Pull

ObjectiveGit/GTRemote.m

@@ -95,6 +95,10 @@ - (NSUInteger)hash {
 	return self.name.hash ^ self.URLString.hash;
 }
 
+- (NSString *)description {
+	return [NSString stringWithFormat:@"<%@: %p> name: %@, URLString: %@", NSStringFromClass([self class]), self, self.name, self.URLString];
+}
+
 #pragma mark API
 
 + (BOOL)isValidRemoteName:(NSString *)name {

ObjectiveGit/GTRepository+Pull.h

@@ -0,0 +1,56 @@
+//
+//  GTRepository+Pull.h
+//  ObjectiveGitFramework
+//
+//  Created by Ben Chatelain on 6/17/15.
+//  Copyright © 2015 GitHub, Inc. All rights reserved.
+//
+
+#import "GTRepository.h"
+#import "git2/merge.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+/// An enum describing the result of the merge analysis.
+/// See `git_merge_analysis_t`.
+typedef NS_ENUM(NSInteger, GTMergeAnalysis) {
+	GTMergeAnalysisNone = GIT_MERGE_ANALYSIS_NONE,
+	GTMergeAnalysisNormal = GIT_MERGE_ANALYSIS_NORMAL,
+	GTMergeAnalysisUpToDate = GIT_MERGE_ANALYSIS_UP_TO_DATE,
+	GTMergeAnalysisUnborn = GIT_MERGE_ANALYSIS_UNBORN,
+	GTMergeAnalysisFastForward = GIT_MERGE_ANALYSIS_FASTFORWARD,
+};
+
+typedef void (^GTRemoteFetchTransferProgressBlock)(const git_transfer_progress *progress, BOOL *stop);
+
+@interface GTRepository (Pull)
+
+#pragma mark - Pull
+
+/// Pull a single branch from a remote.
+///
+/// branch        - The branch to pull.
+/// remote        - The remote to pull from.
+/// options       - Options applied to the fetch operation.
+///                 Recognized options are:
+///                 `GTRepositoryRemoteOptionsCredentialProvider`
+/// error         - The error if one occurred. Can be NULL.
+/// progressBlock - An optional callback for monitoring progress.
+///
+/// Returns YES if the pull was successful, NO otherwise (and `error`, if provided,
+/// will point to an error describing what happened).
+- (BOOL)pullBranch:(GTBranch *)branch fromRemote:(GTRemote *)remote withOptions:(nullable NSDictionary *)options error:(NSError **)error progress:(nullable GTRemoteFetchTransferProgressBlock)progressBlock;
+
+/// Analyze which merge to perform.
+///
+/// analysis   - The resulting analysis.
+/// fromBranch - The branch to merge from.
+/// error      - The error if one occurred. Can be NULL.
+///
+/// Returns YES if the analysis was successful, NO otherwise (and `error`, if provided,
+/// will point to an error describing what happened).
+- (BOOL)analyzeMerge:(GTMergeAnalysis *)analysis fromBranch:(GTBranch *)fromBranch error:(NSError **)error;
+
+@end
+
+NS_ASSUME_NONNULL_END

ObjectiveGit/GTRepository+Pull.m

@@ -0,0 +1,168 @@
+//
+//  GTRepository+Pull.m
+//  ObjectiveGitFramework
+//
+//  Created by Ben Chatelain on 6/17/15.
+//  Copyright © 2015 GitHub, Inc. All rights reserved.
+//
+
+#import "GTRepository+Pull.h"
+
+#import "GTCommit.h"
+#import "GTIndex.h"
+#import "GTOID.h"
+#import "GTRemote.h"
+#import "GTReference.h"
+#import "GTRepository+Committing.h"
+#import "GTRepository+RemoteOperations.h"
+#import "GTTree.h"
+#import "NSError+Git.h"
+#import "git2/errors.h"
+
+@implementation GTRepository (Pull)
+
+#pragma mark - Pull
+
+- (BOOL)pullBranch:(GTBranch *)branch fromRemote:(GTRemote *)remote withOptions:(NSDictionary *)options error:(NSError **)error progress:(GTRemoteFetchTransferProgressBlock)progressBlock {
+	NSParameterAssert(branch != nil);
+	NSParameterAssert(remote != nil);
+
+	GTRepository *repo = branch.repository;
+
+	if (![self fetchRemote:remote withOptions:options error:error progress:progressBlock]) {
+		return NO;
+	}
+
+	// Get tracking branch after fetch so that it is up-to-date and doesn't need to be refreshed from disk
+	GTBranch *trackingBranch;
+	if (branch.branchType == GTBranchTypeLocal) {
+		BOOL success = NO;
+		trackingBranch = [branch trackingBranchWithError:error success:&success];
+		if (!success) {
+			if (error != NULL) *error = [NSError git_errorFor:GIT_ERROR description:@"Tracking branch not found for %@", branch.name];
+			return NO;
+		}
+		else if (!trackingBranch) {
+			// Error should already be provided by libgit2
+			return NO;
+		}
+	}
+	else {
+		// When given a remote branch, use it as the tracking branch
+		trackingBranch = branch;
+	}
+
+	// Check if merge is necessary
+	GTBranch *localBranch = [repo currentBranchWithError:error];
+	if (!localBranch) {
+		return NO;
+	}
+
+	GTCommit *localCommit = [localBranch targetCommitWithError:error];
+	if (!localCommit) {
+		return NO;
+	}
+
+	GTCommit *remoteCommit = [trackingBranch targetCommitWithError:error];
+	if (!remoteCommit) {
+		return NO;
+	}
+
+	if ([localCommit.SHA isEqualToString:remoteCommit.SHA]) {
+		// Local and remote tracking branch are already in sync
+		return YES;
+	}
+
+	GTMergeAnalysis analysis = GTMergeAnalysisNone;
+	BOOL success = [self analyzeMerge:&analysis fromBranch:trackingBranch error:error];
+	if (!success) {
+		return NO;
+	}
+
+	if (analysis & GTMergeAnalysisUpToDate) {
+		// Nothing to do
+		return YES;
+	} else if (analysis & GTMergeAnalysisFastForward ||
+			   analysis & GTMergeAnalysisUnborn) {
+		// Fast-forward branch
+		NSString *message = [NSString stringWithFormat:@"merge %@/%@: Fast-forward", remote.name, trackingBranch.name];
+		GTReference *reference = [localBranch.reference referenceByUpdatingTarget:remoteCommit.SHA message:message error:error];
+		BOOL checkoutSuccess = [self checkoutReference:reference strategy:GTCheckoutStrategyForce error:error progressBlock:nil];
+
+		return checkoutSuccess;
+	} else if (analysis & GTMergeAnalysisNormal) {
+		// Do normal merge
+		GTTree *localTree = localCommit.tree;
+		GTTree *remoteTree = remoteCommit.tree;
+
+		// TODO: Find common ancestor
+		GTTree *ancestorTree = nil;
+
+		// Merge
+		GTIndex *index = [localTree merge:remoteTree ancestor:ancestorTree error:error];
+		if (!index) {
+			return NO;
+		}
+
+		// Check for conflict
+		if (index.hasConflicts) {
+			if (error != NULL) *error = [NSError git_errorFor:GIT_ECONFLICT description:@"Merge conflict, pull aborted"];
+			return NO;
+		}
+
+		GTTree *newTree = [index writeTreeToRepository:repo error:error];
+		if (!newTree) {
+			return NO;
+		}
+
+		// Create merge commit
+		NSString *message = [NSString stringWithFormat:@"Merge branch '%@'", localBranch.shortName];
+		NSArray *parents = @[ localCommit, remoteCommit ];
+
+		// FIXME: This is stepping on the local tree
+		GTCommit *mergeCommit = [repo createCommitWithTree:newTree  message:message parents:parents updatingReferenceNamed:localBranch.name error:error];
+		if (!mergeCommit) {
+			return NO;
+		}
+
+		BOOL success = [self checkoutReference:localBranch.reference strategy:GTCheckoutStrategyForce error:error progressBlock:nil];
+		return success;
+	}
+
+	return NO;
+}
+
+- (BOOL)analyzeMerge:(GTMergeAnalysis *)analysis fromBranch:(GTBranch *)fromBranch error:(NSError **)error {
+	NSParameterAssert(analysis != NULL);
+	NSParameterAssert(fromBranch != nil);
+
+	GTCommit *fromCommit = [fromBranch targetCommitWithError:error];
+	if (!fromCommit) {
+		return NO;
+	}
+
+	git_annotated_commit *annotatedCommit;
+
+	int gitError = git_annotated_commit_lookup(&annotatedCommit, self.git_repository, fromCommit.OID.git_oid);
+	if (gitError != GIT_OK) {
+		if (error != NULL) *error = [NSError git_errorFor:gitError description:@"Failed to lookup annotated comit for %@", fromCommit];
+		return NO;
+	}
+
+	// Allow fast-forward or normal merge
+	git_merge_preference_t preference = GIT_MERGE_PREFERENCE_NONE;
+
+	// Merge analysis
+	gitError = git_merge_analysis((git_merge_analysis_t *)analysis, &preference, self.git_repository, (const git_annotated_commit **) &annotatedCommit, 1);
+	if (gitError != GIT_OK) {
+		if (error != NULL) *error = [NSError git_errorFor:gitError description:@"Failed to analyze merge"];
+		return NO;
+	}
+
+	// Cleanup
+	git_annotated_commit_free(annotatedCommit);
+
+	return YES;
+}
+
+@end

ObjectiveGit/GTRepository.m

@@ -91,6 +91,9 @@ @interface GTRepository ()
 @implementation GTRepository
 
 - (NSString *)description {
+	if (self.isBare) {
+		return [NSString stringWithFormat:@"<%@: %p> (bare) gitDirectoryURL: %@", self.class, self, self.gitDirectoryURL];
+	}
 	return [NSString stringWithFormat:@"<%@: %p> fileURL: %@", self.class, self, self.fileURL];
 }
 
@@ -366,7 +369,11 @@ - (GTReference *)headReferenceWithError:(NSError **)error {
 	git_reference *headRef;
 	int gitError = git_repository_head(&headRef, self.git_repository);
 	if (gitError != GIT_OK) {
-		if (error != NULL) *error = [NSError git_errorFor:gitError description:@"Failed to get HEAD"];
+		NSString *unborn = @"";
+		if (gitError == GIT_EUNBORNBRANCH) {
+			unborn = @" (unborn)";
+		}
+		if (error != NULL) *error = [NSError git_errorFor:gitError description:@"Failed to get HEAD%@", unborn];
 		return nil;
 	}
 

ObjectiveGit/ObjectiveGit.h

@@ -40,6 +40,7 @@ FOUNDATION_EXPORT const unsigned char ObjectiveGitVersionString[];
 #import <ObjectiveGit/GTRepository+References.h>
 #import <ObjectiveGit/GTRepository+RemoteOperations.h>
 #import <ObjectiveGit/GTRepository+Reset.h>
+#import <ObjectiveGit/GTRepository+Pull.h>
 #import <ObjectiveGit/GTEnumerator.h>
 #import <ObjectiveGit/GTCommit.h>
 #import <ObjectiveGit/GTCredential.h>