Add android_native_app_glue.[hc} from the NDK

Simplest for now to have a copy of them in our sources. Improve later.

solenv/unxandr/inc/android_native_app_glue.c

+/*
+ * 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
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <jni.h>
+
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/resource.h>
+
+#include "android_native_app_glue.h"
+#include <android/log.h>
+
+#define LOGI(...) ((void)__android_log_print(ANDROID_LOG_INFO, "threaded_app", __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_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_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 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);
+}
+
+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->onInputQueueCreated = onInputQueueCreated;
+    activity->callbacks->onInputQueueDestroyed = onInputQueueDestroyed;
+
+    activity->instance = android_app_create(activity, savedState, savedStateSize);
+}

solenv/unxandr/inc/android_native_app_glue.h

+/*
+ * 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
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef _ANDROID_NATIVE_APP_GLUE_H
+#define _ANDROID_NATIVE_APP_GLUE_H
+
+#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_NATIVE_APP_GLUE_H */