/*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "SkLiteDL.h"
#include <algorithm>
#include "SkCanvas.h"
#include "SkCanvasPriv.h"
#include "SkData.h"
#include "SkDrawShadowInfo.h"
#include "SkImage.h"
#include "SkImageFilter.h"
#include "SkMath.h"
#include "SkPicture.h"
#include "SkRSXform.h"
#include "SkRegion.h"
#include "SkTextBlob.h"
#include "SkVertices.h"

#ifndef SKLITEDL_PAGE
    #define SKLITEDL_PAGE 4096
#endif

// A stand-in for an optional SkRect which was not set, e.g. bounds for a saveLayer().
static const SkRect kUnset = { SK_ScalarInfinity, 0,0,0};
static const SkRect* maybe_unset(const SkRect& r) {
    return r.left() == SK_ScalarInfinity ? nullptr : &r;
}

// copy_v(dst, src,n, src,n, ...) copies an arbitrary number of typed srcs into dst.
static void copy_v(void* dst) {}

template <typename S, typename... Rest>
static void copy_v(void* dst, const S* src, int n, Rest&&... rest) {
    SkASSERTF(((uintptr_t)dst & (alignof(S)-1)) == 0,
              "Expected %p to be aligned for at least %zu bytes.", dst, alignof(S));
    sk_careful_memcpy(dst, src, n*sizeof(S));
    copy_v(SkTAddOffset<void>(dst, n*sizeof(S)), std::forward<Rest>(rest)...);
}

// Helper for getting back at arrays which have been copy_v'd together after an Op.
template <typename D, typename T>
static const D* pod(const T* op, size_t offset = 0) {
    return SkTAddOffset<const D>(op+1, offset);
}

namespace {
#define TYPES(M)                                                                       \
    M(Flush) M(Save) M(Restore) M(SaveLayer) M(SaveBehind)                             \
    M(Concat) M(SetMatrix) M(Translate)                                                \
    M(ClipPath) M(ClipRect) M(ClipRRect) M(ClipRegion)                                 \
    M(DrawPaint) M(DrawPath) M(DrawRect) M(DrawEdgeAARect)                             \
    M(DrawRegion) M(DrawOval) M(DrawArc)                                               \
    M(DrawRRect) M(DrawDRRect) M(DrawAnnotation) M(DrawDrawable) M(DrawPicture)        \
    M(DrawImage) M(DrawImageNine) M(DrawImageRect) M(DrawImageLattice) M(DrawImageSet) \
    M(DrawTextBlob)                                                                    \
    M(DrawPatch) M(DrawPoints) M(DrawVertices) M(DrawAtlas) M(DrawShadowRec)

#define M(T) T,
    enum class Type : uint8_t { TYPES(M) };
#undef M

    struct Op {
        uint32_t type :  8;
        uint32_t skip : 24;
    };
    static_assert(sizeof(Op) == 4, "");

    struct Flush final : Op {
        static const auto kType = Type::Flush;
        void draw(SkCanvas* c, const SkMatrix&) const { c->flush(); }
    };

    struct Save final : Op {
        static const auto kType = Type::Save;
        void draw(SkCanvas* c, const SkMatrix&) const { c->save(); }
    };
    struct Restore final : Op {
        static const auto kType = Type::Restore;
        void draw(SkCanvas* c, const SkMatrix&) const { c->restore(); }
    };
    struct SaveLayer final : Op {
        static const auto kType = Type::SaveLayer;
        SaveLayer(const SkRect* bounds, const SkPaint* paint,
                  const SkImageFilter* backdrop, const SkImage* clipMask,
                  const SkMatrix* clipMatrix, SkCanvas::SaveLayerFlags flags) {
            if (bounds) { this->bounds = *bounds; }
            if (paint)  { this->paint  = *paint;  }
            this->backdrop = sk_ref_sp(backdrop);
            this->clipMask = sk_ref_sp(clipMask);
            this->clipMatrix = clipMatrix ? *clipMatrix : SkMatrix::I();
            this->flags = flags;
        }
        SkRect                     bounds = kUnset;
        SkPaint                    paint;
        sk_sp<const SkImageFilter> backdrop;
        sk_sp<const SkImage>       clipMask;
        SkMatrix                   clipMatrix;
        SkCanvas::SaveLayerFlags   flags;
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->saveLayer({ maybe_unset(bounds), &paint, backdrop.get(), clipMask.get(),
                           clipMatrix.isIdentity() ? nullptr : &clipMatrix, flags });
        }
    };
    struct SaveBehind final : Op {
        static const auto kType = Type::SaveBehind;
        SaveBehind(const SkRect* subset) {
            if (subset) { this->subset = *subset; }
        }
        SkRect  subset = kUnset;
        void draw(SkCanvas* c, const SkMatrix&) const {
            SkCanvasPriv::SaveBehind(c, maybe_unset(subset));
        }
    };
    struct Concat final : Op {
        static const auto kType = Type::Concat;
        Concat(const SkMatrix& matrix) : matrix(matrix) {}
        SkMatrix matrix;
        void draw(SkCanvas* c, const SkMatrix&) const { c->concat(matrix); }
    };
    struct SetMatrix final : Op {
        static const auto kType = Type::SetMatrix;
        SetMatrix(const SkMatrix& matrix) : matrix(matrix) {}
        SkMatrix matrix;
        void draw(SkCanvas* c, const SkMatrix& original) const {
            c->setMatrix(SkMatrix::Concat(original, matrix));
        }
    };
    struct Translate final : Op {
        static const auto kType = Type::Translate;
        Translate(SkScalar dx, SkScalar dy) : dx(dx), dy(dy) {}
        SkScalar dx,dy;
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->translate(dx, dy);
        }
    };

    struct ClipPath final : Op {
        static const auto kType = Type::ClipPath;
        ClipPath(const SkPath& path, SkClipOp op, bool aa) : path(path), op(op), aa(aa) {}
        SkPath   path;
        SkClipOp op;
        bool     aa;
        void draw(SkCanvas* c, const SkMatrix&) const { c->clipPath(path, op, aa); }
    };
    struct ClipRect final : Op {
        static const auto kType = Type::ClipRect;
        ClipRect(const SkRect& rect, SkClipOp op, bool aa) : rect(rect), op(op), aa(aa) {}
        SkRect   rect;
        SkClipOp op;
        bool     aa;
        void draw(SkCanvas* c, const SkMatrix&) const { c->clipRect(rect, op, aa); }
    };
    struct ClipRRect final : Op {
        static const auto kType = Type::ClipRRect;
        ClipRRect(const SkRRect& rrect, SkClipOp op, bool aa) : rrect(rrect), op(op), aa(aa) {}
        SkRRect  rrect;
        SkClipOp op;
        bool     aa;
        void draw(SkCanvas* c, const SkMatrix&) const { c->clipRRect(rrect, op, aa); }
    };
    struct ClipRegion final : Op {
        static const auto kType = Type::ClipRegion;
        ClipRegion(const SkRegion& region, SkClipOp op) : region(region), op(op) {}
        SkRegion region;
        SkClipOp op;
        void draw(SkCanvas* c, const SkMatrix&) const { c->clipRegion(region, op); }
    };

    struct DrawPaint final : Op {
        static const auto kType = Type::DrawPaint;
        DrawPaint(const SkPaint& paint) : paint(paint) {}
        SkPaint paint;
        void draw(SkCanvas* c, const SkMatrix&) const { c->drawPaint(paint); }
    };
    struct DrawPath final : Op {
        static const auto kType = Type::DrawPath;
        DrawPath(const SkPath& path, const SkPaint& paint) : path(path), paint(paint) {}
        SkPath  path;
        SkPaint paint;
        void draw(SkCanvas* c, const SkMatrix&) const { c->drawPath(path, paint); }
    };
    struct DrawRect final : Op {
        static const auto kType = Type::DrawRect;
        DrawRect(const SkRect& rect, const SkPaint& paint) : rect(rect), paint(paint) {}
        SkRect  rect;
        SkPaint paint;
        void draw(SkCanvas* c, const SkMatrix&) const { c->drawRect(rect, paint); }
    };
    struct DrawEdgeAARect final : Op {
        static const auto kType = Type::DrawEdgeAARect;
        DrawEdgeAARect(const SkRect& rect, SkCanvas::QuadAAFlags aa, SkColor color,
                       SkBlendMode mode)
            : rect(rect), aa(aa), color(color), mode(mode) {}
        SkRect rect;
        SkCanvas::QuadAAFlags aa;
        SkColor color;
        SkBlendMode mode;
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->experimental_DrawEdgeAARectV1(rect, aa, color, mode);
        }
    };
    struct DrawRegion final : Op {
        static const auto kType = Type::DrawRegion;
        DrawRegion(const SkRegion& region, const SkPaint& paint) : region(region), paint(paint) {}
        SkRegion region;
        SkPaint  paint;
        void draw(SkCanvas* c, const SkMatrix&) const { c->drawRegion(region, paint); }
    };
    struct DrawOval final : Op {
        static const auto kType = Type::DrawOval;
        DrawOval(const SkRect& oval, const SkPaint& paint) : oval(oval), paint(paint) {}
        SkRect  oval;
        SkPaint paint;
        void draw(SkCanvas* c, const SkMatrix&) const { c->drawOval(oval, paint); }
    };
    struct DrawArc final : Op {
        static const auto kType = Type::DrawArc;
        DrawArc(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle, bool useCenter,
                const SkPaint& paint)
            : oval(oval), startAngle(startAngle), sweepAngle(sweepAngle), useCenter(useCenter)
            , paint(paint) {}
        SkRect  oval;
        SkScalar startAngle;
        SkScalar sweepAngle;
        bool useCenter;
        SkPaint paint;
        void draw(SkCanvas* c, const SkMatrix&) const { c->drawArc(oval, startAngle, sweepAngle,
                                                                   useCenter, paint); }
    };
    struct DrawRRect final : Op {
        static const auto kType = Type::DrawRRect;
        DrawRRect(const SkRRect& rrect, const SkPaint& paint) : rrect(rrect), paint(paint) {}
        SkRRect rrect;
        SkPaint paint;
        void draw(SkCanvas* c, const SkMatrix&) const { c->drawRRect(rrect, paint); }
    };
    struct DrawDRRect final : Op {
        static const auto kType = Type::DrawDRRect;
        DrawDRRect(const SkRRect& outer, const SkRRect& inner, const SkPaint& paint)
            : outer(outer), inner(inner), paint(paint) {}
        SkRRect outer, inner;
        SkPaint paint;
        void draw(SkCanvas* c, const SkMatrix&) const { c->drawDRRect(outer, inner, paint); }
    };

    struct DrawAnnotation final : Op {
        static const auto kType = Type::DrawAnnotation;
        DrawAnnotation(const SkRect& rect, SkData* value) : rect(rect), value(sk_ref_sp(value)) {}
        SkRect        rect;
        sk_sp<SkData> value;
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->drawAnnotation(rect, pod<char>(this), value.get());
        }
    };
    struct DrawDrawable final : Op {
        static const auto kType = Type::DrawDrawable;
        DrawDrawable(SkDrawable* drawable, const SkMatrix* matrix) : drawable(sk_ref_sp(drawable)) {
            if (matrix) { this->matrix = *matrix; }
        }
        sk_sp<SkDrawable> drawable;
        SkMatrix          matrix = SkMatrix::I();
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->drawDrawable(drawable.get(), &matrix);
        }
    };
    struct DrawPicture final : Op {
        static const auto kType = Type::DrawPicture;
        DrawPicture(const SkPicture* picture, const SkMatrix* matrix, const SkPaint* paint)
            : picture(sk_ref_sp(picture)) {
            if (matrix) { this->matrix = *matrix; }
            if (paint)  { this->paint  = *paint; has_paint = true; }
        }
        sk_sp<const SkPicture> picture;
        SkMatrix               matrix = SkMatrix::I();
        SkPaint                paint;
        bool                   has_paint = false;  // TODO: why is a default paint not the same?
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->drawPicture(picture.get(), &matrix, has_paint ? &paint : nullptr);
        }
    };

    struct DrawImage final : Op {
        static const auto kType = Type::DrawImage;
        DrawImage(sk_sp<const SkImage>&& image, SkScalar x, SkScalar y, const SkPaint* paint)
            : image(std::move(image)), x(x), y(y) {
            if (paint) { this->paint = *paint; }
        }
        sk_sp<const SkImage> image;
        SkScalar x,y;
        SkPaint paint;
        void draw(SkCanvas* c, const SkMatrix&) const { c->drawImage(image.get(), x,y, &paint); }
    };
    struct DrawImageNine final : Op {
        static const auto kType = Type::DrawImageNine;
        DrawImageNine(sk_sp<const SkImage>&& image,
                      const SkIRect& center, const SkRect& dst, const SkPaint* paint)
            : image(std::move(image)), center(center), dst(dst) {
            if (paint) { this->paint = *paint; }
        }
        sk_sp<const SkImage> image;
        SkIRect center;
        SkRect  dst;
        SkPaint paint;
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->drawImageNine(image.get(), center, dst, &paint);
        }
    };
    struct DrawImageRect final : Op {
        static const auto kType = Type::DrawImageRect;
        DrawImageRect(sk_sp<const SkImage>&& image, const SkRect* src, const SkRect& dst,
                      const SkPaint* paint, SkCanvas::SrcRectConstraint constraint)
            : image(std::move(image)), dst(dst), constraint(constraint) {
            this->src = src ? *src : SkRect::MakeIWH(image->width(), image->height());
            if (paint) { this->paint = *paint; }
        }
        sk_sp<const SkImage> image;
        SkRect src, dst;
        SkPaint paint;
        SkCanvas::SrcRectConstraint constraint;
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->drawImageRect(image.get(), src, dst, &paint, constraint);
        }
    };
    struct DrawImageLattice final : Op {
        static const auto kType = Type::DrawImageLattice;
        DrawImageLattice(sk_sp<const SkImage>&& image, int xs, int ys, int fs,
                         const SkIRect& src, const SkRect& dst, const SkPaint* paint)
            : image(std::move(image)), xs(xs), ys(ys), fs(fs), src(src), dst(dst) {
            if (paint) { this->paint = *paint; }
        }
        sk_sp<const SkImage> image;
        int                  xs, ys, fs;
        SkIRect              src;
        SkRect               dst;
        SkPaint              paint;
        void draw(SkCanvas* c, const SkMatrix&) const {
            auto xdivs = pod<int>(this, 0),
                 ydivs = pod<int>(this, xs*sizeof(int));
            auto colors = (0 == fs) ? nullptr :
                          pod<SkColor>(this, (xs+ys)*sizeof(int));
            auto flags = (0 == fs) ? nullptr :
                         pod<SkCanvas::Lattice::RectType>(this, (xs+ys)*sizeof(int)+
                                                          fs*sizeof(SkColor));
            c->drawImageLattice(image.get(), {xdivs, ydivs, flags, xs, ys, &src, colors}, dst,
                                &paint);
        }
    };
    struct DrawImageSet final : Op {
        static const auto kType = Type::DrawImageSet;
        DrawImageSet(const SkCanvas::ImageSetEntry set[], int count, SkFilterQuality quality,
                     SkBlendMode xfermode)
                : count(count), quality(quality), xfermode(xfermode), set(count) {
            std::copy_n(set, count, this->set.get());
        }
        int                                   count;
        SkFilterQuality                       quality;
        SkBlendMode                           xfermode;
        SkAutoTArray<SkCanvas::ImageSetEntry> set;
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->experimental_DrawImageSetV1(set.get(), count, quality, xfermode);
        }
    };
    struct DrawTextBlob final : Op {
        static const auto kType = Type::DrawTextBlob;
        DrawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y, const SkPaint& paint)
            : blob(sk_ref_sp(blob)), x(x), y(y), paint(paint) {}
        sk_sp<const SkTextBlob> blob;
        SkScalar x,y;
        SkPaint paint;
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->drawTextBlob(blob.get(), x,y, paint);
        }
    };

    struct DrawPatch final : Op {
        static const auto kType = Type::DrawPatch;
        DrawPatch(const SkPoint cubics[12], const SkColor colors[4], const SkPoint texs[4],
                  SkBlendMode bmode, const SkPaint& paint)
            : xfermode(bmode), paint(paint)
        {
            copy_v(this->cubics, cubics, 12);
            if (colors) { copy_v(this->colors, colors, 4); has_colors = true; }
            if (texs  ) { copy_v(this->texs  , texs  , 4); has_texs   = true; }
        }
        SkPoint           cubics[12];
        SkColor           colors[4];
        SkPoint           texs[4];
        SkBlendMode       xfermode;
        SkPaint           paint;
        bool              has_colors = false;
        bool              has_texs   = false;
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->drawPatch(cubics, has_colors ? colors : nullptr, has_texs ? texs : nullptr,
                         xfermode, paint);
        }
    };
    struct DrawPoints final : Op {
        static const auto kType = Type::DrawPoints;
        DrawPoints(SkCanvas::PointMode mode, size_t count, const SkPaint& paint)
            : mode(mode), count(count), paint(paint) {}
        SkCanvas::PointMode mode;
        size_t              count;
        SkPaint             paint;
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->drawPoints(mode, count, pod<SkPoint>(this), paint);
        }
    };
    struct DrawVertices final : Op {
        static const auto kType = Type::DrawVertices;
        DrawVertices(const SkVertices* v, int bc, SkBlendMode m, const SkPaint& p)
            : vertices(sk_ref_sp(const_cast<SkVertices*>(v)))
            , boneCount(bc)
            , mode(m)
            , paint(p) {}
        sk_sp<SkVertices> vertices;
        int boneCount;
        SkBlendMode mode;
        SkPaint paint;
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->drawVertices(vertices, pod<SkVertices::Bone>(this), boneCount, mode, paint);
        }
    };
    struct DrawAtlas final : Op {
        static const auto kType = Type::DrawAtlas;
        DrawAtlas(const SkImage* atlas, int count, SkBlendMode xfermode,
                  const SkRect* cull, const SkPaint* paint, bool has_colors)
            : atlas(sk_ref_sp(atlas)), count(count), xfermode(xfermode), has_colors(has_colors) {
            if (cull)  { this->cull  = *cull; }
            if (paint) { this->paint = *paint; }
        }
        sk_sp<const SkImage> atlas;
        int                  count;
        SkBlendMode          xfermode;
        SkRect               cull = kUnset;
        SkPaint              paint;
        bool                 has_colors;
        void draw(SkCanvas* c, const SkMatrix&) const {
            auto xforms = pod<SkRSXform>(this, 0);
            auto   texs = pod<SkRect>(this, count*sizeof(SkRSXform));
            auto colors = has_colors
                ? pod<SkColor>(this, count*(sizeof(SkRSXform) + sizeof(SkRect)))
                : nullptr;
            c->drawAtlas(atlas.get(), xforms, texs, colors, count, xfermode,
                         maybe_unset(cull), &paint);
        }
    };
    struct DrawShadowRec final : Op {
        static const auto kType = Type::DrawShadowRec;
        DrawShadowRec(const SkPath& path, const SkDrawShadowRec& rec)
            : fPath(path), fRec(rec)
        {}
        SkPath          fPath;
        SkDrawShadowRec fRec;
        void draw(SkCanvas* c, const SkMatrix&) const {
            c->private_draw_shadow_rec(fPath, fRec);
        }
    };
}

template <typename T, typename... Args>
void* SkLiteDL::push(size_t pod, Args&&... args) {
    size_t skip = SkAlignPtr(sizeof(T) + pod);
    SkASSERT(skip < (1<<24));
    if (fUsed + skip > fReserved) {
        static_assert(SkIsPow2(SKLITEDL_PAGE), "This math needs updating for non-pow2.");
        // Next greater multiple of SKLITEDL_PAGE.
        fReserved = (fUsed + skip + SKLITEDL_PAGE) & ~(SKLITEDL_PAGE-1);
        fBytes.realloc(fReserved);
    }
    SkASSERT(fUsed + skip <= fReserved);
    auto op = (T*)(fBytes.get() + fUsed);
    fUsed += skip;
    new (op) T{ std::forward<Args>(args)... };
    op->type = (uint32_t)T::kType;
    op->skip = skip;
    return op+1;
}

template <typename Fn, typename... Args>
inline void SkLiteDL::map(const Fn fns[], Args... args) const {
    auto end = fBytes.get() + fUsed;
    for (const uint8_t* ptr = fBytes.get(); ptr < end; ) {
        auto op = (const Op*)ptr;
        auto type = op->type;
        auto skip = op->skip;
        if (auto fn = fns[type]) {  // We replace no-op functions with nullptrs
            fn(op, args...);        // to avoid the overhead of a pointless call.
        }
        ptr += skip;
    }
}

void SkLiteDL::flush() { this->push<Flush>(0); }

void SkLiteDL::   save() { this->push   <Save>(0); }
void SkLiteDL::restore() { this->push<Restore>(0); }
void SkLiteDL::saveLayer(const SkRect* bounds, const SkPaint* paint,
                         const SkImageFilter* backdrop, const SkImage* clipMask,
                         const SkMatrix* clipMatrix, SkCanvas::SaveLayerFlags flags) {
    this->push<SaveLayer>(0, bounds, paint, backdrop, clipMask, clipMatrix, flags);
}
void SkLiteDL::saveBehind(const SkRect* subset) {
    this->push<SaveBehind>(0, subset);
}

void SkLiteDL::   concat(const SkMatrix& matrix)   { this->push   <Concat>(0, matrix); }
void SkLiteDL::setMatrix(const SkMatrix& matrix)   { this->push<SetMatrix>(0, matrix); }
void SkLiteDL::translate(SkScalar dx, SkScalar dy) { this->push<Translate>(0, dx, dy); }

void SkLiteDL::clipPath(const SkPath& path, SkClipOp op, bool aa) {
    this->push<ClipPath>(0, path, op, aa);
}
void SkLiteDL::clipRect(const SkRect& rect, SkClipOp op, bool aa) {
    this->push<ClipRect>(0, rect, op, aa);
}
void SkLiteDL::clipRRect(const SkRRect& rrect, SkClipOp op, bool aa) {
    this->push<ClipRRect>(0, rrect, op, aa);
}
void SkLiteDL::clipRegion(const SkRegion& region, SkClipOp op) {
    this->push<ClipRegion>(0, region, op);
}

void SkLiteDL::drawPaint(const SkPaint& paint) {
    this->push<DrawPaint>(0, paint);
}
void SkLiteDL::drawPath(const SkPath& path, const SkPaint& paint) {
    this->push<DrawPath>(0, path, paint);
}
void SkLiteDL::drawRect(const SkRect& rect, const SkPaint& paint) {
    this->push<DrawRect>(0, rect, paint);
}
void SkLiteDL::drawEdgeAARect(const SkRect& rect, SkCanvas::QuadAAFlags aa, SkColor color,
                              SkBlendMode mode) {
    this->push<DrawEdgeAARect>(0, rect, aa, color, mode);
}
void SkLiteDL::drawRegion(const SkRegion& region, const SkPaint& paint) {
    this->push<DrawRegion>(0, region, paint);
}
void SkLiteDL::drawOval(const SkRect& oval, const SkPaint& paint) {
    this->push<DrawOval>(0, oval, paint);
}
void SkLiteDL::drawArc(const SkRect& oval, SkScalar startAngle, SkScalar sweepAngle, bool useCenter,
                       const SkPaint& paint) {
    this->push<DrawArc>(0, oval, startAngle, sweepAngle, useCenter, paint);
}
void SkLiteDL::drawRRect(const SkRRect& rrect, const SkPaint& paint) {
    this->push<DrawRRect>(0, rrect, paint);
}
void SkLiteDL::drawDRRect(const SkRRect& outer, const SkRRect& inner, const SkPaint& paint) {
    this->push<DrawDRRect>(0, outer, inner, paint);
}

void SkLiteDL::drawAnnotation(const SkRect& rect, const char* key, SkData* value) {
    size_t bytes = strlen(key)+1;
    void* pod = this->push<DrawAnnotation>(bytes, rect, value);
    copy_v(pod, key,bytes);
}
void SkLiteDL::drawDrawable(SkDrawable* drawable, const SkMatrix* matrix) {
    this->push<DrawDrawable>(0, drawable, matrix);
}
void SkLiteDL::drawPicture(const SkPicture* picture,
                           const SkMatrix* matrix, const SkPaint* paint) {
    this->push<DrawPicture>(0, picture, matrix, paint);
}
void SkLiteDL::drawImage(sk_sp<const SkImage> image, SkScalar x, SkScalar y, const SkPaint* paint) {
    this->push<DrawImage>(0, std::move(image), x,y, paint);
}
void SkLiteDL::drawImageNine(sk_sp<const SkImage> image, const SkIRect& center,
                             const SkRect& dst, const SkPaint* paint) {
    this->push<DrawImageNine>(0, std::move(image), center, dst, paint);
}
void SkLiteDL::drawImageRect(sk_sp<const SkImage> image, const SkRect* src, const SkRect& dst,
                             const SkPaint* paint, SkCanvas::SrcRectConstraint constraint) {
    this->push<DrawImageRect>(0, std::move(image), src, dst, paint, constraint);
}
void SkLiteDL::drawImageLattice(sk_sp<const SkImage> image, const SkCanvas::Lattice& lattice,
                                const SkRect& dst, const SkPaint* paint) {
    int xs = lattice.fXCount, ys = lattice.fYCount;
    int fs = lattice.fRectTypes ? (xs + 1) * (ys + 1) : 0;
    size_t bytes = (xs + ys) * sizeof(int) + fs * sizeof(SkCanvas::Lattice::RectType)
                   + fs * sizeof(SkColor);
    SkASSERT(lattice.fBounds);
    void* pod = this->push<DrawImageLattice>(bytes, std::move(image), xs, ys, fs, *lattice.fBounds,
                                             dst, paint);
    copy_v(pod, lattice.fXDivs, xs,
                lattice.fYDivs, ys,
                lattice.fColors, fs,
                lattice.fRectTypes, fs);
}

void SkLiteDL::drawImageSet(const SkCanvas::ImageSetEntry set[], int count,
                            SkFilterQuality filterQuality, SkBlendMode mode) {
    this->push<DrawImageSet>(0, set, count, filterQuality, mode);
}

void SkLiteDL::drawTextBlob(const SkTextBlob* blob, SkScalar x, SkScalar y, const SkPaint& paint) {
    this->push<DrawTextBlob>(0, blob, x,y, paint);
}

void SkLiteDL::drawPatch(const SkPoint points[12], const SkColor colors[4], const SkPoint texs[4],
                         SkBlendMode bmode, const SkPaint& paint) {
    this->push<DrawPatch>(0, points, colors, texs, bmode, paint);
}
void SkLiteDL::drawPoints(SkCanvas::PointMode mode, size_t count, const SkPoint points[],
                          const SkPaint& paint) {
    void* pod = this->push<DrawPoints>(count*sizeof(SkPoint), mode, count, paint);
    copy_v(pod, points,count);
}
void SkLiteDL::drawVertices(const SkVertices* vertices, const SkVertices::Bone bones[],
                            int boneCount, SkBlendMode mode, const SkPaint& paint) {
    void* pod = this->push<DrawVertices>(boneCount * sizeof(SkVertices::Bone),
                                         vertices,
                                         boneCount,
                                         mode,
                                         paint);
    copy_v(pod, bones, boneCount);
}
void SkLiteDL::drawAtlas(const SkImage* atlas, const SkRSXform xforms[], const SkRect texs[],
                         const SkColor colors[], int count, SkBlendMode xfermode,
                         const SkRect* cull, const SkPaint* paint) {
    size_t bytes = count*(sizeof(SkRSXform) + sizeof(SkRect));
    if (colors) {
        bytes += count*sizeof(SkColor);
    }
    void* pod = this->push<DrawAtlas>(bytes,
                                      atlas, count, xfermode, cull, paint, colors != nullptr);
    copy_v(pod, xforms, count,
                  texs, count,
                colors, colors ? count : 0);
}
void SkLiteDL::drawShadowRec(const SkPath& path, const SkDrawShadowRec& rec) {
    this->push<DrawShadowRec>(0, path, rec);
}

typedef void(*draw_fn)(const void*,  SkCanvas*, const SkMatrix&);
typedef void(*void_fn)(const void*);

// All ops implement draw().
#define M(T) [](const void* op, SkCanvas* c, const SkMatrix& original) { \
    ((const T*)op)->draw(c, original);                                         \
},
static const draw_fn draw_fns[] = { TYPES(M) };
#undef M

// Most state ops (matrix, clip, save, restore) have a trivial destructor.
#define M(T) !std::is_trivially_destructible<T>::value \
    ? [](const void* op) { ((const T*)op)->~T(); }     \
    : (void_fn)nullptr,

static const void_fn dtor_fns[] = { TYPES(M) };
#undef M

void SkLiteDL::draw(SkCanvas* canvas) const {
    SkAutoCanvasRestore acr(canvas, false);
    this->map(draw_fns, canvas, canvas->getTotalMatrix());
}

SkLiteDL::~SkLiteDL() {
    this->reset();
}

void SkLiteDL::reset() {
    this->map(dtor_fns);

    // Leave fBytes and fReserved alone.
    fUsed   = 0;
}