Support PL/Tcl functions that return composite types and/or sets.
authorTom Lane <[email protected]>
Sun, 6 Nov 2016 22:56:05 +0000 (17:56 -0500)
committerTom Lane <[email protected]>
Sun, 6 Nov 2016 22:56:05 +0000 (17:56 -0500)
Jim Nasby, rather heavily editorialized by me

Patch: <f2134651-14b3-efeb-f274-c69f3c084031@BlueTreble.com>

doc/src/sgml/pltcl.sgml
src/pl/tcl/expected/pltcl_queries.out
src/pl/tcl/expected/pltcl_setup.out
src/pl/tcl/pltcl.c
src/pl/tcl/sql/pltcl_queries.sql
src/pl/tcl/sql/pltcl_setup.sql

index 52fc44940c2c01a36be65d4a43edf401b3efe459..8afaf4ad36e44e1232f1d070ba62f78f63412154 100644 (file)
@@ -94,11 +94,11 @@ $$ LANGUAGE pltcl;
 
     <para>
      The body of the function is simply a piece of Tcl script.
-     When the function is called, the argument values are passed as
-     variables <literal>$1</literal> ... <literal>$<replaceable>n</replaceable></literal> to the
-     Tcl script.  The result is returned
-     from the Tcl code in the usual way, with a <literal>return</literal>
-     statement.
+     When the function is called, the argument values are passed to the
+     Tcl script as variables named <literal>1</literal>
+     ... <literal><replaceable>n</replaceable></literal>.  The result is
+     returned from the Tcl code in the usual way, with
+     a <literal>return</literal> statement.
     </para>
 
     <para>
@@ -173,17 +173,57 @@ $$ LANGUAGE pltcl;
     </para>
 
     <para>
-     There is currently no support for returning a composite-type
-     result value, nor for returning sets.
+     PL/Tcl functions can return composite-type results, too.  To do this,
+     the Tcl code must return a list of column name/value pairs matching
+     the expected result type.  Any column names omitted from the list
+     are returned as nulls, and an error is raised if there are unexpected
+     column names.  Here is an example:
+
+<programlisting>
+CREATE FUNCTION square_cube(in int, out squared int, out cubed int) AS $$
+    return [list squared [expr {$1 * $1}] cubed [expr {$1 * $1 * $1}]]
+$$ LANGUAGE pltcl;
+</programlisting>
     </para>
 
+    <tip>
+     <para>
+      The result list can be made from an array representation of the
+      desired tuple with the <literal>array get</> Tcl command.  For example:
+
+<programlisting>
+CREATE FUNCTION raise_pay(employee, delta int) RETURNS employee AS $$
+    set 1(salary) [expr {$1(salary) + $2}]
+    return [array get 1]
+$$ LANGUAGE pltcl;
+</programlisting>
+     </para>
+    </tip>
+
     <para>
-     <application>PL/Tcl</> does not currently have full support for
-     domain types: it treats a domain the same as the underlying scalar
-     type.  This means that constraints associated with the domain will
-     not be enforced.  This is not an issue for function arguments, but
-     it is a hazard if you declare a <application>PL/Tcl</> function
-     as returning a domain type.
+     PL/Tcl functions can return sets.  To do this, the Tcl code should
+     call <function>return_next</function> once per row to be returned,
+     passing either the appropriate value when returning a scalar type,
+     or a list of column name/value pairs when returning a composite type.
+     Here is an example returning a scalar type:
+
+<programlisting>
+CREATE FUNCTION sequence(int, int) RETURNS SETOF int AS $$
+    for {set i $1} {$i &lt; $2} {incr i} {
+        return_next $i
+    }
+$$ LANGUAGE pltcl;
+</programlisting>
+
+     and here is one returning a composite type:
+
+<programlisting>
+CREATE FUNCTION table_of_squares(int, int) RETURNS TABLE (x int, x2 int) AS $$
+    for {set i $1} {$i &lt; $2} {incr i} {
+        return_next [list x $i x2 [expr {$i * $i}]]
+    }
+$$ LANGUAGE pltcl;
+</programlisting>
     </para>
 
    </sect1>
@@ -195,10 +235,9 @@ $$ LANGUAGE pltcl;
      The argument values supplied to a PL/Tcl function's code are simply
      the input arguments converted to text form (just as if they had been
      displayed by a <command>SELECT</> statement).  Conversely, the
-     <literal>return</>
-     command will accept any string that is acceptable input format for
-     the function's declared return type.  So, within the PL/Tcl function,
-     all values are just text strings.
+     <literal>return</> and <literal>return_next</> commands will accept
+     any string that is acceptable input format for the function's declared
+     result type, or for the specified column of a composite result type.
     </para>
 
    </sect1>
index 6cb1fdbb6117ec0b567dbe7dd3710541014f4aca..3a9fef34477a574b362adbcd09ac29b1496fc9ef 100644 (file)
@@ -303,3 +303,64 @@ select tcl_lastoid('t2') > 0;
  t
 (1 row)
 
+-- test some error cases
+CREATE FUNCTION tcl_error(OUT a int, OUT b int) AS $$return {$$ LANGUAGE pltcl;
+SELECT tcl_error();
+ERROR:  missing close-brace
+CREATE FUNCTION bad_record(OUT a text, OUT b text) AS $$return [list a]$$ LANGUAGE pltcl;
+SELECT bad_record();
+ERROR:  column name/value list must have even number of elements
+CREATE FUNCTION bad_field(OUT a text, OUT b text) AS $$return [list a 1 b 2 cow 3]$$ LANGUAGE pltcl;
+SELECT bad_field();
+ERROR:  column name/value list contains nonexistent column name "cow"
+-- test compound return
+select * from tcl_test_cube_squared(5);
+ squared | cubed 
+---------+-------
+      25 |   125
+(1 row)
+
+-- test SRF
+select * from tcl_test_squared_rows(0,5);
+ x | y  
+---+----
+ 0 |  0
+ 1 |  1
+ 2 |  4
+ 3 |  9
+ 4 | 16
+(5 rows)
+
+select * from tcl_test_sequence(0,5) as a;
+ a 
+---
+ 0
+ 1
+ 2
+ 3
+ 4
+(5 rows)
+
+select 1, tcl_test_sequence(0,5);
+ ?column? | tcl_test_sequence 
+----------+-------------------
+        1 |                 0
+        1 |                 1
+        1 |                 2
+        1 |                 3
+        1 |                 4
+(5 rows)
+
+CREATE FUNCTION non_srf() RETURNS int AS $$return_next 1$$ LANGUAGE pltcl;
+select non_srf();
+ERROR:  return_next cannot be used in non-set-returning functions
+CREATE FUNCTION bad_record_srf(OUT a text, OUT b text) RETURNS SETOF record AS $$
+return_next [list a]
+$$ LANGUAGE pltcl;
+SELECT bad_record_srf();
+ERROR:  column name/value list must have even number of elements
+CREATE FUNCTION bad_field_srf(OUT a text, OUT b text) RETURNS SETOF record AS $$
+return_next [list a 1 b 2 cow 3]
+$$ LANGUAGE pltcl;
+SELECT bad_field_srf();
+ERROR:  column name/value list contains nonexistent column name "cow"
index e65e9e3ff71587156cf425c93404e557a01007be..ed99d9b49224f0bdd3d23194f4f62e6b46351258 100644 (file)
@@ -555,6 +555,19 @@ NOTICE:  tclsnitch: ddl_command_start DROP TABLE
 NOTICE:  tclsnitch: ddl_command_end DROP TABLE
 drop event trigger tcl_a_snitch;
 drop event trigger tcl_b_snitch;
+CREATE FUNCTION tcl_test_cube_squared(in int, out squared int, out cubed int) AS $$
+    return [list squared [expr {$1 * $1}] cubed [expr {$1 * $1 * $1}]]
+$$ language pltcl;
+CREATE FUNCTION tcl_test_squared_rows(int,int) RETURNS TABLE (x int, y int) AS $$
+    for {set i $1} {$i < $2} {incr i} {
+        return_next [list y [expr {$i * $i}] x $i]
+    }
+$$ language pltcl;
+CREATE FUNCTION tcl_test_sequence(int,int) RETURNS SETOF int AS $$
+    for {set i $1} {$i < $2} {incr i} {
+        return_next $i
+    }
+$$ language pltcl;
 -- test use of errorCode in error handling
 create function tcl_error_handling_test() returns text as $$
     global errorCode
index 97d1f7ef7d3746936c8e68f91ebc5b2f3f5aa60c..3d529c2e7df90da3f1cad20807fb86d72f40ec9b 100644 (file)
@@ -21,6 +21,7 @@
 #include "commands/trigger.h"
 #include "executor/spi.h"
 #include "fmgr.h"
+#include "funcapi.h"
 #include "mb/pg_wchar.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
@@ -123,6 +124,9 @@ typedef struct pltcl_interp_desc
  * problem to manage its memory when we replace a proc definition.  We do
  * not clean up pltcl_proc_descs when a pg_proc row is deleted, only when
  * it is updated, and the same policy applies to Tcl's copy as well.)
+ *
+ * Note that the data in this struct is shared across all active calls;
+ * nothing except the fn_refcount should be changed by a call instance.
  **********************************************************************/
 typedef struct pltcl_proc_desc
 {
@@ -137,6 +141,8 @@ typedef struct pltcl_proc_desc
    pltcl_interp_desc *interp_desc;     /* interpreter to use */
    FmgrInfo    result_in_func; /* input function for fn's result type */
    Oid         result_typioparam;      /* param to pass to same */
+   bool        fn_retisset;    /* true if function returns a set */
+   bool        fn_retistuple;  /* true if function returns composite */
    int         nargs;          /* number of arguments */
    /* these arrays have nargs entries: */
    FmgrInfo   *arg_out_func;   /* output fns for arg types */
@@ -188,6 +194,32 @@ typedef struct pltcl_proc_ptr
 } pltcl_proc_ptr;
 
 
+/**********************************************************************
+ * Per-call state
+ **********************************************************************/
+typedef struct pltcl_call_state
+{
+   /* Call info struct, or NULL in a trigger */
+   FunctionCallInfo fcinfo;
+
+   /* Function we're executing (NULL if not yet identified) */
+   pltcl_proc_desc *prodesc;
+
+   /*
+    * Information for SRFs and functions returning composite types.
+    * ret_tupdesc and attinmeta are set up if either fn_retistuple or
+    * fn_retisset, since even a scalar-returning SRF needs a tuplestore.
+    */
+   TupleDesc   ret_tupdesc;    /* return rowtype, if retistuple or retisset */
+   AttInMetadata *attinmeta;   /* metadata for building tuples of that type */
+
+   ReturnSetInfo *rsi;         /* passed-in ReturnSetInfo, if any */
+   Tuplestorestate *tuple_store;       /* SRFs accumulate result here */
+   MemoryContext tuple_store_cxt;      /* context and resowner for tuplestore */
+   ResourceOwner tuple_store_owner;
+} pltcl_call_state;
+
+
 /**********************************************************************
  * Global data
  **********************************************************************/
@@ -196,9 +228,8 @@ static Tcl_Interp *pltcl_hold_interp = NULL;
 static HTAB *pltcl_interp_htab = NULL;
 static HTAB *pltcl_proc_htab = NULL;
 
-/* these are saved and restored by pltcl_handler */
-static FunctionCallInfo pltcl_current_fcinfo = NULL;
-static pltcl_proc_desc *pltcl_current_prodesc = NULL;
+/* this is saved and restored by pltcl_handler */
+static pltcl_call_state *pltcl_current_call_state = NULL;
 
 /**********************************************************************
  * Lookup table for SQLSTATE condition names
@@ -225,10 +256,12 @@ static void pltcl_init_load_unknown(Tcl_Interp *interp);
 
 static Datum pltcl_handler(PG_FUNCTION_ARGS, bool pltrusted);
 
-static Datum pltcl_func_handler(PG_FUNCTION_ARGS, bool pltrusted);
-
-static HeapTuple pltcl_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted);
-static void pltcl_event_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted);
+static Datum pltcl_func_handler(PG_FUNCTION_ARGS, pltcl_call_state *call_state,
+                  bool pltrusted);
+static HeapTuple pltcl_trigger_handler(PG_FUNCTION_ARGS, pltcl_call_state *call_state,
+                     bool pltrusted);
+static void pltcl_event_trigger_handler(PG_FUNCTION_ARGS, pltcl_call_state *call_state,
+                           bool pltrusted);
 
 static void throw_tcl_error(Tcl_Interp *interp, const char *proname);
 
@@ -246,7 +279,8 @@ static int pltcl_argisnull(ClientData cdata, Tcl_Interp *interp,
                int objc, Tcl_Obj *const objv[]);
 static int pltcl_returnnull(ClientData cdata, Tcl_Interp *interp,
                 int objc, Tcl_Obj *const objv[]);
-
+static int pltcl_returnnext(ClientData cdata, Tcl_Interp *interp,
+                int objc, Tcl_Obj *const objv[]);
 static int pltcl_SPI_execute(ClientData cdata, Tcl_Interp *interp,
                  int objc, Tcl_Obj *const objv[]);
 static int pltcl_process_SPI_result(Tcl_Interp *interp,
@@ -265,6 +299,10 @@ static int pltcl_SPI_lastoid(ClientData cdata, Tcl_Interp *interp,
 static void pltcl_set_tuple_values(Tcl_Interp *interp, const char *arrayname,
                       uint64 tupno, HeapTuple tuple, TupleDesc tupdesc);
 static Tcl_Obj *pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc);
+static HeapTuple pltcl_build_tuple_result(Tcl_Interp *interp,
+                        Tcl_Obj **kvObjv, int kvObjc,
+                        pltcl_call_state *call_state);
+static void pltcl_init_tuple_store(pltcl_call_state *call_state);
 
 
 /*
@@ -432,7 +470,8 @@ pltcl_init_interp(pltcl_interp_desc *interp_desc, bool pltrusted)
                         pltcl_argisnull, NULL, NULL);
    Tcl_CreateObjCommand(interp, "return_null",
                         pltcl_returnnull, NULL, NULL);
-
+   Tcl_CreateObjCommand(interp, "return_next",
+                        pltcl_returnnext, NULL, NULL);
    Tcl_CreateObjCommand(interp, "spi_exec",
                         pltcl_SPI_execute, NULL, NULL);
    Tcl_CreateObjCommand(interp, "spi_prepare",
@@ -625,29 +664,33 @@ pltclu_call_handler(PG_FUNCTION_ARGS)
 }
 
 
+/**********************************************************************
+ * pltcl_handler()     - Handler for function and trigger calls, for
+ *                       both trusted and untrusted interpreters.
+ **********************************************************************/
 static Datum
 pltcl_handler(PG_FUNCTION_ARGS, bool pltrusted)
 {
    Datum       retval;
-   FunctionCallInfo save_fcinfo;
-   pltcl_proc_desc *save_prodesc;
-   pltcl_proc_desc *this_prodesc;
+   pltcl_call_state current_call_state;
+   pltcl_call_state *save_call_state;
 
    /*
-    * Ensure that static pointers are saved/restored properly
+    * Initialize current_call_state to nulls/zeroes; in particular, set its
+    * prodesc pointer to null.  Anything that sets it non-null should
+    * increase the prodesc's fn_refcount at the same time.  We'll decrease
+    * the refcount, and then delete the prodesc if it's no longer referenced,
+    * on the way out of this function.  This ensures that prodescs live as
+    * long as needed even if somebody replaces the originating pg_proc row
+    * while they're executing.
     */
-   save_fcinfo = pltcl_current_fcinfo;
-   save_prodesc = pltcl_current_prodesc;
+   memset(&current_call_state, 0, sizeof(current_call_state));
 
    /*
-    * Reset pltcl_current_prodesc to null.  Anything that sets it non-null
-    * should increase the prodesc's fn_refcount at the same time.  We'll
-    * decrease the refcount, and then delete the prodesc if it's no longer
-    * referenced, on the way out of this function.  This ensures that
-    * prodescs live as long as needed even if somebody replaces the
-    * originating pg_proc row while they're executing.
+    * Ensure that static pointer is saved/restored properly
     */
-   pltcl_current_prodesc = NULL;
+   save_call_state = pltcl_current_call_state;
+   pltcl_current_call_state = &current_call_state;
 
    PG_TRY();
    {
@@ -657,47 +700,46 @@ pltcl_handler(PG_FUNCTION_ARGS, bool pltrusted)
         */
        if (CALLED_AS_TRIGGER(fcinfo))
        {
-           pltcl_current_fcinfo = NULL;
-           retval = PointerGetDatum(pltcl_trigger_handler(fcinfo, pltrusted));
+           /* invoke the trigger handler */
+           retval = PointerGetDatum(pltcl_trigger_handler(fcinfo,
+                                                        &current_call_state,
+                                                          pltrusted));
        }
        else if (CALLED_AS_EVENT_TRIGGER(fcinfo))
        {
-           pltcl_current_fcinfo = NULL;
-           pltcl_event_trigger_handler(fcinfo, pltrusted);
+           /* invoke the event trigger handler */
+           pltcl_event_trigger_handler(fcinfo, &current_call_state, pltrusted);
            retval = (Datum) 0;
        }
        else
        {
-           pltcl_current_fcinfo = fcinfo;
-           retval = pltcl_func_handler(fcinfo, pltrusted);
+           /* invoke the regular function handler */
+           current_call_state.fcinfo = fcinfo;
+           retval = pltcl_func_handler(fcinfo, &current_call_state, pltrusted);
        }
    }
    PG_CATCH();
    {
-       /* Restore globals, then clean up the prodesc refcount if any */
-       this_prodesc = pltcl_current_prodesc;
-       pltcl_current_fcinfo = save_fcinfo;
-       pltcl_current_prodesc = save_prodesc;
-       if (this_prodesc != NULL)
+       /* Restore static pointer, then clean up the prodesc refcount if any */
+       pltcl_current_call_state = save_call_state;
+       if (current_call_state.prodesc != NULL)
        {
-           Assert(this_prodesc->fn_refcount > 0);
-           if (--this_prodesc->fn_refcount == 0)
-               MemoryContextDelete(this_prodesc->fn_cxt);
+           Assert(current_call_state.prodesc->fn_refcount > 0);
+           if (--current_call_state.prodesc->fn_refcount == 0)
+               MemoryContextDelete(current_call_state.prodesc->fn_cxt);
        }
        PG_RE_THROW();
    }
    PG_END_TRY();
 
-   /* Restore globals, then clean up the prodesc refcount if any */
+   /* Restore static pointer, then clean up the prodesc refcount if any */
    /* (We're being paranoid in case an error is thrown in context deletion) */
-   this_prodesc = pltcl_current_prodesc;
-   pltcl_current_fcinfo = save_fcinfo;
-   pltcl_current_prodesc = save_prodesc;
-   if (this_prodesc != NULL)
+   pltcl_current_call_state = save_call_state;
+   if (current_call_state.prodesc != NULL)
    {
-       Assert(this_prodesc->fn_refcount > 0);
-       if (--this_prodesc->fn_refcount == 0)
-           MemoryContextDelete(this_prodesc->fn_cxt);
+       Assert(current_call_state.prodesc->fn_refcount > 0);
+       if (--current_call_state.prodesc->fn_refcount == 0)
+           MemoryContextDelete(current_call_state.prodesc->fn_cxt);
    }
 
    return retval;
@@ -708,7 +750,8 @@ pltcl_handler(PG_FUNCTION_ARGS, bool pltrusted)
  * pltcl_func_handler()        - Handler for regular function calls
  **********************************************************************/
 static Datum
-pltcl_func_handler(PG_FUNCTION_ARGS, bool pltrusted)
+pltcl_func_handler(PG_FUNCTION_ARGS, pltcl_call_state *call_state,
+                  bool pltrusted)
 {
    pltcl_proc_desc *prodesc;
    Tcl_Interp *volatile interp;
@@ -725,11 +768,32 @@ pltcl_func_handler(PG_FUNCTION_ARGS, bool pltrusted)
    prodesc = compile_pltcl_function(fcinfo->flinfo->fn_oid, InvalidOid,
                                     false, pltrusted);
 
-   pltcl_current_prodesc = prodesc;
+   call_state->prodesc = prodesc;
    prodesc->fn_refcount++;
 
    interp = prodesc->interp_desc->interp;
 
+   /*
+    * If we're a SRF, check caller can handle materialize mode, and save
+    * relevant info into call_state.  We must ensure that the returned
+    * tuplestore is owned by the caller's context, even if we first create it
+    * inside a subtransaction.
+    */
+   if (prodesc->fn_retisset)
+   {
+       ReturnSetInfo *rsi = (ReturnSetInfo *) fcinfo->resultinfo;
+
+       if (!rsi || !IsA(rsi, ReturnSetInfo) ||
+           (rsi->allowedModes & SFRM_Materialize) == 0)
+           ereport(ERROR,
+                   (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+                    errmsg("set-valued function called in context that cannot accept a set")));
+
+       call_state->rsi = rsi;
+       call_state->tuple_store_cxt = rsi->econtext->ecxt_per_query_memory;
+       call_state->tuple_store_owner = CurrentResourceOwner;
+   }
+
    /************************************************************
     * Create the tcl command to call the internal
     * proc in the Tcl interpreter
@@ -838,11 +902,72 @@ pltcl_func_handler(PG_FUNCTION_ARGS, bool pltrusted)
    if (SPI_finish() != SPI_OK_FINISH)
        elog(ERROR, "SPI_finish() failed");
 
-   if (fcinfo->isnull)
+   if (prodesc->fn_retisset)
+   {
+       ReturnSetInfo *rsi = call_state->rsi;
+
+       /* We already checked this is OK */
+       rsi->returnMode = SFRM_Materialize;
+
+       /* If we produced any tuples, send back the result */
+       if (call_state->tuple_store)
+       {
+           rsi->setResult = call_state->tuple_store;
+           if (call_state->ret_tupdesc)
+           {
+               MemoryContext oldcxt;
+
+               oldcxt = MemoryContextSwitchTo(call_state->tuple_store_cxt);
+               rsi->setDesc = CreateTupleDescCopy(call_state->ret_tupdesc);
+               MemoryContextSwitchTo(oldcxt);
+           }
+       }
+       retval = (Datum) 0;
+       fcinfo->isnull = true;
+   }
+   else if (fcinfo->isnull)
+   {
        retval = InputFunctionCall(&prodesc->result_in_func,
                                   NULL,
                                   prodesc->result_typioparam,
                                   -1);
+   }
+   else if (prodesc->fn_retistuple)
+   {
+       TupleDesc   td;
+       HeapTuple   tup;
+       Tcl_Obj    *resultObj;
+       Tcl_Obj   **resultObjv;
+       int         resultObjc;
+
+       /*
+        * Set up data about result type.  XXX it's tempting to consider
+        * caching this in the prodesc, in the common case where the rowtype
+        * is determined by the function not the calling query.  But we'd have
+        * to be able to deal with ADD/DROP/ALTER COLUMN events when the
+        * result type is a named composite type, so it's not exactly trivial.
+        * Maybe worth improving someday.
+        */
+       if (get_call_result_type(fcinfo, NULL, &td) != TYPEFUNC_COMPOSITE)
+           ereport(ERROR,
+                   (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+                    errmsg("function returning record called in context "
+                           "that cannot accept type record")));
+
+       Assert(!call_state->ret_tupdesc);
+       Assert(!call_state->attinmeta);
+       call_state->ret_tupdesc = td;
+       call_state->attinmeta = TupleDescGetAttInMetadata(td);
+
+       /* Convert function result to tuple */
+       resultObj = Tcl_GetObjResult(interp);
+       if (Tcl_ListObjGetElements(interp, resultObj, &resultObjc, &resultObjv) == TCL_ERROR)
+           throw_tcl_error(interp, prodesc->user_proname);
+
+       tup = pltcl_build_tuple_result(interp, resultObjv, resultObjc,
+                                      call_state);
+       retval = HeapTupleGetDatum(tup);
+   }
    else
        retval = InputFunctionCall(&prodesc->result_in_func,
                                   utf_u2e(Tcl_GetStringResult(interp)),
@@ -857,7 +982,8 @@ pltcl_func_handler(PG_FUNCTION_ARGS, bool pltrusted)
  * pltcl_trigger_handler() - Handler for trigger calls
  **********************************************************************/
 static HeapTuple
-pltcl_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
+pltcl_trigger_handler(PG_FUNCTION_ARGS, pltcl_call_state *call_state,
+                     bool pltrusted)
 {
    pltcl_proc_desc *prodesc;
    Tcl_Interp *volatile interp;
@@ -886,7 +1012,7 @@ pltcl_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
                                     false,     /* not an event trigger */
                                     pltrusted);
 
-   pltcl_current_prodesc = prodesc;
+   call_state->prodesc = prodesc;
    prodesc->fn_refcount++;
 
    interp = prodesc->interp_desc->interp;
@@ -1169,7 +1295,8 @@ pltcl_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
  * pltcl_event_trigger_handler()   - Handler for event trigger calls
  **********************************************************************/
 static void
-pltcl_event_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
+pltcl_event_trigger_handler(PG_FUNCTION_ARGS, pltcl_call_state *call_state,
+                           bool pltrusted)
 {
    pltcl_proc_desc *prodesc;
    Tcl_Interp *volatile interp;
@@ -1185,7 +1312,7 @@ pltcl_event_trigger_handler(PG_FUNCTION_ARGS, bool pltrusted)
    prodesc = compile_pltcl_function(fcinfo->flinfo->fn_oid,
                                     InvalidOid, true, pltrusted);
 
-   pltcl_current_prodesc = prodesc;
+   call_state->prodesc = prodesc;
    prodesc->fn_refcount++;
 
    interp = prodesc->interp_desc->interp;
@@ -1389,10 +1516,11 @@ compile_pltcl_function(Oid fn_oid, Oid tgreloid,
                     procStruct->prorettype);
            typeStruct = (Form_pg_type) GETSTRUCT(typeTup);
 
-           /* Disallow pseudotype result, except VOID */
+           /* Disallow pseudotype result, except VOID and RECORD */
            if (typeStruct->typtype == TYPTYPE_PSEUDO)
            {
-               if (procStruct->prorettype == VOIDOID)
+               if (procStruct->prorettype == VOIDOID ||
+                   procStruct->prorettype == RECORDOID)
                     /* okay */ ;
                else if (procStruct->prorettype == TRIGGEROID ||
                         procStruct->prorettype == EVTTRIGGEROID)
@@ -1406,16 +1534,15 @@ compile_pltcl_function(Oid fn_oid, Oid tgreloid,
                                    format_type_be(procStruct->prorettype))));
            }
 
-           if (typeStruct->typtype == TYPTYPE_COMPOSITE)
-               ereport(ERROR,
-                       (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-                 errmsg("PL/Tcl functions cannot return composite types")));
-
            fmgr_info_cxt(typeStruct->typinput,
                          &(prodesc->result_in_func),
                          proc_cxt);
            prodesc->result_typioparam = getTypeIOParam(typeTup);
 
+           prodesc->fn_retisset = procStruct->proretset;
+           prodesc->fn_retistuple = (procStruct->prorettype == RECORDOID ||
+                                  typeStruct->typtype == TYPTYPE_COMPOSITE);
+
            ReleaseSysCache(typeTup);
        }
 
@@ -1914,7 +2041,7 @@ pltcl_argisnull(ClientData cdata, Tcl_Interp *interp,
                int objc, Tcl_Obj *const objv[])
 {
    int         argno;
-   FunctionCallInfo fcinfo = pltcl_current_fcinfo;
+   FunctionCallInfo fcinfo = pltcl_current_call_state->fcinfo;
 
    /************************************************************
     * Check call syntax
@@ -1967,7 +2094,7 @@ static int
 pltcl_returnnull(ClientData cdata, Tcl_Interp *interp,
                 int objc, Tcl_Obj *const objv[])
 {
-   FunctionCallInfo fcinfo = pltcl_current_fcinfo;
+   FunctionCallInfo fcinfo = pltcl_current_call_state->fcinfo;
 
    /************************************************************
     * Check call syntax
@@ -1998,6 +2125,95 @@ pltcl_returnnull(ClientData cdata, Tcl_Interp *interp,
 }
 
 
+/**********************************************************************
+ * pltcl_returnnext()  - Add a row to the result tuplestore in a SRF.
+ **********************************************************************/
+static int
+pltcl_returnnext(ClientData cdata, Tcl_Interp *interp,
+                int objc, Tcl_Obj *const objv[])
+{
+   pltcl_call_state *call_state = pltcl_current_call_state;
+   FunctionCallInfo fcinfo = call_state->fcinfo;
+   pltcl_proc_desc *prodesc = call_state->prodesc;
+   int         result = TCL_OK;
+   MemoryContext tmpcxt;
+   MemoryContext oldcxt;
+
+   /*
+    * Check that we're called as a set-returning function
+    */
+   if (fcinfo == NULL)
+   {
+       Tcl_SetObjResult(interp,
+            Tcl_NewStringObj("return_next cannot be used in triggers", -1));
+       return TCL_ERROR;
+   }
+
+   if (!prodesc->fn_retisset)
+   {
+       Tcl_SetObjResult(interp,
+                        Tcl_NewStringObj("return_next cannot be used in non-set-returning functions", -1));
+       return TCL_ERROR;
+   }
+
+   /*
+    * Check call syntax
+    */
+   if (objc != 2)
+   {
+       Tcl_WrongNumArgs(interp, 1, objv, "result");
+       return TCL_ERROR;
+   }
+
+   /* Set up tuple store if first output row */
+   if (call_state->tuple_store == NULL)
+       pltcl_init_tuple_store(call_state);
+
+   /* Make short-lived context to run input functions in */
+   tmpcxt = AllocSetContextCreate(CurrentMemoryContext,
+                                  "pltcl_returnnext",
+                                  ALLOCSET_SMALL_SIZES);
+   oldcxt = MemoryContextSwitchTo(tmpcxt);
+
+   if (prodesc->fn_retistuple)
+   {
+       Tcl_Obj   **rowObjv;
+       int         rowObjc;
+
+       /* result should be a list, so break it down */
+       if (Tcl_ListObjGetElements(interp, objv[1], &rowObjc, &rowObjv) == TCL_ERROR)
+           result = TCL_ERROR;
+       else
+       {
+           HeapTuple   tuple;
+
+           SPI_push();
+           tuple = pltcl_build_tuple_result(interp, rowObjv, rowObjc,
+                                            call_state);
+           tuplestore_puttuple(call_state->tuple_store, tuple);
+           SPI_pop();
+       }
+   }
+   else
+   {
+       Datum       retval;
+       bool        isNull = false;
+
+       retval = InputFunctionCall(&prodesc->result_in_func,
+                                  utf_u2e((char *) Tcl_GetString(objv[1])),
+                                  prodesc->result_typioparam,
+                                  -1);
+       tuplestore_putvalues(call_state->tuple_store, call_state->ret_tupdesc,
+                            &retval, &isNull);
+   }
+
+   MemoryContextSwitchTo(oldcxt);
+   MemoryContextDelete(tmpcxt);
+
+   return result;
+}
+
+
 /*----------
  * Support for running SPI operations inside subtransactions
  *
@@ -2164,7 +2380,7 @@ pltcl_SPI_execute(ClientData cdata, Tcl_Interp *interp,
    {
        UTF_BEGIN;
        spi_rc = SPI_execute(UTF_U2E(Tcl_GetString(objv[query_idx])),
-                            pltcl_current_prodesc->fn_readonly, count);
+                     pltcl_current_call_state->prodesc->fn_readonly, count);
        UTF_END;
 
        my_rc = pltcl_process_SPI_result(interp,
@@ -2414,7 +2630,7 @@ pltcl_SPI_prepare(ClientData cdata, Tcl_Interp *interp,
     * Insert a hashtable entry for the plan and return
     * the key to the caller
     ************************************************************/
-   query_hash = &pltcl_current_prodesc->interp_desc->query_hash;
+   query_hash = &pltcl_current_call_state->prodesc->interp_desc->query_hash;
 
    hashent = Tcl_CreateHashEntry(query_hash, qdesc->qname, &hashnew);
    Tcl_SetHashValue(hashent, (ClientData) qdesc);
@@ -2503,7 +2719,7 @@ pltcl_SPI_execute_plan(ClientData cdata, Tcl_Interp *interp,
        return TCL_ERROR;
    }
 
-   query_hash = &pltcl_current_prodesc->interp_desc->query_hash;
+   query_hash = &pltcl_current_call_state->prodesc->interp_desc->query_hash;
 
    hashent = Tcl_FindHashEntry(query_hash, Tcl_GetString(objv[i]));
    if (hashent == NULL)
@@ -2618,7 +2834,8 @@ pltcl_SPI_execute_plan(ClientData cdata, Tcl_Interp *interp,
         * Execute the plan
         ************************************************************/
        spi_rc = SPI_execute_plan(qdesc->plan, argvalues, nulls,
-                                 pltcl_current_prodesc->fn_readonly, count);
+                             pltcl_current_call_state->prodesc->fn_readonly,
+                                 count);
 
        my_rc = pltcl_process_SPI_result(interp,
                                         arrayname,
@@ -2808,3 +3025,88 @@ pltcl_build_tuple_argument(HeapTuple tuple, TupleDesc tupdesc)
 
    return retobj;
 }
+
+/**********************************************************************
+ * pltcl_build_tuple_result() - Build a tuple of function's result rowtype
+ *               from a Tcl list of column names and values
+ *
+ * Note: this function leaks memory.  Even if we made it clean up its own
+ * mess, there's no way to prevent the datatype input functions it calls
+ * from leaking.  Run it in a short-lived context, unless we're about to
+ * exit the procedure anyway.
+ *
+ * Also, caller is responsible for doing SPI_push/SPI_pop if calling from
+ * inside SPI environment.
+ **********************************************************************/
+static HeapTuple
+pltcl_build_tuple_result(Tcl_Interp *interp, Tcl_Obj **kvObjv, int kvObjc,
+                        pltcl_call_state *call_state)
+{
+   char      **values;
+   int         i;
+
+   if (kvObjc % 2 != 0)
+       ereport(ERROR,
+               (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+       errmsg("column name/value list must have even number of elements")));
+
+   values = (char **) palloc0(call_state->ret_tupdesc->natts * sizeof(char *));
+
+   for (i = 0; i < kvObjc; i += 2)
+   {
+       char       *fieldName = utf_e2u(Tcl_GetString(kvObjv[i]));
+       int         attn = SPI_fnumber(call_state->ret_tupdesc, fieldName);
+
+       if (attn <= 0 || call_state->ret_tupdesc->attrs[attn - 1]->attisdropped)
+           ereport(ERROR,
+                   (errcode(ERRCODE_UNDEFINED_COLUMN),
+                    errmsg("column name/value list contains nonexistent column name \"%s\"",
+                           fieldName)));
+
+       values[attn - 1] = utf_e2u(Tcl_GetString(kvObjv[i + 1]));
+   }
+
+   return BuildTupleFromCStrings(call_state->attinmeta, values);
+}
+
+/**********************************************************************
+ * pltcl_init_tuple_store() - Initialize the result tuplestore for a SRF
+ **********************************************************************/
+static void
+pltcl_init_tuple_store(pltcl_call_state *call_state)
+{
+   ReturnSetInfo *rsi = call_state->rsi;
+   MemoryContext oldcxt;
+   ResourceOwner oldowner;
+
+   /* Should be in a SRF */
+   Assert(rsi);
+   /* Should be first time through */
+   Assert(!call_state->tuple_store);
+   Assert(!call_state->attinmeta);
+
+   /* We expect caller to provide an appropriate result tupdesc */
+   Assert(rsi->expectedDesc);
+   call_state->ret_tupdesc = rsi->expectedDesc;
+
+   /*
+    * Switch to the right memory context and resource owner for storing the
+    * tuplestore. If we're within a subtransaction opened for an exception
+    * block, for example, we must still create the tuplestore in the resource
+    * owner that was active when this function was entered, and not in the
+    * subtransaction's resource owner.
+    */
+   oldcxt = MemoryContextSwitchTo(call_state->tuple_store_cxt);
+   oldowner = CurrentResourceOwner;
+   CurrentResourceOwner = call_state->tuple_store_owner;
+
+   call_state->tuple_store =
+       tuplestore_begin_heap(rsi->allowedModes & SFRM_Materialize_Random,
+                             false, work_mem);
+
+   /* Build attinmeta in this context, too */
+   call_state->attinmeta = TupleDescGetAttInMetadata(call_state->ret_tupdesc);
+
+   CurrentResourceOwner = oldowner;
+   MemoryContextSwitchTo(oldcxt);
+}
index a0a9619a9bb21f49a9f3346a4aacd8f309a3d609..0ebfe653406cb8afd94d0e91aa1ea78db1cd112e 100644 (file)
@@ -97,3 +97,36 @@ create temp table t1 (f1 int);
 select tcl_lastoid('t1');
 create temp table t2 (f1 int) with oids;
 select tcl_lastoid('t2') > 0;
+
+-- test some error cases
+CREATE FUNCTION tcl_error(OUT a int, OUT b int) AS $$return {$$ LANGUAGE pltcl;
+SELECT tcl_error();
+
+CREATE FUNCTION bad_record(OUT a text, OUT b text) AS $$return [list a]$$ LANGUAGE pltcl;
+SELECT bad_record();
+
+CREATE FUNCTION bad_field(OUT a text, OUT b text) AS $$return [list a 1 b 2 cow 3]$$ LANGUAGE pltcl;
+SELECT bad_field();
+
+-- test compound return
+select * from tcl_test_cube_squared(5);
+
+-- test SRF
+select * from tcl_test_squared_rows(0,5);
+
+select * from tcl_test_sequence(0,5) as a;
+
+select 1, tcl_test_sequence(0,5);
+
+CREATE FUNCTION non_srf() RETURNS int AS $$return_next 1$$ LANGUAGE pltcl;
+select non_srf();
+
+CREATE FUNCTION bad_record_srf(OUT a text, OUT b text) RETURNS SETOF record AS $$
+return_next [list a]
+$$ LANGUAGE pltcl;
+SELECT bad_record_srf();
+
+CREATE FUNCTION bad_field_srf(OUT a text, OUT b text) RETURNS SETOF record AS $$
+return_next [list a 1 b 2 cow 3]
+$$ LANGUAGE pltcl;
+SELECT bad_field_srf();
index 8df65a581655076a971d42367e09d59e21c14749..58f38d53aa4296aeab95dbe5f3e54add69f02afb 100644 (file)
@@ -596,6 +596,22 @@ drop table foo;
 drop event trigger tcl_a_snitch;
 drop event trigger tcl_b_snitch;
 
+CREATE FUNCTION tcl_test_cube_squared(in int, out squared int, out cubed int) AS $$
+    return [list squared [expr {$1 * $1}] cubed [expr {$1 * $1 * $1}]]
+$$ language pltcl;
+
+CREATE FUNCTION tcl_test_squared_rows(int,int) RETURNS TABLE (x int, y int) AS $$
+    for {set i $1} {$i < $2} {incr i} {
+        return_next [list y [expr {$i * $i}] x $i]
+    }
+$$ language pltcl;
+
+CREATE FUNCTION tcl_test_sequence(int,int) RETURNS SETOF int AS $$
+    for {set i $1} {$i < $2} {incr i} {
+        return_next $i
+    }
+$$ language pltcl;
+
 -- test use of errorCode in error handling
 
 create function tcl_error_handling_test() returns text as $$