LCOV - code coverage report
Current view: top level - contrib/tcn - tcn.c (source / functions) Hit Total Coverage
Test: PostgreSQL 12beta2 Lines: 0 67 0.0 %
Date: 2019-06-18 07:06:57 Functions: 0 4 0.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * tcn.c
       4             :  *    triggered change notification support for PostgreSQL
       5             :  *
       6             :  * Portions Copyright (c) 2011-2019, PostgreSQL Global Development Group
       7             :  * Portions Copyright (c) 1994, Regents of the University of California
       8             :  *
       9             :  *
      10             :  * IDENTIFICATION
      11             :  *    contrib/tcn/tcn.c
      12             :  *
      13             :  *-------------------------------------------------------------------------
      14             :  */
      15             : 
      16             : #include "postgres.h"
      17             : 
      18             : #include "access/htup_details.h"
      19             : #include "executor/spi.h"
      20             : #include "commands/async.h"
      21             : #include "commands/trigger.h"
      22             : #include "lib/stringinfo.h"
      23             : #include "utils/rel.h"
      24             : #include "utils/syscache.h"
      25             : 
      26           0 : PG_MODULE_MAGIC;
      27             : 
      28             : /*
      29             :  * Copy from s (for source) to r (for result), wrapping with q (quote)
      30             :  * characters and doubling any quote characters found.
      31             :  */
      32             : static void
      33           0 : strcpy_quoted(StringInfo r, const char *s, const char q)
      34             : {
      35           0 :     appendStringInfoCharMacro(r, q);
      36           0 :     while (*s)
      37             :     {
      38           0 :         if (*s == q)
      39           0 :             appendStringInfoCharMacro(r, q);
      40           0 :         appendStringInfoCharMacro(r, *s);
      41           0 :         s++;
      42             :     }
      43           0 :     appendStringInfoCharMacro(r, q);
      44           0 : }
      45             : 
      46             : /*
      47             :  * triggered_change_notification
      48             :  *
      49             :  * This trigger function will send a notification of data modification with
      50             :  * primary key values.  The channel will be "tcn" unless the trigger is
      51             :  * created with a parameter, in which case that parameter will be used.
      52             :  */
      53           0 : PG_FUNCTION_INFO_V1(triggered_change_notification);
      54             : 
      55             : Datum
      56           0 : triggered_change_notification(PG_FUNCTION_ARGS)
      57             : {
      58           0 :     TriggerData *trigdata = (TriggerData *) fcinfo->context;
      59             :     Trigger    *trigger;
      60             :     int         nargs;
      61             :     HeapTuple   trigtuple;
      62             :     Relation    rel;
      63             :     TupleDesc   tupdesc;
      64             :     char       *channel;
      65             :     char        operation;
      66           0 :     StringInfo  payload = makeStringInfo();
      67             :     bool        foundPK;
      68             : 
      69             :     List       *indexoidlist;
      70             :     ListCell   *indexoidscan;
      71             : 
      72             :     /* make sure it's called as a trigger */
      73           0 :     if (!CALLED_AS_TRIGGER(fcinfo))
      74           0 :         ereport(ERROR,
      75             :                 (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
      76             :                  errmsg("triggered_change_notification: must be called as trigger")));
      77             : 
      78             :     /* and that it's called after the change */
      79           0 :     if (!TRIGGER_FIRED_AFTER(trigdata->tg_event))
      80           0 :         ereport(ERROR,
      81             :                 (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
      82             :                  errmsg("triggered_change_notification: must be called after the change")));
      83             : 
      84             :     /* and that it's called for each row */
      85           0 :     if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
      86           0 :         ereport(ERROR,
      87             :                 (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
      88             :                  errmsg("triggered_change_notification: must be called for each row")));
      89             : 
      90           0 :     if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
      91           0 :         operation = 'I';
      92           0 :     else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
      93           0 :         operation = 'U';
      94           0 :     else if (TRIGGER_FIRED_BY_DELETE(trigdata->tg_event))
      95           0 :         operation = 'D';
      96             :     else
      97             :     {
      98           0 :         elog(ERROR, "triggered_change_notification: trigger fired by unrecognized operation");
      99             :         operation = 'X';        /* silence compiler warning */
     100             :     }
     101             : 
     102           0 :     trigger = trigdata->tg_trigger;
     103           0 :     nargs = trigger->tgnargs;
     104           0 :     if (nargs > 1)
     105           0 :         ereport(ERROR,
     106             :                 (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
     107             :                  errmsg("triggered_change_notification: must not be called with more than one parameter")));
     108             : 
     109           0 :     if (nargs == 0)
     110           0 :         channel = "tcn";
     111             :     else
     112           0 :         channel = trigger->tgargs[0];
     113             : 
     114             :     /* get tuple data */
     115           0 :     trigtuple = trigdata->tg_trigtuple;
     116           0 :     rel = trigdata->tg_relation;
     117           0 :     tupdesc = rel->rd_att;
     118             : 
     119           0 :     foundPK = false;
     120             : 
     121             :     /*
     122             :      * Get the list of index OIDs for the table from the relcache, and look up
     123             :      * each one in the pg_index syscache until we find one marked primary key
     124             :      * (hopefully there isn't more than one such).
     125             :      */
     126           0 :     indexoidlist = RelationGetIndexList(rel);
     127             : 
     128           0 :     foreach(indexoidscan, indexoidlist)
     129             :     {
     130           0 :         Oid         indexoid = lfirst_oid(indexoidscan);
     131             :         HeapTuple   indexTuple;
     132             :         Form_pg_index index;
     133             : 
     134           0 :         indexTuple = SearchSysCache1(INDEXRELID, ObjectIdGetDatum(indexoid));
     135           0 :         if (!HeapTupleIsValid(indexTuple))  /* should not happen */
     136           0 :             elog(ERROR, "cache lookup failed for index %u", indexoid);
     137           0 :         index = (Form_pg_index) GETSTRUCT(indexTuple);
     138             :         /* we're only interested if it is the primary key and valid */
     139           0 :         if (index->indisprimary && index->indisvalid)
     140             :         {
     141           0 :             int         indnkeyatts = index->indnkeyatts;
     142             : 
     143           0 :             if (indnkeyatts > 0)
     144             :             {
     145             :                 int         i;
     146             : 
     147           0 :                 foundPK = true;
     148             : 
     149           0 :                 strcpy_quoted(payload, RelationGetRelationName(rel), '"');
     150           0 :                 appendStringInfoCharMacro(payload, ',');
     151           0 :                 appendStringInfoCharMacro(payload, operation);
     152             : 
     153           0 :                 for (i = 0; i < indnkeyatts; i++)
     154             :                 {
     155           0 :                     int         colno = index->indkey.values[i];
     156           0 :                     Form_pg_attribute attr = TupleDescAttr(tupdesc, colno - 1);
     157             : 
     158           0 :                     appendStringInfoCharMacro(payload, ',');
     159           0 :                     strcpy_quoted(payload, NameStr(attr->attname), '"');
     160           0 :                     appendStringInfoCharMacro(payload, '=');
     161           0 :                     strcpy_quoted(payload, SPI_getvalue(trigtuple, tupdesc, colno), '\'');
     162             :                 }
     163             : 
     164           0 :                 Async_Notify(channel, payload->data);
     165             :             }
     166           0 :             ReleaseSysCache(indexTuple);
     167           0 :             break;
     168             :         }
     169           0 :         ReleaseSysCache(indexTuple);
     170             :     }
     171             : 
     172           0 :     list_free(indexoidlist);
     173             : 
     174           0 :     if (!foundPK)
     175           0 :         ereport(ERROR,
     176             :                 (errcode(ERRCODE_E_R_I_E_TRIGGER_PROTOCOL_VIOLATED),
     177             :                  errmsg("triggered_change_notification: must be called on a table with a primary key")));
     178             : 
     179           0 :     return PointerGetDatum(NULL);   /* after trigger; value doesn't matter */
     180             : }

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