type: use empty to access ds_names

Fix some potential undefined index errors by using the empty function to
access ds_names in type other than default.

3 files changed, 3 insertions, 3 deletions

diff --git a/type/GenericIO.class.php b/type/GenericIO.class.php
index 3425f3e..231c098 100644
--- a/type/GenericIO.class.php
+++ b/type/GenericIO.class.php
@@ -56,7 +56,7 @@ class Type_GenericIO extends Type_Default {
 
                 $i = 0;
                 foreach($sources as $source) {
-                        $dsname = $this->ds_names[$source] != '' ? $this->ds_names[$source] : $source;
+                        $dsname = empty($this->ds_names[$source]) ? $source : $this->ds_names[$source];
                         $rrdgraph[] = sprintf('"LINE1:avg_%s%s#%s:%s"', crc32hex($source), $i == 1 ? '_neg' : '', $this->colors[$source], $this->rrd_escape($dsname));
                         $rrdgraph[] = sprintf('"GPRINT:min_%s:MIN:%s Min,"', crc32hex($source), $this->rrd_format);
                         $rrdgraph[] = sprintf('"GPRINT:avg_%s:AVERAGE:%s Avg,"', crc32hex($source), $this->rrd_format);
diff --git a/type/GenericStacked.class.php b/type/GenericStacked.class.php
index 5d1a556..63d7f33 100644
--- a/type/GenericStacked.class.php
+++ b/type/GenericStacked.class.php
@@ -49,7 +49,7 @@ class Type_GenericStacked extends Type_Default {
 
                 $c = 0;
                 foreach ($sources as $source) {
-                        $dsname = $this->ds_names[$source] != '' ? $this->ds_names[$source] : $source;
+                        $dsname = empty($this->ds_names[$source]) ? $source : $this->ds_names[$source];
                         $color = is_array($this->colors) ? (isset($this->colors[$source])?$this->colors[$source]:$this->colors[$c++]) : $this->colors;
                         $rrdgraph[] = sprintf('"LINE1:area_%s#%s:%s"', crc32hex($source), $this->validate_color($color), $this->rrd_escape($dsname));
                         $rrdgraph[] = sprintf('"GPRINT:min_%s:MIN:%s Min,"', crc32hex($source), $this->rrd_format);
diff --git a/type/Uptime.class.php b/type/Uptime.class.php
index 17bcb9a..4ada117 100644
--- a/type/Uptime.class.php
+++ b/type/Uptime.class.php
@@ -41,7 +41,7 @@ class Type_Uptime extends Type_Default {
 
                 $c = 0;
                 foreach ($sources as $source) {
-                        $dsname = $this->ds_names[$source] != '' ? $this->ds_names[$source] : $source;
+                        $dsname = empty($this->ds_names[$source]) ? $source : $this->ds_names[$source];
                         $color = is_array($this->colors) ? (isset($this->colors[$source])?$this->colors[$source]:$this->colors[$c++]) : $this->colors;
 
                         //current value