New rule: LongLineRule

.yanagiba

@@ -1,6 +1,7 @@
 lint:
   rule-configurations:
     - NESTED_CODE_BLOCK_DEPTH: 6
+    - LONG_LINE: 120
   severity-thresholds:
     - critical: 0
     - major: 0

Documentation/Rules/Readability.md

@@ -127,3 +127,35 @@ func example(
 ##### References:
 
 Fowler, Martin (1999). *Refactoring: Improving the design of existing code.* Addison Wesley.
+
+
+## Long Line
+
+<dl>
+<dt>Identifier</dt>
+<dd>long_line</dd>
+<dt>File name</dt>
+<dd>LongLineRule.swift</dd>
+<dt>Severity</dt>
+<dd>Minor</dd>
+<dt>Category</dt>
+<dd>Readability</dd>
+</dl>
+
+When a line of code is very long, it largely harms the readability.
+Break long lines of code into multiple lines.
+
+##### Thresholds:
+
+<dl>
+<dt>LONG_LINE</dt>
+<dd>The long line reporting threshold, default value is 100.</dd>
+</dl>
+
+##### Examples:
+
+###### Example 1
+
+```
+let a012345678901234567890123456789...1234567890123456789012345678901234567890123456789
+```

Documentation/Rules/Readability_CN.md

@@ -127,3 +127,35 @@ func example(
 ##### References:
 
 Fowler, Martin (1999). *Refactoring: Improving the design of existing code.* Addison Wesley.
+
+
+## Long Line
+
+<dl>
+<dt>标识名</dt>
+<dd>long_line</dd>
+<dt>文件名</dt>
+<dd>LongLineRule.swift</dd>
+<dt>严重级别</dt>
+<dd>Minor</dd>
+<dt>分类</dt>
+<dd>Readability</dd>
+</dl>
+
+When a line of code is very long, it largely harms the readability.
+Break long lines of code into multiple lines.
+
+##### Thresholds:
+
+<dl>
+<dt>LONG_LINE</dt>
+<dd>The long line reporting threshold, default value is 100.</dd>
+</dl>
+
+##### Examples:
+
+###### Example 1
+
+```
+let a012345678901234567890123456789...1234567890123456789012345678901234567890123456789
+```

Documentation/Rules/Readability_JP.md

@@ -127,3 +127,35 @@ func example(
 ##### References:
 
 Fowler, Martin (1999). *Refactoring: Improving the design of existing code.* Addison Wesley.
+
+
+## Long Line
+
+<dl>
+<dt>識別子</dt>
+<dd>long_line</dd>
+<dt>ファイル名</dt>
+<dd>LongLineRule.swift</dd>
+<dt>激しさ</dt>
+<dd>Minor</dd>
+<dt>分類</dt>
+<dd>Readability</dd>
+</dl>
+
+When a line of code is very long, it largely harms the readability.
+Break long lines of code into multiple lines.
+
+##### Thresholds:
+
+<dl>
+<dt>LONG_LINE</dt>
+<dd>The long line reporting threshold, default value is 100.</dd>
+</dl>
+
+##### Examples:
+
+###### Example 1
+
+```
+let a012345678901234567890123456789...1234567890123456789012345678901234567890123456789
+```

Sources/Lint/Rule/LongLineRule.swift

@@ -0,0 +1,61 @@
+/*
+   Copyright 2017 Ryuichi Saito, LLC and the Yanagiba project contributors
+
+   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
+
+       http://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 Foundation
+
+class LongLineRule : RuleBase, SourceCodeRule {
+  static let ThresholdKey = "LONG_LINE"
+  static let DefaultThreshold = 100
+
+  let name = "Long Line"
+  var description: String? {
+    return """
+    When a line of code is very long, it largely harms the readability.
+    Break long lines of code into multiple lines.
+    """
+  }
+  var examples: [String]? {
+    return [
+      "let a012345678901234567890123456789...1234567890123456789012345678901234567890123456789",
+    ]
+  }
+  var thresholds: [String: String]? {
+    return [
+      LongLineRule.ThresholdKey:
+        "The long line reporting threshold, default value is \(LongLineRule.DefaultThreshold)."
+    ]
+  }
+  let severity = Issue.Severity.minor
+  let category = Issue.Category.readability
+
+  private func getThreshold(of lineNumber: Int) -> Int {
+    return getConfiguration(
+      forKey: LongLineRule.ThresholdKey,
+      atLineNumber: lineNumber,
+      orDefault: LongLineRule.DefaultThreshold)
+  }
+
+  func inspect(line: String, lineNumber: Int) {
+    let threshold = getThreshold(of: lineNumber)
+    let lineCount = line.count
+    guard lineCount > threshold else {
+      return
+    }
+    emitIssue(
+      lineNumber,
+      description: "Line with \(lineCount) characters exceeds limit of \(threshold)")
+  }
+}

Sources/Lint/RuleSet.swift

@@ -35,6 +35,7 @@ public struct RuleSet {
     RedundantVariableDeclarationKeywordRule(),
     RedundantEnumCaseStringValueRule(),
     TooManyParametersRule(),
+    LongLineRule(),
   ]
 
   public static var ruleIdentifiers: [String] {

Sources/Lint/SourceCodeRule.swift

@@ -24,15 +24,40 @@ protocol SourceCodeRule : Rule {
 }
 
 extension SourceCodeRule where Self : RuleBase {
+  private var lines: [String] {
+    guard let astContext = astContext else {
+      return []
+    }
+
+    return astContext.sourceFile.content.components(separatedBy: .newlines)
+  }
+
   func inspect(_ astContext: ASTContext, configurations: [String: Any]? = nil) {
     self.astContext = astContext
     self.configurations = configurations
 
-    let sourceContent = astContext.sourceFile.content
-
-    let lines = sourceContent.components(separatedBy: .newlines)
     for (lineNumber, line) in lines.enumerated() {
         inspect(line: line, lineNumber: lineNumber + 1)
     }
   }
+
+  func emitIssue(
+    _ lineNumber: Int,
+    description: String,
+    correction: Correction? = nil
+  ) {
+    guard lineNumber > 0 && lineNumber <= lines.count,
+      let path = astContext?.sourceFile.path
+    else {
+      return
+    }
+
+    let lineIndex = lineNumber - 1
+    let line = lines[lineIndex]
+    let sourceRange = SourceRange(
+      start: SourceLocation(path: path, line: lineNumber, column: 1),
+      end: SourceLocation(path: path, line: lineNumber, column: line.count)
+    )
+    emitIssue(sourceRange, description: description, correction: correction)
+  }
 }

Tests/RuleTests/LongLineRuleTests.swift

@@ -0,0 +1,72 @@
+/*
+   Copyright 2017 Ryuichi Saito, LLC and the Yanagiba project contributors
+
+   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
+
+       http://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 XCTest
+
+@testable import Lint
+
+class LongLineRuleTests : XCTestCase {
+  func testShortText() {
+    XCTAssertTrue(getIssues(from: """
+    let a
+    b
+    """).isEmpty)
+  }
+
+  func testLongText() {
+    let issues = getIssues(from: """
+    let a = b
+    foo() {}
+    """)
+    XCTAssertEqual(issues.count, 2)
+    let issue0 = issues[0]
+    XCTAssertEqual(issue0.ruleIdentifier, "long_line")
+    XCTAssertEqual(issue0.description, "Line with 9 characters exceeds limit of 5")
+    XCTAssertEqual(issue0.category, .readability)
+    XCTAssertEqual(issue0.severity, .minor)
+    let range0 = issue0.location
+    XCTAssertEqual(range0.start.path, "test/test")
+    XCTAssertEqual(range0.start.line, 1)
+    XCTAssertEqual(range0.start.column, 1)
+    XCTAssertEqual(range0.end.path, "test/test")
+    XCTAssertEqual(range0.end.line, 1)
+    XCTAssertEqual(range0.end.column, 9)
+    let issue1 = issues[1]
+    XCTAssertEqual(issue1.ruleIdentifier, "long_line")
+    XCTAssertEqual(issue1.description, "Line with 8 characters exceeds limit of 5")
+    XCTAssertEqual(issue1.category, .readability)
+    XCTAssertEqual(issue1.severity, .minor)
+    let range1 = issue1.location
+    XCTAssertEqual(range1.start.path, "test/test")
+    XCTAssertEqual(range1.start.line, 2)
+    XCTAssertEqual(range1.start.column, 1)
+    XCTAssertEqual(range1.end.path, "test/test")
+    XCTAssertEqual(range1.end.line, 2)
+    XCTAssertEqual(range1.end.column, 8)
+  }
+
+  private func getIssues(from content: String) -> [Issue] {
+    return content.inspect(
+      withRule: LongLineRule(),
+      configurations: [LongLineRule.ThresholdKey: 5]
+    )
+  }
+
+  static var allTests = [
+    ("testShortText", testShortText),
+    ("testLongText", testLongText),
+  ]
+}

Tests/RuleTests/XCTestManifests.swift

@@ -38,6 +38,7 @@ public func allTests() -> [XCTestCaseEntry] {
     testCase(RedundantVariableDeclarationKeywordRuleTests.allTests),
     testCase(RedundantEnumCaseStringValueRuleTests.allTests),
     testCase(TooManyParametersRuleTests.allTests),
+    testCase(LongLineRuleTests.allTests),
   ]
 }
 #endif