auto merge of #14115 : alexcrichton/rust/core-fmt, r=brson

This was a more difficult change than I thought it would be, and it is unfortunately a breaking change rather than a drop-in replacement. Most of the rationale can be found in the third commit.

cc #13851

src/compiletest/common.rs

@@ -41,15 +41,15 @@ impl FromStr for Mode {
 impl fmt::Show for Mode {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         let msg = match *self {
-          CompileFail => "compile-fail",
-          RunFail => "run-fail",
-          RunPass => "run-pass",
-          Pretty => "pretty",
-          DebugInfoGdb => "debuginfo-gdb",
-          DebugInfoLldb => "debuginfo-lldb",
-          Codegen => "codegen",
+            CompileFail => "compile-fail",
+            RunFail => "run-fail",
+            RunPass => "run-pass",
+            Pretty => "pretty",
+            DebugInfoGdb => "debuginfo-gdb",
+            DebugInfoLldb => "debuginfo-lldb",
+            Codegen => "codegen",
         };
-        write!(f.buf, "{}", msg)
+        msg.fmt(f)
     }
 }
 

src/libcollections/btree.rs

@@ -425,8 +425,8 @@ impl<K: fmt::Show + TotalOrd, V: fmt::Show> fmt::Show for Leaf<K, V> {
     ///Returns a string representation of a Leaf.
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         for (i, s) in self.elts.iter().enumerate() {
-            if i != 0 { try!(write!(f.buf, " // ")) }
-            try!(write!(f.buf, "{}", *s))
+            if i != 0 { try!(write!(f, " // ")) }
+            try!(write!(f, "{}", *s))
         }
         Ok(())
     }
@@ -654,10 +654,10 @@ impl<K: fmt::Show + TotalOrd, V: fmt::Show> fmt::Show for Branch<K, V> {
     ///Returns a string representation of a Branch.
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         for (i, s) in self.elts.iter().enumerate() {
-            if i != 0 { try!(write!(f.buf, " // ")) }
-            try!(write!(f.buf, "{}", *s))
+            if i != 0 { try!(write!(f, " // ")) }
+            try!(write!(f, "{}", *s))
         }
-        write!(f.buf, " // rightmost child: ({}) ", *self.rightmost_child)
+        write!(f, " // rightmost child: ({}) ", *self.rightmost_child)
     }
 }
 
@@ -715,7 +715,7 @@ impl<K: TotalOrd, V: TotalEq> TotalOrd for LeafElt<K, V> {
 impl<K: fmt::Show + TotalOrd, V: fmt::Show> fmt::Show for LeafElt<K, V> {
     ///Returns a string representation of a LeafElt.
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f.buf, "Key: {}, value: {};", self.key, self.value)
+        write!(f, "Key: {}, value: {};", self.key, self.value)
     }
 }
 
@@ -765,7 +765,7 @@ impl<K: fmt::Show + TotalOrd, V: fmt::Show> fmt::Show for BranchElt<K, V> {
     /// Returns string containing key, value, and child (which should recur to a
     /// leaf) Consider changing in future to be more readable.
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f.buf, "Key: {}, value: {}, (child: {})",
+        write!(f, "Key: {}, value: {}, (child: {})",
                self.key, self.value, *self.left)
     }
 }

src/libcollections/hashmap.rs

@@ -1418,14 +1418,14 @@ impl<K: TotalEq + Hash<S>, V: Eq, S, H: Hasher<S>> Eq for HashMap<K, V, H> {
 
 impl<K: TotalEq + Hash<S> + Show, V: Show, S, H: Hasher<S>> Show for HashMap<K, V, H> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        try!(write!(f.buf, r"\{"));
+        try!(write!(f, r"\{"));
 
         for (i, (k, v)) in self.iter().enumerate() {
-            if i != 0 { try!(write!(f.buf, ", ")); }
-            try!(write!(f.buf, "{}: {}", *k, *v));
+            if i != 0 { try!(write!(f, ", ")); }
+            try!(write!(f, "{}: {}", *k, *v));
         }
 
-        write!(f.buf, r"\}")
+        write!(f, r"\}")
     }
 }
 
@@ -1605,14 +1605,14 @@ impl<T: TotalEq + Hash<S>, S, H: Hasher<S>> HashSet<T, H> {
 
 impl<T: TotalEq + Hash<S> + fmt::Show, S, H: Hasher<S>> fmt::Show for HashSet<T, H> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        try!(write!(f.buf, r"\{"));
+        try!(write!(f, r"\{"));
 
         for (i, x) in self.iter().enumerate() {
-            if i != 0 { try!(write!(f.buf, ", ")); }
-            try!(write!(f.buf, "{}", *x));
+            if i != 0 { try!(write!(f, ", ")); }
+            try!(write!(f, "{}", *x));
         }
 
-        write!(f.buf, r"\}")
+        write!(f, r"\}")
     }
 }
 

src/libcollections/lru_cache.rs

@@ -205,20 +205,20 @@ impl<A: fmt::Show + Hash + TotalEq, B: fmt::Show> fmt::Show for LruCache<A, B> {
     /// Return a string that lists the key-value pairs from most-recently
     /// used to least-recently used.
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        try!(write!(f.buf, r"\{"));
+        try!(write!(f, r"\{"));
         let mut cur = self.head;
         for i in range(0, self.len()) {
-            if i > 0 { try!(write!(f.buf, ", ")) }
+            if i > 0 { try!(write!(f, ", ")) }
             unsafe {
                 cur = (*cur).next;
-                try!(write!(f.buf, "{}", (*cur).key));
+                try!(write!(f, "{}", (*cur).key));
             }
-            try!(write!(f.buf, ": "));
+            try!(write!(f, ": "));
             unsafe {
-                try!(write!(f.buf, "{}", (*cur).value));
+                try!(write!(f, "{}", (*cur).value));
             }
         }
-        write!(f.buf, r"\}")
+        write!(f, r"\}")
     }
 }
 

src/libcore/any.rs

@@ -166,12 +166,12 @@ mod tests {
 
         match a.as_ref::<uint>() {
             Some(&5) => {}
-            x => fail!("Unexpected value {:?}", x)
+            x => fail!("Unexpected value {}", x)
         }
 
         match a.as_ref::<Test>() {
             None => {}
-            x => fail!("Unexpected value {:?}", x)
+            x => fail!("Unexpected value {}", x)
         }
     }
 
@@ -189,35 +189,35 @@ mod tests {
                 assert_eq!(*x, 5u);
                 *x = 612;
             }
-            x => fail!("Unexpected value {:?}", x)
+            x => fail!("Unexpected value {}", x)
         }
 
         match b_r.as_mut::<uint>() {
             Some(x) => {
                 assert_eq!(*x, 7u);
                 *x = 413;
             }
-            x => fail!("Unexpected value {:?}", x)
+            x => fail!("Unexpected value {}", x)
         }
 
         match a_r.as_mut::<Test>() {
             None => (),
-            x => fail!("Unexpected value {:?}", x)
+            x => fail!("Unexpected value {}", x)
         }
 
         match b_r.as_mut::<Test>() {
             None => (),
-            x => fail!("Unexpected value {:?}", x)
+            x => fail!("Unexpected value {}", x)
         }
 
         match a_r.as_mut::<uint>() {
             Some(&612) => {}
-            x => fail!("Unexpected value {:?}", x)
+            x => fail!("Unexpected value {}", x)
         }
 
         match b_r.as_mut::<uint>() {
             Some(&413) => {}
-            x => fail!("Unexpected value {:?}", x)
+            x => fail!("Unexpected value {}", x)
         }
     }
 
@@ -229,11 +229,11 @@ mod tests {
         let b = box Test as Box<Any>;
 
         match a.move::<uint>() {
-            Ok(a) => { assert_eq!(a, box 8u); }
+            Ok(a) => { assert!(a == box 8u); }
             Err(..) => fail!()
         }
         match b.move::<Test>() {
-            Ok(a) => { assert_eq!(a, box Test); }
+            Ok(a) => { assert!(a == box Test); }
             Err(..) => fail!()
         }
 
@@ -246,13 +246,14 @@ mod tests {
 
     #[test]
     fn test_show() {
-        let a = box 8u as Box<::realcore::any::Any>;
-        let b = box Test as Box<::realcore::any::Any>;
-        assert_eq!(format!("{}", a), "Box<Any>".to_owned());
-        assert_eq!(format!("{}", b), "Box<Any>".to_owned());
-
-        let a = &8u as &::realcore::any::Any;
-        let b = &Test as &::realcore::any::Any;
+        use realstd::to_str::ToStr;
+        let a = box 8u as Box<::realstd::any::Any>;
+        let b = box Test as Box<::realstd::any::Any>;
+        assert_eq!(a.to_str(), "Box<Any>".to_owned());
+        assert_eq!(b.to_str(), "Box<Any>".to_owned());
+
+        let a = &8u as &Any;
+        let b = &Test as &Any;
         assert_eq!(format!("{}", a), "&Any".to_owned());
         assert_eq!(format!("{}", b), "&Any".to_owned());
     }

src/libcore/cell.rs

@@ -255,7 +255,7 @@ mod test {
     fn cell_has_sensible_show() {
         use str::StrSlice;
 
-        let x = ::realcore::cell::Cell::new("foo bar");
+        let x = Cell::new("foo bar");
         assert!(format!("{}", x).contains(x.get()));
 
         x.set("baz qux");

src/libcore/char.rs

@@ -633,9 +633,9 @@ impl Default for char {
 mod test {
     use super::{escape_unicode, escape_default};
 
-    use realcore::char::Char;
+    use char::Char;
     use slice::ImmutableVector;
-    use realstd::option::{Some, None};
+    use option::{Some, None};
     use realstd::strbuf::StrBuf;
     use realstd::str::StrAllocating;
 

src/libcore/clone.rs

@@ -131,7 +131,7 @@ mod test {
     fn test_owned_clone() {
         let a = box 5i;
         let b: Box<int> = realclone(&a);
-        assert_eq!(a, b);
+        assert!(a == b);
     }
 
     #[test]

src/libcore/cmp.rs

@@ -82,7 +82,7 @@ pub trait TotalEq: Eq {
 }
 
 /// An ordering is, e.g, a result of a comparison between two values.
-#[deriving(Clone, Eq)]
+#[deriving(Clone, Eq, Show)]
 pub enum Ordering {
    /// An ordering where a compared value is less [than another].
    Less = -1,

src/libcore/failure.rs

@@ -9,21 +9,28 @@
 // except according to those terms.
 
 //! Failure support for libcore
+//!
+//! The core library cannot define failure, but it does *declare* failure. This
+//! means that the functions inside of libcore are allowed to fail, but to be
+//! useful an upstream crate must define failure for libcore to use. The current
+//! interface for failure is:
+//!
+//!     fn begin_unwind(fmt: &fmt::Arguments, file: &str, line: uint) -> !;
+//!
+//! This definition allows for failing with any general message, but it does not
+//! allow for failing with a `~Any` value. The reason for this is that libcore
+//! is not allowed to allocate.
+//!
+//! This module contains a few other failure functions, but these are just the
+//! necessary lang items for the compiler. All failure is funneled through this
+//! one function. Currently, the actual symbol is declared in the standard
+//! library, but the location of this may change over time.
 
 #![allow(dead_code, missing_doc)]
 
 #[cfg(not(test))]
 use str::raw::c_str_to_static_slice;
-
-// FIXME: Once std::fmt is in libcore, all of these functions should delegate
-//        to a common failure function with this signature:
-//
-//          extern {
-//              fn rust_unwind(f: &fmt::Arguments, file: &str, line: uint) -> !;
-//          }
-//
-//        Each of these functions can create a temporary fmt::Arguments
-//        structure to pass to this function.
+use fmt;
 
 #[cold] #[inline(never)] // this is the slow path, always
 #[lang="fail_"]
@@ -32,24 +39,31 @@ fn fail_(expr: *u8, file: *u8, line: uint) -> ! {
     unsafe {
         let expr = c_str_to_static_slice(expr as *i8);
         let file = c_str_to_static_slice(file as *i8);
-        begin_unwind(expr, file, line)
+        format_args!(|args| -> () {
+            begin_unwind(args, file, line);
+        }, "{}", expr);
+
+        loop {}
     }
 }
 
 #[cold]
 #[lang="fail_bounds_check"]
 #[cfg(not(test))]
 fn fail_bounds_check(file: *u8, line: uint, index: uint, len: uint) -> ! {
-    #[allow(ctypes)]
-    extern { fn rust_fail_bounds_check(file: *u8, line: uint,
-                                       index: uint, len: uint,) -> !; }
-    unsafe { rust_fail_bounds_check(file, line, index, len) }
+    let file = unsafe { c_str_to_static_slice(file as *i8) };
+    format_args!(|args| -> () {
+        begin_unwind(args, file, line);
+    }, "index out of bounds: the len is {} but the index is {}", len, index);
+    loop {}
 }
 
 #[cold]
-pub fn begin_unwind(msg: &str, file: &'static str, line: uint) -> ! {
+pub fn begin_unwind(fmt: &fmt::Arguments, file: &'static str, line: uint) -> ! {
+    // FIXME: this should be a proper lang item, it should not just be some
+    //        undefined symbol sitting in the middle of nowhere.
     #[allow(ctypes)]
-    extern { fn rust_begin_unwind(msg: &str, file: &'static str,
+    extern { fn rust_begin_unwind(fmt: &fmt::Arguments, file: &'static str,
                                   line: uint) -> !; }
-    unsafe { rust_begin_unwind(msg, file, line) }
+    unsafe { rust_begin_unwind(fmt, file, line) }
 }