' Copyright (c) 2021 Huawei Device Co., Ltd.
' Licensed under the Apache License, Version 2.0 (the "License");
' you may not use this file except in compliance with the License.
' You may obtain a copy of the License at
'
' http://www.apache.org/licenses/LICENSE-2.0
'
' Unless required by applicable law or agreed to in writing, software
' distributed under the License is distributed on an "AS IS" BASIS,
' WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
' See the License for the specific language governing permissions and
' limitations under the License.

@startuml

skinparam monochrome true

title Mark phase
:Collect roots and mark them;

while (The Mark Stack is not empty)
    :Get an object from the stack;
    if (object is in collected space) then(Yes)
        if (The object is a Reference object in the same generation space with reference) then(Yes)
            if (the referent object is marked) then(Yes)
            else (No)
                :Put the object into the corresponding queue;
            endif
            :Mark all fields in Reference except 'referent';
        else (No)
            :Mark all fields in object;
        endif
    else (No)
    endif
endwhile
legend
    mark object == mark object and add all non-primitive fields to the Mark Stack
    mark all fields in object == mark all directly referenced objects and add their un-marked fields to Mark Stack
endlegend
stop
@enduml