GTOID improvements

Classes/GTOID.h

@@ -9,7 +9,7 @@
 #import "git2.h"
 
 // Represents an object ID.
-@interface GTOID : NSObject
+@interface GTOID : NSObject <NSCopying>
 
 // The SHA pointed to by the OID.
 @property (nonatomic, readonly, copy) NSString *SHA;
@@ -28,6 +28,40 @@
 // Returns the initialized receiver.
 - (id)initWithSHA:(NSString *)SHA;
 
+// Initializes the receiver by converting the given SHA to an OID
+// optionally returning a NSError instance on failure.
+//
+// SHA   - The to convert to an OID. Cannot be nil.
+// error - Will be filled with an error object in if the SHA cannot be parsed
+//
+// Returns the initialized receiver or nil if an error occured.
+- (id)initWithSHA:(NSString *)SHA error:(NSError **)error;
+
+// Initializes the receiver by converting the given SHA C string to an OID.
+//
+// string - The C string to convert. Cannot be NULL.
+//
+// Returns the initialized receiver.
+- (id)initWithSHACString:(const char *)string;
+
+// Initializes the receiver by converting the given SHA C string to an OID
+// optionally returning a NSError instance on failure.
+//
+// string - The C string to convert. Cannot be NULL.
+// error  - Will be filled with an error object in if the SHA cannot be parsed
+//
+// Returns the initialized receiver.
+- (id)initWithSHACString:(const char *)string error:(NSError **)error;
+
+// Creates a new instance with the given git_oid using initWithGitOid:
++ (instancetype)oidWithGitOid:(const git_oid *)git_oid;
+
+// Creates a new instance from the given SHA string using initWithSHAString:
++ (instancetype)oidWithSHA:(NSString *)SHA;
+
+// Creates a new instance from the given SHA C string using initWithSHACString:
++ (instancetype)oidWithSHACString:(const char *)SHA;
+
 // Returns the underlying git_oid struct.
 - (const git_oid *)git_oid __attribute__((objc_returns_inner_pointer));
 

Classes/GTOID.m

@@ -7,6 +7,7 @@
 //
 
 #import "GTOID.h"
+#import "NSError+Git.h"
 
 @interface GTOID () {
 	git_oid _git_oid;
@@ -46,18 +47,48 @@ - (id)initWithGitOid:(const git_oid *)oid {
 	return self;
 }
 
-- (id)initWithSHA:(NSString *)SHA {
+- (id)initWithSHA:(NSString *)SHA error:(NSError **)error {
 	NSParameterAssert(SHA != nil);
+	return [self initWithSHACString:SHA.UTF8String error:error];
+}
+
+- (id)initWithSHA:(NSString *)SHA {
+	return [self initWithSHA:SHA error:NULL];
+}
 
+- (id)initWithSHACString:(const char *)string error:(NSError **)error {
+	NSParameterAssert(string != NULL);
+
 	self = [super init];
 	if (self == nil) return nil;
-
-	int status = git_oid_fromstr(&_git_oid, SHA.UTF8String);
-	if (status != GIT_OK) return nil;
+
+	int status = git_oid_fromstr(&_git_oid, string);
+	if (status != GIT_OK) {
+		if (error != NULL) {
+			*error = [NSError git_errorFor:status withAdditionalDescription:[NSString stringWithFormat:@"Failed to convert string '%s' to object id", string]];
+		}
+		return nil;
+	}
 
 	return self;
 }
 
+- (id)initWithSHACString:(const char *)string {
+	return [self initWithSHACString:string error:NULL];
+}
+
++ (instancetype)oidWithGitOid:(const git_oid *)git_oid {
+	return [[self alloc] initWithGitOid:git_oid];
+}
+
++ (instancetype)oidWithSHA:(NSString *)SHA {
+	return [[self alloc] initWithSHA:SHA];
+}
+
++ (instancetype)oidWithSHACString:(const char *)SHA {
+	return [[self alloc] initWithSHACString:SHA];
+}
+
 #pragma mark NSObject
 
 - (NSString *)description {
@@ -77,4 +108,9 @@ - (BOOL)isEqual:(GTOID *)object {
 	return (BOOL)git_oid_equal(self.git_oid, object.git_oid);
 }
 
+- (id)copyWithZone:(NSZone *)zone {
+	// Optimization: Since this class is immutable we don't need to create an actual copy.
+	return self;
+}
+
 @end

ObjectiveGitTests/GTOIDSpec.m

@@ -32,6 +32,10 @@
 		NSString *secondSHA = @"82dc47f6ba3beecab33080a1136d8913098e1801";
 		expect(testOID).notTo.equal([[GTOID alloc] initWithSHA:secondSHA]);
 	});
+
+	it(@"should compare equal to an OID created with the same SHA from a C string", ^{
+		expect(testOID).to.equal([[GTOID alloc] initWithSHACString:"f7ecd8f4404d3a388efbff6711f1bdf28ffd16a0"]);
+	});
 });
 
 it(@"should keep the git_oid alive even if the object goes out of scope", ^{
@@ -46,4 +50,28 @@
 	expect(testOID.SHA).to.equal(testSHA);
 });
 
+it(@"should return an error when initialized with an empty SHA string", ^{
+	NSError *error = nil;
+	GTOID *oid = [[GTOID alloc] initWithSHA:@"" error:&error];
+
+	expect(oid).to.beNil();
+	expect(error).notTo.beNil();
+});
+
+it(@"should return an error when initialized with a string that contains non-hex characters", ^{
+	NSError *error = nil;
+	GTOID *oid = [[GTOID alloc] initWithSHA:@"zzzzz8f4404d3a388efbff6711f1bdf28ffd16a0" error:&error];
+
+	expect(oid).to.beNil();
+	expect(error).notTo.beNil();
+});
+
+it(@"should return an error when initialized with a string shorter than 40 characters", ^{
+	NSError *error = nil;
+	GTOID *oid = [[GTOID alloc] initWithSHA:@"f7ecd80" error:&error];
+
+	expect(oid).to.beNil();
+	expect(error).notTo.beNil();
+});
+
 SpecEnd