PrintPreview: Preview generation should not block print button.

chrome/browser/resources/print_preview.js

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var localStrings = new LocalStrings();
 
 // The total page count of the previewed document regardless of which pages the
 // user has selected.
 var totalPageCount = -1;
 
@@ skipping 12 matching lines @@
 // Used to disable some printing options when the preview is not modifiable.
 var previewModifiable = false;
 
 // Destination list special value constants.
 const PRINT_TO_PDF = 'Print To PDF';
 const MANAGE_PRINTERS = 'Manage Printers';
 
 // State of the print preview settings.
 var printSettings = new PrintSettings();
 
+// Total number of print preview requests submitted.

[dpapad, 2011/06/06 20:47:43]

This variable is being decremented in updatePrintPreview(). Change the comment
to "Total number of in-flight print preview requests submitted." or something
else to this effect.

[kmadhusu, 2011/06/06 21:23:56]

Done.

+var previewRequestCount = 0;
+
+// True when a pending print file request exists.
+var hasPendingPrintFileRequest = false;

[dpapad, 2011/06/06 20:47:43]

This variable is calculated based on previewRequestCount. I would prefer
removing it and checking directly for previewRequestCount > 0 wherever needed.

[kmadhusu, 2011/06/06 21:23:56]

(just repeating our in-person conversation) I need this global variable. It is
modified in printFile() function. It is used to track whether a printFile
request is submitted earlier while a preview data is loading.

+
 /**
  * Window onload handler, sets up the page and starts print preview by getting
  * the printer list.
  */
 function onLoad() {
-  $('system-dialog-link').addEventListener('click', showSystemDialog);
   $('cancel-button').addEventListener('click', handleCancelButtonClick);
 
   if (!checkCompatiblePluginExists()) {
     displayErrorMessage(localStrings.getString('noPlugin'), false);
     $('mainview').parentElement.removeChild($('dummy-viewer'));
+    $('print-button').addEventListener('click', showSystemDialog);

[dpapad, 2011/06/06 20:47:43]

I think for now it is better to add this listener $('system-dialog-link') as
before (until we hear back from the UI people).

[kmadhusu, 2011/06/06 21:23:56]

Done.

     return;
   }
+  $('system-dialog-link').addEventListener('click', showSystemDialog);
   $('mainview').parentElement.removeChild($('dummy-viewer'));
 
   $('printer-list').disabled = true;
-  $('print-button').disabled = true;
+  $('print-button').onclick = printFile;
+
+  addEventListenersToPagesControls();
+  addEventListenersToCopiesControls();
   showLoadingAnimation();
   chrome.send('getDefaultPrinter');
 }
 
 /**
- * Adds event listeners to the settings controls.
+ * Adds event listeners to the pages section controls.
  */
-function addEventListeners() {
-  $('print-button').onclick = printFile;
-
-  // Controls that require preview rendering.
+function addEventListenersToPagesControls() {
   $('all-pages').onclick = onPageSelectionMayHaveChanged;
   $('print-pages').onclick = handleIndividualPagesCheckbox;
   var individualPages = $('individual-pages');
   individualPages.onblur = function() {
       clearTimeout(timerId);
       onPageSelectionMayHaveChanged();
   };
   individualPages.onfocus = addTimerToPageRangeField;
   individualPages.oninput = resetPageRangeFieldTimer;
-  $('landscape').onclick = onLayoutModeToggle;
-  $('portrait').onclick = onLayoutModeToggle;
-  $('printer-list').onchange = updateControlsWithSelectedPrinterCapabilities;
+}
 
-  // Controls that dont require preview rendering.
+/**
+ * Adds event listeners to the copies controls.
+ */
+function addEventListenersToCopiesControls() {
   $('copies').oninput = function() {
     copiesFieldChanged();
     updatePrintButtonState();
     updatePrintSummary();
   };
-  $('two-sided').onclick = handleTwoSidedClick;
-  $('color').onclick = function() { setColor(true); };
-  $('bw').onclick = function() { setColor(false); };
   $('increment').onclick = function() {
     onCopiesButtonsClicked(1);
     updatePrintButtonState();
     updatePrintSummary();
   };
   $('decrement').onclick = function() {
     onCopiesButtonsClicked(-1);
     updatePrintButtonState();
     updatePrintSummary();
   };
 }
 
 /**
+ * Adds event listeners to the settings controls.
+ */
+function addEventListeners() {
+  // Controls that require preview rendering.
+  $('landscape').onclick = onLayoutModeToggle;
+  $('portrait').onclick = onLayoutModeToggle;
+  $('printer-list').onchange = updateControlsWithSelectedPrinterCapabilities;
+
+  // Controls that dont require preview rendering.
+  $('two-sided').onclick = handleTwoSidedClick;
+  $('color').onclick = function() { setColor(true); };
+  $('bw').onclick = function() { setColor(false); };
+}
+
+/**
  * Removes event listeners from the settings controls.
  */
 function removeEventListeners() {
   // Controls that require preview rendering.
-  $('print-button').disabled = true;
-  $('all-pages').onclick = null;
-  $('print-pages').onclick = null;
-  var individualPages = $('individual-pages');
-  individualPages.onblur = null;
-  individualPages.onfocus = null;
-  individualPages.oninput = null;
-  clearTimeout(timerId);
   $('landscape').onclick = null;
   $('portrait').onclick = null;
   $('printer-list').onchange = null;
 
   // Controls that dont require preview rendering.
-  $('copies').oninput = copiesFieldChanged;
   $('two-sided').onclick = null;
   $('color').onclick = null;
   $('bw').onclick = null;
-  $('increment').onclick = function() { onCopiesButtonsClicked(1); };
-  $('decrement').onclick = function() { onCopiesButtonsClicked(-1); };
 }
 
 /**
  * Asks the browser to close the preview tab.
  */
 function handleCancelButtonClick() {
   chrome.send('closePrintPreviewTab');
 }
 
 /**
  * Asks the browser to show the native print dialog for printing.
  */
 function showSystemDialog() {
   chrome.send('showSystemDialog');
 }
 
 /**
  * Disables the controls which need the initiator tab to generate preview
  * data. This function is called when the initiator tab is closed.
  * @param {string} initiatorTabURL The URL of the initiator tab.
  */
 function onInitiatorTabClosed(initiatorTabURL) {
   $('reopen-page').addEventListener('click', function() {
       window.location = initiatorTabURL;
   });
   displayErrorMessage(localStrings.getString('initiatorTabClosed'), true);
+  $('print-button').disabled = true;
 }
 
 /**
  * Gets the selected printer capabilities and updates the controls accordingly.
  */
 function updateControlsWithSelectedPrinterCapabilities() {
   var printerList = $('printer-list');
   var selectedIndex = printerList.selectedIndex;
   if (selectedIndex < 0)
     return;
@@ skipping 164 matching lines @@
   var deviceName = '';
   if (selectedPrinter >= 0)
     deviceName = printerList.options[selectedPrinter].value;
   return deviceName;
 }
 
 /**
  * Asks the browser to print the preview PDF based on current print settings.
  */
 function printFile() {
+  hasPendingPrintFileRequest = previewRequestCount > 0;
+
+  if (hasPendingPrintFileRequest) {
+    if (getSelectedPrinterName() != PRINT_TO_PDF)
+      chrome.send('hidePreview');
+    return;
+  }
+
   if (getSelectedPrinterName() != PRINT_TO_PDF) {
     $('print-button').classList.add('loading');
     $('cancel-button').classList.add('loading');
     $('print-summary').innerHTML = localStrings.getString('printing');
     removeEventListeners();
     window.setTimeout(function() { chrome.send('print', [getSettingsJSON()]); },
                       1000);
-  } else
+  } else {
     chrome.send('print', [getSettingsJSON()]);
+  }
 }
 
 /**
  * Asks the browser to generate a preview PDF based on current print settings.
  */
 function requestPrintPreview() {
+  previewRequestCount++;
   removeEventListeners();
   printSettings.save();
   showLoadingAnimation();
   chrome.send('getPreview', [getSettingsJSON()]);
 }
 
 /**
  * Set the default printer. If there is one, generate a print preview.
  * @param {string} printer Name of the default printer. Empty if none.
  */
@@ skipping 135 matching lines @@
  * @param {number} pageCount The expected total pages count.
  * @param {string} jobTitle The print job title.
  * @param {boolean} modifiable If the preview is modifiable.
  * @param {string} previewUid Preview unique identifier.
  */
 function updatePrintPreview(pageCount, jobTitle, modifiable, previewUid) {
   var tempPrintSettings = new PrintSettings();
   tempPrintSettings.save();
 
   previewModifiable = modifiable;
 

[dpapad, 2011/06/06 20:47:43]

Add "var hasPendingPrintFileRequest = previewRequestCount > 0;" here since
hasPendingPrintFileRequest is no longer global (in case you followed my earlier
comment).

[kmadhusu, 2011/06/06 21:23:56]

Please refer to my reply for your earlier comment.

+  if (previewRequestCount > 0)
+    previewRequestCount--;
+
   if (totalPageCount == -1)
     totalPageCount = pageCount;
 
   if (previouslySelectedPages.length == 0)
     for (var i = 0; i < totalPageCount; i++)
       previouslySelectedPages.push(i+1);
 
   if (printSettings.deviceName != tempPrintSettings.deviceName) {
     updateControlsWithSelectedPrinterCapabilities();
     return;
   } else if (printSettings.isLandscape != tempPrintSettings.isLandscape) {
     setDefaultValuesAndRegeneratePreview();
     return;
   } else if (getSelectedPagesValidityLevel() == 1) {
     var currentlySelectedPages = getSelectedPagesSet();
     if (!areArraysEqual(previouslySelectedPages, currentlySelectedPages)) {
       previouslySelectedPages = currentlySelectedPages;
       requestPrintPreview();
       return;
     }
   }
 
   if (getSelectedPagesValidityLevel() != 1)
     pageRangesFieldChanged();
 
   // Update the current tab title.
   document.title = localStrings.getStringF('printPreviewTitleFormat', jobTitle);
 
   createPDFPlugin(previewUid);
+
+  if (previewRequestCount == 0 && hasPendingPrintFileRequest) {
+    printFile();
+    return;
+  }
+
   updatePrintSummary();
   updatePrintButtonState();
   addEventListeners();
 }
 
 /**
  * Create the PDF plugin or reload the existing one.
  * @param {string} previewUid Preview unique identifier.
  */
 function createPDFPlugin(previewUid) {
@@ skipping 425 matching lines @@
   this.isLandscape = '';
 }
 
 /**
  * Takes a snapshot of the print settings.
  */
 PrintSettings.prototype.save = function() {
   this.deviceName = getSelectedPrinterName();
   this.isLandscape = isLandscape();
 }