Files
CoreStore/Sources/SynchronousDataTransaction.swift
2018-09-15 12:56:08 +09:00

243 lines
9.2 KiB
Swift

//
// SynchronousDataTransaction.swift
// CoreStore
//
// Copyright © 2018 John Rommel Estropia
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//
import Foundation
import CoreData
// MARK: - SynchronousDataTransaction
/**
The `SynchronousDataTransaction` provides an interface for `DynamicObject` creates, updates, and deletes. A transaction object should typically be only used from within a transaction block initiated from `DataStack.beginSynchronous(_:)`, or from `CoreStore.beginSynchronous(_:)`.
*/
public final class SynchronousDataTransaction: BaseDataTransaction {
/**
Cancels a transaction by throwing `CoreStoreError.userCancelled`.
```
try transaction.cancel()
```
- Important: Always use plain `try` on a `cancel()` call. Never use `try?` or `try!`. Using `try?` will swallow the cancellation and the transaction will proceed to commit as normal. Using `try!` will crash the app as `cancel()` will *always* throw an error.
*/
public func cancel() throws -> Never {
throw CoreStoreError.userCancelled
}
// MARK: BaseDataTransaction
/**
Creates a new `NSManagedObject` or `CoreStoreObject` with the specified entity type.
- parameter into: the `Into` clause indicating the destination `NSManagedObject` or `CoreStoreObject` entity type and the destination configuration
- returns: a new `NSManagedObject` or `CoreStoreObject` instance of the specified entity type.
*/
public override func create<D>(_ into: Into<D>) -> D {
CoreStore.assert(
!self.isCommitted,
"Attempted to create an entity of type \(cs_typeName(into.entityClass)) from an already committed \(cs_typeName(self))."
)
return super.create(into)
}
/**
Returns an editable proxy of a specified `NSManagedObject` or `CoreStoreObject`.
- parameter object: the `NSManagedObject` or `CoreStoreObject` to be edited
- returns: an editable proxy for the specified `NSManagedObject` or `CoreStoreObject`.
*/
public override func edit<D: DynamicObject>(_ object: D?) -> D? {
CoreStore.assert(
!self.isCommitted,
"Attempted to update an entity of type \(cs_typeName(object)) from an already committed \(cs_typeName(self))."
)
return super.edit(object)
}
/**
Returns an editable proxy of the object with the specified `NSManagedObjectID`.
- parameter into: an `Into` clause specifying the entity type
- parameter objectID: the `NSManagedObjectID` for the object to be edited
- returns: an editable proxy for the specified `NSManagedObject` or `CoreStoreObject`.
*/
public override func edit<D>(_ into: Into<D>, _ objectID: NSManagedObjectID) -> D? {
CoreStore.assert(
!self.isCommitted,
"Attempted to update an entity of type \(cs_typeName(into.entityClass)) from an already committed \(cs_typeName(self))."
)
return super.edit(into, objectID)
}
/**
Deletes a specified `NSManagedObject` or `CoreStoreObject`.
- parameter object: the `NSManagedObject` or `CoreStoreObject` type to be deleted
*/
public override func delete<D: DynamicObject>(_ object: D?) {
CoreStore.assert(
!self.isCommitted,
"Attempted to delete an entity of type \(cs_typeName(object)) from an already committed \(cs_typeName(self))."
)
super.delete(object)
}
/**
Deletes the specified `DynamicObject`s.
- parameter object1: the `DynamicObject` to be deleted
- parameter object2: another `DynamicObject` to be deleted
- parameter objects: other `DynamicObject`s to be deleted
*/
public override func delete<D: DynamicObject>(_ object1: D?, _ object2: D?, _ objects: D?...) {
CoreStore.assert(
!self.isCommitted,
"Attempted to delete an entities from an already committed \(cs_typeName(self))."
)
super.delete(([object1, object2] + objects).compactMap { $0 })
}
/**
Deletes the specified `DynamicObject`s.
- parameter objects: the `DynamicObject`s to be deleted
*/
public override func delete<S: Sequence>(_ objects: S) where S.Iterator.Element: DynamicObject {
CoreStore.assert(
!self.isCommitted,
"Attempted to delete an entities from an already committed \(cs_typeName(self))."
)
super.delete(objects)
}
// MARK: Internal
internal init(mainContext: NSManagedObjectContext, queue: DispatchQueue) {
super.init(mainContext: mainContext, queue: queue, supportsUndo: false, bypassesQueueing: false)
}
internal func autoCommit(waitForMerge: Bool) -> (hasChanges: Bool, error: CoreStoreError?) {
self.isCommitted = true
let result = self.context.saveSynchronously(waitForMerge: waitForMerge)
self.result = result
defer {
self.context.reset()
}
return result
}
// MARK: Deprecated
@available(*, deprecated, message: "Use the new auto-commit method DataStack.perform(synchronous:waitForAllObservers:)")
public func commitAndWait() -> SaveResult {
CoreStore.assert(
self.transactionQueue.cs_isCurrentExecutionContext(),
"Attempted to commit a \(cs_typeName(self)) outside its designated queue."
)
CoreStore.assert(
!self.isCommitted,
"Attempted to commit a \(cs_typeName(self)) more than once."
)
switch self.autoCommit(waitForMerge: true) {
case (let hasChanges, nil): return SaveResult(hasChanges: hasChanges)
case (_, let error?): return SaveResult(error)
}
}
@available(*, deprecated, message: "Use the new auto-commit method DataStack.perform(synchronous:waitForAllObservers:)")
public func commit() -> SaveResult {
CoreStore.assert(
self.transactionQueue.cs_isCurrentExecutionContext(),
"Attempted to commit a \(cs_typeName(self)) outside its designated queue."
)
CoreStore.assert(
!self.isCommitted,
"Attempted to commit a \(cs_typeName(self)) more than once."
)
switch self.autoCommit(waitForMerge: false) {
case (let hasChanges, nil): return SaveResult(hasChanges: hasChanges)
case (_, let error?): return SaveResult(error)
}
}
@available(*, deprecated, message: "Secondary tasks spawned from AsynchronousDataTransactions and SynchronousDataTransactions are no longer supported. ")
@discardableResult
public func beginSynchronous(_ closure: @escaping (_ transaction: SynchronousDataTransaction) -> Void) -> SaveResult? {
CoreStore.assert(
self.transactionQueue.cs_isCurrentExecutionContext(),
"Attempted to begin a child transaction from a \(cs_typeName(self)) outside its designated queue."
)
CoreStore.assert(
!self.isCommitted,
"Attempted to begin a child transaction from an already committed \(cs_typeName(self))."
)
let childTransaction = SynchronousDataTransaction(
mainContext: self.context,
queue: self.childTransactionQueue
)
childTransaction.transactionQueue.cs_sync {
closure(childTransaction)
if !childTransaction.isCommitted && childTransaction.hasChanges {
CoreStore.log(
.warning,
message: "The closure for the \(cs_typeName(childTransaction)) completed without being committed. All changes made within the transaction were discarded."
)
}
}
switch childTransaction.result {
case .none: return nil
case .some(let hasChanges, nil): return SaveResult(hasChanges: hasChanges)
case .some(_, let error?): return SaveResult(error)
}
}
}