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Viewing changes to src/modules/Unity/Application/session.cpp

  • Committer: CI Train Bot
  • Author(s): Daniel d'Andrada
  • Date: 2016-05-11 09:08:25 UTC
  • mfrom: (484.1.2 promptBeforeSurfaceDraws)
  • Revision ID: ci-train-bot@canonical.com-20160511090825-fazlyfjv76mzsj0r
Session: Add a blank surface to the public list if it already has child prompt surfaces

A prompt session may come in too early, before its parent session got a chance
to draw its surface's first frame.

Normally that wouldn't be a problem and we could withhold that parent surface until
it's finally drawn to. But unfortunately the application process might be blocked,
unable to draw anything, until its child prompt session gets dismissed.

Because of that we have no option but to expose this blank surface to shell so that
it can display it along with the prompt surface on top of it, so that the user can
interact with it right away and finally unblock the application. Fixes: #1578665
Approved by: Unity8 CI Bot

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Lines of Context:
src/modules/Unity/Application/session.cpp
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    if (newSurface->isFirstFrameDrawn()) {
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        prependSurface(newSurface);
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    } else {
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        connect(newSurface, &MirSurfaceInterface::firstFrameDrawn,
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                this, [this, newSurface]() { this->prependSurface(newSurface); });
 
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        m_blankSurfaces.append(newSurface);
 
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        connect(newSurface, &QObject::destroyed, this, [this, newSurface]()
 
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            {
 
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                this->m_blankSurfaces.removeAll(newSurface);
 
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            });
 
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        connect(newSurface, &MirSurfaceInterface::firstFrameDrawn, this, [this, newSurface]()
 
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            {
 
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                this->m_blankSurfaces.removeAll(newSurface);
 
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                newSurface->disconnect(this);
 
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                this->prependSurface(newSurface);
 
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            });
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    }
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}
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        // we assume that the top-most surface is the one that caused the prompt session to show up.
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        auto promptSurfaceList = static_cast<MirSurfaceListModel*>(m_surfaceList.get(0)->promptSurfaceList());
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        promptSurfaceList->addSurfaceList(session->surfaceList());
 
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    } else if (m_blankSurfaces.count() > 0) {
 
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        // Prompt session came in too early.
 
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        // Parent session might be blocked until the prompt session is dismissed.
 
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        // So we cannot wait anymore and must put that blank surface on the surface list so that the
 
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        // user can see the prompt surface on top of that it and interact.
 
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        auto blankSurface = m_blankSurfaces.takeFirst();
 
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        auto promptSurfaceList = static_cast<MirSurfaceListModel*>(blankSurface->promptSurfaceList());
 
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        promptSurfaceList->addSurfaceList(session->surfaceList());
 
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        blankSurface->disconnect(this);
 
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        prependSurface(blankSurface);
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    }
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}
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