cache.cpp

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    m_inPruneDeadResources = false;
}

void Cache::setCapacities(unsigned minDeadBytes, unsigned maxDeadBytes, unsigned totalBytes)
{
    ASSERT(minDeadBytes <= maxDeadBytes);
    ASSERT(maxDeadBytes <= totalBytes);
    m_minDeadCapacity = minDeadBytes;
    m_maxDeadCapacity = maxDeadBytes;
    m_capacity = totalBytes;
    prune();
}

void Cache::evict(CachedResource* resource)
{
    // The resource may have already been removed by someone other than our caller,
    // who needed a fresh copy for a reload. See <http://bugs.webkit.org/show_bug.cgi?id=12479#c6>.
    if (resource->inCache()) {
        if (!resource->isCacheValidator()) {
            // Notify all doc loaders that might be observing this object still that it has been
            // extracted from the set of resources.
            // No need to do this for cache validator resources, they are replaced automatically by using CachedResourceHandles.
            HashSet<DocLoader*>::iterator end = m_docLoaders.end();
            for (HashSet<DocLoader*>::iterator itr = m_docLoaders.begin(); itr != end; ++itr)
                (*itr)->removeCachedResource(resource);
        }
        
        // Remove from the resource map.
        m_resources.remove(resource->url());
        resource->setInCache(false);

        // Remove from the appropriate LRU list.
        removeFromLRUList(resource);
        removeFromLiveDecodedResourcesList(resource);

        // Subtract from our size totals.
        int delta = -static_cast<int>(resource->size());
        if (delta)
            adjustSize(resource->hasClients(), delta);
    } else
        ASSERT(m_resources.get(resource->url()) != resource);

    if (resource->canDelete())
        delete resource;
}

void Cache::addDocLoader(DocLoader* docLoader)
{
    m_docLoaders.add(docLoader);
}

void Cache::removeDocLoader(DocLoader* docLoader)
{
    m_docLoaders.remove(docLoader);
}

static inline unsigned fastLog2(unsigned i)
{
    unsigned log2 = 0;
    if (i & (i - 1))
        log2 += 1;
    if (i >> 16)
        log2 += 16, i >>= 16;
    if (i >> 8)
        log2 += 8, i >>= 8;
    if (i >> 4)
        log2 += 4, i >>= 4;
    if (i >> 2)
        log2 += 2, i >>= 2;
    if (i >> 1)
        log2 += 1;
    return log2;
}

Cache::LRUList* Cache::lruListFor(CachedResource* resource)
{
    unsigned accessCount = max(resource->accessCount(), 1U);
    unsigned queueIndex = fastLog2(resource->size() / accessCount);
#ifndef NDEBUG
    resource->m_lruIndex = queueIndex;
#endif
    if (m_allResources.size() <= queueIndex)
        m_allResources.grow(queueIndex + 1);
    return &m_allResources[queueIndex];
}

void Cache::removeFromLRUList(CachedResource* resource)
{
    // If we've never been accessed, then we're brand new and not in any list.
    if (resource->accessCount() == 0)
        return;

#ifndef NDEBUG
    unsigned oldListIndex = resource->m_lruIndex;
#endif

    LRUList* list = lruListFor(resource);

#ifndef NDEBUG
    // Verify that the list we got is the list we want.
    ASSERT(resource->m_lruIndex == oldListIndex);

    // Verify that we are in fact in this list.
    bool found = false;
    for (CachedResource* current = list->m_head; current; current = current->m_nextInAllResourcesList) {
        if (current == resource) {
            found = true;
            break;
        }
    }
    ASSERT(found);
#endif

    CachedResource* next = resource->m_nextInAllResourcesList;
    CachedResource* prev = resource->m_prevInAllResourcesList;
    
    if (next == 0 && prev == 0 && list->m_head != resource)
        return;
    
    resource->m_nextInAllResourcesList = 0;
    resource->m_prevInAllResourcesList = 0;
    
    if (next)
        next->m_prevInAllResourcesList = prev;
    else if (list->m_tail == resource)
        list->m_tail = prev;

    if (prev)
        prev->m_nextInAllResourcesList = next;
    else if (list->m_head == resource)
        list->m_head = next;
}

void Cache::insertInLRUList(CachedResource* resource)
{
    // Make sure we aren't in some list already.
    ASSERT(!resource->m_nextInAllResourcesList && !resource->m_prevInAllResourcesList);
    ASSERT(resource->inCache());
    ASSERT(resource->accessCount() > 0);
    
    LRUList* list = lruListFor(resource);

    resource->m_nextInAllResourcesList = list->m_head;
    if (list->m_head)
        list->m_head->m_prevInAllResourcesList = resource;
    list->m_head = resource;
    
    if (!resource->m_nextInAllResourcesList)
        list->m_tail = resource;
        
#ifndef NDEBUG
    // Verify that we are in now in the list like we should be.
    list = lruListFor(resource);
    bool found = false;
    for (CachedResource* current = list->m_head; current; current = current->m_nextInAllResourcesList) {
        if (current == resource) {
            found = true;
            break;
        }
    }
    ASSERT(found);
#endif

}

void Cache::resourceAccessed(CachedResource* resource)
{
    ASSERT(resource->inCache());
    
    // Need to make sure to remove before we increase the access count, since
    // the queue will possibly change.
    removeFromLRUList(resource);
    
    // If this is the first time the resource has been accessed, adjust the size of the cache to account for its initial size.
    if (!resource->accessCount())
        adjustSize(resource->hasClients(), resource->size());
    
    // Add to our access count.
    resource->increaseAccessCount();
    
    // Now insert into the new queue.
    insertInLRUList(resource);
}

void Cache::removeFromLiveDecodedResourcesList(CachedResource* resource)
{
    // If we've never been accessed, then we're brand new and not in any list.
    if (!resource->m_inLiveDecodedResourcesList)
        return;
    resource->m_inLiveDecodedResourcesList = false;

#ifndef NDEBUG
    // Verify that we are in fact in this list.
    bool found = false;
    for (CachedResource* current = m_liveDecodedResources.m_head; current; current = current->m_nextInLiveResourcesList) {
        if (current == resource) {
            found = true;
            break;
        }
    }
    ASSERT(found);
#endif

    CachedResource* next = resource->m_nextInLiveResourcesList;
    CachedResource* prev = resource->m_prevInLiveResourcesList;
    
    if (next == 0 && prev == 0 && m_liveDecodedResources.m_head != resource)
        return;
    
    resource->m_nextInLiveResourcesList = 0;
    resource->m_prevInLiveResourcesList = 0;
    
    if (next)
        next->m_prevInLiveResourcesList = prev;
    else if (m_liveDecodedResources.m_tail == resource)
        m_liveDecodedResources.m_tail = prev;

    if (prev)
        prev->m_nextInLiveResourcesList = next;
    else if (m_liveDecodedResources.m_head == resource)
        m_liveDecodedResources.m_head = next;
}

void Cache::insertInLiveDecodedResourcesList(CachedResource* resource)
{
    // Make sure we aren't in the list already.
    ASSERT(!resource->m_nextInLiveResourcesList && !resource->m_prevInLiveResourcesList && !resource->m_inLiveDecodedResourcesList);
    resource->m_inLiveDecodedResourcesList = true;

    resource->m_nextInLiveResourcesList = m_liveDecodedResources.m_head;
    if (m_liveDecodedResources.m_head)
        m_liveDecodedResources.m_head->m_prevInLiveResourcesList = resource;
    m_liveDecodedResources.m_head = resource;
    
    if (!resource->m_nextInLiveResourcesList)
        m_liveDecodedResources.m_tail = resource;
        
#ifndef NDEBUG
    // Verify that we are in now in the list like we should be.
    bool found = false;
    for (CachedResource* current = m_liveDecodedResources.m_head; current; current = current->m_nextInLiveResourcesList) {
        if (current == resource) {
            found = true;
            break;
        }
    }
    ASSERT(found);
#endif

}

void Cache::addToLiveResourcesSize(CachedResource* resource)
{
    m_liveSize += resource->size();
    m_deadSize -= resource->size();
}

void Cache::removeFromLiveResourcesSize(CachedResource* resource)
{
    m_liveSize -= resource->size();
    m_deadSize += resource->size();
}

void Cache::adjustSize(bool live, int delta)
{
    if (live) {
        ASSERT(delta >= 0 || ((int)m_liveSize + delta >= 0));
        m_liveSize += delta;
    } else {
        ASSERT(delta >= 0 || ((int)m_deadSize + delta >= 0));
        m_deadSize += delta;
    }
}

void Cache::TypeStatistic::addResource(CachedResource* o)
{
    bool purged = o->wasPurged();
    bool purgeable = o->isPurgeable() && !purged; 
    int pageSize = (o->encodedSize() + o->overheadSize() + 4095) & ~4095;
    count++;
    size += purged ? 0 : o->size(); 
    liveSize += o->hasClients() ? o->size() : 0;
    decodedSize += o->decodedSize();
    purgeableSize += purgeable ? pageSize : 0;
    purgedSize += purged ? pageSize : 0;
}

Cache::Statistics Cache::getStatistics()
{
    Statistics stats;
    CachedResourceMap::iterator e = m_resources.end();
    for (CachedResourceMap::iterator i = m_resources.begin(); i != e; ++i) {
        CachedResource* resource = i->second;
        switch (resource->type()) {
        case CachedResource::ImageResource:
            stats.images.addResource(resource);
            break;
        case CachedResource::CSSStyleSheet:
            stats.cssStyleSheets.addResource(resource);
            break;
        case CachedResource::Script:
            stats.scripts.addResource(resource);
            break;
#if ENABLE(XSLT)
        case CachedResource::XSLStyleSheet:
            stats.xslStyleSheets.addResource(resource);
            break;
#endif
        case CachedResource::FontResource:
            stats.fonts.addResource(resource);
            break;
#if ENABLE(XBL)
        case CachedResource::XBL:
            stats.xblDocs.addResource(resource)
            break;
#endif
        default:
            break;
        }
    }
    return stats;
}

void Cache::setDisabled(bool disabled)
{
    m_disabled = disabled;
    if (!m_disabled)
        return;

    for (;;) {
        CachedResourceMap::iterator i = m_resources.begin();
        if (i == m_resources.end())
            break;
        evict(i->second);
    }
}

#ifndef NDEBUG
void Cache::dumpStats()
{
    Statistics s = getStatistics();
    printf("%-11s %-11s %-11s %-11s %-11s %-11s %-11s\n", "", "Count", "Size", "LiveSize", "DecodedSize", "PurgeableSize", "PurgedSize");
    printf("%-11s %-11s %-11s %-11s %-11s %-11s %-11s\n", "-----------", "-----------", "-----------", "-----------", "-----------", "-----------", "-----------");
    printf("%-11s %11d %11d %11d %11d %11d %11d\n", "Images", s.images.count, s.images.size, s.images.liveSize, s.images.decodedSize, s.images.purgeableSize, s.images.purgedSize);
    printf("%-11s %11d %11d %11d %11d %11d %11d\n", "CSS", s.cssStyleSheets.count, s.cssStyleSheets.size, s.cssStyleSheets.liveSize, s.cssStyleSheets.decodedSize, s.cssStyleSheets.purgeableSize, s.cssStyleSheets.purgedSize);
#if ENABLE(XSLT)
    printf("%-11s %11d %11d %11d %11d %11d %11d\n", "XSL", s.xslStyleSheets.count, s.xslStyleSheets.size, s.xslStyleSheets.liveSize, s.xslStyleSheets.decodedSize, s.xslStyleSheets.purgeableSize, s.xslStyleSheets.purgedSize);
#endif
    printf("%-11s %11d %11d %11d %11d %11d %11d\n", "JavaScript", s.scripts.count, s.scripts.size, s.scripts.liveSize, s.scripts.decodedSize, s.scripts.purgeableSize, s.scripts.purgedSize);
    printf("%-11s %11d %11d %11d %11d %11d %11d\n", "Fonts", s.fonts.count, s.fonts.size, s.fonts.liveSize, s.fonts.decodedSize, s.fonts.purgeableSize, s.fonts.purgedSize);
    printf("%-11s %-11s %-11s %-11s %-11s %-11s %-11s\n\n", "-----------", "-----------", "-----------", "-----------", "-----------", "-----------", "-----------");
}

void Cache::dumpLRULists(bool includeLive) const
{
    printf("LRU-SP lists in eviction order (Kilobytes decoded, Kilobytes encoded, Access count, Referenced):\n");

    int size = m_allResources.size();
    for (int i = size - 1; i >= 0; i--) {
        printf("\n\nList %d: ", i);
        CachedResource* current = m_allResources[i].m_tail;
        while (current) {
            CachedResource* prev = current->m_prevInAllResourcesList;
            if (includeLive || !current->hasClients())
                printf("(%.1fK, %.1fK, %uA, %dR); ", current->decodedSize() / 1024.0f, (current->encodedSize() + current->overheadSize()) / 1024.0f, current->accessCount(), current->hasClients());
            current = prev;
        }
    }
}
#endif

} // namespace WebCore