forked from mirror/async-std
50 lines
1.6 KiB
Rust
50 lines
1.6 KiB
Rust
use crate::io;
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use crate::path::Path;
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use crate::task::spawn_blocking;
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use crate::utils::Context as _;
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/// Copies the contents and permissions of a file to a new location.
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///
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/// On success, the total number of bytes copied is returned and equals the length of the `to` file
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/// after this operation.
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///
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/// The old contents of `to` will be overwritten. If `from` and `to` both point to the same file,
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/// then the file will likely get truncated as a result of this operation.
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///
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/// If you're working with open [`File`]s and want to copy contents through those types, use the
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/// [`io::copy`] function.
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///
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/// This function is an async version of [`std::fs::copy`].
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///
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/// [`File`]: struct.File.html
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/// [`io::copy`]: ../io/fn.copy.html
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/// [`std::fs::copy`]: https://doc.rust-lang.org/std/fs/fn.copy.html
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///
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/// # Errors
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///
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/// An error will be returned in the following situations:
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///
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/// * `from` does not point to an existing file.
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/// * The current process lacks permissions to read `from` or write `to`.
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/// * Some other I/O error occurred.
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///
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/// # Examples
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///
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/// ```no_run
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/// # fn main() -> std::io::Result<()> { async_std::task::block_on(async {
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/// #
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/// use async_std::fs;
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///
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/// let num_bytes = fs::copy("a.txt", "b.txt").await?;
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/// #
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/// # Ok(()) }) }
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/// ```
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pub async fn copy<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> io::Result<u64> {
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let from = from.as_ref().to_owned();
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let to = to.as_ref().to_owned();
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spawn_blocking(move || {
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std::fs::copy(&from, &to)
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.context(|| format!("could not copy `{}` to `{}`", from.display(), to.display()))
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})
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.await
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}
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