[gegl] png-load: Move function for opening stream to library

[Jon Nordby <jonnor src gnome org>]

commit 14b0373b2e86e42011e4488030d307912fec61d0
Author: Jon Nordby <jononor gmail com>
Date:   Mon Nov 10 01:12:32 2014 +0100

    png-load: Move function for opening stream to library
    
    In order to be able to reuse it in the other file loaders,
    like gegl:jpg-load.
    In private header for now.

 gegl/Makefile.am               |    2 +
 gegl/gegl-gio-private.h        |   32 +++++++++++++++++
 gegl/gegl-gio.c                |   76 ++++++++++++++++++++++++++++++++++++++++
 operations/external/png-load.c |   57 ++----------------------------
 4 files changed, 113 insertions(+), 54 deletions(-)
---
diff --git a/gegl/Makefile.am b/gegl/Makefile.am
index 67c4529..9e3e304 100644
--- a/gegl/Makefile.am
+++ b/gegl/Makefile.am
@@ -94,6 +94,7 @@ GEGL_sources = \
        gegl-utils.c                    \
        gegl-lookup.c                   \
        gegl-xml.c                      \
+       gegl-gio.c                      \
        gegl-random.c                   \
        gegl-matrix.c                   \
        \
@@ -114,6 +115,7 @@ GEGL_sources = \
        gegl-op.h                           \
        gegl-plugin.h                   \
        gegl-random-private.h           \
+       gegl-gio-private.h              \
        gegl-types-internal.h           \
        gegl-xml.h
 
diff --git a/gegl/gegl-gio-private.h b/gegl/gegl-gio-private.h
new file mode 100644
index 0000000..d918e4d
--- /dev/null
+++ b/gegl/gegl-gio-private.h
@@ -0,0 +1,32 @@
+/* This file is part of GEGL
+ *
+ * GEGL 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 3 of the License, or (at your option) any later version.
+ *
+ * GEGL 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 GEGL; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2014 Jon Nordby, The Grid <jononor gmail com>
+ */
+
+#include <glib.h>
+#include <gio/gio.h>
+
+G_BEGIN_DECLS
+
+#ifndef __GEGL_GIO_PRIVATE_H__
+#define __GEGL_GIO_PRIVATE_H__
+
+GInputStream *
+gegl_gio_open_input_stream(const gchar *uri, const gchar *path, GFile **out_file, GError **err);
+
+#endif // __GEGL_GIO_PRIVATE_H__
+
+G_END_DECLS
diff --git a/gegl/gegl-gio.c b/gegl/gegl-gio.c
new file mode 100644
index 0000000..b572d7e
--- /dev/null
+++ b/gegl/gegl-gio.c
@@ -0,0 +1,76 @@
+/* This file is part of GEGL
+ *
+ * GEGL 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 3 of the License, or (at your option) any later version.
+ *
+ * GEGL 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 GEGL; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright 2014 Jon Nordby, The Grid <jononor gmail com>
+ */
+
+#include <gegl-gio-private.h>
+#include <string.h>
+
+#ifdef G_OS_WIN32
+#include <gio/gwin32inputstream.h>  
+#else
+#include <gio/gunixinputstream.h>
+#endif
+
+/**
+ * gegl_gio_open_input_stream:
+ * @uri: (allow none) URI to open. @uri is preferred over @path if both are set
+ * @path: (allow none) path to open. 
+ * @out_file: (out) (transfer full): return location for GFile, if stream is for a file
+ *
+ * Return value: (transfer full): A new #GInputStream, free with g_object_unref()
+ *
+ * Note: currently private API
+ */
+GInputStream *
+gegl_gio_open_input_stream(const gchar *uri, const gchar *path, GFile **out_file, GError **err)
+{
+  GFile *infile = NULL;
+  GInputStream *fis = NULL;
+  g_return_val_if_fail(uri || path, NULL);
+  g_return_val_if_fail(out_file, NULL);
+
+  if (path && g_strcmp0(path, "-") == 0)
+    {
+      const gboolean close_fd = FALSE;
+      infile = NULL;
+#ifdef G_OS_WIN32 // untested :)
+      fis = g_win32_input_stream_new(stdin, close_fd);
+#else
+      fis = g_unix_input_stream_new(STDIN_FILENO, close_fd);
+#endif
+    }
+  else if (uri && strlen(uri) > 0)
+    {
+      infile = g_file_new_for_uri(uri);
+    }
+  else if (path && strlen(path) > 0)
+    {
+      infile = g_file_new_for_path(path);
+    }
+  else {
+    return NULL;
+  }
+
+  if (infile)
+    {
+      g_assert(!fis);
+      fis = G_INPUT_STREAM(g_file_read(infile, NULL, err));
+      *out_file = infile;
+    }
+
+  return fis;
+}
diff --git a/operations/external/png-load.c b/operations/external/png-load.c
index eae9aad..3f91eb4 100644
--- a/operations/external/png-load.c
+++ b/operations/external/png-load.c
@@ -20,13 +20,7 @@
 
 #include "config.h"
 #include <glib/gi18n-lib.h>
-#include <gio/gio.h>
-
-#ifdef G_OS_WIN32
-#include <gio/gwin32inputstream.h>  
-#else
-#include <gio/gunixinputstream.h>
-#endif
+#include <gegl-gio-private.h>
 
 #ifdef GEGL_PROPERTIES
 
@@ -67,7 +61,6 @@ read_fn(png_structp png_ptr, png_bytep buffer, png_size_t length)
 {
   GError *err = NULL;
   GInputStream *stream = G_INPUT_STREAM(png_get_io_ptr(png_ptr));
-  gboolean success = FALSE;
   gsize bytes_read = 0;
   g_assert(stream);
 
@@ -118,50 +111,6 @@ check_valid_png_header(GInputStream *stream, GError **err)
   return TRUE;
 }
 
-
-// TODO: move somewhere general for operations to reuse?
-static GInputStream *
-open_stream(const gchar *uri, const gchar *path, GFile **out_file, GError **err)
-{
-  GFile *infile = NULL;
-  GInputStream *fis = NULL;
-  g_return_val_if_fail(uri || path, NULL);
-  g_return_val_if_fail(out_file, NULL);
-
-  g_print("open_stream: path=%s uri=%s", path, uri);
-
-  if (path && g_strcmp0(path, "-") == 0)
-    {
-      const gboolean close_fd = FALSE;
-      infile = NULL;
-#ifdef G_OS_WIN32 // untested :)
-      fis = g_win32_input_stream_new(stdin, close_fd);
-#else
-      fis = g_unix_input_stream_new(STDIN_FILENO, close_fd);
-#endif
-    }
-  else if (uri && strlen(uri) > 0)
-    {
-      infile = g_file_new_for_uri(uri);
-    }
-  else if (path && strlen(path) > 0)
-    {
-      infile = g_file_new_for_path(path);
-    }
-  else {
-    return NULL;
-  }
-
-  if (infile)
-    {
-      g_assert(!fis);
-      fis = G_INPUT_STREAM(g_file_read(infile, NULL, err));
-      *out_file = infile;
-    }
-
-  return fis;
-}
-
 static const Babl *
 get_babl_format(int bit_depth, int color_type)
 {
@@ -470,7 +419,7 @@ get_bounding_box (GeglOperation *operation)
   GError *err = NULL;
   GFile *infile = NULL;
 
-  GInputStream *stream = open_stream(o->uri, o->path, &infile, &err);
+  GInputStream *stream = gegl_gio_open_input_stream(o->uri, o->path, &infile, &err);
   WARN_IF_ERROR(err);
   status = query_png(stream, &width, &height, &format, &err);
   WARN_IF_ERROR(err);
@@ -504,7 +453,7 @@ process (GeglOperation       *operation,
   Babl        *format = NULL;
   GError *err = NULL;
   GFile *infile = NULL;
-  GInputStream *stream = open_stream(o->uri, o->path, &infile, &err);
+  GInputStream *stream = gegl_gio_open_input_stream(o->uri, o->path, &infile, &err);
   WARN_IF_ERROR(err);
   problem = gegl_buffer_import_png (output, stream, 0, 0,
                                     &width, &height, format, &err);