Handle reading empty file in ReversedFileReader

[friendica.git] / src / Util / ReversedFileReader.php

diff --git a/src/Util/ReversedFileReader.php b/src/Util/ReversedFileReader.php
index c4fe131aee9d68d8766b99a9edaabfabd97d518d..92c8cced184e1db5c8b602815ed3a4a9373af302 100644 (file)
--- a/src/Util/ReversedFileReader.php
+++ b/src/Util/ReversedFileReader.php
@@ -70,6 +70,11 @@ class ReversedFileReader implements \Iterator
                return $this;
        }
 
+       /**
+        * Read $size bytes behind last position
+        *
+        * @return string
+        */
        private function _read($size)
        {
                $this->pos -= $size;
@@ -77,6 +82,12 @@ class ReversedFileReader implements \Iterator
                return fread($this->fh, $size);
        }
 
+       /**
+        * Read next line from end of file
+        * Return null if no lines are left to read
+        *
+        * @return ?string
+        */
        private function _readline()
        {
                $buffer = & $this->buffer;
@@ -84,6 +95,9 @@ class ReversedFileReader implements \Iterator
                        if ($this->pos == 0) {
                                return array_pop($buffer);
                        }
+                       if (is_null($buffer)) {
+                               return null;
+                       }
                        if (count($buffer) > 1) {
                                return array_pop($buffer);
                        }
@@ -91,12 +105,24 @@ class ReversedFileReader implements \Iterator
                }
        }
 
+       /**
+        * Fetch next line from end and set it as current iterator value.
+        *
+        * @see Iterator::next()
+        * @return void
+        */
        public function next()
        {
                ++$this->key;
                $this->value = $this->_readline();
        }
 
+       /**
+        * Rewind iterator to the first line at the end of file
+        *
+        * @see Iterator::rewind()
+        * @return void
+        */
        public function rewind()
        {
                if ($this->filesize > 0) {
@@ -108,16 +134,34 @@ class ReversedFileReader implements \Iterator
                }
        }
 
+       /**
+        * Return current line number, starting from zero at the end of file
+        *
+        * @see Iterator::key()
+        * @return int
+        */
        public function key()
        {
                return $this->key;
        }
 
+       /**
+        * Return current line
+        *
+        * @see Iterator::current()
+        * @return string
+        */
        public function current()
        {
                return $this->value;
        }
 
+       /**
+        * Checks if current iterator value is valid, that is, we readed all lines in files
+        *
+        * @see Iterator::valid()
+        * @return bool
+        */
        public function valid()
        {
                return ! is_null($this->value);