Merge pull request #16 from zenangst/feature/customizable-diffing

Refactor implementation to offer more customization
zenangst · Mar 3, 2019 · 903f828 · 903f828
2 parents baca25f + 78ce95a
commit 903f828
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Showing 6 changed files with 102 additions and 8 deletions.
diff --git a/Differific.xcodeproj/project.pbxproj b/Differific.xcodeproj/project.pbxproj
@@ -46,6 +46,9 @@
 		BDBF80E8209252440002CE93 /* UICollectionViewExtensionsTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = BDBF80E5209252440002CE93 /* UICollectionViewExtensionsTests.swift */; };
 		BDBF80EA20927B080002CE93 /* NSCollectionViewExtensionTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = BDBF80E920927B080002CE93 /* NSCollectionViewExtensionTests.swift */; };
 		BDBF80EC20927B360002CE93 /* NSTableViewExtensionsTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = BDBF80EB20927B360002CE93 /* NSTableViewExtensionsTests.swift */; };
+		BDED0DC8222C57A800D7B46E /* Diffable.swift in Sources */ = {isa = PBXBuildFile; fileRef = BDED0DC7222C57A800D7B46E /* Diffable.swift */; };
+		BDED0DC9222C57A800D7B46E /* Diffable.swift in Sources */ = {isa = PBXBuildFile; fileRef = BDED0DC7222C57A800D7B46E /* Diffable.swift */; };
+		BDED0DCA222C57A800D7B46E /* Diffable.swift in Sources */ = {isa = PBXBuildFile; fileRef = BDED0DC7222C57A800D7B46E /* Diffable.swift */; };
 		D284B1051F79038B00D94AF3 /* Differific.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = D284B0FC1F79038B00D94AF3 /* Differific.framework */; };
 		D284B1381F7906DB00D94AF3 /* Info-iOS-Tests.plist in Resources */ = {isa = PBXBuildFile; fileRef = D284B12F1F7906DA00D94AF3 /* Info-iOS-Tests.plist */; };
 		D284B1391F7906DB00D94AF3 /* Info-tvOS-Tests.plist in Resources */ = {isa = PBXBuildFile; fileRef = D284B1301F7906DA00D94AF3 /* Info-tvOS-Tests.plist */; };
@@ -99,6 +102,7 @@
 		BDBF80E5209252440002CE93 /* UICollectionViewExtensionsTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UICollectionViewExtensionsTests.swift; sourceTree = "<group>"; };
 		BDBF80E920927B080002CE93 /* NSCollectionViewExtensionTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NSCollectionViewExtensionTests.swift; sourceTree = "<group>"; };
 		BDBF80EB20927B360002CE93 /* NSTableViewExtensionsTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NSTableViewExtensionsTests.swift; sourceTree = "<group>"; };
+		BDED0DC7222C57A800D7B46E /* Diffable.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Diffable.swift; sourceTree = "<group>"; };
 		D284B0FC1F79038B00D94AF3 /* Differific.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Differific.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		D284B1041F79038B00D94AF3 /* Differific-tvOS-Tests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = "Differific-tvOS-Tests.xctest"; sourceTree = BUILT_PRODUCTS_DIR; };
 		D284B1181F79039F00D94AF3 /* Differific.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Differific.framework; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -283,6 +287,7 @@
 				BD690D4F20DC143100E56E30 /* ArrayEntry.swift */,
 				BDBF80C420923FD00002CE93 /* Change.swift */,
 				BD690D4720DC13F700E56E30 /* Counter.swift */,
+				BDED0DC7222C57A800D7B46E /* Diffable.swift */,
 				BDBF80C320923FD00002CE93 /* DiffManager.swift */,
 				BDBF80C520923FD00002CE93 /* IndexPathManager.swift */,
 				BD690D4B20DC141200E56E30 /* TableEntry.swift */,
@@ -587,6 +592,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				BDED0DCA222C57A800D7B46E /* Diffable.swift in Sources */,
 				BDBF80CF20923FD00002CE93 /* IndexPathManager.swift in Sources */,
 				BDBF80D220923FD00002CE93 /* Algorithm.swift in Sources */,
 				BDBF80BC20923FB90002CE93 /* UICollectionView+Extensions.swift in Sources */,
@@ -621,6 +627,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				BDED0DC8222C57A800D7B46E /* Diffable.swift in Sources */,
 				BDBF80CD20923FD00002CE93 /* IndexPathManager.swift in Sources */,
 				BDBF80D020923FD00002CE93 /* Algorithm.swift in Sources */,
 				BDBF80BB20923FB90002CE93 /* UICollectionView+Extensions.swift in Sources */,
@@ -648,6 +655,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				BDED0DC9222C57A800D7B46E /* Diffable.swift in Sources */,
 				BDBF80CE20923FD00002CE93 /* IndexPathManager.swift in Sources */,
 				BDBF80D120923FD00002CE93 /* Algorithm.swift in Sources */,
 				BDBF80D820923FFA0002CE93 /* NSTableView+Extensions.swift in Sources */,

diff --git a/Source/Shared/Algorithm.swift b/Source/Shared/Algorithm.swift
@@ -1,7 +1,7 @@
 import Foundation
 
 class Algorithm {
-  public static func diff<T: Hashable>(old: [T], new: [T]) -> [Change<T>] {
+  public static func diff<T: Hashable>(old: [T], new: [T], compare: (T,T) -> Bool) -> [Change<T>] {
     if new.isEmpty {
       var changes = [Change<T>]()
       changes.reserveCapacity(old.count)
@@ -35,28 +35,30 @@ class Algorithm {
 
     // 1 Pass
     for element in new[0...].lazy {
+      let diffValue = (element as? Diffable)?.diffValue ?? element.hashValue
       let entry: TableEntry
-      if let tableEntry = table[element.hashValue] {
+      if let tableEntry = table[diffValue] {
         entry = tableEntry
       } else {
         entry = TableEntry()
       }
 
-      table[element.hashValue] = entry
+      table[diffValue] = entry
       entry.newCounter += 1
       newArray.append(ArrayEntry(tableEntry: entry))
     }
 
     // 2 Pass
     for element in old[0...].lazy {
+      let diffValue = (element as? Diffable)?.diffValue ?? element.hashValue
       let entry: TableEntry
-      if let tableEntry = table[element.hashValue] {
+      if let tableEntry = table[diffValue] {
         entry = tableEntry
       } else {
         entry = TableEntry()
       }
 
-      table[element.hashValue] = entry
+      table[diffValue] = entry
       entry.oldCounter += 1
       entry.indexesInOld.append(offset)
       oldArray.append(ArrayEntry(tableEntry: entry))
@@ -135,7 +137,7 @@ class Algorithm {
         runningOffset += 1
       } else {
         let oldIndex = element.indexInOther
-        if old[oldIndex] != new[offset] {
+        if !compare(old[oldIndex], new[offset]) {
           changes.append(Change(.update,
                                 item: old[oldIndex],
                                 index: oldIndex,

diff --git a/Source/Shared/DiffManager.swift b/Source/Shared/DiffManager.swift
@@ -2,7 +2,8 @@ import Foundation
 
 public class DiffManager {
   public init() {}
-  public func diff<T: Hashable>(_ old: [T], _ new: [T]) -> [Change<T>] {
-    return Algorithm.diff(old: old, new: new)
+  public func diff<T: Hashable>(_ old: [T], _ new: [T],
+                                compare: (T,T) -> Bool = { $0 == $1 }) -> [Change<T>] {
+    return Algorithm.diff(old: old, new: new, compare: compare)
   }
 }
diff --git a/Source/Shared/Diffable.swift b/Source/Shared/Diffable.swift
@@ -0,0 +1,5 @@
+import Foundation
+
+public protocol Diffable {
+  var diffValue: Int { get }
+}
diff --git a/Tests/Shared/DiffManagerTests.swift b/Tests/Shared/DiffManagerTests.swift
@@ -2,6 +2,13 @@ import XCTest
 import Differific
 
 class DiffManagerTests: XCTestCase {
+  struct MockDiffable: Hashable, Diffable {
+    let id: Int
+    var diffValue: Int {
+      return id
+    }
+  }
+
   struct MockObject: Hashable {
     let id: Int
     let name: String
@@ -148,6 +155,47 @@ class DiffManagerTests: XCTestCase {
     XCTAssertEqual(result.count, 5)
   }
 
+  func testComparator() {
+    let old = [
+      MockObject(id: 0, name: "Foo"),
+      MockObject(id: 1, name: "Bar"),
+      MockObject(id: 2, name: "Baz")
+    ]
+    let new = [
+      MockObject(id: 1, name: "Foo0"),
+      MockObject(id: 0, name: "Bar1"),
+      MockObject(id: 3, name: "Baz2")
+    ]
+
+    let diffManager = DiffManager()
+    let changes = diffManager.diff(old, new, compare: { $0.id == $1.id })
+
+    XCTAssertEqual(changes[0].kind, .delete)
+    XCTAssertEqual(changes[1].kind, .move)
+    XCTAssertEqual(changes[2].kind, .insert)
+  }
+
+  func testDiffable() {
+    let old = [
+      MockDiffable(id: 0),
+      MockDiffable(id: 1),
+      MockDiffable(id: 2)
+    ]
+
+    let new = [
+      MockDiffable(id: 1),
+      MockDiffable(id: 0),
+      MockDiffable(id: 3)
+    ]
+
+    let diffManager = DiffManager()
+    let changes = diffManager.diff(old, new)
+
+    XCTAssertEqual(changes[0].kind, .delete)
+    XCTAssertEqual(changes[1].kind, .move)
+    XCTAssertEqual(changes[2].kind, .insert)
+  }
+
   func testPerformance() {
     let diffManager = DiffManager()
     var old = [Int]()

diff --git a/codecov.yml b/codecov.yml
@@ -0,0 +1,30 @@
+ignore:
+  - "Applications/Xcode.app/.*"
+  - "bin"
+  - "Example"
+  - "Tests"
+  - "Images"
+  - "Info"
+coverage:
+  status:
+    project:
+      default: off
+      macOS:
+        flags: macOS
+      tvOS:
+        flags: tvOS
+      iOS:
+        flags: iOS
+flags:
+  macOS:
+    paths:
+      - Source/macOS
+      - Source/Shared
+  tvOS:
+    paths:
+      - Source/iOS+tvOS
+      - Source/Shared
+  iOS:
+    paths:
+      - Source/iOS+tvOS
+      - Source/Shared