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use std::collections::VecDeque;
use pest::{iterators::Pair, Parser};
use pest_derive::Parser;
use crate::{
error::Error,
line::*,
context::*,
patch::*,
PatchResult,
};
#[derive(Parser)]
#[grammar = "../peg/patch.peg"]
pub struct PatchProcessor {
text: Vec<String>,
patch: Patch,
}
impl PatchProcessor {
pub fn converted(text: Vec<String>, patch: &str) -> PatchResult<Self> {
Ok(Self {
text,
patch: Self::convert(patch)?,
})
}
pub fn process(&self) -> PatchResult<Vec<String>> {
let mut file2_text = Vec::new();
let mut file1_ptr: usize = 0;
for context in &self.patch.contexts {
for i in file1_ptr..context.header.file1_l-1 {
file2_text.push(
self.text
.get(i)
.ok_or_else(|| Error::AbruptInput(i))?
.to_owned(),
);
}
file1_ptr = context.header.file1_l-1;
for line in &context.data {
match line {
Line::Context(ref data) => {
if self
.text
.get(file1_ptr)
.ok_or_else(|| Error::AbruptInput(file1_ptr))?
!= data
{
return Err(Error::PatchInputMismatch(file1_ptr));
}
file2_text.push(data.to_owned());
file1_ptr += 1;
}
Line::Delete(ref data) => {
if self
.text
.get(file1_ptr)
.ok_or_else(|| Error::AbruptInput(file1_ptr))?
!= data
{
return Err(Error::PatchInputMismatch(file1_ptr));
}
file1_ptr += 1;
}
Line::Insert(ref data) => {
file2_text.push(data.to_owned());
}
}
}
}
for i in file1_ptr..self.text.len() {
file2_text.push(
self.text
.get(i)
.ok_or_else(|| Error::AbruptInput(i))?
.to_owned(),
);
}
Ok(file2_text)
}
pub fn convert(patch: &str) -> PatchResult<Patch> {
let peg_patch = Self::parse(Rule::patch, patch)?
.next()
.ok_or(Error::NotFound("patch"))?;
let mut contexts = VecDeque::new();
let mut input = None;
let mut output = None;
for patch_element in peg_patch.into_inner() {
match patch_element.as_rule() {
Rule::file1_header => {
for header_element in patch_element.into_inner() {
if let Rule::path = header_element.as_rule() {
input = Some(header_element.as_span().as_str().to_owned());
}
}
}
Rule::file2_header => {
for header_element in patch_element.into_inner() {
if let Rule::path = header_element.as_rule() {
output = Some(header_element.as_span().as_str().to_owned());
}
}
}
Rule::context => {
let mut peg_context = patch_element.into_inner();
let context_header = peg_context
.next()
.ok_or(Error::NotFound("context_header"))?;
let context_header = if let Rule::context_header = context_header.as_rule() {
Self::get_context_header(context_header)?
} else {
return Err(Error::MalformedPatch(
"Context header is not at the start of a context",
));
};
let mut context = Context {
header: context_header,
data: Vec::new(),
};
for line in peg_context {
match line.as_rule() {
Rule::line_context => context
.data
.push(Line::Context(line.as_span().as_str().to_owned())),
Rule::line_deleted => context
.data
.push(Line::Delete(line.as_span().as_str().to_owned())),
Rule::line_inserted => context
.data
.push(Line::Insert(line.as_span().as_str().to_owned())),
_ => {}
}
}
contexts.push_back(context);
}
_ => {}
}
}
let input = input.ok_or_else(|| Error::NotFound("path (input)"))?;
let output = output.ok_or_else(|| Error::NotFound("path (output)"))?;
let patch = Patch {
input,
output,
contexts,
};
Ok(patch)
}
fn get_context_header(header: Pair<'_, Rule>) -> PatchResult<ContextHeader> {
let mut output = ContextHeader::default();
for header_element in header.into_inner() {
match header_element.as_rule() {
Rule::file1_l => output.file1_l = header_element.as_span().as_str().parse()?,
Rule::file1_s => output.file1_s = header_element.as_span().as_str().parse()?,
Rule::file2_l => output.file2_l = header_element.as_span().as_str().parse()?,
Rule::file2_s => output.file2_s = header_element.as_span().as_str().parse()?,
_ => {}
}
}
Ok(output)
}
}