bridge/src/com/android/layoutlib/bridge/BridgeRenderSession.java

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * 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.
 */

package com.android.layoutlib.bridge;

import com.android.ide.common.rendering.api.LayoutLog;
import com.android.ide.common.rendering.api.RenderParams;
import com.android.ide.common.rendering.api.RenderSession;
import com.android.ide.common.rendering.api.ResourceReference;
import com.android.ide.common.rendering.api.ResourceValue;
import com.android.ide.common.rendering.api.Result;
import com.android.ide.common.rendering.api.ViewInfo;
import com.android.layoutlib.bridge.impl.RenderSessionImpl;
import com.android.tools.layoutlib.java.System_Delegate;

import android.annotation.NonNull;
import android.annotation.Nullable;
import android.os.Handler_Delegate;
import android.view.Choreographer;
import android.view.MotionEvent;

import java.awt.image.BufferedImage;
import java.util.Collections;
import java.util.List;
import java.util.Map;

/**
 * An implementation of {@link RenderSession}.
 *
 * This is a pretty basic class that does almost nothing. All of the work is done in
 * {@link RenderSessionImpl}.
 *
 */
public class BridgeRenderSession extends RenderSession {

    @Nullable
    private final RenderSessionImpl mSession;
    @NonNull
    private Result mLastResult;

    @Override
    public Result getResult() {
        return mLastResult;
    }

    @Override
    public BufferedImage getImage() {
        return mSession != null ? mSession.getImage() :
                new BufferedImage(1, 1, BufferedImage.TYPE_INT_ARGB);
    }

    @Override
    public List<ViewInfo> getRootViews() {
        return mSession != null ? mSession.getViewInfos() : Collections.emptyList();
    }

    @Override
    public List<ViewInfo> getSystemRootViews() {
        return mSession != null ? mSession.getSystemViewInfos() : Collections.emptyList();
    }

    @Override
    public Map<Object, Map<ResourceReference, ResourceValue>> getDefaultNamespacedProperties() {
        return mSession != null ? mSession.getDefaultNamespacedProperties() :
                Collections.emptyMap();
    }

    @Override
    public Map<Object, String> getDefaultStyles() {
        return mSession != null ? mSession.getDefaultStyles() : Collections.emptyMap();
    }

    @Override
    public Map<Object, ResourceReference> getDefaultNamespacedStyles() {
        return mSession != null ? mSession.getDefaultNamespacedStyles() : Collections.emptyMap();
    }

    @Override
    public Result measure(long timeout) {
        if (mSession != null) {
            try {
                Bridge.prepareThread();
                mLastResult = mSession.acquire(timeout);
                if (mLastResult.isSuccess()) {
                    mSession.invalidateRenderingSize();
                    mLastResult = mSession.measure();
                }
            } finally {
                mSession.release();
                Bridge.cleanupThread();
            }
        }

        return mLastResult;
    }

    @Override
    public Result render(long timeout, boolean forceMeasure) {
        if (mSession != null) {
            try {
                Bridge.prepareThread();
                mLastResult = mSession.acquire(timeout);
                if (mLastResult.isSuccess()) {
                    if (forceMeasure) {
                        mSession.invalidateRenderingSize();
                    }
                    mLastResult = mSession.render(false /*freshRender*/);
                }
            } finally {
                mSession.release();
                Bridge.cleanupThread();
            }
        }

        return mLastResult;
    }

    @Override
    public void setSystemTimeNanos(long nanos) {
        System_Delegate.setNanosTime(nanos);
    }

    @Override
    public void setSystemBootTimeNanos(long nanos) {
        System_Delegate.setBootTimeNanos(nanos);
    }

    @Override
    public void setElapsedFrameTimeNanos(long nanos) {
        if (mSession != null) {
            mSession.setElapsedFrameTimeNanos(nanos);
        }
    }

    @Override
    public boolean executeCallbacks(long nanos) {
        // Currently, Compose relies on Choreographer frame callback and Handler#postAtFrontOfQueue.
        // Calls to Handler are handled by Handler_Delegate and can be executed by Handler_Delegate#
        // executeCallbacks. Choreographer frame callback is handled by Choreographer#doFrame.
        //
        // If we want to animate platform widgets as well we will also have to execute callbacks
        // passed to the Handler (Handler_Delegate in our case) with sendMessageAtTime. For this
        // purpose, we will have to save those messages with uptimes and execute appropriate (if
        // uptime has passed) callbacks here.
        try {
            Bridge.prepareThread();
            boolean hasMoreCallbacks = Handler_Delegate.executeCallbacks();
            Choreographer.getInstance().doFrame(nanos, 0);
            return hasMoreCallbacks;
        } catch (Throwable t) {
            Bridge.getLog().error(LayoutLog.TAG_BROKEN, "Failed executing Choreographer#doFrame "
                    , t, null, null);
            return false;
        } finally {
            Bridge.cleanupThread();
        }
    }

    private static int toMotionEventType(TouchEventType eventType) {
        switch (eventType) {
            case PRESS:
                return MotionEvent.ACTION_DOWN;
            case RELEASE:
                return MotionEvent.ACTION_UP;
            case DRAG:
                return MotionEvent.ACTION_MOVE;
        }
        throw new IllegalStateException("Unexpected touch event type: " + eventType);
    }

    @Override
    public void triggerTouchEvent(TouchEventType type, int x, int y) {
        int motionEventType = toMotionEventType(type);
        if (mSession != null) {
            try {
                Bridge.prepareThread();
                mLastResult = mSession.acquire(RenderParams.DEFAULT_TIMEOUT);
                mSession.dispatchTouchEvent(motionEventType, System_Delegate.nanoTime(), x, y);
            } finally {
                mSession.release();
                Bridge.cleanupThread();
            }
        }
    }

    @Override
    public void dispose() {
        if (mSession != null) {
            mSession.dispose();
        }
    }

    /*package*/ BridgeRenderSession(@Nullable RenderSessionImpl scene, @NonNull Result lastResult) {
        mSession = scene;
        if (scene != null) {
            mSession.setScene(this);
        }
        mLastResult = lastResult;
    }
}