diff --git a/src/hb-open-type-private.hh b/src/hb-open-type-private.hh
index 79e70b8cc..e5c4c0dc3 100644
--- a/src/hb-open-type-private.hh
+++ b/src/hb-open-type-private.hh
@@ -154,6 +154,19 @@ ASSERT_STATIC (Type::min_size + 1 <= sizeof (_Null##Type))
 #define Null(Type) Null<Type>()
 
 
+/*
+ * Dispatch
+ */
+
+template <typename Context, typename Return, unsigned int MaxDebugDepth>
+struct hb_dispatch_context_t
+{
+  static const unsigned int max_debug_depth = MaxDebugDepth;
+  typedef Return return_t;
+  template <typename T, typename F>
+  inline bool may_dispatch (const T *obj, const F *format) { return true; }
+};
+
 
 /*
  * Sanitize
@@ -174,11 +187,16 @@ ASSERT_STATIC (Type::min_size + 1 <= sizeof (_Null##Type))
 #define HB_SANITIZE_MAX_EDITS 100
 #endif
 
-struct hb_sanitize_context_t
+struct hb_sanitize_context_t :
+       hb_dispatch_context_t<hb_sanitize_context_t, bool, HB_DEBUG_SANITIZE>
 {
+  inline hb_sanitize_context_t (void) :
+	debug_depth (0),
+	start (NULL), end (NULL),
+	writable (false), edit_count (0),
+	blob (NULL) {}
+
   inline const char *get_name (void) { return "SANITIZE"; }
-  static const unsigned int max_debug_depth = HB_DEBUG_SANITIZE;
-  typedef bool return_t;
   template <typename T, typename F>
   inline bool may_dispatch (const T *obj, const F *format)
   { return format->sanitize (this); }
@@ -295,7 +313,7 @@ template <typename Type>
 struct Sanitizer
 {
   static hb_blob_t *sanitize (hb_blob_t *blob) {
-    hb_sanitize_context_t c[1] = {{0, NULL, NULL, false, 0, NULL}};
+    hb_sanitize_context_t c[1];
     bool sane;
 
     /* TODO is_sane() stuff */
diff --git a/src/hb-ot-layout-gsubgpos-private.hh b/src/hb-ot-layout-gsubgpos-private.hh
index 6cf1ffca7..65e39a607 100644
--- a/src/hb-ot-layout-gsubgpos-private.hh
+++ b/src/hb-ot-layout-gsubgpos-private.hh
@@ -46,14 +46,11 @@ namespace OT {
 	(&c->debug_depth, c->get_name (), this, HB_FUNC, \
 	 "");
 
-struct hb_closure_context_t
+struct hb_closure_context_t :
+       hb_dispatch_context_t<hb_closure_context_t, hb_void_t, HB_DEBUG_CLOSURE>
 {
   inline const char *get_name (void) { return "CLOSURE"; }
-  static const unsigned int max_debug_depth = HB_DEBUG_CLOSURE;
-  typedef hb_void_t return_t;
   typedef return_t (*recurse_func_t) (hb_closure_context_t *c, unsigned int lookup_index);
-  template <typename T, typename F>
-  inline bool may_dispatch (const T *obj, const F *format) { return true; }
   template <typename T>
   inline return_t dispatch (const T &obj) { obj.closure (this); return HB_VOID; }
   static return_t default_return_value (void) { return HB_VOID; }
@@ -98,13 +95,10 @@ struct hb_closure_context_t
 	(&c->debug_depth, c->get_name (), this, HB_FUNC, \
 	 "%d glyphs", c->len);
 
-struct hb_would_apply_context_t
+struct hb_would_apply_context_t :
+       hb_dispatch_context_t<hb_would_apply_context_t, bool, HB_DEBUG_WOULD_APPLY>
 {
   inline const char *get_name (void) { return "WOULD_APPLY"; }
-  static const unsigned int max_debug_depth = HB_DEBUG_WOULD_APPLY;
-  typedef bool return_t;
-  template <typename T, typename F>
-  inline bool may_dispatch (const T *obj, const F *format) { return true; }
   template <typename T>
   inline return_t dispatch (const T &obj) { return obj.would_apply (this); }
   static return_t default_return_value (void) { return false; }
@@ -138,14 +132,11 @@ struct hb_would_apply_context_t
 	(&c->debug_depth, c->get_name (), this, HB_FUNC, \
 	 "");
 
-struct hb_collect_glyphs_context_t
+struct hb_collect_glyphs_context_t :
+       hb_dispatch_context_t<hb_collect_glyphs_context_t, hb_void_t, HB_DEBUG_COLLECT_GLYPHS>
 {
   inline const char *get_name (void) { return "COLLECT_GLYPHS"; }
-  static const unsigned int max_debug_depth = HB_DEBUG_COLLECT_GLYPHS;
-  typedef hb_void_t return_t;
   typedef return_t (*recurse_func_t) (hb_collect_glyphs_context_t *c, unsigned int lookup_index);
-  template <typename T, typename F>
-  inline bool may_dispatch (const T *obj, const F *format) { return true; }
   template <typename T>
   inline return_t dispatch (const T &obj) { obj.collect_glyphs (this); return HB_VOID; }
   static return_t default_return_value (void) { return HB_VOID; }
@@ -232,14 +223,14 @@ struct hb_collect_glyphs_context_t
 #define HB_DEBUG_GET_COVERAGE (HB_DEBUG+0)
 #endif
 
+/* XXX Can we remove this? */
+
 template <typename set_t>
-struct hb_add_coverage_context_t
+struct hb_add_coverage_context_t :
+       hb_dispatch_context_t<hb_add_coverage_context_t<set_t>, const Coverage &, HB_DEBUG_GET_COVERAGE>
 {
   inline const char *get_name (void) { return "GET_COVERAGE"; }
-  static const unsigned int max_debug_depth = HB_DEBUG_GET_COVERAGE;
   typedef const Coverage &return_t;
-  template <typename T, typename F>
-  inline bool may_dispatch (const T *obj, const F *format) { return true; }
   template <typename T>
   inline return_t dispatch (const T &obj) { return obj.get_coverage (); }
   static return_t default_return_value (void) { return Null(Coverage); }
@@ -269,7 +260,8 @@ struct hb_add_coverage_context_t
 	 "idx %d gid %u lookup %d", \
 	 c->buffer->idx, c->buffer->cur().codepoint, (int) c->lookup_index);
 
-struct hb_apply_context_t
+struct hb_apply_context_t :
+       hb_dispatch_context_t<hb_apply_context_t, bool, HB_DEBUG_APPLY>
 {
   struct matcher_t
   {
@@ -449,11 +441,7 @@ struct hb_apply_context_t
 
 
   inline const char *get_name (void) { return "APPLY"; }
-  static const unsigned int max_debug_depth = HB_DEBUG_APPLY;
-  typedef bool return_t;
   typedef return_t (*recurse_func_t) (hb_apply_context_t *c, unsigned int lookup_index);
-  template <typename T, typename F>
-  inline bool may_dispatch (const T *obj, const F *format) { return true; }
   template <typename T>
   inline return_t dispatch (const T &obj) { return obj.apply (this); }
   static return_t default_return_value (void) { return false; }
diff --git a/src/hb-ot-layout.cc b/src/hb-ot-layout.cc
index 1a6fb15ee..275a960d5 100644
--- a/src/hb-ot-layout.cc
+++ b/src/hb-ot-layout.cc
@@ -28,6 +28,7 @@
  * Google Author(s): Behdad Esfahbod
  */
 
+#include "hb-open-type-private.hh"
 #include "hb-ot-layout-private.hh"
 
 #include "hb-ot-layout-gdef-table.hh"
@@ -925,13 +926,10 @@ apply_backward (OT::hb_apply_context_t *c,
   return ret;
 }
 
-struct hb_apply_forward_context_t
+struct hb_apply_forward_context_t :
+       OT::hb_dispatch_context_t<hb_apply_forward_context_t, bool, HB_DEBUG_APPLY>
 {
   inline const char *get_name (void) { return "APPLY_FWD"; }
-  static const unsigned int max_debug_depth = HB_DEBUG_APPLY;
-  typedef bool return_t;
-  template <typename T, typename F>
-  inline bool may_dispatch (const T *obj, const F *format) { return true; }
   template <typename T>
   inline return_t dispatch (const T &obj) { return apply_forward (c, obj, accel); }
   static return_t default_return_value (void) { return false; }