Move source editor out of module (#12457)

* Update Copybara options in preparation for open-sourcing the source editor * Move files * Update paths * Remove source-editor module and checks for its existence * Explicitly mention CM6 license in files that contain code adapted from CM6 GitOrigin-RevId: 89b7cc2b409db01ad103198ccbd1b126ab56349b
2026-11-15 14:43:46 +01:00 · 2023-04-13 08:40:56 +00:00
parent 3f992f9453
commit 7f37ba737c
296 changed files with 33268 additions and 54 deletions
@@ -0,0 +1,157 @@
+import { BlockInfo, EditorView, ViewPlugin, ViewUpdate } from '@codemirror/view'
+import { throttle } from 'lodash'
+import customLocalStorage from '../../../infrastructure/local-storage'
+import {
+  EditorSelection,
+  StateEffect,
+  Text,
+  TransactionSpec,
+} from '@codemirror/state'
+import { toggleVisualEffect } from './visual/visual'
+
+const buildStorageKey = (docId: string) => `doc.position.${docId}`
+
+type LineInfo = {
+  first: BlockInfo
+  middle: BlockInfo
+}
+
+export const scrollPosition = ({
+  currentDoc: { doc_id: docId },
+}: {
+  currentDoc: { doc_id: string }
+}) => {
+  // store lineInfo for use on unload, when the DOM has already been unmounted
+  let lineInfo: LineInfo
+
+  const scrollHandler = throttle(
+    (event, view) => {
+      // exclude a scroll event with no target, which happens when switching docs
+      if (event.target === view.scrollDOM) {
+        lineInfo = calculateLineInfo(view)
+        dispatchScrollPosition(lineInfo, view)
+      }
+    },
+    // long enough to capture intent, but short enough that the selected heading in the outline appears current
+    120,
+    { trailing: true }
+  )
+
+  return [
+    // store/dispatch scroll position
+    ViewPlugin.define(
+      view => {
+        const unloadListener = () => {
+          if (lineInfo) {
+            storeScrollPosition(lineInfo, view, docId)
+          }
+        }
+
+        window.addEventListener('unload', unloadListener)
+
+        return {
+          update: (update: ViewUpdate) => {
+            for (const tr of update.transactions) {
+              for (const effect of tr.effects) {
+                if (effect.is(toggleVisualEffect)) {
+                  // store the scroll position when switching between source and rich text
+                  if (lineInfo) {
+                    storeScrollPosition(lineInfo, view, docId)
+                  }
+                } else if (effect.is(restoreScrollPositionEffect)) {
+                  // restore the scroll position
+                  window.setTimeout(() => {
+                    view.dispatch(scrollStoredLineToTop(tr.state.doc, docId))
+                    window.dispatchEvent(
+                      new Event('editor:scroll-position-restored')
+                    )
+                  })
+                }
+              }
+            }
+          },
+          destroy: () => {
+            scrollHandler.cancel()
+            window.removeEventListener('unload', unloadListener)
+            unloadListener()
+          },
+        }
+      },
+      {
+        eventHandlers: {
+          scroll: scrollHandler,
+        },
+      }
+    ),
+  ]
+}
+
+const restoreScrollPositionEffect = StateEffect.define()
+
+export const restoreScrollPosition = () => {
+  return {
+    effects: restoreScrollPositionEffect.of(null),
+  }
+}
+
+const calculateLineInfo = (view: EditorView) => {
+  // the top of the scrollDOM element relative to the top of the document
+  const { top, height } = view.scrollDOM.getBoundingClientRect()
+  const distanceFromDocumentTop = top - view.documentTop
+
+  return {
+    first: view.lineBlockAtHeight(distanceFromDocumentTop),
+    // top plus half the height of the scrollDOM element
+    middle: view.lineBlockAtHeight(distanceFromDocumentTop + height / 2),
+  }
+}
+
+// dispatch the middle visible line number (for the outline)
+const dispatchScrollPosition = (lineInfo: LineInfo, view: EditorView) => {
+  const middleVisibleLine = view.state.doc.lineAt(lineInfo.middle.from).number
+
+  window.dispatchEvent(
+    new CustomEvent('scroll:editor:update', {
+      detail: middleVisibleLine,
+    })
+  )
+}
+
+// store the scroll position (first visible line number, for restoring on load)
+const storeScrollPosition = (
+  lineInfo: LineInfo,
+  view: EditorView,
+  docId: string
+) => {
+  const key = buildStorageKey(docId)
+  const data = customLocalStorage.getItem(key)
+  const firstVisibleLine = view.state.doc.lineAt(lineInfo.first.from).number
+
+  customLocalStorage.setItem(key, { ...data, firstVisibleLine })
+}
+
+// restore the scroll position using the stored first visible line number
+const scrollStoredLineToTop = (doc: Text, docId: string): TransactionSpec => {
+  try {
+    const key = buildStorageKey(docId)
+    const data = customLocalStorage.getItem(key)
+
+    // restore the scroll position to its original position, or the last line of the document
+    const firstVisibleLine = Math.min(data?.firstVisibleLine ?? 1, doc.lines)
+
+    const line = doc.line(firstVisibleLine)
+
+    const selectionRange = EditorSelection.cursor(line.from)
+
+    return {
+      effects: EditorView.scrollIntoView(selectionRange, {
+        y: 'start',
+        yMargin: 0,
+      }),
+    }
+  } catch (e) {
+    // ignore invalid line number
+    console.error(e)
+    return {}
+  }
+}