Converting [YapDatabaseView findRangeInGroup:usingBlock:blockType:] to modern syntax. (no more explicit blockType parameter)

Author: robbiehanson

YapDatabase/Extensions/Views/Internal/YapDatabaseViewPrivate.h

@@ -56,6 +56,16 @@ static NSString *const changeset_key_changes           = @"changes";
 #pragma mark -
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
+@interface YapDatabaseViewFind ()
+
++ (instancetype)withBlock:(YapDatabaseViewFindBlock)block blockType:(YapDatabaseViewBlockType)blockType;
+
+@end
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+#pragma mark -
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
 @interface YapDatabaseView () {
 @protected
 

YapDatabase/Extensions/Views/YapDatabaseViewTransaction.h

@@ -144,17 +144,6 @@
 
 #pragma mark Finding
 
-typedef id YapDatabaseViewFindBlock; // One of the YapDatabaseViewFindX types below.
-
-typedef NSComparisonResult (^YapDatabaseViewFindWithKeyBlock)      \
-                                                        (NSString *collection, NSString *key);
-typedef NSComparisonResult (^YapDatabaseViewFindWithObjectBlock)   \
-                                                        (NSString *collection, NSString *key, id object);
-typedef NSComparisonResult (^YapDatabaseViewFindWithMetadataBlock) \
-                                                        (NSString *collection, NSString *key, id metadata);
-typedef NSComparisonResult (^YapDatabaseViewFindWithRowBlock)      \
-                                                        (NSString *collection, NSString *key, id object, id metadata);
-
 /**
  * This method uses a binary search algorithm to find a range of items within the view that match the given criteria.
  * For example:
@@ -234,20 +223,20 @@ typedef NSComparisonResult (^YapDatabaseViewFindWithRowBlock)      \
  * @param group
  *     The group within the view to search.
  * 
- * @param block
- *     One of the YapDatabaseViewFindWithXBlock types.
- * 
- * @param blockType
- *     The proper YapDatabaseViewBlockTypeWithX type that matches the given block.
+ * @param find
+ *     Instance of YapDatabaseViewFind. (See YapDatabaseViewTypes.h)
  * 
  * @return
  *     If found, the range that matches the items within the desired range.
  *     That is, is these items were passed to the given block, the block would return NSOrderedSame.
  *     If not found, returns NSMakeRange(NSNotFound, 0).
 **/
+- (NSRange)findRangeInGroup:(NSString *)group using:(YapDatabaseViewFind *)find;
+
 - (NSRange)findRangeInGroup:(NSString *)group
                  usingBlock:(YapDatabaseViewFindBlock)block
-                  blockType:(YapDatabaseViewBlockType)blockType;
+                  blockType:(YapDatabaseViewBlockType)blockType
+__attribute((deprecated("Use method findRangeInGroup:using: instead")));
 
 #pragma mark Enumerating
 

YapDatabase/Extensions/Views/YapDatabaseViewTransaction.m

@@ -4311,16 +4311,9 @@ - (NSString *)versionTag
 /**
  * See header file for extensive documentation for this method.
 **/
-- (NSRange)findRangeInGroup:(NSString *)group
-                 usingBlock:(YapDatabaseViewFindBlock)block
-                  blockType:(YapDatabaseViewBlockType)blockType
+- (NSRange)findRangeInGroup:(NSString *)group using:(YapDatabaseViewFind *)find
 {
-	BOOL invalidBlockType = blockType != YapDatabaseViewBlockTypeWithKey      &&
-	                        blockType != YapDatabaseViewBlockTypeWithObject   &&
-	                        blockType != YapDatabaseViewBlockTypeWithMetadata &&
-	                        blockType != YapDatabaseViewBlockTypeWithRow;
-	
-	if (group == nil || block == NULL || invalidBlockType)
+	if (group == nil || find == NULL)
 	{
 		return NSMakeRange(NSNotFound, 0);
 	}
@@ -4338,9 +4331,11 @@ - (NSRange)findRangeInGroup:(NSString *)group
 		return NSMakeRange(NSNotFound, 0);
 	}
 
-	NSComparisonResult (^compare)(NSUInteger) = ^NSComparisonResult (NSUInteger index){
-		
-		int64_t rowid = 0;
+	// Helper block:
+	//
+	// Finds the rowid for a given index (within the view.group).
+	
+	int64_t (^findRowid)(NSUInteger) = ^int64_t (NSUInteger index){
 
 		NSUInteger pageOffset = 0;
 		for (YapDatabaseViewPageMetadata *pageMetadata in pagesMetadataForGroup)
@@ -4349,59 +4344,92 @@ - (NSRange)findRangeInGroup:(NSString *)group
 			{
 				YapDatabaseViewPage *page = [self pageForPageKey:pageMetadata->pageKey];
 
-				rowid = [page rowidAtIndex:(index - pageOffset)];
-				break;
+				return [page rowidAtIndex:(index - pageOffset)];
 			}
 			else
 			{
 				pageOffset += pageMetadata->count;
 			}
 		}
 
-		if (blockType == YapDatabaseViewBlockTypeWithKey)
+		NSAssert(NO, @"index(%lu) not found !!!", (unsigned long)index);
+		return (int64_t)0;
+	};
+	
+	// Helper block:
+	//
+	// Executes the findBlock against the row represented by the given index (within the view.group).
+	
+	NSComparisonResult (^compare)(NSUInteger);
+		
+	switch (find.findBlockType)
+	{
+		case YapDatabaseViewBlockTypeWithKey :
 		{
 			__unsafe_unretained YapDatabaseViewFindWithKeyBlock findBlock =
-			    (YapDatabaseViewFindWithKeyBlock)block;
-			
-			YapCollectionKey *ck = [databaseTransaction collectionKeyForRowid:rowid];
+			  (YapDatabaseViewFindWithKeyBlock)find.findBlock;
 
-			return findBlock(ck.collection, ck.key);
+			compare = ^NSComparisonResult (NSUInteger index){
+				
+				int64_t rowid = findRowid(index);
+				
+				YapCollectionKey *ck = [databaseTransaction collectionKeyForRowid:rowid];
+				
+				return findBlock(ck.collection, ck.key);
+			};
 		}
-		else if (blockType == YapDatabaseViewBlockTypeWithObject)
+		case YapDatabaseViewBlockTypeWithObject :
 		{
 			__unsafe_unretained YapDatabaseViewFindWithObjectBlock findBlock =
-			    (YapDatabaseViewFindWithObjectBlock)block;
-			
-			YapCollectionKey *ck = nil;
-			id object = nil;
-			[databaseTransaction getCollectionKey:&ck object:&object forRowid:rowid];
+			    (YapDatabaseViewFindWithObjectBlock)find.findBlock;
 
-			return findBlock(ck.collection, ck.key, object);
+			compare = ^NSComparisonResult (NSUInteger index){
+				
+				int64_t rowid = findRowid(index);
+				
+				YapCollectionKey *ck = nil;
+				id object = nil;
+				[databaseTransaction getCollectionKey:&ck object:&object forRowid:rowid];
+				
+				return findBlock(ck.collection, ck.key, object);
+			};
 		}
-		else if (blockType == YapDatabaseViewBlockTypeWithMetadata)
+		case YapDatabaseViewBlockTypeWithMetadata :
 		{
 			__unsafe_unretained YapDatabaseViewFindWithMetadataBlock findBlock =
-			    (YapDatabaseViewFindWithMetadataBlock)block;
-			
-			YapCollectionKey *ck = nil;
-			id metadata = nil;
-			[databaseTransaction getCollectionKey:&ck metadata:&metadata forRowid:rowid];
+			    (YapDatabaseViewFindWithMetadataBlock)find.findBlock;
 
-			return findBlock(ck.collection, ck.key, metadata);
+			compare = ^NSComparisonResult (NSUInteger index){
+				
+				int64_t rowid = findRowid(index);
+				
+				YapCollectionKey *ck = nil;
+				id metadata = nil;
+				[databaseTransaction getCollectionKey:&ck metadata:&metadata forRowid:rowid];
+				
+				return findBlock(ck.collection, ck.key, metadata);
+			};
 		}
-		else
+		default :
 		{
 			__unsafe_unretained YapDatabaseViewFindWithRowBlock findBlock =
-			    (YapDatabaseViewFindWithRowBlock)block;
-			
-			YapCollectionKey *ck = nil;
-			id object = nil;
-			id metadata = nil;
-			[databaseTransaction getCollectionKey:&ck object:&object metadata:&metadata forRowid:rowid];
+			    (YapDatabaseViewFindWithRowBlock)find.findBlock;
 
-			return findBlock(ck.collection, ck.key, object, metadata);
+			compare = ^NSComparisonResult (NSUInteger index){
+				
+				int64_t rowid = findRowid(index);
+				
+				YapCollectionKey *ck = nil;
+				id object = nil;
+				id metadata = nil;
+				[databaseTransaction getCollectionKey:&ck object:&object metadata:&metadata forRowid:rowid];
+				
+				return findBlock(ck.collection, ck.key, object, metadata);
+			};
 		}
-	};
+		
+	} // end switch (blockType)
+		
 
 	NSUInteger loopCount = 0;
 
@@ -4479,6 +4507,17 @@ - (NSRange)findRangeInGroup:(NSString *)group
 	return NSMakeRange(sMin, (eMax - sMin));
 }
 
+/**
+ * This method is deprecated.
+ * Use findRangeInGroup:using: instead.
+**/
+- (NSRange)findRangeInGroup:(NSString *)group
+                 usingBlock:(YapDatabaseViewFindBlock)block
+                  blockType:(YapDatabaseViewBlockType)blockType
+{
+	return [self findRangeInGroup:group using:[YapDatabaseViewFind withBlock:block blockType:blockType]];
+}
+
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 #pragma mark Public API - Enumerating
 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

YapDatabase/Extensions/Views/YapDatabaseViewTypes.h

@@ -51,6 +51,8 @@ typedef NSString* (^YapDatabaseViewGroupingWithRowBlock) \
 
 @end
 
+#pragma mark -
+
 /**
  * The sorting block handles sorting of objects within their group.
  *
@@ -130,3 +132,78 @@ typedef NSComparisonResult (^YapDatabaseViewSortingWithRowBlock)
 @property (nonatomic, assign, readonly) YapDatabaseViewBlockType sortingBlockType;
 
 @end
+
+#pragma mark -
+
+/**
+ * A find block is used to efficiently find items within a view.
+ * It allows you to perform a binary search on the pre-sorted items within a view.
+ * 
+ * The return values from the YapDatabaseViewFindBlock have the following meaning:
+ * 
+ * - NSOrderedAscending : The given row (block parameters) is less than the range I'm looking for.
+ *                        That is, the row would have a smaller index within the view than would the range I seek.
+ * 
+ * - NSOrderedDecending : The given row (block parameters) is greater than the range I'm looking for.
+ *                        That is, the row would have a greater index within the view than would the range I seek.
+ * 
+ * - NSOrderedSame : The given row (block parameters) is within the range I'm looking for.
+ * 
+ * Keep in mind 2 things:
+ * 
+ * #1 : This method can only be used if you need to find items according to their sort order.
+ *      That is, according to how the items are sorted via the view's sortingBlock.
+ *      Attempting to use this method in any other manner makes no sense.
+ *
+ * #2 : The findBlock that you pass needs to be setup in the same manner as the view's sortingBlock.
+ *      That is, the following rules must be followed, or the results will be incorrect:
+ *      
+ *      For example, say you have a view like this, looking for the following range of 3 items:
+ *      myView = @[ A, B, C, D, E, F, G ]
+ *                     ^^^^^^^
+ *      sortingBlock(A, B) => NSOrderedAscending
+ *      findBlock(A)       => NSOrderedAscending
+ *      
+ *      sortingBlock(E, D) => NSOrderedDescending
+ *      findBlock(E)       => NSOrderedDescending
+ * 
+ *      findBlock(B) => NSOrderedSame
+ *      findBlock(C) => NSOrderedSame
+ *      findBlock(D) => NSOrderedSame
+ * 
+ * In other words, you can't sort one way in the sortingBlock, and "sort" another way in the findBlock.
+ * Another way to think about it is in terms of how the Apple docs define the NSOrdered enums:
+ * 
+ * NSOrderedAscending  : The left operand is smaller than the right operand.
+ * NSOrderedDescending : The left operand is greater than the right operand.
+ * 
+ * For the findBlock, the "left operand" is the row that is passed,
+ * and the "right operand" is the desired range.
+ * 
+ * And NSOrderedSame means: "the passed row is within the range I'm looking for".
+**/
+@interface YapDatabaseViewFind : NSObject
+
+typedef id YapDatabaseViewFindBlock; // One of the YapDatabaseViewFindX types below.
+
+typedef NSComparisonResult (^YapDatabaseViewFindWithKeyBlock)      \
+                                 (NSString *collection, NSString *key);
+
+typedef NSComparisonResult (^YapDatabaseViewFindWithObjectBlock)   \
+                                 (NSString *collection, NSString *key, id object);
+
+typedef NSComparisonResult (^YapDatabaseViewFindWithMetadataBlock) \
+                                 (NSString *collection, NSString *key, id metadata);
+
+typedef NSComparisonResult (^YapDatabaseViewFindWithRowBlock)      \
+                                 (NSString *collection, NSString *key, id object, id metadata);
+
++ (instancetype)withKeyBlock:(YapDatabaseViewFindWithKeyBlock)findBlock;
++ (instancetype)withObjectBlock:(YapDatabaseViewFindWithObjectBlock)findBlock;
++ (instancetype)withMetadataBlock:(YapDatabaseViewFindWithMetadataBlock)findBlock;
++ (instancetype)withRowBlock:(YapDatabaseViewFindWithRowBlock)findBlock;
+
+@property (nonatomic, strong, readonly) YapDatabaseViewFindBlock findBlock;
+@property (nonatomic, assign, readonly) YapDatabaseViewBlockType findBlockType;
+
+@end