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

3 files changed, 372 insertions, 1 deletions

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