diff options
| -rw-r--r-- | src/services/fs.rs | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/src/services/fs.rs b/src/services/fs.rs index 188fe4c..8a0829e 100644 --- a/src/services/fs.rs +++ b/src/services/fs.rs @@ -1,5 +1,6 @@ use core::marker::PhantomData; use core::ptr; +use core::slice; use collections::Vec; use path::Path; @@ -151,6 +152,12 @@ impl File { } } + pub fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, i32> { + unsafe { + read_to_end_uninitialized(self, buf) + } + } + pub fn write(&mut self, buf: &[u8]) -> Result<usize, i32> { unsafe { let mut n_written = 0; @@ -249,6 +256,33 @@ pub fn remove_file<P: AsRef<Path>>(arch: &Archive, path: P) -> Result<(), i32> { } } +// Adapted from sys/common/io.rs in libstd +unsafe fn read_to_end_uninitialized(f: &mut File, buf: &mut Vec<u8>) -> Result<usize, i32> { + let start_len = buf.len(); + buf.reserve(16); + + // Always try to read into the empty space of the vector (from the length to the capacity). + // If the vector ever fills up then we reserve an extra byte which should trigger the normal + // reallocation routines for the vector, which will likely double the size. + // + // This function is similar to the read_to_end function in std::io, but the logic about + // reservations and slicing is different enough that this is duplicated here. + loop { + if buf.len() == buf.capacity() { + buf.reserve(1); + } + + let buf_slice = slice::from_raw_parts_mut(buf.as_mut_ptr().offset(buf.len() as isize), + buf.capacity() - buf.len()); + + match f.read(buf_slice) { + Ok(0) => { return Ok(buf.len() - start_len); } + Ok(n) => { let len = buf.len() + n; buf.set_len(len); }, + Err(e) => { return Err(e); } + } + } +} + impl Drop for Fs { fn drop(&mut self) { unsafe { |