build: prebuild binary_cache and assetstorage canister asset archives

assets.nix

@@ -2,19 +2,27 @@
 , bootstrap-js ? import ./nix/agent-js/bootstrap-js.nix { inherit pkgs; }
 , distributed-canisters ? import ./distributed-canisters.nix { inherit pkgs; }
 }:
+let
+  looseBinaryCache = pkgs.runCommandNoCCLocal "loose-binary-cache" {} ''
+    mkdir -p $out
+
+    cp ${pkgs.dfinity.ic-replica}/bin/replica $out
+    cp ${pkgs.dfinity.ic-starter}/bin/ic-starter $out
+    cp -R ${pkgs.motoko.base-src} $out/base
+    cp ${pkgs.motoko.mo-doc}/bin/mo-doc $out
+    cp ${pkgs.motoko.mo-ide}/bin/mo-ide $out
+    cp ${pkgs.motoko.moc}/bin/moc $out
+
+    # Install bootstrap
+    mkdir $out/bootstrap
+    cp -R ${bootstrap-js.dist}/* $out/bootstrap/
+  '';
+in
 pkgs.runCommandNoCCLocal "assets" {} ''
   mkdir -p $out
 
-  cp ${pkgs.dfinity.ic-replica}/bin/replica $out
-  cp ${pkgs.dfinity.ic-starter}/bin/ic-starter $out
-  cp -R ${pkgs.motoko.base-src} $out/base
-  cp ${pkgs.motoko.mo-doc}/bin/mo-doc $out
-  cp ${pkgs.motoko.mo-ide}/bin/mo-ide $out
-  cp ${pkgs.motoko.moc}/bin/moc $out
+  tar -czf $out/binary_cache.tgz -C ${looseBinaryCache}/ .
 
-  # Install bootstrap
-  mkdir $out/bootstrap
-  cp -R ${bootstrap-js.dist}/* $out/bootstrap/
+  tar -czf $out/assetstorage_canister.tgz -C ${distributed-canisters}/assetstorage/ .
 
-  cp -R ${distributed-canisters} $out/canisters
 ''

src/dfx/assets/build.rs

@@ -5,14 +5,37 @@ use std::fs::File;
 use std::io::Write;
 use std::path::Path;
 
-fn add_assets(fn_name: &str, f: &mut File, path: &str) {
+fn add_asset_archive(fn_name: &str, f: &mut File) {
+    let filename_tgz = format!("{}.tgz", fn_name);
+
+    let path = env::var("DFX_ASSETS").expect("Cannot find DFX_ASSETS");
+    let prebuilt_file = Path::new(&path).join(&filename_tgz);
+
+    let out_dir = env::var("OUT_DIR").unwrap();
+    let tgz_path = Path::new(&out_dir).join(&filename_tgz);
+
+    if tgz_path.exists() {
+        // This avoids PermissionDenied errors.
+        std::fs::remove_file(&tgz_path).unwrap();
+    }
+    std::fs::copy(prebuilt_file, tgz_path).unwrap();
+
+    write_archive_accessor(fn_name, f);
+}
+
+fn add_assets_from_directory(fn_name: &str, f: &mut File, path: &str) {
     let out_dir = env::var("OUT_DIR").unwrap();
     let tgz_path = Path::new(&out_dir).join(format!("{}.tgz", fn_name));
+
     let tar_gz = File::create(&tgz_path).unwrap();
     let enc = GzEncoder::new(tar_gz, Compression::default());
     let mut tar = tar::Builder::new(enc);
     tar.append_dir_all("", path).unwrap();
 
+    write_archive_accessor(fn_name, f);
+}
+
+fn write_archive_accessor(fn_name: &str, f: &mut File) {
     f.write_all(
         format!(
             "
@@ -32,28 +55,6 @@ fn add_assets(fn_name: &str, f: &mut File, path: &str) {
     .unwrap();
 }
 
-fn add_optional_assets(fn_name: &str, f: &mut File, path: &str) {
-    if Path::new(path).exists() {
-        add_assets(fn_name, f, path);
-    } else {
-        f.write_all(
-            format!(
-                "
-            pub fn {fn_name}() -> Result<Archive<GzDecoder<Cursor<Vec<u8>>>>> {{
-                Err(std::io::Error::new(
-                    std::io::ErrorKind::NotFound,
-                    \"{fn_name} is not available during this build phase.\",
-                ))
-            }}
-        ",
-                fn_name = fn_name,
-            )
-            .as_bytes(),
-        )
-        .unwrap();
-    }
-}
-
 fn get_git_hash() -> Option<String> {
     use std::process::Command;
 
@@ -82,13 +83,11 @@ fn main() {
     )
     .unwrap();
 
-    let path = env::var("DFX_ASSETS").expect("Cannot find DFX_ASSETS");
-    add_assets("binary_cache", &mut f, &path);
-    let assetstorage_canister_path = path + &String::from("/canisters/assetstorage");
-    add_optional_assets("assetstorage_canister", &mut f, &assetstorage_canister_path);
-    add_assets("language_bindings", &mut f, "assets/language_bindings");
-    add_assets("new_project_files", &mut f, "assets/new_project_files");
-    add_assets(
+    add_asset_archive("binary_cache", &mut f);
+    add_asset_archive("assetstorage_canister", &mut f);
+    add_assets_from_directory("language_bindings", &mut f, "assets/language_bindings");
+    add_assets_from_directory("new_project_files", &mut f, "assets/new_project_files");
+    add_assets_from_directory(
         "new_project_node_files",
         &mut f,
         "assets/new_project_node_files",