[gnome-logs/wip/field-length: 3/4] Add GlJournalError enum

[David King <davidk src gnome org>]

commit 3160ddf01d74a153246acd5f5b94a134095d5118
Author: David King <davidk gnome org>
Date:   Wed Oct 23 18:53:26 2013 +0100

    Add GlJournalError enum

 src/gl-journal.c |   25 +++++++++++++++++++++++--
 src/gl-journal.h |   19 +++++++++++++++++++
 2 files changed, 42 insertions(+), 2 deletions(-)
---
diff --git a/src/gl-journal.c b/src/gl-journal.c
index 998440e..114fdfc 100644
--- a/src/gl-journal.c
+++ b/src/gl-journal.c
@@ -31,6 +31,12 @@ typedef struct
 
 G_DEFINE_TYPE_WITH_PRIVATE (GlJournal, gl_journal, G_TYPE_OBJECT)
 
+GQuark
+gl_journal_error_quark (void)
+{
+    return g_quark_from_static_string ("gl-journal-error-quark");
+}
+
 static gboolean
 on_journal_changed (gint fd,
                     GIOCondition condition,
@@ -153,10 +159,25 @@ gl_journal_get_data (GlJournal *self,
 
     if (ret < 0)
     {
-        /* TODO: Use custom GError enumeration. */
-        g_set_error (error, G_IO_ERROR, g_io_error_from_errno (-ret),
+        gint code;
+
+        switch (-ret)
+        {
+            case ENOENT:
+                code = GL_JOURNAL_ERROR_NO_FIELD;
+                break;
+            case EADDRNOTAVAIL:
+                code = GL_JOURNAL_ERROR_INVALID_POINTER;
+                break;
+            default:
+                code = GL_JOURNAL_ERROR_FAILED;
+                break;
+        }
+
+        g_set_error (error, GL_JOURNAL_ERROR, code,
                      "Unable to get field ‘%s’ from systemd journal: %s",
                      field, g_strerror (-ret));
+
         return NULL;
     }
 
diff --git a/src/gl-journal.h b/src/gl-journal.h
index 86febf5..e5e0b06 100644
--- a/src/gl-journal.h
+++ b/src/gl-journal.h
@@ -24,6 +24,25 @@
 
 G_BEGIN_DECLS
 
+/*
+ * GlJournalError:
+ * @GL_JOURNAL_ERROR_NO_FIELD: the requested field was not found in the current
+ * journal entry
+ * @GL_JOURNAL_ERROR_INVALID_POINTER: the pointer to the current journal entry
+ * is not valid
+ * @GL_JOURNAL_ERROR_FAILED: unknown failure
+ */
+typedef enum
+{
+    GL_JOURNAL_ERROR_NO_FIELD,
+    GL_JOURNAL_ERROR_INVALID_POINTER,
+    GL_JOURNAL_ERROR_FAILED
+} GlJournalError;
+
+#define GL_JOURNAL_ERROR gl_journal_error_quark ()
+
+GQuark gl_journal_error_quark (void);
+
 typedef struct
 {
     gsize n_results;