Support moz-action:switchtotab

[piroor]

http://mxr.mozilla.org/mozilla-central/source/toolkit/components/places/nsPlacesAutoComplete.js#1065

1065   _processRow: function PAC_processRow(aRow)
1066   {
...
1070     let openPageCount = aRow.getResultByIndex(kQueryIndexOpenPageCount) || 0;
1071 
1072     // If actions are enabled and the page is open, add only the switch-to-tab
1073     // result.  Otherwise, add the normal result.
1074     let [url, action] = this._enableActions && openPageCount > 0 ?
1075                         ["moz-action:switchtab," + escapedEntryURL, "action "] :
1076                         [escapedEntryURL, ""];

The count is registered by this SQL:
http://mxr.mozilla.org/mozilla-central/source/toolkit/components/places/nsPlacesAutoComplete.js#460

460   this._registerOpenPageQuerySQL = "INSERT OR REPLACE INTO moz_openpages_temp "
461                                  +   "(url, open_count) "
462                                  + "VALUES (:page_url, "
463                                  +   "IFNULL("
464                                  +     "("
465                                  +        "SELECT open_count + 1 "
466                                  +        "FROM moz_openpages_temp "
467                                  +        "WHERE url = :page_url "
468                                  +      "), "
469                                  +     "1"
470                                  +   ")"
471                                  + ")";
472   XPCOMUtils.defineLazyGetter(this, "_registerOpenPageQuery", function() {
473     return this._db.createAsyncStatement(this._registerOpenPageQuerySQL);
474   });

However, the table moz_openpages_temp is in an inaccessible connection.

http://mxr.mozilla.org/mozilla-central/source/toolkit/components/places/nsPlacesAutoComplete.js#302

302   XPCOMUtils.defineLazyGetter(this, "_db", function() {
303     // Get a cloned, read-only version of the database.  We'll only ever write
304     // to our own in-memory temp table, and having a cloned copy means we do not
305     // run the risk of our queries taking longer due to the main database
306     // connection performing a long-running task.
307     let db = Cc["@mozilla.org/browser/nav-history-service;1"].
308              getService(Ci.nsPIPlacesDatabase).
309              DBConnection.
310              clone(true);
...
319     // Create our in-memory tables for tab tracking.
320     initTempTable(db);

[piroor]

http://mxr.mozilla.org/mozilla-central/source/browser/base/content/tabbrowser.xml#622

623                 if (this.mBrowser.registeredOpenURI) {
624                   autocomplete.unregisterOpenPage(this.mBrowser.registeredOpenURI);
625                   delete this.mBrowser.registeredOpenURI;
626                 }
627                 if (!isBlankPageURL(aLocation.spec)
628 #ifdef MOZ_PER_WINDOW_PRIVATE_BROWSING
629                     // Tabs in private windows aren't registered as "Open" so
630                     // that they don't appear as switch-to-tab candidates.
631                     && !PrivateBrowsingUtils.isWindowPrivate(window)
632 #endif
633                     ) {
634                   autocomplete.registerOpenPage(aLocation);
635                   this.mBrowser.registeredOpenURI = aLocation;

Open page count is updated on "onLocationChange" of tab progress listeners. By custom tab progress listeners, we can emulate it.

[piroor]

It is too much: adding progress listeners for the location bar. Is there any alternative way?

Points:

• On searching, we have to restrict search results to "only open pages".
  Is it possible that list open pages quickly without temporary table?
• On listing, we have to use "moz-action:" URI instead of normal URI.
  Is it possible that checking open state of a page without temporary table?

[piroor]

Currently there is no way, because:

• It is an XPCOM component, not a JS code module. So, we have no way to access the instance having internal property "_db".
• There is no API to get open count. Firefox gets the count directly by SQL.