XFA - Don't fail xfa loading because of a JS subexpression in SOM expressions

- Fix for one pdf in bug 1717668 (PDFIUM-292-0.pdf).

src/core/xfa/bind.js

@@ -545,6 +545,12 @@ class Binder {
           // to have something to match with the given expression.
           // See http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.364.2157&rep=rep1&type=pdf#page=199
           match = createDataNode(this.data, dataNode, ref);
+          if (!match) {
+            // For example if the node contains a .(...) then it isn't
+            // findable.
+            // TODO: remove this when .(...) is implemented.
+            continue;
+          }
           if (this._isConsumeData()) {
             match[$consumed] = true;
           }

src/core/xfa/som.js

@@ -60,7 +60,10 @@ function parseIndex(index) {
   return parseInt(index, 10) || 0;
 }
 
-function parseExpression(expr, dotDotAllowed) {
+// For now expressions containaing .[...] or .(...) are not
+// evaluated so don't parse them.
+// TODO: implement that stuff and the remove the noExpr param.
+function parseExpression(expr, dotDotAllowed, noExpr = true) {
   let match = expr.match(namePattern);
   if (!match) {
     return null;
@@ -108,10 +111,22 @@ function parseExpression(expr, dotDotAllowed) {
         operator = operators.dotHash;
         break;
       case "[":
+        if (noExpr) {
+          warn(
+            "XFA - SOM expression contains a FormCalc subexpression which is not supported for now."
+          );
+          return null;
+        }
         // TODO: FormCalc expression so need to use the parser
         operator = operators.dotBracket;
         break;
       case "(":
+        if (noExpr) {
+          warn(
+            "XFA - SOM expression contains a JavaScript subexpression which is not supported for now."
+          );
+          return null;
+        }
         // TODO:
         // Javascript expression: should be a boolean operation with a path
         // so maybe we can have our own parser for that stuff or

src/core/xfa/template.js

@@ -172,6 +172,9 @@ function handleBreak(node) {
   let target = null;
   if (node.target) {
     target = root[$searchNode](node.target, node[$getParent]());
+    if (!target) {
+      return false;
+    }
     target = target ? target[0] : target;
   }
 
@@ -197,12 +200,12 @@ function handleBreak(node) {
     target = null;
   }
 
-  const pageArea = target[$getParent]();
-  const contentAreas = pageArea.contentArea.children;
+  const pageArea = target && target[$getParent]();
 
   let index;
   if (node.startNew) {
     if (target) {
+      const contentAreas = pageArea.contentArea.children;
       index = contentAreas.findIndex(e => e === target) - 1;
     } else {
       index = currentPageArea.contentArea.children.findIndex(
@@ -210,6 +213,7 @@ function handleBreak(node) {
       );
     }
   } else if (target && target !== currentContentArea) {
+    const contentAreas = pageArea.contentArea.children;
     index = contentAreas.findIndex(e => e === target) - 1;
   } else {
     return false;