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cherrypick/cherrypick_generator/lib/src/bind_spec.dart
2025-08-08 23:24:05 +03:00

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//
// Copyright 2021 Sergey Penkovsky (sergey.penkovsky@gmail.com)
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// https://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
import 'package:analyzer/dart/element/element.dart';
import 'bind_parameters_spec.dart';
import 'metadata_utils.dart';
import 'exceptions.dart';
import 'type_parser.dart';
import 'annotation_validator.dart';
enum BindingType {
instance,
provide;
}
/// ---------------------------------------------------------------------------
/// BindSpec -- describes a binding specification generated for a dependency.
///
/// ENGLISH
/// Represents all the data necessary to generate a DI binding for a single
/// method in a module class. Each BindSpec corresponds to one public method
/// and contains information about its type, provider method, lifecycle (singleton),
/// parameters (with their annotations), binding strategy (instance/provide),
/// asynchronous mode, and named keys. It is responsible for generating the
/// correct Dart code to register this binding with the DI container, in both
/// sync and async cases, with and without named or runtime arguments.
///
/// RUSSIAN
/// Описывает параметры для создания одного биндинга зависимости (binding spec).
/// Каждый биндинг соответствует одному публичному методу класса-модуля и
/// содержит всю информацию для генерации кода регистрации этого биндинга в
/// DI-контейнере: тип возвращаемой зависимости, имя метода, параметры, аннотации
/// (@singleton, @named, @instance, @provide), асинхронность, признак runtime
/// аргументов и др. Генерирует правильный Dart-код для регистрации биндера.
/// ---------------------------------------------------------------------------
class BindSpec {
/// The type this binding provides (e.g. SomeService)
/// Тип, который предоставляет биндинг (например, SomeService)
final String returnType;
/// Method name that implements the binding
/// Имя метода, который реализует биндинг
final String methodName;
/// Optional name for named dependency (from @named)
/// Необязательное имя, для именованной зависимости (используется с @named)
final String? named;
/// Whether the dependency is a singleton (@singleton annotation)
/// Является ли зависимость синглтоном (имеется ли аннотация @singleton)
final bool isSingleton;
/// List of method parameters to inject dependencies with
/// Список параметров, которые требуются методу для внедрения зависимостей
final List<BindParameterSpec> parameters;
/// Binding type: 'instance' or 'provide' (@instance or @provide)
final BindingType bindingType; // 'instance' | 'provide'
/// True if the method is asynchronous and uses instance binding (Future)
final bool isAsyncInstance;
/// True if the method is asynchronous and uses provide binding (Future)
final bool isAsyncProvide;
/// True if the binding method accepts runtime "params" argument (@params)
final bool hasParams;
BindSpec({
required this.returnType,
required this.methodName,
required this.isSingleton,
required this.parameters,
this.named,
required this.bindingType,
required this.isAsyncInstance,
required this.isAsyncProvide,
required this.hasParams,
});
/// -------------------------------------------------------------------------
/// generateBind
///
/// ENGLISH
/// Generates a line of Dart code registering the binding with the DI framework.
/// Produces something like:
/// bind<Type>().toProvide(() => method(args)).withName('name').singleton();
/// Indent parameter allows formatted multiline output.
///
/// RUSSIAN
/// Формирует dart-код для биндинга, например:
/// bind<Type>().toProvide(() => method(args)).withName('name').singleton();
/// Параметр [indent] задаёт отступ для красивого форматирования кода.
/// -------------------------------------------------------------------------
String generateBind(int indent) {
final indentStr = ' ' * indent;
final provide = _generateProvideClause(indent);
final postfix = _generatePostfix();
// Create the full single-line version first
final singleLine = '${indentStr}bind<$returnType>()$provide$postfix;';
// Check if we need multiline formatting
final needsMultiline = singleLine.length > 80 || provide.contains('\n');
if (!needsMultiline) {
return singleLine;
}
// For multiline formatting, check if we need to break after bind<Type>()
if (provide.contains('\n')) {
// Provider clause is already multiline
if (postfix.isNotEmpty) {
// If there's a postfix, break after bind<Type>()
final multilinePostfix = _generateMultilinePostfix(indent);
return '${indentStr}bind<$returnType>()'
'\n${' ' * (indent + 4)}$provide'
'$multilinePostfix;';
} else {
// No postfix, keep bind<Type>() with provide start
return '${indentStr}bind<$returnType>()$provide;';
}
} else {
// Simple multiline: break after bind<Type>()
if (postfix.isNotEmpty) {
final multilinePostfix = _generateMultilinePostfix(indent);
return '${indentStr}bind<$returnType>()'
'\n${' ' * (indent + 4)}$provide'
'$multilinePostfix;';
} else {
return '${indentStr}bind<$returnType>()'
'\n${' ' * (indent + 4)}$provide;';
}
}
}
// Internal method: decides how the provide clause should be generated by param kind.
String _generateProvideClause(int indent) {
if (hasParams) return _generateWithParamsProvideClause(indent);
return _generatePlainProvideClause(indent);
}
/// EN / RU: Supports runtime parameters (@params).
String _generateWithParamsProvideClause(int indent) {
// Safe variable name for parameters.
const paramVar = 'args';
final fnArgs = parameters.map((p) => p.generateArg(paramVar)).join(', ');
// Use multiline format only if args are long or contain newlines
final multiLine = fnArgs.length > 60 || fnArgs.contains('\n');
switch (bindingType) {
case BindingType.instance:
throw StateError(
'Internal error: _generateWithParamsProvideClause called for @instance binding with @params.');
//return isAsyncInstance
// ? '.toInstanceAsync(($fnArgs) => $methodName($fnArgs))'
// : '.toInstance(($fnArgs) => $methodName($fnArgs))';
case BindingType.provide:
if (isAsyncProvide) {
return multiLine
? '.toProvideAsyncWithParams(\n${' ' * (indent + 2)}($paramVar) => $methodName($fnArgs))'
: '.toProvideAsyncWithParams(($paramVar) => $methodName($fnArgs))';
} else {
return multiLine
? '.toProvideWithParams(\n${' ' * (indent + 2)}($paramVar) => $methodName($fnArgs))'
: '.toProvideWithParams(($paramVar) => $methodName($fnArgs))';
}
}
}
/// EN / RU: Supports only injected dependencies, not runtime (@params).
String _generatePlainProvideClause(int indent) {
final argsStr = parameters.map((p) => p.generateArg()).join(', ');
// Check if we need multiline formatting based on total line length
final singleLineCall = '$methodName($argsStr)';
final needsMultiline =
singleLineCall.length >= 45 || argsStr.contains('\n');
switch (bindingType) {
case BindingType.instance:
return isAsyncInstance
? '.toInstanceAsync($methodName($argsStr))'
: '.toInstance($methodName($argsStr))';
case BindingType.provide:
if (isAsyncProvide) {
if (needsMultiline) {
final lambdaIndent =
(isSingleton || named != null) ? indent + 6 : indent + 2;
final closingIndent =
(isSingleton || named != null) ? indent + 4 : indent;
return '.toProvideAsync(\n${' ' * lambdaIndent}() => $methodName($argsStr),\n${' ' * closingIndent})';
} else {
return '.toProvideAsync(() => $methodName($argsStr))';
}
} else {
if (needsMultiline) {
final lambdaIndent =
(isSingleton || named != null) ? indent + 6 : indent + 2;
final closingIndent =
(isSingleton || named != null) ? indent + 4 : indent;
return '.toProvide(\n${' ' * lambdaIndent}() => $methodName($argsStr),\n${' ' * closingIndent})';
} else {
return '.toProvide(() => $methodName($argsStr))';
}
}
}
}
/// EN / RU: Adds .withName and .singleton if needed.
String _generatePostfix() {
final namePart = named != null ? ".withName('$named')" : '';
final singletonPart = isSingleton ? '.singleton()' : '';
return '$namePart$singletonPart';
}
/// EN / RU: Generates multiline postfix with proper indentation.
String _generateMultilinePostfix(int indent) {
final parts = <String>[];
if (named != null) {
parts.add(".withName('$named')");
}
if (isSingleton) {
parts.add('.singleton()');
}
if (parts.isEmpty) return '';
return parts.map((part) => '\n${' ' * (indent + 4)}$part').join('');
}
/// -------------------------------------------------------------------------
/// fromMethod
///
/// ENGLISH
/// Creates a BindSpec from a module class method by analyzing its return type,
/// annotations, list of parameters (with their own annotations), and async-ness.
/// Throws if a method does not have the required @instance() or @provide().
///
/// RUSSIAN
/// Создаёт спецификацию биндинга (BindSpec) из метода класса-модуля, анализируя
/// возвращаемый тип, аннотации, параметры (и их аннотации), а также факт
/// асинхронности. Если нет @instance или @provide — кидает ошибку.
/// -------------------------------------------------------------------------
static BindSpec fromMethod(MethodElement method) {
try {
// Validate method annotations
AnnotationValidator.validateMethodAnnotations(method);
// Parse return type using improved type parser
final parsedReturnType = TypeParser.parseType(method.returnType, method);
final methodName = method.displayName;
// Check for @singleton annotation.
final isSingleton = MetadataUtils.anyMeta(method.metadata, 'singleton');
// Get @named value if present.
final named = MetadataUtils.getNamedValue(method.metadata);
// Parse each method parameter.
final params = <BindParameterSpec>[];
bool hasParams = false;
for (final p in method.parameters) {
final typeStr = p.type.getDisplayString();
final paramNamed = MetadataUtils.getNamedValue(p.metadata);
final isParams = MetadataUtils.anyMeta(p.metadata, 'params');
if (isParams) hasParams = true;
params.add(BindParameterSpec(typeStr, paramNamed, isParams: isParams));
}
// Determine bindingType: @instance or @provide.
final hasInstance = MetadataUtils.anyMeta(method.metadata, 'instance');
final hasProvide = MetadataUtils.anyMeta(method.metadata, 'provide');
if (!hasInstance && !hasProvide) {
throw AnnotationValidationException(
'Method must be marked with either @instance() or @provide() annotation',
element: method,
suggestion:
'Add @instance() for direct instances or @provide() for factory methods',
context: {
'method_name': methodName,
'return_type': parsedReturnType.displayString,
},
);
}
final bindingType =
hasInstance ? BindingType.instance : BindingType.provide;
// PROHIBIT @params with @instance bindings!
if (bindingType == BindingType.instance && hasParams) {
throw AnnotationValidationException(
'@params() (runtime arguments) cannot be used together with @instance()',
element: method,
suggestion: 'Use @provide() instead if you want runtime arguments',
context: {
'method_name': methodName,
'binding_type': 'instance',
'has_params': hasParams,
},
);
}
// Set async flags based on parsed type
final isAsyncInstance =
bindingType == BindingType.instance && parsedReturnType.isFuture;
final isAsyncProvide =
bindingType == BindingType.provide && parsedReturnType.isFuture;
return BindSpec(
returnType: parsedReturnType.codeGenType,
methodName: methodName,
isSingleton: isSingleton,
named: named,
parameters: params,
bindingType: bindingType,
isAsyncInstance: isAsyncInstance,
isAsyncProvide: isAsyncProvide,
hasParams: hasParams,
);
} catch (e) {
if (e is CherryPickGeneratorException) {
rethrow;
}
throw CodeGenerationException(
'Failed to create BindSpec from method "${method.displayName}"',
element: method,
suggestion:
'Check that the method has valid annotations and return type',
context: {
'method_name': method.displayName,
'return_type': method.returnType.getDisplayString(),
'error': e.toString(),
},
);
}
}
}