android: Re-create fakeClientFd for every loolwsd restart.

Also remember it in the thread itself, otherwise we are likely to close
the newly created one, instead of the old one (when loading the document
the 2nd time).

[This is the most important piece of the '2nd start crashes' puzzle.]

Change-Id: I3bb89882b6f3ac1493c47a27b4c4589b6996afab

android/app/src/main/cpp/androidapp.cpp

@@ -134,6 +134,10 @@ Java_org_libreoffice_androidapp_MainActivity_postMobileMessageNative(JNIEnv *env
     {
         LOG_DBG("From JS: lool: " << string_value);
 
+        // we need a copy, because we can get a new one while we are still
+        // taking down the old one
+        const int currentFakeClientFd = fakeClientFd;
+
         if (strcmp(string_value, "HULLO") == 0)
         {
             // Now we know that the JS has started completely
@@ -141,7 +145,8 @@ Java_org_libreoffice_androidapp_MainActivity_postMobileMessageNative(JNIEnv *env
             // Contact the permanently (during app lifetime) listening LOOLWSD server
             // "public" socket
             assert(loolwsd_server_socket_fd != -1);
-            int rc = fakeSocketConnect(fakeClientFd, loolwsd_server_socket_fd);
+
+            int rc = fakeSocketConnect(currentFakeClientFd, loolwsd_server_socket_fd);
             assert(rc != -1);
 
             // Create a socket pair to notify the below thread when the document has been closed
@@ -152,13 +157,13 @@ Java_org_libreoffice_androidapp_MainActivity_postMobileMessageNative(JNIEnv *env
             jclass mainActivityClz = (jclass) env->NewGlobalRef(clz);
             jobject mainActivityObj = env->NewGlobalRef(instance);
 
-            std::thread([&mainActivityClz, &mainActivityObj]
+            std::thread([&mainActivityClz, &mainActivityObj, currentFakeClientFd]
                         {
                             Util::setThreadName("app2js");
                             while (true)
                             {
                                struct pollfd pollfd[2];
-                               pollfd[0].fd = fakeClientFd;
+                               pollfd[0].fd = currentFakeClientFd;
                                pollfd[0].events = POLLIN;
                                pollfd[1].fd = closeNotificationPipeForForwardingThread[1];
                                pollfd[1].events = POLLIN;
@@ -166,6 +171,7 @@ Java_org_libreoffice_androidapp_MainActivity_postMobileMessageNative(JNIEnv *env
                                {
                                    if (pollfd[1].revents == POLLIN)
                                    {
+                                       LOG_DBG("app2js: closing the sockets");
                                        // The code below handling the "BYE" fake Websocket
                                        // message has closed the other end of the
                                        // closeNotificationPipeForForwardingThread. Let's close
@@ -180,17 +186,17 @@ Java_org_libreoffice_androidapp_MainActivity_postMobileMessageNative(JNIEnv *env
 
                                        // Close our end of the fake socket connection to the
                                        // ClientSession thread, so that it terminates
-                                       fakeSocketClose(fakeClientFd);
+                                       fakeSocketClose(currentFakeClientFd);
 
                                        return;
                                    }
                                    if (pollfd[0].revents == POLLIN)
                                    {
-                                       int n = fakeSocketAvailableDataLength(fakeClientFd);
+                                       int n = fakeSocketAvailableDataLength(currentFakeClientFd);
                                        if (n == 0)
                                            return;
                                        std::vector<char> buf(n);
-                                       n = fakeSocketRead(fakeClientFd, buf.data(), n);
+                                       n = fakeSocketRead(currentFakeClientFd, buf.data(), n);
                                        send2JS(mainActivityClz, mainActivityObj, buf);
                                    }
                                }
@@ -205,13 +211,13 @@ Java_org_libreoffice_androidapp_MainActivity_postMobileMessageNative(JNIEnv *env
             LOG_DBG("Actually sending to Online:" << fileURL);
 
             // Must do this in a thread, too, so that we can return to the GTK+ main loop
-            std::thread([]
+            std::thread([=]
                         {
                             struct pollfd pollfd;
-                            pollfd.fd = fakeClientFd;
+                            pollfd.fd = currentFakeClientFd;
                             pollfd.events = POLLOUT;
                             fakeSocketPoll(&pollfd, 1, -1);
-                            fakeSocketWrite(fakeClientFd, fileURL.c_str(), fileURL.size());
+                            fakeSocketWrite(currentFakeClientFd, fileURL.c_str(), fileURL.size());
                         }).detach();
         }
         else if (strcmp(string_value, "BYE") == 0)
@@ -220,8 +226,6 @@ Java_org_libreoffice_androidapp_MainActivity_postMobileMessageNative(JNIEnv *env
 
             // Close one end of the socket pair, that will wake up the forwarding thread above
             fakeSocketClose(closeNotificationPipeForForwardingThread[0]);
-
-            // ???
         }
         else if (strcmp(string_value, "PRINT") == 0 && false /* FIXME disabled so far */)
         {
@@ -238,10 +242,10 @@ Java_org_libreoffice_androidapp_MainActivity_postMobileMessageNative(JNIEnv *env
             std::thread([=]
                         {
                             struct pollfd pollfd;
-                            pollfd.fd = fakeClientFd;
+                            pollfd.fd = currentFakeClientFd;
                             pollfd.events = POLLOUT;
                             fakeSocketPoll(&pollfd, 1, -1);
-                            fakeSocketWrite(fakeClientFd, string_copy, strlen(string_copy));
+                            fakeSocketWrite(currentFakeClientFd, string_copy, strlen(string_copy));
                             free(string_copy);
                         }).detach();
         }
@@ -282,6 +286,8 @@ Java_org_libreoffice_androidapp_MainActivity_createLOOLWSD(JNIEnv *env, jobject,
                     {
                         LOG_DBG("Creating LOOLWSD");
                         {
+                            fakeClientFd = fakeSocketSocket();
+                            LOG_DBG("createLOOLWSD created fakeClientFd: " << fakeClientFd);
                             std::unique_ptr<LOOLWSD> loolwsd(new LOOLWSD());
                             loolwsd->run(1, argv);
                         }
@@ -289,9 +295,6 @@ Java_org_libreoffice_androidapp_MainActivity_createLOOLWSD(JNIEnv *env, jobject,
                         std::this_thread::sleep_for(std::chrono::milliseconds(100));
                     }
                 }).detach();
-
-    fakeClientFd = fakeSocketSocket();
-    LOG_DBG("createLOOLWSD created fakeClientFd: " << fakeClientFd);
 }
 
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