[libgsystem] gsystem-errors.h: Add gs_set_error_from_errno()

[Colin Walters <walters src gnome org>]

commit ed106741f7a0596dc8b960b31fdae671d31d666d
Author: Colin Walters <walters verbum org>
Date:   Wed Dec 17 22:36:57 2014 -0500

    gsystem-errors.h: Add gs_set_error_from_errno()
    
    This is a long overdue move of this function to public API.

 Makefile-libgsystem.am |    2 +
 src/gsystem-errors.c   |   75 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/gsystem-errors.h   |   37 +++++++++++++++++++++++
 src/libgsystem.h       |    1 +
 4 files changed, 115 insertions(+), 0 deletions(-)
---
diff --git a/Makefile-libgsystem.am b/Makefile-libgsystem.am
index b75d517..676a230 100644
--- a/Makefile-libgsystem.am
+++ b/Makefile-libgsystem.am
@@ -25,6 +25,7 @@ libgsystemheader_HEADERS = \
        src/gsystem-glib-compat.h \
        src/gsystem-shutil.h \
        src/gsystem-log.h \
+       src/gsystem-errors.h \
        src/gsystem-subprocess-context.h \
        src/gsystem-subprocess.h \
        src/libgsystem.h \
@@ -35,6 +36,7 @@ libgsystem_la_SOURCES = \
        src/gsystem-console.c \
        src/gsystem-file-utils.c \
        src/gsystem-shutil.c \
+       src/gsystem-errors.c \
        src/gsystem-log.c \
        src/gsystem-subprocess-context-private.h \
        src/gsystem-subprocess-context.c \
diff --git a/src/gsystem-errors.c b/src/gsystem-errors.c
new file mode 100644
index 0000000..af7fd09
--- /dev/null
+++ b/src/gsystem-errors.c
@@ -0,0 +1,75 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
+ *
+ * Copyright (C) 2014 Colin Walters <walters verbum org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "config.h"
+
+#include "gsystem-errors.h"
+#include "gsystem-local-alloc.h"
+#include <glib-unix.h>
+
+/**
+ * gs_set_error_from_errno:
+ * @error: (allow-none): Error
+ * @saved_errno: errno value
+ * 
+ * Set @error to an error with domain %G_IO_ERROR, and code based on
+ * the value of @saved_errno.  The error message is set using a
+ * literal return from g_strerror().
+ */
+void
+gs_set_error_from_errno (GError **error, gint saved_errno)
+{
+  g_set_error_literal (error,
+                       G_IO_ERROR,
+                       g_io_error_from_errno (saved_errno),
+                       g_strerror (saved_errno));
+  errno = saved_errno;
+}
+
+/**
+ * gs_set_prefix_error_from_errno:
+ * @error: (allow-none): Error
+ * @saved_errno: errno value
+ * @format: Format string for printf
+ * 
+ * Set @error to an error with domain %G_IO_ERROR, and code based on
+ * the value of @saved_errno.  The error message is prefixed with the
+ * result of @format, a colon and space, then the result of
+ * g_strerror().
+ */
+void
+gs_set_prefix_error_from_errno (GError     **error,
+                                gint         saved_errno,
+                                const char  *format,
+                                ...)
+{
+  gs_free char *formatted = NULL;
+  va_list args;
+  
+  va_start (args, format);
+  formatted = g_strdup_vprintf (format, args);
+  va_end (args);
+  
+  g_set_error (error,
+               G_IO_ERROR,
+               g_io_error_from_errno (saved_errno),
+               "%s: %s", formatted, g_strerror (saved_errno));
+  errno = saved_errno;
+}
diff --git a/src/gsystem-errors.h b/src/gsystem-errors.h
new file mode 100644
index 0000000..15898bc
--- /dev/null
+++ b/src/gsystem-errors.h
@@ -0,0 +1,37 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
+ *
+ * Copyright (C) 2014 Colin Walters <walters verbum org>.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef __GSYSTEM_ERRORS_H__
+#define __GSYSTEM_ERRORS_H__
+
+#include <gio/gio.h>
+#include <sys/stat.h>
+
+G_BEGIN_DECLS
+
+void gs_set_error_from_errno (GError **error, gint saved_errno);
+void gs_set_prefix_error_from_errno (GError     **error,
+                                     gint         errsv,
+                                     const char  *format,
+                                     ...) G_GNUC_PRINTF (3,4);
+
+G_END_DECLS
+
+#endif
diff --git a/src/libgsystem.h b/src/libgsystem.h
index 60884b6..9fc0c5c 100644
--- a/src/libgsystem.h
+++ b/src/libgsystem.h
@@ -40,6 +40,7 @@ G_BEGIN_DECLS
 #include <gsystem-subprocess.h>
 #endif
 #include <gsystem-log.h>
+#include <gsystem-errors.h>
 #ifndef _GSYSTEM_NO_LOCAL_ALLOC
 #include <gsystem-local-alloc.h>
 #endif