cms/drupal/modules/update/update.compare.inc
changeset 541 e756a8c72c3d
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cms/drupal/modules/update/update.compare.inc	Fri Sep 08 12:04:06 2017 +0200
@@ -0,0 +1,838 @@
+<?php
+
+/**
+ * @file
+ * Code required only when comparing available updates to existing data.
+ */
+
+/**
+ * Fetches an array of installed and enabled projects.
+ *
+ * This is only responsible for generating an array of projects (taking into
+ * account projects that include more than one module or theme). Other
+ * information like the specific version and install type (official release,
+ * dev snapshot, etc) is handled later in update_process_project_info() since
+ * that logic is only required when preparing the status report, not for
+ * fetching the available release data.
+ *
+ * This array is fairly expensive to construct, since it involves a lot of disk
+ * I/O, so we cache the results into the {cache_update} table using the
+ * 'update_project_projects' cache ID. However, since this is not the data about
+ * available updates fetched from the network, it is acceptable to invalidate it
+ * somewhat quickly. If we keep this data for very long, site administrators are
+ * more likely to see incorrect results if they upgrade to a newer version of a
+ * module or theme but do not visit certain pages that automatically clear this
+ * cache.
+ *
+ * @return
+ *   An associative array of currently enabled projects keyed by the
+ *   machine-readable project short name. Each project contains:
+ *   - name: The machine-readable project short name.
+ *   - info: An array with values from the main .info file for this project.
+ *     - name: The human-readable name of the project.
+ *     - package: The package that the project is grouped under.
+ *     - version: The version of the project.
+ *     - project: The Drupal.org project name.
+ *     - datestamp: The date stamp of the project's main .info file.
+ *     - _info_file_ctime: The maximum file change time for all of the .info
+ *       files included in this project.
+ *   - datestamp: The date stamp when the project was released, if known.
+ *   - includes: An associative array containing all projects included with this
+ *     project, keyed by the machine-readable short name with the human-readable
+ *     name as value.
+ *   - project_type: The type of project. Allowed values are 'module' and
+ *     'theme'.
+ *   - project_status: This indicates if the project is enabled and will always
+ *     be TRUE, as the function only returns enabled projects.
+ *   - sub_themes: If the project is a theme it contains an associative array of
+ *     all sub-themes.
+ *   - base_themes: If the project is a theme it contains an associative array
+ *     of all base-themes.
+ *
+ * @see update_process_project_info()
+ * @see update_calculate_project_data()
+ * @see update_project_cache()
+ */
+function update_get_projects() {
+  $projects = &drupal_static(__FUNCTION__, array());
+  if (empty($projects)) {
+    // Retrieve the projects from cache, if present.
+    $projects = update_project_cache('update_project_projects');
+    if (empty($projects)) {
+      // Still empty, so we have to rebuild the cache.
+      $module_data = system_rebuild_module_data();
+      $theme_data = system_rebuild_theme_data();
+      _update_process_info_list($projects, $module_data, 'module', TRUE);
+      _update_process_info_list($projects, $theme_data, 'theme', TRUE);
+      if (variable_get('update_check_disabled', FALSE)) {
+        _update_process_info_list($projects, $module_data, 'module', FALSE);
+        _update_process_info_list($projects, $theme_data, 'theme', FALSE);
+      }
+      // Allow other modules to alter projects before fetching and comparing.
+      drupal_alter('update_projects', $projects);
+      // Cache the site's project data for at most 1 hour.
+      _update_cache_set('update_project_projects', $projects, REQUEST_TIME + 3600);
+    }
+  }
+  return $projects;
+}
+
+/**
+ * Populates an array of project data.
+ *
+ * This iterates over a list of the installed modules or themes and groups them
+ * by project and status. A few parts of this function assume that enabled
+ * modules and themes are always processed first, and if disabled modules or
+ * themes are being processed (there is a setting to control if disabled code
+ * should be included or not in the 'Available updates' report), those are only
+ * processed after $projects has been populated with information about the
+ * enabled code. Modules and themes set as hidden are always ignored. This
+ * function also records the latest change time on the .info files for each
+ * module or theme, which is important data which is used when deciding if the
+ * cached available update data should be invalidated.
+ *
+ * @param $projects
+ *   Reference to the array of project data of what's installed on this site.
+ * @param $list
+ *   Array of data to process to add the relevant info to the $projects array.
+ * @param $project_type
+ *   The kind of data in the list. Can be 'module' or 'theme'.
+ * @param $status
+ *   Boolean that controls what status (enabled or disabled) to process out of
+ *   the $list and add to the $projects array.
+ *
+ * @see update_get_projects()
+ */
+function _update_process_info_list(&$projects, $list, $project_type, $status) {
+  $admin_theme = variable_get('admin_theme', 'seven');
+  foreach ($list as $file) {
+    // The admin theme is a special case. It should always be considered enabled
+    // for the purposes of update checking.
+    if ($file->name === $admin_theme) {
+      $file->status = TRUE;
+    }
+    // A disabled base theme of an enabled sub-theme still has all of its code
+    // run by the sub-theme, so we include it in our "enabled" projects list.
+    if ($status && !$file->status && !empty($file->sub_themes)) {
+      foreach ($file->sub_themes as $key => $name) {
+        // Build a list of enabled sub-themes.
+        if ($list[$key]->status) {
+          $file->enabled_sub_themes[$key] = $name;
+        }
+      }
+      // If there are no enabled subthemes, we should ignore this base theme
+      // for the enabled case. If the site is trying to display disabled
+      // themes, we'll catch it then.
+      if (empty($file->enabled_sub_themes)) {
+        continue;
+      }
+    }
+    // Otherwise, just add projects of the proper status to our list.
+    elseif ($file->status != $status) {
+      continue;
+    }
+
+    // Skip if the .info file is broken.
+    if (empty($file->info)) {
+      continue;
+    }
+
+    // Skip if it's a hidden module or theme.
+    if (!empty($file->info['hidden'])) {
+      continue;
+    }
+
+    // If the .info doesn't define the 'project', try to figure it out.
+    if (!isset($file->info['project'])) {
+      $file->info['project'] = update_get_project_name($file);
+    }
+
+    // If we still don't know the 'project', give up.
+    if (empty($file->info['project'])) {
+      continue;
+    }
+
+    // If we don't already know it, grab the change time on the .info file
+    // itself. Note: we need to use the ctime, not the mtime (modification
+    // time) since many (all?) tar implementations will go out of their way to
+    // set the mtime on the files it creates to the timestamps recorded in the
+    // tarball. We want to see the last time the file was changed on disk,
+    // which is left alone by tar and correctly set to the time the .info file
+    // was unpacked.
+    if (!isset($file->info['_info_file_ctime'])) {
+      $info_filename = dirname($file->uri) . '/' . $file->name . '.info';
+      $file->info['_info_file_ctime'] = filectime($info_filename);
+    }
+
+    if (!isset($file->info['datestamp'])) {
+      $file->info['datestamp'] = 0;
+    }
+
+    $project_name = $file->info['project'];
+
+    // Figure out what project type we're going to use to display this module
+    // or theme. If the project name is 'drupal', we don't want it to show up
+    // under the usual "Modules" section, we put it at a special "Drupal Core"
+    // section at the top of the report.
+    if ($project_name == 'drupal') {
+      $project_display_type = 'core';
+    }
+    else {
+      $project_display_type = $project_type;
+    }
+    if (empty($status) && empty($file->enabled_sub_themes)) {
+      // If we're processing disabled modules or themes, append a suffix.
+      // However, we don't do this to a a base theme with enabled
+      // subthemes, since we treat that case as if it is enabled.
+      $project_display_type .= '-disabled';
+    }
+    // Add a list of sub-themes that "depend on" the project and a list of base
+    // themes that are "required by" the project.
+    if ($project_name == 'drupal') {
+      // Drupal core is always required, so this extra info would be noise.
+      $sub_themes = array();
+      $base_themes = array();
+    }
+    else {
+      // Add list of enabled sub-themes.
+      $sub_themes = !empty($file->enabled_sub_themes) ? $file->enabled_sub_themes : array();
+      // Add list of base themes.
+      $base_themes = !empty($file->base_themes) ? $file->base_themes : array();
+    }
+    if (!isset($projects[$project_name])) {
+      // Only process this if we haven't done this project, since a single
+      // project can have multiple modules or themes.
+      $projects[$project_name] = array(
+        'name' => $project_name,
+        // Only save attributes from the .info file we care about so we do not
+        // bloat our RAM usage needlessly.
+        'info' => update_filter_project_info($file->info),
+        'datestamp' => $file->info['datestamp'],
+        'includes' => array($file->name => $file->info['name']),
+        'project_type' => $project_display_type,
+        'project_status' => $status,
+        'sub_themes' => $sub_themes,
+        'base_themes' => $base_themes,
+      );
+    }
+    elseif ($projects[$project_name]['project_type'] == $project_display_type) {
+      // Only add the file we're processing to the 'includes' array for this
+      // project if it is of the same type and status (which is encoded in the
+      // $project_display_type). This prevents listing all the disabled
+      // modules included with an enabled project if we happen to be checking
+      // for disabled modules, too.
+      $projects[$project_name]['includes'][$file->name] = $file->info['name'];
+      $projects[$project_name]['info']['_info_file_ctime'] = max($projects[$project_name]['info']['_info_file_ctime'], $file->info['_info_file_ctime']);
+      $projects[$project_name]['datestamp'] = max($projects[$project_name]['datestamp'], $file->info['datestamp']);
+      if (!empty($sub_themes)) {
+        $projects[$project_name]['sub_themes'] += $sub_themes;
+      }
+      if (!empty($base_themes)) {
+        $projects[$project_name]['base_themes'] += $base_themes;
+      }
+    }
+    elseif (empty($status)) {
+      // If we have a project_name that matches, but the project_display_type
+      // does not, it means we're processing a disabled module or theme that
+      // belongs to a project that has some enabled code. In this case, we add
+      // the disabled thing into a separate array for separate display.
+      $projects[$project_name]['disabled'][$file->name] = $file->info['name'];
+    }
+  }
+}
+
+/**
+ * Determines what project a given file object belongs to.
+ *
+ * @param $file
+ *   A file object as returned by system_get_files_database().
+ *
+ * @return
+ *   The canonical project short name.
+ *
+ * @see system_get_files_database()
+ */
+function update_get_project_name($file) {
+  $project_name = '';
+  if (isset($file->info['project'])) {
+    $project_name = $file->info['project'];
+  }
+  elseif (isset($file->info['package']) && (strpos($file->info['package'], 'Core') === 0)) {
+    $project_name = 'drupal';
+  }
+  return $project_name;
+}
+
+/**
+ * Determines version and type information for currently installed projects.
+ *
+ * Processes the list of projects on the system to figure out the currently
+ * installed versions, and other information that is required before we can
+ * compare against the available releases to produce the status report.
+ *
+ * @param $projects
+ *   Array of project information from update_get_projects().
+ */
+function update_process_project_info(&$projects) {
+  foreach ($projects as $key => $project) {
+    // Assume an official release until we see otherwise.
+    $install_type = 'official';
+
+    $info = $project['info'];
+
+    if (isset($info['version'])) {
+      // Check for development snapshots
+      if (preg_match('@(dev|HEAD)@', $info['version'])) {
+        $install_type = 'dev';
+      }
+
+      // Figure out what the currently installed major version is. We need
+      // to handle both contribution (e.g. "5.x-1.3", major = 1) and core
+      // (e.g. "5.1", major = 5) version strings.
+      $matches = array();
+      if (preg_match('/^(\d+\.x-)?(\d+)\..*$/', $info['version'], $matches)) {
+        $info['major'] = $matches[2];
+      }
+      elseif (!isset($info['major'])) {
+        // This would only happen for version strings that don't follow the
+        // drupal.org convention. We let contribs define "major" in their
+        // .info in this case, and only if that's missing would we hit this.
+        $info['major'] = -1;
+      }
+    }
+    else {
+      // No version info available at all.
+      $install_type = 'unknown';
+      $info['version'] = t('Unknown');
+      $info['major'] = -1;
+    }
+
+    // Finally, save the results we care about into the $projects array.
+    $projects[$key]['existing_version'] = $info['version'];
+    $projects[$key]['existing_major'] = $info['major'];
+    $projects[$key]['install_type'] = $install_type;
+  }
+}
+
+/**
+ * Calculates the current update status of all projects on the site.
+ *
+ * The results of this function are expensive to compute, especially on sites
+ * with lots of modules or themes, since it involves a lot of comparisons and
+ * other operations. Therefore, we cache the results into the {cache_update}
+ * table using the 'update_project_data' cache ID. However, since this is not
+ * the data about available updates fetched from the network, it is ok to
+ * invalidate it somewhat quickly. If we keep this data for very long, site
+ * administrators are more likely to see incorrect results if they upgrade to a
+ * newer version of a module or theme but do not visit certain pages that
+ * automatically clear this cache.
+ *
+ * @param array $available
+ *   Data about available project releases.
+ *
+ * @return
+ *   An array of installed projects with current update status information.
+ *
+ * @see update_get_available()
+ * @see update_get_projects()
+ * @see update_process_project_info()
+ * @see update_project_cache()
+ */
+function update_calculate_project_data($available) {
+  // Retrieve the projects from cache, if present.
+  $projects = update_project_cache('update_project_data');
+  // If $projects is empty, then the cache must be rebuilt.
+  // Otherwise, return the cached data and skip the rest of the function.
+  if (!empty($projects)) {
+    return $projects;
+  }
+  $projects = update_get_projects();
+  update_process_project_info($projects);
+  foreach ($projects as $project => $project_info) {
+    if (isset($available[$project])) {
+      update_calculate_project_update_status($project, $projects[$project], $available[$project]);
+    }
+    else {
+      $projects[$project]['status'] = UPDATE_UNKNOWN;
+      $projects[$project]['reason'] = t('No available releases found');
+    }
+  }
+  // Give other modules a chance to alter the status (for example, to allow a
+  // contrib module to provide fine-grained settings to ignore specific
+  // projects or releases).
+  drupal_alter('update_status', $projects);
+
+  // Cache the site's update status for at most 1 hour.
+  _update_cache_set('update_project_data', $projects, REQUEST_TIME + 3600);
+  return $projects;
+}
+
+/**
+ * Calculates the current update status of a specific project.
+ *
+ * This function is the heart of the update status feature. For each project it
+ * is invoked with, it first checks if the project has been flagged with a
+ * special status like "unsupported" or "insecure", or if the project node
+ * itself has been unpublished. In any of those cases, the project is marked
+ * with an error and the next project is considered.
+ *
+ * If the project itself is valid, the function decides what major release
+ * series to consider. The project defines what the currently supported major
+ * versions are for each version of core, so the first step is to make sure the
+ * current version is still supported. If so, that's the target version. If the
+ * current version is unsupported, the project maintainer's recommended major
+ * version is used. There's also a check to make sure that this function never
+ * recommends an earlier release than the currently installed major version.
+ *
+ * Given a target major version, the available releases are scanned looking for
+ * the specific release to recommend (avoiding beta releases and development
+ * snapshots if possible). For the target major version, the highest patch level
+ * is found. If there is a release at that patch level with no extra ("beta",
+ * etc.), then the release at that patch level with the most recent release date
+ * is recommended. If every release at that patch level has extra (only betas),
+ * then the latest release from the previous patch level is recommended. For
+ * example:
+ *
+ * - 1.6-bugfix <-- recommended version because 1.6 already exists.
+ * - 1.6
+ *
+ * or
+ *
+ * - 1.6-beta
+ * - 1.5 <-- recommended version because no 1.6 exists.
+ * - 1.4
+ *
+ * Also, the latest release from the same major version is looked for, even beta
+ * releases, to display to the user as the "Latest version" option.
+ * Additionally, the latest official release from any higher major versions that
+ * have been released is searched for to provide a set of "Also available"
+ * options.
+ *
+ * Finally, and most importantly, the release history continues to be scanned
+ * until the currently installed release is reached, searching for anything
+ * marked as a security update. If any security updates have been found between
+ * the recommended release and the installed version, all of the releases that
+ * included a security fix are recorded so that the site administrator can be
+ * warned their site is insecure, and links pointing to the release notes for
+ * each security update can be included (which, in turn, will link to the
+ * official security announcements for each vulnerability).
+ *
+ * This function relies on the fact that the .xml release history data comes
+ * sorted based on major version and patch level, then finally by release date
+ * if there are multiple releases such as betas from the same major.patch
+ * version (e.g., 5.x-1.5-beta1, 5.x-1.5-beta2, and 5.x-1.5). Development
+ * snapshots for a given major version are always listed last.
+ *
+ * @param $unused
+ *   Input is not being used, but remains in function for API compatibility
+ *   reasons.
+ * @param $project_data
+ *   An array containing information about a specific project.
+ * @param $available
+ *   Data about available project releases of a specific project.
+ */
+function update_calculate_project_update_status($unused, &$project_data, $available) {
+  foreach (array('title', 'link') as $attribute) {
+    if (!isset($project_data[$attribute]) && isset($available[$attribute])) {
+      $project_data[$attribute] = $available[$attribute];
+    }
+  }
+
+  // If the project status is marked as something bad, there's nothing else
+  // to consider.
+  if (isset($available['project_status'])) {
+    switch ($available['project_status']) {
+      case 'insecure':
+        $project_data['status'] = UPDATE_NOT_SECURE;
+        if (empty($project_data['extra'])) {
+          $project_data['extra'] = array();
+        }
+        $project_data['extra'][] = array(
+          'class' => array('project-not-secure'),
+          'label' => t('Project not secure'),
+          'data' => t('This project has been labeled insecure by the Drupal security team, and is no longer available for download. Immediately disabling everything included by this project is strongly recommended!'),
+        );
+        break;
+      case 'unpublished':
+      case 'revoked':
+        $project_data['status'] = UPDATE_REVOKED;
+        if (empty($project_data['extra'])) {
+          $project_data['extra'] = array();
+        }
+        $project_data['extra'][] = array(
+          'class' => array('project-revoked'),
+          'label' => t('Project revoked'),
+          'data' => t('This project has been revoked, and is no longer available for download. Disabling everything included by this project is strongly recommended!'),
+        );
+        break;
+      case 'unsupported':
+        $project_data['status'] = UPDATE_NOT_SUPPORTED;
+        if (empty($project_data['extra'])) {
+          $project_data['extra'] = array();
+        }
+        $project_data['extra'][] = array(
+          'class' => array('project-not-supported'),
+          'label' => t('Project not supported'),
+          'data' => t('This project is no longer supported, and is no longer available for download. Disabling everything included by this project is strongly recommended!'),
+        );
+        break;
+      case 'not-fetched':
+        $project_data['status'] = UPDATE_NOT_FETCHED;
+        $project_data['reason'] = t('Failed to get available update data.');
+        break;
+
+      default:
+        // Assume anything else (e.g. 'published') is valid and we should
+        // perform the rest of the logic in this function.
+        break;
+    }
+  }
+
+  if (!empty($project_data['status'])) {
+    // We already know the status for this project, so there's nothing else to
+    // compute. Record the project status into $project_data and we're done.
+    $project_data['project_status'] = $available['project_status'];
+    return;
+  }
+
+  // Figure out the target major version.
+  $existing_major = $project_data['existing_major'];
+  $supported_majors = array();
+  if (isset($available['supported_majors'])) {
+    $supported_majors = explode(',', $available['supported_majors']);
+  }
+  elseif (isset($available['default_major'])) {
+    // Older release history XML file without supported or recommended.
+    $supported_majors[] = $available['default_major'];
+  }
+
+  if (in_array($existing_major, $supported_majors)) {
+    // Still supported, stay at the current major version.
+    $target_major = $existing_major;
+  }
+  elseif (isset($available['recommended_major'])) {
+    // Since 'recommended_major' is defined, we know this is the new XML
+    // format. Therefore, we know the current release is unsupported since
+    // its major version was not in the 'supported_majors' list. We should
+    // find the best release from the recommended major version.
+    $target_major = $available['recommended_major'];
+    $project_data['status'] = UPDATE_NOT_SUPPORTED;
+  }
+  elseif (isset($available['default_major'])) {
+    // Older release history XML file without recommended, so recommend
+    // the currently defined "default_major" version.
+    $target_major = $available['default_major'];
+  }
+  else {
+    // Malformed XML file? Stick with the current version.
+    $target_major = $existing_major;
+  }
+
+  // Make sure we never tell the admin to downgrade. If we recommended an
+  // earlier version than the one they're running, they'd face an
+  // impossible data migration problem, since Drupal never supports a DB
+  // downgrade path. In the unfortunate case that what they're running is
+  // unsupported, and there's nothing newer for them to upgrade to, we
+  // can't print out a "Recommended version", but just have to tell them
+  // what they have is unsupported and let them figure it out.
+  $target_major = max($existing_major, $target_major);
+
+  $release_patch_changed = '';
+  $patch = '';
+
+  // If the project is marked as UPDATE_FETCH_PENDING, it means that the
+  // data we currently have (if any) is stale, and we've got a task queued
+  // up to (re)fetch the data. In that case, we mark it as such, merge in
+  // whatever data we have (e.g. project title and link), and move on.
+  if (!empty($available['fetch_status']) && $available['fetch_status'] == UPDATE_FETCH_PENDING) {
+    $project_data['status'] = UPDATE_FETCH_PENDING;
+    $project_data['reason'] = t('No available update data');
+    $project_data['fetch_status'] = $available['fetch_status'];
+    return;
+  }
+
+  // Defend ourselves from XML history files that contain no releases.
+  if (empty($available['releases'])) {
+    $project_data['status'] = UPDATE_UNKNOWN;
+    $project_data['reason'] = t('No available releases found');
+    return;
+  }
+  foreach ($available['releases'] as $version => $release) {
+    // First, if this is the existing release, check a few conditions.
+    if ($project_data['existing_version'] === $version) {
+      if (isset($release['terms']['Release type']) &&
+          in_array('Insecure', $release['terms']['Release type'])) {
+        $project_data['status'] = UPDATE_NOT_SECURE;
+      }
+      elseif ($release['status'] == 'unpublished') {
+        $project_data['status'] = UPDATE_REVOKED;
+        if (empty($project_data['extra'])) {
+          $project_data['extra'] = array();
+        }
+        $project_data['extra'][] = array(
+          'class' => array('release-revoked'),
+          'label' => t('Release revoked'),
+          'data' => t('Your currently installed release has been revoked, and is no longer available for download. Disabling everything included in this release or upgrading is strongly recommended!'),
+        );
+      }
+      elseif (isset($release['terms']['Release type']) &&
+              in_array('Unsupported', $release['terms']['Release type'])) {
+        $project_data['status'] = UPDATE_NOT_SUPPORTED;
+        if (empty($project_data['extra'])) {
+          $project_data['extra'] = array();
+        }
+        $project_data['extra'][] = array(
+          'class' => array('release-not-supported'),
+          'label' => t('Release not supported'),
+          'data' => t('Your currently installed release is now unsupported, and is no longer available for download. Disabling everything included in this release or upgrading is strongly recommended!'),
+        );
+      }
+    }
+
+    // Otherwise, ignore unpublished, insecure, or unsupported releases.
+    if ($release['status'] == 'unpublished' ||
+        (isset($release['terms']['Release type']) &&
+         (in_array('Insecure', $release['terms']['Release type']) ||
+          in_array('Unsupported', $release['terms']['Release type'])))) {
+      continue;
+    }
+
+    // See if this is a higher major version than our target and yet still
+    // supported. If so, record it as an "Also available" release.
+    // Note: some projects have a HEAD release from CVS days, which could
+    // be one of those being compared. They would not have version_major
+    // set, so we must call isset first.
+    if (isset($release['version_major']) && $release['version_major'] > $target_major) {
+      if (in_array($release['version_major'], $supported_majors)) {
+        if (!isset($project_data['also'])) {
+          $project_data['also'] = array();
+        }
+        if (!isset($project_data['also'][$release['version_major']])) {
+          $project_data['also'][$release['version_major']] = $version;
+          $project_data['releases'][$version] = $release;
+        }
+      }
+      // Otherwise, this release can't matter to us, since it's neither
+      // from the release series we're currently using nor the recommended
+      // release. We don't even care about security updates for this
+      // branch, since if a project maintainer puts out a security release
+      // at a higher major version and not at the lower major version,
+      // they must remove the lower version from the supported major
+      // versions at the same time, in which case we won't hit this code.
+      continue;
+    }
+
+    // Look for the 'latest version' if we haven't found it yet. Latest is
+    // defined as the most recent version for the target major version.
+    if (!isset($project_data['latest_version'])
+        && $release['version_major'] == $target_major) {
+      $project_data['latest_version'] = $version;
+      $project_data['releases'][$version] = $release;
+    }
+
+    // Look for the development snapshot release for this branch.
+    if (!isset($project_data['dev_version'])
+        && $release['version_major'] == $target_major
+        && isset($release['version_extra'])
+        && $release['version_extra'] == 'dev') {
+      $project_data['dev_version'] = $version;
+      $project_data['releases'][$version] = $release;
+    }
+
+    // Look for the 'recommended' version if we haven't found it yet (see
+    // phpdoc at the top of this function for the definition).
+    if (!isset($project_data['recommended'])
+        && $release['version_major'] == $target_major
+        && isset($release['version_patch'])) {
+      if ($patch != $release['version_patch']) {
+        $patch = $release['version_patch'];
+        $release_patch_changed = $release;
+      }
+      if (empty($release['version_extra']) && $patch == $release['version_patch']) {
+        $project_data['recommended'] = $release_patch_changed['version'];
+        $project_data['releases'][$release_patch_changed['version']] = $release_patch_changed;
+      }
+    }
+
+    // Stop searching once we hit the currently installed version.
+    if ($project_data['existing_version'] === $version) {
+      break;
+    }
+
+    // If we're running a dev snapshot and have a timestamp, stop
+    // searching for security updates once we hit an official release
+    // older than what we've got. Allow 100 seconds of leeway to handle
+    // differences between the datestamp in the .info file and the
+    // timestamp of the tarball itself (which are usually off by 1 or 2
+    // seconds) so that we don't flag that as a new release.
+    if ($project_data['install_type'] == 'dev') {
+      if (empty($project_data['datestamp'])) {
+        // We don't have current timestamp info, so we can't know.
+        continue;
+      }
+      elseif (isset($release['date']) && ($project_data['datestamp'] + 100 > $release['date'])) {
+        // We're newer than this, so we can skip it.
+        continue;
+      }
+    }
+
+    // See if this release is a security update.
+    if (isset($release['terms']['Release type'])
+        && in_array('Security update', $release['terms']['Release type'])) {
+      $project_data['security updates'][] = $release;
+    }
+  }
+
+  // If we were unable to find a recommended version, then make the latest
+  // version the recommended version if possible.
+  if (!isset($project_data['recommended']) && isset($project_data['latest_version'])) {
+    $project_data['recommended'] = $project_data['latest_version'];
+  }
+
+  //
+  // Check to see if we need an update or not.
+  //
+
+  if (!empty($project_data['security updates'])) {
+    // If we found security updates, that always trumps any other status.
+    $project_data['status'] = UPDATE_NOT_SECURE;
+  }
+
+  if (isset($project_data['status'])) {
+    // If we already know the status, we're done.
+    return;
+  }
+
+  // If we don't know what to recommend, there's nothing we can report.
+  // Bail out early.
+  if (!isset($project_data['recommended'])) {
+    $project_data['status'] = UPDATE_UNKNOWN;
+    $project_data['reason'] = t('No available releases found');
+    return;
+  }
+
+  // If we're running a dev snapshot, compare the date of the dev snapshot
+  // with the latest official version, and record the absolute latest in
+  // 'latest_dev' so we can correctly decide if there's a newer release
+  // than our current snapshot.
+  if ($project_data['install_type'] == 'dev') {
+    if (isset($project_data['dev_version']) && $available['releases'][$project_data['dev_version']]['date'] > $available['releases'][$project_data['latest_version']]['date']) {
+      $project_data['latest_dev'] = $project_data['dev_version'];
+    }
+    else {
+      $project_data['latest_dev'] = $project_data['latest_version'];
+    }
+  }
+
+  // Figure out the status, based on what we've seen and the install type.
+  switch ($project_data['install_type']) {
+    case 'official':
+      if ($project_data['existing_version'] === $project_data['recommended'] || $project_data['existing_version'] === $project_data['latest_version']) {
+        $project_data['status'] = UPDATE_CURRENT;
+      }
+      else {
+        $project_data['status'] = UPDATE_NOT_CURRENT;
+      }
+      break;
+
+    case 'dev':
+      $latest = $available['releases'][$project_data['latest_dev']];
+      if (empty($project_data['datestamp'])) {
+        $project_data['status'] = UPDATE_NOT_CHECKED;
+        $project_data['reason'] = t('Unknown release date');
+      }
+      elseif (($project_data['datestamp'] + 100 > $latest['date'])) {
+        $project_data['status'] = UPDATE_CURRENT;
+      }
+      else {
+        $project_data['status'] = UPDATE_NOT_CURRENT;
+      }
+      break;
+
+    default:
+      $project_data['status'] = UPDATE_UNKNOWN;
+      $project_data['reason'] = t('Invalid info');
+  }
+}
+
+/**
+ * Retrieves data from {cache_update} or empties the cache when necessary.
+ *
+ * Two very expensive arrays computed by this module are the list of all
+ * installed modules and themes (and .info data, project associations, etc), and
+ * the current status of the site relative to the currently available releases.
+ * These two arrays are cached in the {cache_update} table and used whenever
+ * possible. The cache is cleared whenever the administrator visits the status
+ * report, available updates report, or the module or theme administration
+ * pages, since we should always recompute the most current values on any of
+ * those pages.
+ *
+ * Note: while both of these arrays are expensive to compute (in terms of disk
+ * I/O and some fairly heavy CPU processing), neither of these is the actual
+ * data about available updates that we have to fetch over the network from
+ * updates.drupal.org. That information is stored with the
+ * 'update_available_releases' cache ID -- it needs to persist longer than 1
+ * hour and never get invalidated just by visiting a page on the site.
+ *
+ * @param $cid
+ *   The cache ID of data to return from the cache. Valid options are
+ *   'update_project_data' and 'update_project_projects'.
+ *
+ * @return
+ *   The cached value of the $projects array generated by
+ *   update_calculate_project_data() or update_get_projects(), or an empty array
+ *   when the cache is cleared.
+ */
+function update_project_cache($cid) {
+  $projects = array();
+
+  // On certain paths, we should clear the cache and recompute the projects for
+  // update status of the site to avoid presenting stale information.
+  $q = $_GET['q'];
+  $paths = array(
+    'admin/modules',
+    'admin/modules/update',
+    'admin/appearance',
+    'admin/appearance/update',
+    'admin/reports',
+    'admin/reports/updates',
+    'admin/reports/updates/update',
+    'admin/reports/status',
+    'admin/reports/updates/check',
+  );
+  if (in_array($q, $paths)) {
+    _update_cache_clear($cid);
+  }
+  else {
+    $cache = _update_cache_get($cid);
+    if (!empty($cache->data) && $cache->expire > REQUEST_TIME) {
+      $projects = $cache->data;
+    }
+  }
+  return $projects;
+}
+
+/**
+ * Filters the project .info data to only save attributes we need.
+ *
+ * @param array $info
+ *   Array of .info file data as returned by drupal_parse_info_file().
+ *
+ * @return
+ *   Array of .info file data we need for the update manager.
+ *
+ * @see _update_process_info_list()
+ */
+function update_filter_project_info($info) {
+  $whitelist = array(
+    '_info_file_ctime',
+    'datestamp',
+    'major',
+    'name',
+    'package',
+    'project',
+    'project status url',
+    'version',
+  );
+  return array_intersect_key($info, drupal_map_assoc($whitelist));
+}