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 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package sun.java2d.pipe;

import java.awt.AlphaComposite;

import java.awt.Color;

import java.awt.Composite;

import java.awt.Paint;

import java.awt.geom.AffineTransform;

import sun.java2d.pipe.hw.AccelSurface;

import sun.java2d.InvalidPipeException;

import sun.java2d.SunGraphics2D;

import sun.java2d.loops.XORComposite;

import static sun.java2d.pipe.BufferedOpCodes.*;

import static sun.java2d.pipe.BufferedRenderPipe.BYTES_PER_SPAN;

import java.lang.annotation.Native;

import java.lang.ref.Reference;

import java.lang.ref.WeakReference;

/**

 * Base context class for managing state in a single-threaded rendering

 * environment.  Each state-setting operation (e.g. SET_COLOR) is added to

 * the provided RenderQueue, which will be processed at a later time by a

 * single thread.  Note that the RenderQueue lock must be acquired before

 * calling the validate() method (or any other method in this class).  See

 * the RenderQueue class comments for a sample usage scenario.

 *

 * @see RenderQueue

 */

public abstract class BufferedContext {

    /*

     * The following flags help the internals of validate() determine

     * the appropriate (meaning correct, or optimal) code path when

     * setting up the current context.  The flags can be bitwise OR'd

     * together as needed.

     */

    /**

     * Indicates that no flags are needed; take all default code paths.

     */

    @Native public static final int NO_CONTEXT_FLAGS = (0 << 0);

    /**

     * Indicates that the source surface (or color value, if it is a simple

     * rendering operation) is opaque (has an alpha value of 1.0).  If this

     * flag is present, it allows us to disable blending in certain

     * situations in order to improve performance.

     */

    @Native public static final int SRC_IS_OPAQUE    = (1 << 0);

    /**

     * Indicates that the operation uses an alpha mask, which may determine

     * the code path that is used when setting up the current paint state.

     */

    @Native public static final int USE_MASK         = (1 << 1);

    protected RenderQueue rq;

    protected RenderBuffer buf;

    /**

     * This is a reference to the most recently validated BufferedContext.  If

     * this value is null, it means that there is no current context.  It is

     * provided here so that validate() only needs to do a quick reference

     * check to see if the BufferedContext passed to that method is the same

     * as the one we've cached here.

     */

    protected static BufferedContext currentContext;

    private Reference<AccelSurface> validSrcDataRef = new WeakReference<>(null);

    private Reference<AccelSurface> validDstDataRef = new WeakReference<>(null);

    private Reference<Region> validClipRef = new WeakReference<>(null);

    private Reference<Composite> validCompRef = new WeakReference<>(null);

    private Reference<Paint> validPaintRef = new WeakReference<>(null);

    // renamed from isValidatedPaintAColor as part of a work around for 6764257

    private boolean         isValidatedPaintJustAColor;

    private int             validatedRGB;

    private int             validatedFlags;

    private boolean         xformInUse;

    private AffineTransform transform;

    protected BufferedContext(RenderQueue rq) {

        this.rq = rq;

        this.buf = rq.getBuffer();

    }

    /**

     * Fetches the BufferedContextContext associated with the dst. surface

     * and validates the context using the given parameters.  Most rendering

     * operations will call this method first in order to set the necessary

     * state before issuing rendering commands.

     *

     * Note: must be called while the RenderQueue lock is held.

     *

     * It's assumed that the type of surfaces has been checked by the Renderer

     *

     * @throws InvalidPipeException if either src or dest surface is not valid

     * or lost

     * @see RenderQueue#lock

     * @see RenderQueue#unlock

     */

    public static void validateContext(AccelSurface srcData,

                                       AccelSurface dstData,

                                       Region clip, Composite comp,

                                       AffineTransform xform,

                                       Paint paint, SunGraphics2D sg2d,

                                       int flags)

    {

        // assert rq.lock.isHeldByCurrentThread();

        BufferedContext context = dstData.getContext();

        context.validate(srcData, dstData,

                         clip, comp, xform, paint, sg2d, flags);

    }

    /**

     * Fetches the BufferedContextassociated with the surface

     * and disables all context state settings.

     *

     * Note: must be called while the RenderQueue lock is held.

     *

     * It's assumed that the type of surfaces has been checked by the Renderer

     *

     * @throws InvalidPipeException if the surface is not valid

     * or lost

     * @see RenderQueue#lock

     * @see RenderQueue#unlock

     */

    public static void validateContext(AccelSurface surface) {

        // assert rt.lock.isHeldByCurrentThread();

        validateContext(surface, surface,

                        null, null, null, null, null, NO_CONTEXT_FLAGS);

    }

    /**

     * Validates the given parameters against the current state for this

     * context.  If this context is not current, it will be made current

     * for the given source and destination surfaces, and the viewport will

     * be updated.  Then each part of the context state (clip, composite,

     * etc.) is checked against the previous value.  If the value has changed

     * since the last call to validate(), it will be updated accordingly.

     *

     * Note that the SunGraphics2D parameter is only used for the purposes

     * of validating a (non-null) Paint parameter.  In all other cases it

     * is safe to pass a null SunGraphics2D and it will be ignored.

     *

     * Note: must be called while the RenderQueue lock is held.

     *

     * It's assumed that the type of surfaces has been checked by the Renderer

     *

     * @throws InvalidPipeException if either src or dest surface is not valid

     * or lost

     */

    public void validate(AccelSurface srcData, AccelSurface dstData,

                         Region clip, Composite comp,

                         AffineTransform xform,

                         Paint paint, SunGraphics2D sg2d, int flags)

    {

        // assert rq.lock.isHeldByCurrentThread();

        boolean updateClip = false;

        boolean updatePaint = false;

        if (!dstData.isValid() ||

            dstData.isSurfaceLost() || srcData.isSurfaceLost())

        {

            invalidateContext();

            throw new InvalidPipeException("bounds changed or surface lost");

        }

        if (paint instanceof Color) {

            // REMIND: not 30-bit friendly

            int newRGB = ((Color)paint).getRGB();

            if (isValidatedPaintJustAColor) {

                if (newRGB != validatedRGB) {

                    validatedRGB = newRGB;

                    updatePaint = true;

                }

            } else {

                validatedRGB = newRGB;

                updatePaint = true;

                isValidatedPaintJustAColor = true;

            }

        } else if (validPaintRef.get() != paint) {

            updatePaint = true;

            // this should be set when we are switching from paint to color

            // in which case this condition will be true

            isValidatedPaintJustAColor = false;

        }

        final AccelSurface validatedSrcData = validSrcDataRef.get();

        final AccelSurface validatedDstData = validDstDataRef.get();

        if ((currentContext != this) ||

            (srcData != validatedSrcData) ||

            (dstData != validatedDstData))

        {

            if (dstData != validatedDstData) {

                // the clip is dependent on the destination surface, so we

                // need to update it if we have a new destination surface

                updateClip = true;

            }

            if (paint == null) {

                // make sure we update the color state (otherwise, it might

                // not be updated if this is the first time the context

                // is being validated)

                updatePaint = true;

            }

            // update the current source and destination surfaces

            setSurfaces(srcData, dstData);

            currentContext = this;

            validSrcDataRef = new WeakReference<>(srcData);

            validDstDataRef = new WeakReference<>(dstData);

        }

        // validate clip

        final Region validatedClip = validClipRef.get();

        if ((clip != validatedClip) || updateClip) {

            if (clip != null) {

                if (updateClip ||

                    validatedClip == null ||

                    !(validatedClip.isRectangular() && clip.isRectangular()) ||

                    ((clip.getLoX() != validatedClip.getLoX() ||

                      clip.getLoY() != validatedClip.getLoY() ||

                      clip.getHiX() != validatedClip.getHiX() ||

                      clip.getHiY() != validatedClip.getHiY())))

                {

                    setClip(clip);

                }

            } else {

                resetClip();

            }

            validClipRef = new WeakReference<>(clip);

        }

        // validate composite (note that a change in the context flags

        // may require us to update the composite state, even if the

        // composite has not changed)

        if ((comp != validCompRef.get()) || (flags != validatedFlags)) {

            if (comp != null) {

                setComposite(comp, flags);

            } else {

                resetComposite();

            }

            // the paint state is dependent on the composite state, so make

            // sure we update the color below

            updatePaint = true;

            validCompRef = new WeakReference<>(comp);

            validatedFlags = flags;

        }

        // validate transform

        boolean txChanged = false;

        if (xform == null) {

            if (xformInUse) {

                resetTransform();

                xformInUse = false;

                txChanged = true;

            } else if (sg2d != null && !sg2d.transform.equals(transform)) {

                txChanged = true;

            }

            if (sg2d != null && txChanged) {

                transform = new AffineTransform(sg2d.transform);

            }

        } else {

            setTransform(xform);

            xformInUse = true;

            txChanged = true;

        }

        // non-Color paints may require paint revalidation

        if (!isValidatedPaintJustAColor && txChanged) {

            updatePaint = true;

        }

        // validate paint

        if (updatePaint) {

            if (paint != null) {

                BufferedPaints.setPaint(rq, sg2d, paint, flags);

            } else {

                BufferedPaints.resetPaint(rq);

            }

            validPaintRef = new WeakReference<>(paint);

        }

        // mark dstData dirty

        // REMIND: is this really needed now? we do it in SunGraphics2D..

        dstData.markDirty();

    }

    /**

     * Invalidates the surfaces associated with this context.  This is

     * useful when the context is no longer needed, and we want to break

     * the chain caused by these surface references.

     *

     * Note: must be called while the RenderQueue lock is held.

     *

     * @see RenderQueue#lock

     * @see RenderQueue#unlock

     */

    private void invalidateSurfaces() {

        validSrcDataRef.clear();

        validDstDataRef.clear();

    }

    private void setSurfaces(AccelSurface srcData,

                             AccelSurface dstData)

    {

        // assert rq.lock.isHeldByCurrentThread();

        rq.ensureCapacityAndAlignment(20, 4);

        buf.putInt(SET_SURFACES);

        buf.putLong(srcData.getNativeOps());

        buf.putLong(dstData.getNativeOps());

    }

    private void resetClip() {

        // assert rq.lock.isHeldByCurrentThread();

        rq.ensureCapacity(4);

        buf.putInt(RESET_CLIP);

    }

    private void setClip(Region clip) {

        // assert rq.lock.isHeldByCurrentThread();

        if (clip.isRectangular()) {

            rq.ensureCapacity(20);

            buf.putInt(SET_RECT_CLIP);

            buf.putInt(clip.getLoX()).putInt(clip.getLoY());

            buf.putInt(clip.getHiX()).putInt(clip.getHiY());

        } else {

            rq.ensureCapacity(28); // so that we have room for at least a span

            buf.putInt(BEGIN_SHAPE_CLIP);

            buf.putInt(SET_SHAPE_CLIP_SPANS);

            // include a placeholder for the span count

            int countIndex = buf.position();

            buf.putInt(0);

            int spanCount = 0;

            int remainingSpans = buf.remaining() / BYTES_PER_SPAN;

            SpanIterator si = clip.getSpanIterator();

            while (si.nextSpan(span)) {

                if (remainingSpans == 0) {

                    buf.putInt(countIndex, spanCount);

                    rq.flushNow();

                    buf.putInt(SET_SHAPE_CLIP_SPANS);

                    countIndex = buf.position();

                    buf.putInt(0);

                    spanCount = 0;

                    remainingSpans = buf.remaining() / BYTES_PER_SPAN;

                }

                buf.putInt(span[0]); // x1

                buf.putInt(span[1]); // y1

                buf.putInt(span[2]); // x2

                buf.putInt(span[3]); // y2

                spanCount++;

                remainingSpans--;

            }

            buf.putInt(countIndex, spanCount);

            rq.ensureCapacity(4);

            buf.putInt(END_SHAPE_CLIP);

        }

    }

    private void resetComposite() {

        // assert rq.lock.isHeldByCurrentThread();

        rq.ensureCapacity(4);

        buf.putInt(RESET_COMPOSITE);

    }

    private void setComposite(Composite comp, int flags) {

        // assert rq.lock.isHeldByCurrentThread();

        if (comp instanceof AlphaComposite) {

            AlphaComposite ac = (AlphaComposite)comp;

            rq.ensureCapacity(16);

            buf.putInt(SET_ALPHA_COMPOSITE);

            buf.putInt(ac.getRule());

            buf.putFloat(ac.getAlpha());

            buf.putInt(flags);

        } else if (comp instanceof XORComposite) {

            int xorPixel = ((XORComposite)comp).getXorPixel();

            rq.ensureCapacity(8);

            buf.putInt(SET_XOR_COMPOSITE);

            buf.putInt(xorPixel);

        } else {

            throw new InternalError("not yet implemented");

        }

    }

    private void resetTransform() {

        // assert rq.lock.isHeldByCurrentThread();

        rq.ensureCapacity(4);

        buf.putInt(RESET_TRANSFORM);

    }

    private void setTransform(AffineTransform xform) {

        // assert rq.lock.isHeldByCurrentThread();

        rq.ensureCapacityAndAlignment(52, 4);

        buf.putInt(SET_TRANSFORM);

        buf.putDouble(xform.getScaleX());

        buf.putDouble(xform.getShearY());

        buf.putDouble(xform.getShearX());

        buf.putDouble(xform.getScaleY());

        buf.putDouble(xform.getTranslateX());

        buf.putDouble(xform.getTranslateY());

    }

    /**

     * Resets this context's surfaces and all attributes.

     *

     * Note: must be called while the RenderQueue lock is held.

     *

     * @see RenderQueue#lock

     * @see RenderQueue#unlock

     */

    public void invalidateContext() {

        resetTransform();

        resetComposite();

        resetClip();

        BufferedPaints.resetPaint(rq);

        invalidateSurfaces();

        validCompRef.clear();

        validClipRef.clear();

        validPaintRef.clear();

        isValidatedPaintJustAColor = false;

        xformInUse = false;

    }

    /**

     * Returns a singleton {@code RenderQueue} object used by the rendering

     * pipeline.

     *

     * @return a render queue

     * @see RenderQueue

     */

    public abstract RenderQueue getRenderQueue();

    /**

     * Saves the state of this context.

     * It may reset the current context.

     *

     * Note: must be called while the RenderQueue lock is held.

     *

     * @see RenderQueue#lock

     * @see RenderQueue#unlock

     */

    public abstract void saveState();

    /**

     * Restores the native state of this context.

     * It may reset the current context.

     *

     * Note: must be called while the RenderQueue lock is held.

     *

     * @see RenderQueue#lock

     * @see RenderQueue#unlock

     */

    public abstract void restoreState();

}