mod source_id;
mod span;
mod to_string;
use std::collections::{HashMap, HashSet};
pub use source_id::SourceId;
pub use span::Span;
pub use to_string::{Counter, StringWithSourceMap, ToString};
const BASE64_ALPHABET: &'static [u8; 64] =
b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
fn vlq_encode_integer_to_buffer(buf: &mut String, mut value: isize) {
if value.is_negative() {
value = (-value << 1) | 1;
} else {
value <<= 1;
};
loop {
let mut clamped = value & 31;
value >>= 5;
if value > 0 {
clamped |= 32;
}
buf.push(BASE64_ALPHABET[clamped as usize] as char);
if value <= 0 {
break;
}
}
}
#[derive(Debug)]
struct SourceMapping {
pub(crate) on_output_line: usize,
pub(crate) on_output_column: usize,
pub(crate) source_byte_start: usize,
pub(crate) source_byte_end: usize,
pub(crate) from_source: SourceId,
}
#[derive(Debug)]
enum MappingOrBreak {
Mapping(SourceMapping),
Break,
}
pub struct SourceMapBuilder {
current_output_line: usize,
current_output_column: usize,
#[allow(dead_code)]
last_output_line: Option<usize>,
last_output_column: usize,
mappings: Vec<MappingOrBreak>,
used_sources: HashSet<SourceId>,
}
impl SourceMapBuilder {
pub fn new() -> SourceMapBuilder {
SourceMapBuilder {
current_output_line: 0,
last_output_line: None,
current_output_column: 0,
last_output_column: 0,
mappings: Vec::new(),
used_sources: HashSet::new(),
}
}
pub fn add_new_line(&mut self) {
self.current_output_line += 1;
self.mappings.push(MappingOrBreak::Break);
self.current_output_column = 0;
self.last_output_column = 0;
}
pub fn add_to_column(&mut self, length: usize) {
self.current_output_column += length;
}
pub fn add_mapping(&mut self, source_position: &Span) {
let Span {
start: source_byte_start,
end: source_byte_end,
source_id: from_source,
} = source_position;
self.used_sources.insert(*from_source);
self.mappings.push(MappingOrBreak::Mapping(SourceMapping {
from_source: *from_source,
source_byte_start: *source_byte_start,
source_byte_end: *source_byte_end,
on_output_line: self.current_output_line,
on_output_column: self.current_output_column,
}));
}
pub fn build(self) -> String {
let mut source_line_splits = HashMap::<SourceId, Vec<_>>::new();
let mut source_ids = Vec::<SourceId>::new();
let mut source_names = Vec::<String>::new();
let mut source_contents = Vec::<String>::new();
for source_id in self.used_sources {
let (source_path, source_content) = source_id.get_file().unwrap();
let source_content = source_content.replace('\r', "");
let line_splits = source_content
.char_indices()
.filter_map(|(idx, chr)| (chr == '\n').then(|| idx))
.collect::<Vec<_>>();
source_line_splits.insert(source_id, line_splits);
source_ids.push(source_id);
source_names.push(format!("\"{}\"", source_path.display()).replace('\\', "/"));
source_contents.push(format!("\"{}\"", source_content.replace('\n', "\\n")));
}
let mut source_map_mappings_field = String::new();
let mut last_was_break = None::<bool>;
let mut last_mapped_source_line = 0;
let mut last_mapped_source_column = 0;
let mut last_mapped_output_column = 0;
for mapping in self.mappings {
match mapping {
MappingOrBreak::Mapping(mapping) => {
let SourceMapping {
on_output_column,
source_byte_start,
on_output_line: _,
source_byte_end: _,
from_source,
} = mapping;
if !last_was_break.unwrap_or(true) {
source_map_mappings_field.push(',');
}
let output_column =
on_output_column as isize - last_mapped_output_column as isize;
vlq_encode_integer_to_buffer(&mut source_map_mappings_field, output_column);
last_mapped_output_column = on_output_column;
let idx = source_ids
.iter()
.position(|sid| *sid == from_source)
.unwrap();
vlq_encode_integer_to_buffer(&mut source_map_mappings_field, idx as isize);
let line_splits_for_this_file = source_line_splits.get(&from_source).unwrap();
let (line, column) = if source_byte_start < line_splits_for_this_file[0] {
(0, source_byte_start)
} else {
line_splits_for_this_file
.windows(2)
.enumerate()
.find_map(|(line, window)| {
if let [floor, ceil] = window {
(*floor <= source_byte_start && source_byte_start <= *ceil)
.then(|| (line + 1, source_byte_start - floor - 1))
} else {
unreachable!()
}
})
.unwrap()
};
vlq_encode_integer_to_buffer(
&mut source_map_mappings_field,
line as isize - last_mapped_source_line as isize,
);
last_mapped_source_line = line;
vlq_encode_integer_to_buffer(
&mut source_map_mappings_field,
column as isize - last_mapped_source_column as isize,
);
last_mapped_source_column = column;
last_was_break = Some(false);
}
MappingOrBreak::Break => {
source_map_mappings_field.push(';');
last_was_break = Some(true);
last_mapped_output_column = 0;
}
}
}
format!(
r#"{{"version":3,"sourceRoot":"","sources":[{}],"sourcesContent":[{}],"names":[],"mappings":"{}"}}"#,
source_names
.into_iter()
.reduce(quote_and_comma_delimiter)
.unwrap(),
source_contents
.into_iter()
.reduce(quote_and_comma_delimiter)
.unwrap(),
source_map_mappings_field
)
}
}
fn quote_and_comma_delimiter(mut a: String, b: impl AsRef<str>) -> String {
a.push_str(", ");
a.push_str(b.as_ref());
a
}
#[cfg(test)]
mod source_map_tests {
use super::vlq_encode_integer_to_buffer;
fn vlq_encode_integer(value: isize) -> String {
let mut buf = String::new();
vlq_encode_integer_to_buffer(&mut buf, value);
buf
}
#[test]
fn vlq_encoder() {
assert_eq!(vlq_encode_integer(0), "A");
assert_eq!(vlq_encode_integer(1), "C");
assert_eq!(vlq_encode_integer(-1), "D");
assert_eq!(vlq_encode_integer(123), "2H");
assert_eq!(vlq_encode_integer(123456789), "qxmvrH");
}
}