/*

re2.rs

Rust FFI bindings to Re2.

Copyright 2020 Valentin Gatien-Baron

This software may be used and distributed according to the terms of the

GNU General Public License version 2 or any later version.

*/

use libc::{c_int, c_void};

type Re2Ptr = *const c_void;

pub struct Re2(Re2Ptr);

/// `re2.h` says:

/// "An "RE2" object is safe for concurrent use by multiple threads."

unsafe impl Sync for Re2 {}

/// These bind to the C ABI in `rust_re2.cpp`.

extern "C" {

    fn rust_re2_create(data: *const u8, len: usize) -> Re2Ptr;

    fn rust_re2_destroy(re2: Re2Ptr);

    fn rust_re2_ok(re2: Re2Ptr) -> bool;

    fn rust_re2_error(

        re2: Re2Ptr,

        outdata: *mut *const u8,

        outlen: *mut usize,

    ) -> bool;

    fn rust_re2_match(

        re2: Re2Ptr,

        data: *const u8,

        len: usize,

        anchor: c_int,

    ) -> bool;

}

impl Re2 {

    pub fn new(pattern: &[u8]) -> Result<Re2, String> {

        unsafe {

            let re2 = rust_re2_create(pattern.as_ptr(), pattern.len());

            if rust_re2_ok(re2) {

                Ok(Re2(re2))

            } else {

                let mut data: *const u8 = std::ptr::null();

                let mut len: usize = 0;

                rust_re2_error(re2, &mut data, &mut len);

                Err(String::from_utf8_lossy(std::slice::from_raw_parts(

                    data, len,

                ))

                .to_string())

            }

        }

    }

    pub fn is_match(&self, data: &[u8]) -> bool {

        unsafe { rust_re2_match(self.0, data.as_ptr(), data.len(), 1) }

    }

}

impl Drop for Re2 {

    fn drop(&mut self) {

        unsafe { rust_re2_destroy(self.0) }

    }

}