ucg/src/build/assets.rs

85 lines
2.6 KiB
Rust

// Copyright 2017 Jeremy Wall <jeremy@marzhillstudios.com>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//! The asset cache for the ucg compiler.
use std::collections::HashMap;
use std::io;
use std::path::PathBuf;
use std::rc::Rc;
use std::result;
use super::Val;
pub type Result<T> = result::Result<T, io::Error>;
/// Defines the cach interface for a UCG build. It has functions to retrieve
/// An asset for a referenced ucg file if it exists as well as to stash
/// an asset for a built ucg file.
///
/// All methods with a path do path canonicalization. As a result the path
/// is expected to exist on the filesystem. If the path does not exist on
/// the local filesystem then the Cache may return an error.
pub trait Cache {
fn has_path(&self, path: &PathBuf) -> Result<bool>;
fn get(&self, path: &PathBuf) -> Result<Option<Rc<Val>>>;
fn stash(&mut self, path: PathBuf, asset: Rc<Val>, modkey: u64) -> Result<()>;
fn evict(&mut self, path: &PathBuf) -> Result<()>;
fn check_mod_key(&self, path: &PathBuf, modkey: u64) -> Result<bool>;
}
pub struct MemoryCache {
map: HashMap<PathBuf, Rc<Val>>,
mod_key_map: HashMap<PathBuf, u64>,
}
impl MemoryCache {
pub fn new() -> Self {
MemoryCache {
map: HashMap::new(),
mod_key_map: HashMap::new(),
}
}
}
impl Cache for MemoryCache {
fn has_path(&self, path: &PathBuf) -> Result<bool> {
Ok(self.map.contains_key(path))
}
fn get(&self, path: &PathBuf) -> Result<Option<Rc<Val>>> {
Ok(self.map.get(path).map(|v| v.clone()))
}
fn stash(&mut self, path: PathBuf, asset: Rc<Val>, modkey: u64) -> Result<()> {
self.map.insert(path.clone(), asset);
self.mod_key_map.insert(path, modkey);
Ok(())
}
fn evict(&mut self, path: &PathBuf) -> Result<()> {
self.map.remove(path);
self.mod_key_map.remove(path);
Ok(())
}
fn check_mod_key(&self, path: &PathBuf, modkey: u64) -> Result<bool> {
Ok(self
.mod_key_map
.get(path)
.map(|v| *v == modkey)
.unwrap_or(true))
}
}