wiretap: register most built-in file types from its module.

Remove most of the built-in file types from the table in
wiretap/file_access.c and, instead, have the file types register
themselves, using wtap_register_file_type_subtypes().

This reduces the source code changes needed to add a new file type from
three (add the handler, add the file type to the table in file_access.c,
add a #define for the file type in wiretap/wtap.h) to one (add the
handler).  (It also requires adding the handler's source file to
wiretap/CMakeLists.txt, but that's required in both cases.)

A few remain because the WTAP_FILE_TYPE_SUBTYPE_ #define is used
elsewhere; that needs to be fixed.

Fix the wiretap/CMakefile.txt file to scan k12text.l, as that now
contains a registration routine.  In the process, avoid scanning files
that don't implement a file type and won't ever have a registration
routine.

Add a Lua routine to fetch the total number of file types; we use that
in some code to construct the wtap_filetypes table, which we need to do
in order to continue to have all the values that used to come from the
WTAP_FILE_TYPE_SUBTYPE_ types.

While we're at it, add modelines to a file that lacked them.

1 files changed, 17 insertions, 1 deletions

diff --git a/wiretap/ipfix.c b/wiretap/ipfix.c
index 44f5808309..5eb2e7a53e 100644
--- a/wiretap/ipfix.c
+++ b/wiretap/ipfix.c
@@ -94,6 +94,10 @@ typedef struct ipfix_set_header_s {
 #define IPFIX_SET_HDR_SIZE 4
 
 
+static int ipfix_file_type_subtype = -1;
+
+void register_ipfix(void);
+
 /* Read IPFIX message header from file.  Return true on success.  Set *err to
  * 0 on EOF, any other value for "real" errors (EOF is ok, since return
  * value is still FALSE)
@@ -269,7 +273,7 @@ ipfix_open(wtap *wth, int *err, gchar **err_info)
     wth->file_tsprec = WTAP_TSPREC_SEC;
     wth->subtype_read = ipfix_read;
     wth->subtype_seek_read = ipfix_seek_read;
-    wth->file_type_subtype = WTAP_FILE_TYPE_SUBTYPE_IPFIX;
+    wth->file_type_subtype = ipfix_file_type_subtype;
 
     /*
      * Add an IDB; we don't know how many interfaces were
@@ -324,6 +328,18 @@ ipfix_seek_read(wtap *wth, gint64 seek_off, wtap_rec *rec,
     return TRUE;
 }
 
+static const struct file_type_subtype_info ipfix_info = {
+    "IPFIX File Format", "ipfix", "pfx", "ipfix",
+    FALSE, FALSE, 0,
+    NULL, NULL, NULL
+};
+
+void register_ipfix(void)
+{
+    ipfix_file_type_subtype = wtap_register_file_type_subtypes(&ipfix_info,
+                                                               WTAP_FILE_TYPE_SUBTYPE_UNKNOWN);
+}
+
 /*
  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
  *