src/core/SkPictureData.cpp

/*
 * Copyright 2011 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "src/core/SkPictureData.h"

#include "include/core/SkImageGenerator.h"
#include "include/core/SkTypeface.h"
#include "include/private/SkTo.h"
#include "src/core/SkAutoMalloc.h"
#include "src/core/SkPicturePriv.h"
#include "src/core/SkPictureRecord.h"
#include "src/core/SkReadBuffer.h"
#include "src/core/SkTextBlobPriv.h"
#include "src/core/SkVerticesPriv.h"
#include "src/core/SkWriteBuffer.h"

#include <new>

template <typename T> int SafeCount(const T* obj) {
    return obj ? obj->count() : 0;
}

SkPictureData::SkPictureData(const SkPictInfo& info)
    : fInfo(info) {}

void SkPictureData::initForPlayback() const {
    // ensure that the paths bounds are pre-computed
    for (int i = 0; i < fPaths.count(); i++) {
        fPaths[i].updateBoundsCache();
    }
}

SkPictureData::SkPictureData(const SkPictureRecord& record,
                             const SkPictInfo& info)
    : fPictures(record.getPictures())
    , fDrawables(record.getDrawables())
    , fTextBlobs(record.getTextBlobs())
    , fVertices(record.getVertices())
    , fImages(record.getImages())
    , fInfo(info) {

    fOpData = record.opData();

    fPaints  = record.fPaints;

    fPaths.reset(record.fPaths.count());
    record.fPaths.foreach([this](const SkPath& path, int n) {
        // These indices are logically 1-based, but we need to serialize them
        // 0-based to keep the deserializing SkPictureData::getPath() working.
        fPaths[n-1] = path;
    });

    this->initForPlayback();
}

///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////

#include "include/core/SkStream.h"

static size_t compute_chunk_size(SkFlattenable::Factory* array, int count) {
    size_t size = 4;  // for 'count'

    for (int i = 0; i < count; i++) {
        const char* name = SkFlattenable::FactoryToName(array[i]);
        if (nullptr == name || 0 == *name) {
            size += SkWStream::SizeOfPackedUInt(0);
        } else {
            size_t len = strlen(name);
            size += SkWStream::SizeOfPackedUInt(len);
            size += len;
        }
    }

    return size;
}

static void write_tag_size(SkWriteBuffer& buffer, uint32_t tag, size_t size) {
    buffer.writeUInt(tag);
    buffer.writeUInt(SkToU32(size));
}

static void write_tag_size(SkWStream* stream, uint32_t tag, size_t size) {
    stream->write32(tag);
    stream->write32(SkToU32(size));
}

void SkPictureData::WriteFactories(SkWStream* stream, const SkFactorySet& rec) {
    int count = rec.count();

    SkAutoSTMalloc<16, SkFlattenable::Factory> storage(count);
    SkFlattenable::Factory* array = (SkFlattenable::Factory*)storage.get();
    rec.copyToArray(array);

    size_t size = compute_chunk_size(array, count);

    // TODO: write_tag_size should really take a size_t
    write_tag_size(stream, SK_PICT_FACTORY_TAG, (uint32_t) size);
    SkDEBUGCODE(size_t start = stream->bytesWritten());
    stream->write32(count);

    for (int i = 0; i < count; i++) {
        const char* name = SkFlattenable::FactoryToName(array[i]);
        if (nullptr == name || 0 == *name) {
            stream->writePackedUInt(0);
        } else {
            size_t len = strlen(name);
            stream->writePackedUInt(len);
            stream->write(name, len);
        }
    }

    SkASSERT(size == (stream->bytesWritten() - start));
}

void SkPictureData::WriteTypefaces(SkWStream* stream, const SkRefCntSet& rec,
                                   const SkSerialProcs& procs) {
    int count = rec.count();

    write_tag_size(stream, SK_PICT_TYPEFACE_TAG, count);

    SkAutoSTMalloc<16, SkTypeface*> storage(count);
    SkTypeface** array = (SkTypeface**)storage.get();
    rec.copyToArray((SkRefCnt**)array);

    for (int i = 0; i < count; i++) {
        SkTypeface* tf = array[i];
        if (procs.fTypefaceProc) {
            auto data = procs.fTypefaceProc(tf, procs.fTypefaceCtx);
            if (data) {
                stream->write(data->data(), data->size());
                continue;
            }
        }
        array[i]->serialize(stream);
    }
}

void SkPictureData::flattenToBuffer(SkWriteBuffer& buffer, bool textBlobsOnly) const {
    int i, n;

    if (!textBlobsOnly) {
        if ((n = fPaints.count()) > 0) {
            write_tag_size(buffer, SK_PICT_PAINT_BUFFER_TAG, n);
            for (i = 0; i < n; i++) {
                buffer.writePaint(fPaints[i]);
            }
        }

        if ((n = fPaths.count()) > 0) {
            write_tag_size(buffer, SK_PICT_PATH_BUFFER_TAG, n);
            buffer.writeInt(n);
            for (int i = 0; i < n; i++) {
                buffer.writePath(fPaths[i]);
            }
        }
    }

    if (!fTextBlobs.empty()) {
        write_tag_size(buffer, SK_PICT_TEXTBLOB_BUFFER_TAG, fTextBlobs.count());
        for (const auto& blob : fTextBlobs) {
            SkTextBlobPriv::Flatten(*blob, buffer);
        }
    }

    if (!textBlobsOnly) {
        if (!fVertices.empty()) {
            write_tag_size(buffer, SK_PICT_VERTICES_BUFFER_TAG, fVertices.count());
            for (const auto& vert : fVertices) {
                vert->priv().encode(buffer);
            }
        }

        if (!fImages.empty()) {
            write_tag_size(buffer, SK_PICT_IMAGE_BUFFER_TAG, fImages.count());
            for (const auto& img : fImages) {
                buffer.writeImage(img.get());
            }
        }
    }
}

// SkPictureData::serialize() will write out paints, and then write out an array of typefaces
// (unique set). However, paint's serializer will respect SerialProcs, which can cause us to
// call that custom typefaceproc on *every* typeface, not just on the unique ones. To avoid this,
// we ignore the custom proc (here) when we serialize the paints, and then do respect it when
// we serialize the typefaces.
static SkSerialProcs skip_typeface_proc(const SkSerialProcs& procs) {
    SkSerialProcs newProcs = procs;
    newProcs.fTypefaceProc = nullptr;
    newProcs.fTypefaceCtx = nullptr;
    return newProcs;
}

// topLevelTypeFaceSet is null only on the top level call.
// This method is called recursively on every subpicture in two passes.
// textBlobsOnly serves to indicate that we are on the first pass and skip as much work as
// possible that is not relevant to collecting text blobs in topLevelTypeFaceSet
// TODO(nifong): dedupe typefaces and all other shared resources in a faster and more readable way.
void SkPictureData::serialize(SkWStream* stream, const SkSerialProcs& procs,
                              SkRefCntSet* topLevelTypeFaceSet, bool textBlobsOnly) const {
    // This can happen at pretty much any time, so might as well do it first.
    write_tag_size(stream, SK_PICT_READER_TAG, fOpData->size());
    stream->write(fOpData->bytes(), fOpData->size());

    // We serialize all typefaces into the typeface section of the top-level picture.
    SkRefCntSet localTypefaceSet;
    SkRefCntSet* typefaceSet = topLevelTypeFaceSet ? topLevelTypeFaceSet : &localTypefaceSet;

    // We delay serializing the bulk of our data until after we've serialized
    // factories and typefaces by first serializing to an in-memory write buffer.
    SkFactorySet factSet;  // buffer refs factSet, so factSet must come first.
    SkBinaryWriteBuffer buffer;
    buffer.setFactoryRecorder(sk_ref_sp(&factSet));
    buffer.setSerialProcs(skip_typeface_proc(procs));
    buffer.setTypefaceRecorder(sk_ref_sp(typefaceSet));
    this->flattenToBuffer(buffer, textBlobsOnly);

    // Pretend to serialize our sub-pictures for the side effect of filling typefaceSet
    // with typefaces from sub-pictures.
    struct DevNull: public SkWStream {
        DevNull() : fBytesWritten(0) {}
        size_t fBytesWritten;
        bool write(const void*, size_t size) override { fBytesWritten += size; return true; }
        size_t bytesWritten() const override { return fBytesWritten; }
    } devnull;
    for (const auto& pic : fPictures) {
        pic->serialize(&devnull, nullptr, typefaceSet, /*textBlobsOnly=*/ true);
    }
    if (textBlobsOnly) { return; } // return early from fake serialize

    // We need to write factories before we write the buffer.
    // We need to write typefaces before we write the buffer or any sub-picture.
    WriteFactories(stream, factSet);
    // Pass the original typefaceproc (if any) now that we're ready to actually serialize the
    // typefaces. We skipped this proc before, when we were serializing paints, so that the
    // paints would just write indices into our typeface set.
    WriteTypefaces(stream, *typefaceSet, procs);

    // Write the buffer.
    write_tag_size(stream, SK_PICT_BUFFER_SIZE_TAG, buffer.bytesWritten());
    buffer.writeToStream(stream);

    // Write sub-pictures by calling serialize again.
    if (!fPictures.empty()) {
        write_tag_size(stream, SK_PICT_PICTURE_TAG, fPictures.count());
        for (const auto& pic : fPictures) {
            pic->serialize(stream, &procs, typefaceSet, /*textBlobsOnly=*/ false);
        }
    }

    stream->write32(SK_PICT_EOF_TAG);
}

void SkPictureData::flatten(SkWriteBuffer& buffer) const {
    write_tag_size(buffer, SK_PICT_READER_TAG, fOpData->size());
    buffer.writeByteArray(fOpData->bytes(), fOpData->size());

    if (!fPictures.empty()) {
        write_tag_size(buffer, SK_PICT_PICTURE_TAG, fPictures.count());
        for (const auto& pic : fPictures) {
            SkPicturePriv::Flatten(pic, buffer);
        }
    }

    if (!fDrawables.empty()) {
        write_tag_size(buffer, SK_PICT_DRAWABLE_TAG, fDrawables.count());
        for (const auto& draw : fDrawables) {
            buffer.writeFlattenable(draw.get());
        }
    }

    // Write this picture playback's data into a writebuffer
    this->flattenToBuffer(buffer, false);
    buffer.write32(SK_PICT_EOF_TAG);
}

///////////////////////////////////////////////////////////////////////////////

bool SkPictureData::parseStreamTag(SkStream* stream,
                                   uint32_t tag,
                                   uint32_t size,
                                   const SkDeserialProcs& procs,
                                   SkTypefacePlayback* topLevelTFPlayback) {
    switch (tag) {
        case SK_PICT_READER_TAG:
            SkASSERT(nullptr == fOpData);
            fOpData = SkData::MakeFromStream(stream, size);
            if (!fOpData) {
                return false;
            }
            break;
        case SK_PICT_FACTORY_TAG: {
            if (!stream->readU32(&size)) { return false; }
            fFactoryPlayback = std::make_unique<SkFactoryPlayback>(size);
            for (size_t i = 0; i < size; i++) {
                SkString str;
                size_t len;
                if (!stream->readPackedUInt(&len)) { return false; }
                str.resize(len);
                if (stream->read(str.writable_str(), len) != len) {
                    return false;
                }
                fFactoryPlayback->base()[i] = SkFlattenable::NameToFactory(str.c_str());
            }
        } break;
        case SK_PICT_TYPEFACE_TAG: {
            fTFPlayback.setCount(size);
            for (uint32_t i = 0; i < size; ++i) {
                sk_sp<SkTypeface> tf;
                if (procs.fTypefaceProc) {
                    tf = procs.fTypefaceProc(&stream, sizeof(stream), procs.fTypefaceCtx);
                } else {
                    tf = SkTypeface::MakeDeserialize(stream);
                }
                if (!tf) {    // failed to deserialize
                    // fTFPlayback asserts it never has a null, so we plop in
                    // the default here.
                    tf = SkTypeface::MakeDefault();
                }
                fTFPlayback[i] = std::move(tf);
            }
        } break;
        case SK_PICT_PICTURE_TAG: {
            SkASSERT(fPictures.empty());
            fPictures.reserve_back(SkToInt(size));

            for (uint32_t i = 0; i < size; i++) {
                auto pic = SkPicture::MakeFromStream(stream, &procs, topLevelTFPlayback);
                if (!pic) {
                    return false;
                }
                fPictures.push_back(std::move(pic));
            }
        } break;
        case SK_PICT_BUFFER_SIZE_TAG: {
            SkAutoMalloc storage(size);
            if (stream->read(storage.get(), size) != size) {
                return false;
            }

            SkReadBuffer buffer(storage.get(), size);
            buffer.setVersion(fInfo.getVersion());

            if (!fFactoryPlayback) {
                return false;
            }
            fFactoryPlayback->setupBuffer(buffer);
            buffer.setDeserialProcs(procs);

            if (fTFPlayback.count() > 0) {
                // .skp files <= v43 have typefaces serialized with each sub picture.
                fTFPlayback.setupBuffer(buffer);
            } else {
                // Newer .skp files serialize all typefaces with the top picture.
                topLevelTFPlayback->setupBuffer(buffer);
            }

            while (!buffer.eof() && buffer.isValid()) {
                tag = buffer.readUInt();
                size = buffer.readUInt();
                this->parseBufferTag(buffer, tag, size);
            }
            if (!buffer.isValid()) {
                return false;
            }
        } break;
    }
    return true;    // success
}

static sk_sp<SkImage> create_image_from_buffer(SkReadBuffer& buffer) {
    return buffer.readImage();
}

static sk_sp<SkDrawable> create_drawable_from_buffer(SkReadBuffer& buffer) {
    return sk_sp<SkDrawable>((SkDrawable*)buffer.readFlattenable(SkFlattenable::kSkDrawable_Type));
}

// We need two types 'cause SkDrawable is const-variant.
template <typename T, typename U>
bool new_array_from_buffer(SkReadBuffer& buffer, uint32_t inCount,
                           SkTArray<sk_sp<T>>& array, sk_sp<U> (*factory)(SkReadBuffer&)) {
    if (!buffer.validate(array.empty() && SkTFitsIn<int>(inCount))) {
        return false;
    }
    if (0 == inCount) {
        return true;
    }

    for (uint32_t i = 0; i < inCount; ++i) {
        auto obj = factory(buffer);

        if (!buffer.validate(obj != nullptr)) {
            array.reset();
            return false;
        }

        array.push_back(std::move(obj));
    }

    return true;
}

void SkPictureData::parseBufferTag(SkReadBuffer& buffer, uint32_t tag, uint32_t size) {
    switch (tag) {
        case SK_PICT_PAINT_BUFFER_TAG: {
            if (!buffer.validate(SkTFitsIn<int>(size))) {
                return;
            }
            const int count = SkToInt(size);

            for (int i = 0; i < count; ++i) {
                // Do we need to keep an array of fFonts for legacy draws?
                if (!buffer.readPaint(&fPaints.push_back(), nullptr)) {
                    return;
                }
            }
        } break;
        case SK_PICT_PATH_BUFFER_TAG:
            if (size > 0) {
                const int count = buffer.readInt();
                if (!buffer.validate(count >= 0)) {
                    return;
                }
                for (int i = 0; i < count; i++) {
                    buffer.readPath(&fPaths.push_back());
                    if (!buffer.isValid()) {
                        return;
                    }
                }
            } break;
        case SK_PICT_TEXTBLOB_BUFFER_TAG:
            new_array_from_buffer(buffer, size, fTextBlobs, SkTextBlobPriv::MakeFromBuffer);
            break;
        case SK_PICT_VERTICES_BUFFER_TAG:
            new_array_from_buffer(buffer, size, fVertices, SkVerticesPriv::Decode);
            break;
        case SK_PICT_IMAGE_BUFFER_TAG:
            new_array_from_buffer(buffer, size, fImages, create_image_from_buffer);
            break;
        case SK_PICT_READER_TAG: {
            // Preflight check that we can initialize all data from the buffer
            // before allocating it.
            if (!buffer.validateCanReadN<uint8_t>(size)) {
                return;
            }
            auto data(SkData::MakeUninitialized(size));
            if (!buffer.readByteArray(data->writable_data(), size) ||
                !buffer.validate(nullptr == fOpData)) {
                return;
            }
            SkASSERT(nullptr == fOpData);
            fOpData = std::move(data);
        } break;
        case SK_PICT_PICTURE_TAG:
            new_array_from_buffer(buffer, size, fPictures, SkPicturePriv::MakeFromBuffer);
            break;
        case SK_PICT_DRAWABLE_TAG:
            new_array_from_buffer(buffer, size, fDrawables, create_drawable_from_buffer);
            break;
        default:
            buffer.validate(false); // The tag was invalid.
            break;
    }
}

SkPictureData* SkPictureData::CreateFromStream(SkStream* stream,
                                               const SkPictInfo& info,
                                               const SkDeserialProcs& procs,
                                               SkTypefacePlayback* topLevelTFPlayback) {
    std::unique_ptr<SkPictureData> data(new SkPictureData(info));
    if (!topLevelTFPlayback) {
        topLevelTFPlayback = &data->fTFPlayback;
    }

    if (!data->parseStream(stream, procs, topLevelTFPlayback)) {
        return nullptr;
    }
    return data.release();
}

SkPictureData* SkPictureData::CreateFromBuffer(SkReadBuffer& buffer,
                                               const SkPictInfo& info) {
    std::unique_ptr<SkPictureData> data(new SkPictureData(info));
    buffer.setVersion(info.getVersion());

    if (!data->parseBuffer(buffer)) {
        return nullptr;
    }
    return data.release();
}

bool SkPictureData::parseStream(SkStream* stream,
                                const SkDeserialProcs& procs,
                                SkTypefacePlayback* topLevelTFPlayback) {
    for (;;) {
        uint32_t tag;
        if (!stream->readU32(&tag)) { return false; }
        if (SK_PICT_EOF_TAG == tag) {
            break;
        }

        uint32_t size;
        if (!stream->readU32(&size)) { return false; }
        if (!this->parseStreamTag(stream, tag, size, procs, topLevelTFPlayback)) {
            return false; // we're invalid
        }
    }
    return true;
}

bool SkPictureData::parseBuffer(SkReadBuffer& buffer) {
    while (buffer.isValid()) {
        uint32_t tag = buffer.readUInt();
        if (SK_PICT_EOF_TAG == tag) {
            break;
        }
        this->parseBufferTag(buffer, tag, buffer.readUInt());
    }

    // Check that we encountered required tags
    if (!buffer.validate(this->opData() != nullptr)) {
        // If we didn't build any opData, we are invalid. Even an EmptyPicture allocates the
        // SkData for the ops (though its length may be zero).
        return false;
    }
    return true;
}

const SkPaint* SkPictureData::optionalPaint(SkReadBuffer* reader) const {
    int index = reader->readInt();
    if (index == 0) {
        return nullptr; // recorder wrote a zero for no paint (likely drawimage)
    }
    return reader->validate(index > 0 && index <= fPaints.count()) ?
        &fPaints[index - 1] : nullptr;
}

const SkPaint& SkPictureData::requiredPaint(SkReadBuffer* reader) const {
    const SkPaint* paint = this->optionalPaint(reader);
    if (reader->validate(paint != nullptr)) {
        return *paint;
    }
    static const SkPaint& stub = *(new SkPaint);
    return stub;
}