Merge pull request #424 from wordpress-mobile/issue/423-prevent-index-overflows

Issue/423 prevent index overflows

Author: joshheald

CHANGELOG.md

@@ -48,6 +48,12 @@ _None._
 
 _None._
 
+## 1.8.12
+
+### Bug Fixes
+
+- Prevent crash when unexpected indexes received in a PHAsset changeset [#423]
+
 ## 1.8.11
 
 ### Bug Fixes

Example/Podfile.lock

@@ -1,5 +1,5 @@
 PODS:
-  - WPMediaPicker (1.8.11)
+  - WPMediaPicker (1.8.12)
 
 DEPENDENCIES:
   - WPMediaPicker (from `../`)
@@ -9,7 +9,7 @@ EXTERNAL SOURCES:
     :path: "../"
 
 SPEC CHECKSUMS:
-  WPMediaPicker: 79548964e9c7e131ccfa72270bdda3aec8fa56b5
+  WPMediaPicker: e9eaa804e1b0288d7969776608053ae0ea2941f2
 
 PODFILE CHECKSUM: 31590cb12765a73c9da27d6ea5b8b127c095d71d
 

Pod/Classes/WPPHAssetDataSource.m

@@ -97,8 +97,9 @@ - (void)photoLibraryDidChange:(PHChange *)changeInstance
         BOOL incrementalChanges = assetsChangeDetails.hasIncrementalChanges;
         // Capture removed, changed, and moved indexes before fetching results for incremental chaanges.
         // The adjustedIndex depends on the *old* asset count.
-        NSIndexSet *removedIndexes = [self adjustedIndexesForIndexSet:assetsChangeDetails.removedIndexes];
-        NSIndexSet *changedIndexes = [self adjustedIndexesForIndexSet:assetsChangeDetails.changedIndexes];
+        NSInteger oldCount = assetsChangeDetails.fetchResultBeforeChanges.count;
+        NSIndexSet *removedIndexes = [self adjustedIndexesForIndexSet:assetsChangeDetails.removedIndexes forCount:oldCount];
+        NSIndexSet *changedIndexes = [self adjustedIndexesForIndexSet:assetsChangeDetails.changedIndexes forCount:oldCount];
         NSMutableArray *moves = [NSMutableArray array];
         if  (assetsChangeDetails.hasMoves) {
             [assetsChangeDetails enumerateMovesWithBlock:^(NSUInteger fromIndex, NSUInteger toIndex) {
@@ -360,7 +361,11 @@ - (NSInteger)adjustedIndexForIndex:(NSInteger)index forCount:(NSInteger)count
     // Adjust the index so items are returned in reverse order.
     // We do this, rather than specifying the sort order in PHFetchOptions,
     // to preserve the sort order of assets in the Photos app (only in reverse).
-    return (count - 1) - index;
+    if (index < count) {
+        return (count - 1) - index;
+    } else {
+        @throw NSRangeException;
+    }
 }
 
 - (NSIndexSet *)adjustedIndexesForIndexSet:(NSIndexSet *)indexes
@@ -373,8 +378,11 @@ - (NSIndexSet *)adjustedIndexesForIndexSet:(NSIndexSet *)indexes forCount:(NSInt
 {
     NSMutableIndexSet *adjustedSet = [NSMutableIndexSet new];
     [indexes enumerateIndexesUsingBlock:^(NSUInteger idx, BOOL * _Nonnull stop) {
-        if (idx != NSNotFound) {
-            [adjustedSet addIndex:[self adjustedIndexForIndex:idx forCount: count]];
+        if (idx < count) {
+            NSInteger adjustedIndex = [self adjustedIndexForIndex:idx forCount: count];
+            if (adjustedIndex < NSNotFound) {
+                [adjustedSet addIndex:adjustedIndex];
+            }
         }
     }];
 

WPMediaPicker.podspec

@@ -2,7 +2,7 @@
 
 Pod::Spec.new do |s|
   s.name          = 'WPMediaPicker'
-  s.version       = '1.8.11'
+  s.version       = '1.8.12'
 
   s.summary       = 'WPMediaPicker is an iOS controller that allows capture and picking of media assets.'
   s.description   = <<-DESC