From 37ba442bc1c310615f25ba90ba11b424423a7928 Mon Sep 17 00:00:00 2001
From: Shahram Najm <masn@ecmwf.int>
Date: Wed, 21 Nov 2018 15:14:45 +0000
Subject: [PATCH] Python3: Fix for writing GRIB data

---
 python/grib_interface.c   | 16 +++++++++++-----
 python/gribapi/gribapi.py |  2 ++
 python/gribapi_swig.i     | 17 ++++++++++++++---
 python/swig_wrap_numpy.c  |  6 ++----
 4 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/python/grib_interface.c b/python/grib_interface.c
index a12941060..e8b47ad8a 100644
--- a/python/grib_interface.c
+++ b/python/grib_interface.c
@@ -1371,8 +1371,8 @@ int grib_c_new_from_file(FILE* f, int fd, char* fname, int* gid, int headers_onl
         if (p) {
             h=grib_new_from_file(0,p,headers_only,&err);//use cached value
         } else {
-            h=grib_new_from_file(0,f,headers_only,&err);//get new FILE*
-            store_file_info(fd, f);
+            h=grib_new_from_file(0,f,headers_only,&err);//use FILE pointer passed in
+            store_file_info(fd, f); //store it for next time
         }
 
         if(h){
@@ -1382,7 +1382,7 @@ int grib_c_new_from_file(FILE* f, int fd, char* fname, int* gid, int headers_onl
             *gid=-1;
             if (err == GRIB_SUCCESS) {
                 /*printf("C grib_c_new_from_file: GRIB_END_OF_FILE\n");*/
-                return GRIB_END_OF_FILE;
+                return GRIB_END_OF_FILE; //TODO: remove element from cache
             } else {
                 /* A real error occurred */
                 return err;
@@ -2250,6 +2250,7 @@ void grib_c_check(int* err,char* call,char* str)
 
 int grib_c_write(int* gid, FILE* f)
 {
+    int err = 0;
     grib_handle *h = get_handle(*gid);
     const void* mess = NULL;
     size_t mess_len = 0;
@@ -2257,12 +2258,17 @@ int grib_c_write(int* gid, FILE* f)
     if(!f) return GRIB_INVALID_FILE;
     if (!h) return GRIB_INVALID_GRIB;
 
-    grib_get_message(h,&mess,&mess_len);
+    err = grib_get_message(h,&mess,&mess_len);
+    if (err) return err;
     if(fwrite(mess,1, mess_len,f) != mess_len) {
         perror("grib_write");
         return GRIB_IO_PROBLEM;
     }
-
+    err = fflush(f);
+    if(err) {
+        perror("write flush");
+        return GRIB_IO_PROBLEM;
+    }
     return GRIB_SUCCESS;
 }
 
diff --git a/python/gribapi/gribapi.py b/python/gribapi/gribapi.py
index 08f216b9e..46323b071 100644
--- a/python/gribapi/gribapi.py
+++ b/python/gribapi/gribapi.py
@@ -259,6 +259,8 @@ def bufr_new_from_file(fileobj, headers_only=False):
     @return               id of the BUFR loaded in memory
     @exception GribInternalError
     """
+    fd = fileobj.fileno()
+    fn = fileobj.name
     err, bufrid = _internal.grib_c_new_bufr_from_file(fileobj, headers_only, 0)
     if err:
         if err == _internal.GRIB_END_OF_FILE:
diff --git a/python/gribapi_swig.i b/python/gribapi_swig.i
index ef5d26811..da49ef14f 100644
--- a/python/gribapi_swig.i
+++ b/python/gribapi_swig.i
@@ -17,9 +17,7 @@
 import_array();
 %}
 
-/* OLD: Converts a PyFile instance to a stdio FILE* */
-
-/* OLD: FIXME: Can we make this ro/rw ? */
+/* Converts a PyFile instance to a stdio FILE* for reading binary files */
 %typemap(in) FILE* {
   int fileDescriptor = PyObject_AsFileDescriptor($input);
   /*printf("swig.i fileDescriptor=%d\n", fileDescriptor);*/
@@ -70,6 +68,19 @@ int grib_c_new_from_message(int *INOUT, char *binmsg, size_t *INPUT);
 int grib_c_count_in_file(FILE* f,int* OUTPUT);
 // ---
 
+/* Converts a PyFile instance to a stdio FILE* for writing binary files */
+%typemap(in) FILE* {
+  int fileDescriptor = PyObject_AsFileDescriptor($input);
+  if(fileDescriptor >= 0) {
+    /* Convert file descriptor to a FILE pointer */
+    $1 = fdopen(fileDescriptor,"wb");
+  }
+  else {
+    PyErr_SetString(PyExc_TypeError, "$1_name must be a file type.");
+    return NULL;
+  }
+}
+
 // grib handle operations
 int grib_c_release(int* gid);
 int grib_c_write(int* gid, FILE* f);
diff --git a/python/swig_wrap_numpy.c b/python/swig_wrap_numpy.c
index b06bc37d2..0c98094fe 100644
--- a/python/swig_wrap_numpy.c
+++ b/python/swig_wrap_numpy.c
@@ -6156,10 +6156,9 @@ SWIGINTERN PyObject *_wrap_grib_c_write(PyObject *SWIGUNUSEDPARM(self), PyObject
   }
   {
     int fileDescriptor = PyObject_AsFileDescriptor(obj1);
-    /*printf("swig.i fileDescriptor=%d\n", fileDescriptor);*/
     if(fileDescriptor >= 0) {
       /* Convert file descriptor to a FILE pointer */
-      arg2 = fdopen(fileDescriptor,"rb"); // needs to be rb+ (or wb) for write
+      arg2 = fdopen(fileDescriptor,"wb");
     }
     else {
       PyErr_SetString(PyExc_TypeError, "f must be a file type.");
@@ -6572,10 +6571,9 @@ SWIGINTERN PyObject *_wrap_grib_c_multi_write(PyObject *SWIGUNUSEDPARM(self), Py
   }
   {
     int fileDescriptor = PyObject_AsFileDescriptor(obj1);
-    /*printf("swig.i fileDescriptor=%d\n", fileDescriptor);*/
     if(fileDescriptor >= 0) {
       /* Convert file descriptor to a FILE pointer */
-      arg2 = fdopen(fileDescriptor,"rb"); // needs to be rb+ (or wb) for write
+      arg2 = fdopen(fileDescriptor,"wb");
     }
     else {
       PyErr_SetString(PyExc_TypeError, "f must be a file type.");