dbcache.c

bonddb 是一个源于PostgreSQL封装包的对象。它是一个由C/C++编写的快速数据提取层应用软件

#include <glib.h>
#include <stdio.h>

#include "dbcache.h"
#include "dbtoliet.h"
#include "dbuniqueid.h"
#include "dbobject.h"
#include "dbuniqueid.h"
#include "dbbureaucrat.h"
#include "dbfield.h"
#include "dbsqlparse.h"
#include "debug.h"
#include "dbfilter.h"

/*static void db_toliet_freecache_element(DbCache * c);
static void db_toliet_blank_element(DbCache * c, gint num); */

static gint 
db_cache_createall(Object *obj)
	{
	g_assert(obj);
	if (obj->cache != NULL)
		db_cache_cleanup(obj);
	obj->cache = mem_alloc(sizeof(DbCache*)*(obj->num+1));
	memset(obj->cache,0,sizeof(DbCache*)*(obj->num+1));
	obj->numcache = obj->num;
	
	return 0;
	}

static gint
db_cache_expand(Object *obj)
	{
	gint ptrlen;
	void *ptr;
	if (obj->num < obj->numcache)
		return -1;
	obj->cache = mem_realloc(obj->cache,sizeof(DbCache*)*(obj->num+1));
	ptr = obj->cache;
	(char*)ptr += obj->numcache*sizeof(DbCache*);
	ptrlen = (sizeof(DbCache*)*(obj->num)) - (sizeof(DbCache*)*(obj->numcache));
	memset(ptr,0,ptrlen);
	obj->numcache = obj->num;

	return 0;
	}

static void
db_cache_freecache_element(DbCache * c)
   {
   gint i;
	
   for (i = 0; i < c->num; i++)
      {
      if (c->value[i] != NULL)
         mem_free(c->value[i]);
      }
   db_filter_free(c->filter);
	db_id_free(c->id);

	mem_free(c->value);
   mem_free(c->flags);
   mem_free(c);
   return ;
   }

static void
db_cache_blank_element(DbCache * c, gint num)
   {
   gint i;

   g_assert(c);

   c->num = num;

   if (num <= 0)
      num = 1;

   c->value = (gchar **) mem_alloc(sizeof(gchar *) * num);
   for (i = 0; i < num; i++)
      c->value[i] = NULL;

   c->origrow = -1;
   c->id = NULL;
   c->state = OBJ_NEW;
   c->changed = FALSE;
   }

/**
 * db_cache_addtocache:
 * @obj: Database object
 *
 * Add to the cache index file a new entry, and return the newly created cache.  Do not 
 * free the variable returned.  You need to make sure you add an id and update the idindex
 * file after using this function. 
 *
 * Returns: Null on error else the newly created cache object.
 */
static DbCache *
db_cache_create(Object * obj)
   {
	DbCache *c;
   /* add an item to it */
   c = (DbCache *) mem_alloc(sizeof(DbCache));
   db_cache_blank_element(c, obj->numfield);
   /* create filter flags */
   c->flags = (gchar *) mem_alloc(sizeof(gchar) * (obj->numfield+1));
   memset(c->flags, 0, sizeof(gchar) * (obj->numfield+1));
   return c;
   }


/* =======================================================================================
 * External Code.
 */

/**
 * db_cache_moveto:
 * @obj: Database object
 * 
 * Replaces remberid() function.
 * Moves to the current row in the @obj, and if there isn't a cache item existing
 * it will create one.  If its a read source it will extract the UniqueIds (primary
 * keys or oid's).  Referencing is done on a row basis.
 * 
 * Returns: DbCache element for your current row.
 */
DbCache *
db_cache_moveto(Object *obj)
	{
	DbUniqueId *id;

	if (obj->cache == NULL)
		db_cache_createall(obj);
	else
	if (obj->numcache < obj->num)
		db_cache_expand(obj);
	if (obj->cache[obj->row] == NULL)
		{
		obj->cache [obj->row] = db_cache_create(obj);
		obj->cache [obj->row]->origrow = obj->row;
		id = db_id_remeberbyrow(obj, obj->row);
		obj->cache[obj->row]->filter = db_filter_create(TRUE, obj->row);
		obj->cache [obj->row]->id = id;
		if (db_id_isnewrecord(id) == FALSE)
			if (obj->cache [obj->row]->state == OBJ_NEW)
				obj->cache [obj->row]->state = OBJ_READ;
		}
	obj->currentcache = obj->cache[obj->row];
	/* Align the id's */
	db_id_syncid(obj);
	return obj->currentcache;
	}

/**
 * db_cache_isincache:
 * @obj: Database object
 *
 * Works out if the record you have currently selected is in cache or not.  This will take
 * the current UniqueId and row and see if there is data for this in cache.  
 *
 * Returns: %NULL if not in cache, else returns cached record.
 */
DbCache *
db_cache_isincache(Object * obj)
   {
   /* i suspect a bug lies here within */
   g_assert(obj);
   if (obj->cache == NULL)
      return NULL;
   /* the quick way... */
	if (obj->row >= obj->numcache)
		{
		errormsg("Referce to %s is %d outside of range of %d",obj->name,obj->row,obj->numcache);
		return NULL;
		}
	return obj->cache[obj->row];
	}

/**
 * db_cache_getvalue:
 * @obj: Database object
 * @cache: Single cache element
 * @field: Field name
 * @value: Pointer to a string that will have the returned string assigned to it.
 *
 * Get the value of a value in the cache.
 *
 * Returns: non-zero on failure
 */
gint
db_cache_getvalue(Object * obj, DbCache * cache, gchar * field, gchar * table, gchar ** value)
   {
   gint fieldpos;

   g_assert(cache);
   g_assert(field);
   g_assert(obj);
   *value = NULL;
	if (cache->value == NULL)
		{
		warningmsg("Nothing in here worth returning");
		return -1;
		}

   fieldpos = db_field_getpos(obj, field, table);
   if (fieldpos >= obj->numfield || fieldpos < 0)
      {
      errormsg("Invalid field %s, can not find a postiion for this.", field);
      return -1;
      }
   *value = cache->value[fieldpos];
	/* m.essage("got %s from cache. pos %d",*value,fieldpos); */

   return 0;
   }
/* Function for testing cache courption. */
/*
gint
dbtestcache(Object *obj)
	{
	gint i, j;
	for(i=0;i<obj->numcache;i++)
		if (obj->cache[i] != NULL)
			for(j=0;j<obj->cache[i]->num;j++)
				if (obj->cache[i]->value[j] != NULL)
					if (obj->cache[i]->value[j][0] == 226 || obj->cache[i]->value[j][0] == '