OctagonStateMachineHelpers.m   [plain text]

/*
* Copyright (c) 2018 Apple Inc. All Rights Reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/

#if OCTAGON

#import "keychain/ot/OTStates.h"
#import "keychain/ot/ObjCImprovements.h"
#import "keychain/ot/OTDefines.h"
#import "keychain/ot/OTConstants.h"
#import "keychain/categories/NSError+UsefulConstructors.h"
#import "keychain/ckks/CloudKitCategories.h"
#import "keychain/ckks/CKKS.h"

OctagonState* const OctagonStateMachineNotStarted = (OctagonState*) @"not_started";
OctagonState* const OctagonStateMachineHalted = (OctagonState*) @"halted";

#pragma mark -- OctagonStateTransitionOperation

@implementation OctagonStateTransitionOperation
- (instancetype)initIntending:(OctagonState*)intendedState
errorState:(OctagonState*)errorState
{
if((self = [super init])) {
_nextState = errorState;
_intendedState = intendedState;
}
return self;
}

- (NSString*)description
{
return [NSString stringWithFormat:@"<OctagonStateTransitionOperation(%@): intended:%@ actual:%@>", self.name, self.intendedState, self.nextState];
}

+ (instancetype)named:(NSString*)name
intending:(OctagonState*)intendedState
errorState:(OctagonState*)errorState
withBlockTakingSelf:(void(^)(OctagonStateTransitionOperation* op))block
{
OctagonStateTransitionOperation* op = [[self alloc] initIntending:intendedState
errorState:errorState];
WEAKIFY(op);
[op addExecutionBlock:^{
STRONGIFY(op);
block(op);
}];
op.name = name;
return op;
}

+ (instancetype)named:(NSString*)name
entering:(OctagonState*)intendedState
{
OctagonStateTransitionOperation* op = [[self alloc] initIntending:intendedState
errorState:intendedState];
op.name = name;
return op;
}

@end

#pragma mark -- OctagonStateTransitionGroupOperation

@implementation OctagonStateTransitionGroupOperation
- (instancetype)initIntending:(OctagonState*)intendedState
errorState:(OctagonState*)errorState
{
if((self = [super init])) {
_nextState = errorState;
_intendedState = intendedState;
}
return self;
}

- (NSString*)description
{
return [NSString stringWithFormat:@"<OctagonStateTransitionGroupOperation(%@): intended:%@ actual:%@>", self.name, self.intendedState, self.nextState];
}

+ (instancetype)named:(NSString*)name
intending:(OctagonState*)intendedState
errorState:(OctagonState*)errorState
withBlockTakingSelf:(void(^)(OctagonStateTransitionGroupOperation* op))block
{
OctagonStateTransitionGroupOperation* op = [[self alloc] initIntending:intendedState
errorState:errorState];
WEAKIFY(op);
[op runBeforeGroupFinished:[NSBlockOperation blockOperationWithBlock:^{
STRONGIFY(op);
block(op);
}]];
op.name = name;
return op;
}
@end

#pragma mark -- OctagonStateTransitionRequest

@interface OctagonStateTransitionRequest ()
@property dispatch_queue_t queue;
@property bool timeoutCanOccur;
@end

@implementation OctagonStateTransitionRequest

- (instancetype)init:(NSString*)name
sourceStates:(NSSet<OctagonState*>*)sourceStates
serialQueue:(dispatch_queue_t)queue
timeout:(dispatch_time_t)timeout
transitionOp:(CKKSResultOperation<OctagonStateTransitionOperationProtocol>*)transitionOp
{
if((self = [super init])) {
_name = name;
_sourceStates = sourceStates;
_queue = queue;

_timeoutCanOccur = true;
_transitionOperation = transitionOp;
}

[self timeout:timeout];

return self;
}

- (NSString*)description
{
return [NSString stringWithFormat:@"<OctagonStateTransitionRequest: %@ %@ sources:%d>", self.name, self.transitionOperation, (unsigned int)[self.sourceStates count]];
}

- (CKKSResultOperation<OctagonStateTransitionOperationProtocol>* _Nullable)_onqueueStart
{
dispatch_assert_queue(self.queue);

if(self.timeoutCanOccur) {
self.timeoutCanOccur = false;
return self.transitionOperation;
} else {
return nil;
}
}

- (instancetype)timeout:(dispatch_time_t)timeout
{
WEAKIFY(self);
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, timeout), self.queue, ^{
STRONGIFY(self);
if(self.timeoutCanOccur) {
self.timeoutCanOccur = false;

// The operation will only realize it's finished once added to any operation queue. Fake one up.
[self.transitionOperation timeout:0*NSEC_PER_SEC];
[[[NSOperationQueue alloc] init] addOperation:self.transitionOperation];
}
});

return self;
}

@end

@implementation NSError (Octagon)

- (NSTimeInterval)overallCuttlefishRetry {
NSTimeInterval baseDelay = SecCKKSTestsEnabled() ? 2 : 30;
NSTimeInterval ckDelay = CKRetryAfterSecondsForError(self);
NSTimeInterval cuttlefishDelay = [self cuttlefishRetryAfter];
NSTimeInterval delay = MAX(ckDelay, cuttlefishDelay);
if (delay == 0) {
delay = baseDelay;
}
return delay;
}

- (bool)retryableCuttlefishError {
bool retry = false;
// Specific errors that are transaction failed -- try them again
if ([self isCuttlefishError:CuttlefishErrorRetryableServerFailure] ||
[self isCuttlefishError:CuttlefishErrorTransactionalFailure]) {
retry = true;
// These are the CuttlefishError -> FunctionErrorType
} else if ([self isCuttlefishError:CuttlefishErrorJoinFailed] ||
[self isCuttlefishError:CuttlefishErrorUpdateTrustFailed] ||
[self isCuttlefishError:CuttlefishErrorEstablishPeerFailed] ||
[self isCuttlefishError:CuttlefishErrorEstablishBottleFailed] ||
[self isCuttlefishError:CuttlefishErrorEscrowProxyFailure]) {
retry = true;
} else if ([self.domain isEqualToString:TrustedPeersHelperErrorDomain]) {
switch (self.code) {
case TrustedPeersHelperErrorUnknownCloudKitError:
retry = true;
break;
default:
break;
}
} else if ([self.domain isEqualToString:NSURLErrorDomain]) {
switch (self.code) {
case NSURLErrorTimedOut:
retry = true;
break;
default:
break;
}
} else if ([self.domain isEqualToString:CKErrorDomain]) {
if (self.userInfo[CKErrorRetryAfterKey] != nil) {
retry = true;
} else {
switch (self.code) {
case CKErrorNetworkFailure:
retry = true;
break;
default:
break;
}
}
} else if ([self isCKServerInternalError]) {
retry = true;
}

return retry;
}

@end

#endif // OCTAGON