46 lines
1.4 KiB
Rust
46 lines
1.4 KiB
Rust
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use std::io::Read;
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/// Read trait for tape devices
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///
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/// Normal Read, but allows to query additional status flags.
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pub trait TapeRead: Read {
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/// Return true if there is an "INCOMPLETE" mark at EOF
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///
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/// Raises an error if you query this flag before reaching EOF.
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fn is_incomplete(&self) -> Result<bool, std::io::Error>;
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/// Return true if there is a file end marker before EOF
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///
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/// Raises an error if you query this flag before reaching EOF.
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fn has_end_marker(&self) -> Result<bool, std::io::Error>;
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}
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/// Read a single block from a tape device
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///
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/// Assumes that 'reader' is a linux tape device.
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///
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/// Return true on success, false on EOD
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pub fn tape_device_read_block<R: Read>(
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reader: &mut R,
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buffer: &mut [u8],
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) -> Result<bool, std::io::Error> {
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loop {
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match reader.read(buffer) {
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Ok(0) => { return Ok(false); /* EOD */ }
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Ok(count) => {
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if count == buffer.len() {
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return Ok(true);
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}
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proxmox::io_bail!("short block read ({} < {}). Tape drive uses wrong block size.",
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count, buffer.len());
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}
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// handle interrupted system call
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Err(err) if err.kind() == std::io::ErrorKind::Interrupted => {
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continue;
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}
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Err(err) => return Err(err),
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}
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}
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}
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