Refactor print preview web ui

chrome/browser/resources/print_preview/preview_generator.js

+// Copyright (c) 2012 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.
+
+cr.define('print_preview', function() {
+  'use strict';
+
+  /**
+   * Interface to the Chromium print preview generator.
+   *
+   * @param {print_preview.PrintTicketStore!} printTicketStore Used to read the
+   *     state of the ticket and write document information.
+   * @constructor
+   * @extends {cr.EventTarget}
+   */
+  function PreviewGenerator(printTicketStore) {
+    cr.EventTarget.call(this);
+
+    /**
+     * Used to read the state of the ticket and write document information.
+     * @type {print_preview.PrintTicketStore!}
+     * @private
+     */
+    this.printTicketStore_ = printTicketStore;
+
+    /**
+     * ID of current in-flight request. Requests that do not share this ID will
+     * be ignored.
+     * @type {number}
+     * @private
+     */
+    this.inFlightRequestId_ = -1;
+
+    /**
+     * Whether the previews are being generated in landscape mode.
+     * @type {boolean}
+     * @private
+     */
+    this.isLandscapeEnabled_ = false;
+
+    /**
+     * Whether the previews are being generated with a header and footer.
+     * @type {boolean}
+     * @private
+     */
+    this.isHeaderFooterEnabled_ = false;
+
+    /**
+     * Whether the previews are being generated in color.
+     * @type {boolean}
+     * @private
+     */
+    this.isColorEnabled_ = false;
+
+    /**
+     * Page number set used to generate the last preview.
+     * @type {print_preview.PageNumberSet}
+     * @private
+     */
+    this.pageNumberSet_ = null;
+
+    /**
+     * Event tracker used to keep track of native layer events.
+     * @type {EventTracker}
+     * @private
+     */
+    this.tracker_ = new EventTracker();
+
+    this.addEventListeners_();
+  };
+
+  /**
+   * Events dispatched by the preview generator.
+   * @enum {string}
+   */
+  PreviewGenerator.Event = {
+    // Dispatched when the document can be printed.
+    DOCUMENT_READY: 'print_preview.PreviewGenerator.DOCUMENT_READY',
+
+    // Dispatched when a page preview is ready. The previewIndex field of the
+    // event is the index of the page in the modified document, not the
+    // original. So page 4 of the original document might be previewIndex = 0 of
+    // the modified document.
+    PAGE_READY: 'print_preview.PreviewGenerator.PAGE_READY',
+
+    // Dispatched when the current print preview request fails.
+    FAIL: 'print_preview.PreviewGenerator.FAIL'
+  };
+
+  PreviewGenerator.prototype = {
+    __proto__: cr.EventTarget.prototype,
+
+    /** @override */
+    dispatchEvent: function(evt) {
+      // TODO REMOVE ME
+      log(evt.type);
+      cr.EventTarget.prototype.dispatchEvent.call(this, evt);
+    },
+
+    /**
+     * Request that new preview be generated. A preview request will not be
+     * generated if the print ticket has not changed sufficiently.
+     */
+    requestPreview: function() {
+      if (this.hasPreviewChanged_()) {
+        log('print_preview.PreviewGenerator.requestPreview');
+        this.isLandscapeEnabled_ = this.printTicketStore_.isLandscapeEnabled();
+        this.isHeaderFooterEnabled_ =
+            this.printTicketStore_.isHeaderFooterEnabled();
+        this.isColorEnabled_ = this.printTicketStore_.isColorEnabled();
+        this.pageNumberSet_ = this.printTicketStore_.getPageNumberSet();
+        // TODO Update margins
+        this.inFlightRequestId_++;
+        // TODO Maybe move some of these ticket fields into nativeLayer API.
+        var ticket = this.printTicketStore_.createTicketForPreviewGenerator();
+        ticket['requestID'] = this.inFlightRequestId_;
+        ticket['isFirstRequest'] = this.inFlightRequestId_ == 0;
+        nativeLayer.startGetPreview(
+            JSON.stringify(ticket),
+            this.inFlightRequestId_ == 0 ? -1 : this.printTicketStore_.pageCount,
+                //this.printTicketStore_.getPageNumberSet().size,
+            this.printTicketStore_.isDocumentModifiable);
+      }
+    },
+
+    /**
+     * Adds event listeners to the relevant native layer events.
+     * @private
+     */
+    addEventListeners_: function() {
+      this.tracker_.add(
+          nativeLayer,
+          print_preview.NativeLayer.Event.PAGE_LAYOUT_CHANGE,
+          this.onPageLayoutChange_.bind(this));
+      this.tracker_.add(
+          nativeLayer,
+          print_preview.NativeLayer.Event.PAGE_COUNT_CHANGE,
+          this.onPageCountChange_.bind(this));
+      this.tracker_.add(
+          nativeLayer,
+          print_preview.NativeLayer.Event.PREVIEW_RELOAD,
+          this.onPreviewReload_.bind(this));
+      this.tracker_.add(
+          nativeLayer,
+          print_preview.NativeLayer.Event.PAGE_PREVIEW_READY,
+          this.onPagePreviewReady_.bind(this));
+      this.tracker_.add(
+          nativeLayer,
+          print_preview.NativeLayer.Event.PREVIEW_GENERATION_DONE,
+          this.onPreviewGenerationDone_.bind(this));
+      this.tracker_.add(
+          nativeLayer,
+          print_preview.NativeLayer.Event.PREVIEW_GENERATION_FAIL,
+          this.onPreviewGenerationFail_.bind(this));
+    },
+
+    dispatchPageReadyEvent_: function(previewIndex, pageNumber, previewUid) {
+      var pageGenEvt = new cr.Event(PreviewGenerator.Event.PAGE_READY);
+      pageGenEvt.previewIndex = previewIndex;
+      pageGenEvt.previewUrl =
+          'chrome://print/' + previewUid + '/' + (pageNumber - 1) +
+          '/print.pdf';
+      this.dispatchEvent(pageGenEvt);
+    },
+
+    /**
+     * Called when the page layout of the document has changed.
+     * @param {cr.Event} evt Contains information about the document.
+     * @private
+     */
+    onPageLayoutChange_: function(evt) {
+      var pageLayout = evt.pageLayout;
+      var hasCustomPageSizeStyle = evt.hasCustomPageSizeStyle;
+      // NOTE: A request ID is not specified, so assuming its for the current
+      // in-flight request.
+      // TODO
+      //  hasPageSizeStyle = hasCustomPageSizeStyle;
+      //  marginSettings.currentDefaultPageLayout = new print_preview.PageLayout(
+      //      pageLayout.contentWidth,
+      //      pageLayout.contentHeight,
+      //      pageLayout.marginLeft,
+      //      pageLayout.marginTop,
+      //      pageLayout.marginRight,
+      //      pageLayout.marginBottom);
+      //  headerFooterSettings.checkAndHideHeaderFooterOption(
+      //      pageLayout, marginSettings.selectedMarginsValue);
+    },
+
+    /**
+     * Called when the document page count is received from the native layer.
+     * @param {cr.Event} evt Contains the document's page count.
+     * @private
+     */
+    onPageCountChange_: function(evt) {
+      if (this.inFlightRequestId_ != evt.previewResponseId) {
+        return; // Ignore old response.
+      }
+      this.printTicketStore_.updatePageCount(evt.pageCount);
+    },
+
+    /**
+     * Called when the print preview should be reloaded.
+     * @param {cr.Event} evt Contains the preview UID and request ID.
+     * @private
+     */
+    onPreviewReload_: function(evt) {
+      if (this.inFlightRequestId_ != evt.previewResponseId) {
+        return; // Ignore old response.
+      }
+      var pageNumberSetSize = this.printTicketStore_.getPageNumberSet().size;
+      for (var i = 0; i < pageNumberSetSize; i++) {
+        var pageNumber =
+            this.printTicketStore_.getPageNumberSet().getPageNumberAt(i);
+        log('PageReady -- idx:' + i + ' num:' + pageNumber);
+        this.dispatchPageReadyEvent_(i, pageNumber, evt.previewUid);
+      }
+    },
+
+    /**
+     * Called when a page's preview has been generated. Dispatches a
+     * PAGE_READY event.
+     * @param {cr.Event} evt Contains the page index and preview UID.
+     * @private
+     */
+    onPagePreviewReady_: function(evt) {
+      if (this.inFlightRequestId_ != evt.previewResponseId) {
+        return; // Ignore old response.
+      }
+      var pageNumber = evt.pageIndex + 1;
+      if (this.printTicketStore_.getPageNumberSet().hasPageNumber(pageNumber)) {
+        var previewIndex = this.printTicketStore_.getPageNumberSet()
+            .getPageNumberIndex(pageNumber);
+        this.dispatchPageReadyEvent_(previewIndex, pageNumber, evt.previewUid);
+      }
+    },
+
+    /**
+     * Called when the preview generation is complete. Dispatches a
+     * DOCUMENT_READY event.
+     * @param {cr.Event} evt Contains the preview UID and response ID.
+     * @private
+     */
+    onPreviewGenerationDone_: function(evt) {
+      if (this.inFlightRequestId_ != evt.previewResponseId) {
+        return; // Ignore old response.
+      }
+    },
+
+    /**
+     * Called when the preview generation fails.
+     * @private
+     */
+    onPreviewGenerationFail_: function() {
+      // NOTE: No request ID is returned from Chromium so its assumed its the
+      // current one.
+      cr.dispatchSimpleEvent(this, PreviewGenerator.Event.FAIL);
+    },
+
+    /**
+     * @return {boolean} Whether the print ticket has changed sufficiently to
+     *     determine whether a new preview request should be issued.
+     * @private
+     */
+    hasPreviewChanged_: function() {
+      var ticketStore = this.printTicketStore_;
+      var result = this.inFlightRequestId_ == -1 ||
+          ticketStore.isLandscapeEnabled() != this.isLandscapeEnabled_ ||
+          ticketStore.isHeaderFooterEnabled() != this.isHeaderFooterEnabled_ ||
+          ticketStore.isColorEnabled() != this.isColorEnabled_ ||
+          !ticketStore.getPageNumberSet().equals(this.pageNumberSet_);
+          // TODO Check margins.
+      log('print_preview.PreviewGenerator.hasPreviewChanged_: ' +
+          ticketStore.getPageNumberSet().equals(this.pageNumberSet_));
+      return result;
+    },
+  };
+
+  // Export
+  return {
+    PreviewGenerator: PreviewGenerator
+  };
+});