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use crate::error::Error;
use crate::expr::*;
use dhall_syntax::*;
use std::collections::HashMap;
use std::fs::File;
use std::io::Read;
use std::path::Path;
use std::path::PathBuf;
#[derive(Debug)]
pub enum ImportError {
Recursive(Import, Box<Error>),
UnexpectedImport(Import),
ImportCycle(ImportStack, Import),
}
/// A root from which to resolve relative imports.
#[derive(Debug, Clone, PartialEq, Eq)]
pub enum ImportRoot {
LocalDir(PathBuf),
}
type ImportCache = HashMap<Import, Normalized>;
type ImportStack = Vec<Import>;
fn resolve_import(
import: &Import,
root: &ImportRoot,
import_cache: &mut ImportCache,
import_stack: &ImportStack,
) -> Result<Normalized, ImportError> {
use self::ImportRoot::*;
use dhall_syntax::FilePrefix::*;
use dhall_syntax::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, import_cache, import_stack).map_err(|e| {
ImportError::Recursive(import.clone(), Box::new(e))
})?)
}
_ => unimplemented!("{:?}", import),
}
}
fn load_import(
f: &Path,
import_cache: &mut ImportCache,
import_stack: &ImportStack,
) -> Result<Normalized, Error> {
Ok(
do_resolve_expr(Parsed::parse_file(f)?, import_cache, import_stack)?
.typecheck()?
.normalize(),
)
}
fn do_resolve_expr(
Parsed(expr, root): Parsed,
import_cache: &mut ImportCache,
import_stack: &ImportStack,
) -> Result<Resolved, ImportError> {
let resolve = |import: &Import| -> Result<Normalized, ImportError> {
if import_stack.contains(import) {
return Err(ImportError::ImportCycle(
import_stack.clone(),
import.clone(),
));
}
match import_cache.get(import) {
Some(expr) => Ok(expr.clone()),
None => {
// Copy the import stack and push the current import
let mut import_stack = import_stack.clone();
import_stack.push(import.clone());
// Resolve the import recursively
let expr =
resolve_import(import, &root, import_cache, &import_stack)?;
// Add the import to the cache
import_cache.insert(import.clone(), expr.clone());
Ok(expr)
}
}
};
let expr = expr.traverse_embed(resolve)?;
Ok(Resolved(expr))
}
fn skip_resolve_expr(
Parsed(expr, _root): Parsed,
) -> Result<Resolved, ImportError> {
let resolve = |import: &Import| -> Result<Normalized, ImportError> {
Err(ImportError::UnexpectedImport(import.clone()))
};
let expr = expr.traverse_embed(resolve)?;
Ok(Resolved(expr))
}
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.unnote().note_absurd(), 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))
}
#[allow(dead_code)]
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.note_absurd(), root))
}
pub fn resolve(self) -> Result<Resolved, ImportError> {
crate::imports::do_resolve_expr(self, &mut HashMap::new(), &Vec::new())
}
#[allow(dead_code)]
pub fn skip_resolve(self) -> Result<Resolved, ImportError> {
crate::imports::skip_resolve_expr(self)
}
}
#[cfg(test)]
mod spec_tests {
#![rustfmt::skip]
macro_rules! import_success {
($name:ident, $path:expr) => {
make_spec_test!(Import, Success, $name, $path);
};
}
// macro_rules! import_failure {
// ($name:ident, $path:expr) => {
// make_spec_test!(Import, Failure, $name, $path);
// };
// }
// import_success!(success_alternativeEnvNatural, "alternativeEnvNatural");
// import_success!(success_alternativeEnvSimple, "alternativeEnvSimple");
// import_success!(success_alternativeNatural, "alternativeNatural");
// import_success!(success_asText, "asText");
import_success!(success_fieldOrder, "fieldOrder");
// import_failure!(failure_alternativeEnv, "alternativeEnv");
// import_failure!(failure_alternativeEnvMissing, "alternativeEnvMissing");
// import_failure!(failure_cycle, "cycle");
// import_failure!(failure_missing, "missing");
// import_failure!(failure_referentiallyInsane, "referentiallyInsane");
}
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