New untested libusb-to-libev bridge

server/Makefile

@@ -11,6 +11,7 @@ TARGET := fcserver
 CPP_FILES = \
 	main.cpp \
 	opcsink.cpp \
+	libusbev.cpp \
 	fcserver.cpp
 
 # CPPFLAGS = compiler options for C and C++

server/fcserver.cpp

@@ -34,7 +34,8 @@ FCServer::FCServer(rapidjson::Document &config)
 	  mDevices(config["devices"]),
 	  mVerbose(config["verbose"].IsTrue()),
 	  mListenAddr(0),
-	  mOPCSink(opcCallback, this, mVerbose)
+	  mOPCSink(opcCallback, this, mVerbose),
+	  mUSB(0)
 {
 	/*
 	 * Parse the listen [host, port] list.
@@ -81,6 +82,17 @@ FCServer::~FCServer()
 void FCServer::start(struct ev_loop *loop)
 {
 	mOPCSink.start(loop, mListenAddr);
+	startUSB(loop);
+}
+
+void FCServer::startUSB(struct ev_loop *loop)
+{	
+	if (libusb_init(&mUSB)) {
+		std::clog << "Error initializing USB library!\n";
+		return;
+	}
+
+	mUSBEvent.init(mUSB, loop);
 }
 
 void FCServer::opcCallback(OPCSink::Message &msg, void *context)

server/fcserver.h

@@ -24,6 +24,8 @@
 #pragma once
 #include "rapidjson/document.h"
 #include "opcsink.h"
+#include "libusbev.h"
+#include <libusb.h>
 #include <sstream>
 #include <ev.h>
 #include <netinet/in.h>
@@ -53,5 +55,9 @@ private:
     struct addrinfo *mListenAddr;
     OPCSink mOPCSink;
 
+    libusb_context *mUSB;
+    LibUSBEventBridge mUSBEvent;
+
     static void opcCallback(OPCSink::Message &msg, void *context);
+    void startUSB(struct ev_loop *loop);
 };

server/libusbev.cpp

+/*
+ * Glue for using libusb with libev
+ * 
+ * Copyright (c) 2013 Micah Elizabeth Scott
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include "libusbev.h"
+#include "util.h"
+#include <stdlib.h>
+#include <poll.h>
+
+
+void LibUSBEventBridge::cbEvent(struct ev_loop *loop, ev_io *io, int revents)
+{
+	Watcher *w = container_of(io, Watcher, io);
+	LibUSBEventBridge *self = w->self;
+
+	// Handle pending USB events without blocking
+	struct timeval tvZero = { 0, 0 };
+	libusb_handle_events_timeout(self->mCtx, &tvZero);
+}
+
+void LibUSBEventBridge::cbAdded(int fd, short events, void *user_data)
+{
+	LibUSBEventBridge *self = static_cast<LibUSBEventBridge*>(user_data);
+	Watcher *w = new Watcher();
+
+	ev_io_init(&w->io, cbEvent, fd,
+		((events & POLLIN) ? EV_READ : 0) |
+		((events & POLLOUT) ? EV_WRITE : 0));
+
+	self->mWatchers[fd] = w;
+	ev_io_start(self->mLoop, &w->io);
+}
+
+void LibUSBEventBridge::cbRemoved(int fd, void *user_data)
+{
+	LibUSBEventBridge *self = static_cast<LibUSBEventBridge*>(user_data);
+	Watcher *w = self->mWatchers[fd];
+
+	ev_io_stop(self->mLoop, &w->io);
+	self->mWatchers.erase(fd);
+}
+
+void LibUSBEventBridge::init(struct libusb_context *ctx, struct ev_loop *loop)
+{
+	mCtx = ctx;
+	mLoop = loop;
+
+	// Handle FDs that are already registered
+	const struct libusb_pollfd **fds = libusb_get_pollfds(ctx);
+	for (const struct libusb_pollfd **i = fds; *i; ++i) {
+		cbAdded((*i)->fd, (*i)->events, this);
+	}
+	free(fds);
+
+	// Get notified when future callbacks are added
+	libusb_set_pollfd_notifiers(ctx, cbAdded, cbRemoved, this);
+}

server/libusbev.h

+/*
+ * Glue for using libusb with libev
+ * 
+ * Copyright (c) 2013 Micah Elizabeth Scott
+ * 
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ * 
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#pragma once
+#include <ev.h>
+#include <libusb.h>
+#include <map>
+
+class LibUSBEventBridge
+{
+public:
+
+    // Call after libusb_init
+    void init(struct libusb_context *ctx, struct ev_loop *loop);
+
+private:
+    struct Watcher {
+        ev_io io;
+        LibUSBEventBridge *self;
+    };
+
+    struct libusb_context *mCtx;
+    struct ev_loop *mLoop;
+    std::map<int, Watcher*> mWatchers;
+
+    static void cbEvent(struct ev_loop *loop, ev_io *io, int revents);
+    static void cbAdded(int fd, short events, void *user_data);
+    static void cbRemoved(int fd, void *user_data);
+};

server/util.h

@@ -23,8 +23,12 @@
 
 #pragma once
 
-#define offsetof(st, m) __builtin_offsetof(st, m)
+#ifndef offsetof
+#  define offsetof(st, m) __builtin_offsetof(st, m)
+#endif
 
-#define container_of(ptr, type, member) ({ \
-    const typeof( ((type *)0)->member ) *__mptr = (ptr); \
-    (type *)( (char *)__mptr - offsetof(type,member) );})
+#ifndef container_of
+#  define container_of(ptr, type, member) ({ \
+     const typeof( ((type *)0)->member ) *__mptr = (ptr); \
+     (type *)( (char *)__mptr - offsetof(type,member) );})
+#endif