aboutsummaryrefslogtreecommitdiff
path: root/ctr-std/src/sys/windows/ext/ffi.rs
diff options
context:
space:
mode:
authorValentin <[email protected]>2018-06-15 18:57:24 +0200
committerFenrirWolf <[email protected]>2018-06-15 10:57:24 -0600
commitf2a90174bb36b9ad528e863ab34c02ebce002b02 (patch)
tree959e8d67883d3a89e179b3549b1f30d28e51a87c /ctr-std/src/sys/windows/ext/ffi.rs
parentMerge pull request #68 from linouxis9/master (diff)
downloadctru-rs-f2a90174bb36b9ad528e863ab34c02ebce002b02.tar.xz
ctru-rs-f2a90174bb36b9ad528e863ab34c02ebce002b02.zip
Update for latest nightly 2018-06-09 (#70)
* Update for latest nightly 2018-06-09 * We now have a proper horizon os and sys modules in libstd
Diffstat (limited to 'ctr-std/src/sys/windows/ext/ffi.rs')
-rw-r--r--ctr-std/src/sys/windows/ext/ffi.rs151
1 files changed, 151 insertions, 0 deletions
diff --git a/ctr-std/src/sys/windows/ext/ffi.rs b/ctr-std/src/sys/windows/ext/ffi.rs
new file mode 100644
index 0000000..98d4355
--- /dev/null
+++ b/ctr-std/src/sys/windows/ext/ffi.rs
@@ -0,0 +1,151 @@
+// Copyright 2015 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.
+
+//! Windows-specific extensions to the primitives in the `std::ffi` module.
+//!
+//! # Overview
+//!
+//! For historical reasons, the Windows API uses a form of potentially
+//! ill-formed UTF-16 encoding for strings. Specifically, the 16-bit
+//! code units in Windows strings may contain [isolated surrogate code
+//! points which are not paired together][ill-formed-utf-16]. The
+//! Unicode standard requires that surrogate code points (those in the
+//! range U+D800 to U+DFFF) always be *paired*, because in the UTF-16
+//! encoding a *surrogate code unit pair* is used to encode a single
+//! character. For compatibility with code that does not enforce
+//! these pairings, Windows does not enforce them, either.
+//!
+//! While it is not always possible to convert such a string losslessly into
+//! a valid UTF-16 string (or even UTF-8), it is often desirable to be
+//! able to round-trip such a string from and to Windows APIs
+//! losslessly. For example, some Rust code may be "bridging" some
+//! Windows APIs together, just passing `WCHAR` strings among those
+//! APIs without ever really looking into the strings.
+//!
+//! If Rust code *does* need to look into those strings, it can
+//! convert them to valid UTF-8, possibly lossily, by substituting
+//! invalid sequences with U+FFFD REPLACEMENT CHARACTER, as is
+//! conventionally done in other Rust APIs that deal with string
+//! encodings.
+//!
+//! # `OsStringExt` and `OsStrExt`
+//!
+//! [`OsString`] is the Rust wrapper for owned strings in the
+//! preferred representation of the operating system. On Windows,
+//! this struct gets augmented with an implementation of the
+//! [`OsStringExt`] trait, which has a [`from_wide`] method. This
+//! lets you create an [`OsString`] from a `&[u16]` slice; presumably
+//! you get such a slice out of a `WCHAR` Windows API.
+//!
+//! Similarly, [`OsStr`] is the Rust wrapper for borrowed strings from
+//! preferred representation of the operating system. On Windows, the
+//! [`OsStrExt`] trait provides the [`encode_wide`] method, which
+//! outputs an [`EncodeWide`] iterator. You can [`collect`] this
+//! iterator, for example, to obtain a `Vec<u16>`; you can later get a
+//! pointer to this vector's contents and feed it to Windows APIs.
+//!
+//! These traits, along with [`OsString`] and [`OsStr`], work in
+//! conjunction so that it is possible to **round-trip** strings from
+//! Windows and back, with no loss of data, even if the strings are
+//! ill-formed UTF-16.
+//!
+//! [ill-formed-utf-16]: https://simonsapin.github.io/wtf-8/#ill-formed-utf-16
+//! [`OsString`]: ../../../ffi/struct.OsString.html
+//! [`OsStr`]: ../../../ffi/struct.OsStr.html
+//! [`OsStringExt`]: trait.OsStringExt.html
+//! [`OsStrExt`]: trait.OsStrExt.html
+//! [`EncodeWide`]: struct.EncodeWide.html
+//! [`from_wide`]: trait.OsStringExt.html#tymethod.from_wide
+//! [`encode_wide`]: trait.OsStrExt.html#tymethod.encode_wide
+//! [`collect`]: ../../../iter/trait.Iterator.html#method.collect
+
+#![stable(feature = "rust1", since = "1.0.0")]
+
+use ffi::{OsString, OsStr};
+use sys::os_str::Buf;
+use sys_common::wtf8::Wtf8Buf;
+use sys_common::{FromInner, AsInner};
+
+#[stable(feature = "rust1", since = "1.0.0")]
+pub use sys_common::wtf8::EncodeWide;
+
+/// Windows-specific extensions to [`OsString`].
+///
+/// [`OsString`]: ../../../../std/ffi/struct.OsString.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait OsStringExt {
+ /// Creates an `OsString` from a potentially ill-formed UTF-16 slice of
+ /// 16-bit code units.
+ ///
+ /// This is lossless: calling [`encode_wide`] on the resulting string
+ /// will always return the original code units.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::ffi::OsString;
+ /// use std::os::windows::prelude::*;
+ ///
+ /// // UTF-16 encoding for "Unicode".
+ /// let source = [0x0055, 0x006E, 0x0069, 0x0063, 0x006F, 0x0064, 0x0065];
+ ///
+ /// let string = OsString::from_wide(&source[..]);
+ /// ```
+ ///
+ /// [`encode_wide`]: ./trait.OsStrExt.html#tymethod.encode_wide
+ #[stable(feature = "rust1", since = "1.0.0")]
+ fn from_wide(wide: &[u16]) -> Self;
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl OsStringExt for OsString {
+ fn from_wide(wide: &[u16]) -> OsString {
+ FromInner::from_inner(Buf { inner: Wtf8Buf::from_wide(wide) })
+ }
+}
+
+/// Windows-specific extensions to [`OsStr`].
+///
+/// [`OsStr`]: ../../../../std/ffi/struct.OsStr.html
+#[stable(feature = "rust1", since = "1.0.0")]
+pub trait OsStrExt {
+ /// Re-encodes an `OsStr` as a wide character sequence, i.e. potentially
+ /// ill-formed UTF-16.
+ ///
+ /// This is lossless: calling [`OsString::from_wide`] and then
+ /// `encode_wide` on the result will yield the original code units.
+ /// Note that the encoding does not add a final null terminator.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use std::ffi::OsString;
+ /// use std::os::windows::prelude::*;
+ ///
+ /// // UTF-16 encoding for "Unicode".
+ /// let source = [0x0055, 0x006E, 0x0069, 0x0063, 0x006F, 0x0064, 0x0065];
+ ///
+ /// let string = OsString::from_wide(&source[..]);
+ ///
+ /// let result: Vec<u16> = string.encode_wide().collect();
+ /// assert_eq!(&source[..], &result[..]);
+ /// ```
+ ///
+ /// [`OsString::from_wide`]: ./trait.OsStringExt.html#tymethod.from_wide
+ #[stable(feature = "rust1", since = "1.0.0")]
+ fn encode_wide(&self) -> EncodeWide;
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl OsStrExt for OsStr {
+ fn encode_wide(&self) -> EncodeWide {
+ self.as_inner().inner.encode_wide()
+ }
+}