perf: Improvements on retrieving frozenContacts (#1281)

MailCore/Cache/ContactManager/ContactManager+DB.swift

@@ -25,7 +25,7 @@ public protocol ContactFetchable {
     ///   - string: input string to match against email and name
     ///   - fetchLimit: limit the query by default to limit memory footprint
     /// - Returns: The collection of matching contacts.
-    func frozenContacts(matching string: String, fetchLimit: Int?) -> [MergedContact]
+    func frozenContacts(matching string: String, fetchLimit: Int?) -> any Collection<MergedContact>
     func getContact(for correspondent: any Correspondent, realm: Realm?) -> MergedContact?
     func addressBook(with id: Int) -> AddressBook?
     func addContact(recipient: Recipient) async throws
@@ -43,16 +43,17 @@ public extension ContactManager {
     ///   - string: input string to match against email and name
     ///   - fetchLimit: limit the query by default to limit memory footprint
     /// - Returns: The collection of matching contacts. Frozen.
-    func frozenContacts(matching string: String, fetchLimit: Int?) -> [MergedContact] {
+    func frozenContacts(matching string: String, fetchLimit: Int?) -> any Collection<MergedContact> {
         let realm = getRealm()
         let lazyResults = realm
             .objects(MergedContact.self)
             .filter(Self.searchContactInsensitivePredicate, string, string)
+            .freeze()
 
         let fetchLimit = min(lazyResults.count, fetchLimit ?? Self.contactFetchLimit)
 
         let limitedResults = lazyResults[0 ..< fetchLimit]
-        return limitedResults.map { $0.freezeIfNeeded() }
+        return limitedResults
     }
 
     func getContact(for correspondent: any Correspondent, realm: Realm? = nil) -> MergedContact? {

MailTests/Contacts/UTContactManager.swift

@@ -0,0 +1,57 @@
+/*
+ Infomaniak Mail - iOS App
+ Copyright (C) 2024 Infomaniak Network SA
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import MailCore
+import XCTest
+
+final class UTContactManager: XCTestCase {
+    let contactManager = ContactManager(userId: 0, apiFetcher: MailApiFetcher())
+
+    override func setUpWithError() throws {}
+
+    func generateFakeContacts(count: Int) {
+        let realm = contactManager.getRealm()
+        // swiftlint:disable:next force_try
+        try! realm.write {
+            realm.deleteAll()
+        }
+
+        // swiftlint:disable:next force_try
+        try! realm.write {
+            for i in 0 ..< count {
+                let contact = MergedContact()
+                contact.id = i
+                let randomName = UUID().uuidString
+                contact.name = "\(randomName)"
+                contact.email = "\(randomName)@somemail.com"
+                realm.add(contact)
+            }
+        }
+    }
+
+    func testGetContactsMatching() throws {
+        // GIVEN
+        generateFakeContacts(count: 100_000)
+        measure {
+            // WHEN
+            let matchingContacts = contactManager.frozenContacts(matching: "mail", fetchLimit: nil)
+            // THEN
+            XCTAssertEqual(matchingContacts.isEmpty, false)
+        }
+    }
+}

MailTests/Folders/ITFolderListViewModel.swift

@@ -26,7 +26,7 @@ import InfomaniakLogin
 import XCTest
 
 struct MCKContactManageable_FolderListViewModel: ContactManageable {
-    func frozenContacts(matching string: String, fetchLimit: Int?) -> [MailCore.MergedContact] { [] }
+    func frozenContacts(matching string: String, fetchLimit: Int?) -> any Collection<MailCore.MergedContact> { [] }
 
     func getContact(for correspondent: any MailCore.Correspondent, realm: RealmSwift.Realm?) -> MailCore.MergedContact? { nil }
 

MailTests/Search/ITSearchViewModel.swift

@@ -28,7 +28,7 @@ import XCTest
 
 /// A ContactManageable used to test the SearchViewModel
 struct MCKContactManageable_SearchViewModel: ContactManageable {
-    func frozenContacts(matching string: String, fetchLimit: Int?) -> [MailCore.MergedContact] { [] }
+    func frozenContacts(matching string: String, fetchLimit: Int?) -> any Collection<MailCore.MergedContact> { [] }
 
     func getContact(for correspondent: any MailCore.Correspondent, realm: RealmSwift.Realm?) -> MailCore.MergedContact? { nil }