[serialize] Port to use object pool

Tested, but feels fragile :(.
This commit is contained in:
Behdad Esfahbod 2019-04-02 22:42:22 -07:00
parent 5efbc01174
commit 3305a2cad2
2 changed files with 91 additions and 55 deletions

View File

@ -35,14 +35,17 @@ template <typename T, unsigned ChunkLen = 16>
struct hb_pool_t struct hb_pool_t
{ {
hb_pool_t () : next (nullptr) {} hb_pool_t () : next (nullptr) {}
~hb_pool_t () { fini (); }
~hb_pool_t () void fini ()
{ {
next = nullptr; next = nullptr;
+ hb_iter (chunks) + hb_iter (chunks)
| hb_apply ([] (chunk_t *_) { ::free (_); }) | hb_apply ([] (chunk_t *_) { ::free (_); })
; ;
chunks.fini ();
} }
T* alloc () T* alloc ()

View File

@ -1,6 +1,7 @@
/* /*
* Copyright © 2007,2008,2009,2010 Red Hat, Inc. * Copyright © 2007,2008,2009,2010 Red Hat, Inc.
* Copyright © 2012,2018 Google, Inc. * Copyright © 2012,2018 Google, Inc.
* Copyright © 2019 Facebook, Inc.
* *
* This is part of HarfBuzz, a text shaping library. * This is part of HarfBuzz, a text shaping library.
* *
@ -24,6 +25,7 @@
* *
* Red Hat Author(s): Behdad Esfahbod * Red Hat Author(s): Behdad Esfahbod
* Google Author(s): Behdad Esfahbod * Google Author(s): Behdad Esfahbod
* Facebook Author(s): Behdad Esfahbod
*/ */
#ifndef HB_SERIALIZE_HH #ifndef HB_SERIALIZE_HH
@ -32,6 +34,7 @@
#include "hb.hh" #include "hb.hh"
#include "hb-blob.hh" #include "hb-blob.hh"
#include "hb-map.hh" #include "hb-map.hh"
#include "hb-pool.hh"
/* /*
@ -73,22 +76,34 @@ struct hb_serialize_context_t
}; };
hb_vector_t<link_t> links; hb_vector_t<link_t> links;
object_t *next;
}; };
range_t snapshot () { range_t s = {head, tail} ; return s; } range_t snapshot () { range_t s = {head, tail} ; return s; }
hb_serialize_context_t (void *start_, unsigned int size) hb_serialize_context_t (void *start_, unsigned int size) :
start ((char *) start_),
end (start + size),
current (nullptr)
{ reset (); }
~hb_serialize_context_t () { fini (); }
void fini ()
{ {
this->start = (char *) start_; ++ hb_iter (packed)
this->end = this->start + size; | hb_apply ([] (object_t *_) { _->fini (); })
reset (); ;
packed.fini ();
this->packed_map.fini ();
while (current)
{
auto *_ = current;
current = current->next;
_->fini ();
} }
~hb_serialize_context_t () object_pool.fini ();
{
current.fini_deep ();
packed.fini_deep ();
packed_map.fini ();
} }
bool in_error () const { return !this->successful; } bool in_error () const { return !this->successful; }
@ -101,10 +116,8 @@ struct hb_serialize_context_t
this->tail = this->end; this->tail = this->end;
this->debug_depth = 0; this->debug_depth = 0;
this->current.reset (); fini ();
this->packed.reset (); this->packed.push (nullptr);
this->packed.push ()->head = this->end;
this->packed_map.reset ();
} }
bool propagate_error (bool e) bool propagate_error (bool e)
@ -128,7 +141,7 @@ struct hb_serialize_context_t
this->start, this->end, this->start, this->end,
(unsigned long) (this->end - this->start)); (unsigned long) (this->end - this->start));
assert (!current.length); assert (!current);
return push<Type> (); return push<Type> ();
} }
void end_serialize () void end_serialize ()
@ -139,9 +152,10 @@ struct hb_serialize_context_t
(unsigned) (this->head - this->start), (unsigned) (this->head - this->start),
this->successful ? "successful" : "UNSUCCESSFUL"); this->successful ? "successful" : "UNSUCCESSFUL");
/* TODO Propagate errors. */ propagate_error (packed, packed_map);
assert (current.length == 1); if (unlikely (!current)) return;
assert (!current->next);
/* Only "pack" if there exist other objects... Otherwise, don't bother. /* Only "pack" if there exist other objects... Otherwise, don't bother.
* Saves a move. */ * Saves a move. */
@ -150,55 +164,69 @@ struct hb_serialize_context_t
pop_pack (); pop_pack ();
link (); resolve_links ();
} }
template <typename Type = void> template <typename Type = void>
Type *push () Type *push ()
{ {
object_t obj; object_t *obj = object_pool.alloc ();
obj.head = head; if (unlikely (!obj))
obj.tail = tail; propagate_error (false);
current.push (obj); else
{
obj->head = head;
obj->tail = tail;
obj->next = current;
current = obj;
}
return start_embed<Type> (); return start_embed<Type> ();
} }
void pop_discard () void pop_discard ()
{ {
revert (current.pop ()); object_t *obj = current;
if (unlikely (!obj)) return;
current = current->next;
revert (*obj);
object_pool.free (obj);
} }
objidx_t pop_pack () objidx_t pop_pack ()
{ {
object_t obj = current.pop (); object_t *obj = current;
obj.tail = head; if (unlikely (!obj)) return 0;
unsigned len = obj.tail - obj.head; current = current->next;
obj->tail = head;
obj->next = nullptr;
unsigned len = obj->tail - obj->head;
if (!len) if (!len)
{
assert (!obj->links.length);
return 0; return 0;
}
objidx_t objidx = packed_map.get (&obj); objidx_t objidx = packed_map.get (obj);
if (objidx) if (objidx)
{ {
obj.fini (); obj->fini ();
return objidx; return objidx;
} }
tail -= len; tail -= len;
memmove (tail, obj.head, len); memmove (tail, obj->head, len);
head = obj.head; head = obj->head;
obj.head = tail; obj->head = tail;
obj.tail = tail + len; obj->tail = tail + len;
object_t *key = packed.push (hb_move (obj)); packed.push (obj);
/* TODO Handle error. */
if (unlikely (packed.in_error ())) if (unlikely (packed.in_error ()))
return 0; return 0;
objidx = packed.length - 1; objidx = packed.length - 1;
if (0) // XXX Ouch. Our hashmap becomes invalid if packed resizes! packed_map.set (obj, objidx);
packed_map.set (key, objidx);
return objidx; return objidx;
} }
@ -215,12 +243,15 @@ struct hb_serialize_context_t
void discard_stale_objects () void discard_stale_objects ()
{ {
while (packed.length > 1 && while (packed.length > 1 &&
packed.tail ().head < tail) packed.tail ()->head < tail)
{ {
packed_map.del (&packed.tail ()); packed_map.del (packed.tail ());
assert (!packed.tail ()->next);
packed.tail ()->fini ();
packed.pop (); packed.pop ();
} }
assert (packed.tail ().head == tail); if (packed.length > 1)
assert (packed.tail ()->head == tail);
} }
template <typename T> template <typename T>
@ -231,34 +262,33 @@ struct hb_serialize_context_t
if (!objidx) if (!objidx)
return; return;
assert (current.length); assert (current);
assert (current.tail ().head <= (const char *) &ofs); assert (current->head <= (const char *) &ofs);
if (!base) if (!base)
base = current.tail ().head; base = current->head;
else else
assert (current.tail ().head <= (const char *) base); assert (current->head <= (const char *) base);
/* FUCK. Check ofs lies within current object? */ auto& link = *current->links.push ();
auto& link = *current.tail ().links.push ();
link.is_wide = sizeof (T) == 4; link.is_wide = sizeof (T) == 4;
link.position = (const char *) &ofs - (const char *) base; link.position = (const char *) &ofs - (const char *) base;
link.bias = (const char *) base - current.tail ().head; link.bias = (const char *) base - current->head;
link.objidx = objidx; link.objidx = objidx;
} }
void link () void resolve_links ()
{ {
assert (!current.length); assert (!current);
for (auto obj_it = packed.iter (); obj_it; ++obj_it) for (auto obj_it = ++hb_iter (packed); obj_it; ++obj_it)
{ {
const object_t &parent = *obj_it; const object_t &parent = **obj_it;
for (auto link_it = parent.links.iter (); link_it; ++link_it) for (auto link_it = parent.links.iter (); link_it; ++link_it)
{ {
const object_t::link_t &link = *link_it; const object_t::link_t &link = *link_it;
const object_t &child = packed[link.objidx]; const object_t &child = *packed[link.objidx];
unsigned offset = (child.head - parent.head) - link.bias; unsigned offset = (child.head - parent.head) - link.bias;
if (link.is_wide) if (link.is_wide)
@ -277,7 +307,7 @@ struct hb_serialize_context_t
} }
} }
unsigned int length () const { return this->head - current.tail ().head; } unsigned int length () const { return this->head - current->head; }
void align (unsigned int alignment) void align (unsigned int alignment)
{ {
@ -380,11 +410,14 @@ struct hb_serialize_context_t
private: private:
/* Object memory pool. */
hb_pool_t<object_t> object_pool;
/* Stack of currently under construction objects. */ /* Stack of currently under construction objects. */
hb_vector_t<object_t> current; object_t *current;
/* Stack of packed objects. Object 0 is always nil object. */ /* Stack of packed objects. Object 0 is always nil object. */
hb_vector_t<object_t> packed; hb_vector_t<object_t *> packed;
/* Map view of packed objects. */ /* Map view of packed objects. */
hb_hashmap_t<const object_t *, objidx_t, nullptr, 0> packed_map; hb_hashmap_t<const object_t *, objidx_t, nullptr, 0> packed_map;