adium-1.4 3331:3c7515d4ce40: Added a MessageViewVersion_MinimumC...

[commits at adium.im]

details:	http://hg.adium.im/adium-1.4/rev/3c7515d4ce40
revision:	3331:3c7515d4ce40
author:		Evan Schoenberg
date:		Wed Jan 26 21:02:18 2011 -0600

Added a MessageViewVersion_MinimumCompatible key to message style Info.plist keys. If set, Adium will refuse to load the style if it has a minimum version greater than its latest known version.  This way, a message style which depends upon a hypothetical future version 5 message style can gracefully fail to load in Adium 1.4.2 which knows nothing of it; however, a message style using version 5 which is backwards compatible with version 4 can still be loaded. Fixes #7438 (for future iterations of the problem; nothing can be done for the described historical incompatibility).
(transplanted from c7323a40d94faaf031aa01ed0e9ec63dadfde954)

diffs (114 lines):

diff -r 2cb58ee83c27 -r 3c7515d4ce40 Plugins/WebKit Message View/AIWebKitMessageViewPlugin.m
--- a/Plugins/WebKit Message View/AIWebKitMessageViewPlugin.m	Tue Jan 25 18:58:45 2011 -0600
+++ b/Plugins/WebKit Message View/AIWebKitMessageViewPlugin.m	Wed Jan 26 21:02:18 2011 -0600
@@ -197,11 +197,22 @@
 																							group:loadFromGroup]];
 		if(!*thisStyle) {
 			/* If the path isn't cached yet, load the style and then store the path */
-			*thisStyle = [AIWebkitMessageViewStyle messageViewStyleFromBundle:[self messageStyleBundleWithIdentifier:[prefs preferenceForKey:KEY_WEBKIT_STYLE
-																																		   group:loadFromGroup]]];
-			[prefs setPreference:[[[*thisStyle bundle] bundlePath] stringByCollapsingBundlePath]
-						  forKey:KEY_CURRENT_WEBKIT_STYLE_PATH
-						   group:loadFromGroup];
+			*thisStyle = [AIWebkitMessageViewStyle messageViewStyleFromBundle:
+                          [self messageStyleBundleWithIdentifier:[prefs preferenceForKey:KEY_WEBKIT_STYLE
+                                                                                   group:loadFromGroup]]];
+            if (*thisStyle) {
+                [prefs setPreference:[[[*thisStyle bundle] bundlePath] stringByCollapsingBundlePath]
+                              forKey:KEY_CURRENT_WEBKIT_STYLE_PATH
+                               group:loadFromGroup];
+            } else {
+                /* If the style failed to load, clear our preference to fall back to the default */
+                /* XXX An error message could potentially be displayed here */
+                [prefs setPreference:nil forKey:KEY_WEBKIT_STYLE group:loadFromGroup];
+                
+                *thisStyle = [AIWebkitMessageViewStyle messageViewStyleFromBundle:
+                              [self messageStyleBundleWithIdentifier:[prefs preferenceForKey:KEY_WEBKIT_STYLE
+                                                                                       group:loadFromGroup]]];
+            }
 		}
 		[*thisStyle retain];
 	}
diff -r 2cb58ee83c27 -r 3c7515d4ce40 Plugins/WebKit Message View/AIWebkitMessageViewStyle.h
--- a/Plugins/WebKit Message View/AIWebkitMessageViewStyle.h	Tue Jan 25 18:58:45 2011 -0600
+++ b/Plugins/WebKit Message View/AIWebkitMessageViewStyle.h	Wed Jan 26 21:02:18 2011 -0600
@@ -147,8 +147,10 @@
 
 /*!
  *  @brief Reloads the content of the style, useful for style authors and updates
+ *
+ *  @result YES if the style loaded succesfully; NO if an error (such as an incompatible style version) occurred.
  */
-- (void) reloadStyle;
+- (BOOL) reloadStyle;
 
 /*!
  *  @brief The name of the active variant.
diff -r 2cb58ee83c27 -r 3c7515d4ce40 Plugins/WebKit Message View/AIWebkitMessageViewStyle.m
--- a/Plugins/WebKit Message View/AIWebkitMessageViewStyle.m	Tue Jan 25 18:58:45 2011 -0600
+++ b/Plugins/WebKit Message View/AIWebkitMessageViewStyle.m	Wed Jan 26 21:02:18 2011 -0600
@@ -39,9 +39,11 @@
 
 //
 #define LEGACY_VERSION_THRESHOLD		3	//Styles older than this version are considered legacy
+#define MAX_KNOWN_WEBKIT_VERSION        4   //Styles newer than this version are unknown entities
 
 //
 #define KEY_WEBKIT_VERSION				@"MessageViewVersion"
+#define KEY_WEBKIT_VERSION_MIN			@"MessageViewVersion_MinimumCompatible"
 
 //BOM scripts for appending content.
 #define APPEND_MESSAGE_WITH_SCROLL		@"checkIfScrollToBottomIsNeeded(); appendMessage(\"%@\"); scrollToBottomIfNeeded();"
@@ -142,19 +144,20 @@
 	if ((self = [super init])) {
 		styleBundle = [inBundle retain];
 		stylePath = [[styleBundle resourcePath] retain];
-		[self reloadStyle];
+        
+		if ([self reloadStyle] == FALSE) {
+            [self release];
+            return nil;
+        }
 	}
 
 	return self;
 }
 
-- (void) reloadStyle
+- (BOOL) reloadStyle
 {
 	[self releaseResources];
 	
-	//Default behavior
-	allowTextBackgrounds = YES;
-	
 	/* Our styles are versioned so we can change how they work without breaking compatibility.
 	 *
 	 * Version 0: Initial Webkit Version
@@ -173,6 +176,17 @@
 	 */
 	styleVersion = [[styleBundle objectForInfoDictionaryKey:KEY_WEBKIT_VERSION] integerValue];
 	
+    /* Refuse to load a version whose minimum compatible version is greater than the latest version we know about; that
+     * indicates this is a style FROM THE FUTURE, and we can't risk corrupting our own timeline.
+     */
+    NSInteger minimumCompatibleVersion = [[styleBundle objectForInfoDictionaryKey:KEY_WEBKIT_VERSION_MIN] integerValue];
+    if (minimumCompatibleVersion && (minimumCompatibleVersion > MAX_KNOWN_WEBKIT_VERSION)) {
+        return NO;
+    }
+
+    //Default behavior
+	allowTextBackgrounds = YES;
+
 	//Pre-fetch our templates
 	[self _loadTemplates];
 	
@@ -191,6 +205,8 @@
 	
 	NSNumber *allowsColorsNumber = [styleBundle objectForInfoDictionaryKey:@"AllowTextColors"];
 	allowsColors = (allowsColorsNumber ? [allowsColorsNumber boolValue] : YES);
+    
+    return YES;
 }
 
 /*!