src/hb-object.hh - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2007  Chris Wilson
  * Copyright © 2009,2010  Red Hat, Inc.
  * Copyright © 2011,2012  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.
  *
  * Contributor(s):
  *	Chris Wilson <chris@chris-wilson.co.uk>
  * Red Hat Author(s): Behdad Esfahbod
  * Google Author(s): Behdad Esfahbod
  */

 #ifndef HB_OBJECT_HH
 #define HB_OBJECT_HH

 #include "hb.hh"
 #include "hb-atomic.hh"
 #include "hb-mutex.hh"
 #include "hb-vector.hh"


 /*
  * Lockable set
  */

 template <typename item_t, typename lock_t>
 struct hb_lockable_set_t
 {
   hb_vector_t<item_t> items;

   void init () { items.init (); }

   template <typename T>
   item_t *replace_or_insert (T v, lock_t &l, bool replace)
   {
     l.lock ();
     item_t *item = items.lsearch (v);
     if (item) {
       if (replace) {
 	item_t old = *item;
 	*item = v;
 	l.unlock ();
 	old.fini ();
       }
       else {
 	item = nullptr;
 	l.unlock ();
       }
     } else {
       item = items.push (v);
       l.unlock ();
     }
     return items.in_error () ? nullptr : item;
   }

   template <typename T>
   void remove (T v, lock_t &l)
   {
     l.lock ();
     item_t *item = items.lsearch (v);
     if (item)
     {
       item_t old = *item;
       *item = std::move (items.tail ());
       items.pop ();
       l.unlock ();
       old.fini ();
     } else {
       l.unlock ();
     }
   }

   template <typename T>
   bool find (T v, item_t *i, lock_t &l)
   {
     l.lock ();
     item_t *item = items.lsearch (v);
     if (item)
       *i = *item;
     l.unlock ();
     return !!item;
   }

   template <typename T>
   item_t *find_or_insert (T v, lock_t &l)
   {
     l.lock ();
     item_t *item = items.find (v);
     if (!item) {
       item = items.push (v);
     }
     l.unlock ();
     return item;
   }

   void fini (lock_t &l)
   {
     if (!items.length)
     {
       /* No need to lock. */
       items.fini ();
       return;
     }
     l.lock ();
     while (items.length)
     {
       item_t old = items.tail ();
       items.pop ();
       l.unlock ();
       old.fini ();
       l.lock ();
     }
     items.fini ();
     l.unlock ();
   }

 };


 /*
  * Reference-count.
  */

 struct hb_reference_count_t
 {
   mutable hb_atomic_int_t ref_count;

   void init (int v = 1) { ref_count = v; }
   int get_relaxed () const { return ref_count; }
   int inc () const { return ref_count.inc (); }
   int dec () const { return ref_count.dec (); }
   void fini () { ref_count = -0x0000DEAD; }

   bool is_inert () const { return !ref_count; }
   bool is_valid () const { return ref_count > 0; }
 };


 /* user_data */

 struct hb_user_data_array_t
 {
   struct hb_user_data_item_t {
     hb_user_data_key_t *key;
     void *data;
     hb_destroy_func_t destroy;

     bool operator == (const hb_user_data_key_t *other_key) const { return key == other_key; }
     bool operator == (const hb_user_data_item_t &other) const { return key == other.key; }

     void fini () { if (destroy) destroy (data); }
   };

   hb_mutex_t lock;
   hb_lockable_set_t<hb_user_data_item_t, hb_mutex_t> items;

   void init () { lock.init (); items.init (); }

   void fini () { items.fini (lock); lock.fini (); }

   bool set (hb_user_data_key_t *key,
 	    void *              data,
 	    hb_destroy_func_t   destroy,
 	    hb_bool_t           replace)
   {
     if (!key)
       return false;

     if (replace) {
       if (!data && !destroy) {
 	items.remove (key, lock);
 	return true;
       }
     }
     hb_user_data_item_t item = {key, data, destroy};
     bool ret = !!items.replace_or_insert (item, lock, (bool) replace);

     return ret;
   }

   void *get (hb_user_data_key_t *key)
   {
     hb_user_data_item_t item = {nullptr, nullptr, nullptr};

     return items.find (key, &item, lock) ? item.data : nullptr;
   }
 };


 /*
  * Object header
  */

 struct hb_object_header_t
 {
   hb_reference_count_t ref_count;
   mutable hb_atomic_int_t writable = 0;
   hb_atomic_ptr_t<hb_user_data_array_t> user_data;

   bool is_inert () const { return !ref_count.get_relaxed (); }
 };
 #define HB_OBJECT_HEADER_STATIC {}


 /*
  * Object
  */

 template <typename Type>
 static inline void hb_object_trace (const Type *obj, const char *function)
 {
   DEBUG_MSG (OBJECT, (void *) obj,
 	     "%s refcount=%d",
 	     function,
 	     obj ? obj->header.ref_count.get_relaxed () : 0);
 }

 template <typename Type, typename ...Ts>
 static inline Type *hb_object_create (Ts... ds)
 {
   Type *obj = (Type *) hb_calloc (1, sizeof (Type));

   if (unlikely (!obj))
     return obj;

   new (obj) Type (std::forward<Ts> (ds)...);

   hb_object_init (obj);
   hb_object_trace (obj, HB_FUNC);

   return obj;
 }
 template <typename Type>
 static inline void hb_object_init (Type *obj)
 {
   obj->header.ref_count.init ();
   obj->header.writable = true;
   obj->header.user_data.init ();
 }
 template <typename Type>
 static inline bool hb_object_is_valid (const Type *obj)
 {
   return likely (obj->header.ref_count.is_valid ());
 }
 template <typename Type>
 static inline bool hb_object_is_immutable (const Type *obj)
 {
   return !obj->header.writable;
 }
 template <typename Type>
 static inline void hb_object_make_immutable (const Type *obj)
 {
   obj->header.writable = false;
 }
 template <typename Type>
 static inline Type *hb_object_reference (Type *obj)
 {
   hb_object_trace (obj, HB_FUNC);
   if (unlikely (!obj || obj->header.is_inert ()))
     return obj;
   assert (hb_object_is_valid (obj));
   obj->header.ref_count.inc ();
   return obj;
 }
 template <typename Type>
 static inline bool hb_object_destroy (Type *obj)
 {
   hb_object_trace (obj, HB_FUNC);
   if (unlikely (!obj || obj->header.is_inert ()))
     return false;
   assert (hb_object_is_valid (obj));
   if (obj->header.ref_count.dec () != 1)
     return false;

   hb_object_fini (obj);

   if (!std::is_trivially_destructible<Type>::value)
     obj->~Type ();

   return true;
 }
 template <typename Type>
 static inline void hb_object_fini (Type *obj)
 {
   obj->header.ref_count.fini (); /* Do this before user_data */
   hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
   if (user_data)
   {
     user_data->fini ();
     hb_free (user_data);
     obj->header.user_data.set_relaxed (nullptr);
   }
 }
 template <typename Type>
 static inline bool hb_object_set_user_data (Type               *obj,
 					    hb_user_data_key_t *key,
 					    void *              data,
 					    hb_destroy_func_t   destroy,
 					    hb_bool_t           replace)
 {
   if (unlikely (!obj || obj->header.is_inert ()))
     return false;
   assert (hb_object_is_valid (obj));

 retry:
   hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
   if (unlikely (!user_data))
   {
     user_data = (hb_user_data_array_t *) hb_calloc (sizeof (hb_user_data_array_t), 1);
     if (unlikely (!user_data))
       return false;
     user_data->init ();
     if (unlikely (!obj->header.user_data.cmpexch (nullptr, user_data)))
     {
       user_data->fini ();
       hb_free (user_data);
       goto retry;
     }
   }

   return user_data->set (key, data, destroy, replace);
 }

 template <typename Type>
 static inline void *hb_object_get_user_data (Type               *obj,
 					     hb_user_data_key_t *key)
 {
   if (unlikely (!obj || obj->header.is_inert ()))
     return nullptr;
   assert (hb_object_is_valid (obj));
   hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
   if (!user_data)
     return nullptr;
   return user_data->get (key);
 }


 #endif /* HB_OBJECT_HH */
	/*
	* Copyright © 2007 Chris Wilson
	* Copyright © 2009,2010 Red Hat, Inc.
	* Copyright © 2011,2012 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.
	*
	* Contributor(s):
	* Chris Wilson <chris@chris-wilson.co.uk>
	* Red Hat Author(s): Behdad Esfahbod
	* Google Author(s): Behdad Esfahbod
	*/

	#ifndef HB_OBJECT_HH
	#define HB_OBJECT_HH

	#include "hb.hh"
	#include "hb-atomic.hh"
	#include "hb-mutex.hh"
	#include "hb-vector.hh"


	/*
	* Lockable set
	*/

	template <typename item_t, typename lock_t>
	struct hb_lockable_set_t
	{
	hb_vector_t<item_t> items;

	void init () { items.init (); }

	template <typename T>
	item_t *replace_or_insert (T v, lock_t &l, bool replace)
	{
	l.lock ();
	item_t *item = items.lsearch (v);
	if (item) {
	if (replace) {
	item_t old = *item;
	*item = v;
	l.unlock ();
	old.fini ();
	}
	else {
	item = nullptr;
	l.unlock ();
	}
	} else {
	item = items.push (v);
	l.unlock ();
	}
	return items.in_error () ? nullptr : item;
	}

	template <typename T>
	void remove (T v, lock_t &l)
	{
	l.lock ();
	item_t *item = items.lsearch (v);
	if (item)
	{
	item_t old = *item;
	*item = std::move (items.tail ());
	items.pop ();
	l.unlock ();
	old.fini ();
	} else {
	l.unlock ();
	}
	}

	template <typename T>
	bool find (T v, item_t *i, lock_t &l)
	{
	l.lock ();
	item_t *item = items.lsearch (v);
	if (item)
	i = item;
	l.unlock ();
	return !!item;
	}

	template <typename T>
	item_t *find_or_insert (T v, lock_t &l)
	{
	l.lock ();
	item_t *item = items.find (v);
	if (!item) {
	item = items.push (v);
	}
	l.unlock ();
	return item;
	}

	void fini (lock_t &l)
	{
	if (!items.length)
	{
	/* No need to lock. */
	items.fini ();
	return;
	}
	l.lock ();
	while (items.length)
	{
	item_t old = items.tail ();
	items.pop ();
	l.unlock ();
	old.fini ();
	l.lock ();
	}
	items.fini ();
	l.unlock ();
	}

	};


	/*
	* Reference-count.
	*/

	struct hb_reference_count_t
	{
	mutable hb_atomic_int_t ref_count;

	void init (int v = 1) { ref_count = v; }
	int get_relaxed () const { return ref_count; }
	int inc () const { return ref_count.inc (); }
	int dec () const { return ref_count.dec (); }
	void fini () { ref_count = -0x0000DEAD; }

	bool is_inert () const { return !ref_count; }
	bool is_valid () const { return ref_count > 0; }
	};


	/* user_data */

	struct hb_user_data_array_t
	{
	struct hb_user_data_item_t {
	hb_user_data_key_t *key;
	void *data;
	hb_destroy_func_t destroy;

	bool operator == (const hb_user_data_key_t *other_key) const { return key == other_key; }
	bool operator == (const hb_user_data_item_t &other) const { return key == other.key; }

	void fini () { if (destroy) destroy (data); }
	};

	hb_mutex_t lock;
	hb_lockable_set_t<hb_user_data_item_t, hb_mutex_t> items;

	void init () { lock.init (); items.init (); }

	void fini () { items.fini (lock); lock.fini (); }

	bool set (hb_user_data_key_t *key,
	void * data,
	hb_destroy_func_t destroy,
	hb_bool_t replace)
	{
	if (!key)
	return false;

	if (replace) {
	if (!data && !destroy) {
	items.remove (key, lock);
	return true;
	}
	}
	hb_user_data_item_t item = {key, data, destroy};
	bool ret = !!items.replace_or_insert (item, lock, (bool) replace);

	return ret;
	}

	void get (hb_user_data_key_t key)
	{
	hb_user_data_item_t item = {nullptr, nullptr, nullptr};

	return items.find (key, &item, lock) ? item.data : nullptr;
	}
	};


	/*
	* Object header
	*/

	struct hb_object_header_t
	{
	hb_reference_count_t ref_count;
	mutable hb_atomic_int_t writable = 0;
	hb_atomic_ptr_t<hb_user_data_array_t> user_data;

	bool is_inert () const { return !ref_count.get_relaxed (); }
	};
	#define HB_OBJECT_HEADER_STATIC {}


	/*
	* Object
	*/

	template <typename Type>
	static inline void hb_object_trace (const Type obj, const char function)
	{
	DEBUG_MSG (OBJECT, (void *) obj,
	"%s refcount=%d",
	function,
	obj ? obj->header.ref_count.get_relaxed () : 0);
	}

	template <typename Type, typename ...Ts>
	static inline Type *hb_object_create (Ts... ds)
	{
	Type obj = (Type ) hb_calloc (1, sizeof (Type));

	if (unlikely (!obj))
	return obj;

	new (obj) Type (std::forward<Ts> (ds)...);

	hb_object_init (obj);
	hb_object_trace (obj, HB_FUNC);

	return obj;
	}
	template <typename Type>
	static inline void hb_object_init (Type *obj)
	{
	obj->header.ref_count.init ();
	obj->header.writable = true;
	obj->header.user_data.init ();
	}
	template <typename Type>
	static inline bool hb_object_is_valid (const Type *obj)
	{
	return likely (obj->header.ref_count.is_valid ());
	}
	template <typename Type>
	static inline bool hb_object_is_immutable (const Type *obj)
	{
	return !obj->header.writable;
	}
	template <typename Type>
	static inline void hb_object_make_immutable (const Type *obj)
	{
	obj->header.writable = false;
	}
	template <typename Type>
	static inline Type hb_object_reference (Type obj)
	{
	hb_object_trace (obj, HB_FUNC);
	if (unlikely (!obj \|\| obj->header.is_inert ()))
	return obj;
	assert (hb_object_is_valid (obj));
	obj->header.ref_count.inc ();
	return obj;
	}
	template <typename Type>
	static inline bool hb_object_destroy (Type *obj)
	{
	hb_object_trace (obj, HB_FUNC);
	if (unlikely (!obj \|\| obj->header.is_inert ()))
	return false;
	assert (hb_object_is_valid (obj));
	if (obj->header.ref_count.dec () != 1)
	return false;

	hb_object_fini (obj);

	if (!std::is_trivially_destructible<Type>::value)
	obj->~Type ();

	return true;
	}
	template <typename Type>
	static inline void hb_object_fini (Type *obj)
	{
	obj->header.ref_count.fini (); /* Do this before user_data */
	hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
	if (user_data)
	{
	user_data->fini ();
	hb_free (user_data);
	obj->header.user_data.set_relaxed (nullptr);
	}
	}
	template <typename Type>
	static inline bool hb_object_set_user_data (Type *obj,
	hb_user_data_key_t *key,
	void * data,
	hb_destroy_func_t destroy,
	hb_bool_t replace)
	{
	if (unlikely (!obj \|\| obj->header.is_inert ()))
	return false;
	assert (hb_object_is_valid (obj));

	retry:
	hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
	if (unlikely (!user_data))
	{
	user_data = (hb_user_data_array_t *) hb_calloc (sizeof (hb_user_data_array_t), 1);
	if (unlikely (!user_data))
	return false;
	user_data->init ();
	if (unlikely (!obj->header.user_data.cmpexch (nullptr, user_data)))
	{
	user_data->fini ();
	hb_free (user_data);
	goto retry;
	}
	}

	return user_data->set (key, data, destroy, replace);
	}

	template <typename Type>
	static inline void hb_object_get_user_data (Type obj,
	hb_user_data_key_t *key)
	{
	if (unlikely (!obj \|\| obj->header.is_inert ()))
	return nullptr;
	assert (hb_object_is_valid (obj));
	hb_user_data_array_t *user_data = obj->header.user_data.get_acquire ();
	if (!user_data)
	return nullptr;
	return user_data->get (key);
	}


	#endif /* HB_OBJECT_HH */