chrome/browser/extensions/updater/manifest_fetch_data.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/extensions/updater/manifest_fetch_data.h"

#include <vector>

#include "base/logging.h"
#include "base/metrics/histogram.h"
#include "base/string_number_conversions.h"
#include "base/string_util.h"
#include "chrome/browser/google/google_util.h"
#include "net/base/escape.h"

namespace {

// Maximum length of an extension manifest update check url, since it is a GET
// request. We want to stay under 2K because of proxies, etc.
const int kExtensionsManifestMaxURLSize = 2000;

}  // namespace

namespace extensions {

ManifestFetchData::ManifestFetchData(const GURL& update_url)
    : base_url_(update_url),
      full_url_(update_url) {
}

ManifestFetchData::~ManifestFetchData() {}

// The format for request parameters in update checks is:
//
//   ?x=EXT1_INFO&x=EXT2_INFO
//
// where EXT1_INFO and EXT2_INFO are url-encoded strings of the form:
//
//   id=EXTENSION_ID&v=VERSION&uc
//
// Additionally, we may include the parameter ping=PING_DATA where PING_DATA
// looks like r=DAYS or a=DAYS for extensions in the Chrome extensions gallery.
// ('r' refers to 'roll call' ie installation, and 'a' refers to 'active').
// These values will each be present at most once every 24 hours, and indicate
// the number of days since the last time it was present in an update check.
//
// So for two extensions like:
//   Extension 1- id:aaaa version:1.1
//   Extension 2- id:bbbb version:2.0
//
// the full update url would be:
//   http://somehost/path?x=id%3Daaaa%26v%3D1.1%26uc&x=id%3Dbbbb%26v%3D2.0%26uc
//
// (Note that '=' is %3D and '&' is %26 when urlencoded.)
bool ManifestFetchData::AddExtension(std::string id, std::string version,
                                     const PingData* ping_data,
                                     const std::string& update_url_data,
                                     const std::string& install_source) {
  if (extension_ids_.find(id) != extension_ids_.end()) {
    NOTREACHED() << "Duplicate extension id " << id;
    return false;
  }

  // Compute the string we'd append onto the full_url_, and see if it fits.
  std::vector<std::string> parts;
  parts.push_back("id=" + id);
  parts.push_back("v=" + version);
  if (!install_source.empty())
    parts.push_back("installsource=" + install_source);
  parts.push_back("uc");

  if (!update_url_data.empty()) {
    // Make sure the update_url_data string is escaped before using it so that
    // there is no chance of overriding the id or v other parameter value
    // we place into the x= value.
    parts.push_back("ap=" + net::EscapeQueryParamValue(update_url_data, true));
  }

  // Append brand code, rollcall and active ping parameters.
  if (base_url_.DomainIs("google.com")) {
#if defined(GOOGLE_CHROME_BUILD)
    std::string brand;
    google_util::GetBrand(&brand);
    if (!brand.empty() && !google_util::IsOrganic(brand))
      parts.push_back("brand=" + brand);
#endif

    std::string ping_value;
    pings_[id] = PingData(0, 0);

    if (ping_data) {
      if (ping_data->rollcall_days == kNeverPinged ||
          ping_data->rollcall_days > 0) {
        ping_value += "r=" + base::IntToString(ping_data->rollcall_days);
        pings_[id].rollcall_days = ping_data->rollcall_days;
      }
      if (ping_data->active_days == kNeverPinged ||
          ping_data->active_days > 0) {
        if (!ping_value.empty())
          ping_value += "&";
        ping_value += "a=" + base::IntToString(ping_data->active_days);
        pings_[id].active_days = ping_data->active_days;
      }
    }
    if (!ping_value.empty())
      parts.push_back("ping=" + net::EscapeQueryParamValue(ping_value, true));
  }

  std::string extra = full_url_.has_query() ? "&" : "?";
  extra += "x=" + net::EscapeQueryParamValue(JoinString(parts, '&'), true);

  // Check against our max url size, exempting the first extension added.
  int new_size = full_url_.possibly_invalid_spec().size() + extra.size();
  if (!extension_ids_.empty() && new_size > kExtensionsManifestMaxURLSize) {
    UMA_HISTOGRAM_PERCENTAGE("Extensions.UpdateCheckHitUrlSizeLimit", 1);
    return false;
  }
  UMA_HISTOGRAM_PERCENTAGE("Extensions.UpdateCheckHitUrlSizeLimit", 0);

  // We have room so go ahead and add the extension.
  extension_ids_.insert(id);
  full_url_ = GURL(full_url_.possibly_invalid_spec() + extra);
  return true;
}

bool ManifestFetchData::Includes(const std::string& extension_id) const {
  return extension_ids_.find(extension_id) != extension_ids_.end();
}

bool ManifestFetchData::DidPing(std::string extension_id, PingType type) const {
  std::map<std::string, PingData>::const_iterator i = pings_.find(extension_id);
  if (i == pings_.end())
    return false;
  int value = 0;
  if (type == ROLLCALL)
    value = i->second.rollcall_days;
  else if (type == ACTIVE)
    value = i->second.active_days;
  else
    NOTREACHED();
  return value == kNeverPinged || value > 0;
}

}  // namespace extensions