avm2: Implement TextField.maxChars

core/src/avm2/globals/flash/text/textfield.rs

@@ -1241,6 +1241,41 @@ pub fn set_scroll_h<'gc>(
     Ok(Value::Undefined)
 }
 
+pub fn max_chars<'gc>(
+    _activation: &mut Activation<'_, 'gc>,
+    this: Option<Object<'gc>>,
+    _args: &[Value<'gc>],
+) -> Result<Value<'gc>, Error<'gc>> {
+    if let Some(this) = this
+        .and_then(|this| this.as_display_object())
+        .and_then(|this| this.as_edit_text())
+    {
+        return Ok(this.max_chars().into());
+    }
+
+    Ok(Value::Undefined)
+}
+
+pub fn set_max_chars<'gc>(
+    activation: &mut Activation<'_, 'gc>,
+    this: Option<Object<'gc>>,
+    args: &[Value<'gc>],
+) -> Result<Value<'gc>, Error<'gc>> {
+    if let Some(this) = this
+        .and_then(|this| this.as_display_object())
+        .and_then(|this| this.as_edit_text())
+    {
+        let input = args
+            .get(0)
+            .cloned()
+            .unwrap_or(Value::Undefined)
+            .coerce_to_i32(activation)?;
+        this.set_max_chars(input, &mut activation.context);
+    }
+
+    Ok(Value::Undefined)
+}
+
 /// Construct `TextField`'s class.
 pub fn create_class<'gc>(mc: MutationContext<'gc, '_>) -> GcCell<'gc, Class<'gc>> {
     let class = Class::new(
@@ -1288,6 +1323,7 @@ pub fn create_class<'gc>(mc: MutationContext<'gc, '_>) -> GcCell<'gc, Class<'gc>
         ("length", Some(length), None),
         ("maxScrollH", Some(max_scroll_h), None),
         ("maxScrollV", Some(max_scroll_v), None),
+        ("maxChars", Some(max_chars), Some(set_max_chars)),
         ("multiline", Some(multiline), Some(set_multiline)),
         ("scrollH", Some(scroll_h), Some(set_scroll_h)),
         ("scrollV", Some(scroll_v), Some(set_scroll_v)),

core/src/display_object/edit_text.rs

@@ -133,6 +133,10 @@ pub struct EditTextData<'gc> {
     /// How many lines down the text is offset by. 1-based index.
     scroll: usize,
 
+    /// The limit of characters that can be manually input by the user.
+    /// Doesn't affect script-triggered modifications.
+    max_chars: i32,
+
     /// Flags indicating the text field's settings.
     flags: EditTextFlag,
 }
@@ -278,6 +282,7 @@ impl<'gc> EditText<'gc> {
                 hscroll: 0.0,
                 line_data,
                 scroll: 1,
+                max_chars: 0,
             },
         ));
 
@@ -1122,6 +1127,14 @@ impl<'gc> EditText<'gc> {
         self.0.write(context.gc_context).scroll = clamped;
     }
 
+    pub fn max_chars(self) -> i32 {
+        self.0.read().max_chars
+    }
+
+    pub fn set_max_chars(self, value: i32, context: &mut UpdateContext<'_, 'gc>) {
+        self.0.write(context.gc_context).max_chars = value;
+    }
+
     pub fn screen_position_to_index(self, position: (Twips, Twips)) -> Option<usize> {
         let text = self.0.read();
         let position = self.global_to_local(position);
@@ -1212,6 +1225,17 @@ impl<'gc> EditText<'gc> {
                     }
                 }
                 code if !(code as char).is_control() => {
+                    let can_insert = {
+                        let read = self.0.read();
+                        let max_chars = read.max_chars;
+                        if max_chars == 0 {
+                            true
+                        } else {
+                            let text_len = read.text_spans.text().len();
+                            text_len < max_chars.max(0) as usize
+                        }
+                    };
+                    if can_insert {
                         self.replace_text(
                             selection.start(),
                             selection.end(),
@@ -1225,6 +1249,7 @@ impl<'gc> EditText<'gc> {
                         );
                         changed = true;
                     }
+                }
                 _ => {}
             }