Revert of Remove Mac native font type members from FontPlatformData

Source/platform/fonts/mac/MemoryActivatedFont.mm

+/*
+ * This file is part of the internal font implementation.
+ *
+ * Copyright (c) 2010 Google Inc. All rights reserved.
+ *
+ * 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.
+ *
+ */
+
+// This file provides additional functionality to the Mac FontPlatformData class
+// defined in WebCore/platform/mac/FontPlatformDataMac.mm.
+// Because we want to support loading fonts between processes in the face of
+// font loading being blocked by the sandbox, we need a mechnasim to both
+// do the loading of in-memory fonts and keep track of them.
+
+#import "config.h"
+#import "platform/fonts/mac/MemoryActivatedFont.h"
+
+#import <AppKit/NSFont.h>
+#import "platform/LinkHash.h"
+#import "platform/fonts/FontPlatformData.h"
+#import "public/platform/mac/WebSandboxSupport.h"
+#import "public/platform/Platform.h"
+#import "wtf/HashMap.h"
+
+namespace blink {
+
+namespace {
+
+typedef HashMap<uint32_t, MemoryActivatedFont*> FontContainerRefMemoryFontHash;
+typedef HashMap<WTF::String, MemoryActivatedFont*> FontNameMemoryFontHash;
+
+// Caching:
+//
+// Requesting a font from the browser process is expensive and so is
+// "activating" said font.  Caching of loaded fonts is complicated by the fact
+// that it's impossible to get a unique identifier for the on-disk font file
+// from inside the sandboxed renderer process.
+// This means that when loading a font we need to round-trip through the browser
+// process in order to get the unique font file identifer which we might already
+// have activated and cached.
+//
+// In order to save as much work as we can, we maintain 2 levels of caching
+// for the font data:
+// 1. A dumb cache keyed by the font name/style (information we can determine
+// from inside the sandbox).
+// 2. A smarter cache keyed by the real "unique font id".
+//
+// In order to perform a lookup in #2 we need to consult with the browser to get
+// us the lookup key.  While this doesn't save us the font load, it does save
+// us font activation.
+//
+// It's important to remember that existing FontPlatformData objects are already
+// cached, so a cache miss in the code in this file isn't necessarily so bad.
+
+FontContainerRefMemoryFontHash& fontCacheByFontID()
+{
+    DEFINE_STATIC_LOCAL(FontContainerRefMemoryFontHash, srcFontIDCache, ());
+    return srcFontIDCache;
+}
+
+
+FontNameMemoryFontHash& fontCacheByFontName()
+{
+    DEFINE_STATIC_LOCAL(FontNameMemoryFontHash, srcFontNameCache, ());
+    return srcFontNameCache;
+}
+
+// Given a font specified by |srcFont|, use the information we can query in
+// the sandbox to construct a key which we hope will be as unique as possible
+// to the containing font file.
+WTF::String hashKeyFromNSFont(NSFont* srcFont)
+{
+    NSFontDescriptor* desc = [srcFont fontDescriptor];
+    NSFontSymbolicTraits traits = [desc symbolicTraits];
+    return WTF::String::format("%s %x", [[srcFont fontName] UTF8String], traits);
+}
+
+// The only way we can tell that an in-process font has failed to load
+// is if CTFontCopyGraphicsFont() returns the LastResort font.
+bool isLastResortFont(CGFontRef cgFont)
+{
+    NSString* fontName = (NSString*)CGFontCopyPostScriptName(cgFont);
+    return [fontName isEqualToString:@"LastResort"];
+}
+
+// Given an in-process font which has failed to load, return a
+// MemoryActivatedFont* corresponding to an in-memory representation of the
+// same font loaded from the browser process.
+// On failure this function returns a PassRefPtr pointing to 0.
+PassRefPtr<MemoryActivatedFont> loadFontFromBrowserProcess(NSFont* nsFont)
+{
+    // First try to lookup in our cache with the limited information we have.
+    WTF::String hashKey = hashKeyFromNSFont(nsFont);
+    RefPtr<MemoryActivatedFont> font(fontCacheByFontName().get(hashKey));
+    if (font)
+        return font;
+
+    CGFontRef tmpCGFont;
+    uint32_t fontID;
+    // Send cross-process request to load font.
+    blink::WebSandboxSupport* sandboxSupport = blink::Platform::current()->sandboxSupport();
+    if (!sandboxSupport) {
+        // This function should only be called in response to an error loading a
+        // font due to being blocked by the sandbox.
+        // This by definition shouldn't happen if there is no sandbox support.
+        ASSERT_NOT_REACHED();
+        return nullptr;
+    }
+    if (!sandboxSupport->loadFont(nsFont, &tmpCGFont, &fontID))
+        return nullptr;
+
+    RetainPtr<CGFontRef> cgFont(tmpCGFont);
+    // Now that we have the fontID from the browser process, we can consult
+    // the ID cache.
+    font = fontCacheByFontID().get(fontID);
+    if (font)
+        // FIXME: WebSandboxSupport::loadFont() should consult the id cache
+        // before activating the font.
+        return font;
+
+    return MemoryActivatedFont::create(fontID, nsFont, cgFont.get());
+}
+
+} // namespace
+
+PassRefPtr<MemoryActivatedFont> MemoryActivatedFont::create(uint32_t fontID, NSFont* nsFont, CGFontRef cgFont)
+{
+  return adoptRef(new MemoryActivatedFont(fontID, nsFont, cgFont));
+}
+
+MemoryActivatedFont::MemoryActivatedFont(uint32_t fontID, NSFont* nsFont, CGFontRef cgFont)
+    : m_cgFont(cgFont)
+    , m_fontID(fontID)
+    , m_inSandboxHashKey(hashKeyFromNSFont(nsFont))
+{
+    // Add ourselves to caches.
+    fontCacheByFontID().add(fontID, this);
+    fontCacheByFontName().add(m_inSandboxHashKey, this);
+}
+
+// Destructor - Unload font container from memory and remove ourselves
+// from cache.
+MemoryActivatedFont::~MemoryActivatedFont()
+{
+    // First remove ourselves from the caches.
+    ASSERT(fontCacheByFontID().contains(m_fontID));
+    ASSERT(fontCacheByFontName().contains(m_inSandboxHashKey));
+
+    fontCacheByFontID().remove(m_fontID);
+    fontCacheByFontName().remove(m_inSandboxHashKey);
+}
+
+// Given an NSFont, try to load a representation of that font into the cgFont
+// parameter.  If loading is blocked by the sandbox, the font may be loaded
+// cross-process.
+// If sandbox loading also fails, a fallback font is loaded.
+//
+// Considerations:
+// * cgFont must be CFRelease()ed by the caller when done.
+//
+// Parameters:
+// * nsFont - The font we wish to load.
+// * fontSize - point size of the font we wish to load.
+// * outNSFont - The font that was actually loaded or null if loading failed.
+// * cgFont - on output this contains the CGFontRef corresponding to the NSFont
+//   that was picked in the end.  The caller is responsible for calling
+//   CFRelease() on this parameter when done with it.
+// * fontID - on output, the ID corresponding to nsFont.
+void FontPlatformData::loadFont(NSFont* nsFont, float fontSize, NSFont*& outNSFont, CGFontRef& cgFont)
+{
+    outNSFont = nsFont;
+    cgFont = CTFontCopyGraphicsFont(toCTFontRef(outNSFont), 0);
+    if (outNSFont && cgFont && isLastResortFont(cgFont)) {
+        // Release old CGFontRef since it points at the LastResort font which we don't want.
+        CFRelease(cgFont);
+        cgFont = 0;
+
+        // Font loading was blocked by the Sandbox.
+        m_inMemoryFont = loadFontFromBrowserProcess(outNSFont);
+        if (m_inMemoryFont) {
+            cgFont = m_inMemoryFont->cgFont();
+
+            // Need to add an extra retain so output semantics of this function
+            // are consistent.
+            CFRetain(cgFont);
+        } else {
+            // If we still can't load the font, set |outNSFont| to null so that FontPlatformData won't be used.
+            outNSFont = 0;
+        }
+    }
+}
+
+} // namespace blink