iOS to use NSURLSessionDownloadTask in background. (#1457)

This allows to continue data downloading when in background. Ongoing
internal tasks are canceled. Timeouts should be set keeping in mind
this mechanism is quite slow.

Relates-To: OLPEDGE-2849

Signed-off-by: Rustam Gamidov <ext-rustam.gamidov@here.com>

Author: rustam-gamidov-here

CMakeLists.txt

@@ -45,6 +45,7 @@ option(OLP_SDK_DISABLE_DEBUG_LOGGING "Disable debug and trace level logging" OFF
 option(OLP_SDK_ENABLE_DEFAULT_CACHE "Enable default cache implementation based on LevelDB" ON)
 option(OLP_SDK_ENABLE_DEFAULT_CACHE_LMDB "Enable default cache implementation based on LMDB" OFF)
 option(OLP_SDK_ENABLE_ANDROID_CURL "Enable curl based network layer for Android" OFF)
+option(OLP_SDK_ENABLE_IOS_BACKGROUND_DOWNLOAD "Enable iOS network layer downloading in background. Under testing." OFF)
 
 # C++ standard version. Minimum supported version is 11.
 set(CMAKE_CXX_STANDARD 11)

olp-cpp-sdk-core/CMakeLists.txt

@@ -400,6 +400,11 @@ endif()
 
 add_library(${PROJECT_NAME} ${OLP_SDK_CORE_SOURCES} ${OLP_SDK_CORE_HEADERS})
 
+if (OLP_SDK_ENABLE_IOS_BACKGROUND_DOWNLOAD)
+    target_compile_definitions(${PROJECT_NAME}
+        PRIVATE OLP_SDK_NETWORK_IOS_BACKGROUND_DOWNLOAD)
+endif()
+
 if (OLP_SDK_DISABLE_DEBUG_LOGGING)
     target_compile_definitions(${PROJECT_NAME}
         PUBLIC LOGGING_DISABLE_DEBUG_LEVEL)

olp-cpp-sdk-core/src/http/ios/OLPHttpClient+Internal.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019-2021 HERE Europe B.V.
+ * Copyright (C) 2019-2023 HERE Europe B.V.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,6 +21,9 @@
 
 #import "OLPHttpClient.h"
 
+#include <olp/core/http/NetworkProxySettings.h>
+#include <olp/core/http/NetworkTypes.h>
+
 /**
  * @brief Internal category, which extends OLPHttpClient with internal methods,
  * which shouldn't be exposed as public API.
@@ -29,11 +32,22 @@
 
 @property(nonatomic, readonly) NSArray* activeTasks;
 
-- (NSURLSession*)urlSessionWithProxy:
-                     (const olp::http::NetworkProxySettings&)proxySettings
-                          andHeaders:(NSDictionary*)headers;
+- (NSMutableDictionary*)toProxyDict:
+    (const olp::http::NetworkProxySettings&)proxySettings;
+
+- (NSURLSession*)urlSessionWithProxy:(NSDictionary*)proxyDict
+                          andHeaders:(NSDictionary*)headers
+                     andBackgroundId:(NSString*)sessionBackgroundId;
+
+- (NSURLSession*)pickSession:(NSDictionary*)proxyDict;
 
-- (void)registerDataTask:(NSURLSessionDataTask*)dataTask
+- (void)registerDataTask:(NSURLSessionTask*)dataTask
              forHttpTask:(OLPHttpTask*)httpTask;
 
+- (NSURLSessionTask*)createSessionTask:(NSURLSession*)session
+                           withRequest:(NSMutableURLRequest*)request
+                    withBackgroundMode:(bool)backgroundMode;
+
+- (void)restartCurrentTasks;
+
 @end

olp-cpp-sdk-core/src/http/ios/OLPHttpClient.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019-2021 HERE Europe B.V.
+ * Copyright (C) 2019-2023 HERE Europe B.V.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -36,6 +36,10 @@ class NetworkProxySettings;
  */
 @interface OLPHttpClient : NSObject
 
+@property(nonatomic) NSMutableDictionary *toIgnoreResponse;
+
+@property(nonatomic) bool inBackground;
+
 /// Creates a task with specific identifier with corresponding settings
 - (OLPHttpTask *)createTaskWithProxy:
                      (const olp::http::NetworkProxySettings &)proxySettings