From: Martin Quinson <martin.quinson@loria.fr>
Date: Fri, 30 Mar 2018 22:56:58 +0000 (+0200)
Subject: config::Flag: allow to pass a map of the valid values
X-Git-Tag: v3.20~570
X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/commitdiff_plain/36b1fa831a191c389b1c907bfa35655b4283f06d

config::Flag: allow to pass a map of the valid values
---

diff --git a/include/xbt/config.hpp b/include/xbt/config.hpp
index 236d87f962..f773739c86 100644
--- a/include/xbt/config.hpp
+++ b/include/xbt/config.hpp
@@ -12,6 +12,7 @@
 
 #include <functional>
 #include <initializer_list>
+#include <map>
 #include <stdexcept>
 #include <string>
 #include <type_traits>
@@ -19,6 +20,7 @@
 
 #include <xbt/base.h>
 #include <xbt/config.h>
+#include <xbt/sysdep.h>
 
 namespace simgrid {
 namespace config {
@@ -152,7 +154,32 @@ bindFlag(T& value, const char* name, const char* description,
     }
   ));
 }
-
+template <class T, class F>
+typename std::enable_if<std::is_same<void, decltype(std::declval<F>()(std::declval<const T&>()))>::value, void>::type
+bindFlag(T& value, const char* name, const char* description, std::map<T, std::string> valid_values, F callback)
+{
+  declareFlag(name, description, value,
+              std::function<void(const T&)>([&value, name, valid_values, callback](const T& val) {
+                callback(val);
+                bool found = false;
+                for (auto kv : valid_values) {
+                  if (kv.first == val)
+                    found = true;
+                }
+                if (not found || std::string(val) == "help") {
+                  std::string mesg;
+                  if (std::string(val) == "help")
+                    mesg = std::string("\nPossible values for option ") + name + ":\n";
+                  else
+                    mesg = std::string("\nInvalid value '") + val + "' for option " + name + ". Possible values:\n";
+                  for (auto kv : valid_values)
+                    mesg += "  - '" + std::string(kv.first) + "': " + kv.second +
+                            (kv.first == value ? "  <=== DEFAULT" : "") + "\n";
+                  xbt_die("%s", mesg.c_str());
+                }
+                value = std::move(val);
+              }));
+}
 /** Bind a variable to configuration flag
  *
  *  <pre><code>
@@ -202,12 +229,24 @@ public:
     simgrid::config::bindFlag(value_, name, desc);
   }
 
+  /* A constructor accepting a callback that will be passed the parameter.
+   * It can either return a boolean (informing whether the parameter is valid), or returning void.
+   */
   template<class F>
   Flag(const char* name, const char* desc, T value, F callback) : value_(value)
   {
     simgrid::config::bindFlag(value_, name, desc, std::move(callback));
   }
 
+  /* A constructor accepting a map of valid values -> their description,
+   * and producing an informative error message when an invalid value is passed, or when help is passed as a value.
+   */
+  template <class F>
+  Flag(const char* name, const char* desc, T value, std::map<T, std::string> valid_values, F callback) : value_(value)
+  {
+    simgrid::config::bindFlag(value_, name, desc, std::move(valid_values), std::move(callback));
+  }
+
   // No copy:
   Flag(Flag const&) = delete;
   Flag& operator=(Flag const&) = delete;