Module: Lilac::CLI::CompiledBootModule

Defined in:
lib/lilac/cli/build/compiled_boot_module.rb

Overview

Emits the <script type="module"> boot stub for the :compiled target: it loads .mrb bytecode, boots the lilac-compiled wasm, and (in :bundle delivery) pulls the bundle's <template> elements into the live document before Lilac.start runs.

Split out of PageCompiler so the JS-string generation lives next to HtmlEmitter's markup-emitting peers rather than mixing into the per-page compile flow.

Class Method Summary collapse

Class Method Details

.mrb_chain(bundle_assets, page_local_mrb) ⇒ Object

Decide the .mrb load order for a :compiled × :bundle page's boot module. The bundle .mrb always loads first (component class definitions, no Lilac.start). The tail is either the page-local .mrb (which itself ends with Lilac.start) or the shared start-only.mrb fallback so every page's chain terminates with Lilac.start.



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# File 'lib/lilac/cli/build/compiled_boot_module.rb', line 22

def mrb_chain(bundle_assets, page_local_mrb)
  return [] unless bundle_assets

  chain = []
  chain << bundle_assets.bundle_mrb if bundle_assets.bundle_mrb
  if page_local_mrb
    chain << page_local_mrb
  elsif bundle_assets.bundle_mrb && bundle_assets.start_only_mrb
    chain << bundle_assets.start_only_mrb
  end
  chain
end

.render(mrb_filenames, package_urls: [], delivery: :inline) ⇒ Object

Emits the module script that loads .mrb bytecode and boots the lilac-compiled wasm. Inlines the boot logic instead of depending on @takahashim/lilac-compiled's published index.js — the npm boot helper has occasionally drifted from the bridge's current API (e.g. loadIrep rename → loadBytecode) and a self-contained module is one fewer moving part to keep in sync. The data-lilac-bootstrap attribute marks the tag so a future asset-pipeline pass can rewrite the URLs.

Lilac.start is NOT called here via vm.eval: the compiled wasm excludes mruby-compiler / mruby-eval, so post-load eval of arbitrary Ruby source is unsupported. Instead the builder appends Lilac.start to the bundle so it runs as part of loadBytecode (decisions §20.6 caveat).



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# File 'lib/lilac/cli/build/compiled_boot_module.rb', line 49

def render(mrb_filenames, package_urls: [], delivery: :inline)
  # Accept either a single filename or an array (used by the
  # :bundle delivery path to chain bundle.mrb + page-inline.mrb in
  # one VM).
  mrb_filenames = Array(mrb_filenames)

  # Package `.mrb` bundles load BEFORE the user bytecode so any
  # `Scanner.register("ClassName")` calls (and the Handler classes
  # they refer to) are ready by the time component mount runs.
  # Mirrors the load ordering in `npm/lilac-compiled/index.js`'s
  # boot helper.
  package_loads = package_urls.map do |url|
    "vm.loadBytecode(new Uint8Array(await (await fetch(#{url.inspect})).arrayBuffer()));"
  end
  bytecode_loads = mrb_filenames.map do |filename|
    %(vm.loadBytecode(new Uint8Array(await (await fetch("./#{filename}")).arrayBuffer())));
  end
  all_loads = (package_loads + bytecode_loads).join("\n  ")

  # :bundle delivery: the compiled wasm has no parser, so unlike
  # the :full boot helper we can't `vm.eval` bundle scripts —
  # those land in the chained .mrb above. But we still need to
  # pull the bundle's <template> elements into the live document
  # before `Lilac.start` runs (which is in the page-local /
  # start-only .mrb). Fetch + DOMParser the bundle and append
  # each <template>; scripts inside the bundle are intentionally
  # ignored (they don't exist for :compiled bundles).
  bundle_block =
    if delivery == :bundle
      <<~JS.chomp.gsub(/^/, '  ')
        for (const link of document.querySelectorAll('link[rel="lilac-bundle"]')) {
          const res = await fetch(link.getAttribute("href"));
          const doc = new DOMParser().parseFromString(await res.text(), "text/html");
          for (const tpl of doc.querySelectorAll("template")) {
            document.body.appendChild(tpl.cloneNode(true));
          }
        }
      JS
    end

  body_parts = []
  body_parts << bundle_block if bundle_block
  body_parts << "  #{all_loads}" unless all_loads.empty?

  <<~HTML.strip
    <script type="module" data-lilac-bootstrap>
      import { createVM } from "./vendor/lilac-compiled/mruby-wasm-js/index.js";
      const vm = await createVM({ wasm: "./vendor/lilac-compiled/lilac.wasm" });
    #{body_parts.join("\n")}
    </script>
  HTML
end