Added a helper function for displaying if the given executable is accessible.

This can be used in admin setting forms and else where to indicate if the given
executable is availible, and if its version requirements are met.

includes/utilities.inc

@@ -433,7 +433,7 @@ function islandora_prepare_new_object($namespace = NULL, $label = NULL, $datastr
     $mimetype = isset($ds['mimetype']) ? $ds['mimetype'] : 'text/xml';
     // Default 'Managed'
     $control_group = (isset($ds['control_group']) && in_array($ds['control_group'], array('X', 'M', 'R', 'E'))) ? $ds['control_group'] : 'M';
-   
+
     $ds_uri = FALSE;
     if (file_valid_uri($ds['datastream_file'])) {
       $datastream_file = $ds['datastream_file'];
@@ -441,7 +441,7 @@ function islandora_prepare_new_object($namespace = NULL, $label = NULL, $datastr
     }
     else {
       $datastream_file = url($ds['datastream_file'], array('absolute' => TRUE));
-    } 
+    }
     $datastream = $object->constructDatastream($dsid, $control_group);
     $datastream->label = $label;
     $datastream->mimetype = $mimetype;
@@ -476,3 +476,42 @@ function islandora_display_repository_inaccessible_message() {
              array('!link' => $link));
   drupal_set_message($message, 'error', FALSE);
 }
+
+/**
+ * Create a message stating if the given executable is available.
+ *
+ * If the both the version and required version are given then only if the
+ * version is equal to or greater than the required version the executable
+ * will be considered correct.
+ *
+ * @param string $path
+ *   The absolute path to an executable to check for availability.
+ * @param string $version
+ *   The version of exectuable.
+ * @param string $required_version
+ *   The required version of exectuable.
+ *
+ * @return string
+ *   A message in html detailing if the given executable is accessible.
+ */
+function islandora_executable_available_message($path, $version = NULL, $required_version = NULL) {
+  $available = is_executable($path);
+  if ($available) {
+    $image = theme_image(array('path' => 'misc/watchdog-ok.png', 'attributes' => array()));
+    $message = t('Executable found at @path', array('@path' => $path));
+    if ($version) {
+      $message .= t('<br/>Version: @version', array('@version' => $version));
+    }
+    if ($required_version) {
+      $message .= t('<br/>Required Version: @version', array('@version' => $required_version));
+      if (version_compare($version, $required_version) < 0) {
+        $image = theme_image(array('path' => 'misc/watchdog-error.png', 'attributes' => array()));
+      }
+    }
+  }
+  else {
+    $image = theme_image(array('path' => 'misc/watchdog-error.png', 'attributes' => array()));
+    $message = t('Unable to locate executable at @path', array('@path' => $path));
+  }
+  return $image . $message;
+}