Revert "Clean up remains of NativeActivity-based Android app support"

This reverts commit cecc926070ee3d2ad6296fc5e0cfcde8642bb140.

Conflicts:
sal/android/lo-bootstrap.c
sal/inc/osl/detail/android-bootstrap.h

9 files changed, 971 insertions, 20 deletions

diff --git a/sal/Library_sal.mk b/sal/Library_sal.mk
index 533fb6c2c777..0bd28fae2f00 100644
--- a/sal/Library_sal.mk
+++ b/sal/Library_sal.mk
@@ -181,7 +181,7 @@ $(eval $(call gb_Library_add_exception_objects,sal,\
 	sal/osl/unx/module \
 	sal/osl/unx/process \
 	sal/osl/unx/process_impl \
-        $(if $(filter DESKTOP,$(BUILD_TYPE)), sal/osl/unx/salinit) \
+	sal/osl/unx/salinit \
 	sal/osl/unx/uunxapi \
 ))
 $(eval $(call gb_Library_add_cobjects,sal,\
diff --git a/sal/Module_sal.mk b/sal/Module_sal.mk
index 7d20fa388992..af97e4805703 100644
--- a/sal/Module_sal.mk
+++ b/sal/Module_sal.mk
@@ -31,8 +31,7 @@ $(eval $(call gb_Module_Module,sal))
 $(eval $(call gb_Module_add_targets,sal,\
 	CustomTarget_generated \
 	CustomTarget_sal_allheaders \
-	$(if $(filter DESKTOP,$(BUILD_TYPE)), \
-		Executable_cppunittester) \
+	Executable_cppunittester \
 	$(if $(filter $(OS),ANDROID), \
 		Library_lo-bootstrap) \
 	Library_sal \
@@ -46,14 +45,13 @@ $(eval $(call gb_Module_add_targets,sal,\
 ))
 
 ifneq (,$(filter DESKTOP,$(BUILD_TYPE)))
-
 $(eval $(call gb_Module_add_targets,sal,\
 		Executable_osl_process_child \
 ))
-
 $(eval $(call gb_Module_add_check_targets,sal,\
 		CppunitTest_sal_osl_process \
 ))
+endif
 
 $(eval $(call gb_Module_add_check_targets,sal,\
 	$(if $(filter TRUE,$(DISABLE_DYNLOADING)),,CppunitTest_Module_DLL) \
@@ -90,8 +88,6 @@ $(eval $(call gb_Module_add_check_targets,sal,\
 	CppunitTest_sal_rtl_math \
 ))
 
-endif
-
 # CppunitTest_sal_osl_pipe has circular dependency on unotest
 # $(eval $(call gb_Module_add_subsequentcheck_targets,sal,\
 	CppunitTest_sal_osl_pipe \
diff --git a/sal/Package_inc.mk b/sal/Package_inc.mk
index 15fb47717d35..0b78afdff514 100644
--- a/sal/Package_inc.mk
+++ b/sal/Package_inc.mk
@@ -61,6 +61,7 @@ $(eval $(call gb_Package_add_file,sal_inc,inc/osl/thread.hxx,osl/thread.hxx))
 $(eval $(call gb_Package_add_file,sal_inc,inc/osl/time.h,osl/time.h))
 $(eval $(call gb_Package_add_file,sal_inc,inc/osl/util.h,osl/util.h))
 $(eval $(call gb_Package_add_file,sal_inc,inc/osl/detail/file.h,osl/detail/file.h))
+$(eval $(call gb_Package_add_file,sal_inc,inc/osl/detail/android_native_app_glue.h,osl/detail/android_native_app_glue.h))
 $(eval $(call gb_Package_add_file,sal_inc,inc/osl/detail/android-bootstrap.h,osl/detail/android-bootstrap.h))
 $(eval $(call gb_Package_add_file,sal_inc,inc/osl/detail/ios-bootstrap.h,osl/detail/ios-bootstrap.h))
 $(eval $(call gb_Package_add_file,sal_inc,inc/osl/detail/component-mapping.h,osl/detail/component-mapping.h))
diff --git a/sal/android/android_native_app_glue.c b/sal/android/android_native_app_glue.c
new file mode 100644
index 000000000000..0c2dd5e92f39
--- /dev/null
+++ b/sal/android/android_native_app_glue.c
@@ -0,0 +1,459 @@
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Copyright (C) 2010 The Android Open Source Project
+ *
+ *   Licensed under the Apache License, Version 2.0 (the "License");
+ *   you may not use this file except in compliance with the License.
+ *   You may obtain a copy of the License at
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ */
+
+#include <jni.h>
+
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/resource.h>
+
+#include "osl/detail/android-bootstrap.h"
+#include "osl/detail/android_native_app_glue.h"
+#include <android/log.h>
+
+#define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO, "lo-bootstrap", __VA_ARGS__))
+
+static void free_saved_state(struct android_app* android_app) {
+    pthread_mutex_lock(&android_app->mutex);
+    if (android_app->savedState != NULL) {
+        free(android_app->savedState);
+        android_app->savedState = NULL;
+        android_app->savedStateSize = 0;
+    }
+    pthread_mutex_unlock(&android_app->mutex);
+}
+
+int8_t android_app_read_cmd(struct android_app* android_app) {
+    int8_t cmd;
+    if (read(android_app->msgread, &cmd, sizeof(cmd)) == sizeof(cmd)) {
+        switch (cmd) {
+            case APP_CMD_SAVE_STATE:
+                free_saved_state(android_app);
+                break;
+        }
+        return cmd;
+    } else {
+        LOGI("No data on command pipe!");
+    }
+    return -1;
+}
+
+static void print_cur_config(struct android_app* android_app) {
+    char lang[2], country[2];
+    AConfiguration_getLanguage(android_app->config, lang);
+    AConfiguration_getCountry(android_app->config, country);
+
+    LOGI("Config: mcc=%d mnc=%d lang=%c%c cnt=%c%c orien=%d touch=%d dens=%d "
+            "keys=%d nav=%d keysHid=%d navHid=%d sdk=%d size=%d long=%d "
+            "modetype=%d modenight=%d",
+            AConfiguration_getMcc(android_app->config),
+            AConfiguration_getMnc(android_app->config),
+            lang[0], lang[1], country[0], country[1],
+            AConfiguration_getOrientation(android_app->config),
+            AConfiguration_getTouchscreen(android_app->config),
+            AConfiguration_getDensity(android_app->config),
+            AConfiguration_getKeyboard(android_app->config),
+            AConfiguration_getNavigation(android_app->config),
+            AConfiguration_getKeysHidden(android_app->config),
+            AConfiguration_getNavHidden(android_app->config),
+            AConfiguration_getSdkVersion(android_app->config),
+            AConfiguration_getScreenSize(android_app->config),
+            AConfiguration_getScreenLong(android_app->config),
+            AConfiguration_getUiModeType(android_app->config),
+            AConfiguration_getUiModeNight(android_app->config));
+}
+
+void android_app_pre_exec_cmd(struct android_app* android_app, int8_t cmd) {
+    switch (cmd) {
+        case APP_CMD_INPUT_CHANGED:
+            LOGI("APP_CMD_INPUT_CHANGED\n");
+            pthread_mutex_lock(&android_app->mutex);
+            if (android_app->inputQueue != NULL) {
+                AInputQueue_detachLooper(android_app->inputQueue);
+            }
+            android_app->inputQueue = android_app->pendingInputQueue;
+            if (android_app->inputQueue != NULL) {
+                LOGI("Attaching input queue to looper");
+                AInputQueue_attachLooper(android_app->inputQueue,
+                        android_app->looper, LOOPER_ID_INPUT, NULL,
+                        &android_app->inputPollSource);
+            }
+            pthread_cond_broadcast(&android_app->cond);
+            pthread_mutex_unlock(&android_app->mutex);
+            break;
+
+        case APP_CMD_INIT_WINDOW:
+            LOGI("APP_CMD_INIT_WINDOW\n");
+            pthread_mutex_lock(&android_app->mutex);
+            android_app->window = android_app->pendingWindow;
+            pthread_cond_broadcast(&android_app->cond);
+            pthread_mutex_unlock(&android_app->mutex);
+            break;
+
+        case APP_CMD_TERM_WINDOW:
+            LOGI("APP_CMD_TERM_WINDOW\n");
+            pthread_cond_broadcast(&android_app->cond);
+            break;
+
+        case APP_CMD_RESUME:
+        case APP_CMD_START:
+        case APP_CMD_PAUSE:
+        case APP_CMD_STOP:
+            LOGI("activityState=%d\n", cmd);
+            pthread_mutex_lock(&android_app->mutex);
+            android_app->activityState = cmd;
+            pthread_cond_broadcast(&android_app->cond);
+            pthread_mutex_unlock(&android_app->mutex);
+            break;
+
+        case APP_CMD_CONFIG_CHANGED:
+            LOGI("APP_CMD_CONFIG_CHANGED\n");
+            AConfiguration_fromAssetManager(android_app->config,
+                    android_app->activity->assetManager);
+            print_cur_config(android_app);
+            break;
+
+        case APP_CMD_DESTROY:
+            LOGI("APP_CMD_DESTROY\n");
+            android_app->destroyRequested = 1;
+            break;
+    }
+}
+
+void android_app_post_exec_cmd(struct android_app* android_app, int8_t cmd) {
+    switch (cmd) {
+        case APP_CMD_TERM_WINDOW:
+            LOGI("APP_CMD_TERM_WINDOW\n");
+            pthread_mutex_lock(&android_app->mutex);
+            android_app->window = NULL;
+            pthread_cond_broadcast(&android_app->cond);
+            pthread_mutex_unlock(&android_app->mutex);
+            break;
+        case APP_CMD_WINDOW_REDRAW_NEEDED:
+            LOGI("APP_CMD_WINDOW_REDRAW_NEEDED - post\n");
+            pthread_mutex_lock(&android_app->mutex);
+            pthread_cond_broadcast(&android_app->cond);
+            pthread_mutex_unlock(&android_app->mutex);
+	    break;
+
+        case APP_CMD_SAVE_STATE:
+            LOGI("APP_CMD_SAVE_STATE\n");
+            pthread_mutex_lock(&android_app->mutex);
+            android_app->stateSaved = 1;
+            pthread_cond_broadcast(&android_app->cond);
+            pthread_mutex_unlock(&android_app->mutex);
+            break;
+
+        case APP_CMD_RESUME:
+            free_saved_state(android_app);
+            break;
+    }
+}
+
+void app_dummy() {
+
+}
+
+static void android_app_destroy(struct android_app* android_app) {
+    LOGI("android_app_destroy!");
+    free_saved_state(android_app);
+    pthread_mutex_lock(&android_app->mutex);
+    if (android_app->inputQueue != NULL) {
+        AInputQueue_detachLooper(android_app->inputQueue);
+    }
+    AConfiguration_delete(android_app->config);
+    android_app->destroyed = 1;
+    pthread_cond_broadcast(&android_app->cond);
+    pthread_mutex_unlock(&android_app->mutex);
+    // Can't touch android_app object after this.
+}
+
+static void process_input(struct android_app* app, struct android_poll_source* source) {
+    AInputEvent* event = NULL;
+    (void) source;
+    if (AInputQueue_getEvent(app->inputQueue, &event) >= 0) {
+        LOGI("New input event: type=%d\n", AInputEvent_getType(event));
+        if (AInputQueue_preDispatchEvent(app->inputQueue, event)) {
+            return;
+        }
+        int32_t handled = 0;
+        if (app->onInputEvent != NULL) handled = app->onInputEvent(app, event);
+        AInputQueue_finishEvent(app->inputQueue, event, handled);
+    } else {
+        LOGI("Failure reading next input event: %s\n", strerror(errno));
+    }
+}
+
+static void process_cmd(struct android_app* app, struct android_poll_source* source) {
+    int8_t cmd = android_app_read_cmd(app);
+    (void) source;
+    android_app_pre_exec_cmd(app, cmd);
+    if (app->onAppCmd != NULL) app->onAppCmd(app, cmd);
+    android_app_post_exec_cmd(app, cmd);
+}
+
+static void* android_app_entry(void* param) {
+    struct android_app* android_app = (struct android_app*)param;
+
+    android_app->config = AConfiguration_new();
+    AConfiguration_fromAssetManager(android_app->config, android_app->activity->assetManager);
+
+    print_cur_config(android_app);
+
+    android_app->cmdPollSource.id = LOOPER_ID_MAIN;
+    android_app->cmdPollSource.app = android_app;
+    android_app->cmdPollSource.process = process_cmd;
+    android_app->inputPollSource.id = LOOPER_ID_INPUT;
+    android_app->inputPollSource.app = android_app;
+    android_app->inputPollSource.process = process_input;
+
+    ALooper* looper = ALooper_prepare(ALOOPER_PREPARE_ALLOW_NON_CALLBACKS);
+    ALooper_addFd(looper, android_app->msgread, LOOPER_ID_MAIN, ALOOPER_EVENT_INPUT, NULL,
+            &android_app->cmdPollSource);
+    android_app->looper = looper;
+
+    pthread_mutex_lock(&android_app->mutex);
+    android_app->running = 1;
+    pthread_cond_broadcast(&android_app->cond);
+    pthread_mutex_unlock(&android_app->mutex);
+
+    android_main(android_app);
+
+    android_app_destroy(android_app);
+    return NULL;
+}
+
+// --------------------------------------------------------------------
+// Native activity interaction (called from main thread)
+// --------------------------------------------------------------------
+
+static struct android_app* android_app_create(ANativeActivity* activity,
+        void* savedState, size_t savedStateSize) {
+    struct android_app* android_app = (struct android_app*)malloc(sizeof(struct android_app));
+    memset(android_app, 0, sizeof(struct android_app));
+    android_app->activity = activity;
+
+    pthread_mutex_init(&android_app->mutex, NULL);
+    pthread_cond_init(&android_app->cond, NULL);
+
+    if (savedState != NULL) {
+        android_app->savedState = malloc(savedStateSize);
+        android_app->savedStateSize = savedStateSize;
+        memcpy(android_app->savedState, savedState, savedStateSize);
+    }
+
+    int msgpipe[2];
+    if (pipe(msgpipe)) {
+        LOGI("could not create pipe: %s", strerror(errno));
+    }
+    android_app->msgread = msgpipe[0];
+    android_app->msgwrite = msgpipe[1];
+
+    pthread_attr_t attr;
+    pthread_attr_init(&attr);
+    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
+    pthread_create(&android_app->thread, &attr, android_app_entry, android_app);
+
+    // Wait for thread to start.
+    pthread_mutex_lock(&android_app->mutex);
+    while (!android_app->running) {
+        pthread_cond_wait(&android_app->cond, &android_app->mutex);
+    }
+    pthread_mutex_unlock(&android_app->mutex);
+
+    return android_app;
+}
+
+static void android_app_write_cmd(struct android_app* android_app, int8_t cmd) {
+    if (write(android_app->msgwrite, &cmd, sizeof(cmd)) != sizeof(cmd)) {
+        LOGI("Failure writing android_app cmd: %s\n", strerror(errno));
+    }
+}
+
+static void android_app_set_input(struct android_app* android_app, AInputQueue* inputQueue) {
+    pthread_mutex_lock(&android_app->mutex);
+    android_app->pendingInputQueue = inputQueue;
+    android_app_write_cmd(android_app, APP_CMD_INPUT_CHANGED);
+    while (android_app->inputQueue != android_app->pendingInputQueue) {
+        pthread_cond_wait(&android_app->cond, &android_app->mutex);
+    }
+    pthread_mutex_unlock(&android_app->mutex);
+}
+
+static void android_app_set_window(struct android_app* android_app, ANativeWindow* window) {
+    pthread_mutex_lock(&android_app->mutex);
+    if (android_app->pendingWindow != NULL) {
+        android_app_write_cmd(android_app, APP_CMD_TERM_WINDOW);
+    }
+    android_app->pendingWindow = window;
+    if (window != NULL) {
+        android_app_write_cmd(android_app, APP_CMD_INIT_WINDOW);
+    }
+    while (android_app->window != android_app->pendingWindow) {
+        pthread_cond_wait(&android_app->cond, &android_app->mutex);
+    }
+    pthread_mutex_unlock(&android_app->mutex);
+}
+
+static void android_app_window_redraw_needed(struct android_app* android_app, ANativeWindow* window) {
+    pthread_mutex_lock(&android_app->mutex);
+    if (window != NULL) {
+        android_app_write_cmd(android_app, APP_CMD_WINDOW_REDRAW_NEEDED);
+    }
+    while (android_app->window != android_app->pendingWindow) {
+        pthread_cond_wait(&android_app->cond, &android_app->mutex);
+    }
+    pthread_mutex_unlock(&android_app->mutex);
+}
+
+static void android_app_set_activity_state(struct android_app* android_app, int8_t cmd) {
+    pthread_mutex_lock(&android_app->mutex);
+    android_app_write_cmd(android_app, cmd);
+    while (android_app->activityState != cmd) {
+        pthread_cond_wait(&android_app->cond, &android_app->mutex);
+    }
+    pthread_mutex_unlock(&android_app->mutex);
+}
+
+static void android_app_free(struct android_app* android_app) {
+    pthread_mutex_lock(&android_app->mutex);
+    android_app_write_cmd(android_app, APP_CMD_DESTROY);
+    while (!android_app->destroyed) {
+        pthread_cond_wait(&android_app->cond, &android_app->mutex);
+    }
+    pthread_mutex_unlock(&android_app->mutex);
+
+    close(android_app->msgread);
+    close(android_app->msgwrite);
+    pthread_cond_destroy(&android_app->cond);
+    pthread_mutex_destroy(&android_app->mutex);
+    free(android_app);
+}
+
+static void onDestroy(ANativeActivity* activity) {
+    LOGI("Destroy: %p\n", activity);
+    android_app_free((struct android_app*)activity->instance);
+}
+
+static void onStart(ANativeActivity* activity) {
+    LOGI("Start: %p\n", activity);
+    android_app_set_activity_state((struct android_app*)activity->instance, APP_CMD_START);
+}
+
+static void onResume(ANativeActivity* activity) {
+    LOGI("Resume: %p\n", activity);
+    android_app_set_activity_state((struct android_app*)activity->instance, APP_CMD_RESUME);
+}
+
+static void* onSaveInstanceState(ANativeActivity* activity, size_t* outLen) {
+    struct android_app* android_app = (struct android_app*)activity->instance;
+    void* savedState = NULL;
+
+    LOGI("SaveInstanceState: %p\n", activity);
+    pthread_mutex_lock(&android_app->mutex);
+    android_app->stateSaved = 0;
+    android_app_write_cmd(android_app, APP_CMD_SAVE_STATE);
+    while (!android_app->stateSaved) {
+        pthread_cond_wait(&android_app->cond, &android_app->mutex);
+    }
+
+    if (android_app->savedState != NULL) {
+        savedState = android_app->savedState;
+        *outLen = android_app->savedStateSize;
+        android_app->savedState = NULL;
+        android_app->savedStateSize = 0;
+    }
+
+    pthread_mutex_unlock(&android_app->mutex);
+
+    return savedState;
+}
+
+static void onPause(ANativeActivity* activity) {
+    LOGI("Pause: %p\n", activity);
+    android_app_set_activity_state((struct android_app*)activity->instance, APP_CMD_PAUSE);
+}
+
+static void onStop(ANativeActivity* activity) {
+    LOGI("Stop: %p\n", activity);
+    android_app_set_activity_state((struct android_app*)activity->instance, APP_CMD_STOP);
+}
+
+static void onConfigurationChanged(ANativeActivity* activity) {
+    struct android_app* android_app = (struct android_app*)activity->instance;
+    LOGI("ConfigurationChanged: %p\n", activity);
+    android_app_write_cmd(android_app, APP_CMD_CONFIG_CHANGED);
+}
+
+static void onLowMemory(ANativeActivity* activity) {
+    struct android_app* android_app = (struct android_app*)activity->instance;
+    LOGI("LowMemory: %p\n", activity);
+    android_app_write_cmd(android_app, APP_CMD_LOW_MEMORY);
+}
+
+static void onWindowFocusChanged(ANativeActivity* activity, int focused) {
+    LOGI("WindowFocusChanged: %p -- %d\n", activity, focused);
+    android_app_write_cmd((struct android_app*)activity->instance,
+            focused ? APP_CMD_GAINED_FOCUS : APP_CMD_LOST_FOCUS);
+}
+
+static void onNativeWindowCreated(ANativeActivity* activity, ANativeWindow* window) {
+    LOGI("NativeWindowCreated: %p -- %p\n", activity, window);
+    android_app_set_window((struct android_app*)activity->instance, window);
+}
+
+static void onNativeWindowDestroyed(ANativeActivity* activity, ANativeWindow* window) {
+    LOGI("NativeWindowDestroyed: %p -- %p\n", activity, window);
+    android_app_set_window((struct android_app*)activity->instance, NULL);
+}
+
+static void onNativeWindowRedrawNeeded(ANativeActivity* activity, ANativeWindow* window) {
+    LOGI("onNativeWindowRedrawNeeded: %p -- %p\n", activity, window);
+    android_app_window_redraw_needed((struct android_app*)activity->instance, window);
+}
+
+static void onInputQueueCreated(ANativeActivity* activity, AInputQueue* queue) {
+    LOGI("InputQueueCreated: %p -- %p\n", activity, queue);
+    android_app_set_input((struct android_app*)activity->instance, queue);
+}
+
+static void onInputQueueDestroyed(ANativeActivity* activity, AInputQueue* queue) {
+    LOGI("InputQueueDestroyed: %p -- %p\n", activity, queue);
+    android_app_set_input((struct android_app*)activity->instance, NULL);
+}
+
+__attribute__ ((visibility("default"))) void ANativeActivity_onCreate(ANativeActivity* activity,
+        void* savedState, size_t savedStateSize) {
+    LOGI("Creating: %p\n", activity);
+    activity->callbacks->onDestroy = onDestroy;
+    activity->callbacks->onStart = onStart;
+    activity->callbacks->onResume = onResume;
+    activity->callbacks->onSaveInstanceState = onSaveInstanceState;
+    activity->callbacks->onPause = onPause;
+    activity->callbacks->onStop = onStop;
+    activity->callbacks->onConfigurationChanged = onConfigurationChanged;
+    activity->callbacks->onLowMemory = onLowMemory;
+    activity->callbacks->onWindowFocusChanged = onWindowFocusChanged;
+    activity->callbacks->onNativeWindowCreated = onNativeWindowCreated;
+    activity->callbacks->onNativeWindowDestroyed = onNativeWindowDestroyed;
+    activity->callbacks->onNativeWindowRedrawNeeded = onNativeWindowRedrawNeeded;
+    activity->callbacks->onInputQueueCreated = onInputQueueCreated;
+    activity->callbacks->onInputQueueDestroyed = onInputQueueDestroyed;
+
+    activity->instance = android_app_create(activity, savedState, savedStateSize);
+}
diff --git a/sal/android/lo-bootstrap.c b/sal/android/lo-bootstrap.c
index 61f2c7671977..9aeb32be4b21 100644
--- a/sal/android/lo-bootstrap.c
+++ b/sal/android/lo-bootstrap.c
@@ -30,22 +30,19 @@
  * instead of those above.
  */
 
-#include <errno.h>
-#include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
 #include <sys/stat.h>
 #include <sys/time.h>
-#include <time.h>
 
-#include <dlfcn.h>
+#include <unistd.h>
 #include <fcntl.h>
-#include <pthread.h>
+#include <dlfcn.h>
 #include <sys/mman.h>
-#include <unistd.h>
 
-#include <jni.h>
 #include <zlib.h>
+#include <jni.h>
 
 #include <android/log.h>
 
@@ -53,6 +50,12 @@
 
 #include "osl/detail/android-bootstrap.h"
 
+#pragma GCC diagnostic ignored "-Wdeclaration-after-statement"
+
+#include "android_native_app_glue.c"
+
+#pragma GCC diagnostic warning "-Wdeclaration-after-statement"
+
 #undef LOGI
 #undef LOGW
 
@@ -69,6 +72,15 @@ struct engine {
     int dummy;
 };
 
+/* These vars are valid / used only when this library is used from
+ *  NativeActivity-based apps.
+ */
+static struct android_app *app;
+static int (*lo_main)(int, const char **);
+static int lo_main_argc;
+static const char **lo_main_argv;
+static int sleep_time = 0;
+
 /* These are valid / used in all apps. */
 static const char *data_dir;
 static const char *cache_dir;
@@ -266,6 +278,26 @@ setup_assets_tree(void)
     return 1;
 }
 
+static void
+engine_handle_cmd(struct android_app* state,
+                  int32_t cmd)
+{
+    (void) state;
+
+    switch (cmd) {
+    case APP_CMD_SAVE_STATE:
+        break;
+    case APP_CMD_INIT_WINDOW:
+        break;
+    case APP_CMD_TERM_WINDOW:
+        break;
+    case APP_CMD_GAINED_FOCUS:
+        break;
+    case APP_CMD_LOST_FOCUS:
+        break;
+    }
+}
+
 /* The lo-native-code shared library is always loaded from Java, so this is
  * always called by JNI first.
  */
@@ -372,6 +404,7 @@ get_jni_string_array(JNIEnv *env,
         const char *s = (*env)->GetStringUTFChars(env, (*env)->GetObjectArrayElement(env, strv, i), NULL);
         (*argv)[i] = strdup(s);
         (*env)->ReleaseStringUTFChars(env, (*env)->GetObjectArrayElement(env, strv, i), s);
+        /* LOGI("argv[%d] = %s", i, lo_main_argv[i]); */
     }
     (*argv)[*argc] = NULL;
 
@@ -379,6 +412,26 @@ get_jni_string_array(JNIEnv *env,
 }
 
 
+// public static native boolean setup(Object lo_main_argument,
+//                                    int lo_main_delay);
+
+__attribute__ ((visibility("default")))
+jboolean
+Java_org_libreoffice_android_Bootstrap_setup__Ljava_lang_Object_2I(JNIEnv* env,
+                                                                    jobject clazz,
+                                                                    jobject lo_main_argument,
+                                                                    jint lo_main_delay)
+{
+    (void) clazz;
+
+    if (!get_jni_string_array(env, "setup: lo_main_argument", lo_main_argument, &lo_main_argc, &lo_main_argv))
+        return JNI_FALSE;
+
+    sleep_time = lo_main_delay;
+
+    return JNI_TRUE;
+}
+
 // public static native int getpid();
 
 __attribute__ ((visibility("default")))
@@ -1257,4 +1310,59 @@ lo_get_app_data_dir(void)
     return data_dir;
 }
 
+__attribute__ ((visibility("default")))
+struct android_app *
+lo_get_app(void)
+{
+    return app;
+}
+
+/* Note that android_main() is used only in NativeActivity-based apps.  Only
+ * the android/qa/sc unit test app is such, and it is unclear whether there is
+ * any reason to continue maintaining that buildable.
+ */
+__attribute__ ((visibility("default")))
+void
+android_main(struct android_app* state)
+{
+    jint nRet;
+    JNIEnv *pEnv = NULL;
+    struct engine engine;
+    Dl_info lo_main_info;
+    JavaVMAttachArgs aArgs = {
+        JNI_VERSION_1_2,
+        "LibreOfficeThread",
+        NULL
+    };
+
+    fprintf (stderr, "android_main in thread: %d\n", (int)pthread_self());
+
+    if (sleep_time != 0) {
+        LOGI("android_main: Sleeping for %d seconds, start ndk-gdb NOW if that is your intention", sleep_time);
+        sleep(sleep_time);
+    }
+
+    nRet = (*(*state->activity->vm)->AttachCurrentThreadAsDaemon)(state->activity->vm, &pEnv, &aArgs);
+    fprintf (stderr, "attach thread returned %d %p\n", nRet, pEnv);
+
+    app = state;
+
+    memset(&engine, 0, sizeof(engine));
+    state->userData = &engine;
+    state->onAppCmd = engine_handle_cmd;
+
+    /* Look up lo_main() dynamically even if it is in the same .so as this code,
+     * but that is only in the case for code built to be used in a NativeActivity-based app.
+     */
+    lo_main = dlsym(RTLD_DEFAULT, "lo_main");
+
+    if (dladdr(lo_main, &lo_main_info) != 0) {
+        lo_main_argv[0] = lo_main_info.dli_fname;
+    }
+
+    lo_main(lo_main_argc, lo_main_argv);
+    nRet = (*(*state->activity->vm)->DetachCurrentThread)(state->activity->vm);
+    fprintf (stderr, "exit android_main\n");
+}
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sal/inc/osl/detail/android-bootstrap.h b/sal/inc/osl/detail/android-bootstrap.h
index 672536f25f35..d1022f90637e 100644
--- a/sal/inc/osl/detail/android-bootstrap.h
+++ b/sal/inc/osl/detail/android-bootstrap.h
@@ -62,6 +62,8 @@ JavaVM *lo_get_javavm(void);
 
 const char *lo_get_app_data_dir(void);
 
+struct android_app *lo_get_app(void);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/sal/inc/osl/detail/android_native_app_glue.h b/sal/inc/osl/detail/android_native_app_glue.h
new file mode 100644
index 000000000000..862ca9e990f8
--- /dev/null
+++ b/sal/inc/osl/detail/android_native_app_glue.h
@@ -0,0 +1,351 @@
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Copyright (C) 2010 The Android Open Source Project
+ *
+ *   Licensed under the Apache License, Version 2.0 (the "License");
+ *   you may not use this file except in compliance with the License.
+ *   You may obtain a copy of the License at
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ */
+
+#ifndef _ANDROID_NATIVE_APP_GLUE_H
+#define _ANDROID_NATIVE_APP_GLUE_H
+#if defined(ANDROID)
+
+#include <poll.h>
+#include <pthread.h>
+#include <sched.h>
+
+#include <android/configuration.h>
+#include <android/looper.h>
+#include <android/native_activity.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * The native activity interface provided by <android/native_activity.h>
+ * is based on a set of application-provided callbacks that will be called
+ * by the Activity's main thread when certain events occur.
+ *
+ * This means that each one of this callbacks _should_ _not_ block, or they
+ * risk having the system force-close the application. This programming
+ * model is direct, lightweight, but constraining.
+ *
+ * The 'threaded_native_app' static library is used to provide a different
+ * execution model where the application can implement its own main event
+ * loop in a different thread instead. Here's how it works:
+ *
+ * 1/ The application must provide a function named "android_main()" that
+ *    will be called when the activity is created, in a new thread that is
+ *    distinct from the activity's main thread.
+ *
+ * 2/ android_main() receives a pointer to a valid "android_app" structure
+ *    that contains references to other important objects, e.g. the
+ *    ANativeActivity obejct instance the application is running in.
+ *
+ * 3/ the "android_app" object holds an ALooper instance that already
+ *    listens to two important things:
+ *
+ *      - activity lifecycle events (e.g. "pause", "resume"). See APP_CMD_XXX
+ *        declarations below.
+ *
+ *      - input events coming from the AInputQueue attached to the activity.
+ *
+ *    Each of these correspond to an ALooper identifier returned by
+ *    ALooper_pollOnce with values of LOOPER_ID_MAIN and LOOPER_ID_INPUT,
+ *    respectively.
+ *
+ *    Your application can use the same ALooper to listen to additional
+ *    file-descriptors.  They can either be callback based, or with return
+ *    identifiers starting with LOOPER_ID_USER.
+ *
+ * 4/ Whenever you receive a LOOPER_ID_MAIN or LOOPER_ID_INPUT event,
+ *    the returned data will point to an android_poll_source structure.  You
+ *    can call the process() function on it, and fill in android_app->onAppCmd
+ *    and android_app->onInputEvent to be called for your own processing
+ *    of the event.
+ *
+ *    Alternatively, you can call the low-level functions to read and process
+ *    the data directly...  look at the process_cmd() and process_input()
+ *    implementations in the glue to see how to do this.
+ *
+ * See the sample named "native-activity" that comes with the NDK with a
+ * full usage example.  Also look at the JavaDoc of NativeActivity.
+ */
+
+struct android_app;
+
+/**
+ * Data associated with an ALooper fd that will be returned as the "outData"
+ * when that source has data ready.
+ */
+struct android_poll_source {
+    // The identifier of this source.  May be LOOPER_ID_MAIN or
+    // LOOPER_ID_INPUT.
+    int32_t id;
+
+    // The android_app this ident is associated with.
+    struct android_app* app;
+
+    // Function to call to perform the standard processing of data from
+    // this source.
+    void (*process)(struct android_app* app, struct android_poll_source* source);
+};
+
+/**
+ * This is the interface for the standard glue code of a threaded
+ * application.  In this model, the application's code is running
+ * in its own thread separate from the main thread of the process.
+ * It is not required that this thread be associated with the Java
+ * VM, although it will need to be in order to make JNI calls any
+ * Java objects.
+ */
+struct android_app {
+    // The application can place a pointer to its own state object
+    // here if it likes.
+    void* userData;
+
+    // Fill this in with the function to process main app commands (APP_CMD_*)
+    void (*onAppCmd)(struct android_app* app, int32_t cmd);
+
+    // Fill this in with the function to process input events.  At this point
+    // the event has already been pre-dispatched, and it will be finished upon
+    // return.  Return 1 if you have handled the event, 0 for any default
+    // dispatching.
+    int32_t (*onInputEvent)(struct android_app* app, AInputEvent* event);
+
+    // The ANativeActivity object instance that this app is running in.
+    ANativeActivity* activity;
+
+    // The current configuration the app is running in.
+    AConfiguration* config;
+
+    // This is the last instance's saved state, as provided at creation time.
+    // It is NULL if there was no state.  You can use this as you need; the
+    // memory will remain around until you call android_app_exec_cmd() for
+    // APP_CMD_RESUME, at which point it will be freed and savedState set to NULL.
+    // These variables should only be changed when processing a APP_CMD_SAVE_STATE,
+    // at which point they will be initialized to NULL and you can malloc your
+    // state and place the information here.  In that case the memory will be
+    // freed for you later.
+    void* savedState;
+    size_t savedStateSize;
+
+    // The ALooper associated with the app's thread.
+    ALooper* looper;
+
+    // When non-NULL, this is the input queue from which the app will
+    // receive user input events.
+    AInputQueue* inputQueue;
+
+    // When non-NULL, this is the window surface that the app can draw in.
+    ANativeWindow* window;
+
+    // Current content rectangle of the window; this is the area where the
+    // window's content should be placed to be seen by the user.
+    ARect contentRect;
+
+    // Current state of the app's activity.  May be either APP_CMD_START,
+    // APP_CMD_RESUME, APP_CMD_PAUSE, or APP_CMD_STOP; see below.
+    int activityState;
+
+    // This is non-zero when the application's NativeActivity is being
+    // destroyed and waiting for the app thread to complete.
+    int destroyRequested;
+
+    // -------------------------------------------------
+    // Below are "private" implementation of the glue code.
+
+    pthread_mutex_t mutex;
+    pthread_cond_t cond;
+
+    int msgread;
+    int msgwrite;
+
+    pthread_t thread;
+
+    struct android_poll_source cmdPollSource;
+    struct android_poll_source inputPollSource;
+
+    int running;
+    int stateSaved;
+    int destroyed;
+    int redrawNeeded;
+    AInputQueue* pendingInputQueue;
+    ANativeWindow* pendingWindow;
+    ARect pendingContentRect;
+};
+
+enum {
+    /**
+     * Looper data ID of commands coming from the app's main thread, which
+     * is returned as an identifier from ALooper_pollOnce().  The data for this
+     * identifier is a pointer to an android_poll_source structure.
+     * These can be retrieved and processed with android_app_read_cmd()
+     * and android_app_exec_cmd().
+     */
+    LOOPER_ID_MAIN = 1,
+
+    /**
+     * Looper data ID of events coming from the AInputQueue of the
+     * application's window, which is returned as an identifier from
+     * ALooper_pollOnce().  The data for this identifier is a pointer to an
+     * android_poll_source structure.  These can be read via the inputQueue
+     * object of android_app.
+     */
+    LOOPER_ID_INPUT = 2,
+
+    /**
+     * Start of user-defined ALooper identifiers.
+     */
+    LOOPER_ID_USER = 3,
+};
+
+enum {
+    /**
+     * Command from main thread: the AInputQueue has changed.  Upon processing
+     * this command, android_app->inputQueue will be updated to the new queue
+     * (or NULL).
+     */
+    APP_CMD_INPUT_CHANGED,
+
+    /**
+     * Command from main thread: a new ANativeWindow is ready for use.  Upon
+     * receiving this command, android_app->window will contain the new window
+     * surface.
+     */
+    APP_CMD_INIT_WINDOW,
+
+    /**
+     * Command from main thread: the existing ANativeWindow needs to be
+     * terminated.  Upon receiving this command, android_app->window still
+     * contains the existing window; after calling android_app_exec_cmd
+     * it will be set to NULL.
+     */
+    APP_CMD_TERM_WINDOW,
+
+    /**
+     * Command from main thread: the current ANativeWindow has been resized.
+     * Please redraw with its new size.
+     */
+    APP_CMD_WINDOW_RESIZED,
+
+    /**
+     * Command from main thread: the system needs that the current ANativeWindow
+     * be redrawn.  You should redraw the window before handing this to
+     * android_app_exec_cmd() in order to avoid transient drawing glitches.
+     */
+    APP_CMD_WINDOW_REDRAW_NEEDED,
+
+    /**
+     * Command from main thread: the content area of the window has changed,
+     * such as from the soft input window being shown or hidden.  You can
+     * find the new content rect in android_app::contentRect.
+     */
+    APP_CMD_CONTENT_RECT_CHANGED,
+
+    /**
+     * Command from main thread: the app's activity window has gained
+     * input focus.
+     */
+    APP_CMD_GAINED_FOCUS,
+
+    /**
+     * Command from main thread: the app's activity window has lost
+     * input focus.
+     */
+    APP_CMD_LOST_FOCUS,
+
+    /**
+     * Command from main thread: the current device configuration has changed.
+     */
+    APP_CMD_CONFIG_CHANGED,
+
+    /**
+     * Command from main thread: the system is running low on memory.
+     * Try to reduce your memory use.
+     */
+    APP_CMD_LOW_MEMORY,
+
+    /**
+     * Command from main thread: the app's activity has been started.
+     */
+    APP_CMD_START,
+
+    /**
+     * Command from main thread: the app's activity has been resumed.
+     */
+    APP_CMD_RESUME,
+
+    /**
+     * Command from main thread: the app should generate a new saved state
+     * for itself, to restore from later if needed.  If you have saved state,
+     * allocate it with malloc and place it in android_app.savedState with
+     * the size in android_app.savedStateSize.  The will be freed for you
+     * later.
+     */
+    APP_CMD_SAVE_STATE,
+
+    /**
+     * Command from main thread: the app's activity has been paused.
+     */
+    APP_CMD_PAUSE,
+
+    /**
+     * Command from main thread: the app's activity has been stopped.
+     */
+    APP_CMD_STOP,
+
+    /**
+     * Command from main thread: the app's activity is being destroyed,
+     * and waiting for the app thread to clean up and exit before proceeding.
+     */
+    APP_CMD_DESTROY,
+};
+
+/**
+ * Call when ALooper_pollAll() returns LOOPER_ID_MAIN, reading the next
+ * app command message.
+ */
+int8_t android_app_read_cmd(struct android_app* android_app);
+
+/**
+ * Call with the command returned by android_app_read_cmd() to do the
+ * initial pre-processing of the given command.  You can perform your own
+ * actions for the command after calling this function.
+ */
+void android_app_pre_exec_cmd(struct android_app* android_app, int8_t cmd);
+
+/**
+ * Call with the command returned by android_app_read_cmd() to do the
+ * final post-processing of the given command.  You must have done your own
+ * actions for the command before calling this function.
+ */
+void android_app_post_exec_cmd(struct android_app* android_app, int8_t cmd);
+
+/**
+ * Dummy function you can call to ensure glue code isn't stripped.
+ */
+void app_dummy();
+
+/**
+ * This is the function that application code must implement, representing
+ * the main entry to the app.
+ */
+extern void android_main(struct android_app* app);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // ANDROID
+#endif /* _ANDROID_NATIVE_APP_GLUE_H */
diff --git a/sal/inc/sal/main.h b/sal/inc/sal/main.h
index 8648e38752ab..7cdc9bc62c0c 100644
--- a/sal/inc/sal/main.h
+++ b/sal/inc/sal/main.h
@@ -38,7 +38,25 @@ SAL_DLLPUBLIC void SAL_CALL sal_detail_deinitialize();
 
 #if defined IOS || defined ANDROID
 
-#error No code that includes this should be built for iOS or Android
+#ifdef __cplusplus
+extern "C" SAL_DLLPUBLIC_EXPORT void lo_main(int argc, char **argv);
+#endif
+
+#define SAL_MAIN_WITH_ARGS_IMPL \
+SAL_DLLPUBLIC_EXPORT void lo_main(int argc, char **argv) \
+{ \
+    sal_detail_initialize(argc, argv); \
+    sal_main_with_args(argc, argv); \
+    sal_detail_deinitialize(); \
+}
+
+#define SAL_MAIN_IMPL \
+SAL_DLLPUBLIC_EXPORT void lo_main(int argc, char **argv) \
+{ \
+    sal_detail_initialize(argc, argv); \
+    sal_main(); \
+    sal_detail_deinitialize(); \
+}
 
 #else
 
diff --git a/sal/osl/unx/process_impl.cxx b/sal/osl/unx/process_impl.cxx
index 723d10bcd436..4a10af514557 100644
--- a/sal/osl/unx/process_impl.cxx
+++ b/sal/osl/unx/process_impl.cxx
@@ -104,10 +104,26 @@ oslProcessError SAL_CALL osl_bootstrap_getExecutableFile_Impl (
 {
     oslProcessError result = osl_Process_E_NotFound;
 
-#ifdef ANDROID
-    /* Now with just a single DSO, this one from lo-bootstrap.c is as good as
-     * any */
-    void * addr = dlsym (RTLD_DEFAULT, "JNI_OnLoad");
+#if defined(ANDROID) && !defined(DISABLE_DYNLOADING)
+    /* On Android we in theory want the address of the "lo_main()"
+     * function, as that is what corresponds to "main()" in
+     * LibreOffice programs on normal desktop OSes.
+     *
+     * But that is true only for apps with a "native activity", using
+     * <sal/main.h> and the org.libreoffice.android.Bootstrap
+     * mechanism. For more normal (?) Android apps that just use
+     * LibreOffice libraries (components) where the main program is in
+     * Java, that just use LibreOffice libraries, there is no
+     * lo_main(). (Note that we don't know for sure yet how
+     * complicated it might be to write such Android apps...)
+     *
+     * Maybe best to just pick some function in liblo-bootstrap.so
+     * which also such Java apps *must* load as the very first
+     * LibreOffice native library. We store all LibreOffice native
+     * shared libraries an app uses in the same folder anyway, so it
+     * doesn't really matter.
+     */
+    void * addr = (void *) &lo_dlopen;
 #else
     /* Determine address of "main()" function. */
     void * addr = dlsym (RTLD_DEFAULT, "main");