Security-59306.11.20.tar.gz

[apple/security.git] / keychain / ot / OctagonStateMachineHelpers.m

diff --git a/keychain/ot/OctagonStateMachineHelpers.m b/keychain/ot/OctagonStateMachineHelpers.m
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+/*
+ * 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"
+
+OctagonState* const OctagonStateMachineNotStarted = (OctagonState*) @"not_started";
+OctagonState* const OctagonStateMachineHalted = (OctagonState*) @"halted";
+
+@implementation OctagonStateTransitionOperation : CKKSResultOperation
+- (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
+              timeout:(dispatch_time_t)timeout
+  withBlockTakingSelf:(void(^)(OctagonStateTransitionOperation* op))block
+{
+    OctagonStateTransitionOperation* op = [[self alloc] initIntending:intendedState
+                                                           errorState:errorState];
+    WEAKIFY(op);
+    [op addExecutionBlock:^{
+        STRONGIFY(op);
+        block(op);
+    }];
+    op.name = name;
+    [op timeout:timeout];
+    return op;
+}
+
++ (instancetype)named:(NSString*)name
+             entering:(OctagonState*)intendedState
+{
+    OctagonStateTransitionOperation* op = [[self alloc] initIntending:intendedState
+                                                           errorState:intendedState];
+    op.name = name;
+    return op;
+}
+@end
+
+@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: %@ %@ %@>", self.name, self.transitionOperation, self.sourceStates];
+}
+
+- (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
+
+#endif // OCTAGON