//! The module defining custom leveldb error type.

use libc::{c_void, free};
use std;

/// A leveldb error, just containing the error string
/// provided by leveldb.
#[derive(Debug)]
pub struct Error {
    message: String,
}

impl Error {
    /// create a new Error, using the String provided
    pub fn new(message: String) -> Error {
        Error { message: message }
    }

    /// create an error from a c-string buffer.
    pub fn new_from_i8(message: *const i8) -> Error {
        use std::str::from_utf8;
        use std::ffi::CStr;

        let err_string =
            unsafe { from_utf8(CStr::from_ptr(message).to_bytes()).unwrap().to_string() };
        unsafe { free(message as *mut c_void) };
        Error::new(err_string)
    }
}

impl std::fmt::Display for Error {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        write!(f, "LevelDB error: {}", self.message)
    }
}

impl std::error::Error for Error {
    fn description(&self) -> &str {
        &self.message
    }
    fn cause(&self) -> Option<&std::error::Error> {
        None
    }
}