feat: Add basic text support on Unix (#362)

README.md

@@ -28,7 +28,7 @@ These are the libraries that implement platform accessibility APIs. The followin
 
 * The Windows adapter, which implements the UI Automation API, is available in [the `accesskit_windows` crate](https://crates.io/crates/accesskit_windows), in [the `platforms/windows` directory](https://github.com/AccessKit/accesskit/tree/main/platforms/windows). It doesn't yet support all possible widget types, but it can now be used to make real, non-trivial applications accessible. In particular, it supports both single-line and multi-line text edit controls, but not yet rich text.
 * The macOS adapter, which implements the Cocoa NSAccessibility protocol, is available in [the `accesskit_macos` crate](https://crates.io/crates/accesskit_macos), in [the `platforms/macos` directory](https://github.com/AccessKit/accesskit/tree/main/platforms/macos). It is roughly at feature parity with the Windows adapter, including support for text edit controls.
-* The Unix adapter, which implements the D-Bus-based AT-SPI protocol, is available in [the `accesskit_unix` crate](https://crates.io/crates/accesskit_unix), in [the `platforms/unix` directory](https://github.com/AccessKit/accesskit/tree/main/platforms/unix). This adapter doesn't yet fully support text edit controls. It is also not yet usable with the Orca screen reader, due to a keyboard input handling issue that we are working with the appropriate GNOME development teams to solve.
+* The Unix adapter, which implements the D-Bus-based AT-SPI protocol, is available in [the `accesskit_unix` crate](https://crates.io/crates/accesskit_unix), in [the `platforms/unix` directory](https://github.com/AccessKit/accesskit/tree/main/platforms/unix). This adapter also supports text edit controls. It is not yet fully usable with the Orca screen reader, due to a keyboard input handling issue that we are working with the appropriate GNOME development teams to solve.
 
 The following adapters are planned:
 

consumer/src/text.rs

@@ -248,6 +248,24 @@ impl<'a> Position<'a> {
         Range::new(self.root_node, self.inner, self.inner)
     }
 
+    pub fn to_global_usv_index(&self) -> usize {
+        let mut total_length = 0usize;
+        for node in self.root_node.inline_text_boxes() {
+            let node_text = node.data().value().unwrap();
+            if node.id() == self.inner.node.id() {
+                let character_lengths = node.data().character_lengths();
+                let slice_end = character_lengths[..self.inner.character_index]
+                    .iter()
+                    .copied()
+                    .map(usize::from)
+                    .sum::<usize>();
+                return total_length + node_text[..slice_end].chars().count();
+            }
+            total_length += node_text.chars().count();
+        }
+        panic!("invalid position")
+    }
+
     pub fn to_global_utf16_index(&self) -> usize {
         let mut total_length = 0usize;
         for node in self.root_node.inline_text_boxes() {
@@ -996,6 +1014,48 @@ impl<'a> Node<'a> {
         Some(Range::new(*self, pos.inner, end.inner))
     }
 
+    pub fn text_position_from_global_usv_index(&self, index: usize) -> Option<Position> {
+        let mut total_length = 0usize;
+        for node in self.inline_text_boxes() {
+            let node_text = node.data().value().unwrap();
+            let node_text_length = node_text.chars().count();
+            let new_total_length = total_length + node_text_length;
+            if index >= total_length && index < new_total_length {
+                let index = index - total_length;
+                let mut utf8_length = 0usize;
+                let mut usv_length = 0usize;
+                for (character_index, utf8_char_length) in
+                    node.data().character_lengths().iter().enumerate()
+                {
+                    let new_utf8_length = utf8_length + (*utf8_char_length as usize);
+                    let char_str = &node_text[utf8_length..new_utf8_length];
+                    let usv_char_length = char_str.chars().count();
+                    let new_usv_length = usv_length + usv_char_length;
+                    if index >= usv_length && index < new_usv_length {
+                        return Some(Position {
+                            root_node: *self,
+                            inner: InnerPosition {
+                                node,
+                                character_index,
+                            },
+                        });
+                    }
+                    utf8_length = new_utf8_length;
+                    usv_length = new_usv_length;
+                }
+                panic!("index out of range");
+            }
+            total_length = new_total_length;
+        }
+        if index == total_length {
+            return Some(Position {
+                root_node: *self,
+                inner: self.document_end(),
+            });
+        }
+        None
+    }
+
     pub fn text_position_from_global_utf16_index(&self, index: usize) -> Option<Position> {
         let mut total_length = 0usize;
         for node in self.inline_text_boxes() {
@@ -1691,6 +1751,31 @@ mod tests {
         }
     }
 
+    #[test]
+    fn to_global_usv_index() {
+        let tree = main_multiline_tree(None);
+        let state = tree.state();
+        let node = state.node_by_id(NodeId(1)).unwrap();
+
+        {
+            let range = node.document_range();
+            assert_eq!(range.start().to_global_usv_index(), 0);
+            assert_eq!(range.end().to_global_usv_index(), 97);
+        }
+
+        {
+            let range = node.document_range();
+            let pos = range.start().forward_to_line_end();
+            assert_eq!(pos.to_global_usv_index(), 38);
+            let pos = range.start().forward_to_line_start();
+            assert_eq!(pos.to_global_usv_index(), 38);
+            let pos = pos.forward_to_character_start();
+            assert_eq!(pos.to_global_usv_index(), 39);
+            let pos = pos.forward_to_line_start();
+            assert_eq!(pos.to_global_usv_index(), 55);
+        }
+    }
+
     #[test]
     fn to_global_utf16_index() {
         let tree = main_multiline_tree(None);
@@ -1781,6 +1866,85 @@ mod tests {
         assert!(node.line_range_from_index(6).is_none());
     }
 
+    #[test]
+    fn text_position_from_global_usv_index() {
+        let tree = main_multiline_tree(None);
+        let state = tree.state();
+        let node = state.node_by_id(NodeId(1)).unwrap();
+
+        {
+            let pos = node.text_position_from_global_usv_index(0).unwrap();
+            assert!(pos.is_document_start());
+        }
+
+        {
+            let pos = node.text_position_from_global_usv_index(17).unwrap();
+            let mut range = pos.to_degenerate_range();
+            range.set_end(pos.forward_to_character_end());
+            assert_eq!(range.text(), "\u{a0}");
+        }
+
+        {
+            let pos = node.text_position_from_global_usv_index(18).unwrap();
+            let mut range = pos.to_degenerate_range();
+            range.set_end(pos.forward_to_character_end());
+            assert_eq!(range.text(), "l");
+        }
+
+        {
+            let pos = node.text_position_from_global_usv_index(37).unwrap();
+            let mut range = pos.to_degenerate_range();
+            range.set_end(pos.forward_to_character_end());
+            assert_eq!(range.text(), " ");
+        }
+
+        {
+            let pos = node.text_position_from_global_usv_index(38).unwrap();
+            assert!(!pos.is_paragraph_start());
+            assert!(pos.is_line_start());
+            let mut range = pos.to_degenerate_range();
+            range.set_end(pos.forward_to_character_end());
+            assert_eq!(range.text(), "t");
+        }
+
+        {
+            let pos = node.text_position_from_global_usv_index(54).unwrap();
+            let mut range = pos.to_degenerate_range();
+            range.set_end(pos.forward_to_character_end());
+            assert_eq!(range.text(), "\n");
+        }
+
+        {
+            let pos = node.text_position_from_global_usv_index(55).unwrap();
+            assert!(pos.is_paragraph_start());
+            assert!(pos.is_line_start());
+            let mut range = pos.to_degenerate_range();
+            range.set_end(pos.forward_to_character_end());
+            assert_eq!(range.text(), "A");
+        }
+
+        for i in 94..=95 {
+            let pos = node.text_position_from_global_usv_index(i).unwrap();
+            let mut range = pos.to_degenerate_range();
+            range.set_end(pos.forward_to_character_end());
+            assert_eq!(range.text(), "\u{1f44d}\u{1f3fb}");
+        }
+
+        {
+            let pos = node.text_position_from_global_usv_index(96).unwrap();
+            let mut range = pos.to_degenerate_range();
+            range.set_end(pos.forward_to_character_end());
+            assert_eq!(range.text(), "\n");
+        }
+
+        {
+            let pos = node.text_position_from_global_usv_index(97).unwrap();
+            assert!(pos.is_document_end());
+        }
+
+        assert!(node.text_position_from_global_usv_index(98).is_none());
+    }
+
     #[test]
     fn text_position_from_global_utf16_index() {
         let tree = main_multiline_tree(None);