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Remove one of the caches from DatabaseLookupTable.

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This commit is contained in:
Brent Simmons 2017-08-14 13:16:52 -07:00
parent fec53ba309
commit 177667d639
1 changed files with 28 additions and 62 deletions
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90
Frameworks/RSDatabase/RSDatabase/DatabaseLookupTable.swift
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@ -20,7 +20,6 @@ public final class DatabaseLookupTable {
private let relationshipName: String
private weak var relatedTable: DatabaseTable?
private var foreignIDsWithNoRelationship = Set<String>()
private var cache = LookupTable(Set<LookupValue>())
public init(name: String, primaryKey: String, foreignKey: String, relatedTable: DatabaseTable, relationshipName: String) {
@ -81,50 +80,29 @@ private extension DatabaseLookupTable {
func fetchLookupTable(_ foreignIDs: Set<String>, _ database: FMDatabase) -> LookupTable? {
let foreignIDsToLookup = foreignIDs.subtracting(foreignIDsWithNoRelationship)
if foreignIDsToLookup.isEmpty {
guard !foreignIDsToLookup.isEmpty, let lookupValues = fetchLookupValues(foreignIDsToLookup, database) else {
return nil
}
var lookupValues = Set<LookupValue>()
var foreignIDsToFetchFromDatabase = Set<String>()
// Pull from cache.
for foreignID in foreignIDsToLookup {
if let cachedLookups = cache[foreignID] {
lookupValues.formUnion(cachedLookups)
}
else {
foreignIDsToFetchFromDatabase.insert(foreignID)
}
}
// Fetch from database.
let fetchedLookupValues = fetchLookupValues(foreignIDsToFetchFromDatabase, database)
if let fetchedLookupValues = fetchedLookupValues {
lookupValues.formUnion(fetchedLookupValues)
cache.addLookupValues(fetchedLookupValues)
}
// Maintain cache.
cacheNotFoundForeignIDs(lookupValues, foreignIDsToFetchFromDatabase)
updateCache(lookupValues, foreignIDsToLookup)
return LookupTable(lookupValues)
}
func cacheNotFoundForeignIDs(_ lookupValues: Set<LookupValue>, _ foreignIDs: Set<String>) {
func updateCache(_ lookupValues: Set<LookupValue>, _ foreignIDs: Set<String>) {
// Note where nothing was found, and cache the foreignID in foreignIDsWithNoRelationship.
// Maintain foreignIDsWithNoRelationship.
// If a relationship exist, remove the foreignID from foreignIDsWithNoRelationship.
// If a relationship does not exist, add the foreignID to foreignIDsWithNoRelationship.
let foreignIDsWithRelationship = lookupValues.foreignIDs()
foreignIDsWithNoRelationship.subtract(foreignIDsWithRelationship)
let foundForeignIDs = lookupValues.foreignIDs()
var foreignIDsToRemove = Set<String>()
for foreignID in foreignIDs {
if !foundForeignIDs.contains(foreignID) {
if !foreignIDsWithRelationship.contains(foreignID) {
foreignIDsWithNoRelationship.insert(foreignID)
foreignIDsToRemove.insert(foreignID)
}
}
cache.removeLookupValuesForForeignIDs(foreignIDsToRemove)
}
func removeLookupsForForeignIDs(_ foreignIDs: Set<String>, _ database: FMDatabase) {
@ -134,7 +112,6 @@ private extension DatabaseLookupTable {
return
}
cache.removeLookupValuesForForeignIDs(foreignIDsToRemove)
foreignIDsWithNoRelationship.formUnion(foreignIDsToRemove)
database.rs_deleteRowsWhereKey(foreignKey, inValues: Array(foreignIDsToRemove), tableName: name)
@ -166,15 +143,27 @@ private extension DatabaseLookupTable {
}
private class LookupTable {
struct LookupTable {
var dictionary = [String: Set<LookupValue>]()
private let dictionary: [String: Set<LookupValue>]
init(_ lookupValues: Set<LookupValue>) {
addLookupValues(lookupValues)
var d = [String: Set<LookupValue>]()
for lookupValue in lookupValues {
let foreignID = lookupValue.foreignID
if d[foreignID] == nil {
d[foreignID] = Set([lookupValue])
}
else {
d[foreignID]!.insert(lookupValue)
}
}
self.dictionary = d
}
func primaryIDs() -> Set<String> {
var ids = Set<String>()
@ -184,37 +173,14 @@ private class LookupTable {
return ids
}
func addLookupValues(_ values: Set<LookupValue>) {
for lookupValue in values {
let foreignID = lookupValue.foreignID
if self[foreignID] == nil {
self[foreignID] = Set([lookupValue])
}
else {
self[foreignID]!.insert(lookupValue)
}
}
}
func removeLookupValuesForForeignIDs(_ foreignIDs: Set<String>) {
for foreignID in foreignIDs {
self[foreignID] = nil
}
}
subscript(_ foreignID: String) -> Set<LookupValue>? {
get {
return dictionary[foreignID]
}
set {
dictionary[foreignID] = newValue
}
}
}
private struct LookupValue: Hashable {
struct LookupValue: Hashable {
let primaryID: String
let foreignID: String