Add linter for lines of code

example/analysis_options.yaml

@@ -10,3 +10,5 @@ custom_lint:
       max_complexity: 4
     - number_of_parameters:
       max_parameters: 2
+    - function_lines_of_code:
+      max_lines: 50

example/test/lines_of_code_test.dart

@@ -0,0 +1,59 @@
+import 'package:test/test.dart';
+
+/// Check number of lines fail
+///
+/// `function_lines_of_code: max_lines`
+/// expect_lint: function_lines_of_code
+void linesOfCode() {
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+  test("addition", () {
+    expect(1 + 1, equals(2));
+  });
+}

lib/cyclomatic_complexity/cyclomatic_complexity_metric.dart → lib/lints/cyclomatic_complexity/cyclomatic_complexity_metric.dart

@@ -1,7 +1,7 @@
 import 'package:analyzer/error/listener.dart';
 import 'package:custom_lint_builder/custom_lint_builder.dart';
-import 'package:solid_lints/cyclomatic_complexity/models/cyclomatic_complexity_parameters.dart';
-import 'package:solid_lints/cyclomatic_complexity/visitor/cyclomatic_complexity_flow_visitor.dart';
+import 'package:solid_lints/lints/cyclomatic_complexity/models/cyclomatic_complexity_parameters.dart';
+import 'package:solid_lints/lints/cyclomatic_complexity/visitor/cyclomatic_complexity_flow_visitor.dart';
 import 'package:solid_lints/models/metric_rule.dart';
 
 /// A Complexity metric checks content of block and detects more easier solution

lib/cyclomatic_complexity/visitor/cyclomatic_complexity_flow_visitor.dart → lib/lints/cyclomatic_complexity/visitor/cyclomatic_complexity_flow_visitor.dart

@@ -1,4 +1,4 @@
-//MIT License
+// MIT License
 //
 // Copyright (c) 2020-2021 Dart Code Checker team
 //

lib/lints/function_lines_of_code/function_lines_of_code_metric.dart

@@ -0,0 +1,40 @@
+import 'package:analyzer/error/listener.dart';
+import 'package:custom_lint_builder/custom_lint_builder.dart';
+import 'package:solid_lints/lints/function_lines_of_code/models/function_lines_of_code_parameters.dart';
+import 'package:solid_lints/lints/function_lines_of_code/visitor/function_lines_of_code_visitor.dart';
+import 'package:solid_lints/models/metric_rule.dart';
+
+/// A number of lines metric which checks whether we didn't exceed
+/// the maximum allowed number of lines for a file
+class FunctionLinesOfCodeMetric extends DartLintRule {
+  /// The [LintCode] of this lint rule that represents the error if number of
+  /// parameters reaches the maximum value.
+  static const lintName = 'function_lines_of_code';
+
+  /// Configuration for number of parameters metric rule.
+  final MetricRule<FunctionLinesOfCodeParameters> config;
+
+  /// Creates a new instance of [FunctionLinesOfCodeMetric].
+  FunctionLinesOfCodeMetric(this.config) : super(code: config.lintCode);
+
+  @override
+  void run(
+    CustomLintResolver resolver,
+    ErrorReporter reporter,
+    CustomLintContext context,
+  ) {
+    final visitor = FunctionLinesOfCodeVisitor(resolver.lineInfo);
+
+    context.registry.addDeclaration((node) {
+      node.visitChildren(visitor);
+
+      if (visitor.linesWithCode.length > config.parameters.maxLines) {
+        reporter.reportErrorForOffset(
+          code,
+          node.firstTokenAfterCommentAndMetadata.offset,
+          node.end,
+        );
+      }
+    });
+  }
+}

lib/lints/function_lines_of_code/models/function_lines_of_code_parameters.dart

@@ -0,0 +1,19 @@
+/// A data model class that represents the "source lines of code" input
+/// parameters.
+class FunctionLinesOfCodeParameters {
+  /// Maximum number of lines
+  final int maxLines;
+
+  static const _defaultMaxLines = 200;
+
+  /// Constructor for [FunctionLinesOfCodeParameters] model
+  const FunctionLinesOfCodeParameters({
+    required this.maxLines,
+  });
+
+  /// Method for creating from json data
+  factory FunctionLinesOfCodeParameters.fromJson(Map<String, Object?> json) =>
+      FunctionLinesOfCodeParameters(
+        maxLines: json['max_lines'] as int? ?? _defaultMaxLines,
+      );
+}

lib/lints/function_lines_of_code/visitor/function_lines_of_code_visitor.dart

@@ -0,0 +1,69 @@
+// MIT License
+//
+// Copyright (c) 2020-2021 Dart Code Checker team
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/token.dart';
+import 'package:analyzer/dart/ast/visitor.dart';
+import 'package:analyzer/source/line_info.dart';
+
+/// The AST visitor that will find lines with code.
+class FunctionLinesOfCodeVisitor extends RecursiveAstVisitor<void> {
+  final LineInfo _lineInfo;
+
+  final _linesWithCode = <int>{};
+
+  /// Returns the array with indices of lines with code.
+  Iterable<int> get linesWithCode => _linesWithCode;
+
+  /// Creates a new instance of [FunctionLinesOfCodeVisitor].
+  FunctionLinesOfCodeVisitor(this._lineInfo);
+
+  @override
+  void visitBlockFunctionBody(BlockFunctionBody node) {
+    _collectFunctionBodyData(
+      node.block.leftBracket.next,
+      node.block.rightBracket,
+    );
+    super.visitBlockFunctionBody(node);
+  }
+
+  @override
+  void visitExpressionFunctionBody(ExpressionFunctionBody node) {
+    _collectFunctionBodyData(
+      node.expression.beginToken.previous,
+      node.expression.endToken.next,
+    );
+    super.visitExpressionFunctionBody(node);
+  }
+
+  void _collectFunctionBodyData(Token? firstToken, Token? lastToken) {
+    var token = firstToken;
+    while (token != lastToken && token != null) {
+      if (!token.isSynthetic) {
+        _linesWithCode.add(_lineInfo.getLocation(token.offset).lineNumber);
+      }
+
+      token = token.next;
+    }
+  }
+}

lib/number_of_parameters/number_of_parameters_metric.dart → lib/lints/number_of_parameters/number_of_parameters_metric.dart

@@ -1,8 +1,8 @@
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/error/listener.dart';
 import 'package:custom_lint_builder/custom_lint_builder.dart';
+import 'package:solid_lints/lints/number_of_parameters/models/number_of_parameters_parameters.dart';
 import 'package:solid_lints/models/metric_rule.dart';
-import 'package:solid_lints/number_of_parameters/models/number_of_parameters_parameters.dart';
 
 /// A number of parameters metric which checks whether we didn't exceed
 /// the maximum allowed number of parameters for a function or a method

lib/solid_lints.dart

@@ -1,11 +1,13 @@
 library solid_metrics;
 
 import 'package:custom_lint_builder/custom_lint_builder.dart';
-import 'package:solid_lints/cyclomatic_complexity/cyclomatic_complexity_metric.dart';
-import 'package:solid_lints/cyclomatic_complexity/models/cyclomatic_complexity_parameters.dart';
+import 'package:solid_lints/lints/cyclomatic_complexity/cyclomatic_complexity_metric.dart';
+import 'package:solid_lints/lints/cyclomatic_complexity/models/cyclomatic_complexity_parameters.dart';
+import 'package:solid_lints/lints/function_lines_of_code/function_lines_of_code_metric.dart';
+import 'package:solid_lints/lints/function_lines_of_code/models/function_lines_of_code_parameters.dart';
+import 'package:solid_lints/lints/number_of_parameters/models/number_of_parameters_parameters.dart';
+import 'package:solid_lints/lints/number_of_parameters/number_of_parameters_metric.dart';
 import 'package:solid_lints/models/metric_rule.dart';
-import 'package:solid_lints/number_of_parameters/models/number_of_parameters_parameters.dart';
-import 'package:solid_lints/number_of_parameters/number_of_parameters_metric.dart';
 
 /// creates plugin
 PluginBase createPlugin() => _SolidLints();
@@ -42,6 +44,19 @@ class _SolidLints extends PluginBase {
       rules.add(NumberOfParametersMetric(numberOfParameters));
     }
 
+    final functionLinesOfCode = MetricRule<FunctionLinesOfCodeParameters>(
+      configs: configs,
+      name: FunctionLinesOfCodeMetric.lintName,
+      factory: FunctionLinesOfCodeParameters.fromJson,
+      problemMessage: (value) => ''
+          'The maximum allowed number of lines is ${value.maxLines}. '
+          'Try splitting this function into smaller parts.',
+    );
+
+    if (functionLinesOfCode.enabled) {
+      rules.add(FunctionLinesOfCodeMetric(functionLinesOfCode));
+    }
+
     return rules;
   }
 }