servo: Merge #7443 - Implement get_table_for_tag on FreeType (from mbrubeck:get_table); r=pcwalton

Updates freetype to pick up servo/rust-freetype#37

r? @glennw

Source-Repo: https://github.com/servo/servo
Source-Revision: 0ad284766b3f12097dce1e5858b5d07e870478eb

servo/components/gfx/font.rs

@@ -42,7 +42,7 @@ pub trait FontHandleMethods: Sized {
     fn glyph_h_advance(&self, GlyphId) -> Option<FractionalPixel>;
     fn glyph_h_kerning(&self, GlyphId, GlyphId) -> FractionalPixel;
     fn metrics(&self) -> FontMetrics;
-    fn get_table_for_tag(&self, FontTableTag) -> Option<FontTable>;
+    fn get_table_for_tag(&self, FontTableTag) -> Option<Box<FontTable>>;
 }
 
 // Used to abstract over the shaper's choice of fixed int representation.
@@ -170,7 +170,7 @@ impl Font {
         self.shaper.as_ref().unwrap()
     }
 
-    pub fn get_table_for_tag(&self, tag: FontTableTag) -> Option<FontTable> {
+    pub fn get_table_for_tag(&self, tag: FontTableTag) -> Option<Box<FontTable>> {
         let result = self.handle.get_table_for_tag(tag);
         let status = if result.is_some() { "Found" } else { "Didn't find" };
 

servo/components/gfx/lib.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #![feature(arc_weak)]
-#![cfg_attr(any(target_os = "linux", target_os = "android"), feature(box_raw))]
+#![feature(box_raw)]
 #![feature(box_syntax)]
 #![feature(custom_attribute)]
 #![feature(custom_derive)]

servo/components/gfx/platform/freetype/font.rs

@@ -16,7 +16,7 @@ use util::str::c_str_to_string;
 
 use freetype::freetype::{FTErrorMethods, FT_F26Dot6, FT_Face, FT_FaceRec};
 use freetype::freetype::{FT_Get_Char_Index, FT_Get_Postscript_Name};
-use freetype::freetype::{FT_Get_Kerning, FT_Get_Sfnt_Table};
+use freetype::freetype::{FT_Get_Kerning, FT_Get_Sfnt_Table, FT_Load_Sfnt_Table};
 use freetype::freetype::{FT_GlyphSlot, FT_Library, FT_Long, FT_ULong};
 use freetype::freetype::{FT_KERNING_DEFAULT, FT_STYLE_FLAG_ITALIC, FT_STYLE_FLAG_BOLD};
 use freetype::freetype::{FT_Load_Glyph, FT_Set_Char_Size};
@@ -38,11 +38,13 @@ fn fixed_to_float_ft(f: i32) -> f64 {
     fixed_to_float(6, f)
 }
 
-pub struct FontTable;
+pub struct FontTable {
+    buffer: Vec<u8>,
+}
 
 impl FontTableMethods for FontTable {
-    fn with_buffer<F>(&self, _blk: F) where F: FnOnce(*const u8, usize) {
-        panic!()
+    fn with_buffer<F>(&self, blk: F) where F: FnOnce(*const u8, usize) {
+        blk(self.buffer.as_ptr(), self.buffer.len())
     }
 }
 
@@ -261,8 +263,22 @@ impl FontHandleMethods for FontHandle {
         return metrics;
     }
 
-    fn get_table_for_tag(&self, _: FontTableTag) -> Option<FontTable> {
-        None
+    fn get_table_for_tag(&self, tag: FontTableTag) -> Option<Box<FontTable>> {
+        let tag = tag as FT_ULong;
+
+        unsafe {
+            // Get the length
+            let mut len = 0;
+            if !FT_Load_Sfnt_Table(self.face, tag, 0, ptr::null_mut(), &mut len).succeeded() {
+                return None
+            }
+            // Get the bytes
+            let mut buf = vec![0u8; len as usize];
+            if !FT_Load_Sfnt_Table(self.face, tag, 0, buf.as_mut_ptr(), &mut len).succeeded() {
+                return None
+            }
+            Some(box FontTable { buffer: buf })
+        }
     }
 }
 

servo/components/gfx/platform/macos/font.rs

@@ -192,10 +192,10 @@ impl FontHandleMethods for FontHandle {
         return metrics;
     }
 
-    fn get_table_for_tag(&self, tag: FontTableTag) -> Option<FontTable> {
+    fn get_table_for_tag(&self, tag: FontTableTag) -> Option<Box<FontTable>> {
         let result: Option<CFData> = self.ctfont.get_font_table(tag);
         result.and_then(|data| {
-            Some(FontTable::wrap(data))
+            Some(box FontTable::wrap(data))
         })
     }
 }

servo/components/gfx/text/shaping/harfbuzz.rs

@@ -41,7 +41,6 @@ use harfbuzz::{hb_position_t, hb_tag_t};
 use libc::{c_uint, c_int, c_void, c_char};
 use std::char;
 use std::cmp;
-use std::mem;
 use std::ptr;
 use util::geometry::Au;
 use util::range::Range;
@@ -616,16 +615,19 @@ extern fn get_font_table_func(_: *mut hb_face_t,
         // TODO(Issue #197): reuse font table data, which will change the unsound trickery here.
         match (*(*font_and_shaping_options).font).get_table_for_tag(tag as FontTableTag) {
             None => ptr::null_mut(),
-            Some(ref font_table) => {
-                let skinny_font_table_ptr: *const FontTable = font_table;   // private context
+            Some(font_table) => {
+                // `Box::into_raw` intentionally leaks the FontTable so we don't destroy the buffer
+                // while HarfBuzz is using it.  When HarfBuzz is done with the buffer, it will pass
+                // this raw pointer back to `destroy_blob_func` which will deallocate the Box.
+                let font_table_ptr = Box::into_raw(font_table);
 
                 let mut blob: *mut hb_blob_t = ptr::null_mut();
-                (*skinny_font_table_ptr).with_buffer(|buf: *const u8, len: usize| {
+                (*font_table_ptr).with_buffer(|buf: *const u8, len: usize| {
                     // HarfBuzz calls `destroy_blob_func` when the buffer is no longer needed.
                     blob = RUST_hb_blob_create(buf as *const c_char,
                                                len as c_uint,
                                                HB_MEMORY_MODE_READONLY,
-                                               mem::transmute(skinny_font_table_ptr),
+                                               font_table_ptr as *mut c_void,
                                                destroy_blob_func);
                 });
 
@@ -636,10 +638,8 @@ extern fn get_font_table_func(_: *mut hb_face_t,
     }
 }
 
-// TODO(Issue #197): reuse font table data, which will change the unsound trickery here.
-// In particular, we'll need to cast to a boxed, rather than owned, FontTable.
-
-// even better, should cache the harfbuzz blobs directly instead of recreating a lot.
-extern fn destroy_blob_func(_: *mut c_void) {
-    // TODO: Previous code here was broken. Rewrite.
+extern fn destroy_blob_func(font_table_ptr: *mut c_void) {
+    unsafe {
+        drop(Box::from_raw(font_table_ptr as *mut FontTable));
+    }
 }

servo/components/servo/Cargo.lock

@@ -497,7 +497,7 @@ dependencies = [
 [[package]]
 name = "freetype"
 version = "0.1.0"
-source = "git+https://github.com/servo/rust-freetype#507cee774458dc704c902d405bb869fb286f7a64"
+source = "git+https://github.com/servo/rust-freetype#d564ff90a3c69d987f5c015d7ec034cfaee21aff"
 dependencies = [
  "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

servo/ports/cef/Cargo.lock

@@ -489,7 +489,7 @@ dependencies = [
 [[package]]
 name = "freetype"
 version = "0.1.0"
-source = "git+https://github.com/servo/rust-freetype#507cee774458dc704c902d405bb869fb286f7a64"
+source = "git+https://github.com/servo/rust-freetype#d564ff90a3c69d987f5c015d7ec034cfaee21aff"
 dependencies = [
  "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]

servo/ports/gonk/Cargo.lock

@@ -444,7 +444,7 @@ dependencies = [
 [[package]]
 name = "freetype"
 version = "0.1.0"
-source = "git+https://github.com/servo/rust-freetype#507cee774458dc704c902d405bb869fb286f7a64"
+source = "git+https://github.com/servo/rust-freetype#d564ff90a3c69d987f5c015d7ec034cfaee21aff"
 dependencies = [
  "libc 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]