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// Copyright (c) 2017-2022 Cloudflare, Inc.
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// Licensed under the Apache 2.0 license found in the LICENSE file or at:
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//     https://opensource.org/licenses/Apache-2.0
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#include "module.h"
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#include <workerd/io/features.h>
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#include <workerd/jsg/modules-new.h>
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#include <workerd/jsg/url.h>
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namespace workerd::api::node {
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bool ModuleUtil::isBuiltin(kj::String specifier) {
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  return jsg::checkNodeSpecifier(specifier) != kj::none;
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}
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jsg::JsValue ModuleUtil::createRequire(jsg::Lock& js, kj::String path) {
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  // Node.js requires that the specifier path is a File URL or an absolute
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  // file path string. To be compliant, we will convert whatever specifier
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  // is into a File URL if possible, then take the path as the actual
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  // specifier to use.
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  auto parsed = JSG_REQUIRE_NONNULL(jsg::Url::tryParse(path.asPtr(), "file:///"_kj), TypeError,
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      "The argument must be a file URL object, "
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      "a file URL string, or an absolute path string.");
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  if (FeatureFlags::get(js).getNewModuleRegistry()) {
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    return jsg::JsValue(js.wrapReturningFunction(js.v8Context(),
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        [referrer = parsed.clone()](jsg::Lock& js,
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            const v8::FunctionCallbackInfo<v8::Value>& args) -> v8::Local<v8::Value> {
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      auto specifier = kj::str(args[0]);
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      if (jsg::isNodeJsCompatEnabled(js)) {
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        KJ_IF_SOME(nodeSpec, jsg::checkNodeSpecifier(specifier)) {
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          specifier = kj::mv(nodeSpec);
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        }
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      }
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      KJ_IF_SOME(val,
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          jsg::modules::ModuleRegistry::tryResolveModuleNamespace(js, specifier,
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              jsg::modules::ResolveContext::Type::BUNDLE,
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              jsg::modules::ResolveContext::Source::REQUIRE, referrer,
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              jsg::modules::UnwrapDefault::YES)) {
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        return val;
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      }
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      JSG_FAIL_REQUIRE(Error, kj::str("Module not found: ", specifier));
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    }));
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  }
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  // We do not currently handle specifiers as URLs, so let's treat any
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  // input that has query string params or hash fragments as errors.
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  if (parsed.getSearch().size() > 0 || parsed.getHash().size() > 0) {
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    JSG_FAIL_REQUIRE(
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        Error, "The specifier must not have query string parameters or hash fragments.");
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  }
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  // The specifier must be a file: URL
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  JSG_REQUIRE(parsed.getProtocol() == "file:"_kj, TypeError, "The specifier must be a file: URL.");
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  return jsg::JsValue(js.wrapReturningFunction(js.v8Context(),
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      [referrer = kj::str(parsed.getPathname())](
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          jsg::Lock& js, const v8::FunctionCallbackInfo<v8::Value>& args) -> v8::Local<v8::Value> {
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    auto registry = jsg::ModuleRegistry::from(js);
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    // TODO(soon): This will need to be updated to support the new module registry
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    // when that is fully implemented.
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    JSG_REQUIRE(registry != nullptr, Error, "Module registry not available.");
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    auto ref = ([&] {
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      try {
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        return kj::Path::parse(referrer.slice(1));
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      } catch (kj::Exception& e) {
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        JSG_FAIL_REQUIRE(Error, kj::str("Invalid referrer path: ", referrer.slice(1)));
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      }
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    })();
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    auto spec = kj::str(args[0]);
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    if (jsg::isNodeJsCompatEnabled(js)) {
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      KJ_IF_SOME(nodeSpec, jsg::checkNodeSpecifier(spec)) {
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        spec = kj::mv(nodeSpec);
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      }
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    }
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    static const kj::Path kRoot = kj::Path::parse("");
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    kj::Path targetPath = ([&] {
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      // If the specifier begins with one of our known prefixes, let's not resolve
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      // it against the referrer.
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      try {
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        if (spec.startsWith("node:") || spec.startsWith("cloudflare:") ||
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            spec.startsWith("workerd:")) {
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          return kj::Path::parse(spec);
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        }
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        return ref == kRoot ? kj::Path::parse(spec) : ref.parent().eval(spec);
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      } catch (kj::Exception&) {
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        JSG_FAIL_REQUIRE(Error, kj::str("Invalid specifier path: ", spec));
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      }
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    })();
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    // require() is only exposed to worker bundle modules so the resolve here is only
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    // permitted to require worker bundle or built-in modules. Internal modules are
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    // excluded.
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    auto& info = JSG_REQUIRE_NONNULL(
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        registry->resolve(js, targetPath, ref, jsg::ModuleRegistry::ResolveOption::DEFAULT,
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            jsg::ModuleRegistry::ResolveMethod::REQUIRE, spec.asPtr()),
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        Error, "No such module \"", targetPath.toString(), "\".");
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    jsg::ModuleRegistry::RequireImplOptions options =
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        jsg::ModuleRegistry::RequireImplOptions::DEFAULT;
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    if (info.maybeSynthetic != kj::none) {
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      options = jsg::ModuleRegistry::RequireImplOptions::EXPORT_DEFAULT;
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    }
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    return jsg::ModuleRegistry::requireImpl(js, info, options);
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  }));
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}
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}  // namespace workerd::api::node