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use crate::StmtData;
use std::io::{
BufRead,
BufReader,
Cursor,
Read,
Seek,
SeekFrom,
};
pub struct MultiStatement<R> {
content: BufReader<R>,
}
impl<R> MultiStatement<R>
where
R: Read + Send + Sync + Seek,
{
pub fn from_reader(reader: R) -> Self {
MultiStatement {
content: BufReader::new(reader),
}
}
pub fn statement_iter(self) -> StatementIter<R> {
StatementIter {
content: self.content,
}
}
}
pub struct StatementIter<R> {
content: BufReader<R>,
}
impl<R> StatementIter<R>
where
R: Read + Send + Sync + Seek,
{
pub fn new(content: BufReader<R>) -> Self {
StatementIter { content }
}
fn ignore_whitespace(&mut self) {
let mut buffer = String::new();
while let Ok(n) = self.content.read_line(&mut buffer) {
if buffer.trim().is_empty() {
} else {
self.content
.seek(SeekFrom::Current(-(n as i64)))
.expect("must seek");
break;
}
if n == 0 {
break;
}
}
}
}
impl<R> Iterator for StatementIter<R>
where
R: Read + Send + Sync + Seek,
{
type Item = StmtData<Cursor<Vec<u8>>>;
fn next(&mut self) -> Option<Self::Item> {
self.ignore_whitespace();
let mut buffer = vec![];
while let Ok(n) = self.content.read_until(b'\n', &mut buffer) {
let last_char = buffer.iter().last();
if (n == 1 && last_char == Some(&b'\n')) || n == 0 {
if !buffer.is_empty() {
let stmt = StmtData::from_reader(Cursor::new(buffer))
.expect("must not error");
return Some(stmt);
} else {
return None;
}
}
if n == 0 {
break;
}
}
None
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::ast::*;
#[test]
fn test_multi_statement() {
let data = r#"PUT /+category{*category_id:s32,name:text,description:text?,slug:text?,topic:i32?,created_at:utc,updated:utc}
1,Staff,staff,Private categories for staff discussion. Topics are only visible to admin and moderators
2,Technology,tecnology,Anything related to technology
PUT /+topic{*topic:s32,title:text,excerpt:text?,created_at:utc(now()),updated_at:utc?}
1,About Euphorum,1
3,Topic3,3
2,Welcome to Euphorum,2"#;
let ms = MultiStatement::from_reader(Cursor::new(data.as_bytes()));
let mut iter = ms.statement_iter();
let stmt1 = iter.next().expect("must have a next");
if let Statement::Create(create_cat) = stmt1.statement() {
println!("create1: {}", create_cat);
}
let data1 = stmt1.rows_iter().expect("must have csv rows");
let all_data1 = data1.collect::<Vec<_>>();
assert_eq!(all_data1.len(), 2);
let stmt2 = iter.next().expect("must have a next");
if let Statement::Create(create_topic) = stmt2.statement() {
println!("create2: {}", create_topic);
}
let data2 = stmt2.rows_iter().expect("must have csv rows");
let all_data2 = dbg!(data2.collect::<Vec<_>>());
assert_eq!(all_data2.len(), 3);
}
#[test]
fn test_multi_statement_with_multiple_empty_lines() {
let data = r#"
PUT /+category{*category_id:s32,name:text,description:text?,slug:text?,topic:i32?,created_at:utc,updated:utc}
1,Staff,staff,Private categories for staff discussion. Topics are only visible to admin and moderators
2,Technology,tecnology,Anything related to technology
PUT /+topic{*topic:s32,title:text,excerpt:text?,created_at:utc(now()),updated_at:utc?}
1,About Euphorum,1
3,Topic3,3
2,Welcome to Euphorum,2"#;
let ms = MultiStatement::from_reader(Cursor::new(data.as_bytes()));
let mut iter = ms.statement_iter();
let stmt1 = iter.next().expect("must have a next");
if let Statement::Create(create_cat) = stmt1.statement() {
println!("create1: {}", create_cat);
}
let data1 = stmt1.rows_iter().expect("must have csv rows");
let all_data1 = data1.collect::<Vec<_>>();
assert_eq!(all_data1.len(), 2);
let stmt2 = iter.next().expect("must have a next");
if let Statement::Create(create_topic) = stmt2.statement() {
println!("create2: {}", create_topic);
}
let data2 = stmt2.rows_iter().expect("must have csv rows");
let all_data2 = dbg!(data2.collect::<Vec<_>>());
assert_eq!(all_data2.len(), 3);
}
}