From e69661c881f3bbab07fa44547bb9b9796e386135 Mon Sep 17 00:00:00 2001
From: Xavier De Cock <xdecock@gmail.com>
Date: Tue, 22 Mar 2011 15:42:50 +0100
Subject: [PATCH] [FileByteStream] Ensure Stream is seekable before trying to
 seek through this should address bug #187 and allow embedding of url altough
 it's clearly not recommended

---
 .../Swift/ByteStream/FileByteStream.php       | 63 ++++++++++++++++++-
 1 file changed, 61 insertions(+), 2 deletions(-)

diff --git a/lib/classes/Swift/ByteStream/FileByteStream.php b/lib/classes/Swift/ByteStream/FileByteStream.php
index 9494c35ab..367c6f977 100644
--- a/lib/classes/Swift/ByteStream/FileByteStream.php
+++ b/lib/classes/Swift/ByteStream/FileByteStream.php
@@ -37,6 +37,9 @@ class Swift_ByteStream_FileByteStream
   
   /** If magic_quotes_runtime is on, this will be true */
   private $_quotes = false;
+
+  /** If stream is seekable true/false, or null if not known */
+  private $_seekable = null;
   
   /**
    * Create a new FileByteStream for $path.
@@ -100,7 +103,7 @@ public function setReadPointer($byteOffset)
   {
     if (isset($this->_reader))
     {
-      fseek($this->_reader, $byteOffset, SEEK_SET);
+      $this->_seekReadStreamToPosition($byteOffset);
     }
     $this->_offset = $byteOffset;
   }
@@ -130,7 +133,10 @@ private function _getReadHandle()
           'Unable to open file for reading [' . $this->_path . ']'
           );
       }
-      fseek($this->_reader, $this->_offset, SEEK_SET);
+      if ($this->_offset <> 0) {
+        $this->_getReadStreamSeekableStatus();
+        $this->_seekReadStreamToPosition($this->_offset);
+      }
     }
     return $this->_reader;
   }
@@ -160,4 +166,57 @@ private function _resetReadHandle()
     }
   }
   
+  /** Check if ReadOnly Stream is seekable */
+  private function _getReadStreamSeekableStatus() {
+    $metas = stream_get_meta_data($this->_reader);
+    $this->_seekable = $metas['seekable'];
+  }
+  
+  /** Streams in a readOnly stream ensuring copy if needed */
+  private function _seekReadStreamToPosition($offset) {
+    if ($this->_seekable===null) {
+      $this->_getReadStreamSeekableStatus();
+    }
+    if ($this->_seekable === false) {
+      $currentPos = ftell($this->_reader);
+      if ($currentPos<$offset) {
+        $toDiscard = $offset-$currentPos;
+        fread($this->_reader, $toDiscard);
+        return;
+      }
+      $this->_copyReadStream();
+    }
+    fseek($this->_reader, $offset, SEEK_SET);
+  }
+  
+  /** Copy a readOnly Stream to ensure seekability */
+  private function _copyReadStream() {
+    if ($tmpFile = fopen('php://temp/maxmemory:4096', 'w+b'))
+    {
+      /* We have opened a php:// Stream Should work without problem */
+    } 
+    elseif (function_exists('sys_get_temp_dir') && is_writable(sys_get_temp_dir()) && ($tmpFile = tmpfile())) 
+    {
+      /* We have opened a tmpfile */
+    } 
+    else
+    {
+      throw new Swift_IoException('Unable to copy the file to make it seekable, sys_temp_dir is not writable, php://memory not available');
+    }
+    $currentPos = ftell($this->_reader);
+    fclose($this->_reader);
+    $source = fopen($this->_path, 'rb');
+    if (!$source)
+    {
+      throw new Swift_IoException('Unable to open file for copying [' . $this->_path . ']');
+    }
+    fseek($tmpFile, 0, SEEK_SET);
+    while (!feof($source)) 
+    {
+      fwrite($tmpFile, fread($source, 4096));
+    }
+    fseek($tmpFile, $currentPos, SEEK_SET);
+    fclose($source);
+    $this->_reader = $tmpFile;
+  }
 }