/*
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 *  Jabber
 *  Copyright (C) 1998-1999 The Jabber Team http://jabber.org/
 *  
 *  2/27/00:3am, random plans by jer
 *  
 *  ok based on gprof, we really need some innovation here... my thoughs are this:
 *  
 *  most things are strings, so have a string-based true-blue garbage collector
 *  one big global hash containing all the strings created by any pstrdup, returning const char *
 *  a refcount on each string block
 *  when a pool is freed, it moves down the refcount
 *  garbage collector collects pools on the free stack, and runs through the hash for unused strings
 *  j_strcmp can check for == (if they are both from a pstrdup)
 *  
 *  let's see... this would change:
 *  pstrdup: do a hash lookup, success=return, fail=pmalloc & hash put
 *  pool_free: 
 *  
 *  
 *  
 *  
 *  
 */

#include "libxode.h"

#ifdef POOL_DEBUG
int pool__total = 0;
int pool__ltotal = 0;
HASHTABLE pool__disturbed = NULL;
void *_pool__malloc(size_t size)
{
    pool__total++;
    return malloc(size);
}
void _pool__free(void *block)
{
    pool__total--;
    free(block);
}
#else
#define _pool__malloc malloc
#define _pool__free free
#endif


/* make an empty pool */
pool _pool_new(char *zone)
{
    pool p;
    while((p = _pool__malloc(sizeof(_pool))) == NULL) sleep(1);
    p->cleanup = NULL;
    p->heap = NULL;
    p->size = 0;

#ifdef POOL_DEBUG
    p->lsize = -1;
    p->zone[0] = '\0';
    strcat(p->zone,zone);
    sprintf(p->name,"%X",p);

    if(pool__disturbed == NULL)
	pool__disturbed = ghash_create(POOL_DEBUG,(KEYHASHFUNC)str_hash_code,(KEYCOMPAREFUNC)j_strcmp);
    ghash_put(pool__disturbed,p->name,p);
#endif

    return p;
}

/* free a heap */
void _pool_heap_free(void *arg)
{
    struct pheap *h = (struct pheap *)arg;

    _pool__free(h->block);
    _pool__free(h);
}

/* mem should always be freed last */
void _pool_cleanup_append(pool p, struct pfree *pf)
{
    struct pfree *cur;

    if(p->cleanup == NULL)
    {
	p->cleanup = pf;
	return;
    }

    /* fast forward to end of list */
    for(cur = p->cleanup; cur->next != NULL; cur = cur->next);

    cur->next = pf;
}

/* create a cleanup tracker */
struct pfree *_pool_free(pool p, pool_cleaner f, void *arg)
{
    struct pfree *ret;

    /* make the storage for the tracker */
    while((ret = _pool__malloc(sizeof(struct pfree))) == NULL) sleep(1);
    ret->f = f;
    ret->arg = arg;
    ret->next = NULL;

    return ret;
}

/* create a heap and make sure it get's cleaned up */
struct pheap *_pool_heap(pool p, int size)
{
    struct pheap *ret;
    struct pfree *clean;

    /* make the return heap */
    while((ret = _pool__malloc(sizeof(struct pheap))) == NULL) sleep(1);
    while((ret->block = _pool__malloc(size)) == NULL) sleep(1);
    ret->size = size;
    p->size += size;
    ret->used = 0;

    /* append to the cleanup list */
    clean = _pool_free(p, _pool_heap_free, (void *)ret);
    clean->heap = ret; /* for future use in finding used mem for pstrdup */
    _pool_cleanup_append(p, clean);

    return ret;
}

pool _pool_new_heap(int size, char *zone)
{
    pool p;
    p = _pool_new(zone);
    p->heap = _pool_heap(p,size);
    return p;
}

void *pmalloc(pool p, int size)
{
    void *block;

    if(p == NULL)
    {
	fprintf(stderr,"Memory Leak! [pmalloc received NULL pool, unable to track allocation, exiting]\n");
	abort();
    }

    /* if there is no heap for this pool or it's a big request, just raw, I like how we clean this :) */
    if(p->heap == NULL || size > (p->heap->size / 2))
    {
	while((block = _pool__malloc(size)) == NULL) sleep(1);
	p->size += size;
	_pool_cleanup_append(p, _pool_free(p, _pool__free, block));
	return block;
    }

    /* we have to preserve boundaries, long story :) */
    if(size >= 4)
	while(p->heap->used&7) p->heap->used++;

    /* if we don't fit in the old heap, replace it */
    if(size > (p->heap->size - p->heap->used))
	p->heap = _pool_heap(p, p->heap->size);

    /* the current heap has room */
    block = (char *)p->heap->block + p->heap->used;
    p->heap->used += size;
    return block;
}

void *pmalloc_x(pool p, int size, char c)
{
   void* result = pmalloc(p, size);
   if (result != NULL)
	   memset(result, c, size);
   return result;
}  

/* easy safety utility (for creating blank mem for structs, etc) */
void *pmalloco(pool p, int size)
{
    void *block = pmalloc(p, size);
    memset(block, 0, size);
    return block;
}  

/* XXX efficient: move this to const char * and then loop throug the existing heaps to see if src is within a block in this pool */
char *pstrdup(pool p, const char *src)
{
    char *ret;

    if(src == NULL)
	return NULL;

    ret = pmalloc(p,strlen(src) + 1);
    strcpy(ret,src);

    return ret;
}

/* when move above, this one would actually return a new block */
char *pstrdupx(pool p, const char *src)
{
    return pstrdup(p, src);
}

int pool_size(pool p)
{
    if(p == NULL) return 0;

    return p->size;
}

void pool_free(pool p)
{
    struct pfree *cur, *stub;

    if(p == NULL) return;

    cur = p->cleanup;
    while(cur != NULL)
    {
	(*cur->f)(cur->arg);
	stub = cur->next;
	_pool__free(cur);
	cur = stub;
    }

#ifdef POOL_DEBUG
    ghash_remove(pool__disturbed,p->name);
#endif

    _pool__free(p);

}

/* public cleanup utils, insert in a way that they are run FIFO, before mem frees */
void pool_cleanup(pool p, pool_cleaner f, void *arg)
{
    struct pfree *clean;

    clean = _pool_free(p, f, arg);
    clean->next = p->cleanup;
    p->cleanup = clean;
}

#ifdef POOL_DEBUG
void debug_log(char *zone, const char *msgfmt, ...);
int _pool_stat(void *arg, const void *key, void *data)
{
    pool p = (pool)data;

    if(p->lsize == -1)
	debug_log("leak","%s: %X is a new pool",p->zone,p->name);
    else if(p->size > p->lsize)
	debug_log("leak","%s: %X grew %d",p->zone,p->name, p->size - p->lsize);
    else if((int)arg)
	debug_log("leak","%s: %X exists %d",p->zone,p->name, p->size);
    p->lsize = p->size;
    return 1;
}

void pool_stat(int full)
{
    ghash_walk(pool__disturbed,_pool_stat,(void *)full);
    if(pool__total != pool__ltotal)
	debug_log("leak","%d\ttotal missed mallocs",pool__total);
    pool__ltotal = pool__total;
    return;
}
#else
void pool_stat(int full)
{
    return;
}
#endif