Struct MmapInput

pub struct MmapInput { /* private fields */ }

Input wrapping a memory mapped file.

Implementations

impl MmapInput

pub unsafe fn map_file<D: MmapAsRawDesc>( file_desc: D, ) -> Result<Self, InputError>

Map a file to memory.

Safety

This operation is inherently unsafe, since the file can be modified in or out of process. See Mmap documentation.

Errors

Calling mmap might result in an IO error.

Examples found in repository

examples/approx_spans_usage.rs (line 22)

fn main() -> Result<ExitCode, Box<dyn Error>> {
    let args: Vec<_> = env::args().collect();

    if args.len() != 3 {
        eprintln!("provide exactly two arguments, query and file path");
        return Ok(ExitCode::FAILURE);
    }

    let query_arg = &args[1];
    let file_path = &args[2];

    let query = rsonpath_syntax::parse(query_arg)?;
    let file = fs::File::open(file_path)?;
    // SAFETY: File is kept open until end of the run.
    let input = unsafe { MmapInput::map_file(&file)? };
    let stdout_lock = io::stdout().lock();
    let mut sink = MatchWriter::from(stdout_lock);

    let engine = RsonpathEngine::compile_query(&query)?;

    engine.approximate_spans(&input, &mut sink)?;

    Ok(ExitCode::SUCCESS)
}

Trait Implementations

impl Input for MmapInput

type BlockIterator<'a, 'r, R, const N: usize> = BorrowedBytesBlockIterator<'r, EndPaddedInput<'a>, R, N> where R: InputRecorder<&'a [u8]> + 'r

Type of the iterator used by iter_blocks, parameterized by the lifetime of source input and the size of the block.

type Error = Infallible

Type of errors that can occur when operating on this Input.

type Block<'a, const N: usize> = &'a [u8]

Type of the blocks returned by the BlockIterator.

fn leading_padding_len(&self) -> usize

Return the length of the padding added at the start of the input.

fn trailing_padding_len(&self) -> usize

Return the length of the padding added at the end of the input.

fn len_hint(&self) -> Option<usize>

Return the length of the entire input, if known.

fn iter_blocks<'a, 'r, R, const N: usize>( &'a self, recorder: &'r R, ) -> Self::BlockIterator<'a, 'r, R, N>

where R: InputRecorder<&'a [u8]>,

Iterate over blocks of size N of the input. N has to be a power of two larger than 1.

fn seek_backward(&self, from: usize, needle: u8) -> Option<usize>

Search for an occurrence of needle in the input, starting from from and looking back. Returns the index of the first occurrence or None if the needle was not found.

fn seek_forward<const N: usize>( &self, from: usize, needles: [u8; N], ) -> Result<Option<(usize, u8)>, Infallible>

Search for an occurrence of any of the needles in the input, starting from from and looking forward. Returns the index of the first occurrence and the needle found, or None if none of the needles were not found.

fn seek_non_whitespace_forward( &self, from: usize, ) -> Result<Option<(usize, u8)>, Infallible>

Search for the first byte in the input that is not ASCII whitespace starting from from. Returns a pair: the index of first such byte, and the byte itself; or None if no non-whitespace characters were found.

fn seek_non_whitespace_backward(&self, from: usize) -> Option<(usize, u8)>

Search for the first byte in the input that is not ASCII whitespace starting from from and looking back. Returns a pair: the index of first such byte, and the byte itself; or None if no non-whitespace characters were found.

fn is_member_match( &self, from: usize, to: usize, member: &StringPattern, ) -> Result<bool, Self::Error>

Decide whether the slice of input between from (inclusive) and to (exclusive) matches the member (comparing bitwise, including double quotes delimiters).