diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index b926d882..6347c367 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -38,7 +38,7 @@ set(conky_sources colours.cc combine.cc common.cc conky.cc core.cc
diskio.cc entropy.cc exec.cc fs.cc mail.cc mixer.cc net_stat.cc template.cc
mboxscan.cc read_tcp.cc scroll.cc specials.cc tailhead.cc
temphelper.cc text_object.cc timeinfo.cc top.cc algebra.cc prioqueue.c proc.cc
- user.cc luamm.cc)
+ user.cc luamm.cc data-source.cc)
# add timed thread library
add_library(timed-thread timed-thread.cc)
diff --git a/src/data-source.cc b/src/data-source.cc
new file mode 100644
index 00000000..5ce84d29
--- /dev/null
+++ b/src/data-source.cc
@@ -0,0 +1,106 @@
+/* -*- mode: c++; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: t -*-
+ * vim: ts=4 sw=4 noet ai cindent syntax=cpp
+ *
+ * Conky, a system monitor, based on torsmo
+ *
+ * Please see COPYING for details
+ *
+ * Copyright (C) 2010 Pavel Labath et al.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see .
+ *
+ */
+
+#include
+
+#include "data-source.hh"
+
+#include
+#include
+#include
+#include
+
+namespace conky {
+ namespace {
+ /*
+ * Returned when there is no data available.
+ * An alternative would be to throw an exception, but if we don't want to react too
+ * aggresively when the user e.g. uses a nonexisting variable, then returning NaN will do
+ * just fine.
+ */
+ float NaN = std::numeric_limits::quiet_NaN();
+
+ /*
+ * We cannot construct this object statically, because order of object construction in
+ * different modules is not defined, so register_source could be called before this
+ * object is constructed. Therefore, we create it on the first call to register_source.
+ */
+ typedef std::unordered_map data_sources_t;
+ data_sources_t *data_sources;
+
+ void register_data_source_(const std::string &name, const data_source_factory &factory_func)
+ {
+ struct data_source_constructor {
+ data_source_constructor() { data_sources = new data_sources_t(); }
+ ~data_source_constructor() { delete data_sources; data_sources = NULL; }
+ };
+ static data_source_constructor constructor;
+
+ bool inserted = data_sources->insert({name, factory_func}).second;
+ if(not inserted)
+ throw std::logic_error("Data source with name '" + name + "' already registered");
+ }
+
+ static std::shared_ptr
+ disabled_source_factory(lua::state &l, const std::string &name, const std::string &setting)
+ {
+ // XXX some generic way of reporting errors? NORM_ERR?
+ std::cerr << "Support for setting '" << name
+ << "' has been disabled during compilation. Please recompile with '"
+ << setting << "'" << std::endl;
+
+ return simple_numeric_source::factory(l, name, &NaN);
+ }
+ }
+
+ double data_source_base::get_number() const
+ { return NaN; }
+
+ std::string data_source_base::get_text() const
+ {
+ std::ostringstream s;
+ s << get_number();
+ return s.str();
+ }
+
+ template
+ std::shared_ptr
+ simple_numeric_source::factory(lua::state &l, const std::string &name, const T *source)
+ {
+ l.pop();
+ return std::shared_ptr(new simple_numeric_source(name, source));
+ }
+
+ register_data_source::register_data_source(const std::string &name,
+ const data_source_factory &factory_func)
+ { register_data_source_(name, factory_func); }
+
+ register_disabled_data_source::register_disabled_data_source(const std::string &name,
+ const std::string &setting)
+ {
+ register_data_source_(name,
+ std::bind(disabled_source_factory,
+ std::placeholders::_1, std::placeholders::_2, setting)
+ );
+ }
+}
diff --git a/src/data-source.hh b/src/data-source.hh
new file mode 100644
index 00000000..f11806eb
--- /dev/null
+++ b/src/data-source.hh
@@ -0,0 +1,107 @@
+/* -*- mode: c++; c-basic-offset: 4; tab-width: 4; indent-tabs-mode: t -*-
+ * vim: ts=4 sw=4 noet ai cindent syntax=cpp
+ *
+ * Conky, a system monitor, based on torsmo
+ *
+ * Please see COPYING for details
+ *
+ * Copyright (C) 2010 Pavel Labath et al.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see .
+ *
+ */
+
+#ifndef DATA_SOURCE_HH
+#define DATA_SOURCE_HH
+
+#include
+#include
+#include
+#include
+
+#include "luamm.hh"
+
+namespace conky {
+
+ class data_source_base;
+
+ /*
+ * Recieves a lua table on the stack and the name the object was registered with. It should
+ * pop the table after consuming it and return the data source.
+ */
+ typedef std::function (lua::state &l, const std::string &name)> data_source_factory;
+
+ /*
+ * A base class for all data sources.
+ * API consists of two functions:
+ * - get_number should return numeric representation of the data (if available). This can
+ * then be used when drawing graphs, bars, ... The default implementation returns NaN.
+ * - get_text should return textual representation of the data. This is used when simple
+ * displaying the value of the data source. The default implementation converts
+ * get_number() to a string, but you can override to return anything (e.g. add units)
+ */
+ class data_source_base {
+ public:
+ const std::string name;
+
+ data_source_base(const std::string &name_)
+ : name(name_)
+ {}
+
+ virtual ~data_source_base() {}
+ virtual double get_number() const;
+ virtual std::string get_text() const;
+ };
+
+ /*
+ * A simple data source that returns the value of some variable.
+ * It ignores the lua table, but one can create a wrapper for the factory function that uses
+ * data in the table to decide which variable to return.
+ */
+ template
+ class simple_numeric_source: public data_source_base {
+ static_assert(std::is_convertible::value, "T must be convertible to double");
+
+ const T *source;
+
+ simple_numeric_source(const std::string &name_, const T *source_)
+ : data_source_base(name_), source(source_)
+ {}
+ public:
+ static std::shared_ptr
+ factory(lua::state &l, const std::string &name, const T *source);
+
+ virtual double get_number() const
+ { return *source; }
+ };
+
+ /*
+ * Declaring an object of this type at global scope will register a data source with the give
+ * name and factory function.
+ */
+ class register_data_source {
+ public:
+ register_data_source(const std::string &name, const data_source_factory &factory_func);
+ };
+
+ /*
+ * Use this to declare a data source that has been disabled during compilation. We can then
+ * print a nice error message telling the used which setting to enable.
+ */
+ class register_disabled_data_source {
+ public:
+ register_disabled_data_source(const std::string &name, const std::string &setting);
+ };
+}
+
+#endif /* DATA_SOURCE_HH */