/** Basic query functionality
*/
void query(void *db, char **argv, int argc) {
int qargc;
void *rec = NULL;
wg_query *q;
wg_query_arg *arglist;
gint lock_id;
arglist = make_arglist(db, argv, argc, &qargc);
if(!arglist)
return;
if(!(lock_id = wg_start_read(db))) {
fprintf(stderr, "failed to get lock on database\n");
goto abrt1;
}
q = wg_make_query(db, NULL, 0, arglist, qargc);
if(!q)
goto abrt2;
/* printf("query col: %d type: %d\n", q->column, q->qtype); */
rec = wg_fetch(db, q);
while(rec) {
wg_print_record(db, (gint *) rec);
printf("\n");
rec = wg_fetch(db, q);
}
wg_free_query(db, q);
abrt2:
wg_end_read(db, lock_id);
abrt1:
free_arglist(db, arglist, qargc);
}
/** Print rows from database
*
*/
void selectdata(void *db, int howmany, int startingat) {
void *rec = wg_get_first_record(db);
int i, count;
for(i=0;i<startingat;i++){
if(rec == NULL) return;
rec=wg_get_next_record(db,rec);
}
count=0;
while(rec != NULL) {
wg_print_record(db, (gint *) rec);
printf("\n");
count++;
if(count == howmany) break;
rec=wg_get_next_record(db,rec);
}
return;
}
void run_demo(void* db) {
void *rec = NULL, *firstrec = NULL, *nextrec = NULL;
/* Pointers to a database record */
wg_int enc; /* Encoded data */
wg_int lock_id; /* Id of an acquired lock (for releasing it later) */
wg_int len;
int i;
int intdata, datedata, timedata;
char strbuf[80];
printf("********* Starting demo ************\n");
/* Begin by creating a simple record of 3 fields and fill it
* with integer data.
*/
printf("Creating first record.\n");
rec=wg_create_record(db, 3);
if (rec==NULL) {
printf("rec creation error.\n");
return;
}
/* Encode a field, checking for errors */
enc = wg_encode_int(db, 44);
if(enc==WG_ILLEGAL) {
printf("failed to encode an integer.\n");
return;
}
/* Negative return value shows that an error occurred */
if(wg_set_field(db, rec, 0, enc) < 0) {
printf("failed to store a field.\n");
return;
}
/* Skip error checking for the sake of brevity for the rest of fields */
enc = wg_encode_int(db, -199999);
wg_set_field(db, rec, 1, enc);
wg_set_field(db, rec, 2, wg_encode_int(db, 0));
/* Now examine the record we have created. Get record length,
* encoded value of each field, data type and decoded value.
*/
/* Negative return value shows an error. */
len = wg_get_record_len(db, rec);
if(len < 0) {
printf("failed to get record length.\n");
return;
}
printf("Size of created record at %p was: %d\n", rec, (int) len);
for(i=0; i<len; i++) {
printf("Reading field %d:", i);
enc = wg_get_field(db, rec, i);
if(wg_get_encoded_type(db, enc) != WG_INTTYPE) {
printf("data was of unexpected type.\n");
return;
}
intdata = wg_decode_int(db, enc);
/* No error checking here. All integers are valid. */
printf(" %d\n", intdata);
}
/* Fields can be erased by setting their value to 0 which always stands for NULL value. */
printf("Clearing field 1.\n");
wg_set_field(db, rec, 1, 0);
if(wg_get_field(db, rec, 1)==0) {
printf("Re-reading field 1 returned a 0 (NULL) field.\n");
} else {
printf("unexpected value \n");
return;
}
/* Fields can be updated with data of any type (the type is not fixed). */
printf("Updating field 0 to a floating-point number.\n");
enc = wg_encode_double(db, 56.9988);
wg_set_field(db, rec, 0, enc);
enc = wg_get_field(db, rec, 0);
if(wg_get_encoded_type(db, enc) == WG_DOUBLETYPE) {
printf("Re-reading field 0 returned %f.\n", wg_decode_double(db, enc));
} else {
printf("data was of unexpected type.\n");
return;
}
/* Create a next record. Let's assume we're in an environment where
* the database is used concurrently, so there's a need to use locking.
*/
printf("Creating second record.\n");
/* Lock id of 0 means that the operation failed */
lock_id = wg_start_write(db);
if(!lock_id) {
printf("failed to acquire lock.\n");
return;
}
/* Do the write operation we acquired the lock for. */
rec=wg_create_record(db, 6);
/* Failing to release the lock would be fatal to database operation. */
if(!wg_end_write(db, lock_id)) {
printf("failed to release lock.\n");
return;
}
if (!rec) {
printf("rec creation error.\n");
return;
}
/* Reading also requires locking./ */
lock_id = wg_start_read(db);
if(!lock_id) {
printf("failed to acquire lock.\n");
return;
}
/* Do our read operation... */
len = wg_get_record_len(db, rec);
/* ... and unlock immediately */
if(!wg_end_read(db, lock_id)) {
printf("failed to release lock.\n");
return;
}
if(len < 0) {
printf("failed to get record length.\n");
return;
}
printf("Size of created record at %p was: %d\n", rec, (int) len);
/* Let's find the first record in the database */
lock_id = wg_start_read(db);
firstrec = wg_get_first_record(db);
wg_end_read(db, lock_id);
if(!firstrec) {
printf("Failed to find first record.\n");
return;
}
printf("First record of database had address %p.\n", firstrec);
/* Let's check what the next record is to demonstrate scanning records. */
nextrec = firstrec;
lock_id = wg_start_read(db);
do {
nextrec = wg_get_next_record(db, nextrec);
if(nextrec)
printf("Next record had address %p.\n", nextrec);
} while(nextrec);
printf("Finished scanning database records.\n");
wg_end_read(db, lock_id);
/* Set fields to various values. Field 0 is not touched at all (un-
* initialized). Field 1 is set to point to another record.
*/
printf("Populating second record with data.\n");
/* Let's use the first record we found to demonstrate storing
* a link to a record in a field inside another record. */
lock_id = wg_start_write(db);
enc = wg_encode_record(db, firstrec);
wg_set_field(db, rec, 1, enc);
wg_end_write(db, lock_id);
/* Now set other fields to various data types. To keep the example shorter,
* the locking and unlocking operations are omitted (in real applications,
* this would be incorrect usage if concurrent access is expected).
*/
wg_set_field(db, rec, 2, wg_encode_str(db, "This is a char array", NULL));
wg_set_field(db, rec, 3, wg_encode_char(db, 'a'));
/* For time and date, we use current time in local timezone */
enc = wg_encode_date(db, wg_current_localdate(db));
if(enc==WG_ILLEGAL) {
printf("failed to encode date.\n");
return;
}
wg_set_field(db, rec, 4, enc);
enc = wg_encode_time(db, wg_current_localtime(db));
if(enc==WG_ILLEGAL) {
printf("failed to encode time.\n");
return;
}
wg_set_field(db, rec, 5, enc);
/* Now read and print all the fields. */
wg_print_record(db, (wg_int *) rec);
printf("\n");
/* Date and time can be handled together as a datetime object. */
datedata = wg_decode_date(db, wg_get_field(db, rec, 4));
timedata = wg_decode_time(db, wg_get_field(db, rec, 5));
wg_strf_iso_datetime(db, datedata, timedata, strbuf);
printf("Reading datetime: %s.\n", strbuf);
printf("Setting date and time to 2010-03-31, 12:59\n");
/* Update date and time to arbitrary values using wg_strp_iso_date/time */
wg_set_field(db, rec, 4,
wg_encode_date(db, wg_strp_iso_date(db, "2010-03-31")));
wg_set_field(db, rec, 5,
wg_encode_time(db, wg_strp_iso_time(db, "12:59:00.33")));
printf("Dumping the contents of the database:\n");
wg_print_db(db);
printf("********* Demo ended ************\n");
}
static char* search(thread_data_p tdata, char* inparams[], char* invalues[],
int incount, int opcode) {
char* database=tdata->database;
char *token=NULL;
int i,j,x,itmp;
wg_int type=0;
char* fields[MAXPARAMS]; // search fields
char* values[MAXPARAMS]; // search values
char* compares[MAXPARAMS]; // search comparisons
char* types[MAXPARAMS]; // search value types
char* cids=NULL;
wg_int ids[MAXIDS]; // select these ids only
int fcount=0, vcount=0, ccount=0, tcount=0; // array el counters for above
char* sfields[MAXPARAMS]; // set / selected fields
char* svalues[MAXPARAMS]; // set field values
char* stypes[MAXPARAMS]; // set field types
int sfcount; // array el counters for above
int from=0;
unsigned long count,rcount,gcount,handlecount;
void* db=NULL; // actual database pointer
void *rec, *oldrec;
char* res;
wg_query *wgquery; // query datastructure built later
wg_query_arg wgargs[MAXPARAMS];
wg_int lock_id=0; // non-0 iff lock set
int searchtype=0; // 0: full scan, 1: record ids, 2: by fields
char errbuf[ERRBUF_LEN]; // used for building variable-content input param error strings only
// default max nr of rows shown/handled
if (opcode==COUNT_CODE) count=LONG_MAX;
else count=MAXCOUNT;
// -------check and parse cgi parameters, attach database ------------
// set params to defaults
for(i=0;i<MAXPARAMS;i++) {
fields[i]=NULL; values[i]=NULL; compares[i]=NULL; types[i]=NULL;
sfields[i]=NULL; svalues[i]=NULL; stypes[i]=NULL;
}
// set printing params to defaults
tdata->format=1; // 1: json
tdata->maxdepth=MAX_DEPTH_DEFAULT; // rec depth limit for printer
tdata->showid=0; // add record id as first extra elem: 0: no, 1: yes
tdata->strenc=2; // string special chars escaping: 0: just ", 1: urlencode, 2: json, 3: csv
// find search parameters
for(i=0;i<incount;i++) {
if (strncmp(inparams[i],"recids",MAXQUERYLEN)==0) {
cids=invalues[i];
x=0;
// set ids to defaults
for(j=0;j<MAXIDS;j++) ids[j]=0;
// split csv int list to ids int array
for(j=0;j<strlen(cids);j++) {
if (atoi(cids+j) && atoi(cids+j)>0) ids[x++]=atoi(cids+j);
if (x>=MAXIDS) break;
for(;j<strlen(cids) && cids[j]!=','; j++) {};
}
} else if (strncmp(inparams[i],"fld",MAXQUERYLEN)==0) {
res=handle_fld_param(tdata,inparams[i],invalues[i],
&sfields[sfcount],&svalues[sfcount],&stypes[sfcount],sfcount,errbuf);
if (res!=NULL) return res; // return error string
sfcount++;
} else if (strncmp(inparams[i],"field",MAXQUERYLEN)==0) {
fields[fcount++]=invalues[i];
} else if (strncmp(inparams[i],"value",MAXQUERYLEN)==0) {
values[vcount++]=invalues[i];
} else if (strncmp(inparams[i],"compare",MAXQUERYLEN)==0) {
compares[ccount++]=invalues[i];
} else if (strncmp(inparams[i],"type",MAXQUERYLEN)==0) {
types[tcount++]=invalues[i];
} else if (strncmp(inparams[i],"from",MAXQUERYLEN)==0) {
from=atoi(invalues[i]);
} else if (strncmp(inparams[i],"count",MAXQUERYLEN)==0) {
count=atoi(invalues[i]);
} else {
// handle generic parameters for all queries: at end of param check
res=handle_generic_param(tdata,inparams[i],invalues[i],&token,errbuf);
if (res!=NULL) return res; // return error string
}
}
// authorization
if (opcode==DELETE_CODE || opcode==UPDATE_CODE) {
if (!authorize(WRITE_LEVEL,tdata,database,token))
return errhalt(NOT_AUTHORIZED_ERR,tdata);
} else {
if (!authorize(READ_LEVEL,tdata,database,token))
return errhalt(NOT_AUTHORIZED_ERR,tdata);
}
// all parameters and values were understood
if (tdata->format==0) {
// csv
tdata->maxdepth=0; // record structure not printed for csv
tdata->strenc=3; // only " replaced with ""
}
// check search parameters
if (cids!=NULL) {
// query by record ids
if (fcount) return errhalt(RECIDS_COMBINED_ERR,tdata);
searchtype=1;
} else if (!fcount) {
// no search fields given
if (vcount || ccount || tcount) return errhalt(NO_FIELD_ERR,tdata);
else searchtype=0; // scan everything
} else {
// search by fields
searchtype=2;
}
// attach to database
db=op_attach_database(tdata,database,READ_LEVEL);
if (!db) return errhalt(DB_ATTACH_ERR,tdata);
// database attached OK
// create output string buffer (may be reallocated later)
tdata->buf=str_new(INITIAL_MALLOC);
if (tdata->buf==NULL) return errhalt(MALLOC_ERR,tdata);
tdata->bufsize=INITIAL_MALLOC;
tdata->bufptr=tdata->buf;
// check printing depth
if (tdata->maxdepth>MAX_DEPTH_HARD) tdata->maxdepth=MAX_DEPTH_HARD;
// initial print
if(!op_print_data_start(tdata,opcode==SEARCH_CODE))
return err_clear_detach_halt(MALLOC_ERR,tdata);
// zero counters
rcount=0;
gcount=0;
handlecount=0; // actual nr of records handled
// get lock
if (tdata->realthread && tdata->common->shutdown) return NULL; // for multithreading only
lock_id = wg_start_read(db); // get read lock
tdata->lock_id=lock_id;
tdata->lock_type=READ_LOCK_TYPE;
if (!lock_id) return err_clear_detach_halt(LOCK_ERR,tdata);
// handle one of the cases
if (searchtype==0) {
// ------- full scan case ---
rec=wg_get_first_record(db);
while (rec!=NULL) {
if (rcount>=from) {
gcount++;
if (gcount>count) break;
if (opcode==COUNT_CODE) {
handlecount++;
} else if (opcode==SEARCH_CODE) {
itmp=op_print_record(tdata,rec,gcount);
if (!itmp) return err_clear_detach_halt(MALLOC_ERR,tdata);
} else if (opcode==UPDATE_CODE) {
itmp=op_update_record(tdata,db,rec,0,0);
if (!itmp) handlecount++;
}
}
oldrec=rec;
rec=wg_get_next_record(db,rec);
if (opcode==DELETE_CODE) {
x=wg_get_record_len(db,oldrec);
if (x>0) {
itmp=op_delete_record(tdata,oldrec);
if (!itmp) handlecount++;
//else err_clear_detach_halt(DELETE_ERR,tdata);
}
}
rcount++;
}
} else if (searchtype==1) {
// ------------ search by record ids: ------------
for(j=0; ids[j]!=0 && j<MAXIDS; j++) {
x=wg_get_encoded_type(db,ids[j]);
if (x!=WG_RECORDTYPE) continue;
rec=wg_decode_record(db,ids[j]);
if (rec==NULL) continue;
x=wg_get_record_len(db,rec);
if (x<=0) continue;
gcount++;
if (gcount>count) break;
if (opcode==COUNT_CODE) handlecount++;
else if (opcode==SEARCH_CODE) {
itmp=op_print_record(tdata,rec,gcount);
if (!itmp) return err_clear_detach_halt(MALLOC_ERR,tdata);
} else if (opcode==UPDATE_CODE) {
itmp=op_update_record(tdata,db,rec,0,0);
if (!itmp) handlecount++;
} else if (opcode==DELETE_CODE) {
// test that db is not null, otherwise we may corrupt the database
oldrec=wg_get_first_record(db);
if (oldrec!=NULL) {
//wg_int objecthead=dbfetch((void*)db,(void*)rec);
//printf("isfreeobject %d\n",isfreeobject((int)objecthead));
wg_print_record(db,rec);
itmp=op_delete_record(tdata,rec);
printf("deletion result %d\n",itmp);
if (!itmp) handlecount++;
//else return err_clear_detach_halt(DELETE_ERR,tdata);
}
}
}
} else if (searchtype==2) {
// ------------by field search case: ---------
// create a query list datastructure
for(i=0;i<fcount;i++) {
// field num
if (!isint(fields[i])) return err_clear_detach_halt(NO_FIELD_ERR,tdata);
itmp=atoi(fields[i]);
if(itmp<0) return err_clear_detach_halt(NO_FIELD_ERR,tdata);
// column to compare
wgargs[i].column = itmp;
// comparison op: default equal
wgargs[i].cond = encode_incomp(db,compares[i]);
if (wgargs[i].cond==BAD_WG_VALUE) return err_clear_detach_halt(COND_ERR,tdata);
// valuetype: default guess from value later
type=encode_intype(db,types[i]);
if (type==BAD_WG_VALUE) return err_clear_detach_halt(INTYPE_ERR,tdata);
// encode value to compare with
wgargs[i].value = encode_invalue(db,values[i],type);
if (wgargs[i].value==WG_ILLEGAL) return err_clear_detach_halt(INTYPE_ERR,tdata);
}
// make the query structure
wgquery = wg_make_query(db, NULL, 0, wgargs, i);
if (!wgquery) return err_clear_detach_halt(QUERY_ERR,tdata);
// actually perform the query
if (tdata->maxdepth>MAX_DEPTH_HARD) tdata->maxdepth=MAX_DEPTH_HARD;
while((rec = wg_fetch(db, wgquery))) {
if (rcount>=from) {
gcount++;
if (opcode==COUNT_CODE) handlecount++;
else if (opcode==SEARCH_CODE) {
itmp=op_print_record(tdata,rec,gcount);
if (!itmp) return err_clear_detach_halt(MALLOC_ERR,tdata);
} else if (opcode==UPDATE_CODE) {
itmp=op_update_record(tdata,db,rec,0,0);
if (!itmp) handlecount++;
} else if (opcode==DELETE_CODE) {
itmp=op_delete_record(tdata,rec);
if (!itmp) handlecount++;
//else return err_clear_detach_halt(DELETE_ERR,tdata);
}
}
rcount++;
if (gcount>=count) break;
}
// free query datastructure,
for(i=0;i<fcount;i++) wg_free_query_param(db, wgargs[i].value);
wg_free_query(db,wgquery);
}
// ----- cases handled ------
// print a single number for count and delete
if (opcode==COUNT_CODE || opcode==DELETE_CODE) {
if(!str_guarantee_space(tdata,MIN_STRLEN))
return err_clear_detach_halt(MALLOC_ERR,tdata);
itmp=snprintf(tdata->bufptr,MIN_STRLEN,"%lu",handlecount);
tdata->bufptr+=itmp;
}
// release locks and detach
if (!wg_end_read(db, lock_id)) { // release read lock
return err_clear_detach_halt(LOCK_RELEASE_ERR,tdata);
}
tdata->lock_id=0;
op_detach_database(tdata,db);
if(!op_print_data_end(tdata,opcode==SEARCH_CODE))
return err_clear_detach_halt(MALLOC_ERR,tdata);
return tdata->buf;
}