Implement `onResolve` plugins in `Bun.build()`, support multiple onLoad and onResolve plugins (#2739)

* its 2023

* WIP `onResolve` plugins

* more progress

* it compiles

* Lots of small fixes

* Seems to work excluding entry points

* Update BundlerPluginBuiltins.cpp

---------

Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>

1 files changed, 20 insertions, 119 deletions

diff --git a/src/bun.js/bindings/ModuleLoader.cpp b/src/bun.js/bindings/ModuleLoader.cpp
index 00b975d88..40e41b083 100644
--- a/src/bun.js/bindings/ModuleLoader.cpp
+++ b/src/bun.js/bindings/ModuleLoader.cpp
@@ -40,56 +40,7 @@ namespace Bun {
 using namespace Zig;
 using namespace WebCore;
 
-extern "C" BunLoaderType Bun__getDefaultLoader(JSC::JSGlobalObject*, const ZigString* specifier);
-extern "C" BunLoaderType JSBundlerPlugin__getDefaultLoader(void* context);
-extern "C" void JSBundlerPlugin__OnLoadAsync(void* ctx, EncodedJSValue errorValue, ZigString* sourceCode, BunLoaderType loader);
-OnLoadResult handleOnLoadResult(Zig::GlobalObject* globalObject, JSC::JSValue objectValue, const ZigString* specifier, void* context);
-
-JSValue handleVirtualModuleResultForJSBundlerPlugin(
-    Zig::GlobalObject* globalObject,
-    JSValue virtualModuleResult,
-    const ZigString* specifier,
-    const ZigString* referrer,
-    void* bundlerPluginContext)
-{
-    auto onLoadResult = handleOnLoadResult(globalObject, virtualModuleResult, specifier, bundlerPluginContext);
-    JSC::VM& vm = globalObject->vm();
-
-    switch (onLoadResult.type) {
-    case OnLoadResultTypeCode: {
-        JSBundlerPlugin__OnLoadAsync(bundlerPluginContext, JSValue::encode({}), &onLoadResult.value.sourceText.string, onLoadResult.value.sourceText.loader);
-        return jsUndefined();
-    }
-    case OnLoadResultTypeError: {
-        JSBundlerPlugin__OnLoadAsync(bundlerPluginContext, JSValue::encode(onLoadResult.value.error), nullptr, BunLoaderTypeNone);
-        return jsUndefined();
-    }
-
-    case OnLoadResultTypePromise: {
-        JSFunction* performPromiseThenFunction = globalObject->performPromiseThenFunction();
-        auto callData = JSC::getCallData(performPromiseThenFunction);
-        ASSERT(callData.type != CallData::Type::None);
-        auto specifierString = Zig::toString(*specifier);
-        auto referrerString = referrer ? Zig::toString(*referrer) : String();
-        PendingVirtualModuleResult* pendingModule = PendingVirtualModuleResult::create(globalObject, specifierString, referrerString, bundlerPluginContext);
-        pendingModule->internalField(2).set(vm, pendingModule, virtualModuleResult);
-        JSC::JSPromise* promise = pendingModule->promise();
-
-        MarkedArgumentBuffer arguments;
-        arguments.append(promise);
-        arguments.append(globalObject->thenable(jsFunctionOnLoadObjectResultResolveForJSBundlerPlugin));
-        arguments.append(globalObject->thenable(jsFunctionOnLoadObjectResultRejectForJSBundlerPlugin));
-        arguments.append(jsUndefined());
-        arguments.append(pendingModule);
-        ASSERT(!arguments.hasOverflowed());
-        JSC::call(globalObject, performPromiseThenFunction, callData, jsUndefined(), arguments);
-        return promise;
-    }
-    default: {
-        __builtin_unreachable();
-    }
-    }
-}
+extern "C" BunLoaderType Bun__getDefaultLoader(JSC::JSGlobalObject*, ZigString* specifier);
 
 static JSC::JSInternalPromise* rejectedInternalPromise(JSC::JSGlobalObject* globalObject, JSC::JSValue value)
 {
@@ -137,16 +88,11 @@ JSC::JSInternalPromise* PendingVirtualModuleResult::internalPromise()
     return jsCast<JSC::JSInternalPromise*>(internalField(2).get());
 }
 
-JSC::JSPromise* PendingVirtualModuleResult::promise()
-{
-    return jsCast<JSC::JSPromise*>(internalField(2).get());
-}
-
 const ClassInfo PendingVirtualModuleResult::s_info = { "PendingVirtualModule"_s, &Base::s_info, nullptr, nullptr, CREATE_METHOD_TABLE(PendingVirtualModuleResult) };
 
-PendingVirtualModuleResult* PendingVirtualModuleResult::create(VM& vm, Structure* structure, void* bundlerPluginContext)
+PendingVirtualModuleResult* PendingVirtualModuleResult::create(VM& vm, Structure* structure)
 {
-    PendingVirtualModuleResult* mod = new (NotNull, allocateCell<PendingVirtualModuleResult>(vm)) PendingVirtualModuleResult(vm, structure, bundlerPluginContext);
+    PendingVirtualModuleResult* mod = new (NotNull, allocateCell<PendingVirtualModuleResult>(vm)) PendingVirtualModuleResult(vm, structure);
     return mod;
 }
 Structure* PendingVirtualModuleResult::createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
@@ -154,9 +100,8 @@ Structure* PendingVirtualModuleResult::createStructure(VM& vm, JSGlobalObject* g
     return Structure::create(vm, globalObject, prototype, TypeInfo(CellType, StructureFlags), info());
 }
 
-PendingVirtualModuleResult::PendingVirtualModuleResult(VM& vm, Structure* structure, void* bundlerPluginContext)
+PendingVirtualModuleResult::PendingVirtualModuleResult(VM& vm, Structure* structure)
     : Base(vm, structure)
-    , m_bundlerPluginContext(bundlerPluginContext)
 {
 }
 
@@ -165,9 +110,7 @@ void PendingVirtualModuleResult::finishCreation(VM& vm, const WTF::String& speci
     Base::finishCreation(vm);
     Base::internalField(0).set(vm, this, JSC::jsString(vm, specifier));
     Base::internalField(1).set(vm, this, JSC::jsString(vm, referrer));
-    if (!this->m_bundlerPluginContext) {
-        Base::internalField(2).set(vm, this, JSC::JSInternalPromise::create(vm, globalObject()->internalPromiseStructure()));
-    }
+    Base::internalField(2).set(vm, this, JSC::JSInternalPromise::create(vm, globalObject()->internalPromiseStructure()));
 }
 
 template<typename Visitor>
@@ -180,22 +123,21 @@ void PendingVirtualModuleResult::visitChildrenImpl(JSCell* cell, Visitor& visito
 
 DEFINE_VISIT_CHILDREN(PendingVirtualModuleResult);
 
-PendingVirtualModuleResult* PendingVirtualModuleResult::create(JSC::JSGlobalObject* globalObject, const WTF::String& specifier, const WTF::String& referrer, void* bundlerPluginContext)
+PendingVirtualModuleResult* PendingVirtualModuleResult::create(JSC::JSGlobalObject* globalObject, const WTF::String& specifier, const WTF::String& referrer)
 {
-    auto* virtualModule = create(globalObject->vm(), reinterpret_cast<Zig::GlobalObject*>(globalObject)->pendingVirtualModuleResultStructure(), bundlerPluginContext);
+    auto* virtualModule = create(globalObject->vm(), reinterpret_cast<Zig::GlobalObject*>(globalObject)->pendingVirtualModuleResultStructure());
     virtualModule->finishCreation(globalObject->vm(), specifier, referrer);
     return virtualModule;
 }
 
-OnLoadResult handleOnLoadResultNotPromise(Zig::GlobalObject* globalObject, JSC::JSValue objectValue, const ZigString* specifier, void* bunPluginContext)
+OnLoadResult handleOnLoadResultNotPromise(Zig::GlobalObject* globalObject, JSC::JSValue objectValue, ZigString* specifier)
 {
     OnLoadResult result = {};
     result.type = OnLoadResultTypeError;
-    result.bundlerPluginContext = bunPluginContext;
     JSC::VM& vm = globalObject->vm();
     result.value.error = JSC::jsUndefined();
     auto scope = DECLARE_THROW_SCOPE(vm);
-    BunLoaderType loader = bunPluginContext ? JSBundlerPlugin__getDefaultLoader(bunPluginContext) : Bun__getDefaultLoader(globalObject, specifier);
+    BunLoaderType loader = Bun__getDefaultLoader(globalObject, specifier);
 
     if (JSC::Exception* exception = JSC::jsDynamicCast<JSC::Exception*>(objectValue)) {
         result.value.error = exception->value();
@@ -269,17 +211,16 @@ OnLoadResult handleOnLoadResultNotPromise(Zig::GlobalObject* globalObject, JSC::
     return result;
 }
 
-OnLoadResult handleOnLoadResult(Zig::GlobalObject* globalObject, JSC::JSValue objectValue, const ZigString* specifier, void* context)
+static OnLoadResult handleOnLoadResult(Zig::GlobalObject* globalObject, JSC::JSValue objectValue, ZigString* specifier)
 {
     if (JSC::JSPromise* promise = JSC::jsDynamicCast<JSC::JSPromise*>(objectValue)) {
         OnLoadResult result = {};
         result.type = OnLoadResultTypePromise;
         result.value.promise = objectValue;
-        result.bundlerPluginContext = context;
         return result;
     }
 
-    return handleOnLoadResultNotPromise(globalObject, objectValue, specifier, context);
+    return handleOnLoadResultNotPromise(globalObject, objectValue, specifier);
 }
 
 template<bool allowPromise>
@@ -287,10 +228,10 @@ static JSValue handleVirtualModuleResult(
     Zig::GlobalObject* globalObject,
     JSValue virtualModuleResult,
     ErrorableResolvedSource* res,
-    const ZigString* specifier,
-    const ZigString* referrer)
+    ZigString* specifier,
+    ZigString* referrer)
 {
-    auto onLoadResult = handleOnLoadResult(globalObject, virtualModuleResult, specifier, nullptr);
+    auto onLoadResult = handleOnLoadResult(globalObject, virtualModuleResult, specifier);
     JSC::VM& vm = globalObject->vm();
     auto scope = DECLARE_THROW_SCOPE(vm);
 
@@ -412,8 +353,8 @@ template<bool allowPromise>
 static JSValue fetchSourceCode(
     Zig::GlobalObject* globalObject,
     ErrorableResolvedSource* res,
-    const ZigString* specifier,
-    const ZigString* referrer)
+    ZigString* specifier,
+    ZigString* referrer)
 {
     void* bunVM = globalObject->bunVM();
     auto& vm = globalObject->vm();
@@ -545,46 +486,6 @@ static JSValue fetchSourceCode(
     return rejectOrResolve(JSC::JSSourceCode::create(vm, JSC::SourceCode(WTFMove(provider))));
 }
 
-extern "C" JSC::EncodedJSValue jsFunctionOnLoadObjectResultResolveForJSBundlerPlugin(JSC::JSGlobalObject* globalObject, JSC::CallFrame* callFrame)
-{
-    JSC::VM& vm = globalObject->vm();
-    ErrorableResolvedSource res = {};
-    res.success = false;
-    JSC::JSValue objectResult = callFrame->argument(0);
-    PendingVirtualModuleResult* pendingModule = JSC::jsCast<PendingVirtualModuleResult*>(callFrame->argument(1));
-    JSC::JSValue specifierString = pendingModule->internalField(0).get();
-    JSC::JSValue referrerString = pendingModule->internalField(1).get();
-    pendingModule->internalField(0).set(vm, pendingModule, JSC::jsUndefined());
-    pendingModule->internalField(1).set(vm, pendingModule, JSC::jsUndefined());
-    void* bunPluginContext = pendingModule->m_bundlerPluginContext;
-    JSC::JSPromise* promise = pendingModule->promise();
-
-    ZigString specifier = Zig::toZigString(specifierString, globalObject);
-    ZigString referrer = Zig::toZigString(referrerString, globalObject);
-    return JSC::JSValue::encode(
-        handleVirtualModuleResultForJSBundlerPlugin(reinterpret_cast<Zig::GlobalObject*>(globalObject), objectResult, &specifier, &referrer, bunPluginContext));
-}
-
-extern "C" JSC::EncodedJSValue jsFunctionOnLoadObjectResultRejectForJSBundlerPlugin(JSC::JSGlobalObject* globalObject, JSC::CallFrame* callFrame)
-{
-    JSC::VM& vm = globalObject->vm();
-    ErrorableResolvedSource res = {};
-    JSC::JSValue reason = callFrame->argument(0);
-    PendingVirtualModuleResult* pendingModule = JSC::jsCast<PendingVirtualModuleResult*>(callFrame->argument(1));
-    JSC::JSValue specifierString = pendingModule->internalField(0).get();
-    JSC::JSValue referrerString = pendingModule->internalField(1).get();
-    pendingModule->internalField(0).set(vm, pendingModule, JSC::jsUndefined());
-    pendingModule->internalField(1).set(vm, pendingModule, JSC::jsUndefined());
-
-    ZigString specifier = Zig::toZigString(specifierString, globalObject);
-    ZigString referrer = Zig::toZigString(referrerString, globalObject);
-    pendingModule->internalField(2).set(vm, pendingModule, JSC::jsUndefined());
-
-    JSBundlerPlugin__OnLoadAsync(pendingModule->m_bundlerPluginContext, JSValue::encode(reason), nullptr, BunLoaderTypeNone);
-
-    return JSValue::encode(reason);
-}
-
 extern "C" JSC::EncodedJSValue jsFunctionOnLoadObjectResultResolve(JSC::JSGlobalObject* globalObject, JSC::CallFrame* callFrame)
 {
     JSC::VM& vm = globalObject->vm();
@@ -643,8 +544,8 @@ extern "C" JSC::EncodedJSValue jsFunctionOnLoadObjectResultReject(JSC::JSGlobalO
 JSValue fetchSourceCodeSync(
     Zig::GlobalObject* globalObject,
     ErrorableResolvedSource* res,
-    const ZigString* specifier,
-    const ZigString* referrer)
+    ZigString* specifier,
+    ZigString* referrer)
 {
     return fetchSourceCode<false>(globalObject, res, specifier, referrer);
 }
@@ -652,8 +553,8 @@ JSValue fetchSourceCodeSync(
 JSValue fetchSourceCodeAsync(
     Zig::GlobalObject* globalObject,
     ErrorableResolvedSource* res,
-    const ZigString* specifier,
-    const ZigString* referrer)
+    ZigString* specifier,
+    ZigString* referrer)
 {
     return fetchSourceCode<true>(globalObject, res, specifier, referrer);
 }