Plugin Interface: Add GUI callbacks

 Rename ext_menubar to a more appropriate plugin_if.

 External menus can be implemented by plugins to present
 additional menus for deep-packet analysis. One side-effect
 of such menus being implemented as plugins is, that they
 are being executed in different threads and therefore can
 only use limited access to the main GUI. Also, there is
 no safe cross-gui (GTK and Qt) way for many features.

 This patch implements a first functionality, by which a
 plugin implemented using ext_menubar can apply a display
 filter to the main view.

 For now the implementation supports filtering, as well as
 saving a preference.

Change-Id: Iffe4caa954bbeb8ce356352de4dae348a50efba9
Reviewed-on: https://code.wireshark.org/review/8773
Reviewed-by: Roland Knall <rknall@gmail.com>
Petri-Dish: Anders Broman <a.broman58@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>

4 files changed, 124 insertions, 13 deletions

diff --git a/epan/CMakeLists.txt b/epan/CMakeLists.txt
index aa37191ddc..36d141bf0d 100644
--- a/epan/CMakeLists.txt
+++ b/epan/CMakeLists.txt
@@ -1600,7 +1600,7 @@ set(LIBWIRESHARK_FILES
 	except.c
 	expert.c
 	exported_pdu.c
-	ext_menubar.c
+	plugin_if.c
 	filter_expressions.c
 	follow.c
 	frame_data.c
diff --git a/epan/Makefile.common b/epan/Makefile.common
index a8c3bb5ad1..fe81b1c7ea 100644
--- a/epan/Makefile.common
+++ b/epan/Makefile.common
@@ -51,7 +51,7 @@ LIBWIRESHARK_SRC =		\
 	except.c		\
 	expert.c		\
 	exported_pdu.c		\
-	ext_menubar.c		\
+	plugin_if.c		\
 	filter_expressions.c	\
 	follow.c		\
 	frame_data.c		\
@@ -192,7 +192,7 @@ LIBWIRESHARK_INCLUDES =		\
 	exceptions.h		\
 	expert.h		\
 	exported_pdu.h		\
-	ext_menubar.h      \
+	plugin_if.h      \
 	filter_expressions.h	\
 	follow.h		\
 	frame_data.h		\
diff --git a/epan/ext_menubar.c b/epan/plugin_if.c
index 25501520c7..62244dd4fd 100644
--- a/epan/ext_menubar.c
+++ b/epan/plugin_if.c
@@ -1,9 +1,12 @@
-/* ext_menubar.c
- * A menubar API for Wireshark dissectors
+/* plugin_if.c
+ * An API for Wireshark plugins
  *
  * This enables wireshark dissectors, especially those implemented by plugins
  * to register menubar entries, which then will call a pre-defined callback
- * function for the dissector or plugin
+ * function for the dissector or plugin.
+ *
+ * Also it implements additional methods, which allow plugins to interoperate
+ * with the main GUI.
  *
  * Wireshark - Network traffic analyzer
  * By Gerald Combs <gerald@wireshark.org>
@@ -30,7 +33,7 @@
 #include <epan/epan.h>
 #include <epan/proto.h>
 
-#include "ext_menubar.h"
+#include "plugin_if.h"
 
 static GList * menubar_entries = NULL;
 static GList * menubar_menunames = NULL;
@@ -158,6 +161,84 @@ extern void ext_menubar_add_separator(ext_menu_t *parent)
     ext_menubar_add_generic_entry ( EXT_MENUBAR_SEPARATOR, parent, g_strdup("-"), NULL, NULL, NULL );
 }
 
+/* Implementation of GUI callback methods follows.
+ * This is a necessity, as using modern UI systems, gui interfaces often operate
+ * in different threads then the calling application. Even more so, if the calling
+ * application is implemented using a separate plugin. Therefore the external menubars
+ * cannot call gui functionality directly, the gui has to perform the function within
+ * it' own scope. */
+
+static GHashTable * plugin_if_callback_functions;
+
+static void
+plugin_if_init_hashtable(void)
+{
+    if ( plugin_if_callback_functions == 0 )
+        plugin_if_callback_functions = g_hash_table_new(g_int_hash, g_int_equal);
+}
+
+static void plugin_if_call_gui_cb(plugin_if_callback_t actionType, GHashTable * dataSet)
+{
+    plugin_if_gui_cb action;
+    gint * key = 0;
+
+    key = (gint *)g_malloc0(sizeof(gint));
+    *key = (gint) actionType;
+
+    plugin_if_init_hashtable();
+
+    if ( g_hash_table_size(plugin_if_callback_functions) != 0 )
+    {
+        if ( g_hash_table_contains(plugin_if_callback_functions, key) )
+        {
+            action = (plugin_if_gui_cb)g_hash_table_lookup(plugin_if_callback_functions, key);
+            if ( action != NULL )
+                action(dataSet);
+        }
+    }
+}
+
+extern void plugin_if_apply_filter(const char * filter_string, gboolean force)
+{
+    plugin_if_callback_t actionType;
+    GHashTable * dataSet = NULL;
+
+    actionType = ( force == TRUE ) ? PLUGIN_IF_FILTER_ACTION_APPLY : PLUGIN_IF_FILTER_ACTION_PREPARE;
+    dataSet = g_hash_table_new(g_str_hash, g_str_equal);
+
+    g_hash_table_insert( dataSet, g_strdup("action_type"), (gpointer) &actionType );
+    g_hash_table_insert( dataSet, g_strdup("filter_string"), g_strdup(filter_string) );
+    g_hash_table_insert( dataSet, g_strdup("force"), (gpointer) &force );
+
+    plugin_if_call_gui_cb(actionType, dataSet);
+}
+
+extern void plugin_if_save_preference(const char * pref_module, const char * pref_key, const char * pref_value)
+{
+    GHashTable * dataSet = NULL;
+
+    dataSet = g_hash_table_new(g_str_hash, g_str_equal);
+
+    g_hash_table_insert( dataSet, g_strdup("pref_module"), g_strdup(pref_module) );
+    g_hash_table_insert( dataSet, g_strdup("pref_key"), g_strdup(pref_key) );
+    g_hash_table_insert( dataSet, g_strdup("pref_value"), g_strdup(pref_value) );
+
+    plugin_if_call_gui_cb(PLUGIN_IF_PREFERENCE_SAVE, dataSet);
+}
+
+extern void plugin_if_register_gui_cb(plugin_if_callback_t actionType, plugin_if_gui_cb callback)
+{
+    gint * key = 0;
+
+    key = (gint *)g_malloc0(sizeof(gint));
+    *key = actionType;
+
+    plugin_if_init_hashtable();
+
+    if ( ! g_hash_table_contains(plugin_if_callback_functions, key ) )
+        g_hash_table_insert(plugin_if_callback_functions, key, callback);
+}
+
 /*
  * Editor modelines
  *
diff --git a/epan/ext_menubar.h b/epan/plugin_if.h
index acffa8f2e8..df9ea6e846 100644
--- a/epan/ext_menubar.h
+++ b/epan/plugin_if.h
@@ -1,9 +1,12 @@
-/* ext_menubar.h
- * A menubar API for Wireshark dissectors
+/* plugin_if.h
+ * An API for Wireshark plugins
  *
  * This enables wireshark dissectors, especially those implemented by plugins
  * to register menubar entries, which then will call a pre-defined callback
- * function for the dissector or plugin
+ * function for the dissector or plugin.
+ *
+ * Also it implements additional methods, which allow plugins to interoperate
+ * with the main GUI.
  *
  * Wireshark - Network traffic analyzer
  * By Gerald Combs <gerald@wireshark.org>
@@ -23,8 +26,8 @@
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
-#ifndef EPAN_EXT_MENUBAR_H_
-#define EPAN_EXT_MENUBAR_H_
+#ifndef EPAN_PLUGIN_IF_H
+#define EPAN_PLUGIN_IF_H
 
 #include <config.h>
 
@@ -146,6 +149,33 @@ WS_DLL_PUBLIC void ext_menubar_add_separator(ext_menu_t *parent_menu);
 WS_DLL_PUBLIC void ext_menubar_add_website(ext_menu_t * parent, const gchar *label,
         const gchar *tooltip, const gchar *url);
 
+
+/*
+ * Enumeration of possible actions, which are registered in GUI interfaces
+ */
+typedef enum
+{
+    /* Applies a given string as filter */
+    PLUGIN_IF_FILTER_ACTION_APPLY,
+
+    /* Prepares the given string as filter */
+    PLUGIN_IF_FILTER_ACTION_PREPARE,
+
+    /* Saves a preference entry */
+    PLUGIN_IF_PREFERENCE_SAVE
+} plugin_if_callback_t;
+
+
+typedef void (*plugin_if_gui_cb)(gconstpointer user_data);
+
+WS_DLL_PUBLIC void plugin_if_register_gui_cb(plugin_if_callback_t actionType, plugin_if_gui_cb callback);
+
+/* Applies the given filter string as display filter */
+WS_DLL_PUBLIC void plugin_if_apply_filter(const char * filter_string, gboolean force);
+
+/* Saves the given preference to the main preference storage */
+WS_DLL_PUBLIC void plugin_if_save_preference(const char * pref_module, const char * pref_key, const char * pref_value);
+
 /* Private Method for retrieving the menubar entries
  *
  * Is only to be used by the UI interfaces to retrieve the menu entries
@@ -156,7 +186,7 @@ WS_DLL_PUBLIC GList * ext_menubar_get_entries(void);
 }
 #endif /* __cplusplus */
 
-#endif /* EPAN_EXT_MENUBAR_H_ */
+#endif /* EPAN_PLUGIN_IF_H */
 
 /*
  * Editor modelines