Add dynamic web font support to Chrome's port of Webkit. ...

third_party/WebKit/WebCore/platform/graphics/chromium/FontCustomPlatformData.cpp

Index: third_party/WebKit/WebCore/platform/graphics/chromium/FontCustomPlatformData.cpp
===================================================================
--- third_party/WebKit/WebCore/platform/graphics/chromium/FontCustomPlatformData.cpp	(revision 7512)
+++ third_party/WebKit/WebCore/platform/graphics/chromium/FontCustomPlatformData.cpp	(working copy)
@@ -21,34 +21,205 @@
 #include "config.h"
 #include "FontCustomPlatformData.h"
 
-#include "SharedBuffer.h"
+#if PLATFORM(WIN_OS)
+#include "Base64.h"
+#include "ChromiumBridge.h"
+#include "OpenTypeUtilities.h"
+#endif
+
 #include "FontPlatformData.h"
 #include "NotImplemented.h"
+#include "SharedBuffer.h"
 
+#if PLATFORM(WIN_OS)
+#include <objbase.h>
+#include <t2embapi.h>
+#pragma comment(lib, "t2embed")
+#endif
+
 namespace WebCore {
 
 FontCustomPlatformData::~FontCustomPlatformData()
 {
-    // FIXME: Release the HFONT ref?
+#if PLATFORM(WIN_OS)
+    if (m_fontReference) {
+        if (m_name.isNull()) {
+            ULONG status;
+            TTDeleteEmbeddedFont(m_fontReference, 0, &status);
+        } else
+            RemoveFontMemResourceEx(m_fontReference);
+    }
+#endif
 }
 
-FontPlatformData FontCustomPlatformData::fontPlatformData(int size, bool bold, bool italic)
+FontPlatformData FontCustomPlatformData::fontPlatformData(int size,
+                                                          bool bold,
+                                                          bool italic,
+                                                          FontRenderingMode mode)
 {
-    return FontPlatformData(m_font, size);
+#if PLATFORM(WIN_OS)
+    ASSERT(m_fontReference);
+
+    LOGFONT logFont;
+    if (m_name.isNull())
+        TTGetNewFontName(&m_fontReference, logFont.lfFaceName,
+                         LF_FACESIZE, 0, 0);
+    else {
+        // 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() >= LF_FACESIZE) {

[eroman, 2009/01/06 02:17:05]

I think this check should be against m_name.length() + 1, since it must also
accomodate the null-terminator.

+            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 = ChromiumBridge::layoutTestMode() ?
+                        NONANTIALIASED_QUALITY :
+                        DEFAULT_QUALITY; // Honor user's desktop settings.
+    logFont.lfPitchAndFamily = DEFAULT_PITCH | FF_DONTCARE;
+    logFont.lfItalic = italic;
+    logFont.lfWeight = bold ? 700 : 400;
+
+    HFONT hfont = CreateFontIndirect(&logFont);
+    return FontPlatformData(hfont, size);
+#else
+    notImplemented();
+    return FontPlatformData();
+#endif
 }
 
+#if PLATFORM(WIN_OS)
+// FIXME: EOTStream class and static functions in this #if block are
+// duplicated from platform/graphics/win/FontCustomplatformData.cpp
+// and need to be shared.
+
+// Streams the concatenation of a header and font data.
+class EOTStream {
+public:
+    EOTStream(const Vector<UInt8, 512>& eotHeader, const SharedBuffer* fontData, size_t overlayDst, size_t overlaySrc, size_t overlayLength)
+        : m_eotHeader(eotHeader)
+        , m_fontData(fontData)
+        , m_overlayDst(overlayDst)
+        , m_overlaySrc(overlaySrc)
+        , m_overlayLength(overlayLength)
+        , m_offset(0)
+        , m_inHeader(true)
+    {
+    }
+
+    size_t read(void* buffer, size_t count);
+
+private:
+    const Vector<UInt8, 512>& m_eotHeader;
+    const SharedBuffer* m_fontData;
+    size_t m_overlayDst;
+    size_t m_overlaySrc;
+    size_t m_overlayLength;
+    size_t m_offset;
+    bool m_inHeader;
+};
+
+size_t EOTStream::read(void* buffer, size_t count)
+{
+    size_t bytesToRead = count;
+    if (m_inHeader) {
+        size_t bytesFromHeader = std::min(m_eotHeader.size() - m_offset, count);
+        memcpy(buffer, m_eotHeader.data() + m_offset, bytesFromHeader);
+        m_offset += bytesFromHeader;
+        bytesToRead -= bytesFromHeader;
+        if (m_offset == m_eotHeader.size()) {
+            m_inHeader = false;
+            m_offset = 0;
+        }
+    }
+    if (bytesToRead && !m_inHeader) {
+        size_t bytesFromData = std::min(m_fontData->size() - m_offset, bytesToRead);
+        memcpy(buffer, m_fontData->data() + m_offset, bytesFromData);
+        if (m_offset < m_overlayDst + m_overlayLength && m_offset + bytesFromData >= m_overlayDst) {
+            size_t dstOffset = std::max<int>(m_overlayDst - m_offset, 0);
+            size_t srcOffset = std::max<int>(0, m_offset - m_overlayDst);
+            size_t bytesToCopy = std::min(bytesFromData - dstOffset, m_overlayLength - srcOffset);
+            memcpy(reinterpret_cast<char*>(buffer) + dstOffset, m_fontData->data() + m_overlaySrc + srcOffset, bytesToCopy);
+        }
+        m_offset += bytesFromData;
+        bytesToRead -= bytesFromData;
+    }
+    return count - bytesToRead;
+}
+
+static unsigned long WINAPIV readEmbedProc(void* stream, void* buffer, unsigned long length)
+{
+    return static_cast<EOTStream*>(stream)->read(buffer, length);
+}
+
+// Creates a unique and unpredictable font name, in order to avoid collisions and to
+// not allow access from CSS.
+static String createUniqueFontName()
+{
+    Vector<char> fontUuid(sizeof(GUID));
+    CoCreateGuid(reinterpret_cast<GUID*>(fontUuid.data()));
+
+    Vector<char> fontNameVector;
+    base64Encode(fontUuid, fontNameVector);
+    ASSERT(fontNameVector.size() < LF_FACESIZE);
+    return String(fontNameVector.data(), fontNameVector.size());
+}
+#endif
+
 FontCustomPlatformData* createFontCustomPlatformData(SharedBuffer* buffer)
 {
     ASSERT_ARG(buffer, buffer);
 
 #if PLATFORM(WIN_OS)
-    HFONT font = 0;
-    // FIXME: Figure out some way to get Windows to give us back a font object.
-    if (!font)
+    // Introduce the font to GDI. AddFontMemResourceEx cannot be used, 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). TTLoadEmbeddedFont lets us override the font family name, so using a unique name
+    // we avoid namespace collisions.
+
+    String fontName = createUniqueFontName();
+
+    // TTLoadEmbeddedFont works only with Embedded OpenType (.eot) data,
+    // so we need to create an EOT header and prepend it to the font data.
+    Vector<UInt8, 512> eotHeader;
+    size_t overlayDst;
+    size_t overlaySrc;
+    size_t overlayLength;
+
+    if (!getEOTHeader(buffer, eotHeader, overlayDst, overlaySrc, overlayLength))
         return 0;
-    return new FontCustomPlatformData(font);
+
+    HANDLE fontReference;
+    ULONG privStatus;
+    ULONG status;
+    EOTStream eotStream(eotHeader, buffer, overlayDst, overlaySrc, overlayLength);
+
+    LONG loadEmbeddedFontResult = TTLoadEmbeddedFont(&fontReference, TTLOAD_PRIVATE, &privStatus, LICENSE_PREVIEWPRINT, &status, readEmbedProc, &eotStream, const_cast<LPWSTR>(fontName.charactersWithNullTermination()), 0, 0);
+    if (loadEmbeddedFontResult == E_NONE)
+        fontName = String();
+    else {
+        fontReference = renameAndActivateFont(buffer, fontName);
+        if (!fontReference) {
+            return 0;
+        }
+    }
+
+    return new FontCustomPlatformData(fontReference, fontName);
 #else
-    notImplemented();
+    notImplemented();;
+    return 0;
 #endif
 }