PostgreSQL服务端开发学习 -- fmgr.h

typedefstructFunctionCallInfoBaseData*FunctionCallInfo;
typedefDatum (*PGFunction) (FunctionCallInfofcinfo);

Datumpgpool_recovery(PG_FUNCTION_ARGS)

typedefstructFmgrInfo{
PGFunctionfn_addr;        /* pointer to function or handler to be called */Oidfn_oid;         /* OID of function (NOT of handler, if any) */shortfn_nargs;       /* number of input args (0..FUNC_MAX_ARGS) */boolfn_strict;      /* function is "strict" (NULL in => NULL out) */boolfn_retset;      /* function returns a set */unsignedcharfn_stats;     /* collect stats if track_functions > this */void*fn_extra;       /* extra space for use by handler */MemoryContextfn_mcxt;      /* memory context to store fn_extra in */fmNodePtrfn_expr;        /* expression parse tree for call, or NULL */} FmgrInfo;

typedefstructFunctionCallInfoBaseData{
FmgrInfo*flinfo;         /* ptr to lookup info used for this call */fmNodePtrcontext;        /* pass info about context of call */fmNodePtrresultinfo;     /* pass or return extra info about result */Oidfncollation;    /* collation for function to use */#define FIELDNO_FUNCTIONCALLINFODATA_ISNULL 4boolisnull;         /* function must set true if result is NULL */shortnargs;          /* # arguments actually passed */#define FIELDNO_FUNCTIONCALLINFODATA_ARGS 6NullableDatumargs[FLEXIBLE_ARRAY_MEMBER];
} FunctionCallInfoBaseData;

#define InitFunctionCallInfoData(Fcinfo, Flinfo, Nargs, Collation, Context, Resultinfo) \do { \(Fcinfo).flinfo = (Flinfo); \(Fcinfo).context = (Context); \(Fcinfo).resultinfo = (Resultinfo); \(Fcinfo).fncollation = (Collation); \(Fcinfo).isnull = false; \(Fcinfo).nargs = (Nargs); \} while (0)

#define FunctionCallInvoke(fcinfo)  ((* (fcinfo)->flinfo->fn_addr) (fcinfo))

Datumfunction_name(PG_FUNCTION_ARGS)
{
    ...
}

/* fmgr兼容函数标准参数列表 */#define PG_FUNCTION_ARGS    FunctionCallInfo fcinfo/** 取得字符集*/#define PG_GET_COLLATION()  (fcinfo->fncollation)/** 取得参数个数*/#define PG_NARGS() (fcinfo->nargs)/** 参数是否为空*/#define PG_ARGISNULL(n)  (fcinfo->args[n].isnull)

#define PG_GETARG_DATUM(n)   (fcinfo->args[n].value)#define PG_GETARG_INT32(n)   DatumGetInt32(PG_GETARG_DATUM(n))#define PG_GETARG_UINT32(n)  DatumGetUInt32(PG_GETARG_DATUM(n))#define PG_GETARG_INT16(n)   DatumGetInt16(PG_GETARG_DATUM(n))#define PG_GETARG_UINT16(n)  DatumGetUInt16(PG_GETARG_DATUM(n))#define PG_GETARG_CHAR(n)    DatumGetChar(PG_GETARG_DATUM(n))#define PG_GETARG_BOOL(n)    DatumGetBool(PG_GETARG_DATUM(n))#define PG_GETARG_OID(n)     DatumGetObjectId(PG_GETARG_DATUM(n))#define PG_GETARG_POINTER(n) DatumGetPointer(PG_GETARG_DATUM(n))#define PG_GETARG_CSTRING(n) DatumGetCString(PG_GETARG_DATUM(n))#define PG_GETARG_NAME(n)    DatumGetName(PG_GETARG_DATUM(n))#define PG_GETARG_TRANSACTIONID(n)  DatumGetTransactionId(PG_GETARG_DATUM(n))/* these macros hide the pass-by-reference-ness of the datatype: */#define PG_GETARG_FLOAT4(n)  DatumGetFloat4(PG_GETARG_DATUM(n))#define PG_GETARG_FLOAT8(n)  DatumGetFloat8(PG_GETARG_DATUM(n))#define PG_GETARG_INT64(n)   DatumGetInt64(PG_GETARG_DATUM(n))/* use this if you want the raw, possibly-toasted input datum: */#define PG_GETARG_RAW_VARLENA_P(n)  ((struct varlena *) PG_GETARG_POINTER(n))/* use this if you want the input datum de-toasted: */#define PG_GETARG_VARLENA_P(n) PG_DETOAST_DATUM(PG_GETARG_DATUM(n))/* and this if you can handle 1-byte-header datums: */#define PG_GETARG_VARLENA_PP(n) PG_DETOAST_DATUM_PACKED(PG_GETARG_DATUM(n))/* DatumGetFoo macros for varlena types will typically look like this: */#define DatumGetByteaPP(X)          ((bytea *) PG_DETOAST_DATUM_PACKED(X))#define DatumGetTextPP(X)           ((text *) PG_DETOAST_DATUM_PACKED(X))#define DatumGetBpCharPP(X)         ((BpChar *) PG_DETOAST_DATUM_PACKED(X))#define DatumGetVarCharPP(X)        ((VarChar *) PG_DETOAST_DATUM_PACKED(X))#define DatumGetHeapTupleHeader(X)  ((HeapTupleHeader) PG_DETOAST_DATUM(X))/* And we also offer variants that return an OK-to-write copy */#define DatumGetByteaPCopy(X)       ((bytea *) PG_DETOAST_DATUM_COPY(X))#define DatumGetTextPCopy(X)        ((text *) PG_DETOAST_DATUM_COPY(X))#define DatumGetBpCharPCopy(X)      ((BpChar *) PG_DETOAST_DATUM_COPY(X))#define DatumGetVarCharPCopy(X)     ((VarChar *) PG_DETOAST_DATUM_COPY(X))#define DatumGetHeapTupleHeaderCopy(X)  ((HeapTupleHeader) PG_DETOAST_DATUM_COPY(X))/* Variants which return n bytes starting at pos. m */#define DatumGetByteaPSlice(X,m,n)  ((bytea *) PG_DETOAST_DATUM_SLICE(X,m,n))#define DatumGetTextPSlice(X,m,n)   ((text *) PG_DETOAST_DATUM_SLICE(X,m,n))#define DatumGetBpCharPSlice(X,m,n) ((BpChar *) PG_DETOAST_DATUM_SLICE(X,m,n))#define DatumGetVarCharPSlice(X,m,n) ((VarChar *) PG_DETOAST_DATUM_SLICE(X,m,n))/* GETARG macros for varlena types will typically look like this: */#define PG_GETARG_BYTEA_PP(n)       DatumGetByteaPP(PG_GETARG_DATUM(n))#define PG_GETARG_TEXT_PP(n)        DatumGetTextPP(PG_GETARG_DATUM(n))#define PG_GETARG_BPCHAR_PP(n)      DatumGetBpCharPP(PG_GETARG_DATUM(n))#define PG_GETARG_VARCHAR_PP(n)     DatumGetVarCharPP(PG_GETARG_DATUM(n))#define PG_GETARG_HEAPTUPLEHEADER(n)    DatumGetHeapTupleHeader(PG_GETARG_DATUM(n))/* And we also offer variants that return an OK-to-write copy */#define PG_GETARG_BYTEA_P_COPY(n)   DatumGetByteaPCopy(PG_GETARG_DATUM(n))#define PG_GETARG_TEXT_P_COPY(n)    DatumGetTextPCopy(PG_GETARG_DATUM(n))#define PG_GETARG_BPCHAR_P_COPY(n)  DatumGetBpCharPCopy(PG_GETARG_DATUM(n))#define PG_GETARG_VARCHAR_P_COPY(n) DatumGetVarCharPCopy(PG_GETARG_DATUM(n))#define PG_GETARG_HEAPTUPLEHEADER_COPY(n)   DatumGetHeapTupleHeaderCopy(PG_GETARG_DATUM(n))/* And a b-byte slice from position a -also OK to write */#define PG_GETARG_BYTEA_P_SLICE(n,a,b) DatumGetByteaPSlice(PG_GETARG_DATUM(n),a,b)#define PG_GETARG_TEXT_P_SLICE(n,a,b)  DatumGetTextPSlice(PG_GETARG_DATUM(n),a,b)#define PG_GETARG_BPCHAR_P_SLICE(n,a,b) DatumGetBpCharPSlice(PG_GETARG_DATUM(n),a,b)#define PG_GETARG_VARCHAR_P_SLICE(n,a,b) DatumGetVarCharPSlice(PG_GETARG_DATUM(n),a,b)

#define DatumGetByteaP(X)           ((bytea *) PG_DETOAST_DATUM(X))#define DatumGetTextP(X)            ((text *) PG_DETOAST_DATUM(X))#define DatumGetBpCharP(X)          ((BpChar *) PG_DETOAST_DATUM(X))#define DatumGetVarCharP(X)         ((VarChar *) PG_DETOAST_DATUM(X))#define PG_GETARG_BYTEA_P(n)        DatumGetByteaP(PG_GETARG_DATUM(n))#define PG_GETARG_TEXT_P(n)         DatumGetTextP(PG_GETARG_DATUM(n))#define PG_GETARG_BPCHAR_P(n)       DatumGetBpCharP(PG_GETARG_DATUM(n))#define PG_GETARG_VARCHAR_P(n)      DatumGetVarCharP(PG_GETARG_DATUM(n))

#define PG_RETURN_DATUM(x)   return (x)#define PG_RETURN_INT32(x)   return Int32GetDatum(x)#define PG_RETURN_UINT32(x)  return UInt32GetDatum(x)#define PG_RETURN_INT16(x)   return Int16GetDatum(x)#define PG_RETURN_UINT16(x)  return UInt16GetDatum(x)#define PG_RETURN_CHAR(x)    return CharGetDatum(x)#define PG_RETURN_BOOL(x)    return BoolGetDatum(x)#define PG_RETURN_OID(x)     return ObjectIdGetDatum(x)#define PG_RETURN_POINTER(x) return PointerGetDatum(x)#define PG_RETURN_CSTRING(x) return CStringGetDatum(x)#define PG_RETURN_NAME(x)    return NameGetDatum(x)#define PG_RETURN_TRANSACTIONID(x)  return TransactionIdGetDatum(x)/* these macros hide the pass-by-reference-ness of the datatype: */#define PG_RETURN_FLOAT4(x)  return Float4GetDatum(x)#define PG_RETURN_FLOAT8(x)  return Float8GetDatum(x)#define PG_RETURN_INT64(x)   return Int64GetDatum(x)#define PG_RETURN_UINT64(x)  return UInt64GetDatum(x)/* RETURN macros for other pass-by-ref types will typically look like this: */#define PG_RETURN_BYTEA_P(x)   PG_RETURN_POINTER(x)#define PG_RETURN_TEXT_P(x)    PG_RETURN_POINTER(x)#define PG_RETURN_BPCHAR_P(x)  PG_RETURN_POINTER(x)#define PG_RETURN_VARCHAR_P(x) PG_RETURN_POINTER(x)#define PG_RETURN_HEAPTUPLEHEADER(x)  return HeapTupleHeaderGetDatum(x)

#define DirectFunctionCall1(func, arg1) \DirectFunctionCall1Coll(func, InvalidOid, arg1)#define DirectFunctionCall2(func, arg1, arg2) \DirectFunctionCall2Coll(func, InvalidOid, arg1, arg2)#define DirectFunctionCall3(func, arg1, arg2, arg3) \DirectFunctionCall3Coll(func, InvalidOid, arg1, arg2, arg3)#define DirectFunctionCall4(func, arg1, arg2, arg3, arg4) \DirectFunctionCall4Coll(func, InvalidOid, arg1, arg2, arg3, arg4)#define DirectFunctionCall5(func, arg1, arg2, arg3, arg4, arg5) \DirectFunctionCall5Coll(func, InvalidOid, arg1, arg2, arg3, arg4, arg5)#define DirectFunctionCall6(func, arg1, arg2, arg3, arg4, arg5, arg6) \DirectFunctionCall6Coll(func, InvalidOid, arg1, arg2, arg3, arg4, arg5, arg6)#define DirectFunctionCall7(func, arg1, arg2, arg3, arg4, arg5, arg6, arg7) \DirectFunctionCall7Coll(func, InvalidOid, arg1, arg2, arg3, arg4, arg5, arg6, arg7)#define DirectFunctionCall8(func, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8) \DirectFunctionCall8Coll(func, InvalidOid, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8)#define DirectFunctionCall9(func, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9) \DirectFunctionCall9Coll(func, InvalidOid, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9)#define FunctionCall1(flinfo, arg1) \FunctionCall1Coll(flinfo, InvalidOid, arg1)#define FunctionCall2(flinfo, arg1, arg2) \FunctionCall2Coll(flinfo, InvalidOid, arg1, arg2)#define FunctionCall3(flinfo, arg1, arg2, arg3) \FunctionCall3Coll(flinfo, InvalidOid, arg1, arg2, arg3)#define FunctionCall4(flinfo, arg1, arg2, arg3, arg4) \FunctionCall4Coll(flinfo, InvalidOid, arg1, arg2, arg3, arg4)#define FunctionCall5(flinfo, arg1, arg2, arg3, arg4, arg5) \FunctionCall5Coll(flinfo, InvalidOid, arg1, arg2, arg3, arg4, arg5)#define FunctionCall6(flinfo, arg1, arg2, arg3, arg4, arg5, arg6) \FunctionCall6Coll(flinfo, InvalidOid, arg1, arg2, arg3, arg4, arg5, arg6)#define FunctionCall7(flinfo, arg1, arg2, arg3, arg4, arg5, arg6, arg7) \FunctionCall7Coll(flinfo, InvalidOid, arg1, arg2, arg3, arg4, arg5, arg6, arg7)#define FunctionCall8(flinfo, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8) \FunctionCall8Coll(flinfo, InvalidOid, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8)#define FunctionCall9(flinfo, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9) \FunctionCall9Coll(flinfo, InvalidOid, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9)#define OidFunctionCall0(functionId) \OidFunctionCall0Coll(functionId, InvalidOid)#define OidFunctionCall1(functionId, arg1) \OidFunctionCall1Coll(functionId, InvalidOid, arg1)#define OidFunctionCall2(functionId, arg1, arg2) \OidFunctionCall2Coll(functionId, InvalidOid, arg1, arg2)#define OidFunctionCall3(functionId, arg1, arg2, arg3) \OidFunctionCall3Coll(functionId, InvalidOid, arg1, arg2, arg3)#define OidFunctionCall4(functionId, arg1, arg2, arg3, arg4) \OidFunctionCall4Coll(functionId, InvalidOid, arg1, arg2, arg3, arg4)#define OidFunctionCall5(functionId, arg1, arg2, arg3, arg4, arg5) \OidFunctionCall5Coll(functionId, InvalidOid, arg1, arg2, arg3, arg4, arg5)#define OidFunctionCall6(functionId, arg1, arg2, arg3, arg4, arg5, arg6) \OidFunctionCall6Coll(functionId, InvalidOid, arg1, arg2, arg3, arg4, arg5, arg6)#define OidFunctionCall7(functionId, arg1, arg2, arg3, arg4, arg5, arg6, arg7) \OidFunctionCall7Coll(functionId, InvalidOid, arg1, arg2, arg3, arg4, arg5, arg6, arg7)#define OidFunctionCall8(functionId, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8) \OidFunctionCall8Coll(functionId, InvalidOid, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8)#define OidFunctionCall9(functionId, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9) \OidFunctionCall9Coll(functionId, InvalidOid, arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8, arg9)