From 29bec0c0e0658b51f11ea38c04df0e7aa514572c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C5=99emysl=20Janouch?= <p.janouch@gmail.com>
Date: Sun, 26 Oct 2014 18:57:28 +0100
Subject: Lay down some server-client foundations

---
 utils.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)

(limited to 'utils.c')

diff --git a/utils.c b/utils.c
index 27d9e8d..e1580e0 100644
--- a/utils.c
+++ b/utils.c
@@ -34,6 +34,9 @@
 
 #define N_ELEMENTS(a) (sizeof (a) / sizeof ((a)[0]))
 
+#define BLOCK_START  do {
+#define BLOCK_END    } while (0)
+
 // --- Safe memory management --------------------------------------------------
 
 // When a memory allocation fails and we need the memory, we're usually pretty
@@ -76,6 +79,31 @@ xrealloc (void *o, size_t n)
 	return p;
 }
 
+// --- Double-linked list helpers ----------------------------------------------
+
+#define LIST_HEADER(type)                                                      \
+	type *next;                                                                \
+	type *prev;
+
+#define LIST_PREPEND(head, link)                                               \
+	BLOCK_START                                                                \
+		(link)->prev = NULL;                                                   \
+		(link)->next = (head);                                                 \
+		if ((link)->next)                                                      \
+			(link)->next->prev = (link);                                       \
+		(head) = (link);                                                       \
+	BLOCK_END
+
+#define LIST_UNLINK(head, link)                                                \
+	BLOCK_START                                                                \
+		if ((link)->prev)                                                      \
+			(link)->prev->next = (link)->next;                                 \
+		else                                                                   \
+			(head) = (link)->next;                                             \
+		if ((link)->next)                                                      \
+			(link)->next->prev = (link)->prev;                                 \
+	BLOCK_END
+
 // --- Dynamically allocated strings -------------------------------------------
 
 // Basically a string builder to abstract away manual memory management.
@@ -190,6 +218,49 @@ str_append_printf (struct str *self, const char *fmt, ...)
 
 // --- Utilities ---------------------------------------------------------------
 
+static bool
+set_blocking (int fd, bool blocking)
+{
+	int flags = fcntl (fd, F_GETFL);
+	bool prev = !(flags & O_NONBLOCK);
+	if (blocking)
+		flags &= ~O_NONBLOCK;
+	else
+		flags |=  O_NONBLOCK;
+	return prev;
+}
+
+static void
+xclose (int fd)
+{
+	while (close (fd) == -1)
+		if (errno != EINTR)
+			break;
+}
+
+static char *xstrdup_printf (const char *, ...) ATTRIBUTE_PRINTF (1, 2);
+
+static char *
+xstrdup_printf (const char *format, ...)
+{
+	va_list ap;
+	struct str tmp;
+	str_init (&tmp);
+	va_start (ap, format);
+	str_append_vprintf (&tmp, format, ap);
+	va_end (ap);
+	return str_steal (&tmp);
+}
+
+static char *
+format_host_port_pair (const char *host, const char *port)
+{
+	// IPv6 addresses mess with the "colon notation"; let's go with RFC 2732
+	if (strchr (host, ':'))
+		return xstrdup_printf ("[%s]:%s", host, port);
+	return xstrdup_printf ("%s:%s", host, port);
+}
+
 static bool
 xstrtoul (unsigned long *out, const char *s, int base)
 {
-- 
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