lang
library
Classes
AbsolutePathValidator
Validates that a URI contains an absolute path (starting with '/').
AbstractFileUtility
A foundational utility class providing shared logic, configuration access,
and resolution helpers for file-system driven runtime analysis.
AbstractRuntimeHint <T >
A generic, opt-in base class for implementing strongly typed
RuntimeHint providers.
AdaptableList
A specialized list collection that can adapt itself or another source
into a strongly-typed List of elements.
AdaptableMap
A specialized map collection that can adapt itself or another source
into a strongly-typed Map of keys and values.
AdaptableSet
A specialized set collection that can adapt itself or another source
into a strongly-typed Set of elements.
AllowedDomainsValidator
Validates that a URI's host matches one of the allowed domains.
Annotation
Provides reflective access to annotations applied to declarations.
AnnotationDeclaration
Represents an annotation that has been applied to a class, method,
field, parameter, or other Dart declarations at runtime.
AnnotationFieldDeclaration
Represents a field of an annotation.
AotRuntimeExecutor
An RuntimeExecutor implementation that leverages Ahead-of-Time (AOT)
generative hints to perform instance creation, method invocation, and
field access at runtime without relying on mirrors or dynamic reflection.
ApplicationRuntimeScanner
A runtime scanner responsible for analyzing application-level Dart code
and generating runtime metadata required for reflection, asset discovery,
and package resolution.
ArrayList <E >
A resizable array implementation similar to Java's ArrayList.
Asset
Represents a non-Dart static resource (e.g., HTML, CSS, images).
AssetBuilder
Defines a contract for classes that build Asset instances from a
given template identifier.
AssetLoader
A configurable asset bundler for loading files from Dart packages.
AssetLoaderInterface
Abstract interface for asset bundling operations.
AssetLoaderManager
Core manager class that handles all asset bundling logic.
AssetPathResource
Represents a resource that can be loaded from a path-based asset.
AssetResource
An abstract representation of a resource that wraps either:
Author
Annotation to describe the author of a declaration.
BaseDeclaration
Base abstraction for all JetLeaf declaration models.
BaseStream <T , S extends BaseStream <T , S > >
Base interface for streams, which are sequences of elements supporting
sequential and parallel aggregate operations.
BigDecimal
A wrapper class for precise decimal arithmetic.
BigInteger
A wrapper class for arbitrary precision integers.
Boolean
A wrapper class for bool that provides Java-like functionality and methods.
BufferedInputStream
A BufferedInputStream adds functionality to another input stream-namely,
the ability to buffer the input and to support the mark and reset methods.
BufferedOutputStream
The class implements a buffered output stream.
BufferedReader
Reads text from a character-input stream, buffering characters so as to
provide for the efficient reading of characters, arrays, and lines.
BufferedWriter
Writes text to a character-output stream, buffering characters to provide
efficient writing of characters, arrays, and strings.
BuildArg
Centralized parser and accessor for build-time command-line arguments .
BulkChange
Represents multiple observable events grouped together.
Byte
A comprehensive wrapper class for byte operations, supporting both single bytes and byte collections.
ByteArray
A wrapper for byte arrays similar to Java's byte[] with utility methods.
ByteArrayInputStream
A byte-based input stream that reads from a Uint8List buffer.
ByteArrayOutputStream
An OutputStream that writes to a growable internal byte buffer.
ByteStream
A stream of bytes similar to Java's InputStream/OutputStream.
CaseInsensitiveMap <V >
A map that performs case-insensitive string key lookups while preserving
the original casing of keys.
Character
A wrapper class for single characters that provides Java-like functionality.
Class <T >
Provides a unified, reflective interface to access Dart class types
and their associated metadata at runtime.
ClassDeclaration
Represents a reflected Dart class and all of its metadata, including
fields, methods, constructors, superclasses, mixins, interfaces, and
declaration-level modifiers (abstract, sealed, etc.).
ClassGettable <T >
Provides a contract for types capable of exposing their associated
runtime Class metadata representation within the JetLeaf reflection system.
ClassPathResource
Provides access to resources, classes, methods, and fields located
in a package's classpath.
ClassReference
A lightweight class reference containing minimal structural information
about a Dart class.
ClassType <T >
The ClassType class in Jetleaf represents a reference to a Dart
class, optionally including metadata such as package, protection domain,
or type declaration.
ClassUtils
A utility class that provides static methods for working with class hierarchies
and type relationships in Dart's reflection system.
Closeable
An object that may hold resources until it is closed.
ClosureDeclaration
Represents a closure or anonymous function as a class-like declaration
within the JetLeaf reflection system.
Collector <T , A , R >
A mutable reduction operation that accumulates input elements into a mutable
result container, optionally transforming the accumulated result into a final
representation after all input elements have been processed.
Collectors
Implementations of Collector that implement various useful reduction
operations, such as accumulating elements into collections, summarizing
elements according to various criteria, etc.
Comparator <T >
An abstract class that imposes a total ordering on a collection of objects of type T.
ConfigurableRuntimeScannerSummary
An extension of RuntimeScannerSummary that allows mutating
its state during or after the scanning process.
ConsolePrintStream
A concrete implementation of PrintStream that writes to the console using stdout .
Constant
Constant class containing predefined constants used across the application.
Constructor
Provides reflective access to class constructor metadata and instantiation.
ConstructorDeclaration
Creates a new language range.
Currency
Abstract base class for currency operations following ISO 4217 standards.
DateTimeFormatter
A formatter and parser for date-time objects based on patterns, similar to Java's DateTimeFormatter.
Declaration
A named, typed declaration representing a concrete program element.
DefaultLibraryGenerator
Default implementation of LibraryGenerator responsible for producing
runtime declaration metadata from Dart libraries using the VM
mirror system and source-code analysis.
DefaultRuntimeExecutor
A robust runtime executor that coordinates between two resolver strategies
to handle dynamic operations on objects, methods, and fields at runtime.
DefaultRuntimeHintDescriptor
A concrete implementation of RuntimeHintDescriptor that stores hints in a simple list.
DefaultRuntimeScannerSummary
A default implementation of ConfigurableRuntimeScannerSummary that
holds the results of a Runtime scan including the build context,
timestamp, and all reported messages (errors, warnings, and info).
Double
A wrapper class for double that provides Java-like functionality and methods.
DoubleStream
A sequence of primitive double-valued elements supporting sequential and parallel
aggregate operations.
Dynamic
Abstract base class representing a dynamic or unconstrained type within
the JetLeaf type system.
EntityDeclaration
A uniquely identifiable declaration representing a runtime entity .
EnumDeclaration
Represents a reflected Dart enum type, providing access to its
enum entry names, metadata, and declared members (fields, methods).
EnumFieldDeclaration
Abstract base class representing a field (value) within an enum declaration.
EnumValue
Represents a single value within an enum type, providing full reflective
access to its metadata, declaration details, and runtime behavior.
Executable
Abstract base class for executable elements (methods, constructors, functions).
ExecutableArgument
Represents a fully normalized and transport-safe view of arguments passed
to an executable entity (constructor, method, function, or tear-off).
ExecutableArgumentResolver
A type-driven dependency injection utility for resolving arguments required
by an Executable such as a constructor, method, or function.
ExecutableInstantiator
Provides a high-level, reflection-based utility to dynamically instantiate
classes and invoke methods on objects at runtime, while automatically resolving
arguments and selecting the most appropriate executable.
ExecutableSelector
A flexible executable filtering and selection utility used to pick a
single Executable (e.g., a constructor, method, or function overload) from
a provided list based on declarative matching rules.
Field
Provides reflective access to class field metadata and value manipulation.
FieldAccess
Provides reflective access to fields of a class.
FieldDeclaration
Represents a field (variable) declared within a Dart class, extension, enum, or mixin.
FileInputStream
A FileInputStream obtains input bytes from a file in a file system.
FileOutputStream
A file output stream is an output stream for writing data to a File or
to a file descriptor.
FileReader
Convenience class for reading character files.
FileUtility
A utility class providing file-system and package-resolution helpers
for Dart and JetLeaf runtime environments.
FileWriter
Convenience class for writing character files.
Float
A wrapper class for single-precision floating point numbers.
Flushable
An object that can be flushed.
FunctionDeclaration
Specialized LinkDeclaration for function type references.
Garbage <T >
A lightweight, generic wrapper representing a tracked runtime resource
managed by the JetLeaf garbage collection system.
GarbageCollector
A centralized, map-backed runtime garbage manager used by JetLeaf
to track, evict, and periodically clean up cached or temporary objects.
GenerativeAsset
Base class representing a resource asset with a no-args constructor .
GenerativePackage
Base class representing a package resource with a no-args constructor .
Generic
A reflectable annotation that marks generic classes for type reflection.
GenericStream <T >
A sequence of elements supporting sequential and parallel aggregate operations.
GenericTypeParser
Provides utilities for parsing and analyzing generic type strings in Dart.
GenericTypeParsingResult
Represents the parsed structure of a generic type.
HashMap <K , V >
A custom implementation of a hash map that implements the Map<K, V> interface.
HashSet <E >
A custom implementation of a hash set that implements the Set<E> interface.
Hint
Represents the outcome of a runtime hint operation within the JetLeaf
execution pipeline.
HostValidator
Validates that a URI contains a hostname component.
HttpUrlConnection
A concrete implementation of UrlConnection for HTTP and HTTPS protocols.
InputStream
This abstract class is the superclass of all classes representing an input
stream of bytes.
InputStreamSource
A simple interface for objects that provide an InputStream .
Instance
A utility class for type checking, similar to Java's instanceof.
It also provides additional methods for type checking.
Integer
A wrapper class for int that provides Java-like functionality and methods.
InternalMockLibraryGenerator
We create this class for the purpose of internal testing of the JetLeaf's framework.
This class is only visible within the framework and not to be used by external users.
For users who want to test their application, they can use the MockLibraryGenerator
to bootstrap their application.
IntStream
A sequence of primitive int-valued elements supporting sequential and parallel
aggregate operations.
JitRuntimeExecutor
A reflection-based implementation of RuntimeExecutor using dart:mirrors.
LanguageRange
Represents a language range as defined in RFC 4647.
LibraryDeclaration
Represents a Dart library declaration within JetLeaf’s reflection
and generation system.
LibraryGenerator
Enhanced reflection generator that creates both metadata and reflector classes.
LinkDeclaration
Abstract base class for type references in reflection systems.
LinkedList <E >
A custom implementation of a doubly linked list that implements the standard List<E> interface.
LinkedQueue <E >
A queue implementation using a linked list structure, mimicking Java's LinkedList as Queue.
LinkedStack <E >
A stack implementation using a linked list structure, mimicking Java's LinkedList as Stack.
ListChange <T >
Represents a change in a List.
LocalDate
Represents a calendar date without time or timezone.
LocalDateTime
A date-time object without a timezone, composed of a LocalDate and LocalTime .
Locale
A representation of a locale, consisting of a language code and optional
country and variant codes.
LocalThread <T >
A Dart equivalent of Java's ThreadLocal, scoped to the current Isolate .
LocalThreadStorageBucket <T >
A mutable storage container for a LocalThread value, bound to a specific Isolate .
LocalTime
A value object representing a time of day without any date or timezone information.
LocatedFiles
A file–classification and scheduling model used by JetLeaf to
efficiently control what gets processed during a build.
Long
A wrapper class for large integers that provides Java-like functionality.
MapChange <K , V >
Represents a change in a Map.
MaterializedRuntimeHint <T >
A materialized runtime hint that provides a concrete representation
of its target type T while allowing runtime behavior overrides.
MaterialLibrary
A centralized, immutable registry of materialized Dart libraries
within the JetLeaf reflection and generation system. This is the backbone registry of JetLeaf’s reflection
system. It materializes raw libraries into a frozen, queryable structure
that enables fast, deterministic, and cross-domain type resolution.
Member
Abstract base class representing a member of a class that extends Executable .
MemberDeclaration
A source-level declaration that is owned by a class .
Method
Provides reflective access to class method metadata and invocation capabilities.
MethodDeclaration
Represents a method declaration in a Dart class, extension, mixin, or top-level scope.
MethodUtils
Provides reflective utility functions for working with JetLeaf runtime
Method and MethodDeclaration instances.
MixinDeclaration
Represents a reflected Dart mixin declaration, providing access to its
members, type constraints, and metadata.
MockLibraryGenerator
A mock implementation of LibraryGenerator that generates reflection metadata
using Dart's mirrors API without filesystem operations.
MockLibraryGeneratorParams
Configuration parameters for creating a MockLibraryGenerator .
MockRuntimeScanner
A mock implementation of RuntimeScanner designed for testing,
experimentation, and controlled runtime scanning scenarios.
NamedLocalThread <T >
A specialized LocalThread that includes a descriptive name for better debugging and identification.
NetworkInputStream
An InputStream implementation that reads bytes from a Dart Stream<List<int>> .
NetworkOutputStream
An OutputStream implementation that writes bytes to a Dart HttpClientRequest.
NoCredentialsValidator
Validates that a URI doesn't contain user credentials (username/password).
NoIpAddressValidator
Validates that a URI uses a domain name rather than a raw IP address.
NoSpacesValidator
Validates that a URI string doesn't contain any spaces.
Null
A minimal placeholder class representing a null-like object .
Obs <T >
A reactive wrapper for values, lists, or maps.
ObsEvent
A base class representing an event in an observable system.
Optional <T >
A container object which may or may not contain a non-null value.
OrderComparator
A comparator that sorts objects based on the Ordered and PriorityOrdered interfaces.
Ordered
A contract for objects that are assigned an order or precedence value.
OrderSourceProvider
A strategy interface for providing an alternative source of order metadata
for a given object.
OutputStream
This abstract class is the superclass of all classes representing an output
stream of bytes.
Package
Represents a Dart package within the JetLeaf reflection and
code generation system.
PackageConfigEntry
Represents a single entry in a parsed package_config.json file.
PackageIdentifier
Represents an abstraction for identifying the package that an object,
resource, or service belongs to.
PackageNames
A central collection of constant package name identifiers used
throughout the Jetleaf framework .
PackageOrderComparator
A comparator that orders classes based on their package hierarchy and origin.
Parameter
Provides reflective access to method/constructor parameter metadata.
ParameterDeclaration
Represents a parameter in a constructor or method, with metadata about
its name, type, position (named or positional), and default value.
PermissionManager
Abstract interface for elements that can have protection domains.
PrintStream
An abstract interface representing a stream for formatted text output.
PriorityOrdered
A special marker interface for Ordered objects that should be given
priority over other Ordered objects during sorting or processing.
ProtectionDomain
Represents a security boundary for code execution within a container or framework,
defining permissions, metadata, and inheritance rules for reflection-based access.
Provider <T >
A generic provider interface for supplying instances of type T.
QualifiedName
Defines a contract for objects that expose a fully-qualified, stable name
within the JetLeaf type and metadata system.
QueryParamValidator
Validates that a URI contains all required query parameters.
Queue <E >
A first-in-first-out (FIFO) queue interface implementation, mimicking Java's Queue.
Reader
Abstract class for reading character streams.
RecordDeclaration
Represents a reflected Dart record type.
RecordField
A representation of an individual field within a Dart record type in the
JetLeaf reflection system.
RecordFieldDeclaration
A representation of an individual field within a Dart record type in the
JetLeaf reflection system.
ReflectableAnnotation
Represents an annotation that has been applied to a class, method,
field, parameter, or other Dart declarations at runtime.
ReflectionUtils
Lightweight runtime reflection utility built on top of dart:mirrors.
RegexUtils
A collection of commonly used regular expressions, provided as constants.
Resolved
An annotation used to mark classes for which AOT-compatible runtime
resolvers should be generated.
Runnable
A simple contract for objects that can be executed.
RuntimeBuilder
Centralized build-time logging and execution context manager for JetLeaf.
RuntimeExecutor
Defines an interface for executing runtime operations in a Dart environment,
providing a high-level abstraction for dynamic object creation, method invocation,
and field manipulation.
RuntimeExecutorResolving
An abstract base class responsible for orchestrating the runtime resolution
of types, methods, and fields across multiple libraries.
RuntimeHint
A contract for providing runtime-level behavioral overrides to the JetLeaf
execution system.
RuntimeHintDescriptor
An abstract descriptor that represents a collection of RuntimeHint instances.
RuntimeHintProvider
A factory interface responsible for producing concrete RuntimeHint
instances.
RuntimeProvider
A runtime-backed extension of MaterialLibrary that exposes
environment-level metadata and execution capabilities.
RuntimeScanner
Defines the contract for a reflection scanner that processes Dart source
files, extracts metadata, and optionally persists output.
RuntimeScannerConfiguration
Configuration controller for reflection scanning operations in JetLeaf.
RuntimeScannerSummary
Represents a summary of the reflection scan process, containing
diagnostics and metadata such as build time and scanning context.
RuntimeUtils
Utility class for reflection-related operations in JetLeaf.
SchemeValidator
Validates that a URI contains a scheme component (e.g., "https://").
SecureSchemeValidator
Validates that a URI uses a secure scheme (https or wss by default).
Short
A wrapper class for int representing a 16-bit signed integer.
SimpleProvider <T >
Simple, immutable implementation of Provider that always returns
a pre-defined, constant value.
SinkOutputStream
A concrete implementation of OutputStream that wraps a Dart IOSink ,
allowing byte, list of bytes, and string data to be written to any underlying
sink, such as files, sockets, or stdout.
Source
Abstract base class for all reflection metadata that can be annotated.
SourceDeclaration
A declaration that originates directly from source-level Dart code .
SourceLibrary
A first-class representation of a Dart library’s source code within
the JetLeaf framework. SourceLibrary is the canonical source-level library abstraction in
JetLeaf. It bridges file systems, packages, analyzers, and generators while
remaining lightweight, stable, and environment-agnostic.
Stack <E >
A last-in-first-out (LIFO) stack implementation, mimicking Java's Stack.
StandardDoubleStream
Private implementation of DoubleStream that wraps an Iterable of doubles.
StandardGenericStream <T >
Implementation of GenericStream that wraps an Iterable and provides
some basic stream operations.
StandardIntStream
Private implementation of IntStream .
StreamBuilder <T >
A mutable builder for a GenericStream .
StreamSupport
Low-level utility methods for creating and manipulating streams.
StringBuilder
A mutable sequence of characters similar to Java's StringBuilder.
StringInputStream
A character-based input stream backed by an encoded String .
StringReader
A Reader implementation that reads characters from a String buffer.
SuppliedNamedLocalThread <T >
A NamedLocalThread that provides an initial value using a Supplier function.
SynchronizedLock
A reentrant async lock for critical section execution.
SystemDetector
Strategy interface for detecting and creating SystemEnvironment instances.
SystemProperties
The SystemProperties interface provides a clean, method-based API
for querying the runtime environment. Unlike direct property access,
all system state is exposed via methods to enforce immutability
and ensure consistent naming conventions.
Thread <T >
Emulates Java's Thread class using Dart's Isolate.
ThreadMessage
Wrapper message passed to the Isolate's entry point function.
ToStringOptions
Configuration options for customizing toString output in JetLeaf objects.
UnresolvedClass
Represents a class whose type could not be fully resolved at runtime.
UriTemplate
A utility class for defining and working with URI templates that include
path variables (e.g., /users/{id}/orders/{orderId}).
UriValidator
An abstract validator for URI/URL validation.
Url
Represents a Uniform Resource Locator (URL) and provides methods to parse,
construct, and open connections to the referenced resource.
UrlConnection
Represents a communication link between the application and a Url .
Uuid
A powerful, secure implementation of Universally Unique Identifiers (UUIDs)
following RFC 4122 specifications.
ValueChanged <T >
Represents a change in a single observable value.
Version
Represents a semantic version in Jetleaf with major, minor, and patch
components.
VersionRange
Represents a simple semantic version range in Jetleaf .
Void
Abstract base class representing a marker or placeholder type in the
JetLeaf type system.
Writer
Abstract class for writing to character streams.
ZonedDateTime
Represents a date-time with timezone information.
ZoneId
Represents a time zone identifier, abstracting the concept of region-based
or offset-based zone IDs (e.g., 'UTC', 'America/New_York').
Enums
DomainPermission
Enumeration of reflection-based permissions for secure access to class metadata,
fields, methods, constructors, and annotations within a container or framework.
ListChangeType
Represents the type of change that occurs in a List.
MapChangeType
Represents the type of change that occurs in a Map.
TypeKind
Enumerates the different kinds of Dart types recognized by JetLeaf’s
reflection and type resolution system.
Constants
MUST_AVOID_PACKAGE
→ const String
Constant representing the package name that must be avoided during import
checks. Used by forgetPackage to detect and filter forbidden references.
Functions
forgetPackage (String text )
→ bool
Returns true if the provided text contains a reference to a package
that should be excluded.
getNonNecessaryPackages ()
→ List <String >
Returns a list of package names that are considered non-essential for
runtime analysis and should generally be excluded from scanning.
hashCode (Object current )
→ int
Computes a deep hash code for an object.
optional <T > (T? value )
→ Optional <T >
Wraps the given value in an Optional container.
resolvePublicDartType (String uri , String className , [DeclarationMirror ? mirror ])
→ Type ?
Resolves a public Dart platform type using a library URI and class name.
rootAssetLoader (String packageName )
→ AssetLoaderInterface
Creates an asset bundler for a user-defined package.
runScan ({Directory ? source , RuntimeScannerConfiguration ? config , bool forceLoadLibraries = false , OnLogged ? onInfo , OnLogged ? onWarning , OnLogged ? onError , List <String > args = const [] , RuntimeScanner ? configuredScanner , bool overrideConfig = false })
→ Future <RuntimeScannerSummary >
Executes a full application runtime scan , builds a runtime context,
and registers it globally.
runTestScan ({List <String > packagesToExclude = const [] , List <String > filesToLoad = const [] , RuntimeScannerConfiguration ? config , OnLogged ? onInfo , OnLogged ? onWarning , OnLogged ? onError , List <String > args = const [] , Directory ? source , RuntimeScanner ? configuredScanner })
→ Future <RuntimeScannerSummary >
Executes a mock runtime scan and registers the resulting runtime
context for testing and validation purposes.
synchronized <T > (Object monitor , T action () )
→ T
Runs the given action in a critical section, ensuring only one
execution at a time per monitor object.
synchronizedAsync <T > (Object monitor , FutureOr <T > action () )
→ FutureOr <T >
Runs the given action in a critical section, ensuring only one
execution at a time per monitor object.
tryWith <T extends Closeable > (T resource , TryWithAction<T > action )
→ Future <void >
Utility for automatically closing a resource after use.
Typedefs
Accumulator <T , U >
= U Function(U , T )
A function used to accumulate values in reduction operations.
AssetResourceContentDetector
= bool Function(Object source )
A function signature for detecting whether a given source should be
treated as content rather than a file path.
AssetResourceExtensionStrategy
= String ? Function(Object source )
A function signature for determining the extension of an AssetResource .
Bool
= bool
An alias for the built-in bool type.
BoolCollection
= List <Bool >
A list of boolean values using the Bool alias.
BoolSet
= Set <Bool >
A set of unique boolean values using the Bool alias.
ConditionTester <T >
= bool Function(T value )
A typedef for a predicate function that tests a condition on a value of type T.
Consumer <T >
= void Function(T value )
A function that consumes a value of type T without returning anything.
DataMapper <T , U >
= U Function(T value )
A function that transforms a value from type T to type U.
DateTimeCollection
= List <DateTime >
A list of DateTime values.
DateTimeSet
= Set <DateTime >
A set of unique DateTime values.
DurationCollection
= List <Duration >
A list of Duration values.
DurationSet
= Set <Duration >
A set of unique Duration values.
ExceptionSupplier
= Object Function()
A function that returns an exception object to be thrown when needed.
Int
= int
A shorthand alias for an integer value.
IntCollection
= List <Int >
A list of integers using the Int alias.
IntSet
= Set <Int >
A set of unique integers using the Int alias.
JsonMap
= Map <String , dynamic >
A JSON-like structure represented as a Map<String, dynamic>.
JsonMapCollection
= List <JsonMap >
A list of JSON-like maps, useful for handling multiple entities.
JsonString
= Map <String , String >
A map of string keys and string values representing simple string-based JSON data.
MockLibraryGeneratorFactory
= LibraryGenerator Function(MockLibraryGeneratorParams )
Signature for creating custom mock library generators.
OnLogged
= void Function(String message , bool overwrite )
Signature for logging callbacks used to report runtime scanning messages.
Predicate <T >
= Bool Function(T value )
A function that takes a value of type T and returns a boolean.
StringCollection
= List <String >
A list of strings.
StringSet
= Set <String >
A set of unique strings.
Supplier <T >
= T Function()
A function that supplies a value of type T, typically lazily or on-demand.
ThrowingSupplier <T >
= T Function()
A functional interface that supplies a value and may throw an exception.
TryOutsideIsolate
= bool Function(File file , Uri uri )
Signature for a callback used to determine whether a file should be
processed outside an isolate.