1 files changed, 211 insertions, 0 deletions
diff --git a/browser/components/newtab/PlacesProvider.jsm b/browser/components/newtab/PlacesProvider.jsm
new file mode 100644
index 000000000..f478b5c5c
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+++ b/browser/components/newtab/PlacesProvider.jsm
@@ -0,0 +1,211 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* global XPCOMUtils, Services, PlacesUtils, EventEmitter */
+/* global gLinks */
+/* exported PlacesProvider */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = ["PlacesProvider"];
+
+const {interfaces: Ci, utils: Cu} = Components;
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "PlacesUtils",
+  "resource://gre/modules/PlacesUtils.jsm");
+
+XPCOMUtils.defineLazyGetter(this, "EventEmitter", function() {
+  const {EventEmitter} = Cu.import("resource://devtools/shared/event-emitter.js", {});
+  return EventEmitter;
+});
+
+XPCOMUtils.defineLazyModuleGetter(this, "Task",
+                                  "resource://gre/modules/Task.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "NewTabUtils",
+                                  "resource://gre/modules/NewTabUtils.jsm");
+
+// The maximum number of results PlacesProvider retrieves from history.
+const HISTORY_RESULTS_LIMIT = 100;
+
+/* Queries history to retrieve the most visited sites. Emits events when the
+ * history changes.
+ * Implements the EventEmitter interface.
+ */
+let Links = function Links() {
+  EventEmitter.decorate(this);
+};
+
+Links.prototype = {
+  /**
+   * Set this to change the maximum number of links the provider will provide.
+   */
+  get maxNumLinks() {
+    // getter, so it can't be replaced dynamically
+    return HISTORY_RESULTS_LIMIT;
+  },
+
+  /**
+   * A set of functions called by @mozilla.org/browser/nav-historyservice
+   * All history events are emitted from this object.
+   */
+  historyObserver: {
+    onDeleteURI: function historyObserver_onDeleteURI(aURI) {
+      // let observers remove sensetive data associated with deleted visit
+      gLinks.emit("deleteURI", {
+        url: aURI.spec,
+      });
+    },
+
+    onClearHistory: function historyObserver_onClearHistory() {
+      gLinks.emit("clearHistory");
+    },
+
+    onFrecencyChanged: function historyObserver_onFrecencyChanged(aURI,
+                           aNewFrecency, aGUID, aHidden, aLastVisitDate) { // jshint ignore:line
+      // The implementation of the query in getLinks excludes hidden and
+      // unvisited pages, so it's important to exclude them here, too.
+      if (!aHidden && aLastVisitDate &&
+          NewTabUtils.linkChecker.checkLoadURI(aURI.spec)) {
+        gLinks.emit("linkChanged", {
+          url: aURI.spec,
+          frecency: aNewFrecency,
+          lastVisitDate: aLastVisitDate,
+          type: "history",
+        });
+      }
+    },
+
+    onManyFrecenciesChanged: function historyObserver_onManyFrecenciesChanged() {
+      // Called when frecencies are invalidated and also when clearHistory is called
+      // See toolkit/components/places/tests/unit/test_frecency_observers.js
+      gLinks.emit("manyLinksChanged");
+    },
+
+    onTitleChanged: function historyObserver_onTitleChanged(aURI, aNewTitle) {
+      if (NewTabUtils.linkChecker.checkLoadURI(aURI.spec)) {
+        gLinks.emit("linkChanged", {
+          url: aURI.spec,
+          title: aNewTitle
+        });
+      }
+    },
+
+    QueryInterface: XPCOMUtils.generateQI([Ci.nsINavHistoryObserver,
+                                           Ci.nsISupportsWeakReference])
+  },
+
+  /**
+   * Must be called before the provider is used.
+   * Makes it easy to disable under pref
+   */
+  init: function PlacesProvider_init() {
+    try {
+      PlacesUtils.history.addObserver(this.historyObserver, true);
+    } catch (e) {
+      Cu.reportError(e);
+    }
+  },
+
+  /**
+   * Gets the current set of links delivered by this provider.
+   *
+   * @returns {Promise} Returns a promise with the array of links as payload.
+   */
+  getLinks: Task.async(function*() {
+    // Select a single page per host with highest frecency, highest recency.
+    // Choose N top such pages. Note +rev_host, to turn off optimizer per :mak
+    // suggestion.
+    let sqlQuery = `SELECT url, title, frecency,
+                          last_visit_date as lastVisitDate,
+                          "history" as type
+                   FROM moz_places
+                   WHERE frecency in (
+                     SELECT MAX(frecency) as frecency
+                     FROM moz_places
+                     WHERE hidden = 0 AND last_visit_date NOTNULL
+                     GROUP BY +rev_host
+                     ORDER BY frecency DESC
+                     LIMIT :limit
+                   )
+                   GROUP BY rev_host HAVING MAX(lastVisitDate)
+                   ORDER BY frecency DESC, lastVisitDate DESC, url`;
+
+    let links = yield this.executePlacesQuery(sqlQuery, {
+                  columns: ["url", "title", "lastVisitDate", "frecency", "type"],
+                  params: {limit: this.maxNumLinks}
+                });
+
+    return links.filter(link => NewTabUtils.linkChecker.checkLoadURI(link.url));
+  }),
+
+  /**
+   * Executes arbitrary query against places database
+   *
+   * @param {String} aSql
+   *        SQL query to execute
+   * @param {Object} [optional] aOptions
+   *        aOptions.columns - an array of column names. if supplied the returned
+   *        items will consist of objects keyed on column names. Otherwise
+   *        an array of raw values is returned in the select order
+   *        aOptions.param - an object of SQL binding parameters
+   *        aOptions.callback - a callback to handle query rows
+   *
+   * @returns {Promise} Returns a promise with the array of retrieved items
+   */
+  executePlacesQuery: Task.async(function*(aSql, aOptions={}) {
+    let {columns, params, callback} = aOptions;
+    let items = [];
+    let queryError = null;
+    let conn = yield PlacesUtils.promiseDBConnection();
+    yield conn.executeCached(aSql, params, aRow => {
+      try {
+        // check if caller wants to handle query raws
+        if (callback) {
+          callback(aRow);
+        }
+        // otherwise fill in the item and add items array
+        else {
+          let item = null;
+          // if columns array is given construct an object
+          if (columns && Array.isArray(columns)) {
+            item = {};
+            columns.forEach(column => {
+              item[column] = aRow.getResultByName(column);
+            });
+          } else {
+            // if no columns - make an array of raw values
+            item = [];
+            for (let i = 0; i < aRow.numEntries; i++) {
+              item.push(aRow.getResultByIndex(i));
+            }
+          }
+          items.push(item);
+        }
+      } catch (e) {
+        queryError = e;
+        throw StopIteration;
+      }
+    });
+    if (queryError) {
+      throw new Error(queryError);
+    }
+    return items;
+  }),
+};
+
+/**
+ * Singleton that serves as the default link provider for the grid.
+ */
+const gLinks = new Links(); // jshint ignore:line
+
+let PlacesProvider = {
+  links: gLinks,
+};
+
+// Kept only for backwards-compatibility
+XPCOMUtils.defineLazyGetter(PlacesProvider, "LinkChecker",
+  () => NewTabUtils.linkChecker);
+