add checkstyle reporter

CHANGELOG.md

@@ -8,7 +8,10 @@
 
 ##### Enhancements
 
-* None.
+* Add `checkstyle` reporter to generate XML reports in the Checkstyle 4.3
+  format.
+  [JP Simard](https://github.com/jpsim)
+  [#277](https://github.com/realm/SwiftLint/issues/277)
 
 ##### Bug Fixes
 

README.md

@@ -133,7 +133,7 @@ variable_name_max_length:
 variable_name_min_length:
   - 3 # warning
   - 2 # error
-reporter: "csv" # reporter type (xcode, json, csv)
+reporter: "csv" # reporter type (xcode, json, csv, checkstyle)
 ```
 
 ### Auto-correct

Source/SwiftLintFramework/Models/Configuration.swift

@@ -25,7 +25,7 @@ public struct Configuration {
     public let disabledRules: [String] // disabled_rules
     public let included: [String]      // included
     public let excluded: [String]      // excluded
-    public let reporter: String        // reporter (xcode, json, csv)
+    public let reporter: String        // reporter (xcode, json, csv, checkstyle)
     public let rules: [Rule]
 
     public var reporterFromString: Reporter.Type {
@@ -36,6 +36,8 @@ public struct Configuration {
             return JSONReporter.self
         case CSVReporter.identifier:
             return CSVReporter.self
+        case CheckstyleReporter.identifier:
+            return CheckstyleReporter.self
         default:
             fatalError("no reporter with identifier '\(reporter)' available.")
         }

Source/SwiftLintFramework/Reporters/CheckstyleReporter.swift

@@ -0,0 +1,33 @@
+//
+//  CheckstyleReporter.swift
+//  SwiftLint
+//
+//  Created by JP Simard on 12/25/15.
+//  Copyright © 2015 Realm. All rights reserved.
+//
+
+import Foundation
+
+public struct CheckstyleReporter: Reporter {
+    public static let identifier = "checkstyle"
+    public static let isRealtime = false
+
+    public var description: String {
+        return "Reports violations as Checkstyle XML."
+    }
+
+    public static func generateReport(violations: [StyleViolation]) -> String {
+        var report = "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n<checkstyle version=\"4.3\">"
+        report += violations.map { violation in
+            let fileName = violation.location.file ?? "<nopath>"
+            return "\n\t<file name=\"\(fileName)\">\n" +
+                "\t\t<error line=\"\(violation.location.line ?? 0)\" " +
+                "column=\"\(violation.location.character ?? 0)\" " +
+                "severity=\"\(violation.severity.rawValue.lowercaseString)\" " +
+                "message=\"\(violation.reason)\"/>\n" +
+                "\t</file>"
+        }.joinWithSeparator("")
+        report += "\n</checkstyle>"
+        return report
+    }
+}

Source/SwiftLintFrameworkTests/ReporterTests.swift

@@ -65,4 +65,16 @@ class ReporterTests: XCTestCase {
             "filename,1,2,Error,Line Length,Violation Reason.,line_length"
         )
     }
+
+    func testCheckstyleReporter() {
+        XCTAssertEqual(
+            CheckstyleReporter.generateReport(generateViolations()),
+            "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n<checkstyle version=\"4.3\">\n" +
+            "\t<file name=\"filename\">\n\t\t<error line=\"1\" column=\"2\" severity=\"warning\" " +
+            "message=\"Violation Reason.\"/>\n\t</file>\n" +
+            "\t<file name=\"filename\">\n\t\t<error line=\"1\" column=\"2\" severity=\"error\" " +
+            "message=\"Violation Reason.\"/>\n\t</file>\n" +
+            "</checkstyle>"
+        )
+    }
 }

SwiftLint.xcodeproj/project.pbxproj

@@ -88,6 +88,7 @@
 		E8C0DFCD1AD349DB007EE3D4 /* SWXMLHash.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = E8C0DFCC1AD349DB007EE3D4 /* SWXMLHash.framework */; };
 		E8C0DFCE1AD349E5007EE3D4 /* SWXMLHash.framework in Copy Frameworks */ = {isa = PBXBuildFile; fileRef = E8C0DFCC1AD349DB007EE3D4 /* SWXMLHash.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		E8C164C21BEA9EDA00177258 /* ASTRuleTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = E8BB8F991B17DDB200199606 /* ASTRuleTests.swift */; };
+		E8EA41171C2D1DBE004F9930 /* CheckstyleReporter.swift in Sources */ = {isa = PBXBuildFile; fileRef = E8EA41161C2D1DBE004F9930 /* CheckstyleReporter.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -235,6 +236,7 @@
 		E8BB8F991B17DDB200199606 /* ASTRuleTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ASTRuleTests.swift; sourceTree = "<group>"; };
 		E8BB8F9B1B17DE3B00199606 /* StringRuleTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = StringRuleTests.swift; sourceTree = "<group>"; };
 		E8C0DFCC1AD349DB007EE3D4 /* SWXMLHash.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; path = SWXMLHash.framework; sourceTree = BUILT_PRODUCTS_DIR; };
+		E8EA41161C2D1DBE004F9930 /* CheckstyleReporter.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = CheckstyleReporter.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -450,6 +452,7 @@
 		E86396C31BADAC0D002C9E88 /* Reporters */ = {
 			isa = PBXGroup;
 			children = (
+				E8EA41161C2D1DBE004F9930 /* CheckstyleReporter.swift */,
 				E86396CA1BADB519002C9E88 /* CSVReporter.swift */,
 				E86396C81BADB2B9002C9E88 /* JSONReporter.swift */,
 				E86396C41BADAC15002C9E88 /* XcodeReporter.swift */,
@@ -725,6 +728,7 @@
 				E88198531BEA944400333A11 /* LineLengthRule.swift in Sources */,
 				E88198441BEA93D200333A11 /* ColonRule.swift in Sources */,
 				E809EDA11B8A71DF00399043 /* Configuration.swift in Sources */,
+				E8EA41171C2D1DBE004F9930 /* CheckstyleReporter.swift in Sources */,
 				E88DEA731B0984C400A66CB0 /* String+SwiftLint.swift in Sources */,
 				E88198591BEA95F100333A11 /* LeadingWhitespaceRule.swift in Sources */,
 				24E17F721B14BB3F008195BE /* File+Cache.swift in Sources */,