Initial stubbing of display backends

Hopefully this will lead the way to adding support for things like
Wayland and Haiku graphics, cf. brndnmtthws#56.

We define a display_output_base class that display backends
can derive from to implement display-specific calls.

src/CMakeLists.txt

@@ -68,6 +68,11 @@ set(conky_sources
   user.cc user.h
   luamm.cc luamm.hh
   data-source.cc data-source.hh
+  display-output.cc display-output.hh
+  display-console.cc display-console.hh
+  display-ncurses.cc display-ncurses.hh
+  display-http.cc display-http.hh
+  display-x11.cc display-x11.hh
   lua-config.cc lua-config.hh
   setting.cc setting.hh
   llua.cc llua.h

src/conky.cc

@@ -118,6 +118,7 @@
 
 #include "lua-config.hh"
 #include "setting.hh"
+#include "display-output.hh"
 
 /* check for OS and include appropriate headers */
 #if defined(__linux__)
@@ -3039,6 +3040,10 @@ void initialisation(int argc, char **argv) {
   tmpstring2 = static_cast<char *>(malloc(text_buffer_size.get(*state)));
   memset(tmpstring2, 0, text_buffer_size.get(*state));
 
+  if (!conky::initialize_display_outputs()) {
+    CRIT_ERR(nullptr, nullptr, "initialize_display_outputs() failed.");
+  }
+
 #ifdef BUILD_X11
   X11_create_window();
 #endif /* BUILD_X11 */
@@ -3169,6 +3174,8 @@ int main(int argc, char **argv) {
     return EXIT_FAILURE;
   }
 
+  conky::shutdown_display_outputs();
+
 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
   kvm_close(kd);
 #endif

src/display-console.cc

@@ -0,0 +1,67 @@
+/*
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <config.h>
+
+#include "conky.h"
+#include "display-console.hh"
+
+#include <iostream>
+#include <sstream>
+#include <unordered_map>
+
+namespace conky {
+namespace {
+
+conky::display_output_console console_output("console");
+
+}  // namespace
+
+namespace priv {
+
+
+}  // namespace priv
+
+display_output_console::display_output_console(const std::string &name_)
+    : display_output_base(name_) {
+  // lowest priority, it's a fallback
+  priority = 0;
+}
+
+bool display_output_console::detect() {
+  if (out_to_stdout.get(*state) || out_to_stderr.get(*state)) {
+    std::cerr << "Display output '" << name << "' enabled in config." << std::endl;
+    return true;
+  }
+  return false;
+}
+
+bool display_output_console::initialize() {
+  return true;
+}
+
+bool display_output_console::shutdown() {
+  return true;
+}
+
+}  // namespace conky
+

src/display-console.hh

@@ -0,0 +1,57 @@
+/*
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef DISPLAY_CONSOLE_HH
+#define DISPLAY_CONSOLE_HH
+
+#include <limits>
+#include <string>
+#include <type_traits>
+
+#include "luamm.hh"
+#include "display-output.hh"
+
+namespace conky {
+
+/*
+ * A base class for console display output.
+ */
+class display_output_console : public display_output_base {
+
+ public:
+
+  explicit display_output_console(const std::string &name_);
+
+  virtual ~display_output_console() {}
+
+  // check if available and enabled in settings
+  virtual bool detect();
+  // connect to DISPLAY and other stuff
+  virtual bool initialize();
+  virtual bool shutdown();
+
+  // console-specific
+};
+
+}  // namespace conky
+
+#endif /* DISPLAY_CONSOLE_HH */

src/display-http.cc

@@ -0,0 +1,76 @@
+/*
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <config.h>
+
+#include "conky.h"
+#include "display-http.hh"
+
+#include <iostream>
+#include <sstream>
+#include <unordered_map>
+
+namespace conky {
+namespace {
+
+#ifdef BUILD_HTTP
+conky::display_output_http http_output;
+#else
+conky::disabled_display_output http_output_disabled("http", "BUILD_HTTP");
+#endif
+
+}  // namespace
+
+namespace priv {
+
+
+}  // namespace priv
+
+#ifdef BUILD_HTTP
+
+display_output_http::display_output_http()
+    : display_output_base("http") {
+  priority = 1;
+}
+
+bool display_output_http::detect() {
+  /* TODO:
+  if (out_to_http.get(*state)) {
+    std::cerr << "Display output '" << name << "' enabled in config." << std::endl;
+    return true;
+  }
+  */
+  return false;
+}
+
+bool display_output_http::initialize() {
+  return false;
+}
+
+bool display_output_http::shutdown() {
+  return false;
+}
+
+#endif
+
+}  // namespace conky
+

src/display-http.hh

@@ -0,0 +1,57 @@
+/*
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef DISPLAY_HTTP_HH
+#define DISPLAY_HTTP_HH
+
+#include <limits>
+#include <string>
+#include <type_traits>
+
+#include "luamm.hh"
+#include "display-output.hh"
+
+namespace conky {
+
+/*
+ * A base class for HTTP display output.
+ */
+class display_output_http : public display_output_base {
+
+ public:
+
+  explicit display_output_http();
+
+  virtual ~display_output_http() {}
+
+  // check if available and enabled in settings
+  virtual bool detect();
+  // connect to DISPLAY and other stuff
+  virtual bool initialize();
+  virtual bool shutdown();
+
+  // HTTP-specific
+};
+
+}  // namespace conky
+
+#endif /* DISPLAY_HTTP_HH */

src/display-ncurses.cc

@@ -0,0 +1,75 @@
+/*
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <config.h>
+
+#include "conky.h"
+#include "nc.h"
+#include "display-ncurses.hh"
+
+#include <iostream>
+#include <sstream>
+#include <unordered_map>
+
+namespace conky {
+namespace {
+
+#ifdef BUILD_NCURSES
+conky::display_output_ncurses ncurses_output;
+#else
+conky::disabled_display_output ncurses_output_disabled("ncurses", "BUILD_NCURSES");
+#endif
+
+}  // namespace
+
+namespace priv {
+
+
+}  // namespace priv
+
+#ifdef BUILD_NCURSES
+
+display_output_ncurses::display_output_ncurses()
+    : display_output_console("ncurses") {
+  priority = 1;
+}
+
+bool display_output_ncurses::detect() {
+  if (out_to_ncurses.get(*state)) {
+    std::cerr << "Display output '" << name << "' enabled in config." << std::endl;
+    return true;
+  }
+  return false;
+}
+
+bool display_output_ncurses::initialize() {
+  return false;
+}
+
+bool display_output_ncurses::shutdown() {
+  return false;
+}
+
+#endif /* BUILD_NCURSES */
+
+}  // namespace conky
+