[glib] Add a UNIX fd source

[Ryan Lortie <ryanl src gnome org>]

commit 6d1a6636090b498d43354d5503ac39fb10ac908c
Author: Ryan Lortie <desrt desrt ca>
Date:   Mon Jan 14 14:47:16 2013 -0500

    Add a UNIX fd source
    
    https://bugzilla.gnome.org/show_bug.cgi?id=658020

 docs/reference/glib/glib-sections.txt |   10 ++-
 glib/glib-unix.c                      |  139 +++++++++++++++++++++++++++++++++
 glib/glib-unix.h                      |   33 ++++++++
 glib/glib.symbols                     |    3 +
 4 files changed, 184 insertions(+), 1 deletions(-)
---
diff --git a/docs/reference/glib/glib-sections.txt b/docs/reference/glib/glib-sections.txt
index d5a70b2..927d4f7 100644
--- a/docs/reference/glib/glib-sections.txt
+++ b/docs/reference/glib/glib-sections.txt
@@ -2007,10 +2007,18 @@ g_win32_ftruncate
 <FILE>gunix</FILE>
 G_UNIX_ERROR
 g_unix_open_pipe
+g_unix_set_fd_nonblocking
+
+<SUBSECTION>
 g_unix_signal_add
 g_unix_signal_add_full
 g_unix_signal_source_new
-g_unix_set_fd_nonblocking
+
+<SUBSECTION>
+GUnixFdSourceFunc
+g_unix_fd_add
+g_unix_fd_add_full
+g_unix_fd_source_new
 
 <SUBSECTION Private>
 g_unix_error_quark
diff --git a/glib/glib-unix.c b/glib/glib-unix.c
index 9cc2716..0f12cc4 100644
--- a/glib/glib-unix.c
+++ b/glib/glib-unix.c
@@ -284,3 +284,142 @@ g_unix_signal_add (int         signum,
 {
   return g_unix_signal_add_full (G_PRIORITY_DEFAULT, signum, handler, user_data, NULL);
 }
+
+typedef struct
+{
+  GSource source;
+
+  gint     fd;
+  gpointer tag;
+} GUnixFDSource;
+
+static gboolean
+g_unix_fd_source_dispatch (GSource     *source,
+                           GSourceFunc  callback,
+                           gpointer     user_data)
+{
+  GUnixFDSource *fd_source = (GUnixFDSource *) source;
+  GUnixFDSourceFunc func = (GUnixFDSourceFunc) callback;
+
+  if (!callback)
+    {
+      g_warning ("GUnixFDSource dispatched without callback\n"
+                 "You must call g_source_set_callback().");
+      return FALSE;
+    }
+
+  return (* func) (fd_source->fd, g_source_query_unix_fd (source, fd_source->tag), user_data);
+}
+
+
+/**
+ * g_unix_fd_source_new:
+ * @fd: a file descriptor
+ * @condition: IO conditions to watch for on @fd
+ *
+ * Creates a #GSource to watch for a particular IO condition on a file
+ * descriptor.
+ *
+ * The source will never close the fd -- you must do it yourself.
+ *
+ * Returns: the newly created #GSource
+ *
+ * Since: 2.36
+ **/
+GSource *
+g_unix_fd_source_new (gint         fd,
+                      GIOCondition condition)
+{
+  static GSourceFuncs source_funcs = {
+    NULL, NULL, g_unix_fd_source_dispatch, NULL
+  };
+  GUnixFDSource *fd_source;
+  GSource *source;
+
+  source = g_source_new (&source_funcs, sizeof (GUnixFDSource));
+  fd_source = (GUnixFDSource *) source;
+
+  fd_source->fd = fd;
+  fd_source->tag = g_source_add_unix_fd (source, fd, condition);
+
+  return source;
+}
+
+/**
+ * g_unix_fd_add_full:
+ * @priority: the priority of the source
+ * @fd: a file descriptor
+ * @condition: IO conditions to watch for on @fd
+ * @function: a #GUnixFDSourceFunc
+ * @user_data: data to pass to @function
+ * @notify: function to call when the idle is removed, or %NULL
+ *
+ * Sets a function to be called when the IO condition, as specified by
+ * @condition becomes true for @fd.
+ *
+ * This is the same as g_unix_fd_add(), except that it allows you to
+ * specify a non-default priority and a provide a #GDestroyNotify for
+ * @user_data.
+ *
+ * Returns: the ID (greater than 0) of the event source
+ *
+ * Since: 2.36
+ **/
+guint
+g_unix_fd_add_full (gint              priority,
+                    gint              fd,
+                    GIOCondition      condition,
+                    GUnixFDSourceFunc function,
+                    gpointer          user_data,
+                    GDestroyNotify    notify)
+{
+  GSource *source;
+  guint id;
+
+  g_return_val_if_fail (function != NULL, 0);
+
+  source = g_unix_fd_source_new (fd, condition);
+
+  if (priority != G_PRIORITY_DEFAULT)
+    g_source_set_priority (source, priority);
+
+  g_source_set_callback (source, (GSourceFunc) function, user_data, notify);
+  id = g_source_attach (source, NULL);
+  g_source_unref (source);
+
+  return id;
+}
+
+/**
+ * g_unix_fd_add:
+ * @fd: a file descriptor
+ * @condition: IO conditions to watch for on @fd
+ * @function: a #GPollFDFunc
+ * @user_data: data to pass to @function
+ *
+ * Sets a function to be called when the IO condition, as specified by
+ * @condition becomes true for @fd.
+ *
+ * @function will be called when the specified IO condition becomes
+ * %TRUE.  The function is expected to clear whatever event caused the
+ * IO condition to become true and return %TRUE in order to be notified
+ * when it happens again.  If @function returns %FALSE then the watch
+ * will be cancelled.
+ *
+ * The return value of this function can be passed to g_source_remove()
+ * to cancel the watch at any time that it exists.
+ *
+ * The source will never close the fd -- you must do it yourself.
+ *
+ * Returns: the ID (greater than 0) of the event source
+ *
+ * Since: 2.36
+ **/
+guint
+g_unix_fd_add (gint              fd,
+               GIOCondition      condition,
+               GUnixFDSourceFunc function,
+               gpointer          user_data)
+{
+  return g_unix_fd_add_full (G_PRIORITY_DEFAULT, fd, condition, function, user_data, NULL);
+}
diff --git a/glib/glib-unix.h b/glib/glib-unix.h
index c04f66f..66ccf74 100644
--- a/glib/glib-unix.h
+++ b/glib/glib-unix.h
@@ -85,6 +85,39 @@ guint    g_unix_signal_add         (gint        signum,
                                     GSourceFunc handler,
                                     gpointer    user_data);
 
+/**
+ * GUnixFDSourceFunc:
+ * @fd: the fd that triggered the event
+ * @condition: the IO conditions reported on @fd
+ * @user_data: user data passed to g_unix_fd_add()
+ *
+ * The type of functions to be called when a UNIX fd watch source
+ * triggers.
+ *
+ * Returns: %FALSE if the source should be removed
+ **/
+typedef gboolean (*GUnixFDSourceFunc) (gint         fd,
+                                       GIOCondition condition,
+                                       gpointer     user_data);
+
+GLIB_AVAILABLE_IN_2_36
+GSource *g_unix_fd_source_new      (gint         fd,
+                                    GIOCondition condition);
+
+GLIB_AVAILABLE_IN_2_36
+guint    g_unix_fd_add_full        (gint              priority,
+                                    gint              fd,
+                                    GIOCondition      condition,
+                                    GUnixFDSourceFunc function,
+                                    gpointer          user_data,
+                                    GDestroyNotify    notify);
+
+GLIB_AVAILABLE_IN_2_36
+guint    g_unix_fd_add             (gint              fd,
+                                    GIOCondition      condition,
+                                    GUnixFDSourceFunc function,
+                                    gpointer          user_data);
+
 G_END_DECLS
 
 #endif  /* __G_UNIX_H__ */
diff --git a/glib/glib.symbols b/glib/glib.symbols
index b317e7c..28ddde5 100644
--- a/glib/glib.symbols
+++ b/glib/glib.symbols
@@ -1641,6 +1641,9 @@ g_unix_set_fd_nonblocking
 g_unix_signal_add
 g_unix_signal_add_full
 g_unix_signal_source_new
+g_unix_fd_add
+g_unix_fd_add_full
+g_unix_fd_source_new
 #endif
 g_ascii_table
 g_utf8_skip