Auto merge of #46 - pcwalton:postscript-names, r=glennw

Support serialization of `CGFont` objects.

Due to API limitations, this will only serialize native fonts, not Web
fonts. Specifically, there is no way I know of to fetch the
`CGDataProvider` associated with a `CGFont`. This isn't a problem for
Servo, however, because Servo knows which fonts are Web fonts and stores
their byte data separately.

r? @glennw or @larsbergstrom

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Cargo.toml

@@ -10,3 +10,5 @@ license = "MIT / Apache-2.0"
 [dependencies]
 libc = "0.2"
 core-foundation = "0.2"
+serde = "0.6"
+

src/font.rs

@@ -8,9 +8,12 @@
 // except according to those terms.
 
 use core_foundation::base::{CFRelease, CFRetain, CFTypeID, CFTypeRef, TCFType};
+use core_foundation::string::{CFString, CFStringRef};
 use data_provider::{CGDataProvider, CGDataProviderRef};
 
 use libc;
+use serde::de::{self, Deserialize, Deserializer};
+use serde::ser::{Serialize, Serializer};
 use std::mem;
 use std::ptr;
 
@@ -28,6 +31,22 @@ pub struct CGFont {
 unsafe impl Send for CGFont {}
 unsafe impl Sync for CGFont {}
 
+impl Serialize for CGFont {
+    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error> where S: Serializer {
+        let postscript_name = self.postscript_name().to_string();
+        postscript_name.serialize(serializer)
+    }
+}
+
+impl Deserialize for CGFont {
+    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error> where D: Deserializer {
+        let postscript_name: String = try!(Deserialize::deserialize(deserializer));
+        CGFont::from_name(&CFString::new(&*postscript_name)).map_err(|err| {
+            de::Error::syntax("Couldn't find a font with that PostScript name!")
+        })
+    }
+}
+
 impl Clone for CGFont {
     #[inline]
     fn clone(&self) -> CGFont {
@@ -92,15 +111,35 @@ impl CGFont {
             }
         }
     }
+
+    pub fn from_name(name: &CFString) -> Result<CGFont, ()> {
+        unsafe {
+            let font_ref = CGFontCreateWithFontName(name.as_concrete_TypeRef());
+            if font_ref != ptr::null() {
+                Ok(TCFType::wrap_under_create_rule(font_ref))
+            } else {
+                Err(())
+            }
+        }
+    }
+
+    pub fn postscript_name(&self) -> CFString {
+        unsafe {
+            let string_ref = CGFontCopyPostScriptName(self.obj);
+            TCFType::wrap_under_create_rule(string_ref)
+        }
+    }
 }
 
 #[link(name = "ApplicationServices", kind = "framework")]
 extern {
-
-    // TODO: basically nothing has bindings (even commented-out)  besides what we use.
+    // TODO: basically nothing has bindings (even commented-out) besides what we use.
     fn CGFontCreateWithDataProvider(provider: CGDataProviderRef) -> CGFontRef;
+    fn CGFontCreateWithFontName(name: CFStringRef) -> CGFontRef;
     fn CGFontGetTypeID() -> CFTypeID;
 
+    fn CGFontCopyPostScriptName(font: CGFontRef) -> CFStringRef;
+
     // These do the same thing as CFRetain/CFRelease, except
     // gracefully handle a NULL argument. We don't use them.
     //fn CGFontRetain(font: CGFontRef);

src/lib.rs

@@ -9,6 +9,7 @@
 
 extern crate libc;
 extern crate core_foundation;
+extern crate serde;
 
 pub mod base;
 pub mod color_space;