Truncate the number of rows displayed on about:profiler.

Rather than displaying the full table of data (which can be quite large), we instead display only 30 (when ungrouped), or just 10 when grouped.

This speeds up the rendering of the page since a much smaller number of rows need to be drawn. It also helps reduce the clutter when grouping.

The hidden rows can be displayed with the click of a button.

BUG=100992
Review URL: http://codereview.chromium.org/8574051

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@110545 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 128 insertions, 9 deletions

diff --git a/chrome/browser/resources/profiler.html b/chrome/browser/resources/profiler.html
index 273ac49..9abcdb5 100644
--- a/chrome/browser/resources/profiler.html
+++ b/chrome/browser/resources/profiler.html
@@ -51,6 +51,14 @@ table.results-table,
   background: #FFCC99;
 }
 
+/*
+ * This is the row at the end of tables which explains how many rows were shown,
+ * and how many were hidden.
+ */
+.results-table .truncation-row {
+  background: #eee;
+}
+
 /*---------------------------------------------------------------------------*/
 
 /*
diff --git a/chrome/browser/resources/profiler.js b/chrome/browser/resources/profiler.js
index 499b281..d7fe39b 100644
--- a/chrome/browser/resources/profiler.js
+++ b/chrome/browser/resources/profiler.js
@@ -541,6 +541,24 @@ var MainView = (function() {
    */
   var PROCESS_DATA_DELAY_MS = 500;
 
+  /**
+   * The initial number of rows to display (the rest are hidden) when no
+   * grouping is selected. We use a higher limit than when grouping is used
+   * since there is a lot of vertical real estate.
+   */
+  var INITIAL_UNGROUPED_ROW_LIMIT = 30;
+
+  /**
+   * The initial number of rows to display (rest are hidden) for each group.
+   */
+  var INITIAL_GROUP_ROW_LIMIT = 10;
+
+  /**
+   * The number of extra rows to show/hide when clicking the "Show more" or
+   * "Show less" buttons.
+   */
+  var LIMIT_INCREMENT = 10;
+
   // --------------------------------------------------------------------------
   // General utility functions
   // --------------------------------------------------------------------------
@@ -885,7 +903,9 @@ var MainView = (function() {
    * Renders the information for a particular group.
    */
   function drawGroup(parent, groupData, columns,
-                     columnOnClickHandler, currentSortKeys) {
+                     columnOnClickHandler, currentSortKeys, displaySettings,
+                     expandHandler, shrinkHandler, showAllHandler,
+                     showNoneHandler) {
     var div = addNode(parent, 'div');
     div.className = 'group-container';
 
@@ -894,7 +914,9 @@ var MainView = (function() {
     var table = addNode(div, 'table');
 
     drawDataTable(table, groupData, columns, columnOnClickHandler,
-                  currentSortKeys);
+                  currentSortKeys, displaySettings.limit,
+                  expandHandler, shrinkHandler, showAllHandler,
+                  showNoneHandler);
   }
 
   /**
@@ -926,14 +948,50 @@ var MainView = (function() {
    * Renders a table which summarizes all |column| fields for |data|.
    */
   function drawDataTable(table, data, columns, columnOnClickHandler,
-                         currentSortKeys) {
+                         currentSortKeys, limit, expandHandler, shrinkHandler,
+                         showAllHandler, showNoneHandler) {
     table.className = 'results-table';
     var thead = addNode(table, 'thead');
     var tbody = addNode(table, 'tbody');
 
     drawAggregateRow(thead, data.aggregates, columns);
     drawTableHeader(thead, columns, columnOnClickHandler, currentSortKeys);
-    drawTableBody(tbody, data.rows, columns);
+    drawTableBody(tbody, data.rows, columns, limit);
+    drawTruncationRow(tbody, data.rows.length, limit, columns.length,
+                      expandHandler, shrinkHandler, showAllHandler,
+                      showNoneHandler);
+  }
+
+  /**
+   * Renders a row which describes how many rows the table has, how many are
+   * currently hidden, and a set of buttons to show more.
+   */
+  function drawTruncationRow(tbody, numRows, limit, numColumns,
+                             expandHandler, shrinkHandler, showAllHandler,
+                             showNoneHandler) {
+    var numHiddenRows = Math.max(numRows - limit, 0);
+    var numVisibleRows = numRows - numHiddenRows;
+
+    var tr = addNode(tbody, 'tr');
+    tr.className = 'truncation-row';
+    var td = addNode(tr, 'td');
+    td.colSpan = numColumns;
+
+    addText(td, numRows + ' rows');
+    if (numHiddenRows > 0) {
+      var s = addNode(td, 'span', ' (' + numHiddenRows + ' hidden) ');
+      s.style.color = 'red';
+    }
+
+    if (numVisibleRows > LIMIT_INCREMENT)
+      addNode(td, 'button', 'Show less').onclick = shrinkHandler;
+    if (numVisibleRows > 0)
+      addNode(td, 'button', 'Show none').onclick = showNoneHandler;
+
+    if (numHiddenRows > 0) {
+      addNode(td, 'button', 'Show more').onclick = expandHandler;
+      addNode(td, 'button', 'Show all').onclick = showAllHandler;
+    }
   }
 
   function drawTableHeader(thead, columns, columnOnClickHandler,
@@ -1023,8 +1081,8 @@ var MainView = (function() {
     }
   }
 
-  function drawTableBody(tbody, rows, columns) {
-    for (var i = 0; i < rows.length; ++i) {
+  function drawTableBody(tbody, rows, columns, limit) {
+    for (var i = 0; i < rows.length && i < limit; ++i) {
       var e = rows[i];
 
       var tr = addNode(tbody, 'tr');
@@ -1326,10 +1384,61 @@ var MainView = (function() {
 
       // Draw each group.
       for (var i = 0; i < this.sortedGroupKeys_.length; ++i) {
-        var groupData = this.groupedData_[this.sortedGroupKeys_[i]];
-        drawGroup(parent, groupData, columns,
-                  columnOnClickHandler, this.currentSortKeys_);
+        var k = this.sortedGroupKeys_[i];
+        drawGroup(parent,
+                  this.groupedData_[k],
+                  columns,
+                  columnOnClickHandler,
+                  this.currentSortKeys_,
+                  this.getGroupDisplaySettings_(k),
+                  this.changeGroupDisplayLimit_.bind(this, k, LIMIT_INCREMENT),
+                  this.changeGroupDisplayLimit_.bind(this, k, -LIMIT_INCREMENT),
+                  this.changeGroupDisplayLimit_.bind(this, k, Infinity),
+                  this.changeGroupDisplayLimit_.bind(this, k, -Infinity));
+      }
+    },
+
+    /**
+     * Adjusts the row limit for group |groupKey| by |delta|.
+     */
+    changeGroupDisplayLimit_: function(groupKey, delta) {
+      // Get the current settings for this group.
+      var settings = this.getGroupDisplaySettings_(groupKey, true);
+
+      // Compute the adjusted limit.
+      var newLimit = settings.limit;
+      var totalNumRows = this.groupedData_[groupKey].rows.length;
+      newLimit = Math.min(totalNumRows, newLimit);
+      newLimit += delta;
+      newLimit = Math.max(0, newLimit);
+
+      // Update the settings with the new limit.
+      settings.limit = newLimit;
+
+      // TODO(eroman): It isn't necessary to redraw *all* the data. Really we
+      // just need to insert the missing rows (everything else stays the same)!
+      this.redrawData_();
+    },
+
+    /**
+     * Returns the rendering settings for group |groupKey|. This includes things
+     * like how many rows to display in the table.
+     */
+    getGroupDisplaySettings_: function(groupKey, opt_create) {
+      var settings = this.groupDisplaySettings_[groupKey];
+      if (!settings) {
+        // If we don't have any settings for this group yet, create some
+        // default ones.
+        if (groupKey == '[]') {
+          // (groupKey of '[]' is what we use for ungrouped data).
+          settings = {limit: INITIAL_UNGROUPED_ROW_LIMIT};
+        } else {
+          settings = {limit: INITIAL_GROUP_ROW_LIMIT};
+        }
+        if (opt_create)
+          this.groupDisplaySettings_[groupKey] = settings;
       }
+      return settings;
     },
 
     init_: function() {
@@ -1352,6 +1461,8 @@ var MainView = (function() {
       this.groupedData_ = {};
       this.sortedGroupKeys_ = [];
 
+      this.groupDisplaySettings_ = {};
+
       this.fillSelectionCheckboxes_($(COLUMN_TOGGLES_CONTAINER_ID));
       this.fillMergeCheckboxes_($(COLUMN_MERGE_TOGGLES_CONTAINER_ID));