Correct JNI string error checking and miscellaneous corrections

* src/android-emacs.c (main): Do not attempt to load the
bootstrap class path, which is redundant on all Android releases.

* src/android.c (initEmacs, android_browse_url): Do not assume
exceptions will be raised if GetStringUTFChars fails.  Decode
Android JNI strings as Qandroid_jni.

* src/androidvfs.c (android_saf_check_nonnull): New function.
(android_saf_new_mkdir): Likewise.

src/android-emacs.c

@@ -52,49 +52,6 @@ main (int argc, char **argv)
   args[0] = (char *) "/system/bin/app_process";
 #endif /* __x86_64__ || __aarch64__ || __mips64 */
 
-  /* Machines with ART require the boot classpath to be manually
-     specified.  Machines with Dalvik however refuse to do so, as they
-     open the jars inside the BOOTCLASSPATH environment variable at
-     startup, resulting in the following crash:
-
-     W/dalvikvm( 1608): Refusing to reopen boot DEX
-     '/system/framework/core.jar'
-     W/dalvikvm( 1608): Refusing to reopen boot DEX
-     '/system/framework/bouncycastle.jar'
-     E/dalvikvm( 1608): Too many exceptions during init (failed on
-     'Ljava/io/IOException;' 'Re-opening BOOTCLASSPATH DEX files is
-     not allowed')
-     E/dalvikvm( 1608): VM aborting  */
-
-#if HAVE_DECL_ANDROID_GET_DEVICE_API_LEVEL
-  if (android_get_device_api_level () < 21)
-    {
-      bootclasspath = NULL;
-      goto skip_setup;
-    }
-#else /* !HAVE_DECL_ANDROID_GET_DEVICE_API_LEVEL */
-  if (__ANDROID_API__ < 21)
-    {
-      bootclasspath = NULL;
-      goto skip_setup;
-    }
-#endif /* HAVE_DECL_ANDROID_GET_DEVICE_API_LEVEL */
-
-  /* Next, obtain the boot class path.  */
-  bootclasspath = getenv ("BOOTCLASSPATH");
-
-  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;
-    }
-
- skip_setup:
-
   /* And the Emacs class path.  */
   emacs_class_path = getenv ("EMACS_CLASS_PATH");
 
@@ -115,23 +72,11 @@ main (int argc, char **argv)
   if (ld_library_path)
     setenv ("LD_LIBRARY_PATH", ld_library_path, 1);
 
-  if (bootclasspath)
+  if (asprintf (&bootclasspath, "-Djava.class.path=%s",
+		emacs_class_path) < 0)
     {
-      if (asprintf (&bootclasspath, "-Djava.class.path=%s:%s",
-		    bootclasspath, emacs_class_path) < 0)
-	{
-	  perror ("asprintf");
-	  return 1;
-	}
-    }
-  else
-    {
-      if (asprintf (&bootclasspath, "-Djava.class.path=%s",
-		    emacs_class_path) < 0)
-	{
-	  perror ("asprintf");
-	  return 1;
-	}
+      perror ("asprintf");
+      return 1;
     }
 
   args[1] = bootclasspath;

src/android.c

@@ -2019,6 +2019,8 @@ NATIVE_NAME (initEmacs) (JNIEnv *env, jobject object, jarray argv,
       c_argument
 	= (*env)->GetStringUTFChars (env, (jstring) dump_file_object,
 				     NULL);
+      if (!c_argument)
+	emacs_abort ();
 
       /* Copy the Java string data once.  */
       dump_file = strdup (c_argument);
@@ -6497,18 +6499,18 @@ android_browse_url (Lisp_Object url, Lisp_Object send)
   buffer = (*android_java_env)->GetStringUTFChars (android_java_env,
 						   (jstring) value,
 						   NULL);
-  android_exception_check_1 (value);
+  android_exception_check_nonnull ((void *) buffer, value);
 
   /* Otherwise, build the string describing the error.  */
-  tem = build_string_from_utf8 (buffer);
+  tem = build_unibyte_string (buffer);
 
   (*android_java_env)->ReleaseStringUTFChars (android_java_env,
 					      (jstring) value,
 					      buffer);
 
-  /* And return it.  */
+  /* And decode and return the same.  */
   ANDROID_DELETE_LOCAL_REF (value);
-  return tem;
+  return code_convert_string_norecord (tem, Qandroid_jni, false);
 }
 
 /* Tell the system to restart Emacs in a short amount of time, and

src/androidvfs.c

@@ -3162,6 +3162,37 @@ android_saf_exception_check (int n, ...)
   return 1;
 }
 
+/* Verify that OBJECT is non-NULL.  If NULL, free each of the N local
+   references given as arguments, and clear exceptions.
+
+   Value is 1 if it be NULL, 0 otherwise.  */
+
+static int
+android_saf_check_nonnull (jobject object, int n, ...)
+{
+  va_list ap;
+
+  if (object)
+    return 0;
+
+  va_start (ap, n);
+
+  /* Clear the active exception, making it safe to subsequently call
+     other JNI functions.  */
+  (*android_java_env)->ExceptionClear (android_java_env);
+
+  /* Delete each of the N arguments.  */
+
+  while (n > 0)
+    {
+      ANDROID_DELETE_LOCAL_REF (va_arg (ap, jobject));
+      n--;
+    }
+
+  va_end (ap);
+  return 1;
+}
+
 
 
 /* Content authority-based vnode implementation.
@@ -6428,7 +6459,7 @@ android_saf_new_mkdir (struct android_vnode *vnode, mode_t mode)
   new_doc_id = (*android_java_env)->GetStringUTFChars (android_java_env,
 						       new_id, NULL);
 
-  if (android_saf_exception_check (3, name, id, uri))
+  if (android_saf_check_nonnull (new_doc_id, 3, name, id, uri))
     return -1;
 
   xfree (vp->document_id);