/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "GrResourceProvider.h"

#include "GrBuffer.h"
#include "GrCaps.h"
#include "GrGpu.h"
#include "GrPathRendering.h"
#include "GrRenderTarget.h"
#include "GrRenderTargetPriv.h"
#include "GrResourceCache.h"
#include "GrResourceKey.h"
#include "GrStencilAttachment.h"
#include "GrTexturePriv.h"
#include "../private/GrSingleOwner.h"
#include "SkMathPriv.h"

GR_DECLARE_STATIC_UNIQUE_KEY(gQuadIndexBufferKey);

const int GrResourceProvider::kMinScratchTextureSize = 16;

#define ASSERT_SINGLE_OWNER \
    SkDEBUGCODE(GrSingleOwner::AutoEnforce debug_SingleOwner(fSingleOwner);)

GrResourceProvider::GrResourceProvider(GrGpu* gpu, GrResourceCache* cache, GrSingleOwner* owner)
        : fCache(cache)
        , fGpu(gpu)
#ifdef SK_DEBUG
        , fSingleOwner(owner)
#endif
        {
    GR_DEFINE_STATIC_UNIQUE_KEY(gQuadIndexBufferKey);
    fQuadIndexBufferKey = gQuadIndexBufferKey;
}


GrTexture* GrResourceProvider::createMipMappedTexture(const GrSurfaceDesc& desc,
                                                      SkBudgeted budgeted, const GrMipLevel* texels,
                                                      int mipLevelCount, uint32_t flags) {
    ASSERT_SINGLE_OWNER

    if (this->isAbandoned()) {
        return nullptr;
    }
    if (mipLevelCount && !texels) {
        return nullptr;
    }
    for (int i = 0; i < mipLevelCount; ++i) {
        if (!texels[i].fPixels) {
            return nullptr;
        }
    }
    if (mipLevelCount > 1 && GrPixelConfigIsSint(desc.fConfig)) {
        return nullptr;
    }
    if ((desc.fFlags & kRenderTarget_GrSurfaceFlag) &&
        !fGpu->caps()->isConfigRenderable(desc.fConfig, desc.fSampleCnt > 0)) {
        return nullptr;
    }
    if (!GrPixelConfigIsCompressed(desc.fConfig)) {
        if (mipLevelCount < 2) {
            flags |= kExact_Flag | kNoCreate_Flag;
            if (GrTexture* texture = this->refScratchTexture(desc, flags)) {
                if (!mipLevelCount ||
                    texture->writePixels(0, 0, desc.fWidth, desc.fHeight, desc.fConfig,
                                         texels[0].fPixels, texels[0].fRowBytes)) {
                    if (SkBudgeted::kNo == budgeted) {
                        texture->resourcePriv().makeUnbudgeted();
                    }
                    return texture;
                }
                texture->unref();
            }
        }
    }

    SkTArray<GrMipLevel> texelsShallowCopy(mipLevelCount);
    for (int i = 0; i < mipLevelCount; ++i) {
        texelsShallowCopy.push_back(texels[i]);
    }
    return fGpu->createTexture(desc, budgeted, texelsShallowCopy);
}

GrTexture* GrResourceProvider::createTexture(const GrSurfaceDesc& desc, SkBudgeted budgeted,
                                             const void* srcData, size_t rowBytes, uint32_t flags) {
    GrMipLevel tempTexels;
    GrMipLevel* texels = nullptr;
    int levelCount = 0;
    if (srcData) {
        tempTexels.fPixels = srcData;
        tempTexels.fRowBytes = rowBytes;
        texels = &tempTexels;
        levelCount = 1;
    }
    return this->createMipMappedTexture(desc, budgeted, texels, levelCount, flags);
}

GrTexture* GrResourceProvider::createApproxTexture(const GrSurfaceDesc& desc, uint32_t flags) {
    ASSERT_SINGLE_OWNER
    SkASSERT(0 == flags || kNoPendingIO_Flag == flags);
    return this->internalCreateApproxTexture(desc, flags);
}

GrTexture* GrResourceProvider::internalCreateApproxTexture(const GrSurfaceDesc& desc,
                                                           uint32_t scratchFlags) {
    ASSERT_SINGLE_OWNER
    if (this->isAbandoned()) {
        return nullptr;
    }
    // Currently we don't recycle compressed textures as scratch.
    if (GrPixelConfigIsCompressed(desc.fConfig)) {
        return nullptr;
    } else {
        return this->refScratchTexture(desc, scratchFlags);
    }
}

GrTexture* GrResourceProvider::refScratchTexture(const GrSurfaceDesc& inDesc,
                                                 uint32_t flags) {
    ASSERT_SINGLE_OWNER
    SkASSERT(!this->isAbandoned());
    SkASSERT(!GrPixelConfigIsCompressed(inDesc.fConfig));

    SkTCopyOnFirstWrite<GrSurfaceDesc> desc(inDesc);

    if (fGpu->caps()->reuseScratchTextures() || (desc->fFlags & kRenderTarget_GrSurfaceFlag)) {
        if (!(kExact_Flag & flags)) {
            // bin by pow2 with a reasonable min
            GrSurfaceDesc* wdesc = desc.writable();
            wdesc->fWidth  = SkTMax(kMinScratchTextureSize, GrNextPow2(desc->fWidth));
            wdesc->fHeight = SkTMax(kMinScratchTextureSize, GrNextPow2(desc->fHeight));
        }

        GrScratchKey key;
        GrTexturePriv::ComputeScratchKey(*desc, &key);
        uint32_t scratchFlags = 0;
        if (kNoPendingIO_Flag & flags) {
            scratchFlags = GrResourceCache::kRequireNoPendingIO_ScratchFlag;
        } else  if (!(desc->fFlags & kRenderTarget_GrSurfaceFlag)) {
            // If it is not a render target then it will most likely be populated by
            // writePixels() which will trigger a flush if the texture has pending IO.
            scratchFlags = GrResourceCache::kPreferNoPendingIO_ScratchFlag;
        }
        GrGpuResource* resource = fCache->findAndRefScratchResource(key,
                                                                   GrSurface::WorstCaseSize(*desc),
                                                                   scratchFlags);
        if (resource) {
            GrSurface* surface = static_cast<GrSurface*>(resource);
            GrRenderTarget* rt = surface->asRenderTarget();
            if (rt && fGpu->caps()->discardRenderTargetSupport()) {
                rt->discard();
            }
            return surface->asTexture();
        }
    }

    if (!(kNoCreate_Flag & flags)) {
        return fGpu->createTexture(*desc, SkBudgeted::kYes);
    }

    return nullptr;
}

sk_sp<GrTexture> GrResourceProvider::wrapBackendTexture(const GrBackendTextureDesc& desc,
                                                        GrWrapOwnership ownership) {
    ASSERT_SINGLE_OWNER
    if (this->isAbandoned()) {
        return nullptr;
    }
    return fGpu->wrapBackendTexture(desc, ownership);
}

sk_sp<GrRenderTarget> GrResourceProvider::wrapBackendRenderTarget(
        const GrBackendRenderTargetDesc& desc)
{
    ASSERT_SINGLE_OWNER
    return this->isAbandoned() ? nullptr
                               : fGpu->wrapBackendRenderTarget(desc, kBorrow_GrWrapOwnership);
}

void GrResourceProvider::assignUniqueKeyToResource(const GrUniqueKey& key,
                                                   GrGpuResource* resource) {
    ASSERT_SINGLE_OWNER
    if (this->isAbandoned() || !resource) {
        return;
    }
    resource->resourcePriv().setUniqueKey(key);
}

GrGpuResource* GrResourceProvider::findAndRefResourceByUniqueKey(const GrUniqueKey& key) {
    ASSERT_SINGLE_OWNER
    return this->isAbandoned() ? nullptr : fCache->findAndRefUniqueResource(key);
}

GrTexture* GrResourceProvider::findAndRefTextureByUniqueKey(const GrUniqueKey& key) {
    ASSERT_SINGLE_OWNER
    GrGpuResource* resource = this->findAndRefResourceByUniqueKey(key);
    if (resource) {
        GrTexture* texture = static_cast<GrSurface*>(resource)->asTexture();
        SkASSERT(texture);
        return texture;
    }
    return NULL;
}

const GrBuffer* GrResourceProvider::createInstancedIndexBuffer(const uint16_t* pattern,
                                                               int patternSize,
                                                               int reps,
                                                               int vertCount,
                                                               const GrUniqueKey& key) {
    size_t bufferSize = patternSize * reps * sizeof(uint16_t);

    // This is typically used in GrMeshDrawOps, so we assume kNoPendingIO.
    GrBuffer* buffer = this->createBuffer(bufferSize, kIndex_GrBufferType, kStatic_GrAccessPattern,
                                          kNoPendingIO_Flag);
    if (!buffer) {
        return nullptr;
    }
    uint16_t* data = (uint16_t*) buffer->map();
    bool useTempData = (nullptr == data);
    if (useTempData) {
        data = new uint16_t[reps * patternSize];
    }
    for (int i = 0; i < reps; ++i) {
        int baseIdx = i * patternSize;
        uint16_t baseVert = (uint16_t)(i * vertCount);
        for (int j = 0; j < patternSize; ++j) {
            data[baseIdx+j] = baseVert + pattern[j];
        }
    }
    if (useTempData) {
        if (!buffer->updateData(data, bufferSize)) {
            buffer->unref();
            return nullptr;
        }
        delete[] data;
    } else {
        buffer->unmap();
    }
    this->assignUniqueKeyToResource(key, buffer);
    return buffer;
}

const GrBuffer* GrResourceProvider::createQuadIndexBuffer() {
    static const int kMaxQuads = 1 << 12; // max possible: (1 << 14) - 1;
    GR_STATIC_ASSERT(4 * kMaxQuads <= 65535);
    static const uint16_t kPattern[] = { 0, 1, 2, 0, 2, 3 };

    return this->createInstancedIndexBuffer(kPattern, 6, kMaxQuads, 4, fQuadIndexBufferKey);
}

GrPath* GrResourceProvider::createPath(const SkPath& path, const GrStyle& style) {
    SkASSERT(this->gpu()->pathRendering());
    return this->gpu()->pathRendering()->createPath(path, style);
}

GrPathRange* GrResourceProvider::createPathRange(GrPathRange::PathGenerator* gen,
                                                 const GrStyle& style) {
    SkASSERT(this->gpu()->pathRendering());
    return this->gpu()->pathRendering()->createPathRange(gen, style);
}

GrPathRange* GrResourceProvider::createGlyphs(const SkTypeface* tf,
                                              const SkScalerContextEffects& effects,
                                              const SkDescriptor* desc,
                                              const GrStyle& style) {

    SkASSERT(this->gpu()->pathRendering());
    return this->gpu()->pathRendering()->createGlyphs(tf, effects, desc, style);
}

GrBuffer* GrResourceProvider::createBuffer(size_t size, GrBufferType intendedType,
                                           GrAccessPattern accessPattern, uint32_t flags,
                                           const void* data) {
    if (this->isAbandoned()) {
        return nullptr;
    }
    if (kDynamic_GrAccessPattern != accessPattern) {
        return this->gpu()->createBuffer(size, intendedType, accessPattern, data);
    }
    if (!(flags & kRequireGpuMemory_Flag) &&
        this->gpu()->caps()->preferClientSideDynamicBuffers() &&
        GrBufferTypeIsVertexOrIndex(intendedType) &&
        kDynamic_GrAccessPattern == accessPattern) {
        return GrBuffer::CreateCPUBacked(this->gpu(), size, intendedType, data);
    }

    // bin by pow2 with a reasonable min
    static const size_t MIN_SIZE = 1 << 12;
    size_t allocSize = SkTMax(MIN_SIZE, GrNextSizePow2(size));

    GrScratchKey key;
    GrBuffer::ComputeScratchKeyForDynamicVBO(allocSize, intendedType, &key);
    uint32_t scratchFlags = 0;
    if (flags & kNoPendingIO_Flag) {
        scratchFlags = GrResourceCache::kRequireNoPendingIO_ScratchFlag;
    } else {
        scratchFlags = GrResourceCache::kPreferNoPendingIO_ScratchFlag;
    }
    GrBuffer* buffer = static_cast<GrBuffer*>(
        this->cache()->findAndRefScratchResource(key, allocSize, scratchFlags));
    if (!buffer) {
        buffer = this->gpu()->createBuffer(allocSize, intendedType, kDynamic_GrAccessPattern);
        if (!buffer) {
            return nullptr;
        }
    }
    if (data) {
        buffer->updateData(data, size);
    }
    SkASSERT(!buffer->isCPUBacked()); // We should only cache real VBOs.
    return buffer;
}

GrStencilAttachment* GrResourceProvider::attachStencilAttachment(GrRenderTarget* rt) {
    SkASSERT(rt);
    if (rt->renderTargetPriv().getStencilAttachment()) {
        return rt->renderTargetPriv().getStencilAttachment();
    }

    if (!rt->wasDestroyed() && rt->canAttemptStencilAttachment()) {
        GrUniqueKey sbKey;

        int width = rt->width();
        int height = rt->height();
#if 0
        if (this->caps()->oversizedStencilSupport()) {
            width  = SkNextPow2(width);
            height = SkNextPow2(height);
        }
#endif
        bool newStencil = false;
        GrStencilAttachment::ComputeSharedStencilAttachmentKey(width, height,
                                                               rt->numStencilSamples(), &sbKey);
        GrStencilAttachment* stencil = static_cast<GrStencilAttachment*>(
            this->findAndRefResourceByUniqueKey(sbKey));
        if (!stencil) {
            // Need to try and create a new stencil
            stencil = this->gpu()->createStencilAttachmentForRenderTarget(rt, width, height);
            if (stencil) {
                this->assignUniqueKeyToResource(sbKey, stencil);
                newStencil = true;
            }
        }
        if (rt->renderTargetPriv().attachStencilAttachment(stencil)) {
            if (newStencil) {
                // Right now we're clearing the stencil attachment here after it is
                // attached to a RT for the first time. When we start matching
                // stencil buffers with smaller color targets this will no longer
                // be correct because it won't be guaranteed to clear the entire
                // sb.
                // We used to clear down in the GL subclass using a special purpose
                // FBO. But iOS doesn't allow a stencil-only FBO. It reports unsupported
                // FBO status.
                this->gpu()->clearStencil(rt);
            }
        }
    }
    return rt->renderTargetPriv().getStencilAttachment();
}

sk_sp<GrRenderTarget> GrResourceProvider::wrapBackendTextureAsRenderTarget(
        const GrBackendTextureDesc& desc)
{
    if (this->isAbandoned()) {
        return nullptr;
    }
    return this->gpu()->wrapBackendTextureAsRenderTarget(desc);
}