glyphpagetreenode.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
 * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
 *
 * 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. 
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "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 OR ITS 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 "config.h"
#include "GlyphPageTreeNode.h"

#include "CharacterNames.h"
#include "SegmentedFontData.h"
#include "SimpleFontData.h"
#include <wtf/unicode/Unicode.h>

namespace WebCore {

using std::max;
using std::min;

HashMap<int, GlyphPageTreeNode*>* GlyphPageTreeNode::roots = 0;
GlyphPageTreeNode* GlyphPageTreeNode::pageZeroRoot = 0;

GlyphPageTreeNode* GlyphPageTreeNode::getRoot(unsigned pageNumber)
{
    static bool initialized;
    if (!initialized) {
        initialized = true;
        roots = new HashMap<int, GlyphPageTreeNode*>;
        pageZeroRoot = new GlyphPageTreeNode;
    }

    GlyphPageTreeNode* node = pageNumber ? roots->get(pageNumber) : pageZeroRoot;
    if (!node) {
        node = new GlyphPageTreeNode;
#ifndef NDEBUG
        node->m_pageNumber = pageNumber;
#endif
        if (pageNumber)
            roots->set(pageNumber, node);
        else
            pageZeroRoot = node;
    }
    return node;
}

size_t GlyphPageTreeNode::treeGlyphPageCount()
{
    size_t count = 0;
    if (roots) {
        HashMap<int, GlyphPageTreeNode*>::iterator end = roots->end();
        for (HashMap<int, GlyphPageTreeNode*>::iterator it = roots->begin(); it != end; ++it)
            count += it->second->pageCount();
    }
    
    if (pageZeroRoot)
        count += pageZeroRoot->pageCount();

    return count;
}

size_t GlyphPageTreeNode::pageCount() const
{
    size_t count = m_page && m_page->owner() == this ? 1 : 0;
    HashMap<const FontData*, GlyphPageTreeNode*>::const_iterator end = m_children.end();
    for (HashMap<const FontData*, GlyphPageTreeNode*>::const_iterator it = m_children.begin(); it != end; ++it)
        count += it->second->pageCount();

    return count;
}

void GlyphPageTreeNode::pruneTreeCustomFontData(const FontData* fontData)
{
    // Enumerate all the roots and prune any tree that contains our custom font data.
    if (roots) {
        HashMap<int, GlyphPageTreeNode*>::iterator end = roots->end();
        for (HashMap<int, GlyphPageTreeNode*>::iterator it = roots->begin(); it != end; ++it)
            it->second->pruneCustomFontData(fontData);
    }
    
    if (pageZeroRoot)
        pageZeroRoot->pruneCustomFontData(fontData);
}

void GlyphPageTreeNode::pruneTreeFontData(const SimpleFontData* fontData)
{
    if (roots) {
        HashMap<int, GlyphPageTreeNode*>::iterator end = roots->end();
        for (HashMap<int, GlyphPageTreeNode*>::iterator it = roots->begin(); it != end; ++it)
            it->second->pruneFontData(fontData);
    }
    
    if (pageZeroRoot)
        pageZeroRoot->pruneFontData(fontData);
}

GlyphPageTreeNode::~GlyphPageTreeNode()
{
    deleteAllValues(m_children);
    delete m_systemFallbackChild;
}

void GlyphPageTreeNode::initializePage(const FontData* fontData, unsigned pageNumber)
{
    ASSERT(!m_page);

    // This function must not be called for the root of the tree, because that
    // level does not contain any glyphs.
    ASSERT(m_level > 0 && m_parent);

    // The parent's page will be 0 if we are level one or the parent's font data
    // did not contain any glyphs for that page.
    GlyphPage* parentPage = m_parent->page();

    // NULL FontData means we're being asked for the system fallback font.
    if (fontData) {
        if (m_level == 1) {
            // Children of the root hold pure pages. These will cover only one
            // font data's glyphs, and will have glyph index 0 if the font data does not
            // contain the glyph.
            unsigned start = pageNumber * GlyphPage::size;
            UChar buffer[GlyphPage::size * 2 + 2];
            unsigned bufferLength;
            unsigned i;

            // Fill in a buffer with the entire "page" of characters that we want to look up glyphs for.
            if (start < 0x10000) {
                bufferLength = GlyphPage::size;
                for (i = 0; i < GlyphPage::size; i++)
                    buffer[i] = start + i;

                if (start == 0) {
                    // Control characters must not render at all.
                    for (i = 0; i < 0x20; ++i)
                        buffer[i] = zeroWidthSpace;
                    for (i = 0x7F; i < 0xA0; i++)
                        buffer[i] = zeroWidthSpace;

                    // \n, \t, and nonbreaking space must render as a space.
                    buffer[(int)'\n'] = ' ';
                    buffer[(int)'\t'] = ' ';
                    buffer[noBreakSpace] = ' ';
                } else if (start == (leftToRightMark & ~(GlyphPage::size - 1))) {
                    // LRM, RLM, LRE, RLE and PDF must not render at all.
                    buffer[leftToRightMark - start] = zeroWidthSpace;
                    buffer[rightToLeftMark - start] = zeroWidthSpace;
                    buffer[leftToRightEmbed - start] = zeroWidthSpace;
                    buffer[rightToLeftEmbed - start] = zeroWidthSpace;
                    buffer[leftToRightOverride - start] = zeroWidthSpace;
                    buffer[rightToLeftOverride - start] = zeroWidthSpace;
                    buffer[popDirectionalFormatting - start] = zeroWidthSpace;
                } else if (start == (objectReplacementCharacter & ~(GlyphPage::size - 1))) {
                    // Object replacement character must not render at all.
                    buffer[objectReplacementCharacter - start] = zeroWidthSpace;
                }
            } else {
                bufferLength = GlyphPage::size * 2;
                for (i = 0; i < GlyphPage::size; i++) {
                    int c = i + start;
                    buffer[i * 2] = U16_LEAD(c);
                    buffer[i * 2 + 1] = U16_TRAIL(c);
                }
            }
            
            m_page = GlyphPage::create(this);

            // Now that we have a buffer full of characters, we want to get back an array
            // of glyph indices.  This part involves calling into the platform-specific 
            // routine of our glyph map for actually filling in the page with the glyphs.
            // Success is not guaranteed. For example, Times fails to fill page 260, giving glyph data
            // for only 128 out of 256 characters.
            bool haveGlyphs;