deltas: Link to liblzma, add internal API to use it

For future static deltas work, we'll be linking to liblzma.  Since
it's fairly widespread, let's just make it a hard dependency.

src/libostree/ostree-lzma-decompressor.c

@@ -0,0 +1,137 @@
+/* -*- 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include "ostree-lzma-decompressor.h"
+#include "ostree-lzma-common.h"
+
+#include <errno.h>
+#include <lzma.h>
+#include <string.h>
+
+enum {
+  PROP_0,
+};
+
+static void _ostree_lzma_decompressor_iface_init          (GConverterIface *iface);
+
+struct _OstreeLzmaDecompressor
+{
+  GObject parent_instance;
+
+  lzma_stream lstream;
+  gboolean initialized;
+};
+
+G_DEFINE_TYPE_WITH_CODE (OstreeLzmaDecompressor, _ostree_lzma_decompressor,
+			 G_TYPE_OBJECT,
+			 G_IMPLEMENT_INTERFACE (G_TYPE_CONVERTER,
+						_ostree_lzma_decompressor_iface_init))
+
+static void
+_ostree_lzma_decompressor_finalize (GObject *object)
+{
+  OstreeLzmaDecompressor *self;
+
+  self = OSTREE_LZMA_DECOMPRESSOR (object);
+  lzma_end (&self->lstream);
+
+  G_OBJECT_CLASS (_ostree_lzma_decompressor_parent_class)->finalize (object);
+}
+
+static void
+_ostree_lzma_decompressor_init (OstreeLzmaDecompressor *self)
+{
+  lzma_stream tmp = LZMA_STREAM_INIT;
+  self->lstream = tmp;
+}
+
+static void
+_ostree_lzma_decompressor_class_init (OstreeLzmaDecompressorClass *klass)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  gobject_class->finalize = _ostree_lzma_decompressor_finalize;
+}
+
+OstreeLzmaDecompressor *
+_ostree_lzma_decompressor_new (void)
+{
+  return g_object_new (OSTREE_TYPE_LZMA_DECOMPRESSOR, NULL);
+}
+
+static void
+_ostree_lzma_decompressor_reset (GConverter *converter)
+{
+  OstreeLzmaDecompressor *self = OSTREE_LZMA_DECOMPRESSOR (converter);
+
+  if (self->initialized)
+    {
+      lzma_stream tmp = LZMA_STREAM_INIT;
+      lzma_end (&self->lstream);
+      self->lstream = tmp;
+      self->initialized = FALSE;
+    }
+}
+
+static GConverterResult
+_ostree_lzma_decompressor_convert (GConverter *converter,
+                                   const void *inbuf,
+                                   gsize       inbuf_size,
+                                   void       *outbuf,
+                                   gsize       outbuf_size,
+                                   GConverterFlags flags,
+                                   gsize      *bytes_read,
+                                   gsize      *bytes_written,
+                                   GError    **error)
+{
+  OstreeLzmaDecompressor *self = OSTREE_LZMA_DECOMPRESSOR (converter);
+  int res;
+
+  if (!self->initialized)
+    {
+      res = lzma_stream_decoder (&self->lstream, G_MAXUINT64, 0);
+      if (res != LZMA_OK)
+        goto out;
+      self->initialized = TRUE;
+    }
+
+  self->lstream.next_in = (void *)inbuf;
+  self->lstream.avail_in = inbuf_size;
+
+  self->lstream.next_out = outbuf;
+  self->lstream.avail_out = outbuf_size;
+
+  res = lzma_code (&self->lstream, LZMA_RUN);
+  if (res != LZMA_OK && res != LZMA_STREAM_END)
+    goto out;
+
+  *bytes_read = inbuf_size - self->lstream.avail_in;
+  *bytes_written = outbuf_size - self->lstream.avail_out;
+
+ out:
+  return _ostree_lzma_return (res, error);
+}
+
+static void
+_ostree_lzma_decompressor_iface_init (GConverterIface *iface)
+{
+  iface->convert = _ostree_lzma_decompressor_convert;
+  iface->reset = _ostree_lzma_decompressor_reset;
+}