Ensure thread safety on caching images

Author: devxoul

Sources/SwiftyImage.swift

@@ -120,6 +120,7 @@ open class ImageDrawer {
 
   // MARK: Cache
 
+  private static let lock: NSLock = NSLock()
   private static var cachedImages = [String: UIImage]()
   private var cacheKey: String {
     var attributes = [String: String]()
@@ -267,8 +268,10 @@ open class ImageDrawer {
   }
 
   private func imageWithSize(_ size: CGSize, useCache: Bool = true) -> UIImage {
-    if let cachedImage = type(of: self).cachedImages[self.cacheKey], useCache {
-      return cachedImage
+    if useCache {
+      if let cachedImage = type(of: self).cachedImages[self.cacheKey] {
+        return cachedImage
+      }
     }
 
     var imageSize = CGSize(width: size.width, height: size.height)
@@ -448,7 +451,9 @@ open class ImageDrawer {
     }
 
     if useCache {
-      type(of: self).cachedImages[self.cacheKey] = image
+      ImageDrawer.lock.lock()
+      ImageDrawer.cachedImages[self.cacheKey] = image
+      ImageDrawer.lock.unlock()
     }
 
     return image

SwiftyImageTests/SwiftyImageTests.swift

@@ -8,29 +8,17 @@
 
 import UIKit
 import XCTest
+import SwiftyImage
 
 class SwiftyImageTests: XCTestCase {
-    
-    override func setUp() {
-        super.setUp()
-        // Put setup code here. This method is called before the invocation of each test method in the class.
+  func testCacheLock() {
+    for _ in 0..<100 {
+      DispatchQueue.global().async {
+        _ = UIImage.resizable().border(width: 1).corner(radius: 15).image
+      }
     }
-    
-    override func tearDown() {
-        // Put teardown code here. This method is called after the invocation of each test method in the class.
-        super.tearDown()
-    }
-    
-    func testExample() {
-        // This is an example of a functional test case.
-        XCTAssert(true, "Pass")
-    }
-    
-    func testPerformanceExample() {
-        // This is an example of a performance test case.
-        self.measure() {
-            // Put the code you want to measure the time of here.
-        }
-    }
-    
+
+    let expectation = XCTestExpectation()
+    XCTWaiter().wait(for: [expectation], timeout: 1)
+  }
 }