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authorValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
committerValentin Popov <valentin@popov.link>2024-01-08 00:21:28 +0300
commit1b6a04ca5504955c571d1c97504fb45ea0befee4 (patch)
tree7579f518b23313e8a9748a88ab6173d5e030b227 /vendor/tempfile/src/spooled.rs
parent5ecd8cf2cba827454317368b68571df0d13d7842 (diff)
downloadfparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.tar.xz
fparkan-1b6a04ca5504955c571d1c97504fb45ea0befee4.zip
Initial vendor packages
Signed-off-by: Valentin Popov <valentin@popov.link>
Diffstat (limited to 'vendor/tempfile/src/spooled.rs')
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+use crate::file::tempfile;
+use std::fs::File;
+use std::io::{self, Cursor, Read, Seek, SeekFrom, Write};
+
+/// A wrapper for the two states of a `SpooledTempFile`.
+#[derive(Debug)]
+pub enum SpooledData {
+ InMemory(Cursor<Vec<u8>>),
+ OnDisk(File),
+}
+
+/// An object that behaves like a regular temporary file, but keeps data in
+/// memory until it reaches a configured size, at which point the data is
+/// written to a temporary file on disk, and further operations use the file
+/// on disk.
+#[derive(Debug)]
+pub struct SpooledTempFile {
+ max_size: usize,
+ inner: SpooledData,
+}
+
+/// Create a new spooled temporary file.
+///
+/// # Security
+///
+/// This variant is secure/reliable in the presence of a pathological temporary
+/// file cleaner.
+///
+/// # Resource Leaking
+///
+/// The temporary file will be automatically removed by the OS when the last
+/// handle to it is closed. This doesn't rely on Rust destructors being run, so
+/// will (almost) never fail to clean up the temporary file.
+///
+/// # Examples
+///
+/// ```
+/// use tempfile::spooled_tempfile;
+/// use std::io::{self, Write};
+///
+/// # fn main() {
+/// # if let Err(_) = run() {
+/// # ::std::process::exit(1);
+/// # }
+/// # }
+/// # fn run() -> Result<(), io::Error> {
+/// let mut file = spooled_tempfile(15);
+///
+/// writeln!(file, "short line")?;
+/// assert!(!file.is_rolled());
+///
+/// // as a result of this write call, the size of the data will exceed
+/// // `max_size` (15), so it will be written to a temporary file on disk,
+/// // and the in-memory buffer will be dropped
+/// writeln!(file, "marvin gardens")?;
+/// assert!(file.is_rolled());
+///
+/// # Ok(())
+/// # }
+/// ```
+#[inline]
+pub fn spooled_tempfile(max_size: usize) -> SpooledTempFile {
+ SpooledTempFile::new(max_size)
+}
+
+impl SpooledTempFile {
+ #[must_use]
+ pub fn new(max_size: usize) -> SpooledTempFile {
+ SpooledTempFile {
+ max_size,
+ inner: SpooledData::InMemory(Cursor::new(Vec::new())),
+ }
+ }
+
+ /// Returns true if the file has been rolled over to disk.
+ #[must_use]
+ pub fn is_rolled(&self) -> bool {
+ match self.inner {
+ SpooledData::InMemory(_) => false,
+ SpooledData::OnDisk(_) => true,
+ }
+ }
+
+ /// Rolls over to a file on disk, regardless of current size. Does nothing
+ /// if already rolled over.
+ pub fn roll(&mut self) -> io::Result<()> {
+ if !self.is_rolled() {
+ let mut file = tempfile()?;
+ if let SpooledData::InMemory(cursor) = &mut self.inner {
+ file.write_all(cursor.get_ref())?;
+ file.seek(SeekFrom::Start(cursor.position()))?;
+ }
+ self.inner = SpooledData::OnDisk(file);
+ }
+ Ok(())
+ }
+
+ pub fn set_len(&mut self, size: u64) -> Result<(), io::Error> {
+ if size as usize > self.max_size {
+ self.roll()?; // does nothing if already rolled over
+ }
+ match &mut self.inner {
+ SpooledData::InMemory(cursor) => {
+ cursor.get_mut().resize(size as usize, 0);
+ Ok(())
+ }
+ SpooledData::OnDisk(file) => file.set_len(size),
+ }
+ }
+
+ /// Consumes and returns the inner `SpooledData` type.
+ #[must_use]
+ pub fn into_inner(self) -> SpooledData {
+ self.inner
+ }
+}
+
+impl Read for SpooledTempFile {
+ fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
+ match &mut self.inner {
+ SpooledData::InMemory(cursor) => cursor.read(buf),
+ SpooledData::OnDisk(file) => file.read(buf),
+ }
+ }
+
+ fn read_vectored(&mut self, bufs: &mut [io::IoSliceMut<'_>]) -> io::Result<usize> {
+ match &mut self.inner {
+ SpooledData::InMemory(cursor) => cursor.read_vectored(bufs),
+ SpooledData::OnDisk(file) => file.read_vectored(bufs),
+ }
+ }
+
+ fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
+ match &mut self.inner {
+ SpooledData::InMemory(cursor) => cursor.read_to_end(buf),
+ SpooledData::OnDisk(file) => file.read_to_end(buf),
+ }
+ }
+
+ fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
+ match &mut self.inner {
+ SpooledData::InMemory(cursor) => cursor.read_to_string(buf),
+ SpooledData::OnDisk(file) => file.read_to_string(buf),
+ }
+ }
+
+ fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
+ match &mut self.inner {
+ SpooledData::InMemory(cursor) => cursor.read_exact(buf),
+ SpooledData::OnDisk(file) => file.read_exact(buf),
+ }
+ }
+}
+
+impl Write for SpooledTempFile {
+ fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+ // roll over to file if necessary
+ if matches! {
+ &self.inner, SpooledData::InMemory(cursor)
+ if cursor.position() as usize + buf.len() > self.max_size
+ } {
+ self.roll()?;
+ }
+
+ // write the bytes
+ match &mut self.inner {
+ SpooledData::InMemory(cursor) => cursor.write(buf),
+ SpooledData::OnDisk(file) => file.write(buf),
+ }
+ }
+
+ fn write_vectored(&mut self, bufs: &[io::IoSlice<'_>]) -> io::Result<usize> {
+ if matches! {
+ &self.inner, SpooledData::InMemory(cursor)
+ // Borrowed from the rust standard library.
+ if cursor.position() as usize + bufs.iter()
+ .fold(0usize, |a, b| a.saturating_add(b.len())) > self.max_size
+ } {
+ self.roll()?;
+ }
+ match &mut self.inner {
+ SpooledData::InMemory(cursor) => cursor.write_vectored(bufs),
+ SpooledData::OnDisk(file) => file.write_vectored(bufs),
+ }
+ }
+
+ #[inline]
+ fn flush(&mut self) -> io::Result<()> {
+ match &mut self.inner {
+ SpooledData::InMemory(cursor) => cursor.flush(),
+ SpooledData::OnDisk(file) => file.flush(),
+ }
+ }
+}
+
+impl Seek for SpooledTempFile {
+ fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
+ match &mut self.inner {
+ SpooledData::InMemory(cursor) => cursor.seek(pos),
+ SpooledData::OnDisk(file) => file.seek(pos),
+ }
+ }
+}