feature/android 0760d5cc985 1/2: Update Android port

[Po Lu]

branch: feature/android
commit 0760d5cc985e449555a9b3879707e91f0d04111c
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Update Android port
    
    * etc/PROBLEMS: Document problem with default monospace font.
    * src/fileio.c (check_mutable_filename): Check /content as well.
    (Fcopy_file, Fdelete_directory_internal, Fdelete_file)
    (Frename_file, Fadd_name_to_file, Fmake_symbolic_link)
    (Fset_file_modes, Fset_file_times, Ffile_newer_than_file_p)
    (write_region): Adjust accordingly.
    (Fset_visited_file_modtime): Remove unnecessary restriction.
    * src/filelock.c (make_lock_file_name): Don't interlock files
    under /assets and /content.
    * src/inotify.c (Finotify_add_watch): Fix typo.
---
 etc/PROBLEMS   | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/fileio.c   | 47 ++++++++++++++++++++++++++++++-----------------
 src/filelock.c | 27 +++++++++++++++++++++++++--
 src/inotify.c  |  2 +-
 4 files changed, 106 insertions(+), 20 deletions(-)

diff --git a/etc/PROBLEMS b/etc/PROBLEMS
index 9ef231d4b16..cff96ff2863 100644
--- a/etc/PROBLEMS
+++ b/etc/PROBLEMS
@@ -3265,6 +3265,56 @@ Compose key to stop working.
 On X Windows, users should not use Emacs configured with PGTK, since
 this and many other problems do not exist on the regular X builds.
 
+* Runtime problems specific to Android
+
+** Text displayed in the default monospace font looks horrible.
+
+Droid Sans Mono (the default Monospace font which comes with Android)
+comes with instruction code designed for Microsoft's proprietary
+TrueType font scaler.  When this code is executed by Emacs to instruct
+a glyph containing more than one component, it tries to address
+"reference points" which are set to the values of two extra "phantom
+points" in the glyph, that are a proprietary extension of the MS font
+scaler.
+
+Emacs does not support these extensions, and as a result characters
+such as
+
+  ĥ
+
+display incorrectly, with the right most edge of the `h' component
+stretched very far out to the right, on some low density displays.
+
+The solution is to replace the MS-specific hinting code in Droid Sans
+Mono with automatically generated code from the FreeType project's
+"ttfautohint" program.  First, extract
+'/system/fonts/DroidSansMono.ttf' from your device:
+
+  $ adb pull /system/fonts/DroidSansMono.ttf
+  /system/fonts/DroidSansMono.ttf: 1 file pulled, 0 skipped.
+  23.1 MB/s (90208 bytes in 0.004s)
+
+install the "ttfautohint" program:
+
+  http://freetype.org/ttfautohint/
+
+generate a font file with new hinting instructions:
+
+  $ ttfautohint DroidSansMono.ttf > DroidSansMono.ttf.rpl
+
+and upload them to your device, either back to /system/fonts (which is
+allowed by free versions of Android, such as Replicant):
+
+  $ adb root
+  $ adb remount
+  $ adb push DroidSansMono.ttf.rpl /system/fonts/DroidSansMono.ttf
+
+or to the user fonts directory described in the "Android Fonts" node
+of the Emacs manual.  You may want to perform this procedure even if
+you are not seeing problems with character display, as the
+automatically generated instructions result in superior display
+results that are easier to read.
+
 * Build-time problems
 
 ** Configuration
diff --git a/src/fileio.c b/src/fileio.c
index 375019c6fb6..7bc9800aaf8 100644
--- a/src/fileio.c
+++ b/src/fileio.c
@@ -147,18 +147,31 @@ static bool e_write (int, Lisp_Object, ptrdiff_t, 
ptrdiff_t,
 
 
 /* Check that ENCODED does not lie on any special directory whose
-   contents are read only.  Signal a `file-error' if it does.  */
+   contents are read only.  Signal a `file-error' if it does.
+
+   If WRITE, then don't check that the file lies on `/content' on
+   Android.  This special exception allows writing to content
+   provider-supplied files.  */
 
 static void
-check_mutable_filename (Lisp_Object encoded)
+check_mutable_filename (Lisp_Object encoded, bool write)
 {
 #if defined HAVE_ANDROID && !defined ANDROID_STUBIFY
   if (!strcmp (SSDATA (encoded), "/assets")
       || !strncmp (SSDATA (encoded), "/assets/",
                   sizeof "/assets/" - 1))
     xsignal2 (Qfile_error,
-             build_string ("File lies on read-"
-                           "only directory"),
+             build_string ("File lies on read-only directory"),
+             encoded);
+
+  if (write)
+    return;
+
+  if (!strcmp (SSDATA (encoded), "/content")
+      || !strncmp (SSDATA (encoded), "/content/",
+                  sizeof "/content/" - 1))
+    xsignal2 (Qfile_error,
+             build_string ("File lies on read-only directory"),
              encoded);
 #endif
 }
@@ -2228,7 +2241,7 @@ permissions.  */)
 
   encoded_file = ENCODE_FILE (file);
   encoded_newname = ENCODE_FILE (newname);
-  check_mutable_filename (encoded_newname);
+  check_mutable_filename (encoded_newname, true);
 
 #ifdef WINDOWSNT
   if (NILP (ok_if_already_exists)
@@ -2488,7 +2501,7 @@ DEFUN ("delete-directory-internal", 
Fdelete_directory_internal,
   encoded_dir = ENCODE_FILE (directory);
   dir = SSDATA (encoded_dir);
 
-  check_mutable_filename (encoded_dir);
+  check_mutable_filename (encoded_dir, false);
 
   if (rmdir (dir) != 0)
     report_file_error ("Removing directory", directory);
@@ -2529,7 +2542,7 @@ With a prefix argument, TRASH is nil.  */)
     return call1 (Qmove_file_to_trash, filename);
 
   encoded_file = ENCODE_FILE (filename);
-  check_mutable_filename (encoded_file);
+  check_mutable_filename (encoded_file, false);
 
   if (unlink (SSDATA (encoded_file)) != 0 && errno != ENOENT)
     report_file_error ("Removing old name", filename);
@@ -2687,8 +2700,8 @@ This is what happens in interactive use with M-x.  */)
 
   encoded_file = ENCODE_FILE (file);
   encoded_newname = ENCODE_FILE (newname);
-  check_mutable_filename (encoded_file);
-  check_mutable_filename (encoded_newname);
+  check_mutable_filename (encoded_file, false);
+  check_mutable_filename (encoded_newname, false);
 
   bool plain_rename = (case_only_rename
                       || (!NILP (ok_if_already_exists)
@@ -2800,8 +2813,8 @@ This is what happens in interactive use with M-x.  */)
 
   encoded_file = ENCODE_FILE (file);
   encoded_newname = ENCODE_FILE (newname);
-  check_mutable_filename (encoded_file);
-  check_mutable_filename (encoded_newname);
+  check_mutable_filename (encoded_file, false);
+  check_mutable_filename (encoded_newname, false);
 
   if (link (SSDATA (encoded_file), SSDATA (encoded_newname)) == 0)
     return Qnil;
@@ -2855,8 +2868,8 @@ This happens for interactive use with M-x.  */)
 
   encoded_target = ENCODE_FILE (target);
   encoded_linkname = ENCODE_FILE (linkname);
-  check_mutable_filename (encoded_target);
-  check_mutable_filename (encoded_linkname);
+  check_mutable_filename (encoded_target, false);
+  check_mutable_filename (encoded_linkname, false);
 
   if (symlink (SSDATA (encoded_target), SSDATA (encoded_linkname)) == 0)
     return Qnil;
@@ -3598,7 +3611,7 @@ command from GNU Coreutils.  */)
     return call4 (handler, Qset_file_modes, absname, mode, flag);
 
   encoded = ENCODE_FILE (absname);
-  check_mutable_filename (encoded);
+  check_mutable_filename (encoded, false);
   char *fname = SSDATA (encoded);
   mode_t imode = XFIXNUM (mode) & 07777;
   if (fchmodat (AT_FDCWD, fname, imode, nofollow) != 0)
@@ -3671,7 +3684,7 @@ TIMESTAMP is in the format of `current-time'. */)
     return call4 (handler, Qset_file_times, absname, timestamp, flag);
 
   Lisp_Object encoded_absname = ENCODE_FILE (absname);
-  check_mutable_filename (encoded_absname);
+  check_mutable_filename (encoded_absname, false);
 
   if (utimensat (AT_FDCWD, SSDATA (encoded_absname), ts, nofollow) != 0)
     {
@@ -3722,7 +3735,6 @@ otherwise, if FILE2 does not exist, the answer is t.  */)
     return call3 (handler, Qfile_newer_than_file_p, absname1, absname2);
 
   encoded = ENCODE_FILE (absname1);
-  check_mutable_filename (encoded);
 
   int err1;
   if (emacs_fstatat (AT_FDCWD, SSDATA (encoded), &st1, 0) == 0)
@@ -5368,6 +5380,8 @@ write_region (Lisp_Object start, Lisp_Object end, 
Lisp_Object filename,
     }
 
   encoded_filename = ENCODE_FILE (filename);
+  check_mutable_filename (encoded_filename, false);
+
   fn = SSDATA (encoded_filename);
   open_flags = O_WRONLY | O_CREAT;
   open_flags |= EQ (mustbenew, Qexcl) ? O_EXCL : !NILP (append) ? 0 : O_TRUNC;
@@ -5942,7 +5956,6 @@ in `current-time' or an integer flag as returned by 
`visited-file-modtime'.  */)
        return call2 (handler, Qset_visited_file_modtime, Qnil);
 
       encoded = ENCODE_FILE (filename);
-      check_mutable_filename (encoded);
 
       if (emacs_fstatat (AT_FDCWD, SSDATA (encoded), &st, 0)
          == 0)
diff --git a/src/filelock.c b/src/filelock.c
index 45eac5a19a1..be551fc876f 100644
--- a/src/filelock.c
+++ b/src/filelock.c
@@ -659,8 +659,31 @@ lock_if_free (lock_info_type *clasher, Lisp_Object lfname)
 static Lisp_Object
 make_lock_file_name (Lisp_Object fn)
 {
-  Lisp_Object lock_file_name = call1 (Qmake_lock_file_name,
-                                     Fexpand_file_name (fn, Qnil));
+  Lisp_Object lock_file_name;
+#if defined HAVE_ANDROID && !defined ANDROID_STUBIFY
+  char *name;
+#endif
+
+  fn = Fexpand_file_name (fn, Qnil);
+
+#if defined HAVE_ANDROID && !defined ANDROID_STUBIFY
+  /* Files in /assets and /contents can't have lock files on Android
+     as these directories are fabrications of android.c, and backed by
+     read only data.  */
+
+  name = SSDATA (fn);
+
+  if (strcmp (name, "/assets")
+      || strcmp (name, "/assets/")
+      || strcmp (name, "/content")
+      || strcmp (name, "/content/")
+      || strncmp (name, "/assets/", sizeof "/assets")
+      || strncmp (name, "/content/", sizeof "/content"))
+  return Qnil;
+#endif
+
+  lock_file_name = call1 (Qmake_lock_file_name, fn);
+
   return !NILP (lock_file_name) ? ENCODE_FILE (lock_file_name) : Qnil;
 }
 
diff --git a/src/inotify.c b/src/inotify.c
index b2a48884efa..844bf54105c 100644
--- a/src/inotify.c
+++ b/src/inotify.c
@@ -445,7 +445,7 @@ IN_ONESHOT  */)
       || strcmp (name, "/content")
       || strcmp (name, "/content/")
       || strncmp (name, "/assets/", sizeof "/assets")
-      || strncmp (name, "/content", sizeof "/content"))
+      || strncmp (name, "/content/", sizeof "/content"))
     return Qnil;
 #endif