From 4f278195a42ea0f254114c92043b6ba6ecdc6b0a Mon Sep 17 00:00:00 2001
From: Timur Alperovich <timuralp@swiftstack.com>
Date: Mon, 7 Mar 2016 15:09:20 -0800
Subject: [PATCH] Use the check_backend_available function.

Eliminates the spurrious syslog messages and is a cleaner mechanism
for querying all of the available backends on a system.
---
 pyeclib/ec_iface.py         | 19 ++++++++-----------
 src/c/pyeclib_c/pyeclib_c.c | 17 +++++++++++++++++
 2 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/pyeclib/ec_iface.py b/pyeclib/ec_iface.py
index d4775e2..9310ae7 100644
--- a/pyeclib/ec_iface.py
+++ b/pyeclib/ec_iface.py
@@ -26,6 +26,7 @@ from .enum import Enum
 from .enum import unique
 from .utils import create_instance
 from .utils import positive_int_value
+from pyeclib_c import check_backend_available
 
 
 def PyECLibVersion(z, y, x):
@@ -476,18 +477,14 @@ ALL_EC_TYPES = [
 def _PyECLibValidECTypes():
     available_ec_types = []
     for _type in ALL_EC_TYPES:
-        driver = None
-        try:
-            if _type is 'shss':
-                _m = 4
-            else:
-                _m = 5
-            driver = ECDriver(k=10, m=_m, ec_type=_type, validate=True)
-            if driver:
-                available_ec_types.append(_type)
-        except:
-            # ignore any errors, assume backend not available
+        if _type.startswith('flat_xor_hd'):
+            int_type = PyECLib_EC_Types.get_by_name('flat_xor_hd')
+        else:
+            int_type = PyECLib_EC_Types.get_by_name(_type)
+        if not int_type:
             continue
+        if check_backend_available(int_type.value):
+            available_ec_types.append(_type)
     return available_ec_types
 
 
diff --git a/src/c/pyeclib_c/pyeclib_c.c b/src/c/pyeclib_c/pyeclib_c.c
index 8b359f1..01fc13d 100644
--- a/src/c/pyeclib_c/pyeclib_c.c
+++ b/src/c/pyeclib_c/pyeclib_c.c
@@ -1172,6 +1172,22 @@ exit:
   return ret_obj;
 }
 
+static PyObject*
+pyeclib_c_check_backend_available(PyObject *self, PyObject *args)
+{
+    const ec_backend_id_t backend_id;
+
+    if (!PyArg_ParseTuple(args, "i", &backend_id)) {
+        pyeclib_c_seterr(-EINVALIDPARAMS, "pyeclib_c_check_backend_available ERROR: ");
+        return NULL;
+    }
+
+    if (liberasurecode_backend_available(backend_id)) {
+        Py_RETURN_TRUE;
+    }
+
+    Py_RETURN_FALSE;
+}
 
 static PyMethodDef PyECLibMethods[] = {
     {"init",  pyeclib_c_init, METH_VARARGS, "Initialize a new erasure encoder/decoder"},
@@ -1182,6 +1198,7 @@ static PyMethodDef PyECLibMethods[] = {
     {"get_segment_info", pyeclib_c_get_segment_info, METH_VARARGS, "Return segment and fragment size information needed when encoding a segmented stream"},
     {"get_metadata", pyeclib_c_get_metadata, METH_VARARGS, "Get the integrity checking metadata for a fragment"},
     {"check_metadata", pyeclib_c_check_metadata, METH_VARARGS, "Check the integrity checking metadata for a set of fragments"},
+    {"check_backend_available", pyeclib_c_check_backend_available, METH_VARARGS, "Check if a backend is available"},
     {NULL, NULL, 0, NULL}        /* Sentinel */
 };