[mime-data] Allow embedding of arbitrary mime-types.

Use the surface user-data array allow to store an arbitrary set of
alternate image representations keyed by an interned string (which
ensures that it has a unique key in the user-visible namespace).

Update the API to mirror that of cairo_surface_set_user_data() [i.e.
return a status indicator] and switch internal users of the mime-data to
the public functions.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/cairo-types-private.h b/src/cairo-types-private.h
index 12e1a20e..8bcbf9aa 100644
--- a/src/cairo-types-private.h
+++ b/src/cairo-types-private.h
@@ -52,6 +52,7 @@ typedef struct _cairo_gstate cairo_gstate_t;
 typedef struct _cairo_hash_entry cairo_hash_entry_t;
 typedef struct _cairo_hash_table cairo_hash_table_t;
 typedef struct _cairo_image_surface cairo_image_surface_t;
+typedef struct _cairo_mime_data cairo_mime_data_t;
 typedef struct _cairo_output_stream cairo_output_stream_t;
 typedef struct _cairo_paginated_surface_backend cairo_paginated_surface_backend_t;
 typedef struct _cairo_path_fixed cairo_path_fixed_t;
@@ -342,4 +343,10 @@ typedef enum _cairo_image_transparency {
     CAIRO_IMAGE_UNKNOWN
 } cairo_image_transparency_t;
 
+struct _cairo_mime_data {
+    unsigned char *data;
+    unsigned int length;
+    cairo_destroy_func_t destroy;
+};
+
 #endif /* CAIRO_TYPES_PRIVATE_H */