Disable/re-enable rules from within source code comments. Fixes #4.

CHANGELOG.md

@@ -18,6 +18,11 @@
   names to start with an underscore.
   [JP Simard](https://github.com/jpsim)
 
+* Disable and re-enable rules from within source code comments using
+  `// swiftlint:disable:$IDENTIFIER` and `// swiftlint:enable:$IDENTIFIER`.  
+  [JP Simard](https://github.com/jpsim)
+  [#4](https://github.com/realm/SwiftLint/issues/4)
+
 ##### Bug Fixes
 
 * None.

Source/SwiftLintFramework/File+SwiftLint.swift

@@ -9,9 +9,51 @@
 import SourceKittenFramework
 import SwiftXPC
 
-typealias Line = (index: Int, content: String)
+public typealias Line = (index: Int, content: String)
+
+public typealias Region = (startLine: Int, endLine: Int, disabledRules: [String])
+
+public enum CommandAction: String {
+    case Enable = "enable"
+    case Disable = "disable"
+}
+
+public typealias Command = (CommandAction, String, Int)
 
 extension File {
+    public func regions() -> [Region] {
+        let nsStringContents = contents as NSString
+        let commands = matchPattern("swiftlint:(enable|disable):force_cast")
+            .flatMap { range, syntaxKinds -> Command? in
+                let scanner = NSScanner(string: nsStringContents.substringWithRange(range))
+                scanner.scanString("swiftlint:", intoString: nil)
+                var actionString: NSString? = nil
+                scanner.scanUpToString(":", intoString: &actionString)
+                let start = range.location
+                if let actionString = actionString as String?,
+                    action = CommandAction(rawValue: actionString),
+                    lineRange = nsStringContents.lineRangeWithByteRange(start: start, length: 0) {
+                        scanner.scanString(":", intoString: nil)
+                        let ruleStart = scanner.string.startIndex.advancedBy(scanner.scanLocation)
+                        let rule = scanner.string.substringFromIndex(ruleStart)
+                        return (action, rule, lineRange.start)
+                }
+                return nil
+        }
+        let totalNumberOfLines = contents.lines().count
+        var regions: [Region] = [(1, commands.first?.2 ?? totalNumberOfLines, [])]
+        var disabledRules = Set<String>()
+        let commandPairs = zip(commands, Array(commands.dropFirst().map({Optional($0)})) + [nil])
+        for (command, nextCommand) in commandPairs {
+            switch command.0 {
+            case .Disable: disabledRules.insert(command.1)
+            case .Enable: disabledRules.remove(command.1)
+            }
+            regions.append((command.2, nextCommand?.2 ?? totalNumberOfLines, Array(disabledRules)))
+        }
+        return regions
+    }
+
     public func matchPattern(pattern: String,
         withSyntaxKinds syntaxKinds: [SyntaxKind]) -> [NSRange] {
         return matchPattern(pattern).filter { _, kindsInRange in

Source/SwiftLintFramework/Linter.swift

@@ -16,7 +16,20 @@ public struct Linter {
     private let rules: [Rule]
 
     public var styleViolations: [StyleViolation] {
-        return rules.flatMap { $0.validateFile(self.file) }
+        let regions = file.regions()
+        return rules.flatMap { rule in
+            return rule.validateFile(self.file).filter { styleViolation in
+                guard let line = styleViolation.location.line else {
+                    return true
+                }
+                guard let violationRegion = regions.filter({
+                    $0.startLine < line && $0.endLine > line
+                }).first else {
+                    return true
+                }
+                return !violationRegion.disabledRules.contains(rule.identifier)
+            }
+        }
     }
 
     public var ruleExamples: [RuleExample] {