Auto merge of #25447 - teapotd:form-validation, r=jdm

Form constraint validation

It's almost done, there are few things remaining:

- ~Range underflow, range overflow and step mismatch implementation require #25405~
- ~There are some test failures due to missing DOM parts (#25003)~
- ~`pattern` attribute uses JS regexp syntax. Currently I used regex crate, but it's probably incompatible. Should we use SpiderMonkey's regexp via jsapi?~
- Currently validation errors are reported using `println!`. Are there any better options?
- ~["While the user interface is representing input that the user agent cannot convert to punycode, the control is suffering from bad input."](https://html.spec.whatwg.org/multipage/#e-mail-state-(type%3Demail)%3Asuffering-from-bad-input)~

r? @jdm

---
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #11444
- [x] There are tests for these changes

1 files changed, 11 insertions, 0 deletions

diff --git a/components/script/textinput.rs b/components/script/textinput.rs
index bc4c1c4a6cb..623085ccd19 100644
--- a/components/script/textinput.rs
+++ b/components/script/textinput.rs
@@ -184,6 +184,9 @@ pub struct TextInput<T: ClipboardProvider> {
     /// <https://html.spec.whatwg.org/multipage/#attr-fe-maxlength>
     max_length: Option<UTF16CodeUnits>,
     min_length: Option<UTF16CodeUnits>,
+
+    /// Was last change made by set_content?
+    was_last_change_by_set_content: bool,
 }
 
 /// Resulting action to be taken by the owner of a text input that is handling an event.
@@ -269,6 +272,7 @@ impl<T: ClipboardProvider> TextInput<T> {
             max_length: max_length,
             min_length: min_length,
             selection_direction: selection_direction,
+            was_last_change_by_set_content: true,
         };
         i.set_content(initial);
         i
@@ -300,6 +304,11 @@ impl<T: ClipboardProvider> TextInput<T> {
         self.min_length = length;
     }
 
+    /// Was last edit made by set_content?
+    pub fn was_last_change_by_set_content(&self) -> bool {
+        self.was_last_change_by_set_content
+    }
+
     /// Remove a character at the current editing point
     pub fn delete_char(&mut self, dir: Direction) {
         if self.selection_origin.is_none() || self.selection_origin == Some(self.edit_point) {
@@ -496,6 +505,7 @@ impl<T: ClipboardProvider> TextInput<T> {
         };
 
         self.lines = new_lines;
+        self.was_last_change_by_set_content = false;
         self.clear_selection();
         self.assert_ok_selection();
     }
@@ -1035,6 +1045,7 @@ impl<T: ClipboardProvider> TextInput<T> {
             vec![content]
         };
 
+        self.was_last_change_by_set_content = true;
         self.edit_point = self.edit_point.constrain_to(&self.lines);
 
         if let Some(origin) = self.selection_origin {