[moira.git] / server / cache.dc

/*
 *	$Header$
 *
 *	Copyright (C) 1989, 1990 by the Massachusetts Institute of Technology
 *	For copying and distribution information, please see the file
 *	<mit-copyright.h>.
 */

#ifndef lint
static char *rcsid_cache_dc = "$Header$";
#endif lint

#include <mit-copyright.h>
#include "query.h"
#include "mr_server.h"
EXEC SQL INCLUDE sqlca;


extern char *whoami, *strsave();
extern int ingres_errno, mr_errcode;


/*** NOTE **************************************************************
 *
 *    This code depends on each type starting with a unique letter.  If
 *    any new types are added to the system that begin with the same
 *    letter as one of the existing types:
 *		User
 *		List
 *		String
 *		Machine
 *		Cluster
 *		Filesystem
 *    then we will have to rework the code that only looks at the first
 *    letter of the types.
 *
 ***********************************************************************
 */

/* Cache parameters: */
#define CACHESIZE 101		/* number of cache slots */
#define NAMESZ 257		/* max size of a name */

struct item {
    char name[NAMESZ];
    char type[9];
    int nhash;
    int id;
    struct item *next;
    struct item *prev;
    struct item *trans;		/* keep track of transactions */
};

static struct item cachehead;
static int cachesize;

/* statistics counters */
int cachehits = 0, cachemisses = 0;


/* Name hash function. */

int hashname(name, type)
register char *name;
char *type;
{
    register int val = *type;

    while (*name)
      val = val<<5 - val + *name++ - '`';
    return(val);
}


/* Initialize the cache, flushing any old data, and report the statistics
 * if the cache was previously in use.
 */

flush_cache()
{
    register struct item *i;

    if (cachehits + cachemisses != 0)
      com_err(whoami, 0, "Flushing cache; %d hits, %d misses, %d%% hit rate",
	      cachehits, cachemisses,
	      (100 * cachehits) / (cachehits + cachemisses));
    else
      cachehead.next = cachehead.prev = &cachehead;
    cachehits = cachemisses = cachesize = 0;
    for (i = cachehead.next; i != &cachehead; i = i->next) {
	if (i->prev != &cachehead)
	  free(i->prev);
    }
    if (cachehead.prev != &cachehead)
      free(cachehead.prev);
    cachehead.next = cachehead.prev = &cachehead;
    cachehead.trans = (struct item *)NULL;
}


/* Do a name to ID translation.  id will be updated with the answer if
 * it is available, and as a side effect the cache is updated.
 */

int name_to_id(name, type, id)
char *name;
char *type;
int *id;
{
    register struct item *i, *t;
    EXEC SQL BEGIN DECLARE SECTION;
    char *iname;
    int j, rowcount;
    EXEC SQL END DECLARE SECTION;
    int h, ctr;

    h = hashname(name, type);
    for (i = cachehead.next; i != &cachehead; i = i->next) {
	if (i->nhash != h ||
	    strcmp(name, i->name) ||
	    strcasecmp(type, i->type))
	  continue;
	*id = i->id;
	cachehits++;
	i->next->prev = i->prev;
	i->prev->next = i->next;
	i->next = cachehead.next;
	i->prev = &cachehead;
	cachehead.next->prev = i;
	cachehead.next = i;
	return(MR_SUCCESS);
    }

    cachemisses++;
    iname = name;

    switch (*type) {
    case 'U':
    case 'u':
	EXEC SQL SELECT users_id INTO :j FROM users WHERE login=:iname;
	break;
    case 'L':
    case 'l':
	EXEC SQL SELECT list_id INTO :j FROM list WHERE name=:iname;
	break;
    case 'M':
    case 'm':
	EXEC SQL SELECT mach_id INTO :j FROM machine WHERE name=uppercase(:iname);
	break;
    case 'C':
    case 'c':
	EXEC SQL SELECT clu_id INTO :j FROM cluster WHERE name=:iname;
	break;
    case 'F':
    case 'f':
	EXEC SQL SELECT filsys_id INTO :j FROM filesys WHERE label=:iname;
	break;
    case 'S':
    case 's':
	EXEC SQL SELECT string_id INTO :j FROM strings WHERE string=:iname;
	break;
    default:
	return(MR_INTERNAL);
    }
    if (sqlca.sqlcode == 100)
      return(MR_NO_MATCH);
    if (sqlca.sqlerrd[2] > 1)
      return(MR_NOT_UNIQUE);
    if (sqlca.sqlcode != 0)
      return(MR_INGRES_ERR);
    *id = j;
    if (name[0] == '#' && !strcasecmp(type, "USER"))
      return(MR_SUCCESS);
    if (cachesize < CACHESIZE) {
	i = (struct item *) malloc(sizeof(struct item));
	cachesize++;
    } else {
	i = cachehead.prev;
	cachehead.prev = i->prev;
	i->prev->next = &cachehead;
    }
    strcpy(i->name, name);
    strcpy(i->type, type);
    i->nhash = h;
    i->id = j;
    i->next = cachehead.next;
    i->prev = &cachehead;
    cachehead.next->prev = i;
    cachehead.next = i;
    /* find the end of the transaction chain & add this item */
    for (t = &cachehead; t->trans && t != i; t = t->trans);
    if (t != i) {
	t->trans = i;
	i->trans = (struct item *)NULL;
    }
    return(MR_SUCCESS);
}


/* Perform an ID to name mapping.  name should be a pointer to a pointer to
 * malloc'ed data.  The buffer it refers to will be freed, and a new buffer
 * allocated with the answer.
 */

int id_to_name(id, type, name)
int id;
char *type;
char **name;
{
    register struct item *i;
    EXEC SQL BEGIN DECLARE SECTION;
    char iname[NAMESZ];
    int j, rowcount;
    EXEC SQL END DECLARE SECTION;
    int ctr;

    for (i = cachehead.next; i != &cachehead; i = i->next) {
	if (i->id != id || strcasecmp(type, i->type)) continue;
	free(*name);
	*name = strsave(i->name);
	cachehits++;
	i->next->prev = i->prev;
	i->prev->next = i->next;
	i->next = cachehead.next;
	i->prev = &cachehead;
	cachehead.next->prev = i;
	cachehead.next = i;
	return(MR_SUCCESS);
    }

    cachemisses++;
    j = id;

    switch (*type) {
    case 'U':
    case 'u':
	EXEC SQL SELECT login INTO :iname FROM users WHERE users_id=:j;
	break;
    case 'L':
    case 'l':
	EXEC SQL SELECT name INTO :iname FROM list WHERE list_id=:j;
	break;
    case 'M':
    case 'm':
	EXEC SQL SELECT name INTO :iname FROM machine WHERE mach_id=:j;
	break;
    case 'C':
    case 'c':
	EXEC SQL SELECT name INTO :iname FROM cluster WHERE clu_id=:j;
	break;
    case 'F':
    case 'f':
	EXEC SQL SELECT label INTO :iname FROM filesys WHERE filsys_id=:j;
	break;
    case 'S':
    case 's':
	EXEC SQL SELECT string INTO :iname FROM strings WHERE string_id=:j;
	break;
    default:
	return(MR_INTERNAL);
    }
    if (sqlca.sqlcode == 100) {
	free(*name);
	sprintf(iname, "#%d", j);
	*name = strsave(iname);
	return(MR_NO_MATCH);
    }
    if (sqlca.sqlerrd[2] > 1)
      return(MR_INTERNAL);
    if (sqlca.sqlcode != 0)
      return(MR_INGRES_ERR);
    free(*name);
    *name = strsave(strtrim(iname));
    if (**name == '#' && !strcasecmp(type, "USER"))
      return(MR_SUCCESS);
    if (cachesize < CACHESIZE) {
	i = (struct item *) malloc(sizeof(struct item));
	cachesize++;
    } else {
	i = cachehead.prev;
	cachehead.prev = i->prev;
	i->prev->next = &cachehead;
    }
    strcpy(i->name, *name);
    strcpy(i->type, type);
    i->nhash = hashname(*name, type);
    i->id = id;
    i->next = cachehead.next;
    i->prev = &cachehead;
    cachehead.next->prev = i;
    cachehead.next = i;
    /* find the end of the transaction chain & add this item */
    for (t = &cachehead; t->trans && t != i; t = t->trans);
    if (t != i) {
	t->trans = i;
	i->trans = (struct item *)NULL;
    }
    return(MR_SUCCESS);
}


/* Explicitly add something to the cache without doing a lookup in the
 * database.
 */

cache_entry(name, type, id)
char *name;
char *type;
int id;
{
    register struct item *i, *t;

    for (i = cachehead.next; i != &cachehead; i = i->next)
      if (i->id == id && !strcmp(i->type, type)) {
	  if (strcmp(i->name, name)) {
	      strcpy(i->name, name);
	      i->nhash = hashname(name, type);
	  }
	  return(MR_SUCCESS);
      }
    if (cachesize < CACHESIZE) {
	i = (struct item *) malloc(sizeof(struct item));
	cachesize++;
    } else {
	i = cachehead.prev;
	cachehead.prev = i->prev;
	i->prev->next = &cachehead;
    }
    strcpy(i->name, name);
    strcpy(i->type, type);
    i->nhash = hashname(name, type);
    i->id = id;
    i->next = cachehead.next;
    i->prev = &cachehead;
    cachehead.next->prev = i;
    cachehead.next = i;
    /* find the end of the transaction chain & add this item */
    for (t = &cachehead; t->trans && t != i; t = t->trans);
    if (t != i) {
	t->trans = i;
	i->trans = (struct item *)NULL;
    }
    return(MR_SUCCESS);
}


/* Flush something that may or may not already be in the cache. */

flush_name(name, type)
char *name;
char *type;
{
    int h;
    register struct item *i;

    h = hashname(name, type);

    for (i = cachehead.next; i != &cachehead; i = i->next) {
	if (!strcmp(name, i->name) && !strcasecmp(type, i->type)) {
	    cachesize--;
	    i->next->prev = i->prev;
	    i->prev->next = i->next;
	    free(i);
	    return(MR_SUCCESS);
	}
    }
}


/* Called when a transaction is committed to also commit any cache changes.
 * Just throws away the list of cache changes for this transaction.
 */

cache_commit()
{
    cachehead.trans = (struct item *)NULL;
}


/* Called whan a transaction is aborted to throw away any cache changes
 * from that transaction.
 */

cache_abort()
{
    register struct item *i, *t;

    for (i = cachehead.trans; i; i = t) {
	t = i->trans;
	flush_name(i->name, i->type);
    }
    cachehead.trans = (struct item *)NULL;
}
Commit	Line	Data
7de02494	1	/*
	2	* $Header$
	3	*
	4	* Copyright (C) 1989, 1990 by the Massachusetts Institute of Technology
	5	* For copying and distribution information, please see the file
	6	* <mit-copyright.h>.
	7	*/
	8
	9	#ifndef lint
	10	static char *rcsid_cache_dc = "$Header$";
	11	#endif lint
	12
	13	#include <mit-copyright.h>
	14	#include "query.h"
	15	#include "mr_server.h"
	16	EXEC SQL INCLUDE sqlca;
	17
a49e54ea	18
7de02494	19	extern char whoami, strsave();
	20	extern int ingres_errno, mr_errcode;
	21
	22
	23	/* NOTE ************************************************************
	24	*
	25	* This code depends on each type starting with a unique letter. If
	26	* any new types are added to the system that begin with the same
	27	* letter as one of the existing types:
	28	* User
	29	* List
	30	* String
	31	* Machine
	32	* Cluster
	33	* Filesystem
	34	* then we will have to rework the code that only looks at the first
	35	* letter of the types.
	36	*
	37	***********************************************************************
	38	*/
	39
	40	/* Cache parameters: */
	41	#define CACHESIZE 101 /* number of cache slots */
	42	#define NAMESZ 257 /* max size of a name */
	43
	44	struct item {
	45	char name[NAMESZ];
	46	char type[9];
	47	int nhash;
	48	int id;
	49	struct item *next;
	50	struct item *prev;
a49e54ea	51	struct item trans; / keep track of transactions */
7de02494	52	};
	53
	54	static struct item cachehead;
	55	static int cachesize;
	56
	57	/* statistics counters */
	58	int cachehits = 0, cachemisses = 0;
	59
	60
	61	/* Name hash function. */
	62
	63	int hashname(name, type)
	64	register char *name;
	65	char *type;
	66	{
	67	register int val = *type;
	68
	69	while (*name)
	70	val = val<<5 - val + *name++ - '`';
	71	return(val);
	72	}
	73
	74
	75	/* Initialize the cache, flushing any old data, and report the statistics
	76	* if the cache was previously in use.
	77	*/
	78
	79	flush_cache()
	80	{
	81	register struct item *i;
	82
	83	if (cachehits + cachemisses != 0)
	84	com_err(whoami, 0, "Flushing cache; %d hits, %d misses, %d%% hit rate",
	85	cachehits, cachemisses,
	86	(100 * cachehits) / (cachehits + cachemisses));
	87	else
	88	cachehead.next = cachehead.prev = &cachehead;
	89	cachehits = cachemisses = cachesize = 0;
	90	for (i = cachehead.next; i != &cachehead; i = i->next) {
	91	if (i->prev != &cachehead)
	92	free(i->prev);
	93	}
	94	if (cachehead.prev != &cachehead)
	95	free(cachehead.prev);
	96	cachehead.next = cachehead.prev = &cachehead;
a49e54ea	97	cachehead.trans = (struct item *)NULL;
7de02494	98	}
	99
	100
	101	/* Do a name to ID translation. id will be updated with the answer if
	102	* it is available, and as a side effect the cache is updated.
	103	*/
	104
	105	int name_to_id(name, type, id)
	106	char *name;
	107	char *type;
	108	int *id;
	109	{
a49e54ea	110	register struct item i, t;
7de02494	111	EXEC SQL BEGIN DECLARE SECTION;
	112	char *iname;
	113	int j, rowcount;
	114	EXEC SQL END DECLARE SECTION;
	115	int h, ctr;
	116
	117	h = hashname(name, type);
	118	for (i = cachehead.next; i != &cachehead; i = i->next) {
	119	if (i->nhash != h \|\|
	120	strcmp(name, i->name) \|\|
	121	strcasecmp(type, i->type))
	122	continue;
	123	*id = i->id;
	124	cachehits++;
	125	i->next->prev = i->prev;
	126	i->prev->next = i->next;
	127	i->next = cachehead.next;
	128	i->prev = &cachehead;
	129	cachehead.next->prev = i;
	130	cachehead.next = i;
	131	return(MR_SUCCESS);
	132	}
	133
	134	cachemisses++;
	135	iname = name;
	136
	137	switch (*type) {
	138	case 'U':
	139	case 'u':
	140	EXEC SQL SELECT users_id INTO :j FROM users WHERE login=:iname;
	141	break;
	142	case 'L':
	143	case 'l':
	144	EXEC SQL SELECT list_id INTO :j FROM list WHERE name=:iname;
	145	break;
	146	case 'M':
	147	case 'm':
a49e54ea	148	EXEC SQL SELECT mach_id INTO :j FROM machine WHERE name=uppercase(:iname);
7de02494	149	break;
	150	case 'C':
	151	case 'c':
	152	EXEC SQL SELECT clu_id INTO :j FROM cluster WHERE name=:iname;
	153	break;
	154	case 'F':
	155	case 'f':
	156	EXEC SQL SELECT filsys_id INTO :j FROM filesys WHERE label=:iname;
	157	break;
	158	case 'S':
	159	case 's':
	160	EXEC SQL SELECT string_id INTO :j FROM strings WHERE string=:iname;
	161	break;
	162	default:
	163	return(MR_INTERNAL);
	164	}
	165	if (sqlca.sqlcode == 100)
	166	return(MR_NO_MATCH);
	167	if (sqlca.sqlerrd[2] > 1)
	168	return(MR_NOT_UNIQUE);
	169	if (sqlca.sqlcode != 0)
	170	return(MR_INGRES_ERR);
	171	*id = j;
	172	if (name[0] == '#' && !strcasecmp(type, "USER"))
	173	return(MR_SUCCESS);
	174	if (cachesize < CACHESIZE) {
	175	i = (struct item *) malloc(sizeof(struct item));
	176	cachesize++;
	177	} else {
	178	i = cachehead.prev;
	179	cachehead.prev = i->prev;
	180	i->prev->next = &cachehead;
	181	}
	182	strcpy(i->name, name);
	183	strcpy(i->type, type);
	184	i->nhash = h;
	185	i->id = j;
	186	i->next = cachehead.next;
	187	i->prev = &cachehead;
	188	cachehead.next->prev = i;
	189	cachehead.next = i;
a49e54ea	190	/* find the end of the transaction chain & add this item */
	191	for (t = &cachehead; t->trans && t != i; t = t->trans);
	192	if (t != i) {
	193	t->trans = i;
	194	i->trans = (struct item *)NULL;
	195	}
7de02494	196	return(MR_SUCCESS);
	197	}
	198
	199
	200	/* Perform an ID to name mapping. name should be a pointer to a pointer to
	201	* malloc'ed data. The buffer it refers to will be freed, and a new buffer
	202	* allocated with the answer.
	203	*/
	204
	205	int id_to_name(id, type, name)
	206	int id;
	207	char *type;
	208	char **name;
	209	{
	210	register struct item *i;
	211	EXEC SQL BEGIN DECLARE SECTION;
	212	char iname[NAMESZ];
	213	int j, rowcount;
	214	EXEC SQL END DECLARE SECTION;
	215	int ctr;
	216
	217	for (i = cachehead.next; i != &cachehead; i = i->next) {
	218	if (i->id != id \|\| strcasecmp(type, i->type)) continue;
	219	free(*name);
	220	*name = strsave(i->name);
	221	cachehits++;
	222	i->next->prev = i->prev;
	223	i->prev->next = i->next;
	224	i->next = cachehead.next;
	225	i->prev = &cachehead;
	226	cachehead.next->prev = i;
	227	cachehead.next = i;
	228	return(MR_SUCCESS);
	229	}
	230
	231	cachemisses++;
	232	j = id;
	233
	234	switch (*type) {
	235	case 'U':
	236	case 'u':
	237	EXEC SQL SELECT login INTO :iname FROM users WHERE users_id=:j;
	238	break;
	239	case 'L':
	240	case 'l':
	241	EXEC SQL SELECT name INTO :iname FROM list WHERE list_id=:j;
	242	break;
	243	case 'M':
	244	case 'm':
	245	EXEC SQL SELECT name INTO :iname FROM machine WHERE mach_id=:j;
	246	break;
	247	case 'C':
	248	case 'c':
	249	EXEC SQL SELECT name INTO :iname FROM cluster WHERE clu_id=:j;
	250	break;
	251	case 'F':
	252	case 'f':
	253	EXEC SQL SELECT label INTO :iname FROM filesys WHERE filsys_id=:j;
	254	break;
	255	case 'S':
	256	case 's':
	257	EXEC SQL SELECT string INTO :iname FROM strings WHERE string_id=:j;
	258	break;
	259	default:
260	return(MR_INTERNAL);
261	}
262	if (sqlca.sqlcode == 100) {
263	free(*name);
264	sprintf(iname, "#%d", j);
265	*name = strsave(iname);
266	return(MR_NO_MATCH);
267	}
268	if (sqlca.sqlerrd[2] > 1)
269	return(MR_INTERNAL);
270	if (sqlca.sqlcode != 0)
271	return(MR_INGRES_ERR);
272	free(*name);
273	*name = strsave(strtrim(iname));
274	if (**name == '#' && !strcasecmp(type, "USER"))
275	return(MR_SUCCESS);
276	if (cachesize < CACHESIZE) {
277	i = (struct item *) malloc(sizeof(struct item));
278	cachesize++;
279	} else {
280	i = cachehead.prev;
281	cachehead.prev = i->prev;
282	i->prev->next = &cachehead;
283	}
284	strcpy(i->name, *name);
285	strcpy(i->type, type);
286	i->nhash = hashname(*name, type);
287	i->id = id;
288	i->next = cachehead.next;
289	i->prev = &cachehead;
290	cachehead.next->prev = i;
291	cachehead.next = i;
a49e54ea	292	/* find the end of the transaction chain & add this item */
	293	for (t = &cachehead; t->trans && t != i; t = t->trans);
	294	if (t != i) {
	295	t->trans = i;
	296	i->trans = (struct item *)NULL;
	297	}
7de02494	298	return(MR_SUCCESS);
	299	}
	300
	301
	302	/* Explicitly add something to the cache without doing a lookup in the
	303	* database.
	304	*/
	305
	306	cache_entry(name, type, id)
	307	char *name;
	308	char *type;
	309	int id;
	310	{
a49e54ea	311	register struct item i, t;
7de02494	312
7de02494	313	for (i = cachehead.next; i != &cachehead; i = i->next)
a49e54ea	314	if (i->id == id && !strcmp(i->type, type)) {
	315	if (strcmp(i->name, name)) {
	316	strcpy(i->name, name);
	317	i->nhash = hashname(name, type);
	318	}
	319	return(MR_SUCCESS);
	320	}
7de02494	321	if (cachesize < CACHESIZE) {
	322	i = (struct item *) malloc(sizeof(struct item));
	323	cachesize++;
	324	} else {
	325	i = cachehead.prev;
	326	cachehead.prev = i->prev;
	327	i->prev->next = &cachehead;
	328	}
	329	strcpy(i->name, name);
	330	strcpy(i->type, type);
	331	i->nhash = hashname(name, type);
	332	i->id = id;
	333	i->next = cachehead.next;
	334	i->prev = &cachehead;
	335	cachehead.next->prev = i;
	336	cachehead.next = i;
a49e54ea	337	/* find the end of the transaction chain & add this item */
	338	for (t = &cachehead; t->trans && t != i; t = t->trans);
	339	if (t != i) {
	340	t->trans = i;
	341	i->trans = (struct item *)NULL;
	342	}
7de02494	343	return(MR_SUCCESS);
	344	}
	345
	346
	347	/* Flush something that may or may not already be in the cache. */
	348
	349	flush_name(name, type)
	350	char *name;
	351	char *type;
	352	{
	353	int h;
	354	register struct item *i;
	355
	356	h = hashname(name, type);
	357
	358	for (i = cachehead.next; i != &cachehead; i = i->next) {
	359	if (!strcmp(name, i->name) && !strcasecmp(type, i->type)) {
	360	cachesize--;
	361	i->next->prev = i->prev;
	362	i->prev->next = i->next;
	363	free(i);
	364	return(MR_SUCCESS);
	365	}
	366	}
	367	}
a49e54ea	368
	369
	370	/* Called when a transaction is committed to also commit any cache changes.
	371	* Just throws away the list of cache changes for this transaction.
	372	*/
	373
	374	cache_commit()
	375	{
	376	cachehead.trans = (struct item *)NULL;
	377	}
	378
	379
	380	/* Called whan a transaction is aborted to throw away any cache changes
	381	* from that transaction.
	382	*/
	383
	384	cache_abort()
	385	{
	386	register struct item i, t;
	387
	388	for (i = cachehead.trans; i; i = t) {
	389	t = i->trans;
	390	flush_name(i->name, i->type);
	391	}
	392	cachehead.trans = (struct item *)NULL;
	393	}