Extensions: public include

This patch defines a new type of interactions between the GUI and
so-called 'extensions'.
These extensions are dynamic plugins, that can be scripted, and they can
create GUI dialogs with widgets (like text fields, buttons, ...).

include/vlc_extensions.h

+/*****************************************************************************
+ * vlc_extension.h: Extensions (meta data, web information, ...)
+ *****************************************************************************
+ * Copyright (C) 2009-2010 VideoLAN and authors
+ * $Id$
+ *
+ * Authors: Jean-Philippe André < jpeg # videolan.org >
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifndef VLC_EXTENSIONS_H
+#define VLC_EXTENSIONS_H
+
+#include "vlc_common.h"
+#include "vlc_arrays.h"
+
+/* Structures */
+typedef struct extensions_manager_sys_t extensions_manager_sys_t;
+typedef struct extensions_manager_t extensions_manager_t;
+typedef struct extension_sys_t extension_sys_t;
+
+/** Extension descriptor */
+typedef struct {
+    char *psz_title;          /**< Display title (ro) */
+    char *psz_name;           /**< Real name of the extension (ro) */
+    extension_sys_t *p_sys;   /**< Reserved for the manager module */
+} extension_t;
+
+/** Extensions manager object */
+struct extensions_manager_t
+{
+    VLC_COMMON_MEMBERS
+
+    module_t *p_module;                /**< Extensions manager module */
+    extensions_manager_sys_t *p_sys;   /**< Reserved for the module */
+
+    DECL_ARRAY(extension_t*) extensions; /**< Array of extension descriptors */
+
+    /** Control, see extension_Control */
+    int ( *pf_control ) ( extensions_manager_t*, int, va_list );
+};
+
+/* Control commands */
+enum
+{
+    /* Control extensions */
+    EXTENSION_ACTIVATE,       /**< arg1: extension_t* */
+    EXTENSION_DEACTIVATE,     /**< arg1: extension_t* */
+    EXTENSION_IS_ACTIVATED,   /**< arg1: extension_t*, arg2: bool* */
+    EXTENSION_HAS_MENU,       /**< arg1: extension_t* */
+    EXTENSION_GET_MENU,       /**< arg1: extension_t*, arg2: char***, arg3: uint16_t** */
+    EXTENSION_TRIGGER_ONLY,   /**< arg1: extension_t*, arg2: bool* */
+    EXTENSION_TRIGGER,        /**< arg1: extension_t* */
+    EXTENSION_TRIGGER_MENU,   /**< arg1: extension_t*, int (uint16_t) */
+};
+
+/**
+ * Control function for extensions.
+ * Every GUI -> extension command will go through this function.
+ **/
+static inline int extension_Control( extensions_manager_t *p_mgr,
+                                     int i_control, ... )
+{
+    va_list args;
+    va_start( args, i_control );
+    int i_ret = p_mgr->pf_control( p_mgr, i_control, args );
+    va_end( args );
+    return i_ret;
+}
+
+/**
+ * Helper for extension_HasMenu, extension_IsActivated...
+ * Do not use.
+ **/
+static inline bool __extension_GetBool( extensions_manager_t *p_mgr,
+                                        extension_t *p_ext,
+                                        int i_flag,
+                                        bool b_default )
+{
+    bool b = b_default;
+    int i_ret = extension_Control( p_mgr, i_flag, p_ext, &b );
+    if( i_ret != VLC_SUCCESS )
+        return b_default;
+    else
+        return b;
+}
+
+/** Activate or trigger an extension */
+#define extension_Activate( mgr, ext ) \
+        extension_Control( mgr, EXTENSION_ACTIVATE, ext )
+
+/** Trigger the extension. Attention: NOT multithreaded! */
+#define extension_Trigger( mgr, ext ) \
+        extension_Control( mgr, EXTENSION_TRIGGER, ext )
+
+/** Deactivate an extension */
+#define extension_Deactivate( mgr, ext ) \
+        extension_Control( mgr, EXTENSION_DEACTIVATE, ext )
+
+/** Is this extension activated? */
+#define extension_IsActivated( mgr, ext ) \
+        __extension_GetBool( mgr, ext, EXTENSION_IS_ACTIVATED, false )
+
+/** Does this extension have a sub-menu? */
+#define extension_HasMenu( mgr, ext ) \
+        __extension_GetBool( mgr, ext, EXTENSION_HAS_MENU, false )
+
+/** Get this extension's sub-menu */
+static inline int extension_GetMenu( extensions_manager_t *p_mgr,
+                                     extension_t *p_ext,
+                                     char ***pppsz,
+                                     uint16_t **ppi )
+{
+    return extension_Control( p_mgr, EXTENSION_GET_MENU, p_ext, pppsz, ppi );
+}
+
+/** Trigger an entry of the extension menu */
+static inline int extension_TriggerMenu( extensions_manager_t *p_mgr,
+                                         extension_t *p_ext,
+                                         uint16_t i )
+{
+    return extension_Control( p_mgr, EXTENSION_TRIGGER_MENU, p_ext, i );
+}
+
+/** Can this extension only be triggered but not activated?
+    Not compatible with HasMenu */
+#define extension_TriggerOnly( mgr, ext ) \
+        __extension_GetBool( mgr, ext, EXTENSION_TRIGGER_ONLY, false )
+
+
+/*****************************************************************************
+ * Extension dialogs
+ *****************************************************************************/
+
+typedef struct extension_dialog_t extension_dialog_t;
+typedef struct extension_widget_t extension_widget_t;
+
+/// User interface event types
+typedef enum
+{
+    EXTENSION_EVENT_CLICK,       ///< Click on a widget: data = widget
+    EXTENSION_EVENT_CLOSE,       ///< Close the dialog: no data
+    // EXTENSION_EVENT_SELECTION_CHANGED,
+    // EXTENSION_EVENT_TEXT_CHANGED,
+} extension_dialog_event_e;
+
+/// Command to pass to the extension dialog owner
+typedef struct
+{
+    extension_dialog_t *p_dlg;      ///< Destination dialog
+    extension_dialog_event_e event; ///< Event, @see extension_dialog_event_e
+    void *p_data;                   ///< Opaque data to send
+} extension_dialog_command_t;
+
+
+/// Dialog descriptor for extensions
+struct extension_dialog_t
+{
+    vlc_object_t *p_object;      ///< Owner object (callback on "dialog-event")
+
+    char *psz_title;             ///< Title for the Dialog (in TitleBar)
+    int i_width;                 ///< Width hint in pixels (may be discarded)
+    int i_height;                ///< Height hint in pixels (may be discarded)
+
+    DECL_ARRAY(extension_widget_t*) widgets; ///< Widgets owned by the dialog
+
+    bool b_hide;                 ///< Hide this dialog (!b_hide shows)
+    bool b_kill;                 ///< Kill this dialog
+
+    void *p_sys;                 ///< Dialog private pointer
+    void *p_sys_intf;            ///< GUI private pointer
+    vlc_mutex_t lock;            ///< Dialog mutex
+    vlc_cond_t cond;             ///< Signaled == UI is done working on the dialog
+};
+
+/** Send a command to an Extension dialog
+ * @param p_dialog The dialog
+ * @param event @see extension_dialog_event_e for a list of possible events
+ * @param data Optional opaque data,  @see extension_dialog_event_e
+ * @return VLC error code
+ **/
+static inline int extension_DialogCommand( extension_dialog_t* p_dialog,
+                                           extension_dialog_event_e event,
+                                           void *data )
+{
+    extension_dialog_command_t command;
+    command.p_dlg = p_dialog;
+    command.event = event;
+    command.p_data = data;
+    var_SetAddress( p_dialog->p_object, "dialog-event", &command );
+    return VLC_SUCCESS;
+}
+
+/** Close the dialog
+ * @param dlg The dialog
+ **/
+#define extension_DialogClosed( dlg ) \
+        extension_DialogCommand( dlg, EXTENSION_EVENT_CLOSE, NULL )
+
+/** Forward a click on a widget
+ * @param dlg The dialog
+ * @param wdg The widget (button, ...)
+ **/
+#define extension_WidgetClicked( dlg, wdg ) \
+        extension_DialogCommand( dlg, EXTENSION_EVENT_CLICK, wdg )
+
+/// Widget types
+typedef enum
+{
+    EXTENSION_WIDGET_LABEL,      ///< Non editable text label
+    EXTENSION_WIDGET_BUTTON,     ///< Clickable button
+    EXTENSION_WIDGET_IMAGE,      ///< Image label (psz_text is local URI)
+    EXTENSION_WIDGET_HTML,       ///< HTML or rich text area (non editable)
+    EXTENSION_WIDGET_TEXT_FIELD, ///< Editable text line for user input
+    EXTENSION_WIDGET_PASSWORD,   ///< Editable password input (******)
+    EXTENSION_WIDGET_DROPDOWN,   ///< Drop-down box
+    EXTENSION_WIDGET_LIST,       ///< Vertical list box (of strings)
+    EXTENSION_WIDGET_CHECK_BOX,  ///< Checkable box with label
+} extension_widget_type_e;
+
+/// Widget descriptor for extensions
+struct extension_widget_t
+{
+    /* All widgets */
+    extension_widget_type_e type; ///< Type of the widget
+    char *psz_text;               ///< Text. May be NULL or modified by the UI
+
+    /* Drop-down & List widgets */
+    struct extension_widget_value_t {
+        int i_id;          ///< Identifier for the extension module
+                           // (weird behavior may occur if not unique)
+        char *psz_text;    ///< String value
+        bool b_selected;   ///< True if this item is selected
+        struct extension_widget_value_t *p_next; ///< Next value or NULL
+    } *p_values;                  ///< Chained list of values (Drop-down/List)
+
+    /* Check-box */
+    bool b_checked;               ///< Is this entry checked
+
+    /* Layout */
+    int i_row;                    ///< Row in the grid
+    int i_column;                 ///< Column in the grid
+    int i_horiz_span;             ///< Horizontal size of the object
+    int i_vert_span;              ///< Vertical size of the object
+    int i_width;                  ///< Width hint
+    int i_height;                 ///< Height hint
+    bool b_hide;                  ///< Hide this widget (make it invisible)
+
+    /* Orders */
+    bool b_kill;                  ///< Destroy this widget
+    bool b_update;                ///< Update this widget
+
+    /* Misc */
+    void *p_sys;                  ///< Reserved for the extension manager
+    void *p_sys_intf;             ///< Reserved for the UI, but:
+                                  // NULL means the UI has destroyed the widget
+                                  // or has not created it yet
+    extension_dialog_t *p_dialog; ///< Parent dialog
+};
+
+VLC_EXPORT(int, dialog_ExtensionUpdate, (vlc_object_t*, extension_dialog_t *));
+#define dialog_ExtensionUpdate(o, d) dialog_ExtensionUpdate(VLC_OBJECT(o), d)
+
+#endif /* VLC_EXTENSIONS_H */
+