From 851617d48856a9063b42e491288df12553f63cfa Mon Sep 17 00:00:00 2001
From: Gareth Daniel Smith <garethdanielsmith@gmail.com>
Date: Thu, 4 Oct 2012 20:22:53 +0100
Subject: [PATCH 1/2] Add an &str.to_managed method to allow creating
 non-constant @str values (for issue #3433).

---
 src/libcore/str.rs | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/libcore/str.rs b/src/libcore/str.rs
index cf996a8b254ca..55105d8aa2812 100644
--- a/src/libcore/str.rs
+++ b/src/libcore/str.rs
@@ -1869,6 +1869,11 @@ pub pure fn escape_unicode(s: &str) -> ~str {
     move out
 }
 
+extern mod rustrt {
+    #[rust_stack]
+    pure fn upcall_str_new_shared(cstr: *libc::c_char, len: size_t) -> @str;
+}
+
 /// Unsafe operations
 pub mod raw {
 
@@ -2087,6 +2092,7 @@ pub trait StrSlice {
     fn escape_default() -> ~str;
     fn escape_unicode() -> ~str;
     pure fn to_unique() -> ~str;
+    pure fn to_managed() -> @str;
     pure fn char_at(i: uint) -> char;
 }
 
@@ -2198,6 +2204,14 @@ impl &str: StrSlice {
     #[inline]
     pure fn to_unique() -> ~str { self.slice(0, self.len()) }
 
+    #[inline]
+    pure fn to_managed() -> @str {
+        do str::as_buf(self) |p, _len| {
+            rustrt::upcall_str_new_shared(p as *libc::c_char,
+                                          self.len() as size_t)
+        }
+    }
+
     #[inline]
     pure fn char_at(i: uint) -> char { char_at(self, i) }
 }
@@ -3175,4 +3189,10 @@ mod tests {
         assert escape_default(~"\U0001d4ea\r") == ~"\\U0001d4ea\\r";
     }
 
+    #[test]
+    fn test_to_managed() {
+        assert (~"abc").to_managed() == @"abc";
+        assert view("abcdef", 1, 5).to_managed() == @"bcde";
+    }
+
 }

From 6f690a1c96c370d3598b9e45836f95d503087989 Mon Sep 17 00:00:00 2001
From: Gareth Daniel Smith <garethdanielsmith@gmail.com>
Date: Sat, 6 Oct 2012 11:11:06 +0100
Subject: [PATCH 2/2] Implement to_managed without using an upcall function, as
 suggested by brson.

---
 src/libcore/str.rs | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)

diff --git a/src/libcore/str.rs b/src/libcore/str.rs
index 55105d8aa2812..fb62fc65b6d1e 100644
--- a/src/libcore/str.rs
+++ b/src/libcore/str.rs
@@ -1869,11 +1869,6 @@ pub pure fn escape_unicode(s: &str) -> ~str {
     move out
 }
 
-extern mod rustrt {
-    #[rust_stack]
-    pure fn upcall_str_new_shared(cstr: *libc::c_char, len: size_t) -> @str;
-}
-
 /// Unsafe operations
 pub mod raw {
 
@@ -2206,10 +2201,10 @@ impl &str: StrSlice {
 
     #[inline]
     pure fn to_managed() -> @str {
-        do str::as_buf(self) |p, _len| {
-            rustrt::upcall_str_new_shared(p as *libc::c_char,
-                                          self.len() as size_t)
-        }
+        let v = at_vec::from_fn(self.len() + 1, |i| {
+            if i == self.len() { 0 } else { self[i] }
+        });
+        unsafe { ::cast::transmute(v) }
     }
 
     #[inline]