+[GTDiff diffOldIndex:withNewIndex:…]

Wrapper for git_diff_index_to_index to create diffs from two in-memory indeces.

Author: slavikus

ObjectiveGit/GTDiff.h

@@ -218,6 +218,23 @@ typedef NS_OPTIONS(NSInteger, GTDiffFindOptionsFlags) {
 /// Returns a newly created `GTDiff` object or nil on error.
 + (nullable instancetype)diffOldTree:(nullable GTTree *)oldTree withNewIndex:(nullable GTIndex *)newIndex inRepository:(GTRepository *)repository options:(nullable NSDictionary *)options error:(NSError **)error;
 
+/// Create a diff between two `GTIndex`es.
+///
+/// Both instances must be from the same repository, or an exception will be thrown.
+///
+/// oldIndex   - The "left" side of the diff. May be nil to represent an empty
+///              index.
+/// newIndex   - The "right" side of the diff. May be nil to represent an empty
+///              index.
+/// repository - The repository to be used for the diff. Cannot be nil.
+/// options    - A dictionary containing any of the above options key constants, or
+///              nil to use the defaults.
+/// error      - Populated with an `NSError` object on error, if information is
+///              available.
+///
+/// Returns a newly created `GTDiff` object or nil on error.
++ (nullable instancetype)diffOldIndex:(nullable GTIndex *)oldIndex withNewIndex:(nullable GTIndex *)newIndex inRepository:(GTRepository *)repository options:(nullable NSDictionary *)options error:(NSError **)error;
+
 /// Create a diff between a repository's current index.
 ///
 /// This is equivalent to `git diff --cached <treeish>` or if you pass the HEAD

ObjectiveGit/GTDiff.m

@@ -110,6 +110,22 @@ + (instancetype)diffOldTree:(GTTree *)oldTree withNewIndex:(GTIndex *)newIndex i
 	return [[self alloc] initWithGitDiff:diff repository:repository];
 }
 
++ (nullable instancetype)diffOldIndex:(GTIndex *)oldIndex withNewIndex:(GTIndex *)newIndex inRepository:(GTRepository *)repository options:(NSDictionary *)options error:(NSError **)error
+{
+	NSParameterAssert(repository != nil);
+	
+	__block git_diff *diff;
+	int status = [self handleParsedOptionsDictionary:options usingBlock:^(git_diff_options *optionsStruct) {
+		return git_diff_index_to_index(&diff, repository.git_repository, oldIndex.git_index, newIndex.git_index, optionsStruct);
+	}];
+	if (status != GIT_OK) {
+		if (error != NULL) *error = [NSError git_errorFor:status description:@"Failed to create diff between %@ and %@", oldIndex, newIndex];
+		return nil;
+	}
+	
+	return [[self alloc] initWithGitDiff:diff repository:repository];
+}
+
 + (instancetype)diffIndexFromTree:(GTTree *)tree inRepository:(GTRepository *)repository options:(NSDictionary *)options error:(NSError **)error {
 	NSParameterAssert(repository != nil);
 	NSParameterAssert(tree == nil || [tree.repository isEqual:repository]);