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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
/* JavaScript module (as in, the syntactic construct) operations. */
#ifndef js_Modules_h
#define js_Modules_h
#include <stdint.h> // uint32_t
#include "jstypes.h" // JS_PUBLIC_API
#include "js/AllocPolicy.h" // js::SystemAllocPolicy
#include "js/ColumnNumber.h" // JS::ColumnNumberOneOrigin
#include "js/CompileOptions.h" // JS::ReadOnlyCompileOptions
#include "js/RootingAPI.h" // JS::{Mutable,}Handle
#include "js/Value.h" // JS::Value
#include "js/Vector.h" // js::Vector
struct JS_PUBLIC_API JSContext;
class JS_PUBLIC_API JSObject;
struct JS_PUBLIC_API JSRuntime;
class JS_PUBLIC_API JSString;
namespace JS {
template <typename UnitT>
class SourceText;
} // namespace JS
namespace mozilla {
union Utf8Unit;
}
namespace JS {
enum class ModuleType : uint32_t { Unknown = 0, JavaScript, JSON };
/**
* The HostResolveImportedModule hook.
*
*
* This embedding-defined hook is used to implement module loading. It is called
* to get or create a module object corresponding to |moduleRequest| occurring
* in the context of the script or module with private value
* |referencingPrivate|.
*
* The module specifier string for the request can be obtained by calling
* JS::GetModuleRequestSpecifier.
*
* The private value for a script or module is set with JS::SetScriptPrivate or
* JS::SetModulePrivate. It's assumed that the embedding can handle receiving
* either here.
*
* This hook must obey the restrictions defined in the spec:
* - Each time the hook is called with the same arguemnts, the same module must
* be returned.
* - If a module cannot be created for the given arguments, an exception must
* be thrown.
*
* This is a synchronous operation.
*/
using ModuleResolveHook = JSObject* (*)(JSContext* cx,
Handle<Value> referencingPrivate,
Handle<JSObject*> moduleRequest);
/**
* Get the HostResolveImportedModule hook for the runtime.
*/
extern JS_PUBLIC_API ModuleResolveHook GetModuleResolveHook(JSRuntime* rt);
/**
* Set the HostResolveImportedModule hook for the runtime to the given function.
*/
extern JS_PUBLIC_API void SetModuleResolveHook(JSRuntime* rt,
ModuleResolveHook func);
/**
* The module metadata hook.
*
*
* Populate the |metaObject| object returned when import.meta is evaluated in
* the context of the script or module with private value |privateValue|.
*
* This is based on the spec's HostGetImportMetaProperties hook but defines
* properties on the meta object directly rather than returning a list.
*/
using ModuleMetadataHook = bool (*)(JSContext* cx, Handle<Value> privateValue,
Handle<JSObject*> metaObject);
/**
* Get the hook for populating the import.meta metadata object.
*/
extern JS_PUBLIC_API ModuleMetadataHook GetModuleMetadataHook(JSRuntime* rt);
/**
* Set the hook for populating the import.meta metadata object to the given
* function.
*/
extern JS_PUBLIC_API void SetModuleMetadataHook(JSRuntime* rt,
ModuleMetadataHook func);
/**
* The HostImportModuleDynamically hook.
*
*
* Used to implement dynamic module import. Called when evaluating import()
* expressions.
*
* This starts an asynchronous operation. Some time after this hook is called
* the embedding must call JS::FinishDynamicModuleImport() passing the
* |referencingPrivate|, |moduleRequest| and |promise| arguments from the
* call. This must happen for both success and failure cases.
*
* In the meantime the embedding can take whatever steps it needs to make the
* module available. If successful, after calling FinishDynamicModuleImport()
* the module should be returned by the resolve hook when passed
* |referencingPrivate| and |moduleRequest|.
*/
using ModuleDynamicImportHook = bool (*)(JSContext* cx,
Handle<Value> referencingPrivate,
Handle<JSObject*> moduleRequest,
Handle<JSObject*> promise);
/**
* Get the HostImportModuleDynamically hook for the runtime.
*/
extern JS_PUBLIC_API ModuleDynamicImportHook
GetModuleDynamicImportHook(JSRuntime* rt);
/**
* Set the HostImportModuleDynamically hook for the runtime to the given
* function.
*
* If this hook is not set (or set to nullptr) then the JS engine will throw an
* exception if dynamic module import is attempted.
*/
extern JS_PUBLIC_API void SetModuleDynamicImportHook(
JSRuntime* rt, ModuleDynamicImportHook func);
/**
* This must be called after a dynamic import operation is complete.
*
* If |evaluationPromise| is rejected, the rejection reason will be used to
* complete the user's promise.
*/
extern JS_PUBLIC_API bool FinishDynamicModuleImport(
JSContext* cx, Handle<JSObject*> evaluationPromise,
Handle<Value> referencingPrivate, Handle<JSObject*> moduleRequest,
Handle<JSObject*> promise);
/**
* Parse the given source buffer as a module in the scope of the current global
* of cx and return a source text module record.
*/
extern JS_PUBLIC_API JSObject* CompileModule(
JSContext* cx, const ReadOnlyCompileOptions& options,
SourceText<char16_t>& srcBuf);
/**
* Parse the given source buffer as a module in the scope of the current global
* of cx and return a source text module record. An error is reported if a
* UTF-8 encoding error is encountered.
*/
extern JS_PUBLIC_API JSObject* CompileModule(
JSContext* cx, const ReadOnlyCompileOptions& options,
SourceText<mozilla::Utf8Unit>& srcBuf);
/**
* Parse the given source buffer as a JSON module in the scope of the current
* global of cx and return a synthetic module record.
*/
extern JS_PUBLIC_API JSObject* CompileJsonModule(
JSContext* cx, const ReadOnlyCompileOptions& options,
SourceText<char16_t>& srcBuf);
/**
* Set a private value associated with a source text module record.
*/
extern JS_PUBLIC_API void SetModulePrivate(JSObject* module,
const Value& value);
/**
* Clear the private value associated with a source text module record.
*
* This is used during unlinking and can be called on a gray module, skipping
* the usual checks.
*/
extern JS_PUBLIC_API void ClearModulePrivate(JSObject* module);
/**
* Get the private value associated with a source text module record.
*/
extern JS_PUBLIC_API Value GetModulePrivate(JSObject* module);
/*
* Perform the ModuleLink operation on the given source text module record.
*
* This transitively resolves all module dependencies (calling the
* HostResolveImportedModule hook) and initializes the environment record for
* the module.
*/
extern JS_PUBLIC_API bool ModuleLink(JSContext* cx,
Handle<JSObject*> moduleRecord);
/*
* Perform the ModuleEvaluate operation on the given source text module record
* and returns a bool. A result value is returned in result and is either
* undefined (and ignored) or a promise (if Top Level Await is enabled).
*
* If this module has already been evaluated, it returns the evaluation
* promise. Otherwise, it transitively evaluates all dependences of this module
* and then evaluates this module.
*
* ModuleLink must have completed prior to calling this.
*/
extern JS_PUBLIC_API bool ModuleEvaluate(JSContext* cx,
Handle<JSObject*> moduleRecord,
MutableHandleValue rval);
enum ModuleErrorBehaviour {
// Report module evaluation errors asynchronously when the evaluation promise
// is rejected. This is used for web content.
ReportModuleErrorsAsync,
// Throw module evaluation errors synchronously by setting an exception on the
// context. Does not support modules that use top-level await.
ThrowModuleErrorsSync
};
/*
* If a module evaluation fails, unwrap the resulting evaluation promise
* and rethrow.
*
* This does nothing if this module succeeds in evaluation. Otherwise, it
* takes the reason for the module throwing, unwraps it and throws it as a
* regular error rather than as an uncaught promise.
*
* ModuleEvaluate must have completed prior to calling this.
*/
extern JS_PUBLIC_API bool ThrowOnModuleEvaluationFailure(
JSContext* cx, Handle<JSObject*> evaluationPromise,
ModuleErrorBehaviour errorBehaviour = ReportModuleErrorsAsync);
/*
* Functions to access the module specifiers of a source text module record used
* to request module imports.
*
* Clients can use GetRequestedModulesCount() to get the number of specifiers
* and GetRequestedModuleSpecifier() / GetRequestedModuleSourcePos() to get the
* individual elements.
*/
extern JS_PUBLIC_API uint32_t
GetRequestedModulesCount(JSContext* cx, Handle<JSObject*> moduleRecord);
extern JS_PUBLIC_API JSString* GetRequestedModuleSpecifier(
JSContext* cx, Handle<JSObject*> moduleRecord, uint32_t index);
/*
* Get the position of a requested module's name in the source.
*/
extern JS_PUBLIC_API void GetRequestedModuleSourcePos(
JSContext* cx, Handle<JSObject*> moduleRecord, uint32_t index,
uint32_t* lineNumber, JS::ColumnNumberOneOrigin* columnNumber);
/*
* Get the top-level script for a module which has not yet been executed.
*/
extern JS_PUBLIC_API JSScript* GetModuleScript(Handle<JSObject*> moduleRecord);
extern JS_PUBLIC_API JSObject* CreateModuleRequest(
JSContext* cx, Handle<JSString*> specifierArg);
extern JS_PUBLIC_API JSString* GetModuleRequestSpecifier(
JSContext* cx, Handle<JSObject*> moduleRequestArg);
/*
* Get the module record for a module script.
*/
extern JS_PUBLIC_API JSObject* GetModuleObject(Handle<JSScript*> moduleScript);
/*
* Get the namespace object for a module.
*/
extern JS_PUBLIC_API JSObject* GetModuleNamespace(
JSContext* cx, Handle<JSObject*> moduleRecord);
extern JS_PUBLIC_API JSObject* GetModuleForNamespace(
JSContext* cx, Handle<JSObject*> moduleNamespace);
extern JS_PUBLIC_API JSObject* GetModuleEnvironment(
JSContext* cx, Handle<JSObject*> moduleObj);
/*
* Clear all bindings in a module's environment. Used during shutdown.
*/
extern JS_PUBLIC_API void ClearModuleEnvironment(JSObject* moduleObj);
extern JS_PUBLIC_API bool ModuleIsLinked(JSObject* moduleObj);
} // namespace JS
#endif // js_Modules_h