Fix finding of composed text node after a mark placeholder

FIX: Fix a bug where starting a composition with stored marks or after a
noninclusive mark, with an IME that keeps the cursor at the start of the
composed text (like many Chinese IMEs) disrupted composition on Chrome.

Closes ProseMirror/prosemirror#1450
Issue ProseMirror/prosemirror#1296

src/dom.ts

@@ -63,6 +63,38 @@ export function nodeSize(node: Node) {
   return node.nodeType == 3 ? node.nodeValue!.length : node.childNodes.length
 }
 
+export function textNodeBefore(node: Node, offset: number) {
+  for (;;) {
+    if (node.nodeType == 3 && offset) return node as Text
+    if (node.nodeType == 1 && offset > 0) {
+      if ((node as HTMLElement).contentEditable != "false") return null
+      node = node.childNodes[offset - 1]
+      offset = nodeSize(node)
+    } else if (node.parentNode && !hasBlockDesc(node)) {
+      offset = domIndex(node)
+      node = node.parentNode
+    } else {
+      return null
+    }
+  }
+}
+
+export function textNodeAfter(node: Node, offset: number) {
+  for (;;) {
+    if (node.nodeType == 3 && offset < node.nodeValue!.length) return node as Text
+    if (node.nodeType == 1 && offset < node.childNodes.length) {
+      if ((node as HTMLElement).contentEditable != "false") return null
+      node = node.childNodes[offset]
+      offset = 0
+    } else if (node.parentNode && !hasBlockDesc(node)) {
+      offset = domIndex(node) + 1
+      node = node.parentNode
+    } else {
+      return null
+    }
+  }
+}
+
 export function isOnEdge(node: Node, offset: number, parent: Node) {
   for (let atStart = offset == 0, atEnd = offset == nodeSize(node); atStart || atEnd;) {
     if (node == parent) return true

src/domchange.ts

@@ -143,13 +143,6 @@ export function readDOMChange(view: EditorView, from: number, to: number, typeOv
       return
     }
   }
-  // Chrome sometimes leaves the cursor before the inserted text when
-  // composing after a cursor wrapper. This moves it forward.
-  if (browser.chrome && view.cursorWrapper && parse.sel && parse.sel.anchor == view.cursorWrapper.deco.from &&
-      parse.sel.head == parse.sel.anchor) {
-    let size = change.endB - change.start
-    parse.sel = {anchor: parse.sel.anchor + size, head: parse.sel.anchor + size}
-  }
 
   view.input.domChangeCount++
   // Handle the case where overwriting a selection by typing matches

src/viewdesc.ts

@@ -1,7 +1,7 @@
 import {DOMSerializer, Fragment, Mark, Node, ParseRule} from "prosemirror-model"
 import {TextSelection} from "prosemirror-state"
 
-import {domIndex, isEquivalentPosition, nodeSize, DOMNode} from "./dom"
+import {domIndex, isEquivalentPosition, DOMNode, textNodeBefore, textNodeAfter} from "./dom"
 import * as browser from "./browser"
 import {Decoration, DecorationSource, WidgetConstructor, WidgetType, NodeType} from "./decoration"
 import {EditorView} from "./index"
@@ -760,7 +760,14 @@ export class NodeViewDesc extends ViewDesc {
     let {from, to} = view.state.selection
     if (!(view.state.selection instanceof TextSelection) || from < pos || to > pos + this.node.content.size) return null
     let sel = view.domSelectionRange()
-    let textNode = nearbyTextNode(sel.focusNode!, sel.focusOffset)
+    let textBefore = textNodeBefore(sel.focusNode!, sel.focusOffset)
+    let textAfter = textNodeAfter(sel.focusNode!, sel.focusOffset)
+    let textNode = textBefore || textAfter
+    if (textBefore && textAfter && textBefore != textAfter) {
+      let descAfter = textAfter.pmViewDesc
+      if (!descAfter || descAfter instanceof TextViewDesc && descAfter.node.text != textAfter.nodeValue)
+        textNode = textAfter
+    }
     if (!textNode || !this.dom.contains(textNode.parentNode)) return null
 
     if (this.node.inlineContent) {
@@ -1470,23 +1477,6 @@ function iosHacks(dom: HTMLElement) {
   }
 }
 
-function nearbyTextNode(node: DOMNode, offset: number): Text | null {
-  for (;;) {
-    if (node.nodeType == 3) return node as Text
-    if (node.nodeType == 1 && offset > 0) {
-      if (node.childNodes.length > offset && node.childNodes[offset].nodeType == 3)
-        return node.childNodes[offset] as Text
-      node = node.childNodes[offset - 1]
-      offset = nodeSize(node)
-    } else if (node.nodeType == 1 && offset < node.childNodes.length) {
-      node = node.childNodes[offset]
-      offset = 0
-    } else {
-      return null
-    }
-  }
-}
-
 // Find a piece of text in an inline fragment, overlapping from-to
 function findTextInFragment(frag: Fragment, text: string, from: number, to: number) {
   for (let i = 0, pos = 0; i < frag.childCount && pos <= to;) {