Re: How scaled_font private structures work ?

From 3e0270f6960f9d55835bfcb0761187156a9a6245 Mon Sep 17 00:00:00 2001
From: "Enrico Weigelt, metux IT consult" <[email protected]>
Date: Fri, 11 Dec 2015 12:04:36 +0100
Subject: [PATCH] drm/i915: fixed handling of private pointers in scaled_font
 objects

---
 src/drm/cairo-drm-i915-glyphs.c   | 33 +++++++++++++++++++++++++++++----
 src/drm/cairo-drm-i915-private.h  |  7 +++++++
 src/drm/cairo-drm-intel-private.h |  4 ++++
 3 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/src/drm/cairo-drm-i915-glyphs.c b/src/drm/cairo-drm-i915-glyphs.c
index 287eb87..01534ca 100644
--- a/src/drm/cairo-drm-i915-glyphs.c
+++ b/src/drm/cairo-drm-i915-glyphs.c
@@ -273,6 +273,22 @@ CLEANUP_SHADER:
     return status;
 }
 
+/* this is just a dummy to produce an unique address */
+static const char *_i915_scaled_font_key = "i915_scaled_font_t";
+
+/* destructor for the i915_scaled_font object */
+static void _i915_scaled_font_fini(
+    cairo_scaled_font_private_t *abstract_priv,
+    cairo_scaled_font_t* scaled_font)
+{
+    i915_scaled_font_private_t *i915_priv = cairo_container_of(abstract_priv, i915_scaled_font_private_t, base);
+
+    // FIXME: do we need to do something more ?
+
+    cairo_list_del(&i915_priv->base.link);
+    free(i915_priv);
+}
+
 cairo_int_status_t
 i915_surface_glyphs (void			*abstract_surface,
 		     cairo_operator_t		 op,
@@ -414,10 +430,19 @@ i915_surface_glyphs (void			*abstract_surface,
     device = i915_device (surface);
 
     _cairo_scaled_font_freeze_cache (scaled_font);
-    if (scaled_font->surface_private == NULL) {
-	scaled_font->surface_private = device;
-	scaled_font->surface_backend = surface->intel.drm.base.backend;
-	cairo_list_add (&scaled_font->link, &device->intel.fonts);
+
+    if (_cairo_scaled_font_find_private(scaled_font, _i915_scaled_font_key) == NULL) {
+	i915_scaled_font_private_t *priv = (i915_scaled_font_private_t*)malloc(sizeof(i915_scaled_font_private_t));
+
+	priv->device = device;
+	priv->backend = surface->intel.drm.base.backend;
+
+	_cairo_scaled_font_attach_private(
+		scaled_font,
+		&(priv->base),
+		_i915_scaled_font_key,
+		_i915_scaled_font_fini
+	);
     }
 
     memset (glyph_cache, 0, sizeof (glyph_cache));
diff --git a/src/drm/cairo-drm-i915-private.h b/src/drm/cairo-drm-i915-private.h
index 2e39b9b..5c13619 100644
--- a/src/drm/cairo-drm-i915-private.h
+++ b/src/drm/cairo-drm-i915-private.h
@@ -620,6 +620,7 @@ i915_fs_operand_pure_alpha (int pure)
 typedef struct i915_surface i915_surface_t;
 typedef struct i915_device i915_device_t;
 typedef struct i915_shader i915_shader_t;
+typedef struct i915_scaled_font_private i915_scaled_font_private_t;
 
 typedef void (*i915_add_rectangle_func_t) (const i915_shader_t *shader,
 					   int x, int y,
@@ -713,6 +714,12 @@ struct i915_device {
     uint8_t vbo_base[I915_VBO_SIZE];
 };
 
+struct i915_scaled_font_private {
+    cairo_scaled_font_private_t base;
+    i915_device_t *device;
+    const cairo_surface_backend_t *backend;
+};
+
 enum {
     CURRENT_SOURCE = 0x1,
     CURRENT_MASK = 0x2,
diff --git a/src/drm/cairo-drm-intel-private.h b/src/drm/cairo-drm-intel-private.h
index 4fd1b70..0fd0e10 100644
--- a/src/drm/cairo-drm-intel-private.h
+++ b/src/drm/cairo-drm-intel-private.h
@@ -168,6 +168,10 @@ typedef struct _intel_glyph {
     int width, height;
 } intel_glyph_t;
 
+typedef struct _intel_scaled_font {
+    cairo_scaled_font_private_t base;
+} intel_scaled_font_t;
+
 typedef struct _intel_gradient_cache {
     cairo_pattern_union_t pattern;
     intel_buffer_t buffer;
-- 
1.9.1