use std::collections::HashMap;
use std::ops::{Deref, DerefMut};
use std::path::PathBuf;
use std::time::SystemTime;
use handlebars::{Handlebars, TemplateError};
use crate::functions::add_helpers;
#[derive(Debug)]
pub struct ReloadableHandlebars {
handlebars: Handlebars<'static>,
files: HashMap<&'static str, (PathBuf, Option<SystemTime>)>,
}
impl ReloadableHandlebars {
#[inline]
pub fn new() -> ReloadableHandlebars {
let mut handlebars = Handlebars::new();
add_helpers(&mut handlebars);
ReloadableHandlebars {
handlebars,
files: HashMap::new(),
}
}
#[inline]
pub fn register_template_file<P: Into<PathBuf>>(
&mut self,
name: &'static str,
file_path: P,
) -> Result<(), Box<TemplateError>> {
let file_path = file_path.into();
let metadata =
file_path.metadata().map_err(|err| TemplateError::from((err, String::from(name))))?;
let mtime = metadata.modified().ok();
self.handlebars.register_template_file(name, &file_path)?;
self.files.insert(name, (file_path, mtime));
Ok(())
}
#[inline]
pub fn unregister_template_file<S: AsRef<str>>(&mut self, name: S) -> Option<PathBuf> {
let name = name.as_ref();
match self.files.remove(name) {
Some((file_path, _)) => {
self.handlebars.unregister_template(name);
Some(file_path)
}
None => None,
}
}
#[inline]
pub fn reload_if_needed(&mut self) -> Result<(), Box<TemplateError>> {
for (&name, (file_path, mtime)) in &mut self.files {
let metadata = file_path
.metadata()
.map_err(|err| TemplateError::from((err, String::from(name))))?;
let (reload, new_mtime) = match mtime {
Some(mtime) => {
match metadata.modified() {
Ok(new_mtime) => (new_mtime > *mtime, Some(new_mtime)),
Err(_) => (true, None),
}
}
None => {
match metadata.modified() {
Ok(new_mtime) => (true, Some(new_mtime)),
Err(_) => (true, None),
}
}
};
if reload {
self.handlebars.register_template_file(name, &file_path)?;
*mtime = new_mtime;
}
}
Ok(())
}
}
impl Default for ReloadableHandlebars {
#[inline]
fn default() -> Self {
ReloadableHandlebars::new()
}
}
impl Deref for ReloadableHandlebars {
type Target = Handlebars<'static>;
#[inline]
fn deref(&self) -> &Self::Target {
&self.handlebars
}
}
impl DerefMut for ReloadableHandlebars {
#[inline]
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.handlebars
}
}