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      1 /*
      2  * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *
      8  * 1.  Redistributions of source code must retain the above copyright
      9  *     notice, this list of conditions and the following disclaimer.
     10  * 2.  Redistributions in binary form must reproduce the above copyright
     11  *     notice, this list of conditions and the following disclaimer in the
     12  *     documentation and/or other materials provided with the distribution.
     13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
     14  *     its contributors may be used to endorse or promote products derived
     15  *     from this software without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
     18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include "config.h"
     30 #include "GlyphPageTreeNode.h"
     31 
     32 #include "PlatformString.h"
     33 #include "SegmentedFontData.h"
     34 #include "SimpleFontData.h"
     35 #include <stdio.h>
     36 #include <wtf/text/CString.h>
     37 #include <wtf/unicode/CharacterNames.h>
     38 #include <wtf/unicode/Unicode.h>
     39 
     40 namespace WebCore {
     41 
     42 using std::max;
     43 using std::min;
     44 
     45 HashMap<int, GlyphPageTreeNode*>* GlyphPageTreeNode::roots = 0;
     46 GlyphPageTreeNode* GlyphPageTreeNode::pageZeroRoot = 0;
     47 
     48 GlyphPageTreeNode* GlyphPageTreeNode::getRoot(unsigned pageNumber)
     49 {
     50     static bool initialized;
     51     if (!initialized) {
     52         initialized = true;
     53         roots = new HashMap<int, GlyphPageTreeNode*>;
     54         pageZeroRoot = new GlyphPageTreeNode;
     55     }
     56 
     57     GlyphPageTreeNode* node = pageNumber ? roots->get(pageNumber) : pageZeroRoot;
     58     if (!node) {
     59         node = new GlyphPageTreeNode;
     60 #ifndef NDEBUG
     61         node->m_pageNumber = pageNumber;
     62 #endif
     63         if (pageNumber)
     64             roots->set(pageNumber, node);
     65         else
     66             pageZeroRoot = node;
     67     }
     68     return node;
     69 }
     70 
     71 size_t GlyphPageTreeNode::treeGlyphPageCount()
     72 {
     73     size_t count = 0;
     74     if (roots) {
     75         HashMap<int, GlyphPageTreeNode*>::iterator end = roots->end();
     76         for (HashMap<int, GlyphPageTreeNode*>::iterator it = roots->begin(); it != end; ++it)
     77             count += it->second->pageCount();
     78     }
     79 
     80     if (pageZeroRoot)
     81         count += pageZeroRoot->pageCount();
     82 
     83     return count;
     84 }
     85 
     86 size_t GlyphPageTreeNode::pageCount() const
     87 {
     88     size_t count = m_page && m_page->owner() == this ? 1 : 0;
     89     HashMap<const FontData*, GlyphPageTreeNode*>::const_iterator end = m_children.end();
     90     for (HashMap<const FontData*, GlyphPageTreeNode*>::const_iterator it = m_children.begin(); it != end; ++it)
     91         count += it->second->pageCount();
     92 
     93     return count;
     94 }
     95 
     96 void GlyphPageTreeNode::pruneTreeCustomFontData(const FontData* fontData)
     97 {
     98     // Enumerate all the roots and prune any tree that contains our custom font data.
     99     if (roots) {
    100         HashMap<int, GlyphPageTreeNode*>::iterator end = roots->end();
    101         for (HashMap<int, GlyphPageTreeNode*>::iterator it = roots->begin(); it != end; ++it)
    102             it->second->pruneCustomFontData(fontData);
    103     }
    104 
    105     if (pageZeroRoot)
    106         pageZeroRoot->pruneCustomFontData(fontData);
    107 }
    108 
    109 void GlyphPageTreeNode::pruneTreeFontData(const SimpleFontData* fontData)
    110 {
    111     if (roots) {
    112         HashMap<int, GlyphPageTreeNode*>::iterator end = roots->end();
    113         for (HashMap<int, GlyphPageTreeNode*>::iterator it = roots->begin(); it != end; ++it)
    114             it->second->pruneFontData(fontData);
    115     }
    116 
    117     if (pageZeroRoot)
    118         pageZeroRoot->pruneFontData(fontData);
    119 }
    120 
    121 GlyphPageTreeNode::~GlyphPageTreeNode()
    122 {
    123     deleteAllValues(m_children);
    124     delete m_systemFallbackChild;
    125 }
    126 
    127 static bool fill(GlyphPage* pageToFill, unsigned offset, unsigned length, UChar* buffer, unsigned bufferLength, const SimpleFontData* fontData)
    128 {
    129     if (!fontData->isSVGFont())
    130         return pageToFill->fill(offset, length, buffer, bufferLength, fontData);
    131 
    132     // SVG Fonts do not use the glyph page cache. Zero fill the glyph
    133     // positions and return false to indicate the glyphs were not found.
    134     for (unsigned i = 0; i < length; ++i)
    135         pageToFill->setGlyphDataForIndex(offset + i, 0, 0);
    136     return false;
    137 }
    138 
    139 void GlyphPageTreeNode::initializePage(const FontData* fontData, unsigned pageNumber)
    140 {
    141     ASSERT(!m_page);
    142 
    143     // This function must not be called for the root of the tree, because that
    144     // level does not contain any glyphs.
    145     ASSERT(m_level > 0 && m_parent);
    146 
    147     // The parent's page will be 0 if we are level one or the parent's font data
    148     // did not contain any glyphs for that page.
    149     GlyphPage* parentPage = m_parent->page();
    150 
    151     // NULL FontData means we're being asked for the system fallback font.
    152     if (fontData) {
    153         if (m_level == 1) {
    154             // Children of the root hold pure pages. These will cover only one
    155             // font data's glyphs, and will have glyph index 0 if the font data does not
    156             // contain the glyph.
    157             unsigned start = pageNumber * GlyphPage::size;
    158             UChar buffer[GlyphPage::size * 2 + 2];
    159             unsigned bufferLength;
    160             unsigned i;
    161 
    162             // Fill in a buffer with the entire "page" of characters that we want to look up glyphs for.
    163             if (start < 0x10000) {
    164                 bufferLength = GlyphPage::size;
    165                 for (i = 0; i < GlyphPage::size; i++)
    166                     buffer[i] = start + i;
    167 
    168                 if (start == 0) {
    169                     // Control characters must not render at all.
    170                     for (i = 0; i < 0x20; ++i)
    171                         buffer[i] = zeroWidthSpace;
    172                     for (i = 0x7F; i < 0xA0; i++)
    173                         buffer[i] = zeroWidthSpace;
    174                     buffer[softHyphen] = zeroWidthSpace;
    175 
    176                     // \n, \t, and nonbreaking space must render as a space.
    177                     buffer[(int)'\n'] = ' ';
    178                     buffer[(int)'\t'] = ' ';
    179                     buffer[noBreakSpace] = ' ';
    180                 } else if (start == (leftToRightMark & ~(GlyphPage::size - 1))) {
    181                     // LRM, RLM, LRE, RLE, ZWNJ, ZWJ, and PDF must not render at all.
    182                     buffer[leftToRightMark - start] = zeroWidthSpace;
    183                     buffer[rightToLeftMark - start] = zeroWidthSpace;
    184                     buffer[leftToRightEmbed - start] = zeroWidthSpace;
    185                     buffer[rightToLeftEmbed - start] = zeroWidthSpace;
    186                     buffer[leftToRightOverride - start] = zeroWidthSpace;
    187                     buffer[rightToLeftOverride - start] = zeroWidthSpace;
    188                     buffer[zeroWidthNonJoiner - start] = zeroWidthSpace;
    189                     buffer[zeroWidthJoiner - start] = zeroWidthSpace;
    190                     buffer[popDirectionalFormatting - start] = zeroWidthSpace;
    191                 } else if (start == (objectReplacementCharacter & ~(GlyphPage::size - 1))) {
    192                     // Object replacement character must not render at all.
    193                     buffer[objectReplacementCharacter - start] = zeroWidthSpace;
    194                 } else if (start == (zeroWidthNoBreakSpace & ~(GlyphPage::size - 1))) {
    195                     // ZWNBS/BOM must not render at all.
    196                     buffer[zeroWidthNoBreakSpace - start] = zeroWidthSpace;
    197                 }
    198             } else {
    199                 bufferLength = GlyphPage::size * 2;
    200                 for (i = 0; i < GlyphPage::size; i++) {
    201                     int c = i + start;
    202                     buffer[i * 2] = U16_LEAD(c);
    203                     buffer[i * 2 + 1] = U16_TRAIL(c);
    204                 }
    205             }
    206 
    207             m_page = GlyphPage::create(this);
    208 
    209             // Now that we have a buffer full of characters, we want to get back an array
    210             // of glyph indices.  This part involves calling into the platform-specific
    211             // routine of our glyph map for actually filling in the page with the glyphs.
    212             // Success is not guaranteed. For example, Times fails to fill page 260, giving glyph data
    213             // for only 128 out of 256 characters.
    214             bool haveGlyphs;
    215             if (fontData->isSegmented()) {
    216                 haveGlyphs = false;
    217 
    218                 const SegmentedFontData* segmentedFontData = static_cast<const SegmentedFontData*>(fontData);
    219                 unsigned numRanges = segmentedFontData->numRanges();
    220                 bool zeroFilled = false;
    221                 RefPtr<GlyphPage> scratchPage;
    222                 GlyphPage* pageToFill = m_page.get();
    223                 for (unsigned i = 0; i < numRanges; i++) {
    224                     const FontDataRange& range = segmentedFontData->rangeAt(i);
    225                     // all this casting is to ensure all the parameters to min and max have the same type,
    226                     // to avoid ambiguous template parameter errors on Windows
    227                     int from = max(0, static_cast<int>(range.from()) - static_cast<int>(start));
    228                     int to = 1 + min(static_cast<int>(range.to()) - static_cast<int>(start), static_cast<int>(GlyphPage::size) - 1);
    229                     if (from < static_cast<int>(GlyphPage::size) && to > 0) {
    230                         if (haveGlyphs && !scratchPage) {
    231                             scratchPage = GlyphPage::create(this);
    232                             pageToFill = scratchPage.get();
    233                         }
    234 
    235                         if (!zeroFilled) {
    236                             if (from > 0 || to < static_cast<int>(GlyphPage::size)) {
    237                                 for (unsigned i = 0; i < GlyphPage::size; i++)
    238                                     pageToFill->setGlyphDataForIndex(i, 0, 0);
    239                             }
    240                             zeroFilled = true;
    241                         }
    242                         haveGlyphs |= fill(pageToFill, from, to - from, buffer + from * (start < 0x10000 ? 1 : 2), (to - from) * (start < 0x10000 ? 1 : 2), range.fontData());
    243                         if (scratchPage) {
    244                             ASSERT(to <=  static_cast<int>(GlyphPage::size));
    245                             for (int j = from; j < to; j++) {
    246                                 if (!m_page->glyphAt(j) && pageToFill->glyphAt(j))
    247                                     m_page->setGlyphDataForIndex(j, pageToFill->glyphDataForIndex(j));
    248                             }
    249                         }
    250                     }
    251                 }
    252             } else
    253                 haveGlyphs = fill(m_page.get(), 0, GlyphPage::size, buffer, bufferLength, static_cast<const SimpleFontData*>(fontData));
    254 
    255             if (!haveGlyphs)
    256                 m_page = 0;
    257         } else if (parentPage && parentPage->owner() != m_parent) {
    258             // The page we're overriding may not be owned by our parent node.
    259             // This happens when our parent node provides no useful overrides
    260             // and just copies the pointer to an already-existing page (see
    261             // below).
    262             //
    263             // We want our override to be shared by all nodes that reference
    264             // that page to avoid duplication, and so standardize on having the
    265             // page's owner collect all the overrides.  Call getChild on the
    266             // page owner with the desired font data (this will populate
    267             // the page) and then reference it.
    268             m_page = parentPage->owner()->getChild(fontData, pageNumber)->page();
    269         } else {
    270             // Get the pure page for the fallback font (at level 1 with no
    271             // overrides). getRootChild will always create a page if one
    272             // doesn't exist, but the page doesn't necessarily have glyphs
    273             // (this pointer may be 0).
    274             GlyphPage* fallbackPage = getRootChild(fontData, pageNumber)->page();
    275             if (!parentPage) {
    276                 // When the parent has no glyphs for this page, we can easily
    277                 // override it just by supplying the glyphs from our font.
    278                 m_page = fallbackPage;
    279             } else if (!fallbackPage) {
    280                 // When our font has no glyphs for this page, we can just reference the
    281                 // parent page.
    282                 m_page = parentPage;
    283             } else {
    284                 // Combine the parent's glyphs and ours to form a new more complete page.
    285                 m_page = GlyphPage::create(this);
    286 
    287                 // Overlay the parent page on the fallback page. Check if the fallback font
    288                 // has added anything.
    289                 bool newGlyphs = false;
    290                 for (unsigned i = 0; i < GlyphPage::size; i++) {
    291                     if (parentPage->glyphAt(i))
    292                         m_page->setGlyphDataForIndex(i, parentPage->glyphDataForIndex(i));
    293                     else  if (fallbackPage->glyphAt(i)) {
    294                         m_page->setGlyphDataForIndex(i, fallbackPage->glyphDataForIndex(i));
    295                         newGlyphs = true;
    296                     } else
    297                         m_page->setGlyphDataForIndex(i, 0, 0);
    298                 }
    299 
    300                 if (!newGlyphs)
    301                     // We didn't override anything, so our override is just the parent page.
    302                     m_page = parentPage;
    303             }
    304         }
    305     } else {
    306         m_page = GlyphPage::create(this);
    307         // System fallback. Initialized with the parent's page here, as individual
    308         // entries may use different fonts depending on character. If the Font
    309         // ever finds it needs a glyph out of the system fallback page, it will
    310         // ask the system for the best font to use and fill that glyph in for us.
    311         if (parentPage)
    312             m_page->copyFrom(*parentPage);
    313         else
    314             m_page->clear();
    315     }
    316 }
    317 
    318 GlyphPageTreeNode* GlyphPageTreeNode::getChild(const FontData* fontData, unsigned pageNumber)
    319 {
    320     ASSERT(fontData || !m_isSystemFallback);
    321     ASSERT(pageNumber == m_pageNumber);
    322 
    323     GlyphPageTreeNode* child = fontData ? m_children.get(fontData) : m_systemFallbackChild;
    324     if (!child) {
    325         child = new GlyphPageTreeNode;
    326         child->m_parent = this;
    327         child->m_level = m_level + 1;
    328         if (fontData && fontData->isCustomFont()) {
    329             for (GlyphPageTreeNode* curr = this; curr; curr = curr->m_parent)
    330                 curr->m_customFontCount++;
    331         }
    332 
    333 #ifndef NDEBUG
    334         child->m_pageNumber = m_pageNumber;
    335 #endif
    336         if (fontData) {
    337             m_children.set(fontData, child);
    338             fontData->setMaxGlyphPageTreeLevel(max(fontData->maxGlyphPageTreeLevel(), child->m_level));
    339         } else {
    340             m_systemFallbackChild = child;
    341             child->m_isSystemFallback = true;
    342         }
    343         child->initializePage(fontData, pageNumber);
    344     }
    345     return child;
    346 }
    347 
    348 void GlyphPageTreeNode::pruneCustomFontData(const FontData* fontData)
    349 {
    350     if (!fontData || !m_customFontCount)
    351         return;
    352 
    353     // Prune any branch that contains this FontData.
    354     GlyphPageTreeNode* node = m_children.get(fontData);
    355     if (node) {
    356         m_children.remove(fontData);
    357         unsigned fontCount = node->m_customFontCount + 1;
    358         delete node;
    359         for (GlyphPageTreeNode* curr = this; curr; curr = curr->m_parent)
    360             curr->m_customFontCount -= fontCount;
    361     }
    362 
    363     // Check any branches that remain that still have custom fonts underneath them.
    364     if (!m_customFontCount)
    365         return;
    366     HashMap<const FontData*, GlyphPageTreeNode*>::iterator end = m_children.end();
    367     for (HashMap<const FontData*, GlyphPageTreeNode*>::iterator it = m_children.begin(); it != end; ++it)
    368         it->second->pruneCustomFontData(fontData);
    369 }
    370 
    371 void GlyphPageTreeNode::pruneFontData(const SimpleFontData* fontData, unsigned level)
    372 {
    373     ASSERT(fontData);
    374     if (!fontData)
    375         return;
    376 
    377     // Prune any branch that contains this FontData.
    378     HashMap<const FontData*, GlyphPageTreeNode*>::iterator child = m_children.find(fontData);
    379     if (child == m_children.end()) {
    380         // If there is no level-1 node for fontData, then there is no deeper node for it in this tree.
    381         if (!level)
    382             return;
    383     } else {
    384         GlyphPageTreeNode* node = child->second;
    385         m_children.remove(fontData);
    386         unsigned customFontCount = node->m_customFontCount;
    387         delete node;
    388         if (customFontCount) {
    389             for (GlyphPageTreeNode* curr = this; curr; curr = curr->m_parent)
    390                 curr->m_customFontCount -= customFontCount;
    391         }
    392     }
    393 
    394     level++;
    395     if (level > fontData->maxGlyphPageTreeLevel())
    396         return;
    397 
    398     HashMap<const FontData*, GlyphPageTreeNode*>::iterator end = m_children.end();
    399     for (HashMap<const FontData*, GlyphPageTreeNode*>::iterator it = m_children.begin(); it != end; ++it)
    400         it->second->pruneFontData(fontData, level);
    401 }
    402 
    403 #ifndef NDEBUG
    404     void GlyphPageTreeNode::showSubtree()
    405     {
    406         Vector<char> indent(level());
    407         indent.fill('\t', level());
    408         indent.append(0);
    409 
    410         HashMap<const FontData*, GlyphPageTreeNode*>::iterator end = m_children.end();
    411         for (HashMap<const FontData*, GlyphPageTreeNode*>::iterator it = m_children.begin(); it != end; ++it) {
    412             printf("%s\t%p %s\n", indent.data(), it->first, it->first->description().utf8().data());
    413             it->second->showSubtree();
    414         }
    415         if (m_systemFallbackChild) {
    416             printf("%s\t* fallback\n", indent.data());
    417             m_systemFallbackChild->showSubtree();
    418         }
    419     }
    420 #endif
    421 
    422 }
    423 
    424 #ifndef NDEBUG
    425 void showGlyphPageTrees()
    426 {
    427     printf("Page 0:\n");
    428     showGlyphPageTree(0);
    429     HashMap<int, WebCore::GlyphPageTreeNode*>::iterator end = WebCore::GlyphPageTreeNode::roots->end();
    430     for (HashMap<int, WebCore::GlyphPageTreeNode*>::iterator it = WebCore::GlyphPageTreeNode::roots->begin(); it != end; ++it) {
    431         printf("\nPage %d:\n", it->first);
    432         showGlyphPageTree(it->first);
    433     }
    434 }
    435 
    436 void showGlyphPageTree(unsigned pageNumber)
    437 {
    438     WebCore::GlyphPageTreeNode::getRoot(pageNumber)->showSubtree();
    439 }
    440 #endif
    441