Improved logging

Author: lukaskubanek

Sources/InterposeKit/Hooks/Hook.swift

@@ -177,24 +177,27 @@ public final class Hook {
     // ============================================================================ //
 
     deinit {
-        var logComponents = [String]()
-        
-        switch self.state {
-        case .pending:
-            logComponents.append("Releasing")
-        case .active:
-            logComponents.append("Keeping")
-        case .failed:
-            logComponents.append("Leaking")
-        }
-        
-        logComponents.append("-[\(self.class) \(self.selector)]")
-        
-        if let hookIMP = self.strategy.appliedHookIMP {
-            logComponents.append("IMP: \(hookIMP)")
-        }
-        
-        Interpose.log(logComponents.joined(separator: " "))
+        Interpose.log({
+            var components = [String]()
+            
+            switch self.state {
+            case .pending:
+                components.append("Releasing")
+            case .active:
+                components.append("Keeping")
+            case .failed:
+                components.append("Leaking")
+            }
+            
+            components.append("hook for")
+            components.append("-[\(self.class) \(self.selector)]")
+            
+            if let hookIMP = self.strategy.appliedHookIMP {
+                components.append("IMP: \(hookIMP)")
+            }
+            
+            return components.joined(separator: " ")
+        }())
     }
 
 }

Sources/InterposeKit/Hooks/HookStrategy/ClassHookStrategy/ClassHookStrategy.swift

@@ -81,7 +81,7 @@ internal final class ClassHookStrategy: HookStrategy {
         self.appliedHookIMP = hookIMP
         self.storedOriginalIMP = originalIMP
 
-        Interpose.log("Swizzled -[\(self.class) \(self.selector)] IMP: \(originalIMP) -> \(hookIMP)")
+        Interpose.log("Replaced implementation for -[\(self.class) \(self.selector)] IMP: \(originalIMP) -> \(hookIMP)")
     }
 
     internal func restoreImplementation() throws {
@@ -116,7 +116,7 @@ internal final class ClassHookStrategy: HookStrategy {
             )
         }
 
-        Interpose.log("Restored -[\(self.class) \(self.selector)] IMP: \(originalIMP)")
+        Interpose.log("Restored implementation for -[\(self.class) \(self.selector)] IMP: \(originalIMP)")
     }
 
 }

Sources/InterposeKit/Hooks/HookStrategy/ObjectHookStrategy/ObjectHookStrategy.swift

@@ -74,7 +74,7 @@ final class ObjectHookStrategy: HookStrategy {
             do {
                 try ITKSuperBuilder.addSuperInstanceMethod(to: dynamicSubclass, selector: self.selector)
                 let imp = class_getMethodImplementation(dynamicSubclass, self.selector)!
-                Interpose.log("Added super trampoline for -[\(dynamicSubclass) \(self.selector)]: \(imp)")
+                Interpose.log("Added super trampoline for -[\(dynamicSubclass) \(self.selector)] IMP: \(imp)")
             } catch {
                 // Interpose.log("Failed to add super implementation to -[\(dynamicClass).\(selector)]: \(error)")
                 throw InterposeError.unknownError(String(describing: error))
@@ -92,7 +92,7 @@ final class ObjectHookStrategy: HookStrategy {
                 selector: self.selector
             )
         }
-        Interpose.log("Added -[\(self.class).\(self.selector)] IMP: \(self.storedOriginalIMP!) -> \(hookIMP)")
+        Interpose.log("Replaced implementation for -[\(self.class) \(self.selector)] IMP: \(self.storedOriginalIMP!) -> \(hookIMP)")
     }
 
     func restoreImplementation() throws {
@@ -127,7 +127,7 @@ final class ObjectHookStrategy: HookStrategy {
                     imp: previousIMP
                 )
             }
-            Interpose.log("Restored -[\(self.class).\(self.selector)] IMP: \(originalIMP)")
+            Interpose.log("Restored implementation for -[\(self.class) \(self.selector)] IMP: \(originalIMP)")
         } else {
             let nextHook = self._findParentHook(from: currentIMP)
             // Replace next's original IMP

Sources/InterposeKit/Hooks/HookStrategy/ObjectHookStrategy/ObjectSubclassManager.swift

@@ -23,6 +23,12 @@ internal enum ObjectSubclassManager {
     ) throws -> AnyClass {
         // If there is a dynamic subclass already installed on the object, reuse it straightaway.
         if let installedSubclass = self.installedSubclass(for: object) {
+            Interpose.log({
+                let subclassName = NSStringFromClass(installedSubclass)
+                let objectAddress = String(format: "%p", object)
+                return "Reused subclass: \(subclassName) for object \(objectAddress)"
+            }())
+            
             return installedSubclass
         }
 
@@ -33,8 +39,18 @@ internal enum ObjectSubclassManager {
         // Then, set the created class on the object.
         object_setClass(object, subclass)
 
-        let oldName = NSStringFromClass(class_getSuperclass(object_getClass(object))!)
-        Interpose.log("Generated \(NSStringFromClass(subclass)) for object (was: \(oldName))")
+        Interpose.log({
+            let subclassName = NSStringFromClass(subclass)
+            let objectAddress = String(format: "%p", object)
+            var message = "Created subclass: \(subclassName) for object \(objectAddress)"
+            
+            if let superclass = class_getSuperclass(subclass) {
+                let superclassName = NSStringFromClass(superclass)
+                message += " (was: \(superclassName))"
+            }
+            
+            return message
+        }())
 
         return subclass
     }

Sources/InterposeKit/Interpose.swift

@@ -88,14 +88,18 @@ public enum Interpose {
     /// The flag indicating whether logging is enabled.
     public static var isLoggingEnabled = false
 
-    internal static func log(_ message: String) {
+    internal static func log(
+        _ message: @autoclosure () -> String
+    ) {
         if self.isLoggingEnabled {
-            print("[InterposeKit] \(message)")
+            print("[InterposeKit] \(message())")
         }
     }
 
-    internal static func fail(_ message: String) -> Never {
-        fatalError("[InterposeKit] \(message)")
+    internal static func fail(
+        _ message: @autoclosure () -> String
+    ) -> Never {
+        fatalError("[InterposeKit] \(message())")
     }
 
 }