Bring up the Android operating system and its window system

* .dir-locals.el (c-mode): Add ANDROID_EXPORT noise macro.
* .gitignore: Add new files to ignore.
* Makefile.in: Adjust for Android.
* admin/merge-gnulib: Add new warning.
* configure.ac: Detect Android.  Run cross-configuration for
Android when appropriate.

* etc/DEBUG: Document how to debug Emacs on Android.

* java/AndroidManifest.xml:
* java/Makefile.in:
* java/README:
* java/debug.sh:
* java/org/gnu/emacs/EmacsActivity.java (EmacsActivity):
* java/org/gnu/emacs/EmacsApplication.java (EmacsApplication):
* java/org/gnu/emacs/EmacsCopyArea.java (EmacsCopyArea):
* java/org/gnu/emacs/EmacsDrawLine.java (EmacsDrawLine):
* java/org/gnu/emacs/EmacsDrawPoint.java (EmacsDrawPoint):
* java/org/gnu/emacs/EmacsDrawRectangle.java
(EmacsDrawRectangle):
* java/org/gnu/emacs/EmacsDrawable.java (EmacsDrawable):
* java/org/gnu/emacs/EmacsFillPolygon.java (EmacsFillPolygon):
* java/org/gnu/emacs/EmacsFillRectangle.java
(EmacsFillRectangle):
* java/org/gnu/emacs/EmacsFontDriver.java (EmacsFontDriver):
* java/org/gnu/emacs/EmacsGC.java (EmacsGC):
* java/org/gnu/emacs/EmacsHandleObject.java (EmacsHandleObject):
* java/org/gnu/emacs/EmacsNative.java (EmacsNative):
* java/org/gnu/emacs/EmacsPaintQueue.java (EmacsPaintQueue):
* java/org/gnu/emacs/EmacsPaintReq.java (EmacsPaintReq):
* java/org/gnu/emacs/EmacsPixmap.java (EmacsPixmap):
* java/org/gnu/emacs/EmacsSdk7FontDriver.java
(EmacsSdk7FontDriver):
* java/org/gnu/emacs/EmacsService.java (class Holder<T>)
(EmacsService):
* java/org/gnu/emacs/EmacsSurfaceView.java (EmacsSurfaceView):
* java/org/gnu/emacs/EmacsThread.java (EmacsThread):
* java/org/gnu/emacs/EmacsView.java (EmacsView):
* java/org/gnu/emacs/EmacsWindow.java (EmacsWindow): New files
and classes.

* lib-src/Makefile.in (srcdir):
* lib/Makefile.in (VPATH):
(HAVE_NATIVE_COMP):
(libgnu_a_SOURCES):
(DEPFLAGS): Configure correctly for cross-compiling.

* lib/faccessat.c:
* lib/fpending.c (__fpending):
* lib/open.c:
* lib/unistd.c (_GL_UNISTD_INLINE): Temporary adjustments to
gnulib.

* lisp/frame.el (display-graphic-p):
(display-screens):
(display-pixel-height):
(display-pixel-width):
(display-mm-height):
(display-mm-width):
(display-backing-store):
(display-save-under):
(display-planes):
(display-color-cells):
(display-visual-class): Adjust for new window system `android'.

* lisp/image/wallpaper.el (x-open-connection): Add declaration.
* lisp/loadup.el (featurep): Load up files for Android.
* lisp/net/eww.el (eww-form-submit, eww-form-file)
(eww-form-checkbox, eww-form-select): Adjust faces for android.
* lisp/term/android-win.el: New file.
* src/Makefile.in: Add new targets emacs.so and android-emacs,
then adjust for cross compilation.
* src/alloc.c (cleanup_vector): Clean up Android font entities
as well.
(garbage_collect): Mark androidterm.
* src/android-emacs.c (main):
* src/android.c (ANDROID_THROW, enum android_fd_table_entry_flags)
(struct android_emacs_service, struct android_emacs_pixmap)
(struct android_graphics_point, struct android_event_container)
(struct android_event_queue, android_run_select_thread)
(android_handle_sigusr1, android_init_events, android_pending)
(android_next_event, android_write_event, android_select)
(android_run_debug_thread, android_user_full_name)
(android_get_asset_name, android_fstat, android_fstatat)
(android_file_access_p, android_hack_asset_fd, android_open)
(android_close, JNICALL, android_init_emacs_service)
(android_init_emacs_pixmap, android_init_graphics_point)
(MAX_HANDLE, struct android_handle_entry, android_alloc_id)
(android_destroy_handle, android_resolve_handle)
(android_resolve_handle2, android_change_window_attributes)
(android_create_window, android_set_window_background)
(android_destroy_window, android_init_android_rect_class)
(android_init_emacs_gc_class, android_create_gc, android_free_gc)
(android_change_gc, android_set_clip_rectangles)
(android_reparent_window, android_lookup_method)
(android_clear_window, android_map_window, android_unmap_window)
(android_resize_window, android_move_window, android_swap_buffers)
(android_get_gc_values, android_set_foreground)
(android_fill_rectangle, android_create_pixmap_from_bitmap_data)
(android_set_clip_mask, android_set_fill_style, android_copy_area)
(android_free_pixmap, android_set_background, android_fill_polygon)
(android_draw_rectangle, android_draw_point, android_draw_line)
(android_create_pixmap, android_set_ts_origin, android_clear_area):
* src/android.h (ANDROID_EXPORT):
* src/androidfns.c (android_display_info_for_name)
(check_android_display_info, check_x_display_info, gamma_correct)
(android_defined_color, android_decode_color)
(android_implicitly_set_name, android_explicitly_set_name)
(android_set_tool_bar_lines, android_change_tool_bar_height)
(android_set_tab_bar_lines, android_change_tab_bar_height)
(android_set_scroll_bar_default_height)
(android_set_scroll_bar_default_width, android_icon_verify)
(android_icon, android_make_gc, android_free_gcs)
(unwind_create_frame, do_unwind_create_frame)
(android_default_font_parameter, android_create_frame_window)
(Fx_create_frame, Fxw_color_defined_p, Fxw_color_values)
(Fxw_display_color_p, Fx_display_grayscale_p)
(Fx_display_pixel_width, Fx_display_pixel_height)
(Fx_display_planes, Fx_display_color_cells, Fx_display_screens)
(Fx_display_mm_width, Fx_display_mm_height)
(Fx_display_backing_store, Fx_display_visual_class)
(Fx_display_monitor_attributes_list, Fx_frame_geometry)
(Fx_frame_list_z_order, Fx_frame_restack)
(Fx_mouse_absolute_pixel_position)
(Fx_set_mouse_absolute_pixel_position, Fandroid_get_connection)
(Fx_display_list, Fx_show_tip, Fx_hide_tip)
(android_set_background_color, android_set_border_color)
(android_set_cursor_color, android_set_cursor_type)
(android_set_foreground_color)
(android_set_child_frame_border_width)
(android_set_internal_border_width, android_set_menu_bar_lines)
(android_set_mouse_color, android_set_title, android_set_alpha)
(android_frame_parm_handlers, syms_of_androidfns):
* src/androidfont.c (struct android_emacs_font_driver)
(struct android_emacs_font_spec, struct android_emacs_font_metrics)
(struct android_emacs_font_object, struct android_integer)
(struct androidfont_info, struct androidfont_entity)
(android_init_font_driver, android_init_font_spec)
(android_init_font_metrics, android_init_integer)
(android_init_font_object, androidfont_get_cache)
(androidfont_from_lisp, androidfont_from_java, androidfont_list)
(androidfont_match, androidfont_draw, androidfont_open_font)
(androidfont_close_font, androidfont_has_char)
(androidfont_encode_char, androidfont_text_extents)
(androidfont_list_family, androidfont_driver)
(syms_of_androidfont_for_pdumper, syms_of_androidfont)
(init_androidfont, android_finalize_font_entity):
* src/androidgui.h (_ANDROID_GUI_H_, struct android_rectangle)
(struct android_point, enum android_gc_function)
(enum android_gc_value_mask, enum android_fill_style)
(enum android_window_value_mask)
(struct android_set_window_attributes, struct android_gc_values)
(struct android_gc, enum android_swap_action, enum android_shape)
(enum android_coord_mode, struct android_swap_info)
(NativeRectangle, struct android_any_event)
(struct android_key_event, struct android_configure_event)
(union android_event):
* src/androidterm.c (android_window_to_frame, android_clear_frame)
(android_ring_bell, android_toggle_invisible_pointer)
(android_update_begin, android_update_end, show_back_buffer)
(android_flush_dirty_back_buffer_on, handle_one_android_event)
(android_read_socket, android_frame_up_to_date)
(android_buffer_flipping_unblocked_hook)
(android_query_frame_background_color, android_parse_color)
(android_alloc_nearest_color, android_query_colors)
(android_mouse_position, android_get_focus_frame)
(android_focus_frame, android_frame_rehighlight)
(android_frame_raise_lower, android_make_frame_visible)
(android_make_frame_invisible)
(android_make_frame_visible_invisible, android_fullscreen_hook)
(android_iconify_frame, android_set_window_size_1)
(android_set_window_size, android_set_offset, android_set_alpha)
(android_new_font, android_bitmap_icon, android_free_pixmap_hook)
(android_free_frame_resources, android_delete_frame)
(android_delete_terminal, android_scroll_run)
(android_after_update_window_line, android_flip_and_flush)
(android_clear_rectangle, android_reset_clip_rectangles)
(android_clip_to_row, android_draw_fringe_bitmap)
(android_set_cursor_gc, android_set_mouse_face_gc)
(android_set_mode_line_face_gc, android_set_glyph_string_gc)
(android_set_glyph_string_clipping)
(android_set_glyph_string_clipping_exactly)
(android_compute_glyph_string_overhangs)
(android_clear_glyph_string_rect)
(android_draw_glyph_string_background, android_fill_triangle)
(android_make_point, android_inside_rect_p, android_clear_point)
(android_draw_relief_rect, android_draw_box_rect)
(HIGHLIGHT_COLOR_DARK_BOOST_LIMIT, android_setup_relief_color)
(android_setup_relief_colors, android_draw_glyph_string_box)
(android_draw_glyph_string_bg_rect, android_draw_image_relief)
(android_draw_image_foreground, android_draw_image_foreground_1)
(android_draw_image_glyph_string)
(android_draw_stretch_glyph_string, android_draw_underwave)
(android_draw_glyph_string_foreground)
(android_draw_composite_glyph_string_foreground)
(android_draw_glyphless_glyph_string_foreground)
(android_draw_glyph_string, android_define_frame_cursor)
(android_clear_frame_area, android_clear_under_internal_border)
(android_draw_hollow_cursor, android_draw_bar_cursor)
(android_draw_window_cursor, android_draw_vertical_window_border)
(android_draw_window_divider, android_redisplay_interface)
(frame_set_mouse_pixel_position, get_keysym_name)
(android_create_terminal, android_term_init, syms_of_androidterm)
(mark_androidterm):
* src/androidterm.h (_ANDROID_TERM_H_, struct android_display_info)
(struct android_output, FRAME_ANDROID_OUTPUT, XSCROLL_BAR): New
files.
* src/dired.c (file_attributes): Do not use openat on Android.
* src/dispextern.h (No_Cursor): Define appropriately on Android.
(struct glyph_string, struct face): Make gc field of type struct
android_gc on Android.
* src/dispnew.c (clear_current_matrices, clear_desired_matrices)
(adjust_frame_glyphs_for_window_redisplay, free_glyphs)
(update_frame, scrolling, char_ins_del_cost, update_frame_line)
(init_display_interactive): Disable text terminal support
completely on Android.  Fix non-toolkit menus for non-X systems.
* src/editfns.c (Fuser_full_name): Call android_user_full_name.
* src/emacs.c (android_emacs_init): Make main this on Android.
Prohibit argv sorting from exceeding end of argv.
* src/epaths.in: Add path definitions for Android.

* src/fileio.c (file_access_p): Call android_file_access_p.
(file_name_directory): Avoid using openat on Android.
(Fcopy_file): Adjust to call sys_fstat instead.
(file_directory_p):
(Finsert_file_contents):
(write_region): Likewise.
* src/filelock.c:
* src/fns.c (Flocale_info): Pacify warning on Android.
* src/font.c (font_make_entity_android): New function.
* src/font.h:
* src/frame.c (Fframep):
(Fwindow_system): Handle new window system `android'.  Update doc strings.
(Fmake_terminal_frame): Disable on Android.
(gui_display_get_resource): Disable get_string_resource_hook on Android.
(syms_of_frame): New defsym `android'.

* src/frame.h (GCALIGNED_STRUCT): Add new output data for
Android.
(ENUM_BF): Expand enumerator size.
(FRAME_ANDROID_P, FRAME_WINDOW_P, MOUSE_HL_INFO): Add
definitions for Android.

* src/image.c (GET_PIXEL):
(image_create_bitmap_from_file):
(image_create_x_image_and_pixmap_1):
(image_get_x_image):
(slurp_file):
(lookup_rgb_color):
(image_to_emacs_colors):
(image_from_emacs_colors):
(image_pixmap_draw_cross):
(image_disable_image):
(MaskForeground):
(gif_load): Add stubs for Android.

* src/lisp.h:
* src/lread.c (safe_to_load_version, maybe_swap_for_eln1, openp):
* src/pdumper.c (pdumper_load): Call sys_fstat instead of fstat.
* src/process.c (wait_reading_process_output): Use
android_select instead of pselect.
* src/scroll.c: Disable on Android.
* src/sysdep.c (widen_foreground_group, reset_sys_modes)
(init_signals, emacs_fstatat, sys_fstat): New function.
(emacs_open, emacs_open_noquit, emacs_close): Implement
differently on Android.
(close_output_streams): Disable what is not required on Android.

* src/term.c (OUTPUT1_IF, encode_terminal_code, string_cost)
(string_cost_one_line, per_line_cost, calculate_costs)
(struct fkey_table, tty_append_glyph, produce_glyphs)
(tty_capable_p, Fsuspend_tty, Fresume_tty, device, init_tty)
(maybe_fatal, syms_of_term): Disable text terminal support on
Android.

* src/termhooks.h (enum output_method): Add android output
method.
(GCALIGNED_STRUCT, TERMINAL_FONT_CACHE): Define for Android.

* src/terminal.c (Fterminal_live_p): Implement for Android.

* src/verbose.mk.in (AM_V_GLOBALS): Add JAVAC and DX.
* src/xdisp.c (redisplay_internal): Disable text terminals on Android.
(display_menu_bar):
(display_tty_menu_item):
(draw_row_with_mouse_face):
(expose_frame): Make the non toolkit menu bar work on Android.

* src/xfaces.c (GCGraphicsExposures):
(x_create_gc):
(x_free_gc):
(Fx_load_color_file): Define for Android.

* xcompile/Makefile.in (top_srcdir):
(top_builddir):
* xcompile/README:
* xcompile/langinfo.h (nl_langinfo): New files.

java/org/gnu/emacs/EmacsWindow.java

@@ -0,0 +1,336 @@
+/* Communication module for Android terminals.  -*- c-file-style: "GNU" -*-
+
+Copyright (C) 2023 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
+
+package org.gnu.emacs;
+
+import java.lang.IllegalStateException;
+import java.util.ArrayList;
+import java.util.List;
+
+import android.graphics.Rect;
+import android.graphics.Canvas;
+import android.graphics.Bitmap;
+import android.graphics.Point;
+
+import android.view.View;
+import android.view.ViewGroup;
+import android.view.KeyEvent;
+
+/* This defines a window, which is a handle.  Windows represent a
+   rectangular subset of the screen with their own contents.
+
+   Windows either have a parent window, in which case their views are
+   attached to the parent's view, or are "floating", in which case
+   their views are attached to the parent activity (if any), else
+   nothing.
+
+   Views are also drawables, meaning they can accept drawing
+   requests.  */
+
+public class EmacsWindow extends EmacsHandleObject
+  implements EmacsDrawable
+{
+  /* The view associated with the window.  */
+  public EmacsView view;
+
+  /* The geometry of the window.  */
+  private Rect rect;
+
+  /* The parent window, or null if it is the root window.  */
+  private EmacsWindow parent;
+
+  /* List of all children in stacking order.  This must be kept
+     consistent!  */
+  private ArrayList<EmacsWindow> children;
+
+  /* The EmacsActivity currently attached, if it exists.  */
+  private EmacsActivity attached;
+
+  /* The window background scratch GC.  foreground is always the
+     window background.  */
+  private EmacsGC scratchGC;
+
+  public
+  EmacsWindow (short handle, final EmacsWindow parent, int x, int y,
+	       int width, int height)
+  {
+    super (handle);
+
+    rect = new Rect (x, y, x + width, y + height);
+
+    /* Create the view from the context's UI thread.  */
+    view = EmacsService.SERVICE.getEmacsView (this);
+    this.parent = parent;
+    children = new ArrayList<EmacsWindow> ();
+
+    /* The window is unmapped by default.  */
+    view.setVisibility (View.GONE);
+
+    /* If parent is the root window, notice that there are new
+       children available for interested activites to pick up.  */
+    if (parent == null)
+      EmacsService.SERVICE.noticeAvailableChild (this);
+    else
+      {
+	/* Otherwise, directly add this window as a child of that
+	   window's view.  */
+	synchronized (parent)
+	  {
+	    parent.children.add (this);
+	    parent.view.post (new Runnable () {
+		@Override
+		public void
+		run ()
+		{
+		  parent.view.addView (view);
+		}
+	      });
+	  }
+      }
+
+    scratchGC = new EmacsGC ((short) 0);
+  }
+
+  public void
+  changeWindowBackground (int pixel)
+  {
+    /* scratchGC is used as the argument to a FillRectangles req.  */
+    scratchGC.foreground = pixel;
+    scratchGC.markDirty ();
+  }
+
+  public Rect
+  getGeometry ()
+  {
+    synchronized (this)
+      {
+	/* Huh, this is it.  */
+	return rect;
+      }
+  }
+
+  @Override
+  public void
+  destroyHandle () throws IllegalStateException
+  {
+    synchronized (this)
+      {
+	if (!children.isEmpty ())
+	  throw new IllegalStateException ("Trying to destroy window with "
+					   + "children!");
+      }
+
+    /* Notice that the child has been destroyed.  */
+    EmacsService.SERVICE.noticeChildDestroyed (this);
+
+    /* Remove the view from its parent and make it invisible.  */
+    view.post (new Runnable () {
+	public void
+	run ()
+	{
+	  view.setVisibility (View.GONE);
+
+	  if (view.getParent () != null)
+	    ((ViewGroup) view.getParent ()).removeView (view);
+
+	  if (attached != null)
+	    attached.makeAvailable ();
+	}
+      });
+
+    super.destroyHandle ();
+  }
+
+  public void
+  setActivity (EmacsActivity activity)
+  {
+    synchronized (this)
+      {
+	activity = activity;
+      }
+  }
+
+  public void
+  viewLayout (int left, int top, int right, int bottom)
+  {
+    synchronized (this)
+      {
+	rect.left = left;
+	rect.top = top;
+	rect.right = right;
+	rect.bottom = bottom;
+
+	EmacsNative.sendConfigureNotify (this.handle,
+					 System.currentTimeMillis (),
+					 left, top, rect.width (),
+					 rect.height ());
+      }
+  }
+
+  public void
+  requestViewLayout ()
+  {
+    view.post (new Runnable () {
+	@Override
+	public void
+	run ()
+	{
+	  view.requestLayout ();
+	}
+      });
+  }
+
+  public void
+  resizeWindow (int width, int height)
+  {
+    synchronized (this)
+      {
+	rect.right = rect.left + width;
+	rect.bottom = rect.top + height;
+      }
+  }
+
+  public void
+  moveWindow (int x, int y)
+  {
+    int width, height;
+
+    synchronized (this)
+      {
+	width = rect.width ();
+	height = rect.height ();
+
+	rect.left = x;
+	rect.top = y;
+	rect.right = x + width;
+	rect.bottom = y + height;
+
+	requestViewLayout ();
+      }
+  }
+
+  public void
+  mapWindow ()
+  {
+    view.post (new Runnable () {
+	@Override
+	public void
+	run ()
+	{
+	  view.setVisibility (View.VISIBLE);
+	}
+      });
+  }
+
+  public void
+  unmapWindow ()
+  {
+    view.post (new Runnable () {
+	@Override
+	public void
+	run ()
+	{
+	  view.setVisibility (View.GONE);
+	}
+      });
+  }
+
+  @Override
+  public Canvas
+  lockCanvas ()
+  {
+    if (view.canvas != null)
+      return view.canvas;
+
+    return null;
+  }
+
+  @Override
+  public void
+  unlockCanvas ()
+  {
+
+  }
+
+  @Override
+  public void
+  damageRect (Rect damageRect)
+  {
+    view.damageRect (damageRect);
+  }
+
+  public void
+  swapBuffers ()
+  {
+    /* Before calling swapBuffers, make sure to flush the paint
+       queue.  */
+    EmacsService.SERVICE.flushPaintQueue ();
+    view.post (new Runnable () {
+	@Override
+	public void
+	run ()
+	{
+	  view.swapBuffers ();
+	}
+      });
+  }
+
+  public void
+  clearWindow ()
+  {
+    synchronized (this)
+      {
+	EmacsService.SERVICE.fillRectangle (this, scratchGC,
+					    0, 0, rect.width (),
+					    rect.height ());
+      }
+  }
+
+  public void
+  clearArea (int x, int y, int width, int height)
+  {
+    EmacsService.SERVICE.fillRectangle (this, scratchGC,
+					x, y, width, height);
+  }
+
+  @Override
+  public Bitmap
+  getBitmap ()
+  {
+    return view.bitmap;
+  }
+
+  public void
+  onKeyDown (int keyCode, KeyEvent event)
+  {
+    EmacsNative.sendKeyPress (this.handle,
+			      event.getEventTime (),
+			      event.getModifiers (),
+			      keyCode);
+  }
+
+  public void
+  onKeyUp (int keyCode, KeyEvent event)
+  {
+    EmacsNative.sendKeyRelease (this.handle,
+				event.getEventTime (),
+				event.getModifiers (),
+				keyCode);
+  }
+};