Add ahead/behind count and enumeration over OIDs

Author: jspahrsummers

ObjectiveGit/GTBranch.m

@@ -146,22 +146,7 @@ - (GTBranchType)branchType {
 }
 
 - (NSArray *)uniqueCommitsRelativeToBranch:(GTBranch *)otherBranch error:(NSError **)error {
-	NSParameterAssert(otherBranch != nil);
-	
-	GTCommit *mergeBase = [self.repository mergeBaseBetweenFirstOID:self.reference.OID secondOID:otherBranch.reference.OID error:error];
-	if (mergeBase == nil) return nil;
-	
-	GTEnumerator *enumerator = [[GTEnumerator alloc] initWithRepository:self.repository error:error];
-	if (enumerator == nil) return nil;
-	
-	[enumerator resetWithOptions:GTEnumeratorOptionsTimeSort];
-	
-	BOOL success = [enumerator pushSHA:self.OID.SHA error:error];
-	if (!success) return nil;
-
-	success = [enumerator hideSHA:mergeBase.OID.SHA error:error];
-	if (!success) return nil;
-
+	GTEnumerator *enumerator = [self.repository enumerateUniqueCommitsUpToOID:self.OID relativeToOID:otherBranch.OID error:error];
 	return [enumerator allObjectsWithError:error];
 }
 
@@ -225,19 +210,7 @@ - (GTBranch *)reloadedBranchWithError:(NSError **)error {
 }
 
 - (BOOL)calculateAhead:(size_t *)ahead behind:(size_t *)behind relativeTo:(GTBranch *)branch error:(NSError **)error {
-	if (branch == nil) {
-		*ahead = 0;
-		*behind = 0;
-		return YES;
-	}
-
-	int errorCode = git_graph_ahead_behind(ahead, behind, self.repository.git_repository, self.reference.git_oid, branch.reference.git_oid);
-	if (errorCode != GIT_OK && error != NULL) {
-		*error = [NSError git_errorFor:errorCode description:@"Failed to calculate ahead/behind count of %@ relative to %@", self, branch];
-		return NO;
-	}
-
-	return YES;
+	return [self.repository calculateAhead:ahead behind:behind ofOID:self.OID relativeToOID:branch.OID error:error];
 }
 
 @end

ObjectiveGit/GTRepository.h

@@ -498,4 +498,16 @@ extern NSString * const GTRepositoryInitOptionsOriginURLString;
 /// distinguished using the value of `success`.
 - (GTFilterList *)filterListWithPath:(NSString *)path blob:(GTBlob *)blob mode:(GTFilterSourceMode)mode options:(GTFilterListOptions)options success:(BOOL *)success error:(NSError **)error;
 
+/// Creates an enumerator for finding all commits in the history of `headOID`
+/// that do not exist in the history of `baseOID`.
+///
+/// Returns the created enumerator upon success, or `nil` if an error occurred.
+- (GTEnumerator *)enumerateUniqueCommitsUpToOID:(GTOID *)headOID relativeToOID:(GTOID *)baseOID error:(NSError **)error;
+
+/// Calculates how far ahead/behind the commit represented by `headOID` is,
+/// relative to the commit represented by `baseOID`.
+///
+/// Returns whether `ahead` and `behind` were successfully calculated.
+- (BOOL)calculateAhead:(size_t *)ahead behind:(size_t *)behind ofOID:(GTOID *)headOID relativeToOID:(GTOID *)baseOID error:(NSError **)error;
+
 @end

ObjectiveGit/GTRepository.m

@@ -885,4 +885,36 @@ - (GTFilterList *)filterListWithPath:(NSString *)path blob:(GTBlob *)blob mode:(
 	}
 }
 
+- (GTEnumerator *)enumerateUniqueCommitsUpToOID:(GTOID *)headOID relativeToOID:(GTOID *)baseOID error:(NSError **)error {
+	NSParameterAssert(headOID != nil);
+	NSParameterAssert(baseOID != nil);
+	
+	GTCommit *mergeBase = [self mergeBaseBetweenFirstOID:headOID secondOID:baseOID error:error];
+	if (mergeBase == nil) return nil;
+	
+	GTEnumerator *enumerator = [[GTEnumerator alloc] initWithRepository:self error:error];
+	if (enumerator == nil) return nil;
+	
+	[enumerator resetWithOptions:GTEnumeratorOptionsTimeSort];
+	
+	if (![enumerator pushSHA:headOID.SHA error:error]) return nil;
+	if (![enumerator hideSHA:mergeBase.OID.SHA error:error]) return nil;
+
+	return enumerator;
+}
+
+- (BOOL)calculateAhead:(size_t *)ahead behind:(size_t *)behind ofOID:(GTOID *)headOID relativeToOID:(GTOID *)baseOID error:(NSError **)error {
+	NSParameterAssert(headOID != nil);
+	NSParameterAssert(baseOID != nil);
+
+	int errorCode = git_graph_ahead_behind(ahead, behind, self.git_repository, headOID.git_oid, baseOID.git_oid);
+	if (errorCode != GIT_OK) {
+		if (error != NULL) *error = [NSError git_errorFor:errorCode description:@"Failed to calculate ahead/behind count of %@ relative to %@", headOID, baseOID];
+
+		return NO;
+	}
+
+	return YES;
+}
+
 @end