components/update_client/update_checker.cc

// Copyright 2014 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 "components/update_client/update_checker.h"

#include <stddef.h>

#include <memory>
#include <string>
#include <vector>

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/location.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/strings/stringprintf.h"
#include "base/threading/thread_checker.h"
#include "base/threading/thread_task_runner_handle.h"
#include "components/update_client/configurator.h"
#include "components/update_client/crx_update_item.h"
#include "components/update_client/persisted_data.h"
#include "components/update_client/request_sender.h"
#include "components/update_client/utils.h"
#include "url/gurl.h"

namespace update_client {

namespace {

// Returns a sanitized version of the brand or an empty string otherwise.
std::string SanitizeBrand(const std::string& brand) {
  return IsValidBrand(brand) ? brand : std::string("");
}

// Returns a sanitized version of the |ap| or an empty string otherwise.
std::string SanitizeAp(const std::string& ap) {
  return IsValidAp(ap) ? ap : std::string();
}

// Returns true if at least one item requires network encryption.
bool IsEncryptionRequired(const std::vector<CrxUpdateItem*>& items) {
  for (const auto& item : items) {
    if (item->component.requires_network_encryption)
      return true;
  }
  return false;
}

// Builds an update check request for |components|. |additional_attributes| is
// serialized as part of the <request> element of the request to customize it
// with data that is not platform or component specific. For each |item|, a
// corresponding <app> element is created and inserted as a child node of
// the <request>.
//
// An app element looks like this:
//    <app appid="hnimpnehoodheedghdeeijklkeaacbdc"
//         version="0.1.2.3" installsource="ondemand">
//      <updatecheck />
//      <packages>
//        <package fp="abcd" />
//      </packages>
//    </app>
std::string BuildUpdateCheckRequest(const Configurator& config,
                                    const std::vector<CrxUpdateItem*>& items,
                                    PersistedData* metadata,
                                    const std::string& additional_attributes) {
  const std::string brand(SanitizeBrand(config.GetBrand()));
  std::string app_elements;
  for (size_t i = 0; i != items.size(); ++i) {
    const CrxUpdateItem* item = items[i];
    const std::string ap(SanitizeAp(item->component.ap));
    std::string app("<app ");
    base::StringAppendF(&app, "appid=\"%s\" version=\"%s\"", item->id.c_str(),
                        item->component.version.GetString().c_str());
    if (!brand.empty())
      base::StringAppendF(&app, " brand=\"%s\"", brand.c_str());
    if (item->on_demand)
      base::StringAppendF(&app, " installsource=\"ondemand\"");
    if (!ap.empty())
      base::StringAppendF(&app, " ap=\"%s\"", ap.c_str());
    base::StringAppendF(&app, ">");
    base::StringAppendF(&app, "<updatecheck />");
    base::StringAppendF(&app, "<ping rd=\"%d\" ping_freshness=\"%s\" />",
                        metadata->GetDateLastRollCall(item->id),
                        metadata->GetPingFreshness(item->id).c_str());
    if (!item->component.fingerprint.empty()) {
      base::StringAppendF(&app,
                          "<packages>"
                          "<package fp=\"%s\"/>"
                          "</packages>",
                          item->component.fingerprint.c_str());
    }
    base::StringAppendF(&app, "</app>");
    app_elements.append(app);
    VLOG(1) << "Appending to update request: " << app;
  }

  return BuildProtocolRequest(
      config.GetBrowserVersion().GetString(), config.GetChannel(),
      config.GetLang(), config.GetOSLongName(), config.GetDownloadPreference(),
      app_elements, additional_attributes);
}

class UpdateCheckerImpl : public UpdateChecker {
 public:
  UpdateCheckerImpl(const scoped_refptr<Configurator>& config,
                    PersistedData* metadata);
  ~UpdateCheckerImpl() override;

  // Overrides for UpdateChecker.
  bool CheckForUpdates(
      const std::vector<CrxUpdateItem*>& items_to_check,
      const std::string& additional_attributes,
      const UpdateCheckCallback& update_check_callback) override;

 private:
  void OnRequestSenderComplete(
      std::unique_ptr<std::vector<std::string>> ids_checked,
      int error,
      const std::string& response,
      int retry_after_sec);
  base::ThreadChecker thread_checker_;

  const scoped_refptr<Configurator> config_;
  PersistedData* metadata_;
  UpdateCheckCallback update_check_callback_;
  std::unique_ptr<RequestSender> request_sender_;

  DISALLOW_COPY_AND_ASSIGN(UpdateCheckerImpl);
};

UpdateCheckerImpl::UpdateCheckerImpl(const scoped_refptr<Configurator>& config,
                                     PersistedData* metadata)
    : config_(config), metadata_(metadata) {}

UpdateCheckerImpl::~UpdateCheckerImpl() {
  DCHECK(thread_checker_.CalledOnValidThread());
}

bool UpdateCheckerImpl::CheckForUpdates(
    const std::vector<CrxUpdateItem*>& items_to_check,
    const std::string& additional_attributes,
    const UpdateCheckCallback& update_check_callback) {
  DCHECK(thread_checker_.CalledOnValidThread());

  if (request_sender_.get()) {
    NOTREACHED();
    return false;  // Another update check is in progress.
  }

  update_check_callback_ = update_check_callback;

  auto urls(config_->UpdateUrl());
  if (IsEncryptionRequired(items_to_check))
    RemoveUnsecureUrls(&urls);

  std::unique_ptr<std::vector<std::string>> ids_checked(
      new std::vector<std::string>());
  for (auto crx : items_to_check)
    ids_checked->push_back(crx->id);
  request_sender_.reset(new RequestSender(config_));
  request_sender_->Send(
      config_->UseCupSigning(),
      BuildUpdateCheckRequest(*config_, items_to_check, metadata_,
                              additional_attributes),
      urls, base::Bind(&UpdateCheckerImpl::OnRequestSenderComplete,
                       base::Unretained(this), base::Passed(&ids_checked)));
  return true;
}

void UpdateCheckerImpl::OnRequestSenderComplete(
    std::unique_ptr<std::vector<std::string>> ids_checked,
    int error,
    const std::string& response,
    int retry_after_sec) {
  DCHECK(thread_checker_.CalledOnValidThread());

  if (!error) {
    UpdateResponse update_response;
    if (update_response.Parse(response)) {
      int daynum = update_response.results().daystart_elapsed_days;
      if (daynum != UpdateResponse::kNoDaystart)
        metadata_->SetDateLastRollCall(*ids_checked, daynum);
      base::ThreadTaskRunnerHandle::Get()->PostTask(
          FROM_HERE, base::Bind(update_check_callback_, error,
                                update_response.results(), retry_after_sec));
      return;
    }

    error = -1;
    VLOG(1) << "Parse failed " << update_response.errors();
  }

  base::ThreadTaskRunnerHandle::Get()->PostTask(
      FROM_HERE, base::Bind(update_check_callback_, error,
                            UpdateResponse::Results(), retry_after_sec));
}

}  // namespace

std::unique_ptr<UpdateChecker> UpdateChecker::Create(
    const scoped_refptr<Configurator>& config,
    PersistedData* persistent) {
  return std::unique_ptr<UpdateChecker>(
      new UpdateCheckerImpl(config, persistent));
}

}  // namespace update_client