std: Move the bitflags! macro to a gated crate

In accordance with [collections reform part 2][rfc] this macro has been moved to
an external [bitflags crate][crate] which is [available though
crates.io][cratesio]. Inside the standard distribution the macro has been moved
to a crate called `rustc_bitflags` for current users to continue using.

[rfc]: https://github.com/rust-lang/rfcs/blob/master/text/0509-collections-reform-part-2.md
[crate]: https://github.com/rust-lang/bitflags
[cratesio]: http://crates.io/crates/bitflags

The major user of `bitflags!` in terms of a public-facing possibly-stable API
today is the `FilePermissions` structure inside of `std::io`. This user,
however, will likely no longer use `bitflags!` after I/O reform has landed. To
prevent breaking APIs today, this structure remains as-is.

Current users of the `bitflags!` macro should add this to their `Cargo.toml`:

    bitflags = "0.1"

and this to their crate root:

    #[macro_use] extern crate bitflags;

Due to the removal of a public macro, this is a:

[breaking-change]

2 files changed, 3 insertions, 479 deletions

diff --git a/src/libstd/bitflags.rs b/src/libstd/bitflags.rs
deleted file mode 100644
index 3a059766fef..00000000000
--- a/src/libstd/bitflags.rs
+++ /dev/null
@@ -1,475 +0,0 @@
-// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-#![unstable]
-
-//! A typesafe bitmask flag generator.
-
-/// The `bitflags!` macro generates a `struct` that holds a set of C-style
-/// bitmask flags. It is useful for creating typesafe wrappers for C APIs.
-///
-/// The flags should only be defined for integer types, otherwise unexpected
-/// type errors may occur at compile time.
-///
-/// # Example
-///
-/// ```{.rust}
-/// bitflags! {
-///     flags Flags: u32 {
-///         const FLAG_A       = 0b00000001,
-///         const FLAG_B       = 0b00000010,
-///         const FLAG_C       = 0b00000100,
-///         const FLAG_ABC     = FLAG_A.bits
-///                            | FLAG_B.bits
-///                            | FLAG_C.bits,
-///     }
-/// }
-///
-/// fn main() {
-///     let e1 = FLAG_A | FLAG_C;
-///     let e2 = FLAG_B | FLAG_C;
-///     assert!((e1 | e2) == FLAG_ABC);   // union
-///     assert!((e1 & e2) == FLAG_C);     // intersection
-///     assert!((e1 - e2) == FLAG_A);     // set difference
-///     assert!(!e2 == FLAG_A);           // set complement
-/// }
-/// ```
-///
-/// The generated `struct`s can also be extended with type and trait implementations:
-///
-/// ```{.rust}
-/// use std::fmt;
-///
-/// bitflags! {
-///     flags Flags: u32 {
-///         const FLAG_A   = 0b00000001,
-///         const FLAG_B   = 0b00000010,
-///     }
-/// }
-///
-/// impl Flags {
-///     pub fn clear(&mut self) {
-///         self.bits = 0;  // The `bits` field can be accessed from within the
-///                         // same module where the `bitflags!` macro was invoked.
-///     }
-/// }
-///
-/// impl fmt::Show for Flags {
-///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-///         write!(f, "hi!")
-///     }
-/// }
-///
-/// fn main() {
-///     let mut flags = FLAG_A | FLAG_B;
-///     flags.clear();
-///     assert!(flags.is_empty());
-///     assert_eq!(format!("{:?}", flags).as_slice(), "hi!");
-/// }
-/// ```
-///
-/// # Attributes
-///
-/// Attributes can be attached to the generated `struct` by placing them
-/// before the `flags` keyword.
-///
-/// # Derived traits
-///
-/// The `PartialEq` and `Clone` traits are automatically derived for the `struct` using
-/// the `deriving` attribute. Additional traits can be derived by providing an
-/// explicit `deriving` attribute on `flags`.
-///
-/// # Operators
-///
-/// The following operator traits are implemented for the generated `struct`:
-///
-/// - `BitOr`: union
-/// - `BitAnd`: intersection
-/// - `BitXor`: toggle
-/// - `Sub`: set difference
-/// - `Not`: set complement
-///
-/// # Methods
-///
-/// The following methods are defined for the generated `struct`:
-///
-/// - `empty`: an empty set of flags
-/// - `all`: the set of all flags
-/// - `bits`: the raw value of the flags currently stored
-/// - `from_bits`: convert from underlying bit representation, unless that
-///                representation contains bits that do not correspond to a flag
-/// - `from_bits_truncate`: convert from underlying bit representation, dropping
-///                         any bits that do not correspond to flags
-/// - `is_empty`: `true` if no flags are currently stored
-/// - `is_all`: `true` if all flags are currently set
-/// - `intersects`: `true` if there are flags common to both `self` and `other`
-/// - `contains`: `true` all of the flags in `other` are contained within `self`
-/// - `insert`: inserts the specified flags in-place
-/// - `remove`: removes the specified flags in-place
-/// - `toggle`: the specified flags will be inserted if not present, and removed
-///             if they are.
-#[macro_export]
-macro_rules! bitflags {
-    ($(#[$attr:meta])* flags $BitFlags:ident: $T:ty {
-        $($(#[$Flag_attr:meta])* const $Flag:ident = $value:expr),+
-    }) => {
-        #[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash)]
-        $(#[$attr])*
-        pub struct $BitFlags {
-            bits: $T,
-        }
-
-        $($(#[$Flag_attr])* pub const $Flag: $BitFlags = $BitFlags { bits: $value };)+
-
-        impl $BitFlags {
-            /// Returns an empty set of flags.
-            #[inline]
-            pub fn empty() -> $BitFlags {
-                $BitFlags { bits: 0 }
-            }
-
-            /// Returns the set containing all flags.
-            #[inline]
-            pub fn all() -> $BitFlags {
-                $BitFlags { bits: $($value)|+ }
-            }
-
-            /// Returns the raw value of the flags currently stored.
-            #[inline]
-            pub fn bits(&self) -> $T {
-                self.bits
-            }
-
-            /// Convert from underlying bit representation, unless that
-            /// representation contains bits that do not correspond to a flag.
-            #[inline]
-            pub fn from_bits(bits: $T) -> ::std::option::Option<$BitFlags> {
-                if (bits & !$BitFlags::all().bits()) != 0 {
-                    ::std::option::Option::None
-                } else {
-                    ::std::option::Option::Some($BitFlags { bits: bits })
-                }
-            }
-
-            /// Convert from underlying bit representation, dropping any bits
-            /// that do not correspond to flags.
-            #[inline]
-            pub fn from_bits_truncate(bits: $T) -> $BitFlags {
-                $BitFlags { bits: bits } & $BitFlags::all()
-            }
-
-            /// Returns `true` if no flags are currently stored.
-            #[inline]
-            pub fn is_empty(&self) -> bool {
-                *self == $BitFlags::empty()
-            }
-
-            /// Returns `true` if all flags are currently set.
-            #[inline]
-            pub fn is_all(&self) -> bool {
-                *self == $BitFlags::all()
-            }
-
-            /// Returns `true` if there are flags common to both `self` and `other`.
-            #[inline]
-            pub fn intersects(&self, other: $BitFlags) -> bool {
-                !(*self & other).is_empty()
-            }
-
-            /// Returns `true` all of the flags in `other` are contained within `self`.
-            #[inline]
-            pub fn contains(&self, other: $BitFlags) -> bool {
-                (*self & other) == other
-            }
-
-            /// Inserts the specified flags in-place.
-            #[inline]
-            pub fn insert(&mut self, other: $BitFlags) {
-                self.bits |= other.bits;
-            }
-
-            /// Removes the specified flags in-place.
-            #[inline]
-            pub fn remove(&mut self, other: $BitFlags) {
-                self.bits &= !other.bits;
-            }
-
-            /// Toggles the specified flags in-place.
-            #[inline]
-            pub fn toggle(&mut self, other: $BitFlags) {
-                self.bits ^= other.bits;
-            }
-        }
-
-        impl ::std::ops::BitOr for $BitFlags {
-            type Output = $BitFlags;
-
-            /// Returns the union of the two sets of flags.
-            #[inline]
-            fn bitor(self, other: $BitFlags) -> $BitFlags {
-                $BitFlags { bits: self.bits | other.bits }
-            }
-        }
-
-        impl ::std::ops::BitXor for $BitFlags {
-            type Output = $BitFlags;
-
-            /// Returns the left flags, but with all the right flags toggled.
-            #[inline]
-            fn bitxor(self, other: $BitFlags) -> $BitFlags {
-                $BitFlags { bits: self.bits ^ other.bits }
-            }
-        }
-
-        impl ::std::ops::BitAnd for $BitFlags {
-            type Output = $BitFlags;
-
-            /// Returns the intersection between the two sets of flags.
-            #[inline]
-            fn bitand(self, other: $BitFlags) -> $BitFlags {
-                $BitFlags { bits: self.bits & other.bits }
-            }
-        }
-
-        impl ::std::ops::Sub for $BitFlags {
-            type Output = $BitFlags;
-
-            /// Returns the set difference of the two sets of flags.
-            #[inline]
-            fn sub(self, other: $BitFlags) -> $BitFlags {
-                $BitFlags { bits: self.bits & !other.bits }
-            }
-        }
-
-        impl ::std::ops::Not for $BitFlags {
-            type Output = $BitFlags;
-
-            /// Returns the complement of this set of flags.
-            #[inline]
-            fn not(self) -> $BitFlags {
-                $BitFlags { bits: !self.bits } & $BitFlags::all()
-            }
-        }
-    };
-    ($(#[$attr:meta])* flags $BitFlags:ident: $T:ty {
-        $($(#[$Flag_attr:meta])* const $Flag:ident = $value:expr),+,
-    }) => {
-        bitflags! {
-            $(#[$attr])*
-            flags $BitFlags: $T {
-                $($(#[$Flag_attr])* const $Flag = $value),+
-            }
-        }
-    };
-}
-
-#[cfg(test)]
-#[allow(non_upper_case_globals)]
-mod tests {
-    use hash::{self, SipHasher};
-    use option::Option::{Some, None};
-
-    bitflags! {
-        #[doc = "> The first principle is that you must not fool yourself — and"]
-        #[doc = "> you are the easiest person to fool."]
-        #[doc = "> "]
-        #[doc = "> - Richard Feynman"]
-        flags Flags: u32 {
-            const FlagA       = 0b00000001,
-            #[doc = "<pcwalton> macros are way better at generating code than trans is"]
-            const FlagB       = 0b00000010,
-            const FlagC       = 0b00000100,
-            #[doc = "* cmr bed"]
-            #[doc = "* strcat table"]
-            #[doc = "<strcat> wait what?"]
-            const FlagABC     = FlagA.bits
-                               | FlagB.bits
-                               | FlagC.bits,
-        }
-    }
-
-    bitflags! {
-        flags AnotherSetOfFlags: i8 {
-            const AnotherFlag = -1_i8,
-        }
-    }
-
-    #[test]
-    fn test_bits(){
-        assert_eq!(Flags::empty().bits(), 0b00000000);
-        assert_eq!(FlagA.bits(), 0b00000001);
-        assert_eq!(FlagABC.bits(), 0b00000111);
-
-        assert_eq!(AnotherSetOfFlags::empty().bits(), 0b00);
-        assert_eq!(AnotherFlag.bits(), !0_i8);
-    }
-
-    #[test]
-    fn test_from_bits() {
-        assert!(Flags::from_bits(0) == Some(Flags::empty()));
-        assert!(Flags::from_bits(0b1) == Some(FlagA));
-        assert!(Flags::from_bits(0b10) == Some(FlagB));
-        assert!(Flags::from_bits(0b11) == Some(FlagA | FlagB));
-        assert!(Flags::from_bits(0b1000) == None);
-
-        assert!(AnotherSetOfFlags::from_bits(!0_i8) == Some(AnotherFlag));
-    }
-
-    #[test]
-    fn test_from_bits_truncate() {
-        assert!(Flags::from_bits_truncate(0) == Flags::empty());
-        assert!(Flags::from_bits_truncate(0b1) == FlagA);
-        assert!(Flags::from_bits_truncate(0b10) == FlagB);
-        assert!(Flags::from_bits_truncate(0b11) == (FlagA | FlagB));
-        assert!(Flags::from_bits_truncate(0b1000) == Flags::empty());
-        assert!(Flags::from_bits_truncate(0b1001) == FlagA);
-
-        assert!(AnotherSetOfFlags::from_bits_truncate(0_i8) == AnotherSetOfFlags::empty());
-    }
-
-    #[test]
-    fn test_is_empty(){
-        assert!(Flags::empty().is_empty());
-        assert!(!FlagA.is_empty());
-        assert!(!FlagABC.is_empty());
-
-        assert!(!AnotherFlag.is_empty());
-    }
-
-    #[test]
-    fn test_is_all() {
-        assert!(Flags::all().is_all());
-        assert!(!FlagA.is_all());
-        assert!(FlagABC.is_all());
-
-        assert!(AnotherFlag.is_all());
-    }
-
-    #[test]
-    fn test_two_empties_do_not_intersect() {
-        let e1 = Flags::empty();
-        let e2 = Flags::empty();
-        assert!(!e1.intersects(e2));
-
-        assert!(AnotherFlag.intersects(AnotherFlag));
-    }
-
-    #[test]
-    fn test_empty_does_not_intersect_with_full() {
-        let e1 = Flags::empty();
-        let e2 = FlagABC;
-        assert!(!e1.intersects(e2));
-    }
-
-    #[test]
-    fn test_disjoint_intersects() {
-        let e1 = FlagA;
-        let e2 = FlagB;
-        assert!(!e1.intersects(e2));
-    }
-
-    #[test]
-    fn test_overlapping_intersects() {
-        let e1 = FlagA;
-        let e2 = FlagA | FlagB;
-        assert!(e1.intersects(e2));
-    }
-
-    #[test]
-    fn test_contains() {
-        let e1 = FlagA;
-        let e2 = FlagA | FlagB;
-        assert!(!e1.contains(e2));
-        assert!(e2.contains(e1));
-        assert!(FlagABC.contains(e2));
-
-        assert!(AnotherFlag.contains(AnotherFlag));
-    }
-
-    #[test]
-    fn test_insert(){
-        let mut e1 = FlagA;
-        let e2 = FlagA | FlagB;
-        e1.insert(e2);
-        assert!(e1 == e2);
-
-        let mut e3 = AnotherSetOfFlags::empty();
-        e3.insert(AnotherFlag);
-        assert!(e3 == AnotherFlag);
-    }
-
-    #[test]
-    fn test_remove(){
-        let mut e1 = FlagA | FlagB;
-        let e2 = FlagA | FlagC;
-        e1.remove(e2);
-        assert!(e1 == FlagB);
-
-        let mut e3 = AnotherFlag;
-        e3.remove(AnotherFlag);
-        assert!(e3 == AnotherSetOfFlags::empty());
-    }
-
-    #[test]
-    fn test_operators() {
-        let e1 = FlagA | FlagC;
-        let e2 = FlagB | FlagC;
-        assert!((e1 | e2) == FlagABC);     // union
-        assert!((e1 & e2) == FlagC);       // intersection
-        assert!((e1 - e2) == FlagA);       // set difference
-        assert!(!e2 == FlagA);             // set complement
-        assert!(e1 ^ e2 == FlagA | FlagB); // toggle
-        let mut e3 = e1;
-        e3.toggle(e2);
-        assert!(e3 == FlagA | FlagB);
-
-        let mut m4 = AnotherSetOfFlags::empty();
-        m4.toggle(AnotherSetOfFlags::empty());
-        assert!(m4 == AnotherSetOfFlags::empty());
-    }
-
-    #[test]
-    fn test_lt() {
-        let mut a = Flags::empty();
-        let mut b = Flags::empty();
-
-        assert!(!(a < b) && !(b < a));
-        b = FlagB;
-        assert!(a < b);
-        a = FlagC;
-        assert!(!(a < b) && b < a);
-        b = FlagC | FlagB;
-        assert!(a < b);
-    }
-
-    #[test]
-    fn test_ord() {
-        let mut a = Flags::empty();
-        let mut b = Flags::empty();
-
-        assert!(a <= b && a >= b);
-        a = FlagA;
-        assert!(a > b && a >= b);
-        assert!(b < a && b <= a);
-        b = FlagB;
-        assert!(b > a && b >= a);
-        assert!(a < b && a <= b);
-    }
-
-    #[test]
-    fn test_hash() {
-      let mut x = Flags::empty();
-      let mut y = Flags::empty();
-      assert!(hash::hash::<Flags, SipHasher>(&x) == hash::hash::<Flags, SipHasher>(&y));
-      x = Flags::all();
-      y = FlagABC;
-      assert!(hash::hash::<Flags, SipHasher>(&x) == hash::hash::<Flags, SipHasher>(&y));
-    }
-}
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index 182344452a4..2553bbdf523 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -111,7 +111,7 @@
 #![feature(box_syntax)]
 #![feature(old_impl_check)]
 #![feature(optin_builtin_traits)]
-#![allow(unknown_features)] #![feature(int_uint)]
+#![feature(int_uint)]
 
 // Don't link to std. We are std.
 #![no_std]
@@ -136,6 +136,8 @@ extern crate alloc;
 extern crate unicode;
 extern crate libc;
 
+#[macro_use] #[no_link] extern crate rustc_bitflags;
+
 // Make std testable by not duplicating lang items. See #2912
 #[cfg(test)] extern crate "std" as realstd;
 #[cfg(test)] pub use realstd::marker;
@@ -181,9 +183,6 @@ pub use unicode::char;
 #[macro_use]
 mod macros;
 
-#[macro_use]
-pub mod bitflags;
-
 mod rtdeps;
 
 /* The Prelude. */