Use C++ Flag for context factory selection

diff --git a/include/simgrid/simix.h b/include/simgrid/simix.h
index 4ac35a1..aa4ba62 100644 (file)
--- a/include/simgrid/simix.h
+++ b/include/simgrid/simix.h
@@ -148,7 +148,6 @@ typedef void (*void_pfn_smxprocess_t) (smx_process_t);
 /* for auto-restart function */
 typedef void (*void_pfn_sghost_t) (sg_host_t);
 
-extern char* smx_context_factory_name;
 extern int smx_context_stack_size;
 extern int smx_context_stack_size_was_set;
 extern int smx_context_guard_size;

diff --git a/src/simgrid/sg_config.cpp b/src/simgrid/sg_config.cpp
index 8062d06..a2e3f35 100644 (file)
--- a/src/simgrid/sg_config.cpp
+++ b/src/simgrid/sg_config.cpp
@@ -356,11 +356,6 @@ static void _sg_cfg_cb_clean_atexit(const char *name)
   _sg_do_clean_atexit = xbt_cfg_get_boolean(name);
 }
 
-static void _sg_cfg_cb_context_factory(const char *name)
-{
-  smx_context_factory_name = xbt_cfg_get_string(name);
-}
-
 static void _sg_cfg_cb_context_stack_size(const char *name)
 {
   smx_context_stack_size_was_set = 1;
@@ -546,23 +541,6 @@ void sg_config_init(int *argc, char **argv)
 
     xbt_cfg_register_boolean("verbose-exit", "yes", _sg_cfg_cb_verbose_exit, "Activate the \"do nothing\" mode in Ctrl-C");
 
-    /* context factory */
-    const char *dflt_ctx_fact = "thread";
-    {
-      char *p = description +
-        sprintf(description, "Context factory to use in SIMIX. Possible values: %s", dflt_ctx_fact);
-#if HAVE_UCONTEXT_CONTEXTS
-      dflt_ctx_fact = "ucontext";
-      p += sprintf(p, ", %s", dflt_ctx_fact);
-#endif
-#if HAVE_RAW_CONTEXTS
-      dflt_ctx_fact = "raw";
-      p += sprintf(p, ", %s", dflt_ctx_fact);
-#endif
-      sprintf(p, ".");
-    }
-    xbt_cfg_register_string("contexts/factory", dflt_ctx_fact, _sg_cfg_cb_context_factory, description);
-
     xbt_cfg_register_int("contexts/stack-size", 8*1024, _sg_cfg_cb_context_stack_size, "Stack size of contexts in KiB");
     /* (FIXME: this is unpleasant) Reset this static variable that was altered when setting the default value. */
     smx_context_stack_size_was_set = 0;

diff --git a/src/simix/smx_context.cpp b/src/simix/smx_context.cpp
index 87ea4dc..0a528a0 100644 (file)
--- a/src/simix/smx_context.cpp
+++ b/src/simix/smx_context.cpp
@@ -6,6 +6,12 @@
 /* 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 <utility>
+#include <string>
+
+#include <xbt/config.hpp>
+#include <xbt/range.hpp>
+
 #include "src/internal_config.h"
 #include "xbt/log.h"
 #include "xbt/swag.h"
@@ -35,7 +41,43 @@
 
 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(simix_context, simix, "Context switching mechanism");
 
-char* smx_context_factory_name = NULL; /* factory name specified by --cfg=contexts/factory:value */
+static std::pair<const char*, simgrid::simix::ContextFactoryInitializer> context_factories[] = {
+#if HAVE_RAW_CONTEXTS
+  { "raw", simgrid::simix::raw_factory },
+#endif
+#if HAVE_UCONTEXT_CONTEXTS
+  { "ucontext", simgrid::simix::sysv_factory },
+#endif
+#if HAVE_BOOST_CONTEXTS
+  { "boost", simgrid::simix::boost_factory },
+#endif
+#if HAVE_THREAD_CONTEXTS
+  { "thread", simgrid::simix::thread_factory },
+#endif
+};
+
+static_assert(sizeof(context_factories) != 0,
+  "No context factories are enabled for this build");
+
+// Create the list of possible contexts:
+static inline
+std::string contexts_list()
+{
+  std::string res;
+  const std::size_t n = sizeof(context_factories) / sizeof(context_factories[0]);
+  std::size_t i = 0;
+  for (std::size_t i = 1; i != n; ++i) {
+    res += ", ";
+    res += context_factories[i].first;
+  }
+  return res;
+}
+
+static simgrid::config::Flag<std::string> context_factory_name(
+  "contexts/factory",
+  (std::string("Possible values: ")+contexts_list()).c_str(),
+  context_factories[0].first);
+
 int smx_context_stack_size;
 int smx_context_stack_size_was_set = 0;
 int smx_context_guard_size;
@@ -50,61 +92,54 @@ static int smx_parallel_contexts = 1;
 static int smx_parallel_threshold = 2;
 static e_xbt_parmap_mode_t smx_parallel_synchronization_mode = XBT_PARMAP_DEFAULT;
 
-/** 
- * This function is called by SIMIX_global_init() to initialize the context module.
- */
-void SIMIX_context_mod_init(void)
+static inline
+void invalid_context_factory()
 {
-#if HAVE_THREAD_CONTEXTS && !HAVE_THREAD_LOCAL_STORAGE
-  /* the __thread storage class is not available on this platform:
-   * use getspecific/setspecific instead to store the current context in each thread */
-  xbt_os_thread_key_create(&smx_current_context_key);
-#endif
-  if (!simix_global->context_factory) {
-    /* select the context factory to use to create the contexts */
-    if (simgrid::simix::factory_initializer)
-      simix_global->context_factory = simgrid::simix::factory_initializer();
-    else { /* use the factory specified by --cfg=contexts/factory:value */
-#if HAVE_THREAD_CONTEXTS
-      if (!strcmp(smx_context_factory_name, "thread"))
-        simix_global->context_factory = simgrid::simix::thread_factory();
-#else
-      if (0);
-#endif
-#if HAVE_UCONTEXT_CONTEXTS
-      else if (!strcmp(smx_context_factory_name, "ucontext"))
-        simix_global->context_factory = simgrid::simix::sysv_factory();
-#endif
+  XBT_ERROR("Invalid context factory specified. Valid factories on this machine:");
 #if HAVE_RAW_CONTEXTS
-      else if (!strcmp(smx_context_factory_name, "raw"))
-        simix_global->context_factory = simgrid::simix::raw_factory();
-#endif
-#if HAVE_BOOST_CONTEXTS
-      else if (!strcmp(smx_context_factory_name, "boost"))
-        simix_global->context_factory = simgrid::simix::boost_factory();
-#endif
-      else {
-        XBT_ERROR("Invalid context factory specified. Valid factories on this machine:");
-#if HAVE_RAW_CONTEXTS
-        XBT_ERROR("  raw: high performance context factory implemented specifically for SimGrid");
+  XBT_ERROR("  raw: high performance context factory implemented specifically for SimGrid");
 #else
-        XBT_ERROR("  (raw contexts were disabled at compilation time on this machine -- check configure logs for details)");
+  XBT_ERROR("  (raw contexts were disabled at compilation time on this machine -- check configure logs for details)");
 #endif
 #if HAVE_UCONTEXT_CONTEXTS
-        XBT_ERROR("  ucontext: classical system V contexts (implemented with makecontext, swapcontext and friends)");
+  XBT_ERROR("  ucontext: classical system V contexts (implemented with makecontext, swapcontext and friends)");
 #else
-        XBT_ERROR("  (ucontext was disabled at compilation time on this machine -- check configure logs for details)");
+  XBT_ERROR("  (ucontext was disabled at compilation time on this machine -- check configure logs for details)");
 #endif
 #if HAVE_BOOST_CONTEXTS
-        XBT_ERROR("  boost: this uses the boost libraries context implementation");
+  XBT_ERROR("  boost: this uses the boost libraries context implementation");
 #else
-        XBT_ERROR("  (boost was disabled at compilation time on this machine -- check configure logs for details. Did you install the libboost-context-dev package?)");
+  XBT_ERROR("  (boost was disabled at compilation time on this machine -- check configure logs for details. Did you install the libboost-context-dev package?)");
 #endif
-        XBT_ERROR("  thread: slow portability layer using pthreads as provided by gcc");
-        xbt_die("Please use a valid factory.");
-      }
-    }
+  XBT_ERROR("  thread: slow portability layer using pthreads as provided by gcc");
+  xbt_die("Please use a valid factory.");
+}
+
+/**
+ * This function is called by SIMIX_global_init() to initialize the context module.
+ */
+void SIMIX_context_mod_init(void)
+{
+#if HAVE_THREAD_CONTEXTS && !HAVE_THREAD_LOCAL_STORAGE
+  /* the __thread storage class is not available on this platform:
+   * use getspecific/setspecific instead to store the current context in each thread */
+  xbt_os_thread_key_create(&smx_current_context_key);
+#endif
+  if (simix_global->context_factory)
+    return;
+  /* select the context factory to use to create the contexts */
+  if (simgrid::simix::factory_initializer) {
+    simix_global->context_factory = simgrid::simix::factory_initializer();
+    return;
   }
+  /* use the factory specified by --cfg=contexts/factory:value */
+  for (auto const& factory : context_factories)
+    if (context_factory_name == factory.first) {
+      simix_global->context_factory = factory.second();
+      break;
+    }
+  if (simix_global->context_factory == nullptr)
+    invalid_context_factory();
 }
 
 /**