[gnome-builder] diagnostic: add ide_diagnostic_hash()

[Christian Hergert <chergert src gnome org>]

commit 87c56f09b5f1e2452a0f92f35cdbe8ccbfe67862
Author: Christian Hergert <chergert redhat com>
Date:   Sat Oct 15 23:07:13 2016 -0700

    diagnostic: add ide_diagnostic_hash()
    
    This can be helpful to deduplicate diagnostics that might be similar but
    coming from multiple build targets.

 libide/diagnostics/ide-diagnostic.c |   20 ++++++++++++++++++++
 libide/diagnostics/ide-diagnostic.h |    2 ++
 2 files changed, 22 insertions(+), 0 deletions(-)
---
diff --git a/libide/diagnostics/ide-diagnostic.c b/libide/diagnostics/ide-diagnostic.c
index 015b26c..589576a 100644
--- a/libide/diagnostics/ide-diagnostic.c
+++ b/libide/diagnostics/ide-diagnostic.c
@@ -37,8 +37,28 @@ struct _IdeDiagnostic
   IdeSourceLocation     *location;
   GPtrArray             *fixits;
   GPtrArray             *ranges;
+  guint                  hash;
 };
 
+guint
+ide_diagnostic_hash (IdeDiagnostic *self)
+{
+  guint hash = self->hash;
+
+  if (hash == 0)
+    {
+      hash ^= g_str_hash (self->text ?: "");
+      if (self->location)
+        hash ^= ide_source_location_hash (self->location);
+      if (self->fixits)
+        hash ^= g_int_hash (&self->fixits->len);
+      if (self->ranges)
+        hash ^= g_int_hash (&self->ranges->len);
+    }
+
+  return hash;
+}
+
 IdeDiagnostic *
 ide_diagnostic_ref (IdeDiagnostic *self)
 {
diff --git a/libide/diagnostics/ide-diagnostic.h b/libide/diagnostics/ide-diagnostic.h
index 54503ab..a46e90e 100644
--- a/libide/diagnostics/ide-diagnostic.h
+++ b/libide/diagnostics/ide-diagnostic.h
@@ -60,6 +60,8 @@ void                   ide_diagnostic_take_range           (IdeDiagnostic
                                                             IdeSourceRange        *range);
 gint                   ide_diagnostic_compare              (const IdeDiagnostic   *a,
                                                             const IdeDiagnostic   *b);
+guint                  ide_diagnostic_hash                 (IdeDiagnostic         *self);
+
 
 const gchar           *ide_diagnostic_severity_to_string   (IdeDiagnosticSeverity severity);