[gnome-software] Rewrite the os-release parser and factor it out to a separate file

[Kalev Lember <klember src gnome org>]

commit e455069e8ec35ad64aa32660b52a05e06cf31074
Author: Kalev Lember <klember redhat com>
Date:   Tue Jan 19 18:52:09 2016 +0100

    Rewrite the os-release parser and factor it out to a separate file
    
    This code is licensed under LGPLv2+ to make it easier to reuse it in
    other projects in the future.

 src/Makefile.am     |    2 +
 src/gs-os-release.c |  129 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/gs-os-release.h |   47 ++++++++++++++++++
 3 files changed, 178 insertions(+), 0 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index 35e3553..0a66e64 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -133,6 +133,8 @@ gnome_software_SOURCES =                            \
        gs-hiding-box.c                                 \
        gs-language.c                                   \
        gs-language.h                                   \
+       gs-os-release.c                                 \
+       gs-os-release.h                                 \
        gs-page.c                                       \
        gs-page.h                                       \
        gs-plugin.c                                     \
diff --git a/src/gs-os-release.c b/src/gs-os-release.c
new file mode 100644
index 0000000..9c639af
--- /dev/null
+++ b/src/gs-os-release.c
@@ -0,0 +1,129 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
+ *
+ * Copyright (C) 2016 Kalev Lember <klember redhat com>
+ *
+ * Licensed under the GNU Lesser General Public License Version 2.1
+ *
+ * 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 2.1 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#include "config.h"
+
+#include "gs-os-release.h"
+
+#include <string.h>
+
+G_DEFINE_QUARK (gs-os-release-error-quark, gs_os_release_error)
+
+/* strip any quotes surrounding the string */
+static gchar *
+dequote (gchar *s)
+{
+       size_t len;
+
+       g_assert (s != NULL);
+
+       len = strlen (s);
+       if (len >= 2 &&
+           *s == *(s + len - 1) &&
+           (*s == '"' || *s == '\'')) {
+               s[len - 1] = '\0';
+               s++;
+       }
+
+       return s;
+}
+
+static gchar *
+get_item (gchar *line, const gchar *key)
+{
+       g_autofree gchar *label = NULL;
+
+       label = g_strconcat (key, "=", NULL);
+       if (g_str_has_prefix (line, label)) {
+               return g_strcompress (dequote (line + strlen (label)));
+       }
+
+       return NULL;
+}
+
+static gchar *
+gs_os_release_parse_variable (const gchar *variable, GError **error)
+{
+       const gchar *filename;
+       g_autofree gchar *buffer = NULL;
+
+       g_return_val_if_fail (error == NULL || *error == NULL, NULL);
+       g_return_val_if_fail (variable != NULL, NULL);
+
+       filename = "/etc/os-release";
+       if (!g_file_test (filename, G_FILE_TEST_EXISTS))
+               filename = "/usr/lib/os-release";
+
+       if (!g_file_get_contents (filename, &buffer, NULL, error))
+               return NULL;
+
+       if (buffer != NULL) {
+               gint i;
+               g_auto(GStrv) lines = NULL;
+
+               lines = g_strsplit (buffer, "\n", -1);
+               for (i = 0; lines[i] != NULL; i++) {
+                       gchar *line = g_strstrip (lines[i]);
+                       gchar *ret;
+
+                       if ((ret = get_item (line, variable)) != NULL)
+                               return ret;
+               }
+       }
+
+       g_set_error (error,
+                    GS_OS_RELEASE_ERROR,
+                    GS_OS_RELEASE_ERROR_FAILED,
+                    "could not find variable '%s' in %s", variable, filename);
+       return NULL;
+}
+
+gchar *
+gs_os_release_get_name (GError **error)
+{
+       return gs_os_release_parse_variable ("NAME", error);
+}
+
+gchar *
+gs_os_release_get_version (GError **error)
+{
+       return gs_os_release_parse_variable ("VERSION", error);
+}
+
+gchar *
+gs_os_release_get_id (GError **error)
+{
+       return gs_os_release_parse_variable ("ID", error);
+}
+
+gchar *
+gs_os_release_get_version_id (GError **error)
+{
+       return gs_os_release_parse_variable ("VERSION_ID", error);
+}
+
+gchar *
+gs_os_release_get_pretty_name (GError **error)
+{
+       return gs_os_release_parse_variable ("PRETTY_NAME", error);
+}
+
+/* vim: set noexpandtab: */
diff --git a/src/gs-os-release.h b/src/gs-os-release.h
new file mode 100644
index 0000000..cc9b7c7
--- /dev/null
+++ b/src/gs-os-release.h
@@ -0,0 +1,47 @@
+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*-
+ *
+ * Copyright (C) 2016 Kalev Lember <klember redhat com>
+ *
+ * Licensed under the GNU Lesser General Public License Version 2.1
+ *
+ * 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 2.1 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#ifndef __GS_OS_RELEASE_H
+#define __GS_OS_RELEASE_H
+
+#include <glib.h>
+
+G_BEGIN_DECLS
+
+#define GS_OS_RELEASE_ERROR gs_os_release_error_quark ()
+
+typedef enum
+{
+       GS_OS_RELEASE_ERROR_FAILED
+} GsOsReleaseError;
+
+GQuark           gs_os_release_error_quark                     (void);
+gchar           *gs_os_release_get_name                (GError         **error);
+gchar           *gs_os_release_get_version             (GError         **error);
+gchar           *gs_os_release_get_id                  (GError         **error);
+gchar           *gs_os_release_get_version_id          (GError         **error);
+gchar           *gs_os_release_get_pretty_name         (GError         **error);
+
+G_END_DECLS
+
+#endif /* __GS_OS_RELEASE_H */
+
+/* vim: set noexpandtab: */