Out-of-box document-level do not delete support for table rows

couchcocoa.patch

diff --git a/UI/iOS/CouchUITableSource.h b/UI/iOS/CouchUITableSource.h
index c335c99..3f08d1e 100644
--- a/UI/iOS/CouchUITableSource.h
+++ b/UI/iOS/CouchUITableSource.h
@@ -45,6 +45,13 @@
 
 #pragma mark Editing The Table:
 
+/** 
+ * If non-nil, specifies the property name of the query row's value that will be used
+ * to determine if a doc explicitly forbids its own deletion as a row by UI gestures?
+ * If this is not set then deletionAllowed property is put to use.
+ */
+@property (copy) NSString* doNotDeleteProperty;
+
 /** Is the user allowed to delete rows by UI gestures? (Defaults to YES.) */
 @property (nonatomic) BOOL deletionAllowed;
 
diff --git a/UI/iOS/CouchUITableSource.m b/UI/iOS/CouchUITableSource.m
index 7b9546a..10d3e6d 100644
--- a/UI/iOS/CouchUITableSource.m
+++ b/UI/iOS/CouchUITableSource.m
@@ -17,6 +17,7 @@
     CouchLiveQuery* _query;
   NSMutableArray* _rows;
     NSString* _labelProperty;
+    NSString* _doNotDeleteProperty;
     BOOL _deletionAllowed;
 }
 @end
@@ -136,6 +137,7 @@
 
 
 @synthesize labelProperty=_labelProperty;
+@synthesize doNotDeleteProperty=_doNotDeleteProperty;
 
 
 - (NSString*) labelForRow: (CouchQueryRow*)row {
@@ -191,7 +193,17 @@
 
 
 - (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
-    return _deletionAllowed;
+    if (_doNotDeleteProperty != nil) { // per document setting
+        CouchQueryRow* row = [self rowAtIndex: indexPath.row];
+        id value = [row.document propertyForKey: _doNotDeleteProperty];
+        if (value != [NSNull null] && value) {
+            return false; // if the document must not not be deleted, return false here
+        } else {
+            return true; // if the document may be deleted, return true here
+        }
+    } else { // global setting
+        return _deletionAllowed;
+    }
 }