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45 lines
1.3 KiB
Rust
45 lines
1.3 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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/// Reads the entire contents of a file as raw bytes.
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///
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/// This is a convenience function for reading entire files. It pre-allocates a buffer based on the
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/// file size when available, so it is typically faster than manually opening a file and reading
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/// from it.
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///
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/// If you want to read the contents as a string, use [`read_to_string`] instead.
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///
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/// This function is an async version of [`std::fs::read`].
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///
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/// [`read_to_string`]: fn.read_to_string.html
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/// [`std::fs::read`]: https://doc.rust-lang.org/std/fs/fn.read.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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/// * `path` does not point to an existing file.
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/// * The current process lacks permissions to read the file.
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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 contents = fs::read("a.txt").await?;
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/// #
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/// # Ok(()) }) }
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/// ```
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pub async fn read<P: AsRef<Path>>(path: P) -> io::Result<Vec<u8>> {
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let path = path.as_ref().to_owned();
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spawn_blocking(move || {
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std::fs::read(&path).context(|| format!("could not read file `{}`", path.display()))
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})
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.await
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}
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