From 43593083f5e507b563bddc7d8d9c6022a9d7fab4 Mon Sep 17 00:00:00 2001
From: Yann Duplouy <yann.duplouy@inria.fr>
Date: Mon, 27 Apr 2020 09:53:58 +0200
Subject: [PATCH 1/1] Tries to handle IO errors

---
 include/xbt/random.hpp | 20 ++++++--------------
 src/xbt/random.cpp     | 40 +++++++++++++++++++++++++++++++++++-----
 2 files changed, 41 insertions(+), 19 deletions(-)

diff --git a/include/xbt/random.hpp b/include/xbt/random.hpp
index 83c8cbf240..81572c78ff 100644
--- a/include/xbt/random.hpp
+++ b/include/xbt/random.hpp
@@ -40,20 +40,12 @@ public:
   /**
    * @brief Read the state of the Mersenne-Twister RNG from a file
    */
-  void read_state(std::string filename)
-  {
-    std::ifstream file(filename);
-    file >> mt19937_gen;
-  }
+  bool read_state(std::string filename);
 
   /**
    * @brief Write the state of the Mersenne-Twister RNG to a file
    */
-  void write_state(std::string filename)
-  {
-    std::ofstream file(filename);
-    file << mt19937_gen;
-  }
+  bool write_state(std::string filename);
 
   /**
    * @brief Draws an integer number uniformly in range [min, max] (min and max included)
@@ -133,14 +125,14 @@ void set_implem_std();
 void set_mersenne_seed(int);
 
 /**
- * @brief Read the state of the Mersenne-Twister RNG from a file
+ * @brief Read the state of the Mersenne-Twister RNG from a file.
  */
-void read_mersenne_state(std::string filename);
+bool read_mersenne_state(std::string filename);
 
 /**
- * @brief Write the state of the Mersenne-Twister RNG to a file
+ * @brief Write the state of the Mersenne-Twister RNG to a file.
  */
-void write_mersenne_state(std::string filename);
+bool write_mersenne_state(std::string filename);
 
 /**
  * @brief Draws an integer number uniformly in range [min, max] (min and max included)
diff --git a/src/xbt/random.cpp b/src/xbt/random.cpp
index 3b2962fb85..004418eadd 100644
--- a/src/xbt/random.cpp
+++ b/src/xbt/random.cpp
@@ -3,16 +3,46 @@
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
-#include "xbt/random.hpp"
 #include "xbt/asserts.h"
+#include <fstream>
+#include <iostream>
 #include <limits>
 #include <memory>
 #include <string>
+#include <xbt/log.hpp>
+#include <xbt/random.hpp>
+
+XBT_LOG_EXTERNAL_CATEGORY(xbt);
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_random, xbt, "Random");
 
 namespace simgrid {
 namespace xbt {
 namespace random {
 
+bool Random::read_state(std::string filename)
+{
+  std::ifstream file(filename);
+  if (file) {
+    file >> mt19937_gen;
+    return true;
+  } else {
+    XBT_WARN("Could not open %s and thus not save the RNG state.", filename.c_str());
+    return false;
+  }
+}
+
+bool Random::write_state(std::string filename)
+{
+  std::ofstream file(filename);
+  if (file) {
+    file << mt19937_gen;
+    return false;
+  } else {
+    XBT_WARN("Could not open %s and thus not read the RNG state.", filename.c_str());
+    return false;
+  }
+}
+
 int StdRandom::uniform_int(int min, int max)
 {
   std::uniform_int_distribution<> dist(min, max);
@@ -93,14 +123,14 @@ void set_mersenne_seed(int seed)
   default_random->set_seed(seed);
 }
 
-void read_mersenne_state(std::string filename)
+bool read_mersenne_state(std::string filename)
 {
-  default_random->read_state(filename);
+  return default_random->read_state(filename);
 }
 
-void write_mersenne_state(std::string filename)
+bool write_mersenne_state(std::string filename)
 {
-  default_random->write_state(filename);
+  return default_random->write_state(filename);
 }
 
 int uniform_int(int min, int max)
-- 
2.20.1