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Workflow

Saving a File with Save Participants

Intercepting a save event, allowing an extension to modify a file (e.g. formatting) before Mountain writes it to disk.

Saving a File with Save Participants

Explains the process of intercepting a save event, allowing an extension in Cocoon to modify a file (e.g. for formatting) before Mountain writes it to disk.

Data Flow

User presses Ctrl+S (editor is dirty)
  -> workbench.action.files.save command
  -> IEditorService.save()
  -> TextFileEditorModelManager.save()
  -> WorkingCopyFileService.runSaveParticipants()
  -> Gather ISaveParticipants
  -> ExtHostSaveParticipant.participate()
  -> Wind sends $participateInSave gRPC to Cocoon

Cocoon:
  -> ExtHostDocumentSaveParticipant fires onWillSaveTextDocument
  -> Prettier extension calculates formatting edits
  -> Extension returns Promise<TextEdit[]>
  -> All extensions resolve, edits collected
  -> Serialize TextEdits to DTOs
  -> Return array of TextEdit DTOs to Wind

Wind/UI:
  -> BulkEditService applies TextEdits to document model in memory
  -> TextFileEditorModelManager proceeds to save
  -> IFileService.writeFile()
  -> TauriDiskFileSystemProvider -> WriteFile Effect -> TauriInvoke

Mountain:
  -> FsWriter receives call
  -> tokio::fs::write(path, content)
  -> Success returned up the chain

Wind/UI:
  -> TextFileEditorModel no longer dirty
  -> UI removes filled-circle indicator from editor tab
  -> Save complete

Phase 1: User Action and Initial Save Trigger (Wind/Sky)

  1. User presses Ctrl+S in a dirty editor. workbench.action.files.save dispatched.
  2. IEditorService.save() identifies the active editor and calls save on its EditorInput.
  3. TextFileEditorModelManager does not immediately write to disk. It enters the Save Participants phase.
  4. Emits a willSave event, orchestrated by IWorkingCopyFileService.

Phase 2: Orchestration via Save Participants (Wind -> Cocoon -> Wind)

  1. WorkingCopyFileService.runSaveParticipants() gathers all registered ISaveParticipants. One is ExtHostSaveParticipant, responsible for communicating with extensions in Cocoon.
  2. Calls participate() on ExtHostSaveParticipant, which makes a $participateInSave gRPC request to Cocoon with the document URI and save reason.

Phase 3: Extension Execution (Cocoon)

  1. Cocoon’s gRPC server dispatches to ExtHostDocumentSaveParticipant.
  2. Service fires onWillSaveTextDocument event to all subscribed extensions.
  3. Prettier extension calculates formatting edits, returns Promise<TextEdit[]>.
  4. Service collects all results, serializes TextEdit objects to DTOs via TypeConverter, returns to Wind.

Phase 4: Applying Edits and Final Save (Wind -> Mountain -> Disk)

  1. gRPC call resolves with text edits from extensions.
  2. BulkEditService applies the TextEdits to the document model in memory. Editor content now reflects formatted code.
  3. TextFileEditorModelManager proceeds to call IFileService.writeFile().
  4. Save follows the same path as Opening a File (Workflow #2): IFileService -> TauriDiskFileSystemProvider -> WriteFile Effect -> TauriInvoke -> Mountain.
  5. tokio::fs::write(path, content) writes the formatted document to disk.
  6. TextFileEditorModel is no longer dirty. UI removes the dirty indicator.

Key Source Files

  • Wind/Source/Application/BulkEdit/Live.ts — bulk edit service
  • Wind/Source/Application/File/Live.ts — file service
  • Mountain/Source/FileSystem/ — filesystem providers

See Also

Air ← Echo →