Refactor: Use trait constraints instead of a trait object for our assets cache.

src/build/format.rs

@@ -19,6 +19,7 @@ use std::error::Error;
 use std::str::Chars;
 
 use crate::ast::*;
+use crate::build::assets;
 use crate::build::{FileBuilder, Val};
 use crate::error;
 
@@ -85,13 +86,19 @@ impl<V: Into<String> + Clone> FormatRenderer for SimpleFormatter<V> {
     }
 }
 
-pub struct ExpressionFormatter<'a> {
+pub struct ExpressionFormatter<'a, C>
+where
+    C: assets::Cache,
+{
     tmpl: String,
-    builder: RefCell<FileBuilder<'a>>,
+    builder: RefCell<FileBuilder<'a, C>>,
 }
 
-impl<'a> ExpressionFormatter<'a> {
+impl<'a, C> ExpressionFormatter<'a, C>
-    pub fn new<S: Into<String>>(tmpl: S, builder: FileBuilder<'a>) -> Self {
+where
+    C: assets::Cache,
+{
+    pub fn new<S: Into<String>>(tmpl: S, builder: FileBuilder<'a, C>) -> Self {
         ExpressionFormatter {
             tmpl: tmpl.into(),
             builder: RefCell::new(builder),
@@ -100,7 +107,7 @@ impl<'a> ExpressionFormatter<'a> {
 
     fn consume_expr(
         &self,
-        builder: &mut FileBuilder,
+        builder: &mut FileBuilder<'a, C>,
         iter: &mut Chars,
         pos: &Position,
     ) -> Result<Val, Box<dyn Error>> {
@@ -176,7 +183,10 @@ impl<'a> ExpressionFormatter<'a> {
     }
 }
 
-impl<'a> FormatRenderer for ExpressionFormatter<'a> {
+impl<'a, C> FormatRenderer for ExpressionFormatter<'a, C>
+where
+    C: assets::Cache,
+{
     fn render(&self, pos: &Position) -> Result<String, Box<dyn Error>> {
         let mut buf = String::new();
         let mut should_escape = false;

src/build/mod.rs

@@ -53,11 +53,14 @@ enum ProcessingOpType {
 
 impl FuncDef {
     /// Expands a ucg function using the given arguments into a new Val.
-    pub fn eval(
+    pub fn eval<C>(
         &self,
-        parent_builder: &FileBuilder,
+        parent_builder: &FileBuilder<C>,
         mut args: Vec<Rc<Val>>,
-    ) -> Result<Rc<Val>, Box<dyn Error>> {
+    ) -> Result<Rc<Val>, Box<dyn Error>>
+    where
+        C: assets::Cache,
+    {
         // Error conditions. If the args don't match the length and types of the argdefs then this is
         // func call error.
         if args.len() > self.argdefs.len() {
@@ -98,7 +101,10 @@ pub struct AssertCollector {
 }
 
 /// Builder handles building ucg code for a single file.
-pub struct FileBuilder<'a> {
+pub struct FileBuilder<'a, C>
+where
+    C: assets::Cache,
+{
     working_dir: PathBuf,
     std: Rc<HashMap<String, &'static str>>,
     import_path: &'a Vec<PathBuf>,
@@ -117,7 +123,7 @@ pub struct FileBuilder<'a> {
     // are keyed by the canonicalized import path. This acts as a cache
     // so multiple imports of the same file don't have to be parsed
     // multiple times.
-    assets: Rc<RefCell<assets::Cache>>,
+    assets: Rc<RefCell<C>>,
     pub is_module: bool,
     pub last: Option<Rc<Val>>,
     pub out_lock: Option<(String, Rc<Val>)>,
@@ -141,12 +147,15 @@ macro_rules! eval_binary_expr {
     };
 }
 
-impl<'a> FileBuilder<'a> {
+impl<'a, C> FileBuilder<'a, C>
+where
+    C: assets::Cache,
+{
     /// Constructs a new Builder.
     pub fn new<P: Into<PathBuf>>(
         working_dir: P,
         import_paths: &'a Vec<PathBuf>,
-        cache: Rc<RefCell<assets::Cache>>,
+        cache: Rc<RefCell<C>>,
     ) -> Self {
         let env_vars: Vec<(String, String)> = env::vars().collect();
         let scope = scope::Scope::new(Rc::new(Val::Env(env_vars)));

src/build/test.rs

@@ -11,6 +11,7 @@
 //  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.
+use super::assets;
 use super::assets::MemoryCache;
 use super::{FileBuilder, SelectDef, Val};
 use crate::ast::*;
@@ -19,7 +20,10 @@ use std;
 use std::cell::RefCell;
 use std::rc::Rc;
 
-fn test_expr_to_val(mut cases: Vec<(Expression, Val)>, b: FileBuilder) {
+fn test_expr_to_val<'a, C: assets::Cache>(
+    mut cases: Vec<(Expression, Val)>,
+    b: FileBuilder<'a, C>,
+) {
     for tpl in cases.drain(0..) {
         assert_eq!(
             b.eval_expr(&tpl.0, &b.scope.spawn_child()).unwrap(),

src/main.rs

@@ -93,13 +93,13 @@ fn run_converter(c: &traits::Converter, v: Rc<Val>, f: Option<&str>) -> traits::
     c.convert(v, file.as_mut())
 }
 
-fn build_file<'a>(
+fn build_file<'a, C: Cache>(
     file: &'a str,
     validate: bool,
     strict: bool,
     import_paths: &'a Vec<PathBuf>,
-    cache: Rc<RefCell<Cache>>,
+    cache: Rc<RefCell<C>>,
-) -> Result<build::FileBuilder<'a>, Box<dyn Error>> {
+) -> Result<build::FileBuilder<'a, C>, Box<dyn Error>> {
     let mut file_path_buf = PathBuf::from(file);
     if file_path_buf.is_relative() {
         file_path_buf = std::env::current_dir()?.join(file_path_buf);
@@ -116,11 +116,11 @@ fn build_file<'a>(
     Ok(builder)
 }
 
-fn do_validate(
+fn do_validate<C: Cache>(
     file: &str,
     strict: bool,
     import_paths: &Vec<PathBuf>,
-    cache: Rc<RefCell<Cache>>,
+    cache: Rc<RefCell<C>>,
 ) -> bool {
     println!("Validating {}", file);
     match build_file(file, true, strict, import_paths, cache) {
@@ -140,11 +140,11 @@ fn do_validate(
     return true;
 }
 
-fn do_compile(
+fn do_compile<C: Cache>(
     file: &str,
     strict: bool,
     import_paths: &Vec<PathBuf>,
-    cache: Rc<RefCell<Cache>>,
+    cache: Rc<RefCell<C>>,
     registry: &ConverterRegistry,
 ) -> bool {
     println!("Building {}", file);
@@ -175,13 +175,13 @@ fn do_compile(
     }
 }
 
-fn visit_ucg_files(
+fn visit_ucg_files<C: Cache>(
     path: &Path,
     recurse: bool,
     validate: bool,
     strict: bool,
     import_paths: &Vec<PathBuf>,
-    cache: Rc<RefCell<Cache>>,
+    cache: Rc<RefCell<C>>,
     registry: &ConverterRegistry,
 ) -> Result<bool, Box<dyn Error>> {
     let our_path = String::from(path.to_string_lossy());
@@ -252,10 +252,10 @@ fn visit_ucg_files(
     Ok(result)
 }
 
-fn inspect_command(
+fn inspect_command<C: Cache>(
     matches: &clap::ArgMatches,
     import_paths: &Vec<PathBuf>,
-    cache: Rc<RefCell<Cache>>,
+    cache: Rc<RefCell<C>>,
     registry: &ConverterRegistry,
     strict: bool,
 ) {
@@ -315,10 +315,10 @@ fn inspect_command(
     }
 }
 
-fn build_command(
+fn build_command<C: Cache>(
     matches: &clap::ArgMatches,
     import_paths: &Vec<PathBuf>,
-    cache: Rc<RefCell<Cache>>,
+    cache: Rc<RefCell<C>>,
     registry: &ConverterRegistry,
     strict: bool,
 ) {
@@ -414,10 +414,10 @@ fn fmt_command(matches: &clap::ArgMatches) -> std::result::Result<(), Box<dyn Er
     Ok(())
 }
 
-fn test_command(
+fn test_command<C: Cache>(
     matches: &clap::ArgMatches,
     import_paths: &Vec<PathBuf>,
-    cache: Rc<RefCell<Cache>>,
+    cache: Rc<RefCell<C>>,
     registry: &ConverterRegistry,
     strict: bool,
 ) {
@@ -513,9 +513,9 @@ fn env_help() {
     );
 }
 
-fn do_repl(
+fn do_repl<C: Cache>(
     import_paths: &Vec<PathBuf>,
-    cache: Rc<RefCell<Cache>>,
+    cache: Rc<RefCell<C>>,
 ) -> std::result::Result<(), Box<dyn Error>> {
     let config = rustyline::Config::builder();
     let mut editor = rustyline::Editor::<()>::with_config(
@@ -580,7 +580,7 @@ fn do_repl(
     }
 }
 
-fn repl(import_paths: &Vec<PathBuf>, cache: Rc<RefCell<Cache>>) {
+fn repl<C: Cache>(import_paths: &Vec<PathBuf>, cache: Rc<RefCell<C>>) {
     if let Err(e) = do_repl(import_paths, cache) {
         eprintln!("{}", e);
         process::exit(1);
@@ -590,7 +590,7 @@ fn repl(import_paths: &Vec<PathBuf>, cache: Rc<RefCell<Cache>>) {
 fn main() {
     let mut app = do_flags();
     let app_matches = app.clone().get_matches();
-    let cache: Rc<RefCell<Cache>> = Rc::new(RefCell::new(MemoryCache::new()));
+    let cache = Rc::new(RefCell::new(MemoryCache::new()));
     let registry = ConverterRegistry::make_registry();
     let mut import_paths = Vec::new();
     if let Some(mut p) = dirs::home_dir() {