Add caching of Structure and SyntaxMap.

CHANGELOG.md

@@ -24,6 +24,9 @@
   with examples.  
   [Chris Eidhof](https://github.com/chriseidhof)
 
+* Cache parsing to reduce execution time by more than 50%.
+  [Nikolaj Schumacher](https://github.com/nschum)
+
 ##### Bug Fixes
 
 None.

Source/SwiftLintFramework/File+Cache.swift

@@ -0,0 +1,48 @@
+import SourceKittenFramework
+
+private var structureCache = Cache({file in Structure(file: file)})
+private var syntaxMapCache = Cache({file in SyntaxMap(file: file)})
+
+private struct Cache<T> {
+
+    private var values = [String: T]()
+    private var factory: File -> T
+
+    private init(_ factory: File -> T) {
+        self.factory = factory
+    }
+
+    private mutating func get(file: File) -> T {
+        if let path = file.path {
+            if let value = values[path] {
+                return value
+            } else {
+                let value = factory(file)
+                values[path] = value
+                return value
+            }
+        } else {
+            return factory(file)
+        }
+    }
+
+    private mutating func clear() {
+        values.removeAll(keepCapacity: false)
+    }
+}
+
+public extension File {
+
+    public var structure: Structure {
+        return structureCache.get(self)
+    }
+
+    public var syntaxMap: SyntaxMap {
+        return syntaxMapCache.get(self)
+    }
+
+    public static func clearCaches() {
+        structureCache.clear()
+        syntaxMapCache.clear()
+    }
+}

Source/SwiftLintFramework/File+SwiftLint.swift

@@ -16,7 +16,7 @@ extension File {
         [NSRange] {
         return flatMap(NSRegularExpression(pattern: pattern, options: nil, error: nil)) { regex in
             let range = NSRange(location: 0, length: count(self.contents.utf16))
-            let syntax = SyntaxMap(file: self)
+            let syntax = self.syntaxMap
             let matches = regex.matchesInString(self.contents, options: nil, range: range)
             return map(matches as? [NSTextCheckingResult]) { matches in
                 return compact(matches.map { match in

Source/SwiftLintFramework/Rules/FunctionBodyLengthRule.swift

@@ -23,7 +23,7 @@ public struct FunctionBodyLengthRule: ASTRule, ParameterizedRule {
     ]
 
     public func validateFile(file: File) -> [StyleViolation] {
-        return validateFile(file, dictionary: Structure(file: file).dictionary)
+        return validateFile(file, dictionary: file.structure.dictionary)
     }
 
     public func validateFile(file: File, dictionary: XPCDictionary) -> [StyleViolation] {

Source/SwiftLintFramework/Rules/NestingRule.swift

@@ -15,7 +15,7 @@ public struct NestingRule: ASTRule {
     public let identifier = "nesting"
 
     public func validateFile(file: File) -> [StyleViolation] {
-        return validateFile(file, dictionary: Structure(file: file).dictionary)
+        return validateFile(file, dictionary: file.structure.dictionary)
     }
 
     public func validateFile(file: File, dictionary: XPCDictionary) -> [StyleViolation] {

Source/SwiftLintFramework/Rules/TypeBodyLengthRule.swift

@@ -23,7 +23,7 @@ public struct TypeBodyLengthRule: ASTRule, ParameterizedRule {
     ]
 
     public func validateFile(file: File) -> [StyleViolation] {
-        return validateFile(file, dictionary: Structure(file: file).dictionary)
+        return validateFile(file, dictionary: file.structure.dictionary)
     }
 
     public func validateFile(file: File, dictionary: XPCDictionary) -> [StyleViolation] {

Source/SwiftLintFramework/Rules/TypeNameRule.swift

@@ -15,7 +15,7 @@ public struct TypeNameRule: ASTRule {
     public let identifier = "type_name"
 
     public func validateFile(file: File) -> [StyleViolation] {
-        return validateFile(file, dictionary: Structure(file: file).dictionary)
+        return validateFile(file, dictionary: file.structure.dictionary)
     }
 
     public func validateFile(file: File, dictionary: XPCDictionary) -> [StyleViolation] {

Source/SwiftLintFramework/Rules/VariableNameRule.swift

@@ -15,7 +15,7 @@ public struct VariableNameRule: ASTRule {
     public let identifier = "variable_name"
 
     public func validateFile(file: File) -> [StyleViolation] {
-        return validateFile(file, dictionary: Structure(file: file).dictionary)
+        return validateFile(file, dictionary: file.structure.dictionary)
     }
 
     public func validateFile(file: File, dictionary: XPCDictionary) -> [StyleViolation] {

SwiftLint.xcodeproj/project.pbxproj

@@ -7,6 +7,7 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		24E17F721B14BB3F008195BE /* File+Cache.swift in Sources */ = {isa = PBXBuildFile; fileRef = 24E17F701B1481FF008195BE /* File+Cache.swift */; };
 		83894F221B0C928A006214E1 /* RulesCommand.swift in Sources */ = {isa = PBXBuildFile; fileRef = 83894F211B0C928A006214E1 /* RulesCommand.swift */; };
 		83D71E281B131ECE000395DE /* RuleExample.swift in Sources */ = {isa = PBXBuildFile; fileRef = 83D71E261B131EB5000395DE /* RuleExample.swift */; };
 		83D71E2B1B131EED000395DE /* AnsiCode.swift in Sources */ = {isa = PBXBuildFile; fileRef = 83D71E231B131C11000395DE /* AnsiCode.swift */; };
@@ -102,6 +103,7 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
+		24E17F701B1481FF008195BE /* File+Cache.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "File+Cache.swift"; sourceTree = "<group>"; };
 		5499CA961A2394B700783309 /* Components.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Components.plist; sourceTree = "<group>"; };
 		5499CA971A2394B700783309 /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		83894F211B0C928A006214E1 /* RulesCommand.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = RulesCommand.swift; sourceTree = "<group>"; };
@@ -328,6 +330,7 @@
 			children = (
 				E88DEA8B1B0999A000A66CB0 /* ASTRule.swift */,
 				E88DEA741B09852000A66CB0 /* File+SwiftLint.swift */,
+				24E17F701B1481FF008195BE /* File+Cache.swift */,
 				E812249B1B04FADC001783D2 /* Linter.swift */,
 				E88DEA6E1B09843F00A66CB0 /* Location.swift */,
 				E88DEA761B098D0C00A66CB0 /* Rule.swift */,
@@ -565,6 +568,7 @@
 				E88DEA841B0990F500A66CB0 /* ColonRule.swift in Sources */,
 				E88DEA791B098D4400A66CB0 /* RuleParameter.swift in Sources */,
 				E88DEA731B0984C400A66CB0 /* String+SwiftLint.swift in Sources */,
+				24E17F721B14BB3F008195BE /* File+Cache.swift in Sources */,
 				E88DEA6D1B09842200A66CB0 /* StyleViolationType.swift in Sources */,
 				E88DEA941B099C0900A66CB0 /* VariableNameRule.swift in Sources */,
 				E88DEA8A1B0992B300A66CB0 /* FileLengthRule.swift in Sources */,