third_party/WebKit/Source/core/fetch/FontResource.cpp

/*
 * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
 * Copyright (C) 2009 Torch Mobile, Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "core/fetch/FontResource.h"

#include "core/fetch/FetchRequest.h"
#include "core/fetch/ResourceClientOrObserverWalker.h"
#include "core/fetch/ResourceFetcher.h"
#include "platform/Histogram.h"
#include "platform/SharedBuffer.h"
#include "platform/fonts/FontCustomPlatformData.h"
#include "platform/fonts/FontPlatformData.h"
#include "wtf/CurrentTime.h"

namespace blink {

// Durations of font-display periods.
// https://tabatkins.github.io/specs/css-font-display/#font-display-desc
static const double fontLoadWaitShortLimitSec = 0.1;
static const double fontLoadWaitLongLimitSec = 3.0;

enum FontPackageFormat {
    PackageFormatUnknown,
    PackageFormatSFNT,
    PackageFormatWOFF,
    PackageFormatWOFF2,
    PackageFormatSVG,
    PackageFormatEnumMax
};

static FontPackageFormat packageFormatOf(SharedBuffer* buffer)
{
    if (buffer->size() < 4)
        return PackageFormatUnknown;

    const char* data = buffer->data();
    if (data[0] == 'w' && data[1] == 'O' && data[2] == 'F' && data[3] == 'F')
        return PackageFormatWOFF;
    if (data[0] == 'w' && data[1] == 'O' && data[2] == 'F' && data[3] == '2')
        return PackageFormatWOFF2;
    return PackageFormatSFNT;
}

static void recordPackageFormatHistogram(FontPackageFormat format)
{
    DEFINE_THREAD_SAFE_STATIC_LOCAL(EnumerationHistogram, packageFormatHistogram, new EnumerationHistogram("WebFont.PackageFormat", PackageFormatEnumMax));
    packageFormatHistogram.count(format);
}

FontResource* FontResource::fetch(FetchRequest& request, ResourceFetcher* fetcher)
{
    ASSERT(request.resourceRequest().frameType() == WebURLRequest::FrameTypeNone);
    request.mutableResourceRequest().setRequestContext(WebURLRequest::RequestContextFont);
    return toFontResource(fetcher->requestResource(request, FontResourceFactory()));
}

FontResource::FontResource(const ResourceRequest& resourceRequest, const ResourceLoaderOptions& options)
    : Resource(resourceRequest, Font, options)
    , m_loadLimitState(UnderLimit)
    , m_corsFailed(false)
    , m_fontLoadShortLimitTimer(this, &FontResource::fontLoadShortLimitCallback)
    , m_fontLoadLongLimitTimer(this, &FontResource::fontLoadLongLimitCallback)
{
}

FontResource::~FontResource()
{
}

void FontResource::didAddClient(ResourceClient* c)
{
    ASSERT(FontResourceClient::isExpectedType(c));
    Resource::didAddClient(c);
    if (m_loadLimitState == ShortLimitExceeded || m_loadLimitState == LongLimitExceeded)
        static_cast<FontResourceClient*>(c)->fontLoadShortLimitExceeded(this);
    if (m_loadLimitState == LongLimitExceeded)
        static_cast<FontResourceClient*>(c)->fontLoadLongLimitExceeded(this);
}

void FontResource::setRevalidatingRequest(const ResourceRequest& request)
{
    // Reload will use the same object, and needs to reset |m_loadLimitState|
    // before any didAddClient() is called again.
    m_loadLimitState = UnderLimit;
    Resource::setRevalidatingRequest(request);
}

void FontResource::startLoadLimitTimersIfNeeded()
{
    ASSERT(!stillNeedsLoad());
    if (isLoaded() || m_fontLoadLongLimitTimer.isActive())
        return;
    ASSERT(m_loadLimitState == UnderLimit);
    m_fontLoadShortLimitTimer.startOneShot(fontLoadWaitShortLimitSec, BLINK_FROM_HERE);
    m_fontLoadLongLimitTimer.startOneShot(fontLoadWaitLongLimitSec, BLINK_FROM_HERE);
}

bool FontResource::ensureCustomFontData()
{
    if (!m_fontData && !errorOccurred() && !isLoading()) {
        if (m_data)
            m_fontData = FontCustomPlatformData::create(m_data.get(), m_otsParsingMessage);

        if (m_fontData) {
            recordPackageFormatHistogram(packageFormatOf(m_data.get()));
        } else {
            setStatus(DecodeError);
            recordPackageFormatHistogram(PackageFormatUnknown);
        }
    }
    return m_fontData.get();
}

FontPlatformData FontResource::platformDataFromCustomData(float size, bool bold, bool italic, FontOrientation orientation)
{
    ASSERT(m_fontData);
    return m_fontData->fontPlatformData(size, bold, italic, orientation);
}

bool FontResource::isSafeToUnlock() const
{
    return m_data->hasOneRef();
}

void FontResource::fontLoadShortLimitCallback(Timer<FontResource>*)
{
    if (!isLoading())
        return;
    ASSERT(m_loadLimitState == UnderLimit);
    m_loadLimitState = ShortLimitExceeded;
    ResourceClientWalker<FontResourceClient> walker(m_clients);
    while (FontResourceClient* client = walker.next())
        client->fontLoadShortLimitExceeded(this);
}

void FontResource::fontLoadLongLimitCallback(Timer<FontResource>*)
{
    if (!isLoading())
        return;
    ASSERT(m_loadLimitState == ShortLimitExceeded);
    m_loadLimitState = LongLimitExceeded;
    ResourceClientWalker<FontResourceClient> walker(m_clients);
    while (FontResourceClient* client = walker.next())
        client->fontLoadLongLimitExceeded(this);
}

void FontResource::allClientsAndObserversRemoved()
{
    m_fontData.reset();
    Resource::allClientsAndObserversRemoved();
}

void FontResource::checkNotify()
{
    m_fontLoadShortLimitTimer.stop();
    m_fontLoadLongLimitTimer.stop();

    Resource::checkNotify();
}

} // namespace blink