[gtk+/wip/alexl/broadway4: 58/62] broadway: Add a texture cache

[Alexander Larsson <alexl src gnome org>]

commit e66a5f48766a5b04b8d2b7a3e1d16c35f7b5e7bd
Author: Alexander Larsson <alexl redhat com>
Date:   Wed Nov 29 18:16:24 2017 +0100

    broadway: Add a texture cache
    
    This ensures we never upload a texture we already have locally available.

 gdk/broadway/gdkdisplay-broadway.c |  148 +++++++++++++++++++++++++++++++++---
 gdk/broadway/gdkdisplay-broadway.h |    2 +
 2 files changed, 138 insertions(+), 12 deletions(-)
---
diff --git a/gdk/broadway/gdkdisplay-broadway.c b/gdk/broadway/gdkdisplay-broadway.c
index 59ad533..4d1b0a4 100644
--- a/gdk/broadway/gdkdisplay-broadway.c
+++ b/gdk/broadway/gdkdisplay-broadway.c
@@ -43,6 +43,92 @@
 #endif
 #include <sys/types.h>
 
+static gboolean
+compare_surface (cairo_surface_t *a,
+                 cairo_surface_t *b,
+                 int width,
+                 int height)
+{
+  unsigned char *data_a, *data_b;
+  int stride_a, stride_b;
+  int y;
+
+  data_a = cairo_image_surface_get_data (a);
+  stride_a = cairo_image_surface_get_stride (a);
+
+  data_b = cairo_image_surface_get_data (b);
+  stride_b = cairo_image_surface_get_stride (b);
+
+  for (y = 0; y < height; y++)
+    {
+      if (memcmp (data_a, data_b, 4 * width) != 0)
+        return FALSE;
+      data_a += stride_a;
+      data_b += stride_b;
+    }
+
+  return TRUE;
+}
+
+static gboolean
+gdk_texture_equal (GdkTexture *a,
+                   GdkTexture *b)
+{
+  cairo_surface_t *surface_a;
+  cairo_surface_t *surface_b;
+  gboolean res;
+
+  if (a == b)
+    return TRUE;
+
+  if (a->width != b->width ||
+      a->height != b->height)
+    return FALSE;
+
+  surface_a = gdk_texture_download_surface (a);
+  surface_b = gdk_texture_download_surface (b);
+
+  res = compare_surface (surface_a, surface_b, a->width, a->height);
+
+  cairo_surface_destroy (surface_a);
+  cairo_surface_destroy (surface_b);
+
+  return res;
+}
+
+static guint
+gdk_texture_hash (GdkTexture *self)
+{
+  cairo_surface_t *surface;
+  unsigned char *data;
+  int stride;
+  guint32 *row;
+  guint64 sum;
+  int x, y, width, height;
+  guint h;
+
+  surface = gdk_texture_download_surface (self);
+  data = cairo_image_surface_get_data (surface);
+  stride = cairo_image_surface_get_stride (surface);
+
+  width = MAX (self->width, 4);
+  height = MAX (self->height, 4);
+
+  sum = 0;
+  for (y = 0; y < height; y++, data += stride)
+    {
+      row = (guint32 *)data;
+      for (x = 0; x < width; x++)
+        sum += row[x];
+    }
+
+  cairo_surface_destroy (surface);
+
+  h = sum / (width * height);
+
+  return h ^ self->width ^ (self->height << 16);
+}
+
 static void   gdk_broadway_display_dispose            (GObject            *object);
 static void   gdk_broadway_display_finalize           (GObject            *object);
 
@@ -62,6 +148,7 @@ gdk_broadway_display_init (GdkBroadwayDisplay *display)
                                    NULL);
   gdk_monitor_set_manufacturer (display->monitor, "browser");
   gdk_monitor_set_model (display->monitor, "0");
+  display->texture_cache = g_hash_table_new ((GHashFunc)gdk_texture_hash, (GEqualFunc)gdk_texture_equal);
 }
 
 static void
@@ -380,16 +467,39 @@ gdk_broadway_display_get_last_seen_time (GdkDisplay *display)
 typedef struct {
   int id;
   GdkDisplay *display;
+  GdkTexture *in_cache;
+  GList *textures;
 } BroadwayTextureData;
 
 static void
-broadway_texture_data_free (BroadwayTextureData *data)
+broadway_texture_data_notify (BroadwayTextureData *data,
+                             GdkTexture *disposed_texture)
 {
   GdkBroadwayDisplay *broadway_display = GDK_BROADWAY_DISPLAY (data->display);
 
-  gdk_broadway_server_release_texture (broadway_display->server, data->id);
-  g_object_unref (data->display);
-  g_free (data);
+  if (data->in_cache == disposed_texture)
+    {
+      g_hash_table_remove (broadway_display->texture_cache, disposed_texture);
+      data->in_cache = NULL;
+    }
+
+  g_object_set_data (G_OBJECT (disposed_texture), "broadway-data", NULL);
+
+  data->textures = g_list_remove (data->textures, disposed_texture);
+  if (data->textures == NULL)
+    {
+      gdk_broadway_server_release_texture (broadway_display->server, data->id);
+      g_object_unref (data->display);
+      g_free (data);
+    }
+  else if (data->in_cache == NULL)
+    {
+      GdkTexture *first = data->textures->data;
+
+      data->in_cache = first;
+      g_hash_table_replace (broadway_display->texture_cache,
+                           data->in_cache, data->in_cache);
+    }
 }
 
 guint32
@@ -399,21 +509,35 @@ gdk_broadway_display_ensure_texture (GdkDisplay *display,
   GdkBroadwayDisplay *broadway_display = GDK_BROADWAY_DISPLAY (display);
   BroadwayTextureData *data;
   guint32 id;
+  GdkTexture *cached;
 
-  data = gdk_texture_get_render_data (texture, display);
+  data = g_object_get_data (G_OBJECT (texture), "broadway-data");
   if (data != NULL)
     return data->id;
 
-  id = gdk_broadway_server_upload_texture (broadway_display->server, texture);
+  cached = g_hash_table_lookup (broadway_display->texture_cache, texture);
+  if (cached)
+    data = g_object_get_data (G_OBJECT (cached), "broadway-data");
+
+  if (data == NULL)
+    {
+      id = gdk_broadway_server_upload_texture (broadway_display->server, texture);
+
+      data = g_new0 (BroadwayTextureData, 1);
+      data->id = id;
+      data->display = g_object_ref (display);
+
+      data->in_cache = texture;
+      g_hash_table_replace (broadway_display->texture_cache,
+                           data->in_cache, data->in_cache);
+    }
 
-  data = g_new0 (BroadwayTextureData, 1);
-  data->id = id;
-  data->display = g_object_ref (display);
+  data->textures = g_list_prepend (data->textures, texture);
 
-  if (!gdk_texture_set_render_data (texture, display, data, (GDestroyNotify)broadway_texture_data_free))
-    g_warning ("Failed to set render data, will leak texture");
+  g_object_weak_ref (G_OBJECT (texture), (GWeakNotify)broadway_texture_data_notify, data);
+  g_object_set_data (G_OBJECT (texture), "broadway-data", data);
 
-  return id;
+  return data->id;
 }
 
 static void
diff --git a/gdk/broadway/gdkdisplay-broadway.h b/gdk/broadway/gdkdisplay-broadway.h
index 69bd34a..51d59ae 100644
--- a/gdk/broadway/gdkdisplay-broadway.h
+++ b/gdk/broadway/gdkdisplay-broadway.h
@@ -57,6 +57,8 @@ struct _GdkBroadwayDisplay
   gpointer move_resize_data;
 
   GdkMonitor *monitor;
+
+  GHashTable *texture_cache;
 };
 
 struct _GdkBroadwayDisplayClass