Factored +calculateUpgradeState out of -init. Magic stuff in -init leads to confusion. Also, now this method can be invoked during mid-app run if desired. I use this now in BookMacster to “Reset and Start Over” to a “New User” state.

Author: jerrykrinock

SSYAppInfo.h

@@ -1,6 +1,7 @@
 #import <Cocoa/Cocoa.h>
 #import "SSYVersionTriplet.h"
 
+extern NSString* const constKeyLastVersion ;
 
 /*!
  @enum       SSYAppInfoUpgradeState
@@ -35,18 +36,7 @@ enum SSYAppInfoUpgradeState  {
  previous launch.  I'm not sure where I'm going with this class right now.  Might
  add other "features" later.
 
- @details  Upon initialization, if found to be running a version that is different
- than the previous version in standard user defaults' constKeyLastVersion, an
- instance of this class (the shared instance, for instance) will overwrite the
- constKeyLastVersion user default with the current version.  This should be done
- early in the application launch to make sure that this information gets updated.
- It should be done at least once during an application launch in order to register
- constKeyLastVersion to provide accurate info during the ^next^ launch of this
- application.
- That being said, this is now a reason for using an instance with instance variables. The
- ivars _previousVersionNumbers and consequently _upgradeState can no longer be computed
- from data stored on disk (in user defaults) after this overwriting has been done.
- 
+ @details
  Regarding version strings, this class uses what I call "SSYSimpleVersioningSystem" instead
  of Apple Generic Versioning.  In SSYSimpleVersioningSystem, CFBundleVersion contains two-dot
  string of three integers, major.minor.bugfix.  So, for example in the About box your
@@ -86,5 +76,24 @@ enum SSYAppInfoUpgradeState  {
 
 + (SSYVersionTriplet*)previousVersionTriplet ;
 
+/*
+ @brief    Sets the current upgrade state in the receiver's shared instance,
+ and updates the constKeyLastVersion in the user defaults to the current
+ version found in the app's main bundle.
+ 
+ @details  This method must be invoked before you invoke any other methods
+ in this class, such as early in -applicaitonDidFinishLaunching, or else
+ other methods will give wrong answers.
+ 
+ The current upgrade state is calculated by comparing the
+ last-run version found in standard user defaults' constKeyLastVersion
+ with the current version found in the main bundle, and remembers it.
+ 
+ The reason for setting the current upgrade state (it's an instance variable)
+ is that, after the user defaults' constKeyLastVersion has been updated to the
+ current version, it can no longer be calculated.
+ */
++ (void)calculateUpgradeState ;
+
 @end
 

SSYAppInfo.m

@@ -10,7 +10,8 @@ @implementation SSYAppInfo
 + (SSYAppInfo*)sharedInfo {
 	@synchronized(self) {
         if (sharedInfo == nil) {
-            sharedInfo = [[self alloc] init] ; 
+            sharedInfo = [[self alloc] init] ;
+            [sharedInfo setUpgradeState:SSYNotDefined] ;
         }
 	}
     return sharedInfo ;
@@ -76,31 +77,26 @@ + (SSYVersionTriplet*)rawCurrentVersionTriplet {
 	return cvt ;
 }
 
-
-- (id)init {
-	self = [super init] ;
-	if (self != nil) {
-		SSYVersionTriplet* previousVersionTriplet = [SSYAppInfo rawPreviousVersionTriplet] ;
-		[self setPreviousVersionTriplet:previousVersionTriplet] ;
-		[self setCurrentVersionTriplet:[SSYAppInfo rawCurrentVersionTriplet]] ;
-        enum SSYAppInfoUpgradeState upgradeState = [SSYAppInfo upgradeStateForCurrentVersionTriplet:[self currentVersionTriplet]
-                                                                             previousVersionTriplet:[self previousVersionTriplet]] ;
-		[self setUpgradeState:upgradeState] ;
-		if ([self upgradeState] != SSYCurrentRev) {
-			// Get a nice, clean, filtered versionString of the form "major.minor.bugFix" using SSVersionTriplet methods
-			SSYVersionTriplet* currentVersionTriplet = [SSYVersionTriplet versionTripletFromBundleIdentifier:[[NSBundle mainBundle] bundleIdentifier]] ;
-			NSString* currentVersionString = [currentVersionTriplet string] ;
-
-			// Record currently-launched version into prefs
-			// Note that this must be done AFTER the above reading,
-			// or else the pref constKeyLastVersion will be written as the previous version!
-			NSUserDefaults* userDefaults = [NSUserDefaults standardUserDefaults] ;
-			[userDefaults setObject:currentVersionString
-							 forKey:constKeyLastVersion] ;
-			[userDefaults synchronize] ;
-		}
-	}
-	return self;
+- (void)calculateUpgradeState {
+    SSYVersionTriplet* previousVersionTriplet = [SSYAppInfo rawPreviousVersionTriplet] ;
+    [self setPreviousVersionTriplet:previousVersionTriplet] ;
+    [self setCurrentVersionTriplet:[SSYAppInfo rawCurrentVersionTriplet]] ;
+    enum SSYAppInfoUpgradeState upgradeState = [SSYAppInfo upgradeStateForCurrentVersionTriplet:[self currentVersionTriplet]
+                                                                         previousVersionTriplet:[self previousVersionTriplet]] ;
+    [self setUpgradeState:upgradeState] ;
+    if ([self upgradeState] != SSYCurrentRev) {
+        // Get a nice, clean, filtered versionString of the form "major.minor.bugFix" using SSVersionTriplet methods
+        SSYVersionTriplet* currentVersionTriplet = [SSYVersionTriplet versionTripletFromBundleIdentifier:[[NSBundle mainBundle] bundleIdentifier]] ;
+        NSString* currentVersionString = [currentVersionTriplet string] ;
+        
+        // Record currently-launched version into prefs
+        // Note that this must be done AFTER the above reading,
+        // or else the pref constKeyLastVersion will be written as the previous version!
+        NSUserDefaults* userDefaults = [NSUserDefaults standardUserDefaults] ;
+        [userDefaults setObject:currentVersionString
+                         forKey:constKeyLastVersion] ;
+        [userDefaults synchronize] ;
+    }
 }
 
 
@@ -122,5 +118,9 @@ + (SSYVersionTriplet*)previousVersionTriplet {
 	return [[self sharedInfo] previousVersionTriplet] ;
 }
 
++ (void)calculateUpgradeState {
+    [[self sharedInfo] calculateUpgradeState] ;
+}
+
 
 @end