core: Clean up checksumming

Don't expose GChecksum in APIs.  Add a new stream class which allows
us to pass an input stream somewhere, but gather a checksum as it's
read.

Move some bits of the internals towards binary csums.

src/libostree/ostree-checksum-input-stream.c

@@ -0,0 +1,169 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
+ * 
+ * Copyright (C) 2011 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 <gio/gio.h>
+#include "ostree-checksum-input-stream.h"
+
+enum {
+  PROP_0,
+  PROP_CHECKSUM
+};
+
+G_DEFINE_TYPE (OstreeChecksumInputStream, ostree_checksum_input_stream, G_TYPE_FILTER_INPUT_STREAM)
+
+struct _OstreeChecksumInputStreamPrivate {
+  GChecksum *checksum;
+};
+
+static void     ostree_checksum_input_stream_set_property (GObject              *object,
+                                                           guint                 prop_id,
+                                                           const GValue         *value,
+                                                           GParamSpec           *pspec);
+static void     ostree_checksum_input_stream_get_property (GObject              *object,
+                                                           guint                 prop_id,
+                                                           GValue               *value,
+                                                           GParamSpec           *pspec);
+static gssize   ostree_checksum_input_stream_read         (GInputStream         *stream,
+                                                           void                 *buffer,
+                                                           gsize                 count,
+                                                           GCancellable         *cancellable,
+                                                           GError              **error);
+
+static void
+ostree_checksum_input_stream_class_init (OstreeChecksumInputStreamClass *klass)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+  GInputStreamClass *stream_class = G_INPUT_STREAM_CLASS (klass);
+  
+  g_type_class_add_private (klass, sizeof (OstreeChecksumInputStreamPrivate));
+
+  gobject_class->get_property = ostree_checksum_input_stream_get_property;
+  gobject_class->set_property = ostree_checksum_input_stream_set_property;
+
+  stream_class->read_fn = ostree_checksum_input_stream_read;
+
+  /**
+   * OstreeChecksumInputStream:checksum:
+   *
+   * The checksum that the stream updates.
+   */
+  g_object_class_install_property (gobject_class,
+				   PROP_CHECKSUM,
+				   g_param_spec_pointer ("checksum",
+							 "", "",
+							 G_PARAM_READWRITE |
+							 G_PARAM_CONSTRUCT_ONLY |
+							 G_PARAM_STATIC_STRINGS));
+
+}
+
+static void
+ostree_checksum_input_stream_set_property (GObject         *object,
+					     guint            prop_id,
+					     const GValue    *value,
+					     GParamSpec      *pspec)
+{
+  OstreeChecksumInputStream *self;
+  
+  self = OSTREE_CHECKSUM_INPUT_STREAM (object);
+
+  switch (prop_id)
+    {
+    case PROP_CHECKSUM:
+      self->priv->checksum = g_value_get_pointer (value);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+ostree_checksum_input_stream_get_property (GObject    *object,
+					     guint       prop_id,
+					     GValue     *value,
+					     GParamSpec *pspec)
+{
+  OstreeChecksumInputStream *self;
+
+  self = OSTREE_CHECKSUM_INPUT_STREAM (object);
+
+  switch (prop_id)
+    {
+    case PROP_CHECKSUM:
+      g_value_set_pointer (value, self->priv->checksum);
+      break;
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+ostree_checksum_input_stream_init (OstreeChecksumInputStream *self)
+{
+  self->priv = G_TYPE_INSTANCE_GET_PRIVATE (self,
+					    OSTREE_TYPE_CHECKSUM_INPUT_STREAM,
+					    OstreeChecksumInputStreamPrivate);
+
+}
+
+OstreeChecksumInputStream *
+ostree_checksum_input_stream_new (GInputStream    *base,
+                                  GChecksum       *checksum)
+{
+  OstreeChecksumInputStream *stream;
+
+  g_return_val_if_fail (G_IS_INPUT_STREAM (base), NULL);
+
+  stream = g_object_new (OSTREE_TYPE_CHECKSUM_INPUT_STREAM,
+			 "base-stream", base,
+                         "checksum", checksum,
+			 NULL);
+
+  return (OstreeChecksumInputStream*) (stream);
+}
+
+static gssize
+ostree_checksum_input_stream_read (GInputStream  *stream,
+                                   void          *buffer,
+                                   gsize          count,
+                                   GCancellable  *cancellable,
+                                   GError       **error)
+{
+  OstreeChecksumInputStream *self = (OstreeChecksumInputStream*) stream;
+  GFilterInputStream *fself = (GFilterInputStream*) self;
+  gssize res = -1;
+
+  if (g_cancellable_set_error_if_cancelled (cancellable, error))
+    return -1;
+
+  res = g_input_stream_read (fself->base_stream,
+                             buffer,
+                             count,
+                             cancellable,
+                             error);
+  if (res > 0)
+    g_checksum_update (self->priv->checksum, buffer, res);
+
+  return res;
+}