Reduced build time avoiding building same framework several times

build.cake

@@ -1,4 +1,4 @@
-#addin nuget:?package=Cake.XCode&version=4.1.0
+#addin nuget:?package=Cake.XCode&version=4.2.0
 #addin nuget:?package=Cake.Xamarin.Build&version=4.1.1
 #addin nuget:?package=Cake.FileHelpers&version=3.2.0
 

common.cake

@@ -77,6 +77,8 @@ void BuildSdkOnPodfile (Artifact artifact)
 	var podsProject = "./Pods/Pods.xcodeproj";
 	var workingDirectory = (DirectoryPath)$"./externals/{artifact.Id}";
 
+	var podSpecsToBuild = new List<PodSpec> ();
+
 	foreach (var podSpec in artifact.PodSpecs)
 	{
 		if (podSpec.FrameworkSource != FrameworkSource.Pods)
@@ -89,13 +91,21 @@ void BuildSdkOnPodfile (Artifact artifact)
 			if (!podSpec.CanBeBuild)
 				continue;
 
-			BuildXcodeFatFramework (podsProject, podSpec.TargetName, platforms, libraryTitle: podSpec.FrameworkName, workingDirectory: workingDirectory);
-			CopyDirectory ($"{workingDirectory}/{framework}", $"./externals/{framework}");
+			podSpecsToBuild.Add (podSpec);
+			// BuildXcodeFatFramework (podsProject, podSpec.TargetName, platforms, libraryTitle: podSpec.FrameworkName, workingDirectory: workingDirectory);
+			// CopyDirectory ($"{workingDirectory}/{framework}", $"./externals/{framework}");
 		} else {
 			foreach (var path in paths)
 				CopyDirectory (path, $"./externals/{framework}");
 		}
 	}
+
+	BuildXcodeFatFramework (podsProject, podSpecsToBuild.ToArray (), platforms, workingDirectory: workingDirectory);
+
+	foreach (var podSpec in podSpecsToBuild) {
+		var framework = $"{podSpec.FrameworkName}.framework";
+		CopyDirectory ($"{workingDirectory}/{framework}", $"./externals/{framework}");
+	}
 }
 
 void CleanVisualStudioSolution ()
@@ -216,6 +226,76 @@ void BuildXcodeFatFramework (FilePath xcodeProject, string target, Platform [] p
 		DeleteFile (fatFrameworkPath.CombineWithFilePath (target));
 }
 
+void BuildXcodeFatFramework (FilePath xcodeProject, PodSpec [] podSpecs, Platform [] platforms, DirectoryPath workingDirectory = null, Dictionary<string, string> buildSettings = null)
+{
+	if (!IsRunningOnUnix ()) {
+		Warning("{0} is not available on the current platform.", "xcodebuild");
+		return;
+	}
+	
+	workingDirectory = workingDirectory ?? Directory("./externals/");
+
+	foreach (var podSpec in podSpecs) {
+		var target = podSpec.TargetName;
+		var libraryTitle = podSpec.FrameworkName;
+		var fatFramework = (DirectoryPath)$"{libraryTitle}.framework";
+		
+		foreach (var platform in platforms) {
+			var sdk = platform.Sdk;
+			var arch = platform.Arch;
+
+			var platformFramework = (DirectoryPath)$"{libraryTitle}-{arch}.framework";
+			var platformFrameworkPath = workingDirectory.Combine (platformFramework);
+
+			if (DirectoryExists (platformFrameworkPath))
+				continue;
+
+			var buildPath = buildSettings != null && buildSettings.ContainsKey ("SYMROOT") ? 
+				Directory (buildSettings ["SYMROOT"]) : workingDirectory.Combine ("build");
+
+			XCodeBuild (new XCodeBuildSettings {
+				Project = workingDirectory.CombineWithFilePath (xcodeProject).ToString (),
+				Target = target,
+				Sdk = sdk,
+				Arch = arch,
+				Configuration = "Release",
+				Verbose = true,
+				BuildSettings = buildSettings
+			});
+
+			var releasePath = buildPath.Combine ($"Release-{sdk}");
+
+			foreach (var p in podSpecs) {
+				var outputPath = releasePath.Combine (p.TargetName);
+				var lt = p.FrameworkName;
+				var ff = (DirectoryPath)$"{lt}.framework";
+				var frameworkOutputPath = outputPath.Combine (ff);
+
+				if (!DirectoryExists (frameworkOutputPath))
+					continue;
+				
+				var fatFrameworkPath = workingDirectory.Combine (ff);
+
+				if (!DirectoryExists (fatFrameworkPath))
+					CopyDirectory (frameworkOutputPath, fatFrameworkPath);
+
+				var pf = (DirectoryPath)$"{lt}-{arch}.framework";
+				var pfp = workingDirectory.Combine (pf);
+
+				CopyDirectory (frameworkOutputPath, pfp);
+			}
+		}
+
+		var archPaths = new List<FilePath> ();
+		var paths = GetFiles ($"{workingDirectory}/{libraryTitle}-*/{libraryTitle}");
+
+		foreach (var path in paths)
+			archPaths.Add (path);
+
+		RunLipoCreate (workingDirectory, fatFramework.CombineWithFilePath (libraryTitle), archPaths.ToArray ());
+	}
+}
+
 bool TargetExistsInXcodeProject (FilePath xcodeProject, string target, DirectoryPath workingDirectory = null)
 {
 	workingDirectory = workingDirectory ?? Directory("./externals/");