[FL-2627] Flipper applications: SDK, build and debug system (#1387)

* Added support for running applications from SD card (FAPs - Flipper Application Packages)
* Added plugin_dist target for fbt to build FAPs
* All apps of type FlipperAppType.EXTERNAL and FlipperAppType.PLUGIN are built as FAPs by default
* Updated VSCode configuration for new fbt features - re-deploy stock configuration to use them
* Added debugging support for FAPs with fbt debug & VSCode
* Added public firmware API with automated versioning

Co-authored-by: hedger <hedger@users.noreply.github.com>
Co-authored-by: SG <who.just.the.doctor@gmail.com>
Co-authored-by: あく <alleteam@gmail.com>

applications/services/dialogs/application.fam

@@ -0,0 +1,11 @@
+App(
+    appid="dialogs",
+    name="DialogsSrv",
+    apptype=FlipperAppType.SERVICE,
+    entry_point="dialogs_srv",
+    cdefines=["SRV_DIALOGS"],
+    requires=["gui"],
+    stack_size=1 * 1024,
+    order=40,
+    sdk_headers=["dialogs.h"],
+)

applications/services/dialogs/dialogs.c

@@ -0,0 +1,54 @@
+#include "dialogs/dialogs_message.h"
+#include "dialogs_i.h"
+#include "dialogs_api_lock.h"
+#include "dialogs_module_file_browser.h"
+#include "dialogs_module_message.h"
+
+void dialog_file_browser_set_basic_options(
+    DialogsFileBrowserOptions* options,
+    const char* extension,
+    const Icon* icon) {
+    options->extension = extension;
+    options->skip_assets = true;
+    options->icon = icon;
+    options->hide_ext = true;
+    options->item_loader_callback = NULL;
+    options->item_loader_context = NULL;
+}
+
+static DialogsApp* dialogs_app_alloc() {
+    DialogsApp* app = malloc(sizeof(DialogsApp));
+    app->message_queue = furi_message_queue_alloc(8, sizeof(DialogsAppMessage));
+
+    return app;
+}
+
+static void dialogs_app_process_message(DialogsApp* app, DialogsAppMessage* message) {
+    UNUSED(app);
+    switch(message->command) {
+    case DialogsAppCommandFileBrowser:
+        message->return_data->bool_value =
+            dialogs_app_process_module_file_browser(&message->data->file_browser);
+        break;
+    case DialogsAppCommandDialog:
+        message->return_data->dialog_value =
+            dialogs_app_process_module_message(&message->data->dialog);
+        break;
+    }
+    API_LOCK_UNLOCK(message->lock);
+}
+
+int32_t dialogs_srv(void* p) {
+    UNUSED(p);
+    DialogsApp* app = dialogs_app_alloc();
+    furi_record_create(RECORD_DIALOGS, app);
+
+    DialogsAppMessage message;
+    while(1) {
+        if(furi_message_queue_get(app->message_queue, &message, FuriWaitForever) == FuriStatusOk) {
+            dialogs_app_process_message(app, &message);
+        }
+    }
+
+    return 0;
+}

applications/services/dialogs/dialogs.h

@@ -0,0 +1,165 @@
+#pragma once
+#include <furi.h>
+#include <gui/canvas.h>
+#include "m-string.h"
+#include <gui/modules/file_browser.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/****************** COMMON ******************/
+
+#define RECORD_DIALOGS "dialogs"
+
+typedef struct DialogsApp DialogsApp;
+
+/****************** FILE BROWSER ******************/
+
+/**
+ * File browser dialog extra options
+ * @param extension file extension to be offered for selection
+ * @param skip_assets true - do not show assets folders
+ * @param icon file icon pointer, NULL for default icon
+ * @param hide_ext true - hide extensions for files
+ * @param item_loader_callback callback function for providing custom icon & entry name
+ * @param hide_ext callback context
+ */
+typedef struct {
+    const char* extension;
+    bool skip_assets;
+    const Icon* icon;
+    bool hide_ext;
+    FileBrowserLoadItemCallback item_loader_callback;
+    void* item_loader_context;
+} DialogsFileBrowserOptions;
+
+/**
+ * Initialize file browser dialog options
+ * and set default values
+ * @param options pointer to options structure
+ * @param extension file extension to filter
+ * @param icon file icon pointer, NULL for default icon
+ */
+void dialog_file_browser_set_basic_options(
+    DialogsFileBrowserOptions* options,
+    const char* extension,
+    const Icon* icon);
+
+/**
+ * Shows and processes the file browser dialog
+ * @param context api pointer
+ * @param result_path selected file path string pointer
+ * @param path preselected file path string pointer
+ * @param options file browser dialog extra options, may be null
+ * @return bool whether a file was selected
+ */
+bool dialog_file_browser_show(
+    DialogsApp* context,
+    string_ptr result_path,
+    string_ptr path,
+    const DialogsFileBrowserOptions* options);
+
+/****************** MESSAGE ******************/
+
+/**
+ * Message result type
+ */
+typedef enum {
+    DialogMessageButtonBack,
+    DialogMessageButtonLeft,
+    DialogMessageButtonCenter,
+    DialogMessageButtonRight,
+} DialogMessageButton;
+
+/**
+ * Message struct
+ */
+typedef struct DialogMessage DialogMessage;
+
+/**
+ * Allocate and fill message
+ * @return DialogMessage* 
+ */
+DialogMessage* dialog_message_alloc();
+
+/**
+ * Free message struct
+ * @param message message pointer
+ */
+void dialog_message_free(DialogMessage* message);
+
+/**
+ * Set message text
+ * @param message message pointer
+ * @param text text, can be NULL if you don't want to display the text
+ * @param x x position
+ * @param y y position
+ * @param horizontal horizontal alignment
+ * @param vertical vertical alignment
+ */
+void dialog_message_set_text(
+    DialogMessage* message,
+    const char* text,
+    uint8_t x,
+    uint8_t y,
+    Align horizontal,
+    Align vertical);
+
+/**
+ * Set message header
+ * @param message message pointer
+ * @param text text, can be NULL if you don't want to display the header
+ * @param x x position
+ * @param y y position
+ * @param horizontal horizontal alignment
+ * @param vertical vertical alignment
+ */
+void dialog_message_set_header(
+    DialogMessage* message,
+    const char* text,
+    uint8_t x,
+    uint8_t y,
+    Align horizontal,
+    Align vertical);
+
+/**
+ * Set message icon
+ * @param message message pointer
+ * @param icon icon pointer, can be NULL if you don't want to display the icon
+ * @param x x position
+ * @param y y position
+ */
+void dialog_message_set_icon(DialogMessage* message, const Icon* icon, uint8_t x, uint8_t y);
+
+/**
+ * Set message buttons text, button text can be NULL if you don't want to display and process some buttons
+ * @param message message pointer
+ * @param left left button text, can be NULL if you don't want to display the left button
+ * @param center center button text, can be NULL if you don't want to display the center button
+ * @param right right button text, can be NULL if you don't want to display the right button
+ */
+void dialog_message_set_buttons(
+    DialogMessage* message,
+    const char* left,
+    const char* center,
+    const char* right);
+
+/**
+ * Show message from filled struct
+ * @param context api pointer
+ * @param message message struct pointer to be shown
+ * @return DialogMessageButton type
+ */
+DialogMessageButton dialog_message_show(DialogsApp* context, const DialogMessage* message);
+
+/**
+ * Show SD error message (with question sign)
+ * @param context 
+ * @param error_text 
+ */
+void dialog_message_show_storage_error(DialogsApp* context, const char* error_text);
+
+#ifdef __cplusplus
+}
+#endif

applications/services/dialogs/dialogs_api.c

@@ -0,0 +1,78 @@
+#include "dialogs/dialogs_message.h"
+#include "dialogs_i.h"
+#include "dialogs_api_lock.h"
+#include "m-string.h"
+
+/****************** File browser ******************/
+
+bool dialog_file_browser_show(
+    DialogsApp* context,
+    string_ptr result_path,
+    string_ptr path,
+    const DialogsFileBrowserOptions* options) {
+    FuriApiLock lock = API_LOCK_INIT_LOCKED();
+    furi_check(lock != NULL);
+
+    DialogsAppData data = {
+        .file_browser = {
+            .extension = options ? options->extension : "",
+            .result_path = result_path,
+            .file_icon = options ? options->icon : NULL,
+            .hide_ext = options ? options->hide_ext : true,
+            .skip_assets = options ? options->skip_assets : true,
+            .preselected_filename = path,
+            .item_callback = options ? options->item_loader_callback : NULL,
+            .item_callback_context = options ? options->item_loader_context : NULL,
+        }};
+
+    DialogsAppReturn return_data;
+    DialogsAppMessage message = {
+        .lock = lock,
+        .command = DialogsAppCommandFileBrowser,
+        .data = &data,
+        .return_data = &return_data,
+    };
+
+    furi_check(
+        furi_message_queue_put(context->message_queue, &message, FuriWaitForever) == FuriStatusOk);
+    API_LOCK_WAIT_UNTIL_UNLOCK_AND_FREE(lock);
+
+    return return_data.bool_value;
+}
+
+/****************** Message ******************/
+
+DialogMessageButton dialog_message_show(DialogsApp* context, const DialogMessage* dialog_message) {
+    FuriApiLock lock = API_LOCK_INIT_LOCKED();
+    furi_check(lock != NULL);
+
+    DialogsAppData data = {
+        .dialog = {
+            .message = dialog_message,
+        }};
+
+    DialogsAppReturn return_data;
+    DialogsAppMessage message = {
+        .lock = lock,
+        .command = DialogsAppCommandDialog,
+        .data = &data,
+        .return_data = &return_data,
+    };
+
+    furi_check(
+        furi_message_queue_put(context->message_queue, &message, FuriWaitForever) == FuriStatusOk);
+    API_LOCK_WAIT_UNTIL_UNLOCK_AND_FREE(lock);
+
+    return return_data.dialog_value;
+}
+
+/****************** Storage error ******************/
+
+void dialog_message_show_storage_error(DialogsApp* context, const char* error_text) {
+    DialogMessage* message = dialog_message_alloc();
+    dialog_message_set_text(message, error_text, 88, 32, AlignCenter, AlignCenter);
+    dialog_message_set_icon(message, &I_SDQuestion_35x43, 5, 6);
+    dialog_message_set_buttons(message, "Back", NULL, NULL);
+    dialog_message_show(context, message);
+    dialog_message_free(message);
+}

applications/services/dialogs/dialogs_api_lock.h

@@ -0,0 +1,18 @@
+#pragma once
+
+typedef FuriEventFlag* FuriApiLock;
+
+#define API_LOCK_EVENT (1U << 0)
+
+#define API_LOCK_INIT_LOCKED() furi_event_flag_alloc();
+
+#define API_LOCK_WAIT_UNTIL_UNLOCK(_lock) \
+    furi_event_flag_wait(_lock, API_LOCK_EVENT, FuriFlagWaitAny, FuriWaitForever);
+
+#define API_LOCK_FREE(_lock) furi_event_flag_free(_lock);
+
+#define API_LOCK_UNLOCK(_lock) furi_event_flag_set(_lock, API_LOCK_EVENT);
+
+#define API_LOCK_WAIT_UNTIL_UNLOCK_AND_FREE(_lock) \
+    API_LOCK_WAIT_UNTIL_UNLOCK(_lock);             \
+    API_LOCK_FREE(_lock);

applications/services/dialogs/dialogs_i.h

@@ -0,0 +1,16 @@
+#pragma once
+#include "dialogs.h"
+#include "dialogs_message.h"
+#include "view_holder.h"
+#include <gui/modules/file_browser.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+struct DialogsApp {
+    FuriMessageQueue* message_queue;
+};
+
+#ifdef __cplusplus
+}
+#endif

applications/services/dialogs/dialogs_message.h

@@ -0,0 +1,50 @@
+#pragma once
+#include <furi.h>
+#include "dialogs_i.h"
+#include "dialogs_api_lock.h"
+#include "m-string.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct {
+    const char* extension;
+    bool skip_assets;
+    bool hide_ext;
+    const Icon* file_icon;
+    string_ptr result_path;
+    string_ptr preselected_filename;
+    FileBrowserLoadItemCallback item_callback;
+    void* item_callback_context;
+} DialogsAppMessageDataFileBrowser;
+
+typedef struct {
+    const DialogMessage* message;
+} DialogsAppMessageDataDialog;
+
+typedef union {
+    DialogsAppMessageDataFileBrowser file_browser;
+    DialogsAppMessageDataDialog dialog;
+} DialogsAppData;
+
+typedef union {
+    bool bool_value;
+    DialogMessageButton dialog_value;
+} DialogsAppReturn;
+
+typedef enum {
+    DialogsAppCommandFileBrowser,
+    DialogsAppCommandDialog,
+} DialogsAppCommand;
+
+typedef struct {
+    FuriApiLock lock;
+    DialogsAppCommand command;
+    DialogsAppData* data;
+    DialogsAppReturn* return_data;
+} DialogsAppMessage;
+
+#ifdef __cplusplus
+}
+#endif

applications/services/dialogs/dialogs_module_file_browser.c

@@ -0,0 +1,60 @@
+#include "dialogs_i.h"
+#include "dialogs_api_lock.h"
+#include "gui/modules/file_browser.h"
+
+typedef struct {
+    FuriApiLock lock;
+    bool result;
+} DialogsAppFileBrowserContext;
+
+static void dialogs_app_file_browser_back_callback(void* context) {
+    furi_assert(context);
+    DialogsAppFileBrowserContext* file_browser_context = context;
+    file_browser_context->result = false;
+    API_LOCK_UNLOCK(file_browser_context->lock);
+}
+
+static void dialogs_app_file_browser_callback(void* context) {
+    furi_assert(context);
+    DialogsAppFileBrowserContext* file_browser_context = context;
+    file_browser_context->result = true;
+    API_LOCK_UNLOCK(file_browser_context->lock);
+}
+
+bool dialogs_app_process_module_file_browser(const DialogsAppMessageDataFileBrowser* data) {
+    bool ret = false;
+    Gui* gui = furi_record_open(RECORD_GUI);
+
+    DialogsAppFileBrowserContext* file_browser_context =
+        malloc(sizeof(DialogsAppFileBrowserContext));
+    file_browser_context->lock = API_LOCK_INIT_LOCKED();
+
+    ViewHolder* view_holder = view_holder_alloc();
+    view_holder_attach_to_gui(view_holder, gui);
+    view_holder_set_back_callback(
+        view_holder, dialogs_app_file_browser_back_callback, file_browser_context);
+
+    FileBrowser* file_browser = file_browser_alloc(data->result_path);
+    file_browser_set_callback(
+        file_browser, dialogs_app_file_browser_callback, file_browser_context);
+    file_browser_configure(
+        file_browser, data->extension, data->skip_assets, data->file_icon, data->hide_ext);
+    file_browser_set_item_callback(file_browser, data->item_callback, data->item_callback_context);
+    file_browser_start(file_browser, data->preselected_filename);
+
+    view_holder_set_view(view_holder, file_browser_get_view(file_browser));
+    view_holder_start(view_holder);
+    API_LOCK_WAIT_UNTIL_UNLOCK(file_browser_context->lock);
+
+    ret = file_browser_context->result;
+
+    view_holder_stop(view_holder);
+    view_holder_free(view_holder);
+    file_browser_stop(file_browser);
+    file_browser_free(file_browser);
+    API_LOCK_FREE(file_browser_context->lock);
+    free(file_browser_context);
+    furi_record_close(RECORD_GUI);
+
+    return ret;
+}

applications/services/dialogs/dialogs_module_file_browser.h

@@ -0,0 +1,12 @@
+#pragma once
+#include "dialogs_message.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+bool dialogs_app_process_module_file_browser(const DialogsAppMessageDataFileBrowser* data);
+
+#ifdef __cplusplus
+}
+#endif

applications/services/dialogs/dialogs_module_message.c

@@ -0,0 +1,155 @@
+#include "dialogs_i.h"
+#include "dialogs_api_lock.h"
+#include <gui/modules/dialog_ex.h>
+
+typedef struct {
+    FuriApiLock lock;
+    DialogMessageButton result;
+} DialogsAppMessageContext;
+
+struct DialogMessage {
+    const char* header_text;
+    uint8_t header_text_x;
+    uint8_t header_text_y;
+    Align header_horizontal;
+    Align header_vertical;
+    const char* dialog_text;
+    uint8_t dialog_text_x;
+    uint8_t dialog_text_y;
+    Align dialog_text_horizontal;
+    Align dialog_text_vertical;
+    const Icon* icon;
+    uint8_t icon_x;
+    uint8_t icon_y;
+    const char* left_button_text;
+    const char* center_button_text;
+    const char* right_button_text;
+};
+
+static void dialogs_app_message_back_callback(void* context) {
+    furi_assert(context);
+    DialogsAppMessageContext* message_context = context;
+    message_context->result = DialogMessageButtonBack;
+    API_LOCK_UNLOCK(message_context->lock);
+}
+
+static void dialogs_app_message_callback(DialogExResult result, void* context) {
+    furi_assert(context);
+    DialogsAppMessageContext* message_context = context;
+    switch(result) {
+    case DialogExResultLeft:
+        message_context->result = DialogMessageButtonLeft;
+        break;
+    case DialogExResultRight:
+        message_context->result = DialogMessageButtonRight;
+        break;
+    case DialogExResultCenter:
+        message_context->result = DialogMessageButtonCenter;
+        break;
+    default:
+        break;
+    }
+    API_LOCK_UNLOCK(message_context->lock);
+}
+
+DialogMessageButton dialogs_app_process_module_message(const DialogsAppMessageDataDialog* data) {
+    DialogMessageButton ret = DialogMessageButtonBack;
+    Gui* gui = furi_record_open(RECORD_GUI);
+    const DialogMessage* message = data->message;
+    DialogsAppMessageContext* message_context = malloc(sizeof(DialogsAppMessageContext));
+    message_context->lock = API_LOCK_INIT_LOCKED();
+
+    ViewHolder* view_holder = view_holder_alloc();
+    view_holder_attach_to_gui(view_holder, gui);
+    view_holder_set_back_callback(view_holder, dialogs_app_message_back_callback, message_context);
+
+    DialogEx* dialog_ex = dialog_ex_alloc();
+    dialog_ex_set_result_callback(dialog_ex, dialogs_app_message_callback);
+    dialog_ex_set_context(dialog_ex, message_context);
+    dialog_ex_set_header(
+        dialog_ex,
+        message->header_text,
+        message->header_text_x,
+        message->header_text_y,
+        message->header_horizontal,
+        message->header_vertical);
+    dialog_ex_set_text(
+        dialog_ex,
+        message->dialog_text,
+        message->dialog_text_x,
+        message->dialog_text_y,
+        message->dialog_text_horizontal,
+        message->dialog_text_vertical);
+    dialog_ex_set_icon(dialog_ex, message->icon_x, message->icon_y, message->icon);
+    dialog_ex_set_left_button_text(dialog_ex, message->left_button_text);
+    dialog_ex_set_center_button_text(dialog_ex, message->center_button_text);
+    dialog_ex_set_right_button_text(dialog_ex, message->right_button_text);
+
+    view_holder_set_view(view_holder, dialog_ex_get_view(dialog_ex));
+    view_holder_start(view_holder);
+    API_LOCK_WAIT_UNTIL_UNLOCK(message_context->lock);
+
+    ret = message_context->result;
+
+    view_holder_stop(view_holder);
+    view_holder_free(view_holder);
+    dialog_ex_free(dialog_ex);
+    API_LOCK_FREE(message_context->lock);
+    free(message_context);
+    furi_record_close(RECORD_GUI);
+
+    return ret;
+}
+
+DialogMessage* dialog_message_alloc() {
+    DialogMessage* message = malloc(sizeof(DialogMessage));
+    return message;
+}
+
+void dialog_message_free(DialogMessage* message) {
+    free(message);
+}
+
+void dialog_message_set_text(
+    DialogMessage* message,
+    const char* text,
+    uint8_t x,
+    uint8_t y,
+    Align horizontal,
+    Align vertical) {
+    message->dialog_text = text;
+    message->dialog_text_x = x;
+    message->dialog_text_y = y;
+    message->dialog_text_horizontal = horizontal;
+    message->dialog_text_vertical = vertical;
+}
+
+void dialog_message_set_header(
+    DialogMessage* message,
+    const char* text,
+    uint8_t x,
+    uint8_t y,
+    Align horizontal,
+    Align vertical) {
+    message->header_text = text;
+    message->header_text_x = x;
+    message->header_text_y = y;
+    message->header_horizontal = horizontal;
+    message->header_vertical = vertical;
+}
+
+void dialog_message_set_icon(DialogMessage* message, const Icon* icon, uint8_t x, uint8_t y) {
+    message->icon = icon;
+    message->icon_x = x;
+    message->icon_y = y;
+}
+
+void dialog_message_set_buttons(
+    DialogMessage* message,
+    const char* left,
+    const char* center,
+    const char* right) {
+    message->left_button_text = left;
+    message->center_button_text = center;
+    message->right_button_text = right;
+}

applications/services/dialogs/dialogs_module_message.h

@@ -0,0 +1,12 @@
+#pragma once
+#include "dialogs_message.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+DialogMessageButton dialogs_app_process_module_message(const DialogsAppMessageDataDialog* data);
+
+#ifdef __cplusplus
+}
+#endif

applications/services/dialogs/view_holder.c

@@ -0,0 +1,150 @@
+#include "view_holder.h"
+#include <gui/view_i.h>
+
+#define TAG "ViewHolder"
+
+struct ViewHolder {
+    View* view;
+    ViewPort* view_port;
+    Gui* gui;
+
+    FreeCallback free_callback;
+    void* free_context;
+
+    BackCallback back_callback;
+    void* back_context;
+
+    uint8_t ongoing_input;
+};
+
+static void view_holder_draw_callback(Canvas* canvas, void* context);
+static void view_holder_input_callback(InputEvent* event, void* context);
+
+ViewHolder* view_holder_alloc() {
+    ViewHolder* view_holder = malloc(sizeof(ViewHolder));
+
+    view_holder->view_port = view_port_alloc();
+    view_port_draw_callback_set(view_holder->view_port, view_holder_draw_callback, view_holder);
+    view_port_input_callback_set(view_holder->view_port, view_holder_input_callback, view_holder);
+    view_port_enabled_set(view_holder->view_port, false);
+
+    return view_holder;
+}
+
+void view_holder_free(ViewHolder* view_holder) {
+    furi_assert(view_holder);
+
+    if(view_holder->gui) {
+        gui_remove_view_port(view_holder->gui, view_holder->view_port);
+    }
+
+    view_port_free(view_holder->view_port);
+
+    if(view_holder->free_callback) {
+        view_holder->free_callback(view_holder->free_context);
+    }
+
+    free(view_holder);
+}
+
+void view_holder_set_view(ViewHolder* view_holder, View* view) {
+    furi_assert(view_holder);
+    if(view_holder->view) {
+        view_set_update_callback(view_holder->view, NULL);
+        view_set_update_callback_context(view_holder->view, NULL);
+    }
+
+    view_holder->view = view;
+
+    if(view_holder->view) {
+        view_set_update_callback(view_holder->view, view_holder_update);
+        view_set_update_callback_context(view_holder->view, view_holder);
+    }
+}
+
+void view_holder_set_free_callback(
+    ViewHolder* view_holder,
+    FreeCallback free_callback,
+    void* free_context) {
+    furi_assert(view_holder);
+    view_holder->free_callback = free_callback;
+    view_holder->free_context = free_context;
+}
+
+void* view_holder_get_free_context(ViewHolder* view_holder) {
+    return view_holder->free_context;
+}
+
+void view_holder_set_back_callback(
+    ViewHolder* view_holder,
+    BackCallback back_callback,
+    void* back_context) {
+    furi_assert(view_holder);
+    view_holder->back_callback = back_callback;
+    view_holder->back_context = back_context;
+}
+
+void view_holder_attach_to_gui(ViewHolder* view_holder, Gui* gui) {
+    furi_assert(gui);
+    furi_assert(view_holder);
+    view_holder->gui = gui;
+    gui_add_view_port(gui, view_holder->view_port, GuiLayerFullscreen);
+}
+
+void view_holder_start(ViewHolder* view_holder) {
+    view_port_enabled_set(view_holder->view_port, true);
+}
+
+void view_holder_stop(ViewHolder* view_holder) {
+    while(view_holder->ongoing_input) furi_delay_tick(1);
+    view_port_enabled_set(view_holder->view_port, false);
+}
+
+void view_holder_update(View* view, void* context) {
+    furi_assert(view);
+    furi_assert(context);
+
+    ViewHolder* view_holder = context;
+    if(view == view_holder->view) {
+        view_port_update(view_holder->view_port);
+    }
+}
+
+static void view_holder_draw_callback(Canvas* canvas, void* context) {
+    ViewHolder* view_holder = context;
+    if(view_holder->view) {
+        view_draw(view_holder->view, canvas);
+    }
+}
+
+static void view_holder_input_callback(InputEvent* event, void* context) {
+    ViewHolder* view_holder = context;
+
+    uint8_t key_bit = (1 << event->key);
+    if(event->type == InputTypePress) {
+        view_holder->ongoing_input |= key_bit;
+    } else if(event->type == InputTypeRelease) {
+        view_holder->ongoing_input &= ~key_bit;
+    } else if(!(view_holder->ongoing_input & key_bit)) {
+        FURI_LOG_W(
+            TAG,
+            "non-complementary input, discarding key: %s, type: %s",
+            input_get_key_name(event->key),
+            input_get_type_name(event->type));
+        return;
+    }
+
+    bool is_consumed = false;
+
+    if(view_holder->view) {
+        is_consumed = view_input(view_holder->view, event);
+    }
+
+    if(!is_consumed && event->type == InputTypeShort) {
+        if(event->key == InputKeyBack) {
+            if(view_holder->back_callback) {
+                view_holder->back_callback(view_holder->back_context);
+            }
+        }
+    }
+}

applications/services/dialogs/view_holder.h

@@ -0,0 +1,98 @@
+#pragma once
+
+#include <gui/view.h>
+#include <gui/gui.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct ViewHolder ViewHolder;
+
+/** 
+ * @brief Free callback type
+ */
+typedef void (*FreeCallback)(void* free_context);
+
+/** 
+ * @brief Back callback type
+ * @warning comes from GUI thread
+ */
+typedef void (*BackCallback)(void* back_context);
+
+/**
+ * @brief Allocate ViewHolder
+ * @return pointer to ViewHolder instance
+ */
+ViewHolder* view_holder_alloc();
+
+/**
+ * @brief Free ViewHolder and call Free callback
+ * @param view_holder pointer to ViewHolder
+ */
+void view_holder_free(ViewHolder* view_holder);
+
+/**
+ * @brief Set view for ViewHolder
+ * 
+ * @param view_holder ViewHolder instance
+ * @param view View instance
+ */
+void view_holder_set_view(ViewHolder* view_holder, View* view);
+
+/**
+ * @brief Set Free callback
+ * 
+ * @param view_holder ViewHolder instance
+ * @param free_callback callback pointer
+ * @param free_context callback context
+ */
+void view_holder_set_free_callback(
+    ViewHolder* view_holder,
+    FreeCallback free_callback,
+    void* free_context);
+
+/**
+ * @brief Free callback context getter. Useful if your Free callback is a module destructor, so you can get an instance of the module using this method.
+ * 
+ * @param view_holder ViewHolder instance
+ * @return void* free callback context
+ */
+void* view_holder_get_free_context(ViewHolder* view_holder);
+
+void view_holder_set_back_callback(
+    ViewHolder* view_holder,
+    BackCallback back_callback,
+    void* back_context);
+
+/**
+ * @brief Attach ViewHolder to GUI
+ * 
+ * @param view_holder ViewHolder instance
+ * @param gui GUI instance to attach to
+ */
+void view_holder_attach_to_gui(ViewHolder* view_holder, Gui* gui);
+
+/**
+ * @brief Enable view processing
+ * 
+ * @param view_holder 
+ */
+void view_holder_start(ViewHolder* view_holder);
+
+/**
+ * @brief Disable view processing
+ * 
+ * @param view_holder 
+ */
+void view_holder_stop(ViewHolder* view_holder);
+
+/** View Update Handler
+ * @param view, View Instance
+ * @param context, ViewHolder instance
+ */
+void view_holder_update(View* view, void* context);
+
+#ifdef __cplusplus
+}
+#endif