Move RelayCache.IO and CachedRelays into new RelayCache.framework

Moved RelayCache.IO and CachedRelays into new RelayCache.framework

Moved prebuild script to build phase script.

Renamed script, renamed/moved RelayCache.IO to RelayCache.

Renamed RelayCache.Tracker to RelayCacheTracker.

Set APPLICATION_EXTENSION_API_ONLY to true for RelayCache framework.

Updated gitignore.

Removed relays.json from git.

Removed relays.json from RelayCache framework

Removed RelayCache/FetchResult, moved/renamed code into RelayCacheTracker file.

Renamed CachedRelaysFetchResult to RelaysFetchResult.

Changed access level for RelaysFetchResult and NoCachedRelaysError.

3 files changed, 157 insertions, 0 deletions

diff --git a/ios/RelayCache/CachedRelays.swift b/ios/RelayCache/CachedRelays.swift
new file mode 100644
index 0000000000..6ff9c36091
--- /dev/null
+++ b/ios/RelayCache/CachedRelays.swift
@@ -0,0 +1,28 @@
+//
+//  CachedRelays.swift
+//  CachedRelays
+//
+//  Created by pronebird on 27/07/2021.
+//  Copyright © 2021 Mullvad VPN AB. All rights reserved.
+//
+
+import Foundation
+import MullvadREST
+
+/// A struct that represents the relay cache on disk
+public struct CachedRelays: Codable {
+    /// E-tag returned by server
+    public var etag: String?
+
+    /// The relay list stored within the cache entry
+    public var relays: REST.ServerRelaysResponse
+
+    /// The date when this cache was last updated
+    public var updatedAt: Date
+
+    public init(etag: String? = nil, relays: REST.ServerRelaysResponse, updatedAt: Date) {
+        self.etag = etag
+        self.relays = relays
+        self.updatedAt = updatedAt
+    }
+}
diff --git a/ios/RelayCache/RelayCache.h b/ios/RelayCache/RelayCache.h
new file mode 100644
index 0000000000..abe3d1b983
--- /dev/null
+++ b/ios/RelayCache/RelayCache.h
@@ -0,0 +1,19 @@
+//
+//  RelayCache.h
+//  RelayCache
+//
+//  Created by Sajad Vishkai on 2022-10-21.
+//  Copyright © 2022 Mullvad VPN AB. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+//! Project version number for RelayCache.
+FOUNDATION_EXPORT double RelayCacheVersionNumber;
+
+//! Project version string for RelayCache.
+FOUNDATION_EXPORT const unsigned char RelayCacheVersionString[];
+
+// In this header, you should import all the public headers of your framework using statements like #import <RelayCache/PublicHeader.h>
+
+
diff --git a/ios/RelayCache/RelayCache.swift b/ios/RelayCache/RelayCache.swift
new file mode 100644
index 0000000000..64ce748128
--- /dev/null
+++ b/ios/RelayCache/RelayCache.swift
@@ -0,0 +1,110 @@
+//
+//  RelayCache.swift
+//  RelayCache
+//
+//  Created by pronebird on 06/09/2021.
+//  Copyright © 2021 Mullvad VPN AB. All rights reserved.
+//
+
+import Foundation
+import MullvadREST
+
+public class RelayCache {
+    /// The default cache file location bound by app group container.
+    public static func defaultCacheFileURL(
+        forSecurityApplicationGroupIdentifier appGroupIdentifier: String
+    ) -> URL? {
+        let containerURL = FileManager.default.containerURL(
+            forSecurityApplicationGroupIdentifier: appGroupIdentifier
+        )
+
+        return containerURL?.appendingPathComponent("relays.json")
+    }
+
+    /// The path to pre-bundled `relays.json` file.
+    public static var preBundledRelaysFileURL: URL? {
+        return Bundle(for: Self.self).url(forResource: "relays", withExtension: "json")
+    }
+
+    /// Safely read the cache file from disk using file coordinator.
+    public static func read(cacheFileURL: URL) throws -> CachedRelays {
+        var result: Result<CachedRelays, Error>?
+        let fileCoordinator = NSFileCoordinator(filePresenter: nil)
+
+        let accessor = { (fileURLForReading: URL) in
+            result = Result {
+                let data = try Data(contentsOf: fileURLForReading)
+                return try JSONDecoder().decode(CachedRelays.self, from: data)
+            }
+        }
+
+        var error: NSError?
+        fileCoordinator.coordinate(
+            readingItemAt: cacheFileURL,
+            options: [.withoutChanges],
+            error: &error,
+            byAccessor: accessor
+        )
+
+        if let error = error {
+            result = .failure(error)
+        }
+
+        return try result!.get()
+    }
+
+    /// Safely read the cache file from disk using file coordinator and fallback to prebundled
+    /// relays in case if the relay cache file is missing.
+    public static func readWithFallback(cacheFileURL: URL, preBundledRelaysFileURL: URL)
+        throws -> CachedRelays
+    {
+        do {
+            return try Self.read(cacheFileURL: cacheFileURL)
+        } catch {
+            if error is DecodingError || (error as? CocoaError)?.code == .fileReadNoSuchFile {
+                return try Self.readPrebundledRelays(fileURL: preBundledRelaysFileURL)
+            } else {
+                throw error
+            }
+        }
+    }
+
+    /// Read pre-bundled relays file from disk.
+    public static func readPrebundledRelays(fileURL: URL) throws -> CachedRelays {
+        let data = try Data(contentsOf: fileURL)
+        let relays = try REST.Coding.makeJSONDecoder()
+            .decode(REST.ServerRelaysResponse.self, from: data)
+
+        return CachedRelays(
+            relays: relays,
+            updatedAt: Date(timeIntervalSince1970: 0)
+        )
+    }
+
+    /// Safely write the cache file on disk using file coordinator.
+    public static func write(cacheFileURL: URL, record: CachedRelays) throws {
+        var result: Result<Void, Error>?
+        let fileCoordinator = NSFileCoordinator(filePresenter: nil)
+
+        let accessor = { (fileURLForWriting: URL) in
+            result = Result {
+                let data = try JSONEncoder().encode(record)
+                try data.write(to: fileURLForWriting)
+            }
+        }
+
+        var error: NSError?
+        fileCoordinator.coordinate(
+            writingItemAt: cacheFileURL,
+            options: [.forReplacing],
+            error: &error,
+            byAccessor: accessor
+        )
+
+        if let error = error {
+            result = .failure(error)
+        }
+
+        try result?.get()
+    }
+}