/*

 * Copyright 2007 The Android Open Source Project

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#include "include/core/SkPicture.h"

#include "include/core/SkData.h"

#include "include/core/SkPictureRecorder.h"

#include "include/core/SkSerialProcs.h"

#include "include/core/SkStream.h"

#include "include/private/base/SkTFitsIn.h"

#include "include/private/base/SkTo.h"

#include "src/base/SkMathPriv.h"

#include "src/core/SkCanvasPriv.h"

#include "src/core/SkPictureData.h"

#include "src/core/SkPicturePlayback.h"

#include "src/core/SkPicturePriv.h"

#include "src/core/SkPictureRecord.h"

#include "src/core/SkReadBuffer.h"

#include "src/core/SkResourceCache.h"

#include "src/core/SkStreamPriv.h"

#include "src/core/SkWriteBuffer.h"

#include <atomic>

#include <cstring>

#include <memory>

// When we read/write the SkPictInfo via a stream, we have a sentinel byte right after the info.

// Note: in the read/write buffer versions, we have a slightly different convention:

//      We have a sentinel int32_t:

//          0 : failure

//          1 : PictureData

//         <0 : -size of the custom data

enum {

    kFailure_TrailingStreamByteAfterPictInfo     = 0,   // nothing follows

    kPictureData_TrailingStreamByteAfterPictInfo = 1,   // SkPictureData follows

    kCustom_TrailingStreamByteAfterPictInfo      = 2,   // -size32 follows

};

/* SkPicture impl.  This handles generic responsibilities like unique IDs and serialization. */

SkPicture::SkPicture() {

    static std::atomic<uint32_t> nextID{1};

    do {

        fUniqueID = nextID.fetch_add(+1, std::memory_order_relaxed);

    } while (fUniqueID == 0);

}

SkPicture::~SkPicture() {

    if (fAddedToCache.load()) {

        SkResourceCache::PostPurgeSharedID(SkPicturePriv::MakeSharedID(fUniqueID));

    }

}

static const char kMagic[] = { 's', 'k', 'i', 'a', 'p', 'i', 'c', 't' };

SkPictInfo SkPicture::createHeader() const {

    SkPictInfo info;

    // Copy magic bytes at the beginning of the header

    static_assert(sizeof(kMagic) == 8, "");

    static_assert(sizeof(kMagic) == sizeof(info.fMagic), "");

    memcpy(info.fMagic, kMagic, sizeof(kMagic));

    // Set picture info after magic bytes in the header

    info.setVersion(SkPicturePriv::kCurrent_Version);

    info.fCullRect = this->cullRect();

    return info;

}

bool SkPicture::IsValidPictInfo(const SkPictInfo& info) {

    if (0 != memcmp(info.fMagic, kMagic, sizeof(kMagic))) {

        return false;

    }

    if (info.getVersion() < SkPicturePriv::kMin_Version ||

        info.getVersion() > SkPicturePriv::kCurrent_Version) {

        return false;

    }

    return true;

}

bool SkPicture::StreamIsSKP(SkStream* stream, SkPictInfo* pInfo) {

    if (!stream) {

        return false;

    }

    SkPictInfo info;

    SkASSERT(sizeof(kMagic) == sizeof(info.fMagic));

    if (stream->read(&info.fMagic, sizeof(kMagic)) != sizeof(kMagic)) {

        return false;

    }

    uint32_t version;

    if (!stream->readU32(&version)) { return false; }

    info.setVersion(version);

    if (!stream->readScalar(&info.fCullRect.fLeft  )) { return false; }

    if (!stream->readScalar(&info.fCullRect.fTop   )) { return false; }

    if (!stream->readScalar(&info.fCullRect.fRight )) { return false; }

    if (!stream->readScalar(&info.fCullRect.fBottom)) { return false; }

    if (pInfo) {

        *pInfo = info;

    }

    return IsValidPictInfo(info);

}

bool SkPicture_StreamIsSKP(SkStream* stream, SkPictInfo* pInfo) {

    return SkPicture::StreamIsSKP(stream, pInfo);

}

bool SkPicture::BufferIsSKP(SkReadBuffer* buffer, SkPictInfo* pInfo) {

    SkPictInfo info;

    SkASSERT(sizeof(kMagic) == sizeof(info.fMagic));

    if (!buffer->readByteArray(&info.fMagic, sizeof(kMagic))) {

        return false;

    }

    info.setVersion(buffer->readUInt());

    buffer->readRect(&info.fCullRect);

    if (IsValidPictInfo(info)) {

        if (pInfo) { *pInfo = info; }

        return true;

    }

    return false;

}

sk_sp<SkPicture> SkPicture::Forwardport(const SkPictInfo& info,

                                        const SkPictureData* data,

                                        SkReadBuffer* buffer) {

    if (!data) {

        return nullptr;

    }

    if (!data->opData()) {

        return nullptr;

    }

    SkPicturePlayback playback(data);

    SkPictureRecorder r;

    playback.draw(r.beginRecording(info.fCullRect), nullptr/*no callback*/, buffer);

    return r.finishRecordingAsPicture();

}

static const int kNestedSKPLimit = 100; // Arbitrarily set

sk_sp<SkPicture> SkPicture::MakeFromStream(SkStream* stream, const SkDeserialProcs* procs) {

    return MakeFromStreamPriv(stream, procs, nullptr, kNestedSKPLimit);

}

sk_sp<SkPicture> SkPicture::MakeFromData(const void* data, size_t size,

                                         const SkDeserialProcs* procs) {

    if (!data) {

        return nullptr;

    }

    SkMemoryStream stream(data, size);

    return MakeFromStreamPriv(&stream, procs, nullptr, kNestedSKPLimit);

}

sk_sp<SkPicture> SkPicture::MakeFromData(const SkData* data, const SkDeserialProcs* procs) {

    if (!data) {

        return nullptr;

    }

    SkMemoryStream stream(data->data(), data->size());

    return MakeFromStreamPriv(&stream, procs, nullptr, kNestedSKPLimit);

}

sk_sp<SkPicture> SkPicture::MakeFromStreamPriv(SkStream* stream, const SkDeserialProcs* procsPtr,

                                               SkTypefacePlayback* typefaces, int recursionLimit) {

    if (recursionLimit <= 0) {

        return nullptr;

    }

    SkPictInfo info;

    if (!StreamIsSKP(stream, &info)) {

        return nullptr;

    }

    SkDeserialProcs procs;

    if (procsPtr) {

        procs = *procsPtr;

    }

    uint8_t trailingStreamByteAfterPictInfo;

    if (!stream->readU8(&trailingStreamByteAfterPictInfo)) { return nullptr; }

    switch (trailingStreamByteAfterPictInfo) {

        case kPictureData_TrailingStreamByteAfterPictInfo: {

            std::unique_ptr<SkPictureData> data(

                    SkPictureData::CreateFromStream(stream, info, procs, typefaces,

                                                    recursionLimit));

            return Forwardport(info, data.get(), nullptr);

        }

        case kCustom_TrailingStreamByteAfterPictInfo: {

            int32_t ssize;

            if (!stream->readS32(&ssize) || ssize >= 0 || !procs.fPictureProc) {

                return nullptr;

            }

            size_t size = sk_negate_to_size_t(ssize);

            if (StreamRemainingLengthIsBelow(stream, size)) {

                return nullptr;

            }

            auto data = SkData::MakeUninitialized(size);

            if (stream->read(data->writable_data(), size) != size) {

                return nullptr;

            }

            return procs.fPictureProc(data->data(), size, procs.fPictureCtx);

        }

        default:    // fall out to error return

            break;

    }

    return nullptr;

}

sk_sp<SkPicture> SkPicturePriv::MakeFromBuffer(SkReadBuffer& buffer) {

    SkPictInfo info;

    if (!SkPicture::BufferIsSKP(&buffer, &info)) {

        return nullptr;

    }

    // size should be 0, 1, or negative

    int32_t ssize = buffer.read32();

    if (ssize < 0) {

        const SkDeserialProcs& procs = buffer.getDeserialProcs();

        if (!procs.fPictureProc) {

            return nullptr;

        }

        size_t size = sk_negate_to_size_t(ssize);

        return procs.fPictureProc(buffer.skip(size), size, procs.fPictureCtx);

    }

    if (ssize != 1) {

        // 1 is the magic 'size' that means SkPictureData follows

        return nullptr;

    }

   std::unique_ptr<SkPictureData> data(SkPictureData::CreateFromBuffer(buffer, info));

    return SkPicture::Forwardport(info, data.get(), &buffer);

}

SkPictureData* SkPicture::backport() const {

    SkPictInfo info = this->createHeader();

    SkPictureRecord rec(info.fCullRect.roundOut(), 0/*flags*/);

    rec.beginRecording();

        this->playback(&rec);

    rec.endRecording();

    return new SkPictureData(rec, info);

}

void SkPicture::serialize(SkWStream* stream, const SkSerialProcs* procs) const {

    this->serialize(stream, procs, nullptr);

}

sk_sp<SkData> SkPicture::serialize(const SkSerialProcs* procs) const {

    SkDynamicMemoryWStream stream;

    this->serialize(&stream, procs, nullptr);

    return stream.detachAsData();

}

static sk_sp<SkData> custom_serialize(const SkPicture* picture, const SkSerialProcs& procs) {

    if (procs.fPictureProc) {

        auto data = procs.fPictureProc(const_cast<SkPicture*>(picture), procs.fPictureCtx);

        if (data) {

            size_t size = data->size();

            if (!SkTFitsIn<int32_t>(size) || size <= 1) {

                return SkData::MakeEmpty();

            }

            return data;

        }

    }

    return nullptr;

}

static bool write_pad32(SkWStream* stream, const void* data, size_t size) {

    if (!stream->write(data, size)) {

        return false;

    }

    if (size & 3) {

        uint32_t zero = 0;

        return stream->write(&zero, 4 - (size & 3));

    }

    return true;

}

// Private serialize.

// SkPictureData::serialize makes a first pass on all subpictures, indicated by textBlobsOnly=true,

// to fill typefaceSet.

void SkPicture::serialize(SkWStream* stream, const SkSerialProcs* procsPtr,

                          SkRefCntSet* typefaceSet, bool textBlobsOnly) const {

    SkSerialProcs procs;

    if (procsPtr) {

        procs = *procsPtr;

    }

    SkPictInfo info = this->createHeader();

    stream->write(&info, sizeof(info));

    if (auto custom = custom_serialize(this, procs)) {

        int32_t size = SkToS32(custom->size());

        if (size == 0) {

            stream->write8(kFailure_TrailingStreamByteAfterPictInfo);

            return;

        }

        stream->write8(kCustom_TrailingStreamByteAfterPictInfo);

        stream->write32(-size);    // negative for custom format

        write_pad32(stream, custom->data(), size);

        return;

    }

    std::unique_ptr<SkPictureData> data(this->backport());

    if (data) {

        stream->write8(kPictureData_TrailingStreamByteAfterPictInfo);

        data->serialize(stream, procs, typefaceSet, textBlobsOnly);

    } else {

        stream->write8(kFailure_TrailingStreamByteAfterPictInfo);

    }

}

void SkPicturePriv::Flatten(const sk_sp<const SkPicture> picture, SkWriteBuffer& buffer) {

    SkPictInfo info = picture->createHeader();

    std::unique_ptr<SkPictureData> data(picture->backport());

    buffer.writeByteArray(&info.fMagic, sizeof(info.fMagic));

    buffer.writeUInt(info.getVersion());

    buffer.writeRect(info.fCullRect);

    if (auto custom = custom_serialize(picture.get(), buffer.serialProcs())) {

        int32_t size = SkToS32(custom->size());

        buffer.write32(-size);    // negative for custom format

        buffer.writePad32(custom->data(), size);

        return;

    }

    if (data) {

        buffer.write32(1); // special size meaning SkPictureData

        data->flatten(buffer);

    } else {

        buffer.write32(0); // signal no content

    }

}

sk_sp<SkPicture> SkPicture::MakePlaceholder(SkRect cull) {

    struct Placeholder : public SkPicture {

          explicit Placeholder(SkRect cull) : fCull(cull) {}

          void playback(SkCanvas*, AbortCallback*) const override { }

          // approximateOpCount() needs to be greater than kMaxPictureOpsToUnrollInsteadOfRef

          // (SkCanvasPriv.h) to avoid unrolling this into a parent picture.

          int approximateOpCount(bool) const override {

              return kMaxPictureOpsToUnrollInsteadOfRef+1;

          }

          size_t approximateBytesUsed() const override { return sizeof(*this); }

          SkRect cullRect()             const override { return fCull; }

          SkRect fCull;

    };

    return sk_make_sp<Placeholder>(cull);

}