[cplusplus] Add hb-cplusplus.hh

Fixes https://github.com/harfbuzz/harfbuzz/issues/2152

src/Makefile.sources

@@ -224,6 +224,7 @@ HB_BASE_headers = \
 	hb-blob.h \
 	hb-buffer.h \
 	hb-common.h \
+	hb-cplusplus.hh \
 	hb-deprecated.h \
 	hb-draw.h \
 	hb-face.h \

src/hb-cplusplus.hh

@@ -0,0 +1,133 @@
+/*
+ * Copyright © 2022 Behdad Esfahbod
+ *
+ *  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.
+ */
+
+#ifndef HB_CPLUSPLUS_HH
+#define HB_CPLUSPLUS_HH
+
+#include "hb.h"
+
+HB_BEGIN_DECLS
+HB_END_DECLS
+
+#ifdef __cplusplus
+
+#include <utility>
+
+#if 0
+#if !(__cplusplus >= 201103L)
+#error "HarfBuzz C++ helpers require C++11"
+#endif
+#endif
+
+namespace hb {
+
+
+template <typename T>
+struct vtable;
+
+template <typename T>
+struct shared_ptr
+{
+  using v = vtable<T>;
+
+  explicit shared_ptr (T *p = nullptr) : p (p) {}
+  shared_ptr (const shared_ptr &o) : p (v::reference (o.p)) {}
+  shared_ptr (shared_ptr &&o) : p (o.p) { o.p = nullptr; }
+  shared_ptr& operator = (const shared_ptr &o) { if (p != o.p) { destroy (); p = o.p; reference (); } return *this; }
+  shared_ptr& operator = (shared_ptr &&o) { destroy (); p = o.p; o.p = nullptr; return *this; }
+  ~shared_ptr () { v::destroy (p); }
+
+  T* get() const { return p; }
+
+  void swap (shared_ptr &o) { std::swap (p, o.p); }
+  friend void swap (shared_ptr &a, shared_ptr &b) { std::swap (a.p, b.p); }
+
+  operator T * () const { return p; }
+  T& operator * () const { return *get (); }
+  T* operator -> () const { return get (); }
+  operator bool () { return p; }
+  bool operator == (const shared_ptr &o) { return p == o.p; }
+  bool operator != (const shared_ptr &o) { return p != o.p; }
+
+  static T* get_empty() { return v::get_empty (); }
+  void reference() { v::reference (p); }
+  void destroy() { v::destroy (p); }
+  void set_user_data (hb_user_data_key_t *key,
+		      void *value,
+		      hb_destroy_func_t destroy,
+		      hb_bool_t replace) { v::set_user_data (p, key, value, destroy, replace); } 
+  void * get_user_data (hb_user_data_key_t *key) { return v::get_user_data (p, key); }
+
+  private:
+  T *p;
+};
+
+template <typename T,
+	  T * (*_get_empty) (void),
+	  T * (*_reference) (T *),
+	  void (*_destroy) (T *),
+	  hb_bool_t (*_set_user_data) (T *,
+				       hb_user_data_key_t *,
+				       void *,
+				       hb_destroy_func_t,
+				       hb_bool_t),
+	  void * (*_get_user_data) (T *,
+				    hb_user_data_key_t *)>
+struct vtable_t
+{
+  static constexpr auto get_empty = _get_empty;
+  static constexpr auto reference = _reference;
+  static constexpr auto destroy = _destroy;
+  static constexpr auto set_user_data = _set_user_data;
+  static constexpr auto get_user_data = _get_user_data;
+};
+
+#define HB_DEFINE_VTABLE(name) \
+	template<> \
+	struct vtable<hb_##name##_t> \
+	     : vtable_t<hb_##name##_t, \
+			&hb_##name##_get_empty, \
+			&hb_##name##_reference, \
+			&hb_##name##_destroy, \
+			&hb_##name##_set_user_data, \
+			&hb_##name##_get_user_data> {}
+
+HB_DEFINE_VTABLE (buffer);
+HB_DEFINE_VTABLE (blob);
+HB_DEFINE_VTABLE (face);
+HB_DEFINE_VTABLE (font);
+HB_DEFINE_VTABLE (font_funcs);
+HB_DEFINE_VTABLE (map);
+HB_DEFINE_VTABLE (set);
+HB_DEFINE_VTABLE (shape_plan);
+HB_DEFINE_VTABLE (unicode_funcs);
+
+#undef HB_DEFINE_VTABLE
+
+
+} // namespace hb
+
+#endif /* __cplusplus */
+
+#endif /* HB_CPLUSPLUS_HH */

src/meson.build

@@ -227,6 +227,7 @@ hb_base_headers = files(
   'hb-blob.h',
   'hb-buffer.h',
   'hb-common.h',
+  'hb-cplusplus.hh',
   'hb-deprecated.h',
   'hb-draw.h',
   'hb-face.h',

src/test-map.cc

@@ -20,7 +20,6 @@
  * 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.
- *
  */
 
 #include "hb.hh"

src/test-set.cc

@@ -20,13 +20,11 @@
  * 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.
- *
  */
 
 #include "hb.hh"
 #include "hb-set.hh"
 
-
 int
 main (int argc, char **argv)
 {

test/api/test-c.c

@@ -24,7 +24,7 @@
  * Google Author(s): Behdad Esfahbod
  */
 
-/* This file tests that all headers can be included from .c files */
+/* This file tests that all headers can be included from C files */
 
 
 #ifdef HAVE_CONFIG_H

test/api/test-cplusplus.cc

@@ -1,5 +1,6 @@
 /*
  * Copyright © 2011  Google, Inc.
+ * Copyright © 2022  Behdad Esfahbod
  *
  *  This is part of HarfBuzz, a text shaping library.
  *
@@ -24,7 +25,86 @@
  * Google Author(s): Behdad Esfahbod
  */
 
-/* This file tests that all headers can be included from .cc files */
+/* This file tests that all headers can be included from C++ files,
+ * as well as test the C++ API. */
 
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
 
-#include "test-c.c"
+#include <hb.h>
+#include <hb-ot.h>
+#include <hb-aat.h>
+
+#ifdef HAVE_GLIB
+#include <hb-glib.h>
+#endif
+
+#ifdef HAVE_ICU
+#include <hb-icu.h>
+#endif
+
+#ifdef HAVE_FREETYPE
+#include <hb-ft.h>
+#endif
+
+#ifdef HAVE_UNISCRIBE
+#include <hb-uniscribe.h>
+#endif
+
+#ifdef HAVE_CORETEXT
+#include <hb-coretext.h>
+#endif
+
+
+/* Test C++ API. */
+
+#include "hb-cplusplus.hh"
+
+#include <cassert>
+#include <utility>
+
+int
+main ()
+{
+  hb_buffer_t *b = hb_buffer_create ();
+  hb::shared_ptr<hb_buffer_t> pb {b};
+
+  /* Test copy-construction. */
+  assert (bool (pb));
+  hb::shared_ptr<hb_buffer_t> pb2 {pb};
+  assert (bool (pb2));
+  assert (bool (pb));
+
+  /* Test move-construction. */
+  assert (bool (pb2));
+  hb::shared_ptr<hb_buffer_t> pb4 {std::move (pb2)};
+  assert (!bool (pb2));
+  assert (bool (pb4));
+
+  /* Test copy-assignment. */
+  hb::shared_ptr<hb_buffer_t> pb3;
+  assert (!bool (pb3));
+  pb3 = pb;
+  assert (bool (pb3));
+  assert (bool (pb));
+
+  /* Test move-assignment. */
+  assert (bool (pb));
+  pb2 = std::move (pb);
+  assert (!bool (pb));
+
+  pb.reference ();
+  pb.destroy ();
+
+  pb3.reference ();
+  pb3.destroy ();
+
+  pb3.swap (pb4);
+
+  hb_user_data_key_t key;
+  pb.set_user_data (&key, b, nullptr, true);
+  (void) pb.get_user_data (&key);
+
+  return pb == pb.get_empty () || pb == pb2;
+}