lib: add method to cancel in-flight requests

lib/android/src/main/aidl/im/molly/monero/IRemoteNodeClient.aidl

@@ -6,4 +6,5 @@ import im.molly.monero.RemoteNode;
 interface IRemoteNodeClient {
 //    RemoteNode getRemoteNode();
     HttpResponse makeRequest(String method, String path, String header, in byte[] body);
+    oneway void cancelAll();
 }

lib/android/src/main/cpp/jni_cache.cc

@@ -7,6 +7,7 @@ ScopedJvmGlobalRef<jclass> OwnedTxOut;
 jmethodID HttpResponse_getBody;
 jmethodID HttpResponse_getCode;
 jmethodID HttpResponse_getContentType;
+jmethodID IRemoteNodeClient_cancelAll;
 jmethodID IRemoteNodeClient_makeRequest;
 jmethodID Logger_logFromNative;
 jmethodID OwnedTxOut_ctor;
@@ -29,6 +30,8 @@ void initializeJniCache(JNIEnv* env) {
       .getMethodId(env, "getCode", "()I");
   HttpResponse_getContentType = httpResponse
       .getMethodId(env, "getContentType", "()Ljava/lang/String;");
+  IRemoteNodeClient_cancelAll = iRemoteNodeClient
+      .getMethodId(env, "cancelAll", "()V");
   IRemoteNodeClient_makeRequest = iRemoteNodeClient
       .getMethodId(env,
                    "makeRequest",

lib/android/src/main/cpp/jni_cache.h

@@ -13,6 +13,7 @@ extern ScopedJvmGlobalRef<jclass> OwnedTxOut;
 extern jmethodID HttpResponse_getBody;
 extern jmethodID HttpResponse_getCode;
 extern jmethodID HttpResponse_getContentType;
+extern jmethodID IRemoteNodeClient_cancelAll;
 extern jmethodID IRemoteNodeClient_makeRequest;
 extern jmethodID Logger_logFromNative;
 extern jmethodID OwnedTxOut_ctor;

lib/android/src/main/cpp/wallet.cc

@@ -24,12 +24,13 @@ static_assert(CRYPTONOTE_MAX_BLOCK_NUMBER == 500000000,
 Wallet::Wallet(
     JNIEnv* env,
     int network_id,
-    std::unique_ptr<HttpClientFactory> http_client_factory,
+    const JvmRef<jobject>& remote_node_client,
     const JvmRef<jobject>& callback)
     : m_wallet(static_cast<cryptonote::network_type>(network_id),
                0,    /* kdf_rounds */
                true, /* unattended */
-               std::move(http_client_factory)),
+               std::make_unique<RemoteNodeClientFactory>(env, remote_node_client)),
+      m_remote_node_client(env, remote_node_client),
       m_callback(env, callback),
       m_account_ready(false),
       m_blockchain_height(1),
@@ -212,11 +213,9 @@ Java_im_molly_monero_WalletNative_nativeCreate(
     jobject thiz,
     jint network_id,
     jobject p_remote_node_client) {
-  auto wallet = new Wallet(
-      env, network_id,
-      std::make_unique<RemoteNodeClientFactory>(
-          env, JvmParamRef<jobject>(p_remote_node_client)),
-      JvmParamRef<jobject>(thiz));
+  auto wallet = new Wallet(env, network_id,
+                           JvmParamRef<jobject>(p_remote_node_client),
+                           JvmParamRef<jobject>(thiz));
   return nativeToJvmPointer(wallet);
 }
 

lib/android/src/main/cpp/wallet.h

@@ -24,7 +24,7 @@ class Wallet : tools::i_wallet2_callback {
 
   Wallet(JNIEnv* env,
          int network_id,
-         std::unique_ptr<HttpClientFactory> http_client_factory,
+         const JvmRef<jobject>& remote_node_client,
          const JvmRef<jobject>& callback);
 
   void restoreAccount(const std::vector<char>& secret_scalar, uint64_t account_timestamp);

lib/android/src/main/kotlin/im/molly/monero/RemoteNodeClient.kt

@@ -2,23 +2,23 @@ package im.molly.monero
 
 import android.net.Uri
 import android.os.ParcelFileDescriptor
-import kotlinx.coroutines.CoroutineDispatcher
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.launch
+import kotlinx.coroutines.*
 import okhttp3.*
 import java.io.FileOutputStream
 import java.io.IOException
+import kotlin.coroutines.resumeWithException
 
 internal class RemoteNodeClient(
     private val nodeSelector: RemoteNodeSelector,
     private val httpClient: OkHttpClient,
-    private val scope: CoroutineScope,
-    private val ioDispatcher: CoroutineDispatcher,
+    ioDispatcher: CoroutineDispatcher,
 ) : IRemoteNodeClient.Stub() {
 
     private val logger = loggerFor<RemoteNodeClient>()
 
-    /** Disable connecting to the Monero network */
+    private val requestsScope = CoroutineScope(ioDispatcher + SupervisorJob())
+
+//    /** Disable connecting to the Monero network */
 //    var offline = false
 
     private fun selectedNode() = nodeSelector.select()
@@ -47,6 +47,11 @@ internal class RemoteNodeClient(
         }
     }
 
+    @CalledByNative("http_client.cc")
+    override fun cancelAll() {
+        requestsScope.coroutineContext.cancelChildren()
+    }
+
     private fun execute(
         method: String?,
         uri: Uri,
@@ -56,10 +61,12 @@ internal class RemoteNodeClient(
         password: String?,
     ): HttpResponse {
         logger.d("HTTP: $method $uri, header_len=${header?.length}, body_size=${body?.size}")
+
         val headers = header?.parseHttpHeader()
         val contentType = headers?.get("Content-Type")?.let { value ->
             MediaType.get(value)
         }
+
         val request = with(Request.Builder()) {
             when (method) {
                 "GET" -> {}
@@ -71,16 +78,28 @@ internal class RemoteNodeClient(
             url(uri.toString())
             build()
         }
-        val response = httpClient.newCall(request).execute()
-        return if (response.isSuccessful) {
+
+        val response = runBlocking(requestsScope.coroutineContext) {
+            val call = httpClient.newCall(request)
+            try {
+                call.await()
+            } catch (ioe: IOException) {
+                if (!call.isCanceled) {
+                    throw ioe
+                }
+                null
+            }
+        }
+
+        return if (response == null) {
+            HttpResponse(code = 499)
+        } else if (response.isSuccessful) {
             val responseBody = requireNotNull(response.body())
             val pipe = ParcelFileDescriptor.createPipe()
-            scope.launch(ioDispatcher) {
-                pipe[1].use { readFd ->
-                    FileOutputStream(readFd.fileDescriptor).use { outputStream ->
-                        responseBody.use {
-                            it.byteStream().copyTo(outputStream)
-                        }
+            requestsScope.launch {
+                pipe[1].use { writeSide ->
+                    FileOutputStream(writeSide.fileDescriptor).use { outputStream ->
+                        responseBody.byteStream().copyTo(outputStream)
                     }
                 }
             }
@@ -90,13 +109,28 @@ internal class RemoteNodeClient(
                 body = pipe[0],
             )
         } else {
-            HttpResponse(code = response.code()).also {
-                response.close()
-            }
+            HttpResponse(code = response.code())
         }
     }
 
-    private fun String.parseHttpHeader(): Headers =
+    @OptIn(ExperimentalCoroutinesApi::class)
+    private suspend fun Call.await() = suspendCancellableCoroutine { continuation ->
+        enqueue(object : Callback {
+            override fun onResponse(call: Call, response: Response) {
+                continuation.resume(response) {
+                    response.close()
+                }
+            }
+
+            override fun onFailure(call: Call, e: IOException) {
+                continuation.resumeWithException(e)
+            }
+        })
+
+        continuation.invokeOnCancellation { cancel() }
+    }
+
+    fun String.parseHttpHeader(): Headers =
         with(Headers.Builder()) {
             splitToSequence("\r\n")
                 .filter { line -> line.isNotEmpty() }

lib/android/src/main/kotlin/im/molly/monero/WalletClient.kt

@@ -39,13 +39,11 @@ class WalletClient private constructor(
             network: MoneroNetwork,
             nodeSelector: RemoteNodeSelector? = null,
             httpClient: OkHttpClient? = null,
-            coroutineContext: CoroutineContext = Dispatchers.Default + SupervisorJob(),
             ioDispatcher: CoroutineDispatcher = Dispatchers.IO,
         ): WalletClient {
-            val scope = CoroutineScope(coroutineContext)
             val remoteNodeClient = nodeSelector?.let {
                 requireNotNull(httpClient)
-                RemoteNodeClient(it, httpClient, scope, ioDispatcher)
+                RemoteNodeClient(it, httpClient, ioDispatcher)
             }
             val (serviceConnection, service) = bindService(context)
             return WalletClient(context, service, serviceConnection, network, remoteNodeClient)