book: Extend memory management chapter

Author: Hofer-Julian

book/listings/Cargo.toml

@@ -102,6 +102,10 @@ path = "g_object_memory_management/3/main.rs"
 name = "g_object_memory_management_4"
 path = "g_object_memory_management/4/main.rs"
 
+[[bin]]
+name = "g_object_memory_management_5"
+path = "g_object_memory_management/5/main.rs"
+
 # g_object_properties
 [[bin]]
 name = "g_object_properties_1"

book/listings/g_object_memory_management/1/main.rs

@@ -1,8 +1,6 @@
-use std::cell::Cell;
-use std::rc::Rc;
-
 use gtk::prelude::*;
-use gtk::{self, glib, Application, ApplicationWindow, Button, Orientation};
+use gtk::{glib, Application, ApplicationWindow, Button};
+use std::cell::Cell;
 
 const APP_ID: &str = "org.gtk_rs.GObjectMemoryManagement1";
 
@@ -16,7 +14,9 @@ fn main() -> glib::ExitCode {
     // Run the application
     app.run()
 }
-fn build_ui(app: &Application) {
+
+// ANCHOR: build_ui
+fn build_ui(application: &Application) {
     // Create two buttons
     let button_increase = Button::builder()
         .label("Increase")
@@ -25,38 +25,22 @@ fn build_ui(app: &Application) {
         .margin_start(12)
         .margin_end(12)
         .build();
-    let button_decrease = Button::builder()
-        .label("Decrease")
-        .margin_top(12)
-        .margin_bottom(12)
-        .margin_start(12)
-        .margin_end(12)
-        .build();
 
-    // ANCHOR: callback
-    // Reference-counted object with inner-mutability
-    let number = Rc::new(Cell::new(0));
+    // A mutable integer
+    let number = Cell::new(0);
 
-    // Connect callbacks, when a button is clicked `number` will be changed
-    let number_copy = number.clone();
-    button_increase.connect_clicked(move |_| number_copy.set(number_copy.get() + 1));
-    button_decrease.connect_clicked(move |_| number.set(number.get() - 1));
-    // ANCHOR_END: callback
-
-    // Add buttons to `gtk_box`
-    let gtk_box = gtk::Box::builder()
-        .orientation(Orientation::Vertical)
-        .build();
-    gtk_box.append(&button_increase);
-    gtk_box.append(&button_decrease);
+    // Connect callbacks
+    // When a button is clicked, `number` should be changed
+    button_increase.connect_clicked(move |_| number.set(number.get() + 1));
 
     // Create a window
     let window = ApplicationWindow::builder()
-        .application(app)
+        .application(application)
         .title("My GTK App")
-        .child(&gtk_box)
+        .child(&button_increase)
         .build();
 
     // Present the window
     window.present();
 }
+// ANCHOR_END: build_ui

book/listings/g_object_memory_management/2/main.rs

@@ -1,7 +1,6 @@
 use std::cell::Cell;
 use std::rc::Rc;
 
-use glib::clone;
 use gtk::prelude::*;
 use gtk::{self, glib, Application, ApplicationWindow, Button, Orientation};
 
@@ -34,17 +33,14 @@ fn build_ui(app: &Application) {
         .margin_end(12)
         .build();
 
-    // Reference-counted object with inner mutability
-    let number = Rc::new(Cell::new(0));
-    // Connect callbacks
-    // When a button is clicked, `number` will be changed
     // ANCHOR: callback
-    button_increase.connect_clicked(clone!(@strong number => move |_| {
-        number.set(number.get() + 1);
-    }));
-    button_decrease.connect_clicked(move |_| {
-        number.set(number.get() - 1);
-    });
+    // Reference-counted object with inner-mutability
+    let number = Rc::new(Cell::new(0));
+
+    // Connect callbacks, when a button is clicked `number` will be changed
+    let number_copy = number.clone();
+    button_increase.connect_clicked(move |_| number_copy.set(number_copy.get() + 1));
+    button_decrease.connect_clicked(move |_| number.set(number.get() - 1));
     // ANCHOR_END: callback
 
     // Add buttons to `gtk_box`

book/listings/g_object_memory_management/3/main.rs

@@ -17,7 +17,6 @@ fn main() -> glib::ExitCode {
     // Run the application
     app.run()
 }
-
 fn build_ui(app: &Application) {
     // Create two buttons
     let button_increase = Button::builder()
@@ -35,21 +34,17 @@ fn build_ui(app: &Application) {
         .margin_end(12)
         .build();
 
+    // Reference-counted object with inner mutability
     let number = Rc::new(Cell::new(0));
-
-    // ANCHOR: callback
     // Connect callbacks
-    // When a button is clicked, `number` and label of the other button will be changed
-    button_increase.connect_clicked(clone!(@weak number, @strong button_decrease =>
-        move |_| {
-            number.set(number.get() + 1);
-            button_decrease.set_label(&number.get().to_string());
-    }));
-    button_decrease.connect_clicked(clone!(@strong button_increase =>
-        move |_| {
-            number.set(number.get() - 1);
-            button_increase.set_label(&number.get().to_string());
+    // When a button is clicked, `number` will be changed
+    // ANCHOR: callback
+    button_increase.connect_clicked(clone!(@strong number => move |_| {
+        number.set(number.get() + 1);
     }));
+    button_decrease.connect_clicked(move |_| {
+        number.set(number.get() - 1);
+    });
     // ANCHOR_END: callback
 
     // Add buttons to `gtk_box`

book/listings/g_object_memory_management/4/main.rs

@@ -35,41 +35,36 @@ fn build_ui(app: &Application) {
         .margin_end(12)
         .build();
 
-    // Reference-counted object with inner mutability
     let number = Rc::new(Cell::new(0));
 
     // ANCHOR: callback
     // Connect callbacks
     // When a button is clicked, `number` and label of the other button will be changed
-    button_increase.connect_clicked(clone!(@weak number, @weak button_decrease =>
+    button_increase.connect_clicked(clone!(@weak number, @strong button_decrease =>
         move |_| {
             number.set(number.get() + 1);
             button_decrease.set_label(&number.get().to_string());
     }));
-    button_decrease.connect_clicked(clone!(@weak button_increase =>
+    button_decrease.connect_clicked(clone!(@strong button_increase =>
         move |_| {
             number.set(number.get() - 1);
             button_increase.set_label(&number.get().to_string());
     }));
     // ANCHOR_END: callback
 
-    // ANCHOR: box_append
     // Add buttons to `gtk_box`
     let gtk_box = gtk::Box::builder()
         .orientation(Orientation::Vertical)
         .build();
     gtk_box.append(&button_increase);
     gtk_box.append(&button_decrease);
-    // ANCHOR_END: box_append
 
-    // ANCHOR: window_child
     // Create a window
     let window = ApplicationWindow::builder()
         .application(app)
         .title("My GTK App")
         .child(&gtk_box)
         .build();
-    // ANCHOR_END: window_child
 
     // Present the window
     window.present();

book/listings/g_object_memory_management/5/main.rs

@@ -0,0 +1,76 @@
+use std::cell::Cell;
+use std::rc::Rc;
+
+use glib::clone;
+use gtk::prelude::*;
+use gtk::{self, glib, Application, ApplicationWindow, Button, Orientation};
+
+const APP_ID: &str = "org.gtk_rs.GObjectMemoryManagement5";
+
+fn main() -> glib::ExitCode {
+    // Create a new application
+    let app = Application::builder().application_id(APP_ID).build();
+
+    // Connect to "activate" signal of `app`
+    app.connect_activate(build_ui);
+
+    // Run the application
+    app.run()
+}
+
+fn build_ui(app: &Application) {
+    // Create two buttons
+    let button_increase = Button::builder()
+        .label("Increase")
+        .margin_top(12)
+        .margin_bottom(12)
+        .margin_start(12)
+        .margin_end(12)
+        .build();
+    let button_decrease = Button::builder()
+        .label("Decrease")
+        .margin_top(12)
+        .margin_bottom(12)
+        .margin_start(12)
+        .margin_end(12)
+        .build();
+
+    // Reference-counted object with inner mutability
+    let number = Rc::new(Cell::new(0));
+
+    // ANCHOR: callback
+    // Connect callbacks
+    // When a button is clicked, `number` and label of the other button will be changed
+    button_increase.connect_clicked(clone!(@weak number, @weak button_decrease =>
+        move |_| {
+            number.set(number.get() + 1);
+            button_decrease.set_label(&number.get().to_string());
+    }));
+    button_decrease.connect_clicked(clone!(@weak button_increase =>
+        move |_| {
+            number.set(number.get() - 1);
+            button_increase.set_label(&number.get().to_string());
+    }));
+    // ANCHOR_END: callback
+
+    // ANCHOR: box_append
+    // Add buttons to `gtk_box`
+    let gtk_box = gtk::Box::builder()
+        .orientation(Orientation::Vertical)
+        .build();
+    gtk_box.append(&button_increase);
+    gtk_box.append(&button_decrease);
+    // ANCHOR_END: box_append
+
+    // ANCHOR: window_child
+    // Create a window
+    let window = ApplicationWindow::builder()
+        .application(app)
+        .title("My GTK App")
+        .child(&gtk_box)
+        .build();
+    // ANCHOR_END: window_child
+
+    // Present the window
+    window.present();
+}