Module TreeView 

TreeView (Command)

RESPONSIBILITIES:

• Defines Tauri command handlers for TreeView operations from Sky frontend
• Bridges TreeView UI requests to TreeViewProvider
• Handles tree data fetching, expansion, selection, and refresh operations
• Manages tree view state persistence and restoration (stubs)

ARCHITECTURAL ROLE:

• Command module exposing TreeView functionality via Tauri IPC (#[command])
• Delegates to Environment’s TreeViewProvider via DI with Require() trait from MountainEnvironment
• Translates frontend requests to provider method calls with proper error mapping

COMMAND REFERENCE (Tauri IPC):

• GetTreeViewChildren: Fetch child items for a tree node (by ElementHandle, null for root)
• GetTreeViewItem: Get tree item metadata (label, icon, description) by handle
• OnTreeViewExpansionChanged: Notify when user expands/collapses a node (stub - trait method missing)
• OnTreeViewSelectionChanged: Notify when user selects/deselects tree items (stub - trait method missing)
• RefreshTreeView: Request tree view to refresh its data, optionally specific items
• RevealTreeViewItem: Request to reveal/focus a specific tree item in the UI
• PersistTreeView: Save tree view state (scroll position, expansion) (stub)
• RestoreTreeView: Restore previously saved tree view state (stub)

ERROR HANDLING:

• Returns Result<Value, String> with error strings sent to frontend
• Provider errors are logged with context and converted to error strings
• Missing trait methods return structured error indicating not implemented

PERFORMANCE:

• All commands are async and non-blocking
• Tree data fetching should be efficient; provider may cache results
• Refresh can target specific items to avoid full tree rebuild

VS CODE REFERENCE:

• vs/workbench/api/browser/mainThreadTreeViews.ts - main thread tree view API
• vs/workbench/api/common/extHostTreeViews.ts - extension host tree view API
• vs/workbench/contrib/files/browser/explorerView.ts - file explorer tree view
• vs/workbench/contrib/tree/browser/treeView.ts - generic tree view component

TODO:

• Implement OnTreeNodeExpanded and OnTreeSelectionChanged in TreeViewProvider trait
• Add tree view state persistence to ApplicationState
• Implement drag and drop support for tree items
• Add tree item validation and disabled states
• Support tree item tooltips and description rendering
• Implement tree item icon theming (light/dark)
• Add tree view column support (multi-column tree views)
• Support tree view title and description updates
• Implement tree view badge (count overlay) functionality
• Add tree view message handling for dynamic updates
• Support tree item context menu contributions
• Implement tree item editing (inline rename)
• Add tree view accessibility (ARIA labels, keyboard navigation)

MODULE CONTENTS:

• Tauri command functions (all #[command] pub async fn):
  • Data retrieval: GetTreeViewChildren, GetTreeViewItem
  • UI events: OnTreeViewExpansionChanged, OnTreeViewSelectionChanged
  • Management: RefreshTreeView, RevealTreeViewItem
  • State: PersistTreeView, RestoreTreeView

Functions

GetTreeViewChildren

A specific Tauri command handler for the UI to fetch the children of a tree view node. This handler dispatches to the correct provider (native or proxied).

GetTreeViewItem

Gets the tree item for a given tree element handle.

OnTreeViewExpansionChanged

Handles tree node expansion/collapse events.

OnTreeViewSelectionChanged

Handles tree selection changes.

PersistTreeView

Persists tree view state.

RefreshTreeView

Refreshes a tree view.

RestoreTreeView

Restores tree view state.

RevealTreeViewItem

Reveals a specific tree item.