Auto merge of #7761 - fiji-flo:input_caret, r=pcwalton

display input caret for textarea. fixes #7758

This adds the input caret for textareas. Although, it does not handle multiline textareas correctly. The caret gets displayed for each line.

I'll look into that but that will take more time. Some feedback on this small patch would be appreciated though.

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components/layout/text.rs

@@ -431,9 +431,19 @@ fn split_first_fragment_at_newline_if_necessary(fragments: &mut LinkedList<Fragm
 
             string_before =
                 unscanned_text_fragment_info.text[..(position + 1)].to_owned();
-            insertion_point_before = unscanned_text_fragment_info.insertion_point;
             unscanned_text_fragment_info.text =
                 unscanned_text_fragment_info.text[(position + 1)..].to_owned().into_boxed_str();
+            let offset = CharIndex(string_before.char_indices().count() as isize);
+            match unscanned_text_fragment_info.insertion_point {
+                Some(insertion_point) if insertion_point >= offset => {
+                    insertion_point_before = None;
+                    unscanned_text_fragment_info.insertion_point = Some(insertion_point - offset);
+                }
+                Some(_) | None => {
+                    insertion_point_before = unscanned_text_fragment_info.insertion_point;
+                    unscanned_text_fragment_info.insertion_point = None;
+                }
+            };
         }
         first_fragment.transform(first_fragment.border_box.size,
                                  SpecificFragmentInfo::UnscannedText(

components/layout/wrapper.rs

@@ -71,7 +71,7 @@ use style::node::TElementAttributes;
 use style::properties::ComputedValues;
 use style::properties::{PropertyDeclaration, PropertyDeclarationBlock};
 use url::Url;
-use util::str::is_whitespace;
+use util::str::{is_whitespace, search_index};
 
 /// A wrapper so that layout can access only the methods that it should have access to. Layout must
 /// only ever see these and must never see instances of `LayoutJS`.
@@ -918,24 +918,17 @@ impl<'ln> ThreadSafeLayoutNode<'ln> {
         let this = unsafe {
             self.get_jsmanaged()
         };
-        let input = this.downcast();
-        if let Some(input) = input {
-            let insertion_point = unsafe {
-                input.get_insertion_point_for_layout()
-            };
-            if let Some(insertion_point) = insertion_point {
-                let text = unsafe {
-                    input.get_value_for_layout()
-                };
 
-                let mut character_count = 0;
-                for (character_index, _) in text.char_indices() {
-                    if character_index == insertion_point.index {
-                        return Some(CharIndex(character_count))
+        if let Some(area) = this.downcast::<HTMLTextAreaElement>() {
+            let insertion_point = unsafe { area.get_absolute_insertion_point_for_layout() };
+            let text = unsafe { area.get_value_for_layout() };
+            return Some(CharIndex(search_index(insertion_point, text.char_indices())));
         }
-                    character_count += 1
-                }
-                return Some(CharIndex(character_count))
+        if let Some(input) = this.downcast::<HTMLInputElement>() {
+            let insertion_point = unsafe { input.get_insertion_point_for_layout() };
+            if let Some(insertion_point) = insertion_point {
+                let text = unsafe { input.get_value_for_layout() };
+                return Some(CharIndex(search_index(insertion_point.index, text.char_indices())));
             }
         }
         None

components/script/dom/htmltextareaelement.rs

@@ -46,6 +46,8 @@ pub struct HTMLTextAreaElement {
 pub trait LayoutHTMLTextAreaElementHelpers {
     #[allow(unsafe_code)]
     unsafe fn get_value_for_layout(self) -> String;
+    #[allow(unsafe_code)]
+    unsafe fn get_absolute_insertion_point_for_layout(self) -> usize;
 }
 
 pub trait RawLayoutHTMLTextAreaElementHelpers {
@@ -61,6 +63,12 @@ impl LayoutHTMLTextAreaElementHelpers for LayoutJS<HTMLTextAreaElement> {
     unsafe fn get_value_for_layout(self) -> String {
         (*self.unsafe_get()).textinput.borrow_for_layout().get_content()
     }
+
+    #[allow(unrooted_must_root)]
+    #[allow(unsafe_code)]
+    unsafe fn get_absolute_insertion_point_for_layout(self) -> usize {
+        (*self.unsafe_get()).textinput.borrow_for_layout().get_absolute_insertion_point()
+    }
 }
 
 impl<'a> RawLayoutHTMLTextAreaElementHelpers for &'a HTMLTextAreaElement {

components/script/textinput.rs

@@ -455,4 +455,14 @@ impl<T: ClipboardProvider> TextInput<T> {
         self.edit_point.line = min(self.edit_point.line, self.lines.len() - 1);
         self.edit_point.index = min(self.edit_point.index, self.current_line_length());
     }
+
+    pub fn get_absolute_insertion_point(&self) -> usize {
+        self.lines.iter().enumerate().fold(0, |acc, (i, val)| {
+            if i < self.edit_point.line {
+                acc + val.len() + 1 // +1 for the \n
+            } else {
+                acc
+            }
+        }) + self.edit_point.index
+    }
 }

components/util/str.rs

@@ -11,7 +11,7 @@ use std::borrow::ToOwned;
 use std::ffi::CStr;
 use std::iter::{Filter, Peekable};
 use std::ops::Deref;
-use std::str::{FromStr, Split, from_utf8};
+use std::str::{CharIndices, FromStr, Split, from_utf8};
 
 pub type DOMString = String;
 pub type StaticCharVec = &'static [char];
@@ -420,3 +420,16 @@ pub fn slice_chars(s: &str, begin: usize, end: usize) -> &str {
         (Some(a), Some(b)) => unsafe { s.slice_unchecked(a, b) }
     }
 }
+
+// searches a character index in CharIndices
+// returns indices.count if not found
+pub fn search_index(index: usize, indices: CharIndices) -> isize {
+    let mut character_count = 0;
+    for (character_index, _) in indices {
+        if character_index == index {
+            return character_count;
+        }
+        character_count += 1
+    }
+    character_count
+}

tests/unit/util/str.rs

@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use util::str::{split_html_space_chars, str_join};
+use util::str::{search_index, split_html_space_chars, str_join};
 
 
 #[test]
@@ -34,3 +34,15 @@ pub fn test_str_join_many() {
     let expected = "-alpha--beta-gamma-";
     assert_eq!(actual, expected);
 }
+
+#[test]
+pub fn test_search_index() {
+    let tuples = [("", 1, 0),
+                  ("foo", 8, 3),
+                  ("føo", 8, 3),
+                  ("foo", 2, 2),
+                  ("føo", 2, 3)];
+    for t in tuples.iter() {
+        assert_eq!(search_index(t.1, t.0.char_indices()), t.2);
+    };
+}