More robust platform definition support.

The idea is that someday it will be possible to just concatenate the entire
set of source files into a single giant source file, for systems that
want to work this way.  As a result, the build system now compiles every
file, although some of them will not have any definitions.

1 files changed, 154 insertions, 0 deletions

diff --git a/src/platform/posix/posix_clock.c b/src/platform/posix/posix_clock.c
new file mode 100644
index 00000000..c772263c
--- /dev/null
+++ b/src/platform/posix/posix_clock.c
@@ -0,0 +1,154 @@
+/*
+ * Copyright 2016 Garrett D'Amore <garrett@damore.org>
+ *
+ * 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.
+ */
+
+/*
+ * This is more of a direct #include of a .c rather than .h file.
+ * But having it be a .h makes compiler rules work out properly.  Do
+ * not include this more than once into your program, or you will
+ * get multiple symbols defined.
+ */
+
+/*
+ * POSIX clock stuff.
+ */
+#include "core/nng_impl.h"
+
+#ifdef PLATFORM_POSIX_CLOCK
+
+#include <time.h>
+#include <errno.h>
+#include <string.h>
+
+#ifndef	NNG_USE_GETTIMEOFDAY
+
+/*
+ * Use POSIX realtime stuff.
+ */
+
+uint64_t
+nni_clock(void)
+{
+	struct timespec	ts;
+	uint64_t	usec;
+
+	if (clock_gettime(NNG_USE_CLOCKID, &ts) != 0) {
+		/* This should never ever occur. */
+		nni_panic("clock_gettime failed: %s", strerror(errno));
+	}
+
+	usec = ts.tv_sec;
+	usec *= 1000000;
+	usec += (ts.tv_nsec / 1000);
+	return (usec);
+}
+
+
+void
+nni_usleep(uint64_t usec)
+{
+	struct timespec ts;
+
+	ts.tv_sec = usec / 1000000;
+	ts.tv_nsec = (usec % 1000000) * 1000;
+
+	/* Do this in a loop, so that interrupts don't actually wake us. */
+	while (ts.tv_sec || ts.tv_nsec) {
+		(void) nanosleep(&ts, &ts);
+	}
+}
+
+#else	/* NNG_USE_GETTIMEOFDAY */
+
+/*
+ * If you're here, its because you don't have a modern clock_gettime with
+ * monotonic clocks, or the necessary pthread_condattr_settclock().  In
+ * this case, you should be advised that *bad* things can happen if your
+ * system clock changes time while programs using this library are running.
+ * (Basically, timeouts can take longer or shorter, leading to either hangs
+ * or apparent spurious errors.  Eventually it should all sort itself out,
+ * but if you change the clock by a large amount you might wonder what the
+ * heck is happening until it does.)
+ */
+
+#include <pthread.h>
+#include <sys/time.h>
+
+uint64_t
+nni_clock(void)
+{
+	uint64_t usec;
+
+	struct timeval tv;
+	if (gettimeofday(&tv, NULL) != 0) {
+		nni_panic("gettimeofday failed: %s", strerror(errno));
+	}
+
+	usec = tv.tv_sec;
+	usec *= 1000000;
+	usec += tv.tv_usec;
+	return (usec);
+}
+
+void
+nni_usleep(uint64_t usec)
+{
+	/*
+	 * So probably there is no nanosleep.  We could in theory use
+	 * pthread condition variables, but that means doing memory
+	 * allocation, or forcing the use of pthreads where the platform
+	 * might be preferring the use of another threading package.
+	 * Additionally, use of pthreads means that we cannot use
+	 * relative times in a clock_settime safe manner.
+	 * So we can use poll() instead, which is rather coarse, but
+	 * pretty much guaranteed to work.
+	 */
+	struct pollfd pfd;
+	uint64_t now;
+	uint64_t expire;
+
+	/*
+	 * Possibly we could pass NULL instead of pfd, but passing a valid
+	 * pointer ensures that if the system dereferences the pointer it
+	 * won't come back with EFAULT.
+	 */
+	pfd.fd = -1;
+	pfd.events = 0;
+
+ 	now = nni_clock();
+	expire = now + usec;
+
+	while (now < expire) {
+		/*
+		 * In theory we could round up to a whole number of msec,
+		 * but under the covers poll already does some rounding up,
+		 * and the loop above guarantees that we will not bail out
+		 * early.  So this gives us a better chance to avoid adding
+		 * nearly an extra unneeded millisecond to the wait.
+		 */
+		(void) poll(&pfd, 0, (int)((expire - now) / 1000));
+ 		now = nni_clock();
+	}
+}
+
+#endif	/* NNG_USE_GETTIMEOFDAY */
+
+#endif	/* PLATFORM_POSIX_CLOCK */