[librsvg: 5/14] rsvg_node_chars_append(): Don't copy the string; assume it comes validated from libxml2

[Federico Mena Quintero <federico src gnome org>]

commit 073fffdb81a9d133b9a37f9fcf689cdd31f9ba0d
Author: Federico Mena Quintero <federico gnome org>
Date:   Wed Jan 24 11:13:52 2018 -0600

    rsvg_node_chars_append(): Don't copy the string; assume it comes validated from libxml2

 rust/src/chars.rs | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)
---
diff --git a/rust/src/chars.rs b/rust/src/chars.rs
index ef0dcb8..d94d48b 100644
--- a/rust/src/chars.rs
+++ b/rust/src/chars.rs
@@ -1,6 +1,7 @@
 use libc;
 use std;
 use std::cell::RefCell;
+use std::str;
 
 use drawing_ctx::{self, RsvgDrawingCtx};
 use handle::RsvgHandle;
@@ -85,16 +86,13 @@ pub extern fn rsvg_node_chars_append(raw_node: *const RsvgNode,
     assert!(!text.is_null());
     assert!(len >= 0);
 
-    // We don't use from_glib to convert the text here, since we are
-    // not sure that it actually is valid UTF-8.  We can't use CStr
-    // because we are not getting passed nul-terminated data.  We'll
-    // do this by hand instead.
-
+    // libxml2 already validated the incoming string as UTF-8.  Note that
+    // it is *not* nul-terminated; this is why we create a byte slice first.
     let bytes = unsafe { std::slice::from_raw_parts(text as *const u8, len as usize) };
-    let utf8 = String::from_utf8_lossy(bytes);
+    let utf8 = unsafe { str::from_utf8_unchecked(bytes) };
 
     node.with_impl(|chars: &NodeChars| {
-        chars.append(&utf8);
+        chars.append(utf8);
     });
 }