gerrit/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html

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Copyright (C) 2016 The Android Open Source Project

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

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distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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-->
<link rel="import" href="../../../bower_components/polymer/polymer.html">
<link rel="import" href="../../core/gr-reporting/gr-reporting.html">
<link rel="import" href="../gr-diff-comment-thread/gr-diff-comment-thread.html">
<link rel="import" href="../gr-diff-comment-thread-group/gr-diff-comment-thread-group.html">
<link rel="import" href="../gr-diff-processor/gr-diff-processor.html">
<link rel="import" href="../gr-ranged-comment-layer/gr-ranged-comment-layer.html">
<link rel="import" href="../gr-syntax-layer/gr-syntax-layer.html">

<dom-module id="gr-diff-builder">
  <template>
    <div class="contentWrapper">
      <content></content>
    </div>
    <gr-ranged-comment-layer
        id="rangeLayer"
        comments="[[comments]]"></gr-ranged-comment-layer>
    <gr-syntax-layer
        id="syntaxLayer"
        diff="[[diff]]"></gr-syntax-layer>
    <gr-diff-processor
        id="processor"
        groups="{{_groups}}"></gr-diff-processor>
    <gr-reporting id="reporting"></gr-reporting>
  </template>
  <script src="../gr-diff/gr-diff-line.js"></script>
  <script src="../gr-diff/gr-diff-group.js"></script>
  <script src="../gr-diff-highlight/gr-annotation.js"></script>
  <script src="gr-diff-builder.js"></script>
  <script src="gr-diff-builder-side-by-side.js"></script>
  <script src="gr-diff-builder-unified.js"></script>
  <script src="gr-diff-builder-image.js"></script>
  <script>
    (function() {
      'use strict';

      var DiffViewMode = {
        SIDE_BY_SIDE: 'SIDE_BY_SIDE',
        UNIFIED: 'UNIFIED_DIFF',
      };

      var TimingLabel = {
        TOTAL: 'Diff Total Render',
        CONTENT: 'Diff Content Render',
        SYNTAX: 'Diff Syntax Render',
      };

      // If any line of the diff is more than the character limit, then disable
      // syntax highlighting for the entire file.
      var SYNTAX_MAX_LINE_LENGTH = 500;

      var TRAILING_WHITESPACE_PATTERN = /\s+$/;

      Polymer({
        is: 'gr-diff-builder',

        /**
         * Fired when the diff begins rendering.
         *
         * @event render-start
         */

        /**
         * Fired when the diff is rendered.
         *
         * @event render
         */

        /**
         * Fired when the diff finishes rendering text content, but not
         * necessarily syntax highlights.
         *
         * @event render-content
         */

        properties: {
          diff: Object,
          viewMode: String,
          comments: Object,
          isImageDiff: Boolean,
          baseImage: Object,
          revisionImage: Object,
          _builder: Object,
          _groups: Array,
          _layers: Array,
          _showTabs: Boolean,
        },

        get diffElement() {
          return this.queryEffectiveChildren('#diffTable');
        },

        observers: [
          '_groupsChanged(_groups.splices)',
        ],

        attached: function() {
          // Setup annotation layers.
          this._layers = [
            this._createTrailingWhitespaceLayer(),
            this.$.syntaxLayer,
            this._createIntralineLayer(),
            this._createTabIndicatorLayer(),
            this.$.rangeLayer,
          ];

          this.async(function() {
            this._preRenderThread();
          });
        },

        render: function(comments, prefs) {
          this.$.syntaxLayer.enabled = prefs.syntax_highlighting;
          this._showTabs = !!prefs.show_tabs;
          this._showTrailingWhitespace = !!prefs.show_whitespace_errors;

          // Stop the processor (if it's running).
          this.$.processor.cancel();
          this.$.syntaxLayer.cancel();

          this._builder = this._getDiffBuilder(this.diff, comments, prefs);

          this.$.processor.context = prefs.context;
          this.$.processor.keyLocations = this._getCommentLocations(comments);

          this._clearDiffContent();
          this._builder.addColumns(this.diffElement, prefs.font_size);

          var reporting = this.$.reporting;

          reporting.time(TimingLabel.TOTAL);
          reporting.time(TimingLabel.CONTENT);
          this.dispatchEvent(new CustomEvent('render-start', {bubbles: true}));
          return this.$.processor.process(this.diff.content, this.isImageDiff)
              .then(function() {
            if (this.isImageDiff) {
              this._builder.renderDiffImages();
            }
            this.dispatchEvent(new CustomEvent('render-content',
                {bubbles: true}));

            if (this._anyLineTooLong()) {
              this.$.syntaxLayer.enabled = false;
            }

            reporting.timeEnd(TimingLabel.CONTENT);
            reporting.time(TimingLabel.SYNTAX);
            return this.$.syntaxLayer.process().then(function() {
              reporting.timeEnd(TimingLabel.SYNTAX);
              reporting.timeEnd(TimingLabel.TOTAL);
              this.dispatchEvent(new CustomEvent('render', {bubbles: true}));
            }.bind(this));
          }.bind(this));
        },

        getLineElByChild: function(node) {
          while (node) {
            if (node instanceof Element) {
              if (node.classList.contains('lineNum')) {
                return node;
              }
              if (node.classList.contains('section')) {
                return null;
              }
            }
            node = node.previousSibling || node.parentElement;
          }
          return null;
        },

        getLineNumberByChild: function(node) {
          var lineEl = this.getLineElByChild(node);
          return lineEl ?
              parseInt(lineEl.getAttribute('data-value'), 10) : null;
        },

        getContentByLine: function(lineNumber, opt_side, opt_root) {
          return this._builder.getContentByLine(lineNumber, opt_side, opt_root);
        },

        getContentByLineEl: function(lineEl) {
          var root = Polymer.dom(lineEl.parentElement);
          var side = this.getSideByLineEl(lineEl);
          var line = lineEl.getAttribute('data-value');
          return this.getContentByLine(line, side, root);
        },

        getLineElByNumber: function(lineNumber, opt_side) {
          var sideSelector = !!opt_side ? ('.' + opt_side) : '';
          return this.diffElement.querySelector(
              '.lineNum[data-value="' + lineNumber + '"]' + sideSelector);
        },

        getContentsByLineRange: function(startLine, endLine, opt_side) {
          var result = [];
          this._builder.findLinesByRange(startLine, endLine, opt_side, null,
              result);
          return result;
        },

        getSideByLineEl: function(lineEl) {
          return lineEl.classList.contains(GrDiffBuilder.Side.RIGHT) ?
              GrDiffBuilder.Side.RIGHT : GrDiffBuilder.Side.LEFT;
        },

        createCommentThreadGroup: function(changeNum, patchNum, path,
            isOnParent, commentSide, projectConfig) {
          return this._builder.createCommentThreadGroup(changeNum, patchNum,
              path, isOnParent, commentSide, projectConfig);
        },

        emitGroup: function(group, sectionEl) {
          this._builder.emitGroup(group, sectionEl);
        },

        showContext: function(newGroups, sectionEl) {
          var groups = this._builder.groups;
          // TODO(viktard): Polyfill findIndex for IE10.
          var contextIndex = groups.findIndex(function(group) {
            return group.element == sectionEl;
          });
          groups.splice.apply(groups, [contextIndex, 1].concat(newGroups));

          newGroups.forEach(function(newGroup) {
            this._builder.emitGroup(newGroup, sectionEl);
          }, this);
          sectionEl.parentNode.removeChild(sectionEl);

          this.async(function() {
            this.fire('render');
          }, 1);
        },

        _getDiffBuilder: function(diff, comments, prefs) {
          if (this.isImageDiff) {
            return new GrDiffBuilderImage(diff, comments, prefs,
                this.diffElement, this.baseImage, this.revisionImage);
          } else if (this.viewMode === DiffViewMode.SIDE_BY_SIDE) {
            return new GrDiffBuilderSideBySide(
                diff, comments, prefs, this.diffElement, this._layers);
          } else if (this.viewMode === DiffViewMode.UNIFIED) {
            return new GrDiffBuilderUnified(
                diff, comments, prefs, this.diffElement, this._layers);
          }
          throw Error('Unsupported diff view mode: ' + this.viewMode);
        },

        _clearDiffContent: function() {
          this.diffElement.innerHTML = null;
        },

        _getCommentLocations: function(comments) {
          var result = {
            left: {},
            right: {},
          };
          for (var side in comments) {
            if (side !== GrDiffBuilder.Side.LEFT &&
                side !== GrDiffBuilder.Side.RIGHT) {
              continue;
            }
            comments[side].forEach(function(c) {
              result[side][c.line || GrDiffLine.FILE] = true;
            });
          }
          return result;
        },

        _groupsChanged: function(changeRecord) {
          if (!changeRecord) { return; }
          changeRecord.indexSplices.forEach(function(splice) {
            var group;
            for (var i = 0; i < splice.addedCount; i++) {
              group = splice.object[splice.index + i];
              this._builder.groups.push(group);
              this._builder.emitGroup(group);
            }
          }, this);
        },

        _createIntralineLayer: function() {
          return {
            // Take a DIV.contentText element and a line object with intraline
            // differences to highlight and apply them to the element as
            // annotations.
            annotate: function(el, line) {
              var HL_CLASS = 'style-scope gr-diff intraline';
              line.highlights.forEach(function(highlight) {
                // The start and end indices could be the same if a highlight is
                // meant to start at the end of a line and continue onto the
                // next one. Ignore it.
                if (highlight.startIndex === highlight.endIndex) { return; }

                // If endIndex isn't present, continue to the end of the line.
                var endIndex = highlight.endIndex === undefined ?
                    line.text.length : highlight.endIndex;

                GrAnnotation.annotateElement(
                    el,
                    highlight.startIndex,
                    endIndex - highlight.startIndex,
                    HL_CLASS);
              });
            },
          };
        },

        _createTabIndicatorLayer: function() {
          var show = function() { return this._showTabs; }.bind(this);
          return {
            annotate: function(el, line) {
              // If visible tabs are disabled, do nothing.
              if (!show()) { return; }

              // Find and annotate the locations of tabs.
              var split = line.text.split('\t');
              if (!split) { return; }
              for (var i = 0, pos = 0; i < split.length - 1; i++) {
                // Skip forward by the length of the content
                pos += split[i].length;

                GrAnnotation.annotateElement(el, pos, 1,
                    'style-scope gr-diff tab-indicator');

                // Skip forward by one tab character.
                pos++;
              }
            },
          };
        },

        _createTrailingWhitespaceLayer: function() {
          var show = function() {
            return this._showTrailingWhitespace;
          }.bind(this);

          return {
            annotate: function(el, line) {
              if (!show()) { return; }

              var match = line.text.match(TRAILING_WHITESPACE_PATTERN);
              if (match) {
                // Normalize string positions in case there is unicode before or
                // within the match.
                var index = GrAnnotation.getStringLength(
                    line.text.substr(0, match.index));
                var length = GrAnnotation.getStringLength(match[0]);
                GrAnnotation.annotateElement(el, index, length,
                    'style-scope gr-diff trailing-whitespace');
              }
            },
          };
        },

        /**
         * In pages with large diffs, creating the first comment thread can be
         * slow because nested Polymer elements (particularly
         * iron-autogrow-textarea) add style elements to the document head,
         * which, in turn, triggers a reflow on the page. Create a hidden
         * thread, attach it to the page, and remove it so the stylesheet will
         * already exist and the user's comment will be quick to load.
         * @see https://gerrit-review.googlesource.com/c/82213/
         */
        _preRenderThread: function() {
          var thread = document.createElement('gr-diff-comment-thread');
          thread.setAttribute('hidden', true);
          thread.addDraft();
          var parent = Polymer.dom(this.root);
          parent.appendChild(thread);
          Polymer.dom.flush();
          parent.removeChild(thread);
        },

        /**
         * @return {Boolean} whether any of the lines in _groups are longer
         * than SYNTAX_MAX_LINE_LENGTH.
         */
        _anyLineTooLong: function() {
          return this._groups.reduce(function(acc, group) {
            return acc || group.lines.reduce(function(acc, line) {
              return acc || line.text.length >= SYNTAX_MAX_LINE_LENGTH;
            }, false);
          }, false);
        },
      });
    })();
  </script>
</dom-module>