XFA - Fix lot of layout issues

- I thought it was possible to rely on browser layout engine to handle layout stuff but it isn't possible
    - mainly because when a contentArea overflows, we must continue to layout in the next contentArea
    - when no more contentArea is available then we must go to the next page...
    - we must handle breakBefore and breakAfter which allows to "break" the layout to go to the next container
  - Sometimes some containers don't provide their dimensions so we must compute them in order to know where to put
    them in their parents but to compute those dimensions we need to layout the container itself...
  - See top of file layout.js for more explanations about layout.
  - fix few bugs in other places I met during my work on layout.

src/core/xfa/xfa_object.js

@@ -13,14 +13,16 @@
  * limitations under the License.
  */
 
-import { getInteger, getKeyword } from "./utils.js";
+import { getInteger, getKeyword, HTMLResult } from "./utils.js";
 import { shadow, warn } from "../../shared/util.js";
 import { NamespaceIds } from "./namespaces.js";
 
 // We use these symbols to avoid name conflict between tags
 // and properties/methods names.
 const $acceptWhitespace = Symbol();
+const $addHTML = Symbol();
 const $appendChild = Symbol();
+const $break = Symbol();
 const $childrenToHTML = Symbol();
 const $clean = Symbol();
 const $cleanup = Symbol();
@@ -31,16 +33,21 @@ const $data = Symbol("data");
 const $dump = Symbol();
 const $extra = Symbol("extra");
 const $finalize = Symbol();
+const $flushHTML = Symbol();
 const $getAttributeIt = Symbol();
+const $getAvailableSpace = Symbol();
 const $getChildrenByClass = Symbol();
 const $getChildrenByName = Symbol();
 const $getChildrenByNameIt = Symbol();
+const $getDataValue = Symbol();
 const $getRealChildrenByNameIt = Symbol();
 const $getChildren = Symbol();
+const $getNextPage = Symbol();
 const $getParent = Symbol();
 const $global = Symbol();
 const $hasItem = Symbol();
 const $hasSettableValue = Symbol();
+const $ids = Symbol();
 const $indexOf = Symbol();
 const $insertAt = Symbol();
 const $isDataValue = Symbol();
@@ -55,6 +62,7 @@ const $onChildCheck = Symbol();
 const $onText = Symbol();
 const $removeChild = Symbol();
 const $resolvePrototypes = Symbol();
+const $searchNode = Symbol();
 const $setId = Symbol();
 const $setSetAttributes = Symbol();
 const $setValue = Symbol();
@@ -70,6 +78,7 @@ const _children = Symbol("_children");
 const _cloneAttribute = Symbol();
 const _dataValue = Symbol();
 const _defaultValue = Symbol();
+const _filteredChildrenGenerator = Symbol();
 const _getPrototype = Symbol();
 const _getUnsetAttributes = Symbol();
 const _hasChildren = Symbol();
@@ -270,20 +279,67 @@ class XFAObject {
   }
 
   [$toHTML]() {
+    return HTMLResult.EMPTY;
+  }
+
+  *[_filteredChildrenGenerator](filter, include) {
+    for (const node of this[$getChildren]()) {
+      if (!filter || include === filter.has(node[$nodeName])) {
+        const availableSpace = this[$getAvailableSpace]();
+        const res = node[$toHTML](availableSpace);
+        if (!res.success) {
+          this[$extra].failingNode = node;
+        }
+        yield res;
+      }
+    }
+  }
+
+  [$flushHTML]() {
     return null;
   }
 
+  [$addHTML](html, bbox) {
+    this[$extra].children.push(html);
+  }
+
+  [$getAvailableSpace]() {}
+
   [$childrenToHTML]({ filter = null, include = true }) {
-    const res = [];
-    this[$getChildren]().forEach(node => {
-      if (!filter || include === filter.has(node[$nodeName])) {
-        const html = node[$toHTML]();
-        if (html) {
-          res.push(html);
-        }
+    if (!this[$extra].generator) {
+      this[$extra].generator = this[_filteredChildrenGenerator](
+        filter,
+        include
+      );
+    } else {
+      const availableSpace = this[$getAvailableSpace]();
+      const res = this[$extra].failingNode[$toHTML](availableSpace);
+      if (!res.success) {
+        return false;
       }
-    });
-    return res;
+      if (res.html) {
+        this[$addHTML](res.html, res.bbox);
+      }
+      delete this[$extra].failingNode;
+    }
+
+    while (true) {
+      const gen = this[$extra].generator.next();
+      if (gen.done) {
+        break;
+      }
+      const res = gen.value;
+      if (!res.success) {
+        return false;
+      }
+      if (res.html) {
+        this[$addHTML](res.html, res.bbox);
+      }
+    }
+
+    this[$extra].generator = null;
+
+    return true;
   }
 
   [$setSetAttributes](attributes) {
@@ -640,13 +696,13 @@ class XmlObject extends XFAObject {
 
   [$toHTML]() {
     if (this[$nodeName] === "#text") {
-      return {
+      return HTMLResult.success({
         name: "#text",
         value: this[$content],
-      };
+      });
     }
 
-    return null;
+    return HTMLResult.EMPTY;
   }
 
   [$getChildren](name = null) {
@@ -710,11 +766,27 @@ class XmlObject extends XFAObject {
 
   [$isDataValue]() {
     if (this[_dataValue] === null) {
-      return this[_children].length === 0;
+      return (
+        this[_children].length === 0 ||
+        this[_children][0][$namespaceId] === NamespaceIds.xhtml.id
+      );
     }
     return this[_dataValue];
   }
 
+  [$getDataValue]() {
+    if (this[_dataValue] === null) {
+      if (this[_children].length === 0) {
+        return this[$content].trim();
+      }
+      if (this[_children][0][$namespaceId] === NamespaceIds.xhtml.id) {
+        return this[_children][0][$text]().trim();
+      }
+      return null;
+    }
+    return this[$content].trim();
+  }
+
   [$dump]() {
     const dumped = Object.create(null);
     if (this[$content]) {
@@ -811,7 +883,9 @@ class Option10 extends IntegerObject {
 
 export {
   $acceptWhitespace,
+  $addHTML,
   $appendChild,
+  $break,
   $childrenToHTML,
   $clean,
   $cleanup,
@@ -822,16 +896,21 @@ export {
   $dump,
   $extra,
   $finalize,
+  $flushHTML,
   $getAttributeIt,
+  $getAvailableSpace,
   $getChildren,
   $getChildrenByClass,
   $getChildrenByName,
   $getChildrenByNameIt,
+  $getDataValue,
+  $getNextPage,
   $getParent,
   $getRealChildrenByNameIt,
   $global,
   $hasItem,
   $hasSettableValue,
+  $ids,
   $indexOf,
   $insertAt,
   $isDataValue,
@@ -845,6 +924,7 @@ export {
   $onText,
   $removeChild,
   $resolvePrototypes,
+  $searchNode,
   $setId,
   $setSetAttributes,
   $setValue,