[gnome-photos/wip/rishi/buffer-decoder: 5/16] Add PhotosGeglBufferLoader

[Debarshi Ray <debarshir src gnome org>]

commit b376206eb5c687f0419fb0ba21f78fd17f1a5593
Author: Debarshi Ray <debarshir gnome org>
Date:   Sun Apr 29 00:20:29 2018 +0200

    Add PhotosGeglBufferLoader
    
    https://gitlab.gnome.org/GNOME/gnome-photos/issues/63

 src/Makefile.am                 |   4 +
 src/meson.build                 |   1 +
 src/photos-gegl-buffer-loader.c | 596 ++++++++++++++++++++++++++++++++++++++++
 src/photos-gegl-buffer-loader.h |  59 ++++
 4 files changed, 660 insertions(+)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index 3798d4b4..79cfcaa2 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -106,6 +106,8 @@ gnome_photos_SOURCES = \
        photos-gegl.h \
        photos-gegl-buffer-codec.c \
        photos-gegl-buffer-codec.h \
+       photos-gegl-buffer-loader.c \
+       photos-gegl-buffer-loader.h \
        photos-gesture-zoom.c \
        photos-gesture-zoom.h \
        photos-glib.c \
@@ -326,6 +328,8 @@ gnome_photos_thumbnailer_SOURCES = \
        photos-gegl.h \
        photos-gegl-buffer-codec.c \
        photos-gegl-buffer-codec.h \
+       photos-gegl-buffer-loader.c \
+       photos-gegl-buffer-loader.h \
        photos-glib.c \
        photos-glib.h \
        photos-jpeg-count.c \
diff --git a/src/meson.build b/src/meson.build
index 0313bcf4..56c53d4f 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -3,6 +3,7 @@ common_sources = files(
   'photos-error.c',
   'photos-gegl.c',
   'photos-gegl-buffer-codec.c',
+  'photos-gegl-buffer-loader.c',
   'photos-glib.c',
   'photos-jpeg-count.c',
   'photos-operation-insta-curve.c',
diff --git a/src/photos-gegl-buffer-loader.c b/src/photos-gegl-buffer-loader.c
new file mode 100644
index 00000000..0e88e2ea
--- /dev/null
+++ b/src/photos-gegl-buffer-loader.c
@@ -0,0 +1,596 @@
+/*
+ * Photos - access, organize and share your photos on GNOME
+ * Copyright © 1999 The Free Software Foundation
+ * Copyright © 2018 Red Hat, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Based on code from:
+ *   + GdkPixbuf
+ */
+
+
+#include "config.h"
+
+#include <string.h>
+
+#include <glib/gi18n.h>
+
+#include "photos-error.h"
+#include "photos-gegl-buffer-codec.h"
+#include "photos-gegl-buffer-loader.h"
+#include "photos-marshalers.h"
+
+
+enum
+{
+  SNIFF_BUFFER_SIZE = 4096
+};
+
+struct _PhotosGeglBufferLoader
+{
+  GObject parent_instance;
+  GFile *file;
+  PhotosGeglBufferCodec *codec;
+  gboolean closed;
+  gboolean preserve_aspect_ratio;
+  gint height;
+  gint width;
+  guchar header_buf[SNIFF_BUFFER_SIZE];
+  gsize header_buf_offset;
+};
+
+enum
+{
+  PROP_0,
+  PROP_BUFFER,
+  PROP_FILE,
+  PROP_HEIGHT,
+  PROP_PRESERVE_ASPECT_RATIO,
+  PROP_WIDTH
+};
+
+enum
+{
+  SIZE_PREPARED,
+  LAST_SIGNAL
+};
+
+static guint signals[LAST_SIGNAL] = { 0 };
+
+
+G_DEFINE_TYPE (PhotosGeglBufferLoader, photos_gegl_buffer_loader, G_TYPE_OBJECT);
+
+
+static PhotosGeglBufferCodec *
+photos_gegl_buffer_loader_find_codec (PhotosGeglBufferLoader *self, GError **error)
+{
+  GIOExtensionPoint *extension_point;
+  GList *extensions;
+  GList *l;
+  PhotosGeglBufferCodec *ret_val = NULL;
+  g_autoptr (PhotosGeglBufferCodec) codec = NULL;
+  gboolean uncertain;
+  g_autofree gchar *content_type = NULL;
+  g_autofree gchar *path = NULL;
+
+  if (self->file != NULL)
+    path = g_file_get_path (self->file);
+
+  content_type = g_content_type_guess (NULL, self->header_buf, self->header_buf_offset, &uncertain);
+  if ((uncertain
+       || g_strcmp0 (content_type, "text/plain") == 0
+       || g_strcmp0 (content_type, "application/gzip") == 0)
+      && path != NULL)
+    {
+      g_free (content_type);
+      content_type = g_content_type_guess (path, self->header_buf, self->header_buf_offset, NULL);
+    }
+
+  extension_point = g_io_extension_point_lookup (PHOTOS_GEGL_BUFFER_CODEC_EXTENSION_POINT_NAME);
+  extensions = g_io_extension_point_get_extensions (extension_point);
+  for (l = extensions; l != NULL; l = l->next)
+    {
+      GIOExtension *extension = (GIOExtension *) l->data;
+      PhotosGeglBufferCodecClass *buffer_codec_class; /* TODO: use g_autoptr */
+      gint i;
+
+      buffer_codec_class = PHOTOS_GEGL_BUFFER_CODEC_CLASS (g_io_extension_ref_class (extension));
+      for (i = 0; buffer_codec_class->mime_types[i] != NULL; i++)
+        {
+          g_autofree gchar *codec_content_type = NULL;
+
+          codec_content_type = g_content_type_from_mime_type (buffer_codec_class->mime_types[i]);
+          if (g_content_type_equals (codec_content_type, content_type))
+            {
+              GType type;
+
+              type = g_io_extension_get_type (extension);
+              codec = PHOTOS_GEGL_BUFFER_CODEC (g_object_new (type, NULL));
+              break;
+            }
+        }
+
+      g_type_class_unref (buffer_codec_class);
+    }
+
+  if (codec == NULL)
+    {
+      if (path == NULL)
+        {
+          g_set_error_literal (error, PHOTOS_ERROR, 0, _("Unrecognized image file format"));
+        }
+      else
+        {
+          g_autofree gchar *display_name = NULL;
+
+          display_name = g_filename_display_name (path);
+          g_set_error (error,
+                       PHOTOS_ERROR,
+                       0,
+                       _("Couldn’t recognize the image file format for file “%s”"),
+                       display_name);
+        }
+
+      goto out;
+    }
+
+  ret_val = g_object_ref (codec);
+
+ out:
+  return ret_val;
+}
+
+
+static void
+photos_gegl_buffer_loader_notify_buffer (PhotosGeglBufferLoader *self)
+{
+  g_object_notify (G_OBJECT (self), "buffer");
+}
+
+
+static void
+photos_gegl_buffer_loader_size_prepared (PhotosGeglBufferLoader *self, guint width, guint height)
+{
+  g_signal_emit (self, signals[SIZE_PREPARED], 0, width, height);
+
+  if (self->preserve_aspect_ratio && (self->height > 0 || self->width > 0))
+    {
+      if (self->width < 0)
+        {
+          width = (guint) ((gdouble) width * (gdouble) self->height / (gdouble) height);
+          height = (guint) self->height;
+        }
+      else if (self->height < 0)
+        {
+          height = (guint) ((gdouble) height * (gdouble) self->width / (gdouble) width);
+          width = (guint) self->width;
+        }
+      else if ((gdouble) height / (gdouble) width > (gdouble) self->height / (gdouble) self->width)
+        {
+          width = (guint) ((gdouble) width * (gdouble) self->height / (gdouble) height + 0.5);
+          height = (guint) self->height;
+        }
+      else
+        {
+          height = (guint) ((gdouble) height * (gdouble) self->width / (gdouble) width + 0.5);
+          width = (guint) self->width;
+        }
+    }
+  else
+    {
+      if (self->height > 0)
+        height = (guint) self->height;
+
+      if (self->width > 0)
+        width = (guint) self->width;
+    }
+
+  height = MAX (height, 1);
+  width = MAX (width, 1);
+
+  photos_gegl_buffer_codec_set_height (self->codec, height);
+  photos_gegl_buffer_codec_set_width (self->codec, width);
+}
+
+
+static gboolean
+photos_gegl_buffer_loader_load_codec (PhotosGeglBufferLoader *self, const gchar *codec_name, GError **error)
+{
+  gboolean ret_val = FALSE;
+
+  g_return_val_if_fail (self->codec == NULL, FALSE);
+
+  if (codec_name == NULL)
+    {
+      self->codec = photos_gegl_buffer_loader_find_codec (self, error);
+      if (self->codec == NULL)
+        goto out;
+    }
+  else
+    {
+      GIOExtension *extension;
+      GIOExtensionPoint *extension_point;
+      GType type;
+
+      extension_point = g_io_extension_point_lookup (PHOTOS_GEGL_BUFFER_CODEC_EXTENSION_POINT_NAME);
+      extension = g_io_extension_point_get_extension_by_name (extension_point, codec_name);
+      if (extension == NULL)
+        {
+          g_set_error (error, PHOTOS_ERROR, 0, _("Codec type “%s” is not supported"), codec_name);
+          goto out;
+        }
+
+      type = g_io_extension_get_type (extension);
+      self->codec = PHOTOS_GEGL_BUFFER_CODEC (g_object_new (type, NULL));
+    }
+
+  g_signal_connect_swapped (self->codec,
+                            "notify::buffer",
+                            G_CALLBACK (photos_gegl_buffer_loader_notify_buffer),
+                            self);
+
+  g_signal_connect_swapped (self->codec,
+                            "size-prepared",
+                            G_CALLBACK (photos_gegl_buffer_loader_size_prepared),
+                            self);
+
+  if (!photos_gegl_buffer_codec_load_begin (self->codec, error))
+    goto out;
+
+  if (self->header_buf_offset > 0)
+    {
+      if (!photos_gegl_buffer_codec_load_increment (self->codec, self->header_buf, self->header_buf_offset, 
error))
+        goto out;
+    }
+
+  ret_val = TRUE;
+
+ out:
+  return ret_val;
+}
+
+
+static gsize
+photos_gegl_buffer_loader_eat_header (PhotosGeglBufferLoader *self, const guchar *buf, gsize count, GError 
**error)
+{
+  gsize n_bytes_to_eat;
+  gsize ret_val = 0;
+
+  g_return_val_if_fail ((gssize) self->header_buf_offset < SNIFF_BUFFER_SIZE, 0);
+
+  n_bytes_to_eat = MIN (SNIFF_BUFFER_SIZE - self->header_buf_offset, count);
+  memcpy (self->header_buf + self->header_buf_offset, buf, n_bytes_to_eat);
+
+  self->header_buf_offset += n_bytes_to_eat;
+  g_return_val_if_fail (self->header_buf_offset <= SNIFF_BUFFER_SIZE, 0);
+
+  if (self->header_buf_offset == SNIFF_BUFFER_SIZE)
+    {
+      if (!photos_gegl_buffer_loader_load_codec (self, NULL, error))
+        goto out;
+    }
+  else
+    {
+      g_return_val_if_fail (n_bytes_to_eat == count, 0);
+    }
+
+  ret_val = n_bytes_to_eat;
+
+ out:
+  return ret_val;
+}
+
+
+static void
+photos_gegl_buffer_loader_dispose (GObject *object)
+{
+  PhotosGeglBufferLoader *self = PHOTOS_GEGL_BUFFER_LOADER (object);
+
+  g_clear_object (&self->file);
+  g_clear_object (&self->codec);
+
+  G_OBJECT_CLASS (photos_gegl_buffer_loader_parent_class)->dispose (object);
+}
+
+
+static void
+photos_gegl_buffer_loader_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
+{
+  PhotosGeglBufferLoader *self = PHOTOS_GEGL_BUFFER_LOADER (object);
+
+  switch (prop_id)
+    {
+    case PROP_BUFFER:
+      {
+        GeglBuffer *buffer;
+
+        buffer = photos_gegl_buffer_loader_get_buffer (self);
+        g_value_set_object (value, buffer);
+        break;
+      }
+
+    case PROP_FILE:
+      g_value_set_object (value, self->file);
+      break;
+
+    case PROP_HEIGHT:
+      g_value_set_int (value, self->height);
+      break;
+
+    case PROP_PRESERVE_ASPECT_RATIO:
+      g_value_set_boolean (value, self->preserve_aspect_ratio);
+      break;
+
+    case PROP_WIDTH:
+      g_value_set_int (value, self->width);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+
+static void
+photos_gegl_buffer_loader_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec 
*pspec)
+{
+  PhotosGeglBufferLoader *self = PHOTOS_GEGL_BUFFER_LOADER (object);
+
+  switch (prop_id)
+    {
+    case PROP_FILE:
+      self->file = G_FILE (g_value_dup_object (value));
+      break;
+
+    case PROP_HEIGHT:
+      self->height = g_value_get_int (value);
+      break;
+
+    case PROP_PRESERVE_ASPECT_RATIO:
+      self->preserve_aspect_ratio = g_value_get_boolean (value);
+      break;
+
+    case PROP_WIDTH:
+      self->width = g_value_get_int (value);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+
+static void
+photos_gegl_buffer_loader_init (PhotosGeglBufferLoader *self)
+{
+}
+
+
+static void
+photos_gegl_buffer_loader_class_init (PhotosGeglBufferLoaderClass *class)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (class);
+
+  object_class->dispose = photos_gegl_buffer_loader_dispose;
+  object_class->get_property = photos_gegl_buffer_loader_get_property;
+  object_class->set_property = photos_gegl_buffer_loader_set_property;
+
+  g_object_class_install_property (object_class,
+                                   PROP_BUFFER,
+                                   g_param_spec_object ("buffer",
+                                                        "Buffer",
+                                                        "The GeglBuffer being loaded",
+                                                        GEGL_TYPE_BUFFER,
+                                                        G_PARAM_READABLE
+                                                        | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (object_class,
+                                   PROP_FILE,
+                                   g_param_spec_object ("file",
+                                                        "File",
+                                                        "The file from which to load a GeglBuffer",
+                                                        G_TYPE_FILE,
+                                                        G_PARAM_CONSTRUCT_ONLY
+                                                        | G_PARAM_READWRITE
+                                                        | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (object_class,
+                                   PROP_HEIGHT,
+                                   g_param_spec_int ("height",
+                                                     "Height",
+                                                     "The desired height of the GeglBuffer being loaded",
+                                                     -1,
+                                                     G_MAXINT,
+                                                     -1,
+                                                     G_PARAM_CONSTRUCT_ONLY
+                                                     | G_PARAM_READWRITE
+                                                     | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (object_class,
+                                   PROP_PRESERVE_ASPECT_RATIO,
+                                   g_param_spec_boolean ("preserve-aspect-ratio",
+                                                         "Preserve aspect ratio",
+                                                         "Whether to preserve the aspect ratio of the 
GeglBuffer "
+                                                         "when scaling, or not",
+                                                         TRUE,
+                                                         G_PARAM_CONSTRUCT_ONLY
+                                                         | G_PARAM_READWRITE
+                                                         | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_property (object_class,
+                                   PROP_WIDTH,
+                                   g_param_spec_int ("width",
+                                                     "Width",
+                                                     "The desired width of the GeglBuffer being loaded",
+                                                     -1,
+                                                     G_MAXINT,
+                                                     -1,
+                                                     G_PARAM_CONSTRUCT_ONLY
+                                                     | G_PARAM_READWRITE
+                                                     | G_PARAM_STATIC_STRINGS));
+
+  signals[SIZE_PREPARED] = g_signal_new ("size-prepared",
+                                         G_TYPE_FROM_CLASS (class),
+                                         G_SIGNAL_RUN_LAST,
+                                         0,
+                                         NULL, /* accumulator */
+                                         NULL, /* accu_data */
+                                         _photos_marshal_VOID__UINT_UINT,
+                                         G_TYPE_NONE,
+                                         2,
+                                         G_TYPE_UINT,
+                                         G_TYPE_UINT);
+}
+
+
+GeglBuffer *
+photos_gegl_buffer_loader_get_buffer (PhotosGeglBufferLoader *self)
+{
+  GeglBuffer *ret_val = NULL;
+
+  g_return_val_if_fail (PHOTOS_IS_GEGL_BUFFER_LOADER (self), NULL);
+
+  if (self->codec == NULL)
+    goto out;
+
+  ret_val = photos_gegl_buffer_codec_get_buffer (self->codec);
+
+ out:
+  return ret_val;
+}
+
+
+GFile *
+photos_gegl_buffer_loader_get_file (PhotosGeglBufferLoader *self)
+{
+  g_return_val_if_fail (PHOTOS_IS_GEGL_BUFFER_LOADER (self), NULL);
+  return self->file;
+}
+
+
+gint
+photos_gegl_buffer_loader_get_height (PhotosGeglBufferLoader *self)
+{
+  g_return_val_if_fail (PHOTOS_IS_GEGL_BUFFER_LOADER (self), -1);
+  return self->height;
+}
+
+
+gboolean
+photos_gegl_buffer_loader_get_preserve_aspect_ratio (PhotosGeglBufferLoader *self)
+{
+  g_return_val_if_fail (PHOTOS_IS_GEGL_BUFFER_LOADER (self), FALSE);
+  return self->preserve_aspect_ratio;
+}
+
+
+gint
+photos_gegl_buffer_loader_get_width (PhotosGeglBufferLoader *self)
+{
+  g_return_val_if_fail (PHOTOS_IS_GEGL_BUFFER_LOADER (self), -1);
+  return self->width;
+}
+
+
+gboolean
+photos_gegl_buffer_loader_close (PhotosGeglBufferLoader *self, GError **error)
+{
+  g_return_val_if_fail (PHOTOS_IS_GEGL_BUFFER_LOADER (self), FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  if (self->closed)
+    goto out;
+
+  if (self->codec == NULL)
+    {
+      {
+        g_autoptr (GError) local_error = NULL;
+
+        if (!photos_gegl_buffer_loader_load_codec (self, NULL, &local_error))
+          {
+            g_propagate_error (error, g_steal_pointer (&local_error));
+            goto out;
+          }
+      }
+    }
+
+  g_return_val_if_fail (PHOTOS_IS_GEGL_BUFFER_CODEC (self->codec), FALSE);
+
+  {
+    g_autoptr (GError) local_error = NULL;
+
+    if (!photos_gegl_buffer_codec_load_stop (self->codec, &local_error))
+      {
+        g_propagate_error (error, g_steal_pointer (&local_error));
+        goto out;
+      }
+  }
+
+  self->closed = TRUE;
+
+ out:
+  return self->closed;
+}
+
+
+gboolean
+photos_gegl_buffer_loader_write_bytes (PhotosGeglBufferLoader *self,
+                                       GBytes *bytes,
+                                       GCancellable *cancellable,
+                                       GError **error)
+{
+  gboolean ret_val = FALSE;
+  gsize count;
+  const guchar *data;
+
+  g_return_val_if_fail (PHOTOS_IS_GEGL_BUFFER_LOADER (self), FALSE);
+  g_return_val_if_fail (bytes != NULL, FALSE);
+  g_return_val_if_fail (cancellable == NULL || G_IS_CANCELLABLE (cancellable), FALSE);
+  g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
+
+  data = (const guchar *) g_bytes_get_data (bytes, &count);
+  g_return_val_if_fail (data != NULL, FALSE);
+  g_return_val_if_fail (count > 0, FALSE);
+
+  g_return_val_if_fail (!self->closed, FALSE);
+
+  if (self->codec == NULL)
+    {
+      gssize eaten;
+
+      eaten = photos_gegl_buffer_loader_eat_header (self, data, count, error);
+      if (eaten == 0)
+        goto out;
+
+      count -= eaten;
+      data += eaten;
+    }
+
+  g_return_val_if_fail (count == 0 || self->codec != NULL, FALSE);
+
+  if (count > 0)
+    {
+      if (!photos_gegl_buffer_codec_load_increment (self->codec, data, count, error))
+        goto out;
+    }
+
+  ret_val = TRUE;
+
+ out:
+  return ret_val;
+}
diff --git a/src/photos-gegl-buffer-loader.h b/src/photos-gegl-buffer-loader.h
new file mode 100644
index 00000000..26f55b47
--- /dev/null
+++ b/src/photos-gegl-buffer-loader.h
@@ -0,0 +1,59 @@
+/*
+ * Photos - access, organize and share your photos on GNOME
+ * Copyright © 1999 The Free Software Foundation
+ * Copyright © 2018 Red Hat, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Based on code from:
+ *   + GdkPixbuf
+ */
+
+#ifndef PHOTOS_GEGL_BUFFER_LOADER_H
+#define PHOTOS_GEGL_BUFFER_LOADER_H
+
+#include <gegl.h>
+#include <gio/gio.h>
+
+G_BEGIN_DECLS
+
+#define PHOTOS_TYPE_GEGL_BUFFER_LOADER (photos_gegl_buffer_loader_get_type ())
+G_DECLARE_FINAL_TYPE (PhotosGeglBufferLoader,
+                      photos_gegl_buffer_loader,
+                      PHOTOS,
+                      GEGL_BUFFER_LOADER,
+                      GObject);
+
+GeglBuffer              *photos_gegl_buffer_loader_get_buffer                 (PhotosGeglBufferLoader *self);
+
+GFile                   *photos_gegl_buffer_loader_get_file                   (PhotosGeglBufferLoader *self);
+
+gint                     photos_gegl_buffer_loader_get_height                 (PhotosGeglBufferLoader *self);
+
+gboolean                 photos_gegl_buffer_loader_get_preserve_aspect_ratio  (PhotosGeglBufferLoader *self);
+
+gint                     photos_gegl_buffer_loader_get_width                  (PhotosGeglBufferLoader *self);
+
+gboolean                 photos_gegl_buffer_loader_close                      (PhotosGeglBufferLoader *self,
+                                                                               GError **error);
+
+gboolean                 photos_gegl_buffer_loader_write_bytes                (PhotosGeglBufferLoader *self,
+                                                                               GBytes *bytes,
+                                                                               GCancellable *cancellable,
+                                                                               GError **error);
+
+G_END_DECLS
+
+#endif /* PHOTOS_GEGL_BUFFER_LOADER_H */