/[pgestraier]/trunk/pgest.c
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Revision 12 - (hide annotations)
Wed May 25 23:38:37 2005 UTC (18 years, 11 months ago) by dpavlin
File MIME type: text/plain
File size: 9766 byte(s)
added NULL handling for optional arguments

1 dpavlin 1 /*
2     * integrate Hyper Estraier into PostgreSQL
3     *
4     * Dobrica Pavlinusic <dpavlin@rot13.org> 2005-05-19
5     *
6     * TODO:
7     * - all
8     *
9     * NOTES:
10     * - clear structures with memset to support hash indexes (who whould like
11     * to create hash index on table returned from function?)
12     * - number of returned rows is set by PostgreSQL evaluator, see:
13     * http://archives.postgresql.org/pgsql-hackers/2005-02/msg00546.php
14     *
15     * Based on:
16     * - C example from PostgreSQL documentation (BSD licence)
17     * - example002.c from Hyper Estraier (GPL)
18     * - _textin/_textout from pgcurl.c (LGPL)
19     *
20     * This code is licenced under GPL
21     */
22    
23     #include "postgres.h"
24     #include "fmgr.h"
25     #include "funcapi.h"
26     #include "utils/builtins.h"
27     #include "utils/array.h"
28     #include "miscadmin.h"
29     #include <estraier.h>
30     #include <cabin.h>
31    
32     #define _textin(str) DirectFunctionCall1(textin, CStringGetDatum(str))
33     #define _textout(str) DatumGetPointer(DirectFunctionCall1(textout, PointerGetDatum(str)))
34     #define GET_STR(textp) DatumGetCString(DirectFunctionCall1(textout, PointerGetDatum(textp)))
35     #define GET_TEXT(cstrp) DatumGetTextP(DirectFunctionCall1(textin, CStringGetDatum(cstrp)))
36    
37 dpavlin 5 /* prototype */
38     char *attr2text(ESTDOC *doc, char *attr);
39 dpavlin 1
40     ESTDB *db;
41     ESTCOND *cond;
42     ESTDOC *doc;
43     const CBLIST *texts;
44     int ecode, *est_result, resnum, i, j;
45 dpavlin 3 int limit = 0;
46     int offset = 0;
47 dpavlin 1
48     /* define PostgreSQL v1 function */
49     PG_FUNCTION_INFO_V1(pgest);
50     Datum pgest(PG_FUNCTION_ARGS) {
51    
52     FuncCallContext *funcctx;
53     int call_cntr;
54     int max_calls;
55     TupleDesc tupdesc;
56     TupleTableSlot *slot;
57     AttInMetadata *attinmeta;
58     char *index_path;
59     char *query;
60 dpavlin 5 char *attr;
61 dpavlin 1
62     /* stuff done only on the first call of the function */
63     if (SRF_IS_FIRSTCALL()) {
64     MemoryContext oldcontext;
65    
66     /* create a function context for cross-call persistence */
67     funcctx = SRF_FIRSTCALL_INIT();
68    
69     /* switch to memory context appropriate for multiple function calls */
70     oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
71 dpavlin 12 /* take arguments from function */
72 dpavlin 1
73 dpavlin 12 /* index path */
74     if (PG_ARGISNULL(0)) {
75     elog(ERROR, "index path can't be null");
76     SRF_RETURN_DONE(funcctx);
77     }
78     index_path = _textout(PG_GETARG_TEXT_P(0));
79    
80     /* query string */
81     if (PG_ARGISNULL(0)) {
82     query = "";
83     } else {
84     query = _textout(PG_GETARG_TEXT_P(1));
85     }
86    
87     /* atribute filter */
88     if (PG_ARGISNULL(2)) {
89     attr = "";
90     } else {
91     attr = _textout(PG_GETARG_TEXT_P(2));
92     }
93    
94     /* limit */
95     if (! PG_ARGISNULL(3)) limit = PG_GETARG_INT32(3);
96    
97     /* offset */
98     if (! PG_ARGISNULL(4)) offset = PG_GETARG_INT32(4);
99    
100    
101 dpavlin 1 /* open the database */
102     elog(DEBUG1, "pgest: est_db_open(%s)", index_path);
103    
104     if(!(db = est_db_open(index_path, ESTDBREADER, &ecode))){
105     elog(ERROR, "est_db_open: can't open %s [%d]: %s", index_path, ecode, est_err_msg(ecode));
106     SRF_RETURN_DONE(funcctx);
107     }
108    
109 dpavlin 12 elog(INFO, "pgest: query[%s] attr[%s] limit %d offset %d", query, (PG_ARGISNULL(2) ? "NULL" : attr), limit, offset);
110 dpavlin 1
111     /* create a search condition object */
112     if (!(cond = est_cond_new())) {
113     elog(INFO, "pgest: est_cond_new failed");
114     SRF_RETURN_DONE(funcctx);
115     }
116    
117     /* set the search phrase to the search condition object */
118 dpavlin 12 if (! PG_ARGISNULL(1) && strlen(query) > 0)
119 dpavlin 9 est_cond_set_phrase(cond, query);
120 dpavlin 1
121 dpavlin 5 /* minimum valid attribute length is 10: @a STREQ a */
122 dpavlin 12 if (! PG_ARGISNULL(2) && strlen(attr) >= 10) {
123 dpavlin 5 elog(INFO,"est_cond_add_attr(%s)", attr);
124     est_cond_add_attr(cond, attr);
125     }
126    
127 dpavlin 1 /* get the result of search */
128     est_result = est_db_search(db, cond, &resnum, NULL);
129    
130     /* total number of tuples to be returned */
131 dpavlin 5 if (limit && limit < resnum) {
132     funcctx->max_calls = limit - offset;
133     } else {
134     funcctx->max_calls = resnum - offset;
135     }
136 dpavlin 1
137     /* check if results exists */
138     if ( 0 == funcctx->max_calls )
139     elog(INFO, "pgest: no results for: %s", query );
140    
141 dpavlin 5 elog(DEBUG1, "pgest: found %d hits for %s", resnum, query);
142 dpavlin 1
143     /* Build a tuple description for a __pgest tuple */
144     tupdesc = RelationNameGetTupleDesc("__pgest");
145    
146     /* allocate a slot for a tuple with this tupdesc */
147     slot = TupleDescGetSlot(tupdesc);
148    
149     /* assign slot to function context */
150     funcctx->slot = slot;
151    
152     /*
153     * generate attribute metadata needed later to produce tuples from raw
154     * C strings
155     */
156     attinmeta = TupleDescGetAttInMetadata(tupdesc);
157     funcctx->attinmeta = attinmeta;
158    
159     MemoryContextSwitchTo(oldcontext);
160    
161 dpavlin 2 elog(DEBUG1, "SRF_IS_FIRSTCALL done");
162 dpavlin 1 }
163    
164     /* stuff done on every call of the function */
165     funcctx = SRF_PERCALL_SETUP();
166    
167     call_cntr = funcctx->call_cntr;
168     max_calls = funcctx->max_calls;
169     slot = funcctx->slot;
170     attinmeta = funcctx->attinmeta;
171 dpavlin 3
172     if (limit && call_cntr > limit - 1) {
173     elog(INFO, "call_cntr: %d limit: %d", call_cntr, limit);
174     SRF_RETURN_DONE(funcctx);
175     }
176    
177 dpavlin 1 if (call_cntr < max_calls) {
178     char **values;
179     HeapTuple tuple;
180     Datum result;
181    
182 dpavlin 2 elog(DEBUG1, "pgest: loop count %d", call_cntr);
183 dpavlin 1
184     if (! est_result) {
185     elog(ERROR, "pgest: no estraier results");
186     SRF_RETURN_DONE(funcctx);
187     }
188    
189     /*
190     * Prepare a values array for storage in our slot.
191     * This should be an array of C strings which will
192     * be processed later by the type input functions.
193     */
194    
195 dpavlin 3 if (doc = est_db_get_doc(db, est_result[call_cntr + offset], 0)) {
196 dpavlin 1
197 dpavlin 2 elog(DEBUG1, "URI: %s\n Title: %s\n",
198 dpavlin 1 est_doc_attr(doc, "@uri"),
199     est_doc_attr(doc, "@title")
200     );
201    
202     values = (char **) palloc(4 * sizeof(char *));
203    
204     // values[0] = (char *) palloc(strlen(_estval) * sizeof(char));
205    
206 dpavlin 5 values[0] = (char *) attr2text(doc,"@id");
207     values[1] = (char *) attr2text(doc,"@uri");
208     values[2] = (char *) attr2text(doc,"@title");
209     values[3] = (char *) attr2text(doc,"@type");
210 dpavlin 1
211     /* destloy the document object */
212     elog(DEBUG2, "est_doc_delete");
213     est_doc_delete(doc);
214     } else {
215     elog(INFO, "no result from estraier");
216 dpavlin 7 values[0] = DatumGetCString( "" );
217     values[1] = DatumGetCString( "" );
218     values[2] = DatumGetCString( "" );
219     values[3] = DatumGetCString( "" );
220 dpavlin 1 }
221    
222    
223     elog(DEBUG2, "build tuple");
224     /* build a tuple */
225     tuple = BuildTupleFromCStrings(attinmeta, values);
226    
227     elog(DEBUG2, "make tuple into datum");
228     /* make the tuple into a datum */
229     result = TupleGetDatum(slot, tuple);
230    
231     elog(DEBUG2, "cleanup");
232     /* clean up ? */
233     /*
234     pfree(values[0]);
235     pfree(values[1]);
236     pfree(values[2]);
237     pfree(values[3]);
238     pfree(values);
239     */
240    
241     elog(DEBUG2, "cleanup over");
242    
243     SRF_RETURN_NEXT(funcctx, result);
244     } else {
245 dpavlin 2 elog(DEBUG1, "loop over");
246 dpavlin 1
247     if(!est_db_close(db, &ecode)){
248     elog(INFO, "est_db_close error: %s", est_err_msg(ecode));
249     }
250    
251     /* do when there is no more left */
252     SRF_RETURN_DONE(funcctx);
253     }
254     }
255    
256     /* work in progress */
257     PG_FUNCTION_INFO_V1(pgest2);
258     Datum pgest2(PG_FUNCTION_ARGS)
259     {
260     int nrows = 3;
261     int16 typlen;
262     bool typbyval;
263     char typalign;
264     ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
265     AttInMetadata *attinmeta;
266     TupleDesc tupdesc;
267     Tuplestorestate *tupstore = NULL;
268     HeapTuple tuple;
269     MemoryContext per_query_ctx;
270     MemoryContext oldcontext;
271     Datum dvalue;
272     char **values;
273     int ncols;
274     int i, j;
275    
276     /* check to see if caller supports us returning a tuplestore */
277     if (!rsinfo || !(rsinfo->allowedModes & SFRM_Materialize))
278     ereport(ERROR,
279     (errcode(ERRCODE_SYNTAX_ERROR),
280     errmsg("materialize mode required, but it is not " \
281     "allowed in this context")));
282    
283     /* get the requested return tuple description */
284     tupdesc = rsinfo->expectedDesc;
285     ncols = tupdesc->natts;
286    
287     /*
288     * The requested tuple description better match up with the array
289     * we were given.
290     */
291     /* OK, use it */
292     attinmeta = TupleDescGetAttInMetadata(tupdesc);
293    
294     /* Now go to work */
295     rsinfo->returnMode = SFRM_Materialize;
296    
297     per_query_ctx = fcinfo->flinfo->fn_mcxt;
298     oldcontext = MemoryContextSwitchTo(per_query_ctx);
299    
300     /* initialize our tuplestore */
301     tupstore = tuplestore_begin_heap(true, false, SortMem);
302    
303     values = (char **) palloc(ncols * sizeof(char *));
304    
305     for (i = 0; i < nrows; i++)
306     {
307     for (j = 0; j < ncols; j++)
308     {
309     values[j] = DatumGetCString( "foo" );
310     }
311     /* construct the tuple */
312     tuple = BuildTupleFromCStrings(attinmeta, values);
313    
314     /* now store it */
315     tuplestore_puttuple(tupstore, tuple);
316     }
317    
318     tuplestore_donestoring(tupstore);
319     rsinfo->setResult = tupstore;
320    
321     /*
322     * SFRM_Materialize mode expects us to return a NULL Datum. The actual
323     * tuples are in our tuplestore and passed back through
324     * rsinfo->setResult. rsinfo->setDesc is set to the tuple description
325     * that we actually used to build our tuples with, so the caller can
326     * verify we did what it was expecting.
327     */
328     rsinfo->setDesc = tupdesc;
329     MemoryContextSwitchTo(oldcontext);
330    
331     return (Datum) 0;
332     }
333    
334    
335     /* make text var from attr */
336     char *attr2text(ESTDOC *doc, char *attr) {
337     char *val;
338     const char *attrval;
339     int len;
340 dpavlin 4 int attrlen;
341 dpavlin 1
342 dpavlin 2 elog(DEBUG1, "doc: %08x, attr: %s", doc, attr);
343 dpavlin 1
344 dpavlin 4 if ( (attrval = est_doc_attr(doc, attr)) && (attrlen = strlen(attrval)) ) {
345     val = (char *) palloc(attrlen * sizeof(char));
346 dpavlin 1 } else {
347     return (Datum) NULL;
348     }
349    
350     len = strlen(attrval);
351 dpavlin 2 elog(DEBUG1, "attr2text(%s) = '%s' %d bytes", attr, attrval, len);
352 dpavlin 1
353     len++;
354     len *= sizeof(char);
355    
356     elog(DEBUG2, "palloc(%d)", len);
357    
358     val = palloc(len);
359    
360     memset(val, 0, len);
361     strncpy(val, attrval, len);
362    
363     elog(DEBUG2, "val=%s", val);
364    
365     return val;
366     }
367    
368     /* make integer variable from property */
369     /*
370     char *prop2int(SW_RESULT sw_res, char *propname) {
371     char *val;
372     unsigned long prop;
373     int len;
374    
375     elog(DEBUG2, "prop2int(%s)", propname);
376    
377     prop = estResultPropertyULong( sw_res, propname );
378     if (error_or_abort( est_handle )) return NULL;
379    
380     elog(DEBUG1, "prop2int(%s) = %lu", propname, prop);
381    
382     len = 128 * sizeof(char);
383     elog(DEBUG2, "palloc(%d)", len);
384    
385     val = palloc(len);
386     memset(val, 0, len);
387    
388     snprintf(val, len, "%lu", prop);
389    
390     elog(DEBUG2, "val=%s", val);
391    
392     return val;
393     }
394     */

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