pdf.js/src/core/xfa/bind.js

/* Copyright 2021 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import {
  $appendChild,
  $clone,
  $consumed,
  $content,
  $data,
  $finalize,
  $getAttributeIt,
  $getChildren,
  $getDataValue,
  $getParent,
  $getRealChildrenByNameIt,
  $global,
  $hasSettableValue,
  $indexOf,
  $insertAt,
  $isBindable,
  $isDataValue,
  $isDescendent,
  $namespaceId,
  $nodeName,
  $removeChild,
  $setValue,
  $text,
  XFAAttribute,
  XmlObject,
} from "./xfa_object.js";
import { BindItems, Field, Items, SetProperty, Text } from "./template.js";
import { createDataNode, searchNode } from "./som.js";
import { NamespaceIds } from "./namespaces.js";
import { warn } from "../../shared/util.js";

function createText(content) {
  const node = new Text({});
  node[$content] = content;
  return node;
}

class Binder {
  constructor(root) {
    this.root = root;
    this.datasets = root.datasets;
    if (root.datasets && root.datasets.data) {
      this.data = root.datasets.data;
    } else {
      this.data = new XmlObject(NamespaceIds.datasets.id, "data");
    }
    this.emptyMerge = this.data[$getChildren]().length === 0;

    this.root.form = this.form = root.template[$clone]();
  }

  _isConsumeData() {
    return !this.emptyMerge && this._mergeMode;
  }

  _isMatchTemplate() {
    return !this._isConsumeData();
  }

  bind() {
    this._bindElement(this.form, this.data);
    return this.form;
  }

  getData() {
    return this.data;
  }

  _bindValue(formNode, data, picture) {
    // Nodes must have the same "type": container or value.
    // Here we make the link between form node and
    // data node (through $data property): we'll use it
    // to save form data.

    formNode[$data] = data;
    if (formNode[$hasSettableValue]()) {
      if (data[$isDataValue]()) {
        const value = data[$getDataValue]();
        // TODO: use picture.
        formNode[$setValue](createText(value));
      } else if (
        formNode instanceof Field &&
        formNode.ui &&
        formNode.ui.choiceList &&
        formNode.ui.choiceList.open === "multiSelect"
      ) {
        const value = data[$getChildren]()
          .map(child => child[$content].trim())
          .join("\n");
        formNode[$setValue](createText(value));
      } else if (this._isConsumeData()) {
        warn(`XFA - Nodes haven't the same type.`);
      }
    } else if (!data[$isDataValue]() || this._isMatchTemplate()) {
      this._bindElement(formNode, data);
    } else {
      warn(`XFA - Nodes haven't the same type.`);
    }
  }

  _findDataByNameToConsume(name, isValue, dataNode, global) {
    if (!name) {
      return null;
    }

    // Firstly, we try to find a node with the given name:
    //  - in dataNode;
    //  - if not found, then in parent;
    //  - and if not in found, then in grand-parent.
    let generator, match;
    for (let i = 0; i < 3; i++) {
      generator = dataNode[$getRealChildrenByNameIt](
        name,
        /* allTransparent = */ false,
        /* skipConsumed = */ true
      );
      // Try to find a match of the same kind.
      while (true) {
        match = generator.next().value;
        if (!match) {
          break;
        }

        if (isValue === match[$isDataValue]()) {
          return match;
        }
      }
      if (
        dataNode[$namespaceId] === NamespaceIds.datasets.id &&
        dataNode[$nodeName] === "data"
      ) {
        break;
      }
      dataNode = dataNode[$getParent]();
    }

    if (!global) {
      return null;
    }

    // Secondly, if global try to find it just under the root of datasets
    // (which is the location of global variables).
    generator = this.data[$getRealChildrenByNameIt](
      name,
      /* allTransparent = */ false,
      /* skipConsumed = */ false
    );

    while (true) {
      match = generator.next().value;
      if (!match) {
        break;
      }

      if (match[$global]) {
        return match;
      }
    }

    // Thirdly, try to find it in attributes.
    generator = this.data[$getAttributeIt](name, /* skipConsumed = */ true);
    match = generator.next().value;
    if (match && match[$isDataValue]()) {
      return match;
    }

    return null;
  }

  _setProperties(formNode, dataNode) {
    // For example:
    // <field name="LastName" ...>
    //   <setProperty ref="$data.Main.Style.NameFont" target="font.typeface"/>
    //   <setProperty ref="$data.Main.Style.NameSize" target="font.size"/>
    //   <setProperty ref="$data.Main.Help.LastName" target="assist.toolTip"/>
    // </field>

    if (!formNode.hasOwnProperty("setProperty")) {
      return;
    }

    for (const { ref, target, connection } of formNode.setProperty.children) {
      if (connection) {
        // TODO: evaluate if we should implement this feature.
        // Skip for security reasons.
        continue;
      }
      if (!ref) {
        continue;
      }

      const [node] = searchNode(
        this.root,
        dataNode,
        ref,
        false /* = dotDotAllowed */,
        false /* = useCache */
      );
      if (!node) {
        warn(`XFA - Invalid reference: ${ref}.`);
        continue;
      }

      if (!node[$isDescendent](this.data)) {
        warn(`XFA - Invalid node: must be a data node.`);
        continue;
      }

      const [targetNode] = searchNode(
        this.root,
        formNode,
        target,
        false /* = dotDotAllowed */,
        false /* = useCache */
      );
      if (!targetNode) {
        warn(`XFA - Invalid target: ${target}.`);
        continue;
      }

      if (!targetNode[$isDescendent](formNode)) {
        warn(`XFA - Invalid target: must be a property or subproperty.`);
        continue;
      }

      const targetParent = targetNode[$getParent]();
      if (
        targetNode instanceof SetProperty ||
        targetParent instanceof SetProperty
      ) {
        warn(
          `XFA - Invalid target: cannot be a setProperty or one of its properties.`
        );
        continue;
      }

      if (
        targetNode instanceof BindItems ||
        targetParent instanceof BindItems
      ) {
        warn(
          `XFA - Invalid target: cannot be a bindItems or one of its properties.`
        );
        continue;
      }

      const content = node[$text]();
      const name = targetNode[$nodeName];

      if (targetNode instanceof XFAAttribute) {
        const attrs = Object.create(null);
        attrs[name] = content;
        const obj = Reflect.construct(
          Object.getPrototypeOf(targetParent).constructor,
          [attrs]
        );
        targetParent[name] = obj[name];
        continue;
      }

      if (!targetNode.hasOwnProperty($content)) {
        warn(`XFA - Invalid node to use in setProperty`);
        continue;
      }

      targetNode[$data] = node;
      targetNode[$content] = content;
      targetNode[$finalize]();
    }
  }

  _bindItems(formNode, dataNode) {
    // For example:
    // <field name="CardName"...>
    //   <bindItems ref="$data.main.ccs.cc[*]" labelRef="uiname"
    //              valueRef="token"/>
    //   <ui><choiceList/></ui>
    // </field>

    if (
      !formNode.hasOwnProperty("items") ||
      !formNode.hasOwnProperty("bindItems") ||
      formNode.bindItems.isEmpty()
    ) {
      return;
    }

    for (const item of formNode.items.children) {
      formNode[$removeChild](item);
    }

    formNode.items.clear();

    const labels = new Items({});
    const values = new Items({});

    formNode[$appendChild](labels);
    formNode.items.push(labels);

    formNode[$appendChild](values);
    formNode.items.push(values);

    for (const { ref, labelRef, valueRef, connection } of formNode.bindItems
      .children) {
      if (connection) {
        // TODO: evaluate if we should implement this feature.
        // Skip for security reasons.
        continue;
      }
      if (!ref) {
        continue;
      }

      const nodes = searchNode(
        this.root,
        dataNode,
        ref,
        false /* = dotDotAllowed */,
        false /* = useCache */
      );
      if (!nodes) {
        warn(`XFA - Invalid reference: ${ref}.`);
        continue;
      }
      for (const node of nodes) {
        if (!node[$isDescendent](this.datasets)) {
          warn(`XFA - Invalid ref (${ref}): must be a datasets child.`);
          continue;
        }

        const [labelNode] = searchNode(
          this.root,
          node,
          labelRef,
          true /* = dotDotAllowed */,
          false /* = useCache */
        );
        if (!labelNode) {
          warn(`XFA - Invalid label: ${labelRef}.`);
          continue;
        }

        if (!labelNode[$isDescendent](this.datasets)) {
          warn(`XFA - Invalid label: must be a datasets child.`);
          continue;
        }

        const [valueNode] = searchNode(
          this.root,
          node,
          valueRef,
          true /* = dotDotAllowed */,
          false /* = useCache */
        );
        if (!valueNode) {
          warn(`XFA - Invalid value: ${valueRef}.`);
          continue;
        }

        if (!valueNode[$isDescendent](this.datasets)) {
          warn(`XFA - Invalid value: must be a datasets child.`);
          continue;
        }

        const label = createText(labelNode[$text]());
        const value = createText(valueNode[$text]());

        labels[$appendChild](label);
        labels.text.push(label);

        values[$appendChild](value);
        values.text.push(value);
      }
    }
  }

  _bindOccurrences(formNode, matches, picture) {
    // Insert nodes which are not in the template but reflect
    // what we've in data tree.

    let baseClone;
    if (matches.length > 1) {
      // Clone before binding to avoid bad state.
      baseClone = formNode[$clone]();
    }

    this._bindValue(formNode, matches[0], picture);
    this._setProperties(formNode, matches[0]);
    this._bindItems(formNode, matches[0]);

    if (matches.length === 1) {
      return;
    }

    const parent = formNode[$getParent]();
    const name = formNode[$nodeName];
    const pos = parent[$indexOf](formNode);

    for (let i = 1, ii = matches.length; i < ii; i++) {
      const match = matches[i];
      const clone = baseClone[$clone]();
      clone.occur.min = 1;
      clone.occur.max = 1;
      clone.occur.initial = 1;
      parent[name].push(clone);
      parent[$insertAt](pos + i, clone);

      this._bindValue(clone, match, picture);
      this._setProperties(clone, match);
      this._bindItems(clone, match);
    }
  }

  _createOccurrences(formNode) {
    if (!this.emptyMerge) {
      return;
    }

    const { occur } = formNode;
    if (!occur || occur.initial <= 1) {
      return;
    }

    const parent = formNode[$getParent]();
    const name = formNode[$nodeName];

    for (let i = 0, ii = occur.initial; i < ii; i++) {
      const clone = formNode[$clone]();
      clone.occur.min = 1;
      clone.occur.max = 1;
      clone.occur.initial = 1;
      parent[name].push(clone);
      parent[$appendChild](clone);
    }
  }

  _getOccurInfo(formNode) {
    const { occur } = formNode;
    const dataName = formNode.name;
    if (!occur || !dataName) {
      return [1, 1];
    }
    const max = occur.max === -1 ? Infinity : occur.max;
    return [occur.min, max];
  }

  _bindElement(formNode, dataNode) {
    // Some nodes can be useless because min=0 so remove them
    // after the loop to avoid bad things.

    const uselessNodes = [];

    this._createOccurrences(formNode);

    for (const child of formNode[$getChildren]()) {
      if (child[$data]) {
        // Already bound.
        continue;
      }

      if (this._mergeMode === undefined && child[$nodeName] === "subform") {
        this._mergeMode = child.mergeMode === "consumeData";

        // XFA specs p. 182:
        // The highest-level subform and the data node representing
        // the current record are special; they are always
        // bound even if their names don't match.
        const dataChildren = dataNode[$getChildren]();
        if (dataChildren.length > 0) {
          this._bindOccurrences(child, [dataChildren[0]], null);
        } else if (this.emptyMerge) {
          const dataChild = new XmlObject(
            dataNode[$namespaceId],
            child.name || "root"
          );
          dataNode[$appendChild](dataChild);
          this._bindElement(child, dataChild);
        }
        continue;
      }

      if (!child[$isBindable]()) {
        // The node cannot contain some new data so there is nothing
        // to create in the data node.
        continue;
      }

      let global = false;
      let picture = null;
      let ref = null;
      let match = null;
      if (child.bind) {
        switch (child.bind.match) {
          case "none":
            this._bindElement(child, dataNode);
            continue;
          case "global":
            global = true;
            break;
          case "dataRef":
            if (!child.bind.ref) {
              warn(`XFA - ref is empty in node ${child[$nodeName]}.`);
              this._bindElement(child, dataNode);
              continue;
            }
            ref = child.bind.ref;
            break;
          default:
            break;
        }
        if (child.bind.picture) {
          picture = child.bind.picture[$content];
        }
      }

      const [min, max] = this._getOccurInfo(child);

      if (ref) {
        // Don't use a cache for searching: nodes can change during binding.
        match = searchNode(
          this.root,
          dataNode,
          ref,
          true /* = dotDotAllowed */,
          false /* = useCache */
        );
        if (match === null) {
          // Nothing found: we must create some nodes in data in order
          // 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 (this._isConsumeData()) {
            match[$consumed] = true;
          }

          // Don't bind the value in newly created node because it's empty.
          this._bindElement(child, match);
          continue;
        } else {
          if (this._isConsumeData()) {
            // Filter out consumed nodes.
            match = match.filter(node => !node[$consumed]);
          }
          if (match.length > max) {
            match = match.slice(0, max);
          } else if (match.length === 0) {
            match = null;
          }
          if (match && this._isConsumeData()) {
            match.forEach(node => {
              node[$consumed] = true;
            });
          }
        }
      } else {
        if (!child.name) {
          this._bindElement(child, dataNode);
          continue;
        }
        if (this._isConsumeData()) {
          // In consumeData mode, search for the next node with the given name.
          // occurs.max gives us the max number of node to match.
          const matches = [];
          while (matches.length < max) {
            const found = this._findDataByNameToConsume(
              child.name,
              child[$hasSettableValue](),
              dataNode,
              global
            );
            if (!found) {
              break;
            }
            found[$consumed] = true;
            matches.push(found);
          }
          match = matches.length > 0 ? matches : null;
        } else {
          // If we've an empty merge, there are no reason
          // to make multiple bind so skip consumed nodes.
          match = dataNode[$getRealChildrenByNameIt](
            child.name,
            /* allTransparent = */ false,
            /* skipConsumed = */ this.emptyMerge
          ).next().value;
          if (!match) {
            // We're in matchTemplate mode so create a node in data to reflect
            // what we've in template.
            match = new XmlObject(dataNode[$namespaceId], child.name);
            if (this.emptyMerge) {
              match[$consumed] = true;
            }
            dataNode[$appendChild](match);

            // Don't bind the value in newly created node because it's empty.
            this._bindElement(child, match);
            continue;
          }
          if (this.emptyMerge) {
            match[$consumed] = true;
          }
          match = [match];
        }
      }

      if (match) {
        if (match.length < min) {
          warn(
            `XFA - Must have at least ${min} occurrences: ${formNode[$nodeName]}.`
          );
          continue;
        }
        this._bindOccurrences(child, match, picture);
      } else if (min > 0) {
        this._setProperties(child, dataNode);
        this._bindItems(child, dataNode);
        this._bindElement(child, dataNode);
      } else {
        uselessNodes.push(child);
      }
    }

    uselessNodes.forEach(node => node[$getParent]()[$removeChild](node));
  }
}

export { Binder };