Performs a cached file system scan as a fallback when searching for a file.

This function looks for the requested file by triggering a file scan, caching the new location if the file has moved and caching the miss if the file is missing. If a file had been marked as missing in a previous file scan, or if it has been marked as moved and is still in the last known location, no new file scan will be performed.

Parameters

string $type: The type of the item (theme, theme_engine, module, profile).

string $name: The name of the item for which the filename is requested.

bool $trigger_error: Whether to trigger an error when a file is missing or has unexpectedly moved.

bool $database_unavailable: Whether this function is being called because the Drupal database could not be queried for the file's location.

Return value

The filename of the requested item or NULL if the item is not found.

See also

drupal_get_filename()

1 call to _drupal_get_filename_fallback()

drupal_get_filename in includes/bootstrap.inc

Returns and optionally sets the filename for a system resource.

File

includes/bootstrap.inc, line 981

Code

function _drupal_get_filename_fallback($type, $name, $trigger_error, $database_unavailable) {
    $file_scans =& _drupal_file_scan_cache();
    $filename = NULL;
    // If the cache indicates that the item is missing, or we can verify that the
    // item exists in the location the cache says it exists in, use that.
    if (isset($file_scans[$type][$name]) && ($file_scans[$type][$name] === FALSE || file_exists($file_scans[$type][$name]))) {
        $filename = $file_scans[$type][$name];
    }
    else {
        $filename = _drupal_get_filename_perform_file_scan($type, $name);
        // Update the static cache, and mark the persistent cache for updating at
        // the end of the page request. See drupal_file_scan_write_cache().
        $file_scans[$type][$name] = $filename;
        $file_scans['#write_cache'] = TRUE;
    }
    // If requested, trigger a user-level warning about the missing or
    // unexpectedly moved file. If the database was unavailable, do not trigger a
    // warning in the latter case, though, since if the {system} table could not
    // be queried there is no way to know if the location found here was
    // "unexpected" or not.
    if ($trigger_error) {
        $error_type = $filename === FALSE ? 'missing' : 'moved';
        if ($error_type == 'missing' || !$database_unavailable) {
            _drupal_get_filename_fallback_trigger_error($type, $name, $error_type);
        }
    }
    // The cache stores FALSE for files that aren't found (to be able to
    // distinguish them from files that have not yet been searched for), but
    // drupal_get_filename() expects NULL for these instead, so convert to NULL
    // before returning.
    if ($filename === FALSE) {
        $filename = NULL;
    }
    return $filename;
}

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