Android Open Source Project
2 //
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 expresso or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #pragma once
16 
17 namespace gfxstream {
18 namespace gl {
19 class TextureDraw;
20 }  // namespace gl
21 }  // namespace gfxstream
22 
23 namespace gfxstream {
24 
25 // ContextHelper interface class used during Buffer and ColorBuffer
26 // operations. This is introduced to remove coupling from the FrameBuffer
27 // class implementation.
28 class ContextHelper {
29   public:
30     ContextHelper() = default;
31     virtual ~ContextHelper() = default;
32     virtual bool setupContext() = 0;
33     virtual void teardownContext() = 0;
34     virtual bool isBound() const = 0;
35 };
36 
37 // Helper class to use a ContextHelper for some set of operations.
38 // Usage is pretty simple:
39 //
40 //     {
41 //        RecursiveScopedContextBind context(m_helper);
42 //        if (!context.isOk()) {
43 //            return false;   // something bad happened.
44 //        }
45 //        .... do something ....
46 //     }   // automatically calls m_helper->teardownContext();
47 //
48 class RecursiveScopedContextBind {
49   public:
RecursiveScopedContextBind(ContextHelper * helper)50     RecursiveScopedContextBind(ContextHelper* helper) : mHelper(helper) {
51         mIsBound = helper->setupContext();
52     }
53 
isOk()54     bool isOk() const { return mIsBound; }
55 
~RecursiveScopedContextBind()56     ~RecursiveScopedContextBind() { release(); }
57 
release()58     void release() {
59         if (mIsBound) {
60             mHelper->teardownContext();
61             mIsBound = false;
62         }
63     }
64 
65   private:
66     ContextHelper* mHelper;
67     bool mIsBound = false;
68 };
69 
70 }  // namespace gfxstream
71