Update Android port

* doc/emacs/android.texi (Android Startup, Android Environment):
Document that restrictions on starting Emacs have been lifted.

* java/README: Document Java for Emacs developers and how the
Android port works.

* java/org/gnu/emacs/EmacsApplication.java (EmacsApplication)
(findDumpFile): New function.
(onCreate): Factor out dump file finding functions to there.

* java/org/gnu/emacs/EmacsNative.java (EmacsNative): Update
function declarations.
* java/org/gnu/emacs/EmacsNoninteractive.java
(EmacsNoninteractive): New class.

* java/org/gnu/emacs/EmacsService.java (EmacsService, getApkFile)
(onCreate): Pass classpath to setEmacsParams.
* java/org/gnu/emacs/EmacsThread.java (EmacsThread): Make run an
override.
* lisp/loadup.el: Don't dump on Android when noninteractive.
* lisp/shell.el (shell--command-completion-data): Handle
inaccessible directories.
* src/Makefile.in (android-emacs): Link with gnulib.
* src/android-emacs.c (main): Implement to launch app-process
and then EmacsNoninteractive.
* src/android.c (setEmacsParams): New argument `class_path'.
Don't set stuff up when running noninteractive.
* src/android.h (initEmacs): Likewise.
* src/androidfont.c (init_androidfont):
* src/androidselect.c (init_androidselect): Don't initialize
when running noninteractive.
* src/emacs.c (load_pdump): New argument `dump_file'.
(android_emacs_init): Give new argument `dump_file' to
`load_pdump'.
* src/sfntfont-android.c (init_sfntfont_android): Don't
initialize when running noninteractive.

1 files changed, 79 insertions, 4 deletions

diff --git a/src/android-emacs.c b/src/android-emacs.c
index d4fa14e39fb..c1f2a6f43bb 100644
--- a/src/android-emacs.c
+++ b/src/android-emacs.c
@@ -18,13 +18,88 @@ You should have received a copy of the GNU General Public License
 along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 
 #include <config.h>
-#include "android.h"
+#include <stdio.h>
+#include <alloca.h>
+#include <string.h>
+#include <unistd.h>
 
-/* android-emacs is a wrapper around libemacs.  It simply calls
-   android_emacs_init with the argv and argc given to it.  */
+/* android-emacs is a wrapper around /system/bin/app_process(64).
+   It invokes app_process(64) with the right class path and then
+   starts org.gnu.emacs.EmacsNoninteractive.
+
+   The main function in that class tries to load an activity thread
+   and obtain a context and asset manager before calling
+   android_emacs_init, which is required for Emacs to find required
+   preloaded Lisp.  */
 
 int
 main (int argc, char **argv)
 {
-  return android_emacs_init (argc, argv);
+  char **args;
+  int i;
+  char *bootclasspath, *emacs_class_path;
+
+  /* Allocate enough to hold the arguments to app_process.  */
+  args = alloca ((10 + argc) * sizeof *args);
+
+  /* Clear args.  */
+  memset (args, 0, (10 + argc) * sizeof *args);
+
+  /* First, figure out what program to start.  */
+#if defined __x86_64__ || defined __aarch64__
+  args[0] = (char *) "/system/bin/app_process64";
+#else
+  args[0] = (char *) "/system/bin/app_process";
+#endif
+
+  /* Next, obtain the boot class path.  */
+  bootclasspath = getenv ("BOOTCLASSPATH");
+
+  /* And the Emacs class path.  */
+  emacs_class_path = getenv ("EMACS_CLASS_PATH");
+
+  if (!bootclasspath)
+    {
+      fprintf (stderr, "The BOOTCLASSPATH environment variable"
+	       " is not set.  As a result, Emacs does not know"
+	       " how to start app_process.\n"
+	       "This is likely a change in the Android platform."
+	       "  Please report this to bug-gnu-emacs@gnu.org.\n");
+      return 1;
+    }
+
+  if (!emacs_class_path)
+    {
+      fprintf (stderr, "EMACS_CLASS_PATH not set."
+	       "  Please make sure Emacs is being started"
+	       " from within a running copy of Emacs.\n");
+      return 1;
+    }
+
+  if (asprintf (&bootclasspath, "-Djava.class.path=%s:%s",
+		bootclasspath, emacs_class_path) < 0)
+    {
+      perror ("asprintf");
+      return 1;
+    }
+
+  args[1] = bootclasspath;
+  args[2] = (char *) "/system/bin";
+  args[3] = (char *) "--nice-name=emacs";
+  args[4] = (char *) "org.gnu.emacs.EmacsNoninteractive";
+
+  /* Arguments from here on are passed to main in
+     EmacsNoninteractive.java.  */
+  args[5] = argv[0];
+
+  /* Now copy the rest of the arguments over.  */
+  for (i = 1; i < argc; ++i)
+    args[5 + i] = argv[i];
+
+  /* Finally, try to start the app_process.  */
+  execvp (args[0], args);
+
+  /* If exit fails, return an error indication.  */
+  perror ("exec");
+  return 1;
 }