Auto-detection of MH format

@@ -21,20 +21,113 @@
 
 #ifdef ENABLE_MH
 
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
 #include <errno.h>
+#include <unistd.h>
+#include <dirent.h>
 
+#include <url0.h>
 #include <folder0.h>
 #include <registrar0.h>
 
+static int
+_mh_folder_init (folder_t folder ARG_UNUSED)
+{
+  return 0;
+}
+
+/* Check if NAME is a valid MH message name */
+static int
+mh_message_name_p (const char *name)
+{
+  for ( ; *name; name++)
+    if (!isdigit (*name))
+      return 0;
+  return 1;
+}
+
+/* Check if directory NAME is a valid MH folder directory */
+static int
+mh_dir_p (const char *name)
+{
+  DIR *dir;
+  struct dirent *entry;
+  int result = 0;
+  
+  dir = opendir (name);
+  if (!dir)
+    return 1; /* Maybe yes */
+
+  while (!result && (entry = readdir (dir)))
+    {
+      switch (entry->d_name[0])
+	{
+	case '.':
+	  result = strcmp (entry->d_name, ".mh_sequences") == 0;
+	  break;
+
+	case ',':
+	  result = mh_message_name_p (entry->d_name + 1);
+	  break;
+
+	default:
+	  result = mh_message_name_p (entry->d_name);
+	  break;
+	}
+    }
+  closedir (dir);
+  return result;
+}
+
+static int
+_mh_is_scheme (record_t record, const char *url)
+{
+  if (!url || !record->scheme)
+    return 0;
+
+  if (strncmp (record->scheme, url, strlen (record->scheme)) == 0)
+    return 1;
+
+  if (strncmp (MU_PATH_SCHEME, url, MU_PATH_SCHEME_LEN) == 0)
+    {
+      /* Attemp auto-detection */
+      struct stat st;
+      
+      if (stat (url, &st) < 0)
+	return 1; /* mailbox_open will complain */
+
+      if (!S_ISDIR (st.st_mode))
+	return 0;
+
+      return mh_dir_p (url);
+    }
+
+  return 0;
+}
+
+/*
+  MH url
+  mh:path
+*/
+static int
+_mh_url_init (url_t url)
+{
+  return amd_url_init (url, MU_MH_SCHEME);
+}
+
 static struct _record _mh_record =
 {
   MU_MH_SCHEME,
-  _url_mh_init, /* Url init.  */
+  _mh_url_init, /* Url init.  */
   _mailbox_mh_init, /* Mailbox init.  */
   NULL, /* Mailer init.  */
-  _folder_mh_init, /* Folder init.  */
+  _mh_folder_init, /* Folder init.  */
   NULL, /* back pointer.  */
-  NULL, /* _is_scheme method.  */
+  _mh_is_scheme, /* _is_scheme method.  */
   NULL, /* _get_url method.  */
   NULL, /* _get_mailbox method.  */
   NULL, /* _get_mailer method.  */
@@ -42,12 +135,6 @@ static struct _record _mh_record =
 };
 record_t mh_record = &_mh_record;
 
-int
-_folder_mh_init (folder_t folder ARG_UNUSED)
-{
-  return 0;
-}
-
 #else
 #include <stdio.h>
 #include <registrar0.h>