pgswish/trunk/pgswish.c

/*
 * integrate swish-e into PostgreSQL
 *
 * Dobrica Pavlinusic <dpavlin@rot13.org> 2005-02-18
 *
 * TODO:
 * - check null input using PG_ARGISNULL before using PG_GETARG_xxxx
 * - support composite type arguments
 *
 * NOTES:
 * - clear structures with memset to support hash indexes (who whould like
 *   to create hash index on table returned from function?)
 * - number of returned rows is set by PostgreSQL evaluator, see:
 *   http://archives.postgresql.org/pgsql-hackers/2005-02/msg00546.php
 *
 * Based on:
 * - C example from PostgreSQL documentation (BSD licence)
 * - swish-e example src/libtest.c (GPL)
 * - _textin/_textout from pgcurl.c (LGPL)
 *
 * This code is licenced under GPL
 */

#include "postgres.h"
#include "fmgr.h"
#include "funcapi.h"
#include "utils/builtins.h"
#include <swish-e.h>

#define _textin(str) DirectFunctionCall1(textin, CStringGetDatum(str))
#define _textout(str) DatumGetPointer(DirectFunctionCall1(textout, PointerGetDatum(str)))


SW_HANDLE   swish_handle = NULL;/* Database handle */
SW_SEARCH   search = NULL;      /* search handle -- holds search parameters */
SW_RESULTS  results = NULL;     /* results handle -- holds list of results */

/* define PostgreSQL v1 function */
PG_FUNCTION_INFO_V1(pgswish);
Datum pgswish(PG_FUNCTION_ARGS) {

        FuncCallContext *funcctx;
        int             call_cntr;
        int             max_calls;
        TupleDesc       tupdesc;
        TupleTableSlot  *slot;
        AttInMetadata   *attinmeta;
        SW_HANDLE       swish_handle = NULL;    /* Database handle */
        SW_SEARCH       search = NULL;          /* search handle -- holds search parameters */
        SW_RESULTS      results = NULL;         /* results handle -- holds list of results */
        char            *index_path;
        char            *query;

        /* stuff done only on the first call of the function */
        if (SRF_IS_FIRSTCALL()) {
                MemoryContext   oldcontext;

                /* take arguments from function */
                //index_path = _textout(PG_GETARG_TEXT_P(0));
                index_path = _textout(PG_GETARG_TEXT_P(0));
                query = _textout(PG_GETARG_TEXT_P(1));

                /* create a function context for cross-call persistence */
                funcctx = SRF_FIRSTCALL_INIT();

                /* switch to memory context appropriate for multiple function calls */
                oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);

                
                /* Send any errors or warnings to stderr (default is stdout) */
                SwishErrorsToStderr();

                elog(INFO, "pgswish: SwishInit(%s)", index_path);
                
                swish_handle = SwishInit( index_path );

                if (! swish_handle) {
                        elog(ERROR, "pgswish: can't open %s", index_path);
                        SRF_RETURN_DONE(funcctx);
                }
                
                if ( SwishError( swish_handle ) ) error_or_abort( swish_handle );
                /* set ranking scheme. default is 0 */
                SwishRankScheme( swish_handle, 0 );

                /* Check for errors after every call */
                if ( SwishError( swish_handle ) )
                        error_or_abort( swish_handle );  /* print an error or abort -- see below */

                elog(INFO, "pgswish: SwishQuery(%s)", query);
                /* Here's a short-cut to searching that creates a search object and searches at the same time */
                results = SwishQuery( swish_handle, query);
                if ( SwishError( swish_handle ) ) error_or_abort( swish_handle );

                /* total number of tuples to be returned */
                funcctx->max_calls = SwishHits( results );

                /* check if results exists */
                if ( 0 == funcctx->max_calls )
                        elog(INFO, "no results for: %s", query );

                elog(INFO, "pgswish: SwishHits = %d", funcctx->max_calls);

                /* Build a tuple description for a __pgswish tuple */
                tupdesc = RelationNameGetTupleDesc("__pgswish");

                /* allocate a slot for a tuple with this tupdesc */
                slot = TupleDescGetSlot(tupdesc);

                /* assign slot to function context */
                funcctx->slot = slot;

                /*
                 * generate attribute metadata needed later to produce tuples from raw
                 * C strings
                 */
                attinmeta = TupleDescGetAttInMetadata(tupdesc);
                funcctx->attinmeta = attinmeta;

                MemoryContextSwitchTo(oldcontext);
        }

        /* stuff done on every call of the function */
        funcctx = SRF_PERCALL_SETUP();

        call_cntr = funcctx->call_cntr;
        max_calls = funcctx->max_calls;
        slot = funcctx->slot;
        attinmeta = funcctx->attinmeta;
 
        if (call_cntr < max_calls) {
                char            **values;
                HeapTuple       tuple;
                Datum           result;

if (0) {
                /*
                 * Prepare a values array for storage in our slot.
                 * This should be an array of C strings which will
                 * be processed later by the type input functions.
                 */
                values = (char **) palloc(5 * sizeof(char *));
                values[0] = _textout( SwishResultPropertyULong ( result, "swishrank" ) );
                values[1] = _textout( SwishResultPropertyStr   ( result, "swishdocpath" ) );
                values[2] = _textout( SwishResultPropertyStr   ( result, "swishtitle" ) );
                values[3] = _textout( SwishResultPropertyStr   ( result, "swishdocsize" ) );
                values[4] = _textout( SwishResultPropertyStr   ( result, "swishdbfile" ) );

                /* build a tuple */
                tuple = BuildTupleFromCStrings(attinmeta, values);

                /* make the tuple into a datum */
                result = TupleGetDatum(slot, tuple);

}
                /* clean up (this is not really necessary) */

                SRF_RETURN_NEXT(funcctx, result);
        } else {
                /* free swish object and close */
                Free_Search_Object( search );
                SwishClose( swish_handle );

                /* do when there is no more left */
                SRF_RETURN_DONE(funcctx);
        }
}

/*
 * elog errors
 *
 */

static void error_or_abort( SW_HANDLE swish_handle ) {
        if ( !SwishError( swish_handle ) )
                return;

        /* print a message */
        elog(ERROR, 
                "pgswish error: Number [%d], Type [%s],  Optional Message: [%s]\n",
                        SwishError( swish_handle ),
                        SwishErrorString( swish_handle ),
                        SwishLastErrorMsg( swish_handle )
        );
        if ( search ) Free_Search_Object( search );
        SwishClose( swish_handle );

        /* do when there is no more left */
}

1	dpavlin	8	/*
2			* integrate swish-e into PostgreSQL
3			*
4			* Dobrica Pavlinusic <dpavlin@rot13.org> 2005-02-18
5			*
6			* TODO:
7			* - check null input using PG_ARGISNULL before using PG_GETARG_xxxx
8			* - support composite type arguments
9			*
10			* NOTES:
11			* - clear structures with memset to support hash indexes (who whould like
12			* to create hash index on table returned from function?)
13	dpavlin	10	* - number of returned rows is set by PostgreSQL evaluator, see:
14			* http://archives.postgresql.org/pgsql-hackers/2005-02/msg00546.php
15	dpavlin	8	*
16	dpavlin	9	* Based on:
17			* - C example from PostgreSQL documentation (BSD licence)
18			* - swish-e example src/libtest.c (GPL)
19			* - _textin/_textout from pgcurl.c (LGPL)
20			*
21			* This code is licenced under GPL
22	dpavlin	8	*/
23
24			#include "postgres.h"
25			#include "fmgr.h"
26			#include "funcapi.h"
27	dpavlin	9	#include "utils/builtins.h"
28	dpavlin	8	#include <swish-e.h>
29
30	dpavlin	9	#define _textin(str) DirectFunctionCall1(textin, CStringGetDatum(str))
31			#define _textout(str) DatumGetPointer(DirectFunctionCall1(textout, PointerGetDatum(str)))
32	dpavlin	8
33	dpavlin	9
34	dpavlin	8	SW_HANDLE swish_handle = NULL;/* Database handle */
35			SW_SEARCH search = NULL; /* search handle -- holds search parameters */
36			SW_RESULTS results = NULL; /* results handle -- holds list of results */
37
38			/* define PostgreSQL v1 function */
39			PG_FUNCTION_INFO_V1(pgswish);
40			Datum pgswish(PG_FUNCTION_ARGS) {
41
42			FuncCallContext *funcctx;
43			int call_cntr;
44			int max_calls;
45			TupleDesc tupdesc;
46			TupleTableSlot *slot;
47			AttInMetadata *attinmeta;
48			SW_HANDLE swish_handle = NULL; /* Database handle */
49			SW_SEARCH search = NULL; /* search handle -- holds search parameters */
50			SW_RESULTS results = NULL; /* results handle -- holds list of results */
51	dpavlin	9	char *index_path;
52			char *query;
53	dpavlin	8
54			/* stuff done only on the first call of the function */
55			if (SRF_IS_FIRSTCALL()) {
56			MemoryContext oldcontext;
57
58	dpavlin	9	/* take arguments from function */
59			//index_path = _textout(PG_GETARG_TEXT_P(0));
60			index_path = _textout(PG_GETARG_TEXT_P(0));
61			query = _textout(PG_GETARG_TEXT_P(1));
62
63	dpavlin	8	/* create a function context for cross-call persistence */
64			funcctx = SRF_FIRSTCALL_INIT();
65
66			/* switch to memory context appropriate for multiple function calls */
67			oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
68
69	dpavlin	9
70	dpavlin	8	/* Send any errors or warnings to stderr (default is stdout) */
71			SwishErrorsToStderr();
72
73	dpavlin	9	elog(INFO, "pgswish: SwishInit(%s)", index_path);
74	dpavlin	8
75	dpavlin	9	swish_handle = SwishInit( index_path );
76	dpavlin	8
77			if (! swish_handle) {
78	dpavlin	9	elog(ERROR, "pgswish: can't open %s", index_path);
79	dpavlin	8	SRF_RETURN_DONE(funcctx);
80			}
81
82			if ( SwishError( swish_handle ) ) error_or_abort( swish_handle );
83			/* set ranking scheme. default is 0 */
84	dpavlin	10	SwishRankScheme( swish_handle, 0 );
85	dpavlin	8
86			/* Check for errors after every call */
87			if ( SwishError( swish_handle ) )
88			error_or_abort( swish_handle ); /* print an error or abort -- see below */
89
90	dpavlin	9	elog(INFO, "pgswish: SwishQuery(%s)", query);
91	dpavlin	8	/* Here's a short-cut to searching that creates a search object and searches at the same time */
92	dpavlin	9	results = SwishQuery( swish_handle, query);
93	dpavlin	8	if ( SwishError( swish_handle ) ) error_or_abort( swish_handle );
94
95			/* total number of tuples to be returned */
96			funcctx->max_calls = SwishHits( results );
97
98			/* check if results exists */
99			if ( 0 == funcctx->max_calls )
100	dpavlin	9	elog(INFO, "no results for: %s", query );
101	dpavlin	8
102	dpavlin	9	elog(INFO, "pgswish: SwishHits = %d", funcctx->max_calls);
103
104	dpavlin	8	/* Build a tuple description for a __pgswish tuple */
105			tupdesc = RelationNameGetTupleDesc("__pgswish");
106
107			/* allocate a slot for a tuple with this tupdesc */
108			slot = TupleDescGetSlot(tupdesc);
109
110			/* assign slot to function context */
111			funcctx->slot = slot;
112
113			/*
114			* generate attribute metadata needed later to produce tuples from raw
115			* C strings
116			*/
117			attinmeta = TupleDescGetAttInMetadata(tupdesc);
118			funcctx->attinmeta = attinmeta;
119
120			MemoryContextSwitchTo(oldcontext);
121			}
122
123			/* stuff done on every call of the function */
124			funcctx = SRF_PERCALL_SETUP();
125
126			call_cntr = funcctx->call_cntr;
127			max_calls = funcctx->max_calls;
128			slot = funcctx->slot;
129			attinmeta = funcctx->attinmeta;
130
131			if (call_cntr < max_calls) {
132			char **values;
133			HeapTuple tuple;
134			Datum result;
135
136			if (0) {
137			/*
138			* Prepare a values array for storage in our slot.
139			* This should be an array of C strings which will
140			* be processed later by the type input functions.
141			*/
142	dpavlin	9	values = (char *) palloc(5 sizeof(char *));
143			values[0] = _textout( SwishResultPropertyULong ( result, "swishrank" ) );
144			values[1] = _textout( SwishResultPropertyStr ( result, "swishdocpath" ) );
145			values[2] = _textout( SwishResultPropertyStr ( result, "swishtitle" ) );
146			values[3] = _textout( SwishResultPropertyStr ( result, "swishdocsize" ) );
147			values[4] = _textout( SwishResultPropertyStr ( result, "swishdbfile" ) );
148	dpavlin	8
149			/* build a tuple */
150			tuple = BuildTupleFromCStrings(attinmeta, values);
151
152			/* make the tuple into a datum */
153			result = TupleGetDatum(slot, tuple);
154
155			}
156			/* clean up (this is not really necessary) */
157
158			SRF_RETURN_NEXT(funcctx, result);
159			} else {
160			/* free swish object and close */
161			Free_Search_Object( search );
162			SwishClose( swish_handle );
163
164			/* do when there is no more left */
165			SRF_RETURN_DONE(funcctx);
166			}
167			}
168
169			/*
170			* elog errors
171			*
172			*/
173
174			static void error_or_abort( SW_HANDLE swish_handle ) {
175			if ( !SwishError( swish_handle ) )
176			return;
177
178			/* print a message */
179			elog(ERROR,
180			"pgswish error: Number [%d], Type [%s], Optional Message: [%s]\n",
181			SwishError( swish_handle ),
182			SwishErrorString( swish_handle ),
183			SwishLastErrorMsg( swish_handle )
184			);
185			if ( search ) Free_Search_Object( search );
186			SwishClose( swish_handle );
187
188			/* do when there is no more left */
189			}
190