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use std::mem;
use std::str::FromStr;
use combine::easy::Error;
use combine::error::StreamError;
use format::{Displayable, Formatter};
use position::Pos;
use tokenizer::Token;
/// Generic string value
///
/// It may consist of strings and variable references
///
/// Some string parts might originally be escaped or quoted. We get rid of
/// quotes when parsing
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Value {
position: Pos,
pub(crate) data: Vec<Item>,
}
#[derive(Debug, Clone, PartialEq, Eq)]
pub(crate) enum Item {
Literal(String),
Variable(String),
}
impl Value {
pub(crate) fn parse<'a>(position: Pos, tok: Token<'a>)
-> Result<Value, Error<Token<'a>, Token<'a>>>
{
Value::parse_str(position, tok.value)
}
pub(crate) fn parse_str<'a>(position: Pos, token: &str)
-> Result<Value, Error<Token<'a>, Token<'a>>>
{
let data = if token.starts_with('"') {
Value::scan_quoted('"', token)?
} else if token.starts_with("'") {
Value::scan_quoted('\'', token)?
} else {
Value::scan_raw(token)?
};
Ok(Value { position, data })
}
fn scan_raw<'a>(value: &str)
-> Result<Vec<Item>, Error<Token<'a>, Token<'a>>>
{
use self::Item::*;
let mut buf = Vec::new();
let mut chiter = value.char_indices().peekable();
let mut prev_char = ' '; // any having no special meaning
let mut cur_slice = 0;
// TODO(unquote) single and double quotes
while let Some((idx, cur_char)) = chiter.next() {
match cur_char {
_ if prev_char == '\\' => {
prev_char = ' ';
continue;
}
'$' => {
let vstart = idx + 1;
if idx != cur_slice {
buf.push(Literal(value[cur_slice..idx].to_string()));
}
let fchar = chiter.next().map(|(_, c)| c)
.ok_or_else(|| Error::unexpected_message(
"bare $ in expression"))?;
match fchar {
'{' => {
while let Some(&(_, c)) = chiter.peek() {
match c {
'a'...'z' | 'A'...'Z' | '_' | '0'...'9'
=> chiter.next(),
'}' => break,
_ => {
return Err(Error::expected("}".into()));
}
};
}
let now = chiter.peek().map(|&(idx, _)| idx)
.unwrap();
buf.push(Variable(
value[vstart+1..now].to_string()));
cur_slice = now+1;
}
'a'...'z' | 'A'...'Z' | '_' | '0'...'9' => {
while let Some(&(_, c)) = chiter.peek() {
match c {
'a'...'z' | 'A'...'Z' | '_' | '0'...'9'
=> chiter.next(),
_ => break,
};
}
let now = chiter.peek().map(|&(idx, _)| idx)
.unwrap_or(value.len());
buf.push(Variable(
value[vstart..now].to_string()));
cur_slice = now;
}
_ => {
return Err(Error::unexpected_message(
format!("variable name starts with \
bad char {:?}", fchar)));
}
}
}
_ => {}
}
prev_char = cur_char;
}
if cur_slice != value.len() {
buf.push(Literal(value[cur_slice..].to_string()));
}
Ok(buf)
}
fn scan_quoted<'a>(quote: char, value: &str)
-> Result<Vec<Item>, Error<Token<'a>, Token<'a>>>
{
use self::Item::*;
let mut buf = Vec::new();
let mut chiter = value.char_indices().peekable();
chiter.next(); // skip quote
let mut prev_char = ' '; // any having no special meaning
let mut cur_slice = String::new();
while let Some((idx, cur_char)) = chiter.next() {
match cur_char {
_ if prev_char == '\\' => {
cur_slice.push(cur_char);
continue;
}
'"' | '\'' if cur_char == quote => {
if cur_slice.len() > 0 {
buf.push(Literal(cur_slice));
}
if idx + 1 != value.len() {
// TODO(tailhook) figure out maybe this is actually a
// tokenizer error, or maybe make this cryptic message
// better
return Err(Error::unexpected_message(
"quote closes prematurely"));
}
return Ok(buf);
}
'$' => {
let vstart = idx + 1;
if cur_slice.len() > 0 {
buf.push(Literal(
mem::replace(&mut cur_slice, String::new())));
}
let fchar = chiter.next().map(|(_, c)| c)
.ok_or_else(|| Error::unexpected_message(
"bare $ in expression"))?;
match fchar {
'{' => {
unimplemented!();
}
'a'...'z' | 'A'...'Z' | '_' | '0'...'9' => {
while let Some(&(_, c)) = chiter.peek() {
match c {
'a'...'z' | 'A'...'Z' | '_' | '0'...'9'
=> chiter.next(),
_ => break,
};
}
let now = chiter.peek().map(|&(idx, _)| idx)
.ok_or_else(|| {
Error::unexpected_message("unclosed quote")
})?;
buf.push(Variable(
value[vstart..now].to_string()));
}
_ => {
return Err(Error::unexpected_message(
format!("variable name starts with \
bad char {:?}", fchar)));
}
}
}
_ => cur_slice.push(cur_char),
}
prev_char = cur_char;
}
return Err(Error::unexpected_message("unclosed quote"));
}
}
impl FromStr for Value {
type Err = String;
fn from_str(s: &str) -> Result<Value, String> {
Value::parse_str(Pos { line: 0, column: 0 }, s)
.map_err(|e| e.to_string())
}
}
impl Value {
fn has_specials(&self) -> bool {
use self::Item::*;
for item in &self.data {
match *item {
Literal(ref x) => {
for c in x.chars() {
match c {
' ' | ';' | '\r' | '\n' | '\t' | '{' | '}' => {
return true;
}
_ => {}
}
}
}
Variable(_) => {}
}
}
return false;
}
/// Replace variable references in this string with literal values
pub fn replace_vars<'a, F, S>(&mut self, mut f: F)
where F: FnMut(&str) -> Option<S>,
S: AsRef<str> + Into<String> + 'a,
{
use self::Item::*;
// TODO(tailhook) join literal blocks
for item in &mut self.data {
let new_value = match *item {
Literal(..) => continue,
Variable(ref name) => match f(name) {
Some(value) => value.into(),
None => continue,
},
};
*item = Literal(new_value);
}
}
}
fn next_alphanum(data: &Vec<Item>, index: usize) -> bool {
use self::Item::*;
data.get(index+1).and_then(|item| {
match item {
Literal(s) => Some(s),
Variable(_) => None,
}
}).and_then(|s| {
s.chars().next().map(|c| c.is_alphanumeric())
}).unwrap_or(false)
}
impl Displayable for Value {
fn display(&self, f: &mut Formatter) {
use self::Item::*;
if self.data.is_empty() || self.has_specials() {
f.write("\"");
for (index, item) in self.data.iter().enumerate() {
match *item {
// TODO(tailhook) escape special chars
Literal(ref v) => f.write(v),
Variable(ref v) if next_alphanum(&self.data, index) => {
f.write("${");
f.write(v);
f.write("}");
}
Variable(ref v) => {
f.write("$");
f.write(v);
}
}
}
f.write("\"");
} else {
for (index, item) in self.data.iter().enumerate() {
match *item {
Literal(ref v) => f.write(v),
Variable(ref v) if next_alphanum(&self.data, index) => {
f.write("${");
f.write(v);
f.write("}");
}
Variable(ref v) => {
f.write("$");
f.write(v);
}
}
}
}
}
}