/*
 * Copyright (C) 2008 Alp Toker <alp@atoker.com>
 * Copyright (C) 2010 Igalia S.L.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#include "config.h"
#include "FontCustomPlatformData.h"

#include "FontPlatformData.h"
#include "SharedBuffer.h"
#include <cairo-ft.h>
#include <cairo.h>

namespace WebCore {

static void releaseCustomFontData(void* data)
{
    static_cast<SharedBuffer*>(data)->deref();
}

FontCustomPlatformData::FontCustomPlatformData(FT_Face freeTypeFace, SharedBuffer& buffer)
    : m_fontFace(cairo_ft_font_face_create_for_ft_face(freeTypeFace, FT_LOAD_FORCE_AUTOHINT))
{
    // FT_LOAD_FORCE_AUTOHINT prohibits use of the font's native hinting. This
    // is a safe option for custom fonts because (a) some such fonts may have
    // broken hinting, which site admins may not notice if other browsers do not
    // use the native hints, and (b) allowing native hints exposes the FreeType
    // bytecode interpreter to potentially-malicious input. Treating web fonts
    // differently than system fonts is non-ideal, but the result of autohinting
    // is always decent, whereas native hints sometimes look terrible, and
    // unlike system fonts where Fontconfig may change the hinting settings on a
    // per-font basis, the same settings are used for all web fonts. Note that
    // Chrome is considering switching from autohinting to native hinting in
    // https://code.google.com/p/chromium/issues/detail?id=173207 but this is
    // more risk than we want to assume for now. See
    // https://bugs.webkit.org/show_bug.cgi?id=140994 before changing this.

    buffer.ref(); // This is balanced by the buffer->deref() in releaseCustomFontData.
    static cairo_user_data_key_t bufferKey;
    cairo_font_face_set_user_data(m_fontFace, &bufferKey, &buffer,
         static_cast<cairo_destroy_func_t>(releaseCustomFontData));

    // Cairo doesn't do FreeType reference counting, so we need to ensure that when
    // this cairo_font_face_t is destroyed, it cleans up the FreeType face as well.
    static cairo_user_data_key_t freeTypeFaceKey;
    cairo_font_face_set_user_data(m_fontFace, &freeTypeFaceKey, freeTypeFace,
         reinterpret_cast<cairo_destroy_func_t>(FT_Done_Face));
}

FontCustomPlatformData::~FontCustomPlatformData()
{
    cairo_font_face_destroy(m_fontFace);
}

FontPlatformData FontCustomPlatformData::fontPlatformData(const FontDescription& description, bool bold, bool italic)
{
    return FontPlatformData(m_fontFace, description, bold, italic);
}

std::unique_ptr<FontCustomPlatformData> createFontCustomPlatformData(SharedBuffer& buffer)
{
    static FT_Library library;
    if (!library && FT_Init_FreeType(&library)) {
        library = nullptr;
        return nullptr;
    }

    FT_Face freeTypeFace;
    if (FT_New_Memory_Face(library, reinterpret_cast<const FT_Byte*>(buffer.data()), buffer.size(), 0, &freeTypeFace))
        return nullptr;
    return std::make_unique<FontCustomPlatformData>(freeTypeFace, buffer);
}

bool FontCustomPlatformData::supportsFormat(const String& format)
{
    return equalLettersIgnoringASCIICase(format, "truetype")
        || equalLettersIgnoringASCIICase(format, "opentype")
#if USE(WOFF2)
        || equalLettersIgnoringASCIICase(format, "woff2")
#endif
        || equalLettersIgnoringASCIICase(format, "woff");
}

}