Hopefully fix error handling (including EAGAIN) in FileGroup.

diff --git a/src/lib/file_group.cc b/src/lib/file_group.cc
index c2ff047af3d955c539384a5ed8105b977aa2c4cb..e18b9824e27181543ab271546ac6853d985f90a9 100644 (file)
--- a/src/lib/file_group.cc
+++ b/src/lib/file_group.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2013-2014 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2013-2018 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -22,11 +22,12 @@
  *  @brief FileGroup class.
  */
 
-#include <cstdio>
-#include <sndfile.h>
 #include "file_group.h"
 #include "exceptions.h"
 #include "cross.h"
+#include "compose.hpp"
+#include <sndfile.h>
+#include <cstdio>
 #include <iostream>
 
 using std::vector;
@@ -147,7 +148,7 @@ FileGroup::seek (int64_t pos, int whence) const
 /** Try to read some data from the current position into a buffer.
  *  @param buffer Buffer to write data into.
  *  @param amount Number of bytes to read.
- *  @return Number of bytes read, or -1 in the case of error.
+ *  @return Number of bytes read.
  */
 int
 FileGroup::read (uint8_t* buffer, int amount) const
@@ -161,11 +162,17 @@ FileGroup::read (uint8_t* buffer, int amount) const
                        break;
                }
 
-               /* See if there is another file to use */
-               if ((_current_path + 1) >= _paths.size()) {
-                       break;
+               if (ferror(_current_file) && errno != EAGAIN) {
+                       throw FileError (String::compose("fread error %1", errno), _paths[_current_path]);
+               }
+
+               if (feof (_current_file)) {
+                       /* See if there is another file to use */
+                       if ((_current_path + 1) >= _paths.size()) {
+                               break;
+                       }
+                       ensure_open_path (_current_path + 1);
                }
-               ensure_open_path (_current_path + 1);
        }
 
        return read;