fix: bound retained rich text content

src/onenote/one/content.ts

@@ -54,6 +54,7 @@ import {
 export interface OneNoteContentBudget {
   blocks: number;
   textRuns: number;
+  textCharacters: number;
   tableCells: number;
   inkPoints: number;
 }
@@ -72,7 +73,13 @@ interface ContentContext extends OneNoteContentParseOptions {
 }
 
 export function createContentBudget(): OneNoteContentBudget {
-  return { blocks: 0, textRuns: 0, tableCells: 0, inkPoints: 0 };
+  return {
+    blocks: 0,
+    textRuns: 0,
+    textCharacters: 0,
+    tableCells: 0,
+    inkPoints: 0,
+  };
 }
 
 /** Parse page graph roots into an inert, recursively structured content tree. */
@@ -235,6 +242,7 @@ function parseRichText(
   let sourceText = optionalString(object, PROPERTY.RichEditTextUnicode);
   sourceText ??= optionalLatin1(object, PROPERTY.TextExtendedAscii);
   sourceText = (sourceText ?? '').split('\0').join('');
+  incrementTextCharacterBudget(context, sourceText.length);
 
   const paragraphStyleId = objectReferences(object, PROPERTY.ParagraphStyle)[0];
   const paragraphStyle = paragraphStyleId
@@ -1223,6 +1231,22 @@ function incrementTextRunBudget(context: ContentContext, amount: number): void {
   }
 }
 
+function incrementTextCharacterBudget(
+  context: ContentContext,
+  amount: number
+): void {
+  const next = context.budget.textCharacters + amount;
+  if (
+    !Number.isSafeInteger(next) ||
+    next > context.limits.maxExtractedTextChars
+  ) {
+    throw new Error(
+      `Rich-text character count exceeds ${context.limits.maxExtractedTextChars}`
+    );
+  }
+  context.budget.textCharacters = next;
+}
+
 function incrementTableCellBudget(context: ContentContext): void {
   context.budget.tableCells += 1;
   if (context.budget.tableCells > context.limits.maxTableCells) {