Start adding a unified shaper access infrastructure

Add global shape_plan.  Unused so far.

src/hb-shaper-private.hh

diff --git a/src/hb-shaper-private.hh b/src/hb-shaper-private.hh
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+/*
+ * Copyright © 2012  Google, Inc.
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Google Author(s): Behdad Esfahbod
+ */
+
+#ifndef HB_SHAPER_PRIVATE_HH
+#define HB_SHAPER_PRIVATE_HH
+
+#include "hb-private.hh"
+
+typedef hb_bool_t hb_shape_func_t (hb_font_t          *font,
+				   hb_buffer_t        *buffer,
+				   const hb_feature_t *features,
+				   unsigned int        num_features);
+
+#define HB_SHAPER_IMPLEMENT(name) \
+	extern "C" HB_INTERNAL hb_shape_func_t _hb_##name##_shape;
+#include "hb-shaper-list.hh"
+#undef HB_SHAPER_IMPLEMENT
+
+/* For embedding in face / font / ... */
+struct hb_shaper_data_t {
+#define HB_SHAPER_IMPLEMENT(shaper) void *shaper;
+#include "hb-shaper-list.hh"
+#undef HB_SHAPER_IMPLEMENT
+};
+
+#define HB_NUM_SHAPERS (sizeof (hb_shaper_data_t) / sizeof (void *))
+
+/* Means: succeeded, but don't need to keep any data. */
+#define HB_SHAPER_DATA_SUCCEEDED ((void *) +1)
+
+/* Means: tried but failed to create. */
+#define HB_SHAPER_DATA_INVALID ((void *) -1)
+#define HB_SHAPER_DATA_IS_INVALID(data) ((void *) (data) == HB_SHAPER_DATA_INVALID)
+
+#define HB_SHAPER_DATA_TYPE(shaper, object)		struct hb_##shaper##_shaper_##object##_data_t
+#define HB_SHAPER_DATA(shaper, object)			((HB_SHAPER_DATA_TYPE(shaper, object) *) (object)->shaper_data.shaper)
+#define HB_SHAPER_DATA_GET_FUNC(shaper, object)		_hb_##shaper##_shaper_get_##object##_data
+#define HB_SHAPER_DATA_CREATE_FUNC(shaper, object)	_hb_##shaper##_shaper_##object##_data_create
+#define HB_SHAPER_DATA_DESTROY_FUNC(shaper, object)	_hb_##shaper##_shaper_##object##_data_destroy
+
+#define HB_SHAPER_DATA_PROTOTYPE(shaper, object) \
+	HB_SHAPER_DATA_TYPE (shaper, object); /* Type forward declaration. */ \
+	static inline HB_SHAPER_DATA_TYPE (shaper, object) * \
+	HB_SHAPER_DATA_GET_FUNC (shaper, object) (hb_##object##_t *object) \
+	{ return HB_SHAPER_DATA (shaper, object); } \
+	extern "C" HB_INTERNAL HB_SHAPER_DATA_TYPE (shaper, object) * \
+	HB_SHAPER_DATA_CREATE_FUNC (shaper, object) (hb_##object##_t *object); \
+	extern "C" HB_INTERNAL void \
+	HB_SHAPER_DATA_DESTROY_FUNC (shaper, object) (HB_SHAPER_DATA_TYPE (shaper, object) *data)
+
+#define HB_SHAPER_DATA_DESTROY(shaper, object) \
+	if (object->shaper_data.shaper && \
+	    object->shaper_data.shaper != HB_SHAPER_DATA_INVALID && \
+	    object->shaper_data.shaper != HB_SHAPER_DATA_SUCCEEDED) \
+	  HB_SHAPER_DATA_DESTROY_FUNC (shaper, object) (HB_SHAPER_DATA (shaper, object));
+
+
+#endif /* HB_SHAPER_PRIVATE_HH */