(Android) Crash when try to close map when it is displayed in black and no tiles

platform/android/MapboxGLAndroidSDK/src/main/java/com/mapbox/mapboxsdk/http/HTTPRequest.java

@@ -10,6 +10,7 @@
 import java.net.ProtocolException;
 import java.net.SocketException;
 import java.net.UnknownHostException;
+import java.util.concurrent.locks.ReentrantLock;
 
 import javax.net.ssl.SSLException;
 
@@ -27,7 +28,10 @@ class HTTPRequest implements Callback {
     private static final int CONNECTION_ERROR = 0;
     private static final int TEMPORARY_ERROR = 1;
     private static final int PERMANENT_ERROR = 2;
-    private static final int CANCELED_ERROR = 3;
+
+    // Reentrancy is not needed, but "Lock" is an
+    // abstract class.
+    private ReentrantLock mLock = new ReentrantLock();
 
     private long mNativePtr = 0;
 
@@ -52,6 +56,15 @@ private HTTPRequest(long nativePtr, String resourceUrl, String userAgent, String
 
     public void cancel() {
         mCall.cancel();
+
+        // TODO: We need a lock here because we can try
+        // to cancel at the same time the request is getting
+        // answered on the OkHTTP thread. We could get rid of
+        // this lock by using Runnable when we move Android
+        // implementation of mbgl::RunLoop to Looper.
+        mLock.lock();
+        mNativePtr = 0;
+        mLock.unlock();
     }
 
     @Override
@@ -77,7 +90,11 @@ public void onResponse(Call call, Response response) throws IOException {
             response.body().close();
         }
 
-        nativeOnResponse(response.code(), response.header("ETag"), response.header("Last-Modified"), response.header("Cache-Control"), response.header("Expires"), body);
+        mLock.lock();
+        if (mNativePtr != 0) {
+            nativeOnResponse(response.code(), response.header("ETag"), response.header("Last-Modified"), response.header("Cache-Control"), response.header("Expires"), body);
+        }
+        mLock.unlock();
     }
 
     @Override
@@ -89,11 +106,14 @@ public void onFailure(Call call, IOException e) {
             type = CONNECTION_ERROR;
         } else if ((e instanceof InterruptedIOException)) {
             type = TEMPORARY_ERROR;
-        } else if (mCall.isCanceled()) {
-            type = CANCELED_ERROR;
         }
 
         String errorMessage = e.getMessage() != null ? e.getMessage() : "Error processing the request";
-        nativeOnFailure(type, errorMessage);
+
+        mLock.lock();
+        if (mNativePtr != 0) {
+            nativeOnFailure(type, errorMessage);
+        }
+        mLock.unlock();
     }
 }

platform/android/src/http_request_android.cpp

@@ -40,8 +40,6 @@ class HTTPRequest : public HTTPRequestBase {
 private:
     void finish();
 
-    bool cancelled = false;
-
     std::unique_ptr<Response> response;
     const std::shared_ptr<const Response> existingResponse;
 
@@ -50,7 +48,6 @@ class HTTPRequest : public HTTPRequestBase {
     static const int connectionError = 0;
     static const int temporaryError = 1;
     static const int permanentError = 2;
-    static const int canceledError = 3;
 };
 
 jni::Class<HTTPRequest> HTTPRequest::javaClass;
@@ -97,20 +94,18 @@ HTTPRequest::HTTPRequest(jni::JNIEnv& env, const Resource& resource_, Callback c
 }
 
 void HTTPRequest::cancel() {
-    cancelled = true;
-
     UniqueEnv env = android::AttachEnv();
 
     static auto cancel = javaClass.GetMethod<void ()>(*env, "cancel");
 
     javaRequest->Call(*env, cancel);
+
+    delete this;
 }
 
 void HTTPRequest::finish() {
-    if (!cancelled) {
-        assert(response);
-        notify(*response);
-    }
+    assert(response);
+    notify(*response);
 
     delete this;
 }
@@ -173,9 +168,6 @@ void HTTPRequest::onFailure(jni::JNIEnv& env, int type, jni::String message) {
         case temporaryError:
             response->error = std::make_unique<Error>(Error::Reason::Server, messageStr);
             break;
-        case canceledError:
-            response.reset();
-            break;
         default:
             response->error = std::make_unique<Error>(Error::Reason::Other, messageStr);
     }