Source/WebCore/platform/graphics/skia/FontCustomPlatformData.cpp

/*
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#include "config.h"
#include "FontCustomPlatformData.h"

#if OS(WINDOWS)
#include "OpenTypeUtilities.h"
#elif OS(UNIX)
#include "SkStream.h"
#endif

#include "FontPlatformData.h"
#include "LayoutTestSupport.h"
#include "NotImplemented.h"
#include "OpenTypeSanitizer.h"
#include "SharedBuffer.h"

#if OS(WINDOWS)
#include <objbase.h>
#include <wtf/text/Base64.h>
#elif OS(UNIX)
#include <cstring>
#endif

namespace WebCore {

FontCustomPlatformData::~FontCustomPlatformData()
{
#if OS(WINDOWS)
    if (m_fontReference)
        RemoveFontMemResourceEx(m_fontReference);
#elif OS(UNIX)
    if (m_fontReference)
        m_fontReference->unref();
#endif
}

FontPlatformData FontCustomPlatformData::fontPlatformData(int size, bool bold, bool italic, FontOrientation orientation,
                                                          FontWidthVariant, FontRenderingMode mode)
{
#if OS(WINDOWS)
    ASSERT(m_fontReference);

    LOGFONT logFont;
    // m_name comes from createUniqueFontName, which, in turn, gets
    // it from base64-encoded uuid (128-bit). So, m_name
    // can never be longer than LF_FACESIZE (32).
    if (m_name.length() + 1 >= LF_FACESIZE) {
        ASSERT_NOT_REACHED();
        return FontPlatformData();
    }
    memcpy(logFont.lfFaceName, m_name.charactersWithNullTermination(),
           sizeof(logFont.lfFaceName[0]) * (1 + m_name.length()));

    // FIXME: almost identical to FillLogFont in FontCacheWin.cpp.
    // Need to refactor.
    logFont.lfHeight = -size;
    logFont.lfWidth = 0;
    logFont.lfEscapement = 0;
    logFont.lfOrientation = 0;
    logFont.lfUnderline = false;
    logFont.lfStrikeOut = false;
    logFont.lfCharSet = DEFAULT_CHARSET;
    logFont.lfOutPrecision = OUT_TT_ONLY_PRECIS;
    logFont.lfQuality = isRunningLayoutTest() ?
                        NONANTIALIASED_QUALITY :
                        DEFAULT_QUALITY; // Honor user's desktop settings.
    logFont.lfPitchAndFamily = DEFAULT_PITCH | FF_DONTCARE;
    logFont.lfItalic = italic;
    logFont.lfWeight = bold ? FW_BOLD : FW_DONTCARE;

    HFONT hfont = CreateFontIndirect(&logFont);
    return FontPlatformData(hfont, size, orientation);
#elif OS(UNIX)
    ASSERT(m_fontReference);
    return FontPlatformData(m_fontReference, "", size, bold && !m_fontReference->isBold(), italic && !m_fontReference->isItalic(), orientation);
#else
    notImplemented();
    return FontPlatformData();
#endif
}

#if OS(WINDOWS)
// Creates a unique and unpredictable font name, in order to avoid collisions and to
// not allow access from CSS.
static String createUniqueFontName()
{
    GUID fontUuid;
    CoCreateGuid(&fontUuid);

    String fontName = base64Encode(reinterpret_cast<char*>(&fontUuid), sizeof(fontUuid));
    ASSERT(fontName.length() < LF_FACESIZE);
    return fontName;
}
#endif

#if OS(UNIX)
class RemoteFontStream : public SkStream {
public:
    explicit RemoteFontStream(PassRefPtr<SharedBuffer> buffer)
        : m_buffer(buffer)
        , m_offset(0)
    {
    }

    virtual ~RemoteFontStream()
    {
    }

    virtual bool rewind()
    {
        m_offset = 0;
        return true;
    }

    virtual size_t read(void* buffer, size_t size)
    {
        if (!buffer && !size) {
            // This is request for the length of the stream.
            return m_buffer->size();
        }
        // This is a request to read bytes or skip bytes (when buffer is 0).
        if (!m_buffer->data() || !m_buffer->size())
            return 0;
        size_t left = m_buffer->size() - m_offset;
        size_t bytesToConsume = std::min(left, size);
        if (buffer)
            std::memcpy(buffer, m_buffer->data() + m_offset, bytesToConsume);
        m_offset += bytesToConsume;
        return bytesToConsume;
    }

private:
    RefPtr<SharedBuffer> m_buffer;
    size_t m_offset;
};
#endif

FontCustomPlatformData* createFontCustomPlatformData(SharedBuffer* buffer)
{
    ASSERT_ARG(buffer, buffer);

#if USE(OPENTYPE_SANITIZER)
    OpenTypeSanitizer sanitizer(buffer);
    RefPtr<SharedBuffer> transcodeBuffer = sanitizer.sanitize();
    if (!transcodeBuffer)
        return 0; // validation failed.
    buffer = transcodeBuffer.get();
#endif

#if OS(WINDOWS)
    // Introduce the font to GDI. AddFontMemResourceEx should be used with care, because it will pollute the process's
    // font namespace (Windows has no API for creating an HFONT from data without exposing the font to the
    // entire process first).
    String fontName = createUniqueFontName();
    HANDLE fontReference = renameAndActivateFont(buffer, fontName);
    if (!fontReference)
        return 0;
    return new FontCustomPlatformData(fontReference, fontName);
#elif OS(UNIX)
    RemoteFontStream* stream = new RemoteFontStream(buffer);
    SkTypeface* typeface = SkTypeface::CreateFromStream(stream);
    stream->unref();
    if (!typeface)
        return 0;
    return new FontCustomPlatformData(typeface);
#else
    notImplemented();
    return 0;
#endif
}

bool FontCustomPlatformData::supportsFormat(const String& format)
{
    return equalIgnoringCase(format, "truetype") || equalIgnoringCase(format, "opentype")
#if USE(OPENTYPE_SANITIZER)
        || equalIgnoringCase(format, "woff")
#endif
    ;
}

}