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use crate::error::Error;
use crate::expr::*;
use dhall_core::*;
use quick_error::quick_error;
use std::fs::File;
use std::io::Read;
use std::path::Path;
use std::path::PathBuf;
quick_error! {
#[derive(Debug)]
pub enum ImportError {
Recursive(import: Import, err: Box<Error>) {}
UnexpectedImport(import: Import) {}
}
}
/// A root from which to resolve relative imports.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum ImportRoot {
LocalDir(PathBuf),
}
fn resolve_import(
import: &Import,
root: &ImportRoot,
) -> Result<Resolved, ImportError> {
use self::ImportRoot::*;
use dhall_core::FilePrefix::*;
use dhall_core::ImportLocation::*;
let cwd = match root {
LocalDir(cwd) => cwd,
};
match &import.location_hashed.location {
Local(prefix, path) => {
let path = match prefix {
// TODO: fail gracefully
Parent => cwd.parent().unwrap().join(path),
Here => cwd.join(path),
_ => unimplemented!("{:?}", import),
};
Ok(load_import(&path).map_err(|e| {
ImportError::Recursive(import.clone(), Box::new(e))
})?)
}
_ => unimplemented!("{:?}", import),
}
}
fn load_import(f: &Path) -> Result<Resolved, Error> {
Ok(Parsed::parse_file(f)?.resolve()?)
}
fn resolve_expr(
Parsed(expr, root): Parsed,
allow_imports: bool,
) -> Result<Resolved, ImportError> {
let resolve = |import: &Import| -> Result<SubExpr<X, X>, ImportError> {
if allow_imports {
let expr = resolve_import(import, &root)?;
Ok(expr.0)
} else {
Err(ImportError::UnexpectedImport(import.clone()))
}
};
let expr = expr.as_ref().traverse_embed(&resolve)?;
Ok(Resolved(expr.squash_embed()))
}
impl Parsed {
pub fn parse_file(f: &Path) -> Result<Parsed, Error> {
let mut buffer = String::new();
File::open(f)?.read_to_string(&mut buffer)?;
let expr = parse_expr(&*buffer)?;
let root = ImportRoot::LocalDir(f.parent().unwrap().to_owned());
Ok(Parsed(expr, root))
}
pub fn parse_str(s: &str) -> Result<Parsed, Error> {
let expr = parse_expr(s)?;
let root = ImportRoot::LocalDir(std::env::current_dir()?);
Ok(Parsed(expr, root))
}
pub fn parse_binary_file(f: &Path) -> Result<Parsed, Error> {
let mut buffer = Vec::new();
File::open(f)?.read_to_end(&mut buffer)?;
let expr = crate::binary::decode(&buffer)?;
let root = ImportRoot::LocalDir(f.parent().unwrap().to_owned());
Ok(Parsed(expr, root))
}
pub fn resolve(self) -> Result<Resolved, ImportError> {
crate::imports::resolve_expr(self, true)
}
pub fn skip_resolve(self) -> Result<Resolved, ImportError> {
crate::imports::resolve_expr(self, false)
}
}
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