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use std::io::{BufRead, BufReader, Lines, Read};
use crate::error::WithOrExit;
use std::fs::File;
use std::str::FromStr;
use std::{fmt, io, marker, mem};
pub struct MappedLines<T: FromStr, R: Read> {
exit_code_on_fail: i32,
lines: Lines<BufReader<R>>,
_marker: marker::PhantomData<T>,
}
impl<T: FromStr, R: Read> Iterator for MappedLines<T, R>
where
<T as FromStr>::Err: fmt::Debug,
{
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
self.lines
.next()
.map(|line| line.or_exit_with(self.exit_code_on_fail))
.map(|line| line.parse::<T>())
.map(|record| record.or_exit_with(self.exit_code_on_fail))
}
}
pub trait WithReadLines<R: Read> {
fn read_lines<T: FromStr>(self, exit_code_on_fail: i32) -> MappedLines<T, R>;
}
impl WithReadLines<File> for File {
fn read_lines<T: FromStr>(self, exit_code_on_fail: i32) -> MappedLines<T, File> {
MappedLines {
exit_code_on_fail,
lines: BufReader::new(self).lines(),
_marker: Default::default(),
}
}
}
impl WithReadLines<File> for io::Result<File> {
fn read_lines<T: FromStr>(self, exit_code_on_fail: i32) -> MappedLines<T, File> {
self.or_exit_with(exit_code_on_fail)
.read_lines(exit_code_on_fail)
}
}
pub trait WithAsRecords {
fn as_records<T: FromStr>(&self) -> Result<Vec<T>, <T as FromStr>::Err>;
}
impl<'a> WithAsRecords for Vec<&'a str> {
fn as_records<T: FromStr>(&self) -> Result<Vec<T>, <T as FromStr>::Err> {
let mut records = Vec::new();
for line in self {
records.push(line.parse::<T>()?);
}
Ok(records)
}
}
pub trait MultilineFromStr {
type Err;
fn new() -> Self;
fn indicates_new_record(&self, line: &str) -> bool;
fn parse(&mut self, line: &str) -> Result<(), Self::Err>;
}
pub struct MappedMultiLines<T: MultilineFromStr, R: Read> {
exit_code_on_fail: i32,
lines: Lines<BufReader<R>>,
current: T,
exhausted: bool,
}
impl<T: MultilineFromStr, R: Read> Iterator for MappedMultiLines<T, R>
where
<T as MultilineFromStr>::Err: fmt::Debug,
{
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
if self.exhausted {
None
} else {
let mut record = mem::replace(&mut self.current, T::new());
self.exhausted = true;
while let Some(line) = self.lines.next() {
let line = line.or_exit_with(self.exit_code_on_fail);
if self.current.indicates_new_record(&line) {
self.exhausted = false;
self.current
.parse(&line)
.or_exit_with(self.exit_code_on_fail);
break;
}
record.parse(&line).or_exit_with(self.exit_code_on_fail);
}
Some(record)
}
}
}
pub trait WithReadMultiLines<R: Read> {
fn read_multi_lines<T: MultilineFromStr>(
self,
exit_code_on_fail: i32,
) -> MappedMultiLines<T, R>;
}
impl WithReadMultiLines<File> for File {
fn read_multi_lines<T: MultilineFromStr>(
self,
exit_code_on_fail: i32,
) -> MappedMultiLines<T, File> {
MappedMultiLines {
exit_code_on_fail,
lines: BufReader::new(self).lines(),
current: T::new(),
exhausted: false,
}
}
}
impl WithReadMultiLines<File> for io::Result<File> {
fn read_multi_lines<T: MultilineFromStr>(
self,
exit_code_on_fail: i32,
) -> MappedMultiLines<T, File> {
self.or_exit_with(exit_code_on_fail)
.read_multi_lines(exit_code_on_fail)
}
}
pub trait WithAsMultilineRecords {
fn as_multiline_records<T: MultilineFromStr>(&self) -> Result<Vec<T>, <T as MultilineFromStr>::Err>;
}
impl<'a> WithAsMultilineRecords for Vec<&'a str> {
fn as_multiline_records<T: MultilineFromStr>(&self) -> Result<Vec<T>, <T as MultilineFromStr>::Err> {
let mut records = Vec::new();
let mut record = T::new();
for line in self {
if record.indicates_new_record(line) {
records.push(record);
record = T::new();
}
record.parse(line)?;
}
records.push(record);
Ok(records)
}
}