Use HDF5File with the "with" statement

Created by: 183amir

In python you usually can do something like:

with open(path) as f:
  doc = f.read()

But you cannot do this with the HDF5File class. What is the proper way to add this feature to bob?

Created by: tiagofrepereira2012

In the C++ level you can define in the PyMethodDef two methods called __enter__ and __exit__ (the python name) and you implement the behaviour that you want.

Created by: 183amir

It can also be done in Python:

diff --git a/bob/io/base/__init__.py b/bob/io/base/__init__.py
index 74a868d..a21a357 100644
--- a/bob/io/base/__init__.py
+++ b/bob/io/base/__init__.py
@@ -5,13 +5,34 @@ import bob.core
 import bob.extension
 bob.extension.load_bob_library('bob.io.base', __file__)
 
-from ._library import File, HDF5File, extensions
+from ._library import File as File_C, HDF5File as HDF5File_C, extensions
 from . import version
 from .version import module as __version__
 from .version import api as __api_version__
 
 import os
 
+
+class File(File_C):
+  __doc__ = File_C.__doc__
+
+  def __enter__(self):
+    return self
+
+  def __exit__(self, type, value, traceback):
+    self.close()
+
+
+class HDF5File(HDF5File_C):
+  __doc__ = HDF5File_C.__doc__
+
+  def __enter__(self):
+    return self
+
+  def __exit__(self, type, value, traceback):
+    self.close()
+
+
 def _is_string(s):
   """Returns ``True`` if the given object is a string
 

Created by: tiagofrepereira2012

Just for completeness, the effort in the C++ level (with no documentation :-P )

diff --git a/bob/io/base/hdf5.cpp b/bob/io/base/hdf5.cpp
index d909e54..743c589 100644
--- a/bob/io/base/hdf5.cpp
+++ b/bob/io/base/hdf5.cpp
@@ -217,6 +217,51 @@ BOB_CATCH_MEMBER(exception_message(self, s_close.name()).c_str(), 0);
 }
 
 
+
+
+
+static auto s_enter = bob::extension::FunctionDoc(
+  "__enter__",
+  "ENTER",
+  "ENTER",
+  true
+)
+.add_prototype("")
+;
+static PyObject* PyBobIoHDF5File_enter(PyBobIoHDF5FileObject* self, PyObject *args, PyObject* kwds) {
+BOB_TRY
+  /* Parses input arguments in a single shot */
+  return Py_BuildValue("N",self);
+  
+  
+BOB_CATCH_MEMBER(exception_message(self, s_enter.name()).c_str(), 0);
+}
+
+
+
+static auto s_exit = bob::extension::FunctionDoc(
+  "__exit__",
+  "EXIT",
+  "EXIT",
+  true
+)
+.add_prototype("")
+;
+static PyObject* PyBobIoHDF5File_exit(PyBobIoHDF5FileObject* self, PyObject *args, PyObject* kwds) {
+BOB_TRY
+  /* Parses input arguments in a single shot */
+
+  self->f->close();
+
+
+  Py_RETURN_NONE;
+BOB_CATCH_MEMBER(exception_message(self, s_exit.name()).c_str(), 0);
+}
+
+
+
+
+
 static auto s_cd = bob::extension::FunctionDoc(
   "cd",
   "Changes the current prefix path",
@@ -1886,6 +1931,22 @@ static PyMethodDef PyBobIoHDF5File_methods[] = {
     METH_VARARGS|METH_KEYWORDS,
     s_close.doc()
   },
+
+  {
+    s_enter.name(),
+    (PyCFunction)PyBobIoHDF5File_enter,
+    METH_NOARGS,
+    s_enter.doc()
+  },
+  
+  {
+    s_exit.name(),
+    (PyCFunction)PyBobIoHDF5File_exit,
+    METH_VARARGS,
+    s_exit.doc()
+  },
+
+
   {
     s_flush.name(),
     (PyCFunction)PyBobIoHDF5File_flush,

Created by: 183amir

@tiagofrepereira2012 when you have the time, could please push your C patch?

Created by: tiagofrepereira2012

Sure

Reassigned to @amohammadi

Fixed in 77c107fd

Status changed to closed