Files
CoreStore/Sources/SchemaHistory.swift
2024-09-10 11:14:39 +09:00

233 lines
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Swift

//
// SchemaHistory.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 CoreData
import Foundation
// MARK: - SchemaHistory
/**
The `SchemaHistory` encapsulates multiple `DynamicSchema` across multiple model versions. It contains all model history and is used by the `DataStack` to
*/
public final class SchemaHistory: ExpressibleByArrayLiteral {
/**
The version string for the current model version. The `DataStack` will try to migrate all `StorageInterface`s added to itself to this version, following the version steps provided by the `migrationChain`.
*/
public let currentModelVersion: ModelVersion
/**
The schema for the current model version. The `DataStack` will try to migrate all `StorageInterface`s added to itself to this version, following the version steps provided by the `migrationChain`.
*/
public var currentSchema: DynamicSchema {
return self.schema(for: self.currentModelVersion)!
}
/**
The version string for the current model version. The `DataStack` will try to migrate all `StorageInterface`s added to itself to this version, following the version steps provided by the `migrationChain`.
*/
public let migrationChain: MigrationChain
/**
Convenience initializer for a `SchemaHistory` created from a single xcdatamodeld file.
- parameter xcodeDataModeld: a tuple returned from the `XcodeDataModelSchema.from(modelName:bundle:migrationChain:)` method.
- parameter migrationChain: the `MigrationChain` that indicates the sequence of model versions to be used as the order for progressive migrations. If not specified, will default to a non-migrating data stack.
*/
public convenience init(
_ xcodeDataModeld: (
allSchema: [XcodeDataModelSchema],
currentModelVersion: ModelVersion
),
migrationChain: MigrationChain = nil
) {
self.init(
allSchema: xcodeDataModeld.allSchema,
migrationChain: migrationChain,
exactCurrentModelVersion: xcodeDataModeld.currentModelVersion
)
}
/**
Initializes a `SchemaHistory` with a list of `DynamicSchema` and a `MigrationChain` to describe the order of progressive migrations.
- parameter schema: a `DynamicSchema` that represents a model version
- parameter otherSchema: a list of `DynamicSchema` that represent other model versions
- parameter migrationChain: the `MigrationChain` that indicates the sequence of model versions to be used as the order for progressive migrations. If not specified, will default to a non-migrating data stack.
- parameter exactCurrentModelVersion: an optional string to explicitly select the current model version string. This is useful if the `DataStack` should load a non-latest model version (usually to prepare data before migration). If not provided, the current model version will be computed from the `MigrationChain`.
*/
public convenience init(
_ schema: DynamicSchema,
_ otherSchema: DynamicSchema...,
migrationChain: MigrationChain = nil,
exactCurrentModelVersion: String? = nil
) {
self.init(
allSchema: [schema] + otherSchema,
migrationChain: migrationChain,
exactCurrentModelVersion: exactCurrentModelVersion
)
}
/**
Initializes a `SchemaHistory` with a list of `DynamicSchema` and a `MigrationChain` to describe the order of progressive migrations.
- parameter allSchema: a list of `DynamicSchema` that represent model versions
- parameter migrationChain: the `MigrationChain` that indicates the sequence of model versions to be used as the order for progressive migrations. If not specified, will default to a non-migrating data stack.
- parameter exactCurrentModelVersion: an optional string to explicitly select the current model version string. This is useful if the `DataStack` should load a non-latest model version (usually to prepare data before migration). If not provided, the current model version will be computed from the `MigrationChain`.
*/
public required init(
allSchema: [DynamicSchema],
migrationChain: MigrationChain = nil,
exactCurrentModelVersion: String? = nil
) {
if allSchema.isEmpty {
Internals.abort("The \"allSchema\" argument of the \(Internals.typeName(SchemaHistory.self)) initializer cannot be empty.")
}
Internals.assert(
migrationChain.isValid,
"Invalid migration chain passed to the \(Internals.typeName(SchemaHistory.self)). Check that the model versions' order are correct and that no repetitions or ambiguities exist."
)
var schemaByVersion: [ModelVersion: DynamicSchema] = [:]
for schema in allSchema {
let modelVersion = schema.modelVersion
Internals.assert(
schemaByVersion[modelVersion] == nil,
"Multiple model schema found for model version \"\(modelVersion)\"."
)
schemaByVersion[modelVersion] = schema
}
let modelVersions = Set(schemaByVersion.keys)
let currentModelVersion: ModelVersion
if let exactCurrentModelVersion = exactCurrentModelVersion {
if !migrationChain.isEmpty && !migrationChain.contains(exactCurrentModelVersion) {
Internals.abort("An \"exactCurrentModelVersion\" argument was provided to \(Internals.typeName(SchemaHistory.self)) initializer but a matching schema could not be found from the provided \(Internals.typeName(MigrationChain.self)).")
}
if schemaByVersion[exactCurrentModelVersion] == nil {
Internals.abort("An \"exactCurrentModelVersion\" argument was provided to \(Internals.typeName(SchemaHistory.self)) initializer but a matching schema could not be found from the \(Internals.typeName(DynamicSchema.self)) list.")
}
currentModelVersion = exactCurrentModelVersion
}
else if migrationChain.isEmpty && schemaByVersion.count == 1 {
currentModelVersion = schemaByVersion.keys.first!
}
else {
let candidateVersions = modelVersions.intersection(migrationChain.leafVersions)
switch candidateVersions.count {
case 0:
Internals.abort("None of the \(Internals.typeName(MigrationChain.self)) leaf versions provided to the \(Internals.typeName(SchemaHistory.self)) initializer matches any scheme from the \(Internals.typeName(DynamicSchema.self)) list.")
case 1:
currentModelVersion = candidateVersions.first!
default:
Internals.abort("Could not resolve the \(Internals.typeName(SchemaHistory.self)) current model version because the \(Internals.typeName(MigrationChain.self)) have ambiguous leaf versions: \(candidateVersions)")
}
}
self.schemaByVersion = schemaByVersion
self.migrationChain = migrationChain
self.currentModelVersion = currentModelVersion
self.rawModel = schemaByVersion[currentModelVersion]!.rawModel()
}
// MARK: ExpressibleByArrayLiteral
public typealias Element = DynamicSchema
public convenience init(arrayLiteral elements: DynamicSchema...) {
self.init(
allSchema: elements,
migrationChain: MigrationChain(elements.map({ $0.modelVersion })),
exactCurrentModelVersion: nil
)
}
// MARK: Internal
internal let schemaByVersion: [ModelVersion: DynamicSchema]
internal let rawModel: NSManagedObjectModel
internal private(set) lazy var entityDescriptionsByEntityIdentifier: [Internals.EntityIdentifier: NSEntityDescription] = Internals.with { [unowned self] in
var mapping: [Internals.EntityIdentifier: NSEntityDescription] = [:]
self.rawModel.entities.forEach { (entityDescription) in
let entityIdentifier = Internals.EntityIdentifier(entityDescription)
mapping[entityIdentifier] = entityDescription
}
return mapping
}
internal func rawModel(for modelVersion: ModelVersion) -> NSManagedObjectModel? {
if modelVersion == self.currentModelVersion {
return self.rawModel
}
return self.schemaByVersion[modelVersion]?.rawModel()
}
internal func schema(for modelVersion: ModelVersion) -> DynamicSchema? {
return self.schemaByVersion[modelVersion]
}
internal func schema(for storeMetadata: [String: Any]) -> DynamicSchema? {
guard let modelHashes = storeMetadata[NSStoreModelVersionHashesKey] as! [String: Data]? else {
return nil
}
for (_, schema) in self.schemaByVersion {
let rawModel = schema.rawModel()
if modelHashes == rawModel.entityVersionHashesByName {
return schema
}
}
return nil
}
internal func mergedModels() -> [NSManagedObjectModel] {
return self.schemaByVersion.values.map({ $0.rawModel() })
}
}