Introduce page / block / inline levels

2 files changed, 23 insertions, 4 deletions

diff --git a/src/util/eco_string.rs b/src/util/eco_string.rs
index f1dfdfaf..ab8d5642 100644
--- a/src/util/eco_string.rs
+++ b/src/util/eco_string.rs
@@ -5,6 +5,8 @@ use std::hash::{Hash, Hasher};
 use std::ops::Deref;
 use std::rc::Rc;
 
+use super::RcExt;
+
 /// An economical string with inline storage and clone-on-write semantics.
 #[derive(Clone)]
 pub struct EcoString(Repr);
@@ -293,10 +295,7 @@ impl From<EcoString> for String {
     fn from(s: EcoString) -> Self {
         match s.0 {
             Repr::Small { .. } => s.as_str().to_owned(),
-            Repr::Large(rc) => match Rc::try_unwrap(rc) {
-                Ok(string) => string,
-                Err(rc) => (*rc).clone(),
-            },
+            Repr::Large(rc) => Rc::take(rc),
         }
     }
 }
diff --git a/src/util/mod.rs b/src/util/mod.rs
index 05dc9025..c4272c55 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -10,6 +10,7 @@ use std::cell::RefMut;
 use std::cmp::Ordering;
 use std::ops::Range;
 use std::path::{Component, Path, PathBuf};
+use std::rc::Rc;
 
 /// Additional methods for booleans.
 pub trait BoolExt {
@@ -67,6 +68,25 @@ impl<T> OptionExt<T> for Option<T> {
     }
 }
 
+/// Additional methods for reference-counted pointers.
+pub trait RcExt<T> {
+    /// Takes the inner value if there is exactly one strong reference and
+    /// clones it otherwise.
+    fn take(self) -> T;
+}
+
+impl<T> RcExt<T> for Rc<T>
+where
+    T: Clone,
+{
+    fn take(self) -> T {
+        match Rc::try_unwrap(self) {
+            Ok(v) => v,
+            Err(rc) => (*rc).clone(),
+        }
+    }
+}
+
 /// Additional methods for slices.
 pub trait SliceExt<T> {
     /// Split a slice into consecutive groups with the same key.