use checked write in LineWriter example
#51628
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src/libstd/io/buffered.rs
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| /// for &byte in road_not_taken.iter() { | ||
| /// file.write(&[byte]).unwrap(); | ||
| /// } | ||
| /// file.write_all(road_not_taken)?; |
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The example is explicitly writing each byte individually to note how the buffering provided by LineWriter helps things. If we were going to write the whole message out at once, there's no reason to use the LineWriter at all.
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It's still line buffering behind the scenes, so I don't think that it's totally wrong. I'm certainly open to suggestions on how to improve the entire example, though. Maybe we could write some bytes, and demonstrate that they aren't written to disk until a newline is written?
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Ping from triage, @withoutboats : This PR needs your review! |
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This isn't ready for review, I plan to rewrite the example per sfackler's review. |
The original example didn't check the return value of `write()`, didn't flush the writer, and didn't properly demonstrate the buffering. Fixes rust-lang#51621.
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@sfackler @withoutboats This is ready for another review. |
src/libstd/io/buffered.rs
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| /// | ||
| /// // No bytes are written until a newline is encountered (or | ||
| /// // the internal buffer is filled). | ||
| /// assert_eq!(fs::read_to_string("poem.txt")?.as_bytes(), b""); |
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I think fs::read_to_string(...)?.as_bytes() can just be fs::read(...)?
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Alternatively this can be assert_eq!(fs::read_to_string("poem.txt")?, "").
TimNN
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Ping from triage, @withoutboats: This PR is waiting for your review. |
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@bors r+ rollup |
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📌 Commit c12a757 has been approved by |
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use checked write in `LineWriter` example The example was wrong because it didn't check the return value of `write()`, and it didn't flush the buffer before comparing the contents of the file. Fixes rust-lang#51621.
Rollup of 13 pull requests Successful merges: - #51628 (use checked write in `LineWriter` example) - #52116 (Handle array manually in str case conversion methods) - #52218 (Amend option.take examples) - #52418 (Do not use desugared ident when suggesting adding a type) - #52439 (Revert some changes from #51917 to fix custom libdir) - #52455 (Fix doc comment: use `?` instead of `.unwrap()`) - #52458 (rustc: Fix a suggestion for the `proc_macro` feature) - #52464 (Allow clippy to be installed with make install) - #52472 (rustc: Enable `use_extern_macros` in 2018 edition) - #52477 (Clarify short-circuiting behvaior of Iterator::zip.) - #52480 (Cleanup #24958) - #52487 (Don't build twice the sanitizers on Linux) - #52510 (rustdoc: remove FIXME about macro redirects) Failed merges: r? @ghost
The example was wrong because it didn't check the return value of
write(), and it didn't flush the buffer before comparing the contentsof the file.
Fixes #51621.