Get file position when attaching an open file descriptor to QFile

This was already being done when attaching to FILE* streams. Doing the
same here makes the API consistent and more usable. Namely, one can use
QFile::pos() to obtain the file position.

Test case verifies this doesn't break support for sequential files. More
thorough test case included in large file support test.

Reviewed-by: Thiago Macieira

1 files changed, 6 insertions, 1 deletions

diff --git a/src/corelib/io/qfile.cpp b/src/corelib/io/qfile.cpp
index 64d8ef3..4dd6185 100644
--- a/src/corelib/io/qfile.cpp
+++ b/src/corelib/io/qfile.cpp
@@ -1120,8 +1120,13 @@ bool QFile::open(int fd, OpenMode mode)
     }
     if(d->openExternalFile(mode, fd)) {
         QIODevice::open(mode);
-        if (mode & Append)
+        if (mode & Append) {
             seek(size());
+        } else {
+            qint64 pos = (qint64)QT_LSEEK(fd, QT_OFF_T(0), SEEK_CUR);
+            if (pos != -1)
+                seek(pos);
+        }
         return true;
     }
     return false;