rkw6086
dbfa8bcd48
- expose command-monitor conversations and preserve visible agent transcripts - add bounded polling and a dedicated shell interrupt tool - improve direct-provider images, skills, tool history, and usage handling - package and brand Galaxy Control across releases, installers, persistence, and docs
Input Box
1. APIs of the Input Box
The input box is a child view named EditorView instantiated within TerminalView.
For the editor view to communicate with the terminal view, have the editor view send an action and register the action in the parent view.
For the terminal view to communicate with the editor view, the terminal view can directly access the editor view via a field in its struct. For it to input a newline, for example, it calls:
fn input_newline(&mut self, _: &(), ctx: &mut ViewContext<Self>) {
...
self.input.update(ctx, |input, ctx| input.insert(&'\n'.into(), ctx));
...
2. Editor
Buffer
The data structure that contains the text in the EditorView is the Buffer.
Its most commonly used API of the Buffer is chars_at(), which returns an iterator we can use to traverse characters from a certain point.
Under the hood, the buffer is a SumTree<Fragment>. Each Fragment has a Text. The Text consists of text which is an Arc<str> and runs which is a SumTree<Run>. A run describes how much space the fragment is taking.
Another useful API of Buffer is line_len(row_number) which gives you the length of a row number.
Indexing into the Buffer
We use Point and Offset to index into the buffer. Point is a 2-dimensional location with row and column within the Buffer. Offset is a 1-dimensional usize within the Buffer. You can easily convert Point and Anchor to Offset via to_offset(). Offset is useful for traversing through the characters without having to worry about changing row and column numbers.
DisplayPoints and DisplayMap
Another struct with row and column is the DisplayPoint. DisplayPoint is only relevant in EditorView and DisplayMap, but not the Buffer.
DisplayPoint describes the location in the DisplayMap. The DisplayMap describes how the points appear—the visual coordinate system. The Buffer has no concept of how it's being displayed and could in fact be displayed in multiple views.
The values of DisplayPoints and Points differ when code folding or softwrapping occurs. We can translate between the DisplayPoint and Point using the DisplayMap.
Selections and Cursors
The input box supports the multiple selections we are used to in VSCode. So our EditorView has a Vec<Selection>.
A Selection has a start anchor and an end anchor to denote its start and end position.
Selections and cursors are closely intertwined—wherever there is a selection, there is a cursor. A cursor on its own is just an empty selection where start==end. As such, there is always at least one Selection, with the first selection being the cursor.
Anchors
An Anchor is a bookmark into the text. It allows us to index for a relative position in the text even if its absolute position has changed. An Anchor can be converted to a DisplayPoint or a Point.
For example, imagine my cursor is between the characters 'l' and 'E' in 'PartialEq'. Say the absolute position is row 3 column 7:
Partial|Eq
Then, we add 10 characters:
Partial1234567890|Eq
The cursor's absolute position is now at row 3 column 17. To easily calculate this position, we can convert the Anchor to row 3 column 17.
AnchorBias::Left, AnchorBias::Right
The AnchorBias determines whether the cursor ends up on the right side or the left side of the inserted text. The above example is when AnchorBias is Right. AnchorBias::Left looks like this:
Partial|1234567890Eq
Anchors are most useful when we introduce collaborative editing, and it is important for users to know where they are typing in even when another user inserts text in the line they are on.