Fix API breaking down when used without connectivity

3 files changed, 76 insertions, 6 deletions

diff --git a/ios/MullvadRustRuntime/MullvadAddressCacheProvider.swift b/ios/MullvadRustRuntime/MullvadAddressCacheProvider.swift
new file mode 100644
index 0000000000..4c731eaf3a
--- /dev/null
+++ b/ios/MullvadRustRuntime/MullvadAddressCacheProvider.swift
@@ -0,0 +1,31 @@
+//
+//  MullvadAddressCacheProvider.swift
+//  MullvadRustRuntime
+//
+//  Created by Marco Nikic on 2025-05-15.
+//  Copyright © 2025 Mullvad VPN AB. All rights reserved.
+//
+
+import Foundation
+import MullvadTypes
+
+public func iniSwiftAddressCacheWrapper(provider: DefaultAddressCacheProvider) -> SwiftAddressCacheWrapper {
+    let rawProvider = Unmanaged.passUnretained(provider).toOpaque()
+    return init_swift_address_cache_wrapper(rawProvider)
+}
+
+@_cdecl("swift_get_cached_endpoint")
+func getCacheEndpoint(rawAddressCacheProvider: UnsafeMutableRawPointer) -> UnsafePointer<CChar>! {
+    let addressCacheProvider = Unmanaged<DefaultAddressCacheProvider>.fromOpaque(rawAddressCacheProvider)
+        .takeUnretainedValue()
+    let cStr = addressCacheProvider.getCurrentEndpoint().description.toCStringPointer()
+    /**
+     `cStr` needs to shortly outlive the return of this function in order to get transformed into a `SocketAddr`
+     This is the simplest way to guarantee that the pointer returned does not get deallocated immediately
+     Or that no memory is leaked every time this function gets called
+     **/
+    DispatchQueue(label: "com.MullvadRustRuntime.DecallocateQueue").async {
+        cStr?.deallocate()
+    }
+    return cStr
+}
diff --git a/ios/MullvadRustRuntime/MullvadApiContext.swift b/ios/MullvadRustRuntime/MullvadApiContext.swift
index 5517348cc1..bd89ab891f 100644
--- a/ios/MullvadRustRuntime/MullvadApiContext.swift
+++ b/ios/MullvadRustRuntime/MullvadApiContext.swift
@@ -16,6 +16,8 @@ public struct MullvadApiContext: @unchecked Sendable {
     public let context: SwiftApiContext
     private let shadowsocksBridgeProvider: SwiftShadowsocksBridgeProviding!
     private let shadowsocksBridgeProviderWrapper: SwiftShadowsocksLoaderWrapper!
+    private let addressCacheWrapper: SwiftAddressCacheWrapper!
+    private let addressCacheProvider: AddressCacheProviding!
 
     public init(
         host: String,
@@ -23,12 +25,17 @@ public struct MullvadApiContext: @unchecked Sendable {
         domain: String,
         disableTls: Bool = false,
         shadowsocksProvider: SwiftShadowsocksBridgeProviding,
-        accessMethodWrapper: SwiftAccessMethodSettingsWrapper
+        accessMethodWrapper: SwiftAccessMethodSettingsWrapper,
+        addressCacheProvider: AddressCacheProviding
     ) throws {
         let bridgeProvider = SwiftShadowsocksBridgeProvider(provider: shadowsocksProvider)
         self.shadowsocksBridgeProvider = bridgeProvider
         self.shadowsocksBridgeProviderWrapper = initMullvadShadowsocksBridgeProvider(provider: bridgeProvider)
 
+        let defaultAddressCache = DefaultAddressCacheProvider(provider: addressCacheProvider)
+        self.addressCacheProvider = defaultAddressCache
+        self.addressCacheWrapper = iniSwiftAddressCacheWrapper(provider: defaultAddressCache)
+
         context = switch disableTls {
         case true:
             mullvad_api_init_new_tls_disabled(
@@ -36,7 +43,8 @@ public struct MullvadApiContext: @unchecked Sendable {
                 address,
                 domain,
                 shadowsocksBridgeProviderWrapper,
-                accessMethodWrapper
+                accessMethodWrapper,
+                addressCacheWrapper
             )
         case false:
             mullvad_api_init_new(
@@ -44,7 +52,8 @@ public struct MullvadApiContext: @unchecked Sendable {
                 address,
                 domain,
                 shadowsocksBridgeProviderWrapper,
-                accessMethodWrapper
+                accessMethodWrapper,
+                addressCacheWrapper
             )
         }
 
diff --git a/ios/MullvadRustRuntime/include/mullvad_rust_runtime.h b/ios/MullvadRustRuntime/include/mullvad_rust_runtime.h
index accd302d53..70c1428098 100644
--- a/ios/MullvadRustRuntime/include/mullvad_rust_runtime.h
+++ b/ios/MullvadRustRuntime/include/mullvad_rust_runtime.h
@@ -61,6 +61,14 @@ typedef struct SwiftShadowsocksLoaderWrapper {
   struct SwiftShadowsocksLoaderWrapperContext _0;
 } SwiftShadowsocksLoaderWrapper;
 
+typedef struct SwiftAddressCacheProviderContext {
+  const void *address_cache;
+} SwiftAddressCacheProviderContext;
+
+typedef struct SwiftAddressCacheWrapper {
+  struct SwiftAddressCacheProviderContext _0;
+} SwiftAddressCacheWrapper;
+
 typedef struct SwiftCancelHandle {
   struct RequestCancelHandle *ptr;
 } SwiftCancelHandle;
@@ -161,7 +169,8 @@ struct SwiftApiContext mullvad_api_init_new_tls_disabled(const char *host,
                                                          const char *address,
                                                          const char *domain,
                                                          struct SwiftShadowsocksLoaderWrapper bridge_provider,
-                                                         struct SwiftAccessMethodSettingsWrapper settings_provider);
+                                                         struct SwiftAccessMethodSettingsWrapper settings_provider,
+                                                         struct SwiftAddressCacheWrapper address_cache);
 
 /**
  * # Safety
@@ -181,7 +190,8 @@ struct SwiftApiContext mullvad_api_init_new(const char *host,
                                             const char *address,
                                             const char *domain,
                                             struct SwiftShadowsocksLoaderWrapper bridge_provider,
-                                            struct SwiftAccessMethodSettingsWrapper settings_provider);
+                                            struct SwiftAccessMethodSettingsWrapper settings_provider,
+                                            struct SwiftAddressCacheWrapper address_cache);
 
 /**
  * # Safety
@@ -202,7 +212,8 @@ struct SwiftApiContext mullvad_api_init_inner(const char *host,
                                               const char *domain,
                                               bool disable_tls,
                                               struct SwiftShadowsocksLoaderWrapper bridge_provider,
-                                              struct SwiftAccessMethodSettingsWrapper settings_provider);
+                                              struct SwiftAccessMethodSettingsWrapper settings_provider,
+                                              struct SwiftAddressCacheWrapper address_cache);
 
 /**
  * Converts parameters into a `Box<AccessMethodSetting>` raw representation that
@@ -299,6 +310,25 @@ struct SwiftCancelHandle mullvad_ios_delete_account(struct SwiftApiContext api_c
                                                     const char *account_number);
 
 /**
+ * Return the latest available endpoint, or a default one if none are cached
+ *
+ * # SAFETY
+ * `rawAddressCacheProvider` **must** be provided by a call to `init_swift_address_cache_wrapper`
+ * It is okay to persist it, and use it accross multiple threads.
+ */
+extern const char *swift_get_cached_endpoint(const void *rawAddressCacheProvider);
+
+/**
+ * Called by the Swift side in order to provide an object to rust that provides API addresses in a UTF-8 string form
+ *
+ * # SAFETY
+ * `address_cache` **must be** pointing to a valid instance of a `DefaultAddressCacheProvider`
+ * That instance's lifetime has to be equivalent to a `'static` lifetime in Rust
+ * This function does not take ownership of `address_cache`
+ */
+struct SwiftAddressCacheWrapper init_swift_address_cache_wrapper(const void *address_cache);
+
+/**
  * # Safety
  *
  * `api_context` must be pointing to a valid instance of `SwiftApiContext`. A `SwiftApiContext` is created