Implement coarse "on demand" functionality for update checks.

chrome/browser/component_updater/component_updater_service.cc

 // 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.
 
 #include "chrome/browser/component_updater/component_updater_service.h"
 
 #include <algorithm>
 #include <set>
 #include <vector>
 
@@ skipping 45 matching lines @@
   CrxComponent::BANDAID,
   CrxComponent::CWS_PUBLIC,
   CrxComponent::CWS_SANDBOX,
 };
 
 // Extends an omaha compatible update check url |query| string. Does
 // not mutate the string if it would be longer than |limit| chars.
 bool AddQueryString(const std::string& id,
                     const std::string& version,
                     const std::string& fingerprint,
+                    bool ondemand,
                     size_t limit,
                     std::string* query) {
   std::string additional =
-      base::StringPrintf("id=%s&v=%s&fp=%s&uc",
-                         id.c_str(), version.c_str(), fingerprint.c_str());
+      base::StringPrintf("id=%s&v=%s&fp=%s&uc%s",
+                         id.c_str(),
+                         version.c_str(),
+                         fingerprint.c_str(),
+                         ondemand ? "&installsource=ondemand" : "");
   additional = "x=" + net::EscapeQueryParamValue(additional, true);
   if ((additional.size() + query->size() + 1) > limit)
     return false;
   if (!query->empty())
     query->append(1, '&');
   query->append(additional);
   return true;
 }
 
 // Create the final omaha compatible query. The |extra| is optional and can
@@ skipping 479 matching lines @@
   work_items_.push_back(uit);
   // If this is the first component registered we call Start to
   // schedule the first timer.
   if (running_ && (work_items_.size() == 1))
     Start();
 
   return kOk;
 }
 
 // Sets a component to be checked for updates.
 // The component to add is |crxit| and the |query| string is modified with the

[asargent_no_longer_on_chrome, 2013/06/24 17:34:51]

nit: should this be "|item|" instead of "|crxit|" ?

[waffles, 2013/06/24 17:39:30]

Done.

 // required omaha compatible query. Returns false when the query strings

[asargent_no_longer_on_chrome, 2013/06/24 17:34:51]

nit: "when the query strings" -> "when the query string"

[waffles, 2013/06/24 17:39:30]

Done.

 // is longer than specified by UrlSizeLimit().
 bool CrxUpdateService::AddItemToUpdateCheck(CrxUpdateItem* item,
                                             std::string* query) {
   if (!AddQueryString(item->id,
                       item->component.version.GetString(),
                       item->component.fingerprint,
-                      config_->UrlSizeLimit(), query))
+                      requested_work_items_.count(item),

[Sorin Jianu, 2013/06/24 17:25:57]

I would consider using a
const bool is_ondemand = requested_work_items_.count(item);

The code is efficient as before, with the added benefit of making explicit what
the value of the expression means. A brief code comment to explain how the
feature is intended to work would be useful as well.

[asargent_no_longer_on_chrome, 2013/06/24 17:34:51]

This is a good suggestion. A slightly more compact pattern we sometimes use as
well is to just include a comment inline with the argument you're passing, e.g.


requested_work_items_.count(item), // is_ondemand


Either way would be fine. 

[waffles, 2013/06/24 17:39:30]

Done.

+                      config_->UrlSizeLimit(),
+                      query))
     return false;
 
   item->status = CrxUpdateItem::kChecking;
   item->last_check = base::Time::Now();
   item->previous_version = item->component.version;
   item->next_version = Version();
   item->previous_fp = item->component.fingerprint;
   item->next_fp.clear();
   item->diff_update_failed = false;
   return true;
@@ skipping 405 matching lines @@
   ScheduleNextRun(false);
 }
 
 // The component update factory. Using the component updater as a singleton
 // is the job of the browser process.
 ComponentUpdateService* ComponentUpdateServiceFactory(
     ComponentUpdateService::Configurator* config) {
   DCHECK(config);
   return new CrxUpdateService(config);
 }