auto merge of #13049 : alexcrichton/rust/io-fill, r=huonw
This method can be used to fill a byte slice of data entirely, and it's considered an error if any error happens before its entirely filled.
This commit is contained in:
commit
e06348ea55
4 changed files with 40 additions and 11 deletions
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@ -60,10 +60,8 @@ impl<R: Reader> Rng for ReaderRng<R> {
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}
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fn fill_bytes(&mut self, v: &mut [u8]) {
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if v.len() == 0 { return }
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match self.reader.read(v) {
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Ok(n) if n == v.len() => return,
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Ok(n) => fail!("ReaderRng.fill_bytes could not fill buffer: \
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read {} out of {} bytes.", n, v.len()),
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match self.reader.fill(v) {
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Ok(()) => {}
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Err(e) => fail!("ReaderRng.fill_bytes error: {}", e)
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}
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}
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@ -86,7 +86,7 @@ impl<R: Reader> BufferedReader<R> {
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}
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impl<R: Reader> Buffer for BufferedReader<R> {
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fn fill<'a>(&'a mut self) -> IoResult<&'a [u8]> {
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fn fill_buf<'a>(&'a mut self) -> IoResult<&'a [u8]> {
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if self.pos == self.cap {
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self.cap = try!(self.inner.read(self.buf.as_mut_slice()));
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self.pos = 0;
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@ -103,7 +103,7 @@ impl<R: Reader> Buffer for BufferedReader<R> {
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impl<R: Reader> Reader for BufferedReader<R> {
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fn read(&mut self, buf: &mut [u8]) -> IoResult<uint> {
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let nread = {
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let available = try!(self.fill());
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let available = try!(self.fill_buf());
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let nread = cmp::min(available.len(), buf.len());
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slice::bytes::copy_memory(buf, available.slice_to(nread));
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nread
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@ -345,7 +345,7 @@ impl<S: Stream> BufferedStream<S> {
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}
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impl<S: Stream> Buffer for BufferedStream<S> {
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fn fill<'a>(&'a mut self) -> IoResult<&'a [u8]> { self.inner.fill() }
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fn fill_buf<'a>(&'a mut self) -> IoResult<&'a [u8]> { self.inner.fill_buf() }
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fn consume(&mut self, amt: uint) { self.inner.consume(amt) }
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}
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@ -190,7 +190,7 @@ impl Seek for MemReader {
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}
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impl Buffer for MemReader {
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fn fill<'a>(&'a mut self) -> IoResult<&'a [u8]> {
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fn fill_buf<'a>(&'a mut self) -> IoResult<&'a [u8]> {
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if self.pos < self.buf.len() {
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Ok(self.buf.slice_from(self.pos))
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} else {
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@ -322,7 +322,7 @@ impl<'a> Seek for BufReader<'a> {
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}
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impl<'a> Buffer for BufReader<'a> {
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fn fill<'a>(&'a mut self) -> IoResult<&'a [u8]> {
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fn fill_buf<'a>(&'a mut self) -> IoResult<&'a [u8]> {
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if self.pos < self.buf.len() {
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Ok(self.buf.slice_from(self.pos))
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} else {
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@ -555,4 +555,18 @@ mod test {
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let mut r = BufWriter::new(buf);
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assert!(r.seek(-1, SeekSet).is_err());
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}
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#[test]
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fn io_fill() {
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let mut r = MemReader::new(~[1, 2, 3, 4, 5, 6, 7, 8]);
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let mut buf = [0, ..3];
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assert_eq!(r.fill(buf), Ok(()));
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assert_eq!(buf.as_slice(), &[1, 2, 3]);
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assert_eq!(r.fill(buf.mut_slice_to(0)), Ok(()));
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assert_eq!(buf.as_slice(), &[1, 2, 3]);
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assert_eq!(r.fill(buf), Ok(()));
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assert_eq!(buf.as_slice(), &[4, 5, 6]);
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assert!(r.fill(buf).is_err());
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assert_eq!(buf.as_slice(), &[7, 8, 6]);
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}
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}
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@ -360,6 +360,23 @@ pub trait Reader {
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}
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}
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/// Fills the provided slice with bytes from this reader
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///
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/// This will continue to call `read` until the slice has been completely
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/// filled with bytes.
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///
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/// # Error
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///
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/// If an error occurs at any point, that error is returned, and no further
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/// bytes are read.
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fn fill(&mut self, buf: &mut [u8]) -> IoResult<()> {
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let mut read = 0;
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while read < buf.len() {
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read += try!(self.read(buf.mut_slice_from(read)));
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}
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Ok(())
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}
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/// Reads exactly `len` bytes and appends them to a vector.
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///
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/// May push fewer than the requested number of bytes on error
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@ -1045,7 +1062,7 @@ pub trait Buffer: Reader {
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/// This function will return an I/O error if the underlying reader was
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/// read, but returned an error. Note that it is not an error to return a
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/// 0-length buffer.
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fn fill<'a>(&'a mut self) -> IoResult<&'a [u8]>;
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fn fill_buf<'a>(&'a mut self) -> IoResult<&'a [u8]>;
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/// Tells this buffer that `amt` bytes have been consumed from the buffer,
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/// so they should no longer be returned in calls to `fill` or `read`.
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@ -1116,7 +1133,7 @@ pub trait Buffer: Reader {
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let mut used;
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loop {
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{
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let available = match self.fill() {
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let available = match self.fill_buf() {
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Ok(n) => n,
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Err(ref e) if res.len() > 0 && e.kind == EndOfFile => {
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used = 0;
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