std: Add io module again
#21835
std: Add io module again
#21835
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r? @aturon (rust_highfive has picked a reviewer for you, use r? to override) |
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Note that rust-lang/rfcs#576 has not yet been merged, so this should hold off on merging until that happens. |
| unsafe { | ||
| let other = ptr::read(self); | ||
| *self = &mut other[amt..]; | ||
| } |
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I was unable to figure out a safe way of doing this, but I have a feeling one may be lurking somewhere, certainly open to suggestions!
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This works (see in playpen):
fn cut<T>(xs: &mut &mut [T], amt: usize) {
let original = mem::replace(xs, &mut []);
mem::replace(xs, &mut original[amt..]);
}
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⌛ Testing commit 5cf9905 with merge 9830b16... |
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💔 Test failed - auto-linux-64-x-android-t |
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💔 Test failed - auto-win-32-opt |
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💔 Test failed - auto-linux-32-opt |
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@bors: retry |
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⌛ Testing commit 5cf9905 with merge bc16888... |
This commit is an implementation of [RFC 576][rfc] which adds back the `std::io` module to the standard library. No functionality in `std::old_io` has been deprecated just yet, and the new `std::io` module is behind the same `io` feature gate. [rfc]: rust-lang/rfcs#576 A good bit of functionality was copied over from `std::old_io`, but many tweaks were required for the new method signatures. Behavior such as precisely when buffered objects call to the underlying object may have been tweaked slightly in the transition. All implementations were audited to use composition wherever possible. For example the custom `pos` and `cap` cursors in `BufReader` were removed in favor of just using `Cursor<Vec<u8>>`. A few liberties were taken during this implementation which were not explicitly spelled out in the RFC: * The old `LineBufferedWriter` is now named `LineWriter` * The internal representation of `Error` now favors OS error codes (a 0-allocation path) and contains a `Box` for extra semantic data. * The io prelude currently reexports `Seek` as `NewSeek` to prevent conflicts with the real prelude reexport of `old_io::Seek` * The `chars` method was moved from `BufReadExt` to `ReadExt`. * The `chars` iterator returns a custom error with a variant that explains that the data was not valid UTF-8.
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💔 Test failed - auto-linux-64-x-android-t |
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@bors: retry |
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⌛ Testing commit 5cf9905 with merge 661a65e... |
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💔 Test failed - auto-linux-64-x-android-t |
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@bors: retry |
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⌛ Testing commit 5cf9905 with merge b74eef5... |
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💔 Test failed - auto-linux-64-x-android-t |
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@bors: retry |
1 similar comment
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@bors: retry |
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⌛ Testing commit 5cf9905 with merge 6a02f98... |
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💔 Test failed - auto-linux-64-x-android-t |
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@bors: retry |
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| // Semi-hack used to prevent LLVM from retaining any assumptions about | ||
| // `dummy` over this function call | ||
| unsafe fn black_box<T>(mut dummy: T) -> T { |
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Perhaps we should move this out of test into std::mem or something
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It is not related to memory, though. I find test be a better location for this.
This commit is an implementation of RFC 576 which adds back the
std::iomodule to the standard library. No functionality in
std::old_iohas beendeprecated just yet, and the new
std::iomodule is behind the sameiofeature gate.
A good bit of functionality was copied over from
std::old_io, but many tweakswere required for the new method signatures. Behavior such as precisely when
buffered objects call to the underlying object may have been tweaked slightly in
the transition. All implementations were audited to use composition wherever
possible. For example the custom
posandcapcursors inBufReaderwereremoved in favor of just using
Cursor<Vec<u8>>.A few liberties were taken during this implementation which were not explicitly
spelled out in the RFC:
LineBufferedWriteris now namedLineWriterErrornow favors OS error codes (a0-allocation path) and contains a
Boxfor extra semantic data.SeekasNewSeekto prevent conflictswith the real prelude reexport of
old_io::Seekcharsmethod was moved fromBufReadExttoReadExt.charsiterator returns a custom error with a variant that explains thatthe data was not valid UTF-8.