public release 4.2.0 - see README.md and CHANGES.md for details

pmsco/helpers.py

@@ -6,6 +6,13 @@ a collection of small and generic code bits mostly collected from the www.
 
 """
 
+import contextlib
+import ctypes
+import io
+import os
+import sys
+from typing import BinaryIO
+
 
 class BraceMessage(object):
     """
@@ -22,3 +29,40 @@ class BraceMessage(object):
 
     def __str__(self):
         return self.fmt.format(*self.args, **self.kwargs)
+
+
+libc = ctypes.CDLL(None)
+c_stdout = ctypes.c_void_p.in_dll(libc, 'stdout')
+
+
+@contextlib.contextmanager
+def stdout_redirected(dest_file: BinaryIO):
+    """
+    A context manager to temporarily redirect stdout to a file.
+
+    Redirects all standard output from Python and the C library to the specified file.
+    This can be used, e.g., to capture output from Fortran code.
+
+    credit: https://eli.thegreenplace.net/2015/redirecting-all-kinds-of-stdout-in-python/
+
+    @param dest_file: binary file open for writing ('wb' mode).
+        This function requires just the fileno function.
+    @return: None
+    """
+
+    original_stdout_fd = sys.stdout.fileno()
+
+    def _redirect_stdout(to_fd):
+        """Redirect stdout to the given file descriptor."""
+        libc.fflush(c_stdout)
+        sys.stdout.close()
+        os.dup2(to_fd, original_stdout_fd)
+        sys.stdout = io.TextIOWrapper(os.fdopen(original_stdout_fd, 'wb'))
+
+    saved_stdout_fd = os.dup(original_stdout_fd)
+    try:
+        _redirect_stdout(dest_file.fileno())
+        yield
+        _redirect_stdout(saved_stdout_fd)
+    finally:
+        os.close(saved_stdout_fd)