Gui text box: fix formatted string memory reservation (flipperdevices…

…#3447)

* text box: reserve correct memory size to avoid reallocation
* Furi: change string reset behavior to release memory, prevent realloc call. Gui: fix NULL-ptr dereference in TextBox.

Co-authored-by: あく <alleteam@gmail.com>

applications/services/gui/modules/text_box.c

@@ -4,6 +4,9 @@
 #include <furi.h>
 #include <stdint.h>
 
+#define TEXT_BOX_MAX_SYMBOL_WIDTH (10)
+#define TEXT_BOX_LINE_WIDTH (120)
+
 struct TextBox {
     View* view;
 
@@ -78,13 +81,11 @@ static void text_box_insert_endline(Canvas* canvas, TextBoxModel* model) {
     const char* str = model->text;
     size_t line_num = 0;
 
-    const size_t text_width = 120;
-
     while(str[i] != '\0') {
         char symb = str[i++];
         if(symb != '\n') {
             size_t glyph_width = canvas_glyph_width(canvas, symb);
-            if(line_width + glyph_width > text_width) {
+            if(line_width + glyph_width > TEXT_BOX_LINE_WIDTH) {
                 line_num++;
                 line_width = 0;
                 furi_string_push_back(model->text_formatted, '\n');
@@ -116,6 +117,10 @@ static void text_box_insert_endline(Canvas* canvas, TextBoxModel* model) {
 static void text_box_view_draw_callback(Canvas* canvas, void* _model) {
     TextBoxModel* model = _model;
 
+    if(!model->text) {
+        return;
+    }
+
     canvas_clear(canvas);
     if(model->font == TextBoxFontText) {
         canvas_set_font(canvas, FontSecondary);
@@ -211,21 +216,24 @@ void text_box_reset(TextBox* text_box) {
             furi_string_set(model->text_formatted, "");
             model->font = TextBoxFontText;
             model->focus = TextBoxFocusStart;
+            model->formatted = false;
         },
         true);
 }
 
 void text_box_set_text(TextBox* text_box, const char* text) {
     furi_assert(text_box);
     furi_assert(text);
+    size_t str_length = strlen(text);
+    size_t formating_margin = str_length * TEXT_BOX_MAX_SYMBOL_WIDTH / TEXT_BOX_LINE_WIDTH;
 
     with_view_model(
         text_box->view,
         TextBoxModel * model,
         {
             model->text = text;
             furi_string_reset(model->text_formatted);
-            furi_string_reserve(model->text_formatted, strlen(text));
+            furi_string_reserve(model->text_formatted, str_length + formating_margin);
             model->formatted = false;
         },
         true);

furi/core/string.c

@@ -71,7 +71,8 @@ void furi_string_reserve(FuriString* s, size_t alloc) {
 }
 
 void furi_string_reset(FuriString* s) {
-    string_reset(s->string);
+    string_clear(s->string);
+    string_init(s->string);
 }
 
 void furi_string_swap(FuriString* v1, FuriString* v2) {