Fixed iOS target SDK version check.

Fixed the iOS target SDK version check for Cocoapods to validate the
target SDK is greater than or equal to the maximum required SDK for
all Cocoapods included in a project.

This also, modifies the iOS resolver to load the pod configuration
when the plugin starts up, if dependency configuration files change
and adds validation to the iOS SDK build setting.

Bug: 134614506
Change-Id: Ia43d62a7e2c073b91040840e3b6bf08f59d60163

Author: Stewart Miles

source/IOSResolver/src/IOSResolver.cs

@@ -538,6 +538,12 @@ protected override bool Read(string filename, Logger logger) {
     // Project level settings for this module.
     private static ProjectSettings settings = new ProjectSettings(PREFERENCE_NAMESPACE);
 
+    /// <summary>
+    /// Polls for changes to TargetSdk.
+    /// </summary>
+    private static PlayServicesResolver.PropertyPoller<string> targetSdkPoller =
+        new PlayServicesResolver.PropertyPoller<string>("iOS Target SDK");
+
     // Search for a file up to a maximum search depth stopping the
     // depth first search each time the specified file is found.
     private static List<string> FindFile(
@@ -676,7 +682,12 @@ exception is TypeInitializationException ||
             !ExecutionEnvironment.InBatchMode) {
             RunOnMainThread.Run(() => { AutoInstallCocoapods(); }, runNow: false);
         }
-
+        // Install / remove target SDK property poller.
+        SetEnablePollTargetSdk(PodfileGenerationEnabled);
+        // Load XML dependencies on the next editor update.
+        if (PodfileGenerationEnabled) {
+            RunOnMainThread.Run(RefreshXmlDependencies, runNow: false);
+        }
 
         // Prompt the user to use workspaces if they aren't at least using project level
         // integration.
@@ -826,7 +837,21 @@ private static bool LegacyCocoapodsInstallEnabled {
     public static bool PodfileGenerationEnabled {
         get { return settings.GetBool(PREFERENCE_PODFILE_GENERATION_ENABLED,
                                          defaultValue: true); }
-        set { settings.SetBool(PREFERENCE_PODFILE_GENERATION_ENABLED, value); }
+        set {
+            settings.SetBool(PREFERENCE_PODFILE_GENERATION_ENABLED, value);
+            SetEnablePollTargetSdk(value);
+        }
+    }
+
+    /// <summary>
+    /// Enable / disable target SDK polling.
+    /// </summary>
+    private static void SetEnablePollTargetSdk(bool enable) {
+        if (enable && EditorUserBuildSettings.activeBuildTarget == BuildTarget.iOS) {
+            RunOnMainThread.OnUpdate += PollTargetSdk;
+        } else {
+            RunOnMainThread.OnUpdate -= PollTargetSdk;
+        }
     }
 
     /// <summary>
@@ -1104,41 +1129,38 @@ private static void AddPodInternal(string podName,
             return;
         }
         pods[podName] = pod;
+        ScheduleCheckTargetSdk();
+    }
 
-        UpdateTargetSdk(pod);
+    /// <summary>
+    /// Determine whether the target SDK has changed.
+    /// </summary>
+    private static void PollTargetSdk() {
+        targetSdkPoller.Poll(() => TargetSdk,
+                             (previousValue, currentValue) => { ScheduleCheckTargetSdk(); });
     }
 
+    // ID of the job which checks that the target SDK is correct for the currently selected set of
+    // Cocoapods.
+    private static int checkTargetSdkJobId = 0;
+
     /// <summary>
-    /// Update the iOS target SDK if it's lower than the minimum SDK
-    /// version specified by the pod.
+    /// Schedule a check to ensure target SDK is configured correctly given the set of selected
+    /// Cocoapods.
     /// </summary>
-    /// <param name="pod">Pod to query for the minimum supported version.
-    /// </param>
-    /// <param name="notifyUser">Whether to write to the log to notify the
-    /// user of a build setting change.</param>
-    /// <returns>true if the SDK version was changed, false
-    /// otherwise.</returns>
-    private static bool UpdateTargetSdk(Pod pod,
-                                        bool notifyUser = true) {
-        int currentVersion = TargetSdkVersion;
-        int minVersion = pod.MinTargetSdkToVersion();
-        if (currentVersion >= minVersion) {
-            return false;
-        }
-        if (notifyUser) {
-            string oldSdk = TargetSdk;
-            TargetSdkVersion = minVersion;
-            Log("iOS Target SDK changed from " + oldSdk + " to " +
-                TargetSdk + " required by the " + pod.name + " pod");
-        }
-        return true;
+    private static void ScheduleCheckTargetSdk() {
+        RunOnMainThread.Cancel(checkTargetSdkJobId);
+        checkTargetSdkJobId = RunOnMainThread.Schedule(() => {
+                UpdateTargetSdk(false);
+            }, 500.0 /* delay in milliseconds before running the check */);
     }
 
     /// <summary>
     /// Update the target SDK if it's required.
     /// </summary>
+    /// <param name="runningBuild">Whether the build is being processed.</param>
     /// <returns>true if the SDK was updated, false otherwise.</returns>
-    public static bool UpdateTargetSdk() {
+    public static bool UpdateTargetSdk(bool runningBuild) {
         var minVersionAndPodNames = TargetSdkNeedsUpdate();
         if (minVersionAndPodNames.Value != null) {
             var minVersionString =
@@ -1157,12 +1179,14 @@ public static bool UpdateTargetSdk() {
                 "Yes", cancel: "No");
             if (update) {
                 TargetSdkVersion = minVersionAndPodNames.Key;
-                string errorString = (
-                    "Target SDK has been updated from " + TargetSdk +
-                    " to " + minVersionString + ".  You must restart the " +
-                    "build for this change to take effect.");
-                EditorUtility.DisplayDialog(
-                    "Target SDK updated.", errorString, "OK");
+                if (runningBuild) {
+                    string errorString = (
+                        "Target SDK has been updated from " + TargetSdk +
+                        " to " + minVersionString + ".  You must restart the " +
+                        "build for this change to take effect.");
+                    EditorUtility.DisplayDialog(
+                        "Target SDK updated.", errorString, "OK");
+                }
                 return true;
             }
         }
@@ -1173,26 +1197,24 @@ public static bool UpdateTargetSdk() {
     /// Determine whether the target SDK needs to be updated based upon pod
     /// dependencies.
     /// </summary>
-    /// <returns>Key value pair of minimum SDK version (key) and
+    /// <returns>Key value pair of maximum of the minimum SDK versions (key) and
     /// a list of pod names that require it (value) if the currently
     /// selected target SDK version does not satisfy pod requirements, the list
     /// (value) is null otherwise.</returns>
     private static KeyValuePair<int, List<string>> TargetSdkNeedsUpdate() {
-        var kvpair = new KeyValuePair<int, List<string>>(0, null);
-        var podListsByVersion = Pod.BucketByMinSdkVersion(pods.Values);
-        if (podListsByVersion.Count == 0) {
-            return kvpair;
-        }
-        KeyValuePair<int, List<string>> minVersionAndPodName = kvpair;
-        foreach (var versionAndPodList in podListsByVersion) {
-            minVersionAndPodName = versionAndPodList;
-            break;
-        }
-        int currentVersion = TargetSdkVersion;
-        if (currentVersion >= minVersionAndPodName.Key) {
-            return kvpair;
+        var emptyVersionAndPodNames = new KeyValuePair<int, List<string>>(0, null);
+        var minVersionAndPodNames = emptyVersionAndPodNames;
+        int maxOfMinRequiredVersions = 0;
+        foreach (var versionAndPodList in Pod.BucketByMinSdkVersion(pods.Values)) {
+            if (versionAndPodList.Key > maxOfMinRequiredVersions) {
+                maxOfMinRequiredVersions = versionAndPodList.Key;
+                minVersionAndPodNames = versionAndPodList;
+            }
         }
-        return minVersionAndPodName;
+        // If the target SDK version exceeds the minimum required version return an empty tuple
+        // otherwise return the minimum required SDK version and the set of pods that need it.
+        return TargetSdkVersion >= maxOfMinRequiredVersions ? emptyVersionAndPodNames :
+            minVersionAndPodNames;
     }
 
     // Get the path of an xcode project relative to the specified directory.
@@ -1527,6 +1549,29 @@ public static void InstallCocoapods(bool interactive, string workingDirectory,
         if (!interactive) complete.WaitOne();
     }
 
+    /// <summary>
+    /// Called by Unity when all assets have been updated. This refreshes the Pods loaded from
+    /// XML files.
+    /// </summary>
+    /// <param name="importedAssets">Imported assets. (unused)</param>
+    /// <param name="deletedAssets">Deleted assets. (unused)</param>
+    /// <param name="movedAssets">Moved assets. (unused)</param>
+    /// <param name="movedFromAssetPaths">Moved from asset paths. (unused)</param>
+    private static void OnPostprocessAllAssets(string[] importedAssets,
+                                               string[] deletedAssets,
+                                               string[] movedAssets,
+                                               string[] movedFromAssetPaths) {
+        if (!CocoapodsIntegrationEnabled) return;
+        bool dependencyFileChanged = false;
+        var changedAssets = new List<string>(importedAssets);
+        changedAssets.AddRange(deletedAssets);
+        foreach (var asset in changedAssets) {
+            dependencyFileChanged = xmlDependencies.IsDependenciesFile(asset);
+            if (dependencyFileChanged) break;
+        }
+        if (dependencyFileChanged) RefreshXmlDependencies();
+    }
+
     /// <summary>
     /// Refresh XML dependencies if the plugin is enabled.
     /// </summary>
@@ -2150,7 +2195,7 @@ private static CommandLine.Result RunPodCommand(
     public static void OnPostProcessInstallPods(BuildTarget buildTarget,
                                                 string pathToBuiltProject) {
         if (!InjectDependencies() || !PodfileGenerationEnabled) return;
-        if (UpdateTargetSdk()) return;
+        if (UpdateTargetSdk(true)) return;
         if (!CocoapodsIntegrationEnabled || !cocoapodsToolsInstallPresent) {
             Log(String.Format(
                 "Cocoapod installation is disabled.\n" +

source/PlayServicesResolver/src/PlayServicesResolver.cs

@@ -285,7 +285,7 @@ public override string ToString() {
         /// Polls a value and signals a callback with the change after the specified delay
         /// time.
         /// </summary>
-        private class PropertyPoller<T> {
+        internal class PropertyPoller<T> {
             /// <summary>
             /// Delegate that is called when a value changes.
             /// </summary>

source/PlayServicesResolver/src/XmlDependencies.cs

@@ -41,22 +41,29 @@ internal class XmlDependencies {
         /// </summary>
         protected string dependencyType = "dependencies";
 
+        /// <summary>
+        /// Determines whether a filename matches an XML dependencies file.
+        /// </summary>
+        /// <param name="filename"></param>
+        /// <returns>true if it is a match, false otherwise.</returns>
+        internal bool IsDependenciesFile(string filename) {
+            foreach (var regex in fileRegularExpressions) {
+                if (regex.Match(filename).Success) {
+                    return true;
+                }
+            }
+            return false;
+        }
+
         /// <summary>
         /// Find all XML declared dependency files.
         /// </summary>
         /// <returns>List of XML dependency filenames in the project.</returns>
         private List<string> FindFiles() {
             return new List<string>(
                 VersionHandlerImpl.SearchAssetDatabase(
-                    "Dependencies t:TextAsset",
-                    (string filename) => {
-                        foreach (var regex in fileRegularExpressions) {
-                            if (regex.Match(filename).Success) {
-                                return true;
-                            }
-                        }
-                        return false;
-                    }, new [] { "Assets", "Packages"}));
+                   "Dependencies t:TextAsset", IsDependenciesFile,
+                   new [] { "Assets", "Packages"}));
         }
 
         /// <summary>