#364 Treat footnotes inside footnotes gracefully.

By processing them as non-footnote content.

openhtmltopdf-core/src/main/java/com/openhtmltopdf/layout/BoxBuilder.java

@@ -28,6 +28,7 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.logging.Level;
 
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
@@ -67,6 +68,8 @@
 import com.openhtmltopdf.render.FlowingColumnContainerBox;
 import com.openhtmltopdf.render.InlineBox;
 import com.openhtmltopdf.util.OpenUtil;
+import com.openhtmltopdf.util.XRLog;
+import com.openhtmltopdf.util.LogMessageId;
 
 /**
  * This class is responsible for creating the box tree from the DOM. This is
@@ -1286,8 +1289,7 @@ private static void createElementChild(
  Node working,
  List<Styleable> children,
  ChildBoxInfo info,
- CreateChildrenContext context,
- boolean allowFootnotes) {
+ CreateChildrenContext context) {
 
  Styleable child = null;
  SharedContext sharedContext = c.getSharedContext();
@@ -1321,7 +1323,7 @@ private static void createElementChild(
  return;
  }
 
- if (style.isFootnote() && allowFootnotes) {
+ if (style.isFootnote() && !c.isInFloatBottom()) {
  c.setFootnoteIndex(c.getFootnoteIndex() + 1);
 
  // This is the official footnote call content that can generate zero or more boxes
@@ -1462,11 +1464,14 @@ private static BlockBox createFootnoteBody(
  footnoteBody.setContainingLayer(layer);
 
  c.pushLayer(layer);
+ c.setIsInFloatBottom(true);
 
  CreateChildrenContext context = new CreateChildrenContext(false, false, style.getParent(), false);
- createElementChild(c, (Element) element.getParentNode(), footnoteBody, element, footnoteChildren, footnoteChildInfo, context, false);
+ createElementChild(c, (Element) element.getParentNode(), footnoteBody, element, footnoteChildren, footnoteChildInfo, context);
  resolveChildren(c, footnoteBody, footnoteChildren, footnoteChildInfo);
 
+ c.setFootnoteAllowed(true);
+ c.setIsInFloatBottom(false);
  c.popLayer();
 
 // System.out.println();
@@ -1518,7 +1523,13 @@ private static void createChildren(
  insertGeneratedContent(c, parent, parentStyle, "before", children, info);
 
  if (parentStyle.isFootnote()) {
- insertGeneratedContent(c, parent, parentStyle, "footnote-marker", children, info);
+ if (c.isFootnoteAllowed()) {
+ insertGeneratedContent(c, parent, parentStyle, "footnote-marker", children, info);
+ // Ban further footnote content until we bubble back up to createFootnoteBody.
+ c.setFootnoteAllowed(false);
+ } else {
+ XRLog.log(Level.WARNING, LogMessageId.LogMessageId0Param.GENERAL_NO_FOOTNOTES_INSIDE_FOOTNOTES);
+ }
  }
 
  Node working = parent.getFirstChild();
@@ -1532,7 +1543,7 @@ private static void createChildren(
 
  if (nodeType == Node.ELEMENT_NODE) {
  createElementChild(
- c, parent, blockParent, working, children, info, context, true);
+ c, parent, blockParent, working, children, info, context);
  } else if (nodeType == Node.TEXT_NODE || nodeType == Node.CDATA_SECTION_NODE) {
  context.needStartText = false;
  context.needEndText = false;

openhtmltopdf-core/src/main/java/com/openhtmltopdf/layout/LayoutContext.java

@@ -106,6 +106,7 @@ public enum BlockBoxingState {
 
  private int _footnoteIndex;
  private FootnoteManager _footnoteManager;
+ private boolean _isFootnoteAllowed = true;
 
  @Override
  public TextRenderer getTextRenderer() {
@@ -541,6 +542,21 @@ public void setBreakAtLineContext(BreakAtLineContext breakAtLineContext) {
  _breakAtLineContext = breakAtLineContext;
  }
 
+ /**
+ * Whether further footnote content is allowed. Used to prohibit
+ * footnotes inside footnotes.
+ */
+ public boolean isFootnoteAllowed() {
+ return _isFootnoteAllowed;
+ }
+
+ /**
+ * See {@link #isFootnoteAllowed()}.
+ */
+ public void setFootnoteAllowed(boolean allowed) {
+ this._isFootnoteAllowed = allowed;
+ }
+
  /**
  * See {@link #isInFloatBottom()}
  */

openhtmltopdf-core/src/main/java/com/openhtmltopdf/util/LogMessageId.java

@@ -36,6 +36,7 @@ enum LogMessageId0Param implements LogMessageId {
 
  MATCH_TRYING_TO_SET_MORE_THAN_ONE_PSEUDO_ELEMENT(XRLog.MATCH, "Trying to set more than one pseudo-element"),
 
+ GENERAL_NO_FOOTNOTES_INSIDE_FOOTNOTES(XRLog.GENERAL, "Footnotes inside footnotes are not supported"),
  GENERAL_IMPORT_FONT_FACE_RULES_HAS_NOT_BEEN_CALLED(XRLog.GENERAL, "importFontFaceRules has not been called for this pdf transcoder"),
  GENERAL_PDF_ACCESSIBILITY_NO_ALT_ATTRIBUTE_PROVIDED_FOR_IMAGE(XRLog.GENERAL, "No alt attribute provided for image/replaced in PDF/UA document."),
  GENERAL_PDF_SPECIFIED_FONTS_DONT_CONTAIN_A_SPACE_CHARACTER(XRLog.GENERAL, "Specified fonts don't contain a space character!"),
@@ -56,6 +57,7 @@ enum LogMessageId0Param implements LogMessageId {
  EXCEPTION_COULD_NOT_READ_PDF_AS_SRC_FOR_IMG(XRLog.EXCEPTION, "Could not read pdf passed as src for img element!"),
  EXCEPTION_COULD_NOT_PARSE_DEFAULT_STYLESHEET(XRLog.EXCEPTION, "Could not parse default stylesheet"),
  EXCEPTION_SELECTOR_BAD_SIBLING_AXIS(XRLog.EXCEPTION, "Bad sibling axis");
+
 
  private final String where;
  private final String messageFormat;

openhtmltopdf-examples/src/main/resources/visualtest/html/footnote/issue-364-footnote-inside-footnote.html

@@ -0,0 +1,53 @@
+<html>
+<head>
+<style>
+@page {
+ size: 300px 300px;
+}
+html {
+ orphans: 0;
+ widows: 0;
+}
+body {
+ font-size: 20px;
+}
+.footnote {
+ color: green;
+ float: footnote;
+}
+::footnote-call {
+ counter-increment: footnote;
+ content: " [fn " counter(footnote) "] ";
+}
+::footnote-marker {
+ content: "fn. " counter(footnote);
+}
+</style>
+</head>
+<body>
+ This is some in-flow content.
+
+ <div class="footnote">
+ This is a footnote with a footnote inside.
+ <div class="footnote">
+ This is the inner footnote.
+ </div>
+ And another:
+ <div class="footnote">
+ Another fn inside fn.
+ <div class="footnote">
+ Grandchild footnote in footnote.
+ </div>
+ </div>
+ </div>
+
+ Even more in-flow content.
+
+ <div class="footnote">
+ Second footnote.
+ </div>
+
+ End of document.
+
+</body>
+</html>

openhtmltopdf-examples/src/test/java/com/openhtmltopdf/visualregressiontests/FootnoteVisualRegressionTest.java

@@ -165,4 +165,13 @@ public void testIssue364NonPaginatedTable() throws IOException {
  assertTrue(vt.runTest("issue-364-non-paginated-table"));
  }
 
+ /**
+ * Tests that footnotes inside footnotes are treated as non-footnote content
+ * and do not cause infinite loop, stack overflow, OOM, etc.
+ */
+ @Test
+ public void testIssue364FootnoteInsideFootnote() throws IOException {
+ assertTrue(vt.runTest("issue-364-footnote-inside-footnote"));
+ }
+
 }