Fix compatibility issues with Android clipboards

* java/org/gnu/emacs/EmacsClipboard.java (getClipboardData):
Return an AssetFileDescriptor.

* java/org/gnu/emacs/EmacsContextMenu.java (onMenuItemClick):
Typo corrections in commentary.

* java/org/gnu/emacs/EmacsOpenActivity.java (onCreate): Raise
minimum version on which to read file descriptors from
ParcelFileDescriptor objects to Honeycomb.

* java/org/gnu/emacs/EmacsSdk11Clipboard.java
(getClipboardData): Return the asset file descriptor.

* java/org/gnu/emacs/EmacsSdk8Clipboard.java (getClipboardData):
Adjust return type to match.

* src/android.h (struct android_parcel_file_descriptor_class):
Move from androidselect.c.

* src/androidselect.c (fd_class): Export function.
(android_init_emacs_clipboard): Adjust signature of
getClipboardData.
(android_init_asset_file_descriptor, close_asset_fd)
(extract_fd_offsets): New functions.
(Fandroid_get_clipboard_data): Extract file descriptor and
offset from the AssetFileDescriptor here, rather than in
getClipboardData.
(init_androidselect): Call android_init_asset_file_descriptor.

* src/androidvfs.c (android_init_fd_class): Export and enable
calling this function more than once.

java/org/gnu/emacs/EmacsClipboard.java

@@ -19,6 +19,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 
 package org.gnu.emacs;
 
+import android.content.res.AssetFileDescriptor;
 import android.os.Build;
 
 /* This class provides helper code for accessing the clipboard,
@@ -32,7 +33,7 @@ public abstract class EmacsClipboard
   public abstract byte[] getClipboard ();
 
   public abstract byte[][] getClipboardTargets ();
-  public abstract long[] getClipboardData (byte[] target);
+  public abstract AssetFileDescriptor getClipboardData (byte[] target);
 
   /* Create the correct kind of clipboard for this system.  */
 

java/org/gnu/emacs/EmacsContextMenu.java

@@ -108,8 +108,8 @@ public final class EmacsContextMenu
 	     will normally confuse Emacs into thinking that the
 	     context menu has been dismissed.  Wrong!
 
-	     Setting this flag makes EmacsActivity to only handle
-	     SubMenuBuilder being closed, which always means the menu
+	     Setting this flag prompts EmacsActivity to only handle
+	     SubMenuBuilders being closed, which always means the menu
 	     has actually been dismissed.
 
 	     However, these extraneous events aren't sent on devices

java/org/gnu/emacs/EmacsOpenActivity.java

@@ -19,29 +19,23 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 
 package org.gnu.emacs;
 
-/* This class makes the Emacs server work reasonably on Android.
+/* Opening external documents on Android.
 
-   There is no way to make the Unix socket publicly available on
-   Android.
+   This activity is registered as an application capable of opening text
+   files and files in several other formats that Emacs understands, and
+   assumes responsibility for deriving file names from the files
+   provided to `onCreate', potentially copying them to temporary
+   directories in the process, and invoking `emacsclient' with suitable
+   arguments to open the same.  In this respect, it fills the role of
+   `etc/emacs.desktop' on XDG systems.
 
-   Instead, this activity tries to connect to the Emacs server, to
-   make it open files the system asks Emacs to open, and to emulate
-   some reasonable behavior when Emacs has not yet started.
+   It is also registered as a handler for mailto URIs, in which capacity
+   it constructs invocations of `emacsclient' so as to start
+   `message-mailto' with their contents and attachments, much like
+   `etc/emacs-mail.desktop'.
 
-   First, Emacs registers itself as an application that can open text
-   and image files.
-
-   Then, when the user is asked to open a file and selects ``Emacs''
-   as the application that will open the file, the system pops up a
-   window, this activity, and calls the `onCreate' function.
-
-   `onCreate' then tries very to find the file name of the file that
-   was selected, and give it to emacsclient.
-
-   If emacsclient successfully opens the file, then this activity
-   starts EmacsActivity (to bring it on to the screen); otherwise, it
-   displays the output of emacsclient or any error message that occurs
-   and exits.  */
+   As with all other activities, it is registered in the package
+   manifest file.  */
 
 import android.app.AlertDialog;
 import android.app.Activity;
@@ -628,11 +622,12 @@ public final class EmacsOpenActivity extends Activity
 
 	    if (scheme.equals ("content")
 		/* Retrieving the native file descriptor of a
-		   ParcelFileDescriptor requires Honeycomb, and
+		   ParcelFileDescriptor requires Honeycomb MR1, and
 		   proceeding without this capability is pointless on
 		   systems before KitKat, since Emacs doesn't support
 		   opening content files on those.  */
-		&& Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB)
+		&& (Build.VERSION.SDK_INT
+		    >= Build.VERSION_CODES.HONEYCOMB_MR1))
 	      {
 		/* This is one of the annoying Android ``content''
 		   URIs.  Most of the time, there is actually an

java/org/gnu/emacs/EmacsSdk11Clipboard.java

@@ -207,8 +207,9 @@ public final class EmacsSdk11Clipboard extends EmacsClipboard
   /* Return the clipboard data for the given target, or NULL if it
      does not exist.
 
-     Value is normally an array of three longs: the file descriptor,
-     the start offset of the data, and its length; length may be
+     Value is normally an asset file descriptor, which in turn holds
+     three important values: the file descriptor, the start offset of
+     the data, and its length; length may be
      AssetFileDescriptor.UNKNOWN_LENGTH, meaning that the data extends
      from that offset to the end of the file.
 
@@ -217,15 +218,13 @@ public final class EmacsSdk11Clipboard extends EmacsClipboard
      solely of a URI.  */
 
   @Override
-  public long[]
+  public AssetFileDescriptor
   getClipboardData (byte[] target)
   {
     ClipData data;
     String mimeType;
-    int fd;
     AssetFileDescriptor assetFd;
     Uri uri;
-    long[] value;
 
     /* Decode the target given by Emacs.  */
     try
@@ -245,8 +244,6 @@ public final class EmacsSdk11Clipboard extends EmacsClipboard
     if (data == null || data.getItemCount () < 1)
       return null;
 
-    fd = -1;
-
     try
       {
 	uri = data.getItemAt (0).getUri ();
@@ -257,52 +254,15 @@ public final class EmacsSdk11Clipboard extends EmacsClipboard
 	/* Now open the file descriptor.  */
 	assetFd = resolver.openTypedAssetFileDescriptor (uri, mimeType,
 							 null);
-
-	/* Duplicate the file descriptor.  */
-	fd = assetFd.getParcelFileDescriptor ().getFd ();
-	fd = EmacsNative.dup (fd);
-
-	/* Return the relevant information.  */
-	value = new long[] { fd, assetFd.getStartOffset (),
-			     assetFd.getLength (), };
-
-	/* Close the original offset.  */
-	assetFd.close ();
+	return assetFd;
       }
     catch (SecurityException e)
       {
-	/* Guarantee a file descriptor duplicated or detached is
-	   ultimately closed if an error arises.  */
-
-	if (fd != -1)
-	  EmacsNative.close (fd);
-
 	return null;
       }
     catch (FileNotFoundException e)
       {
-	/* Guarantee a file descriptor duplicated or detached is
-	   ultimately closed if an error arises.  */
-
-	if (fd != -1)
-	  EmacsNative.close (fd);
-
 	return null;
       }
-    catch (IOException e)
-      {
-	/* Guarantee a file descriptor duplicated or detached is
-	   ultimately closed if an error arises.  */
-
-	if (fd != -1)
-	  EmacsNative.close (fd);
-
-	return null;
-      }
-
-    /* Don't return value if the file descriptor couldn't be
-       created.  */
-
-    return fd != -1 ? value : null;
   }
 };

java/org/gnu/emacs/EmacsSdk8Clipboard.java

@@ -25,6 +25,8 @@ package org.gnu.emacs;
 import android.text.*;
 
 import android.content.Context;
+import android.content.res.AssetFileDescriptor;
+
 import android.util.Log;
 
 import java.io.UnsupportedEncodingException;
@@ -129,9 +131,10 @@ public final class EmacsSdk8Clipboard extends EmacsClipboard
   /* Return the clipboard data for the given target, or NULL if it
      does not exist.
 
-     Value is normally an array of three longs: the file descriptor,
-     the start offset of the data, and its length; length may be
-     AssetFileDescriptor.UNKOWN_LENGTH, meaning that the data extends
+     Value is normally an asset file descriptor, which in turn holds
+     three important values: the file descriptor, the start offset of
+     the data, and its length; length may be
+     AssetFileDescriptor.UNKNOWN_LENGTH, meaning that the data extends
      from that offset to the end of the file.
 
      Do not use this function to open text targets; use `getClipboard'
@@ -139,7 +142,7 @@ public final class EmacsSdk8Clipboard extends EmacsClipboard
      solely of a URI.  */
 
   @Override
-  public long[]
+  public AssetFileDescriptor
   getClipboardData (byte[] target)
   {
     return null;