From 7262f1e7e9ea88a021c14de9dc06ebe76112afd7 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 19 Sep 2016 23:39:14 +0300
Subject: [PATCH] Enumerate available game controllers

Assign indices from zero to N-1 internally.  This makes it easier for
applications to use game controllers as the first available controller
will always have index zero.
---
 source/input/gamecontroller.cpp              | 18 ++++++++++++++
 source/input/gamecontroller.h                |  6 +++++
 source/input/generic/gamecontroller.cpp      |  6 +++++
 source/input/linux/gamecontroller.cpp        | 26 +++++++++++++++++++-
 source/input/linux/gamecontroller_platform.h |  2 ++
 5 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 source/input/gamecontroller.cpp

diff --git a/source/input/gamecontroller.cpp b/source/input/gamecontroller.cpp
new file mode 100644
index 0000000..1ad8757
--- /dev/null
+++ b/source/input/gamecontroller.cpp
@@ -0,0 +1,18 @@
+#include "gamecontroller.h"
+
+namespace Msp {
+namespace Input {
+
+bool GameController::detect_done = false;
+unsigned GameController::n_detected_controllers = 0;
+
+bool GameController::is_available(unsigned index)
+{
+	if(!detect_done)
+		detect();
+
+	return index<n_detected_controllers;
+}
+
+} // namespace Input
+} // namespace Msp
diff --git a/source/input/gamecontroller.h b/source/input/gamecontroller.h
index 84c50b5..863f66f 100644
--- a/source/input/gamecontroller.h
+++ b/source/input/gamecontroller.h
@@ -16,10 +16,16 @@ private:
 	Private *priv;
 	IO::EventDispatcher *event_disp;
 
+	static bool detect_done;
+	static unsigned n_detected_controllers;
+
 public:
 	GameController(unsigned);
 	virtual ~GameController();
 
+	static unsigned detect();
+	static bool is_available(unsigned = 0);
+
 	void use_event_dispatcher(IO::EventDispatcher *);
 
 	void tick();
diff --git a/source/input/generic/gamecontroller.cpp b/source/input/generic/gamecontroller.cpp
index 419c678..9ab6738 100644
--- a/source/input/generic/gamecontroller.cpp
+++ b/source/input/generic/gamecontroller.cpp
@@ -15,6 +15,12 @@ GameController::~GameController()
 {
 }
 
+unsigned GameController::detect()
+{
+	detect_done = true;
+	return 0;
+}
+
 void GameController::use_event_dispatcher(IO::EventDispatcher *)
 {
 }
diff --git a/source/input/linux/gamecontroller.cpp b/source/input/linux/gamecontroller.cpp
index 2fc624e..c00379d 100644
--- a/source/input/linux/gamecontroller.cpp
+++ b/source/input/linux/gamecontroller.cpp
@@ -1,6 +1,7 @@
 #include <fcntl.h>
 #include <linux/joystick.h>
 #include <msp/core/systemerror.h>
+#include <msp/fs/dir.h>
 #include <msp/io/handle_private.h>
 #include <msp/strings/format.h>
 #include "gamecontroller.h"
@@ -11,10 +12,17 @@ using namespace std;
 namespace Msp {
 namespace Input {
 
+vector<string> GameController::Private::detected_controllers;
+
 GameController::GameController(unsigned index):
 	event_disp(0)
 {
-	JsDevice *device = new JsDevice(format("/dev/input/js%d", index));
+	if(!detect_done)
+		detect();
+	if(index>=Private::detected_controllers.size())
+		throw device_not_available(format("GameController(%d)", index));
+
+	JsDevice *device = new JsDevice(Private::detected_controllers[index]);
 
 	priv = new Private;
 	priv->dev = device;
@@ -29,6 +37,22 @@ GameController::~GameController()
 	delete priv;
 }
 
+unsigned GameController::detect()
+{
+	Private::detected_controllers.clear();
+
+	FS::Path dev_input = "/dev/input";
+	list<string> devices = FS::list_filtered(dev_input, "^js[0-9]+");
+	for(list<string>::const_iterator i=devices.begin(); i!=devices.end(); ++i)
+		// TODO check permissions
+		Private::detected_controllers.push_back((dev_input / *i).str());
+
+	detect_done = true;
+	n_detected_controllers = Private::detected_controllers.size();
+
+	return Private::detected_controllers.size();
+}
+
 void GameController::use_event_dispatcher(IO::EventDispatcher *ed)
 {
 	if(event_disp)
diff --git a/source/input/linux/gamecontroller_platform.h b/source/input/linux/gamecontroller_platform.h
index cd63839..2951076 100644
--- a/source/input/linux/gamecontroller_platform.h
+++ b/source/input/linux/gamecontroller_platform.h
@@ -30,6 +30,8 @@ public:
 struct GameController::Private
 {
 	JsDevice *dev;
+
+	static std::vector<std::string> detected_controllers;
 };
 
 } // namespace Input
-- 
2.43.0