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Results processing
[LibTDS API]

Handle tokens in packets. More...

Functions

int tds_process_login_tokens (TDSSOCKET *tds)
 tds_process_login_tokens() is called after sending the login packet to the server.

int tds_process_result_tokens (TDSSOCKET *tds, TDS_INT *result_type, int *done_flags)
 process TDS result-type message streams.

int tds_process_row_tokens (TDSSOCKET *tds, TDS_INT *rowtype, TDS_INT *computeid)
 process TDS row-type message streams.

int tds_process_row_tokens_ct (TDSSOCKET *tds, TDS_INT *rowtype, TDS_INT *computeid)
int tds_process_trailing_tokens (TDSSOCKET *tds)
 tds_process_trailing_tokens() is called to discard messages that may be left unprocessed at the end of a result "batch".

int tds_process_simple_query (TDSSOCKET *tds)
 Process results for simple query as "SET TEXTSIZE" or "USE dbname" If the statement returns results, beware they are discarded.

int tds_do_until_done (TDSSOCKET *tds)
 simple flush function.

void tds_add_row_column_size (TDSRESULTINFO *info, TDSCOLUMN *curcol)
 Add a column size to result info row size and calc offset into row.

int tds_client_msg (TDSCONTEXT *tds_ctx, TDSSOCKET *tds, int msgnum, int level, int state, int line, const char *msg_text)
 tds_client_msg() sends a message to the client application from the CLI or TDS layer.

int tds_alloc_get_string (TDSSOCKET *tds, char **string, int len)
 Read a string from wire in a new allocated buffer.

int tds_process_cancel (TDSSOCKET *tds)
 tds_process_cancel() processes the incoming token stream until it finds an end token (DONE, DONEPROC, DONEINPROC) with the cancel flag set.

void tds_set_null (unsigned char *current_row, int column)
 set the null bit for the given column in the row buffer

void tds_clr_null (unsigned char *current_row, int column)
 clear the null bit for the given column in the row buffer

int tds_get_null (unsigned char *current_row, int column)
 Return the null bit for the given column in the row buffer.

TDSDYNAMIC * tds_lookup_dynamic (TDSSOCKET *tds, char *id)
 Find a dynamic given string id.

int tds_get_token_size (int marker)
 tds_get_token_size() returns the size of a fixed length token used by tds_process_cancel() to determine how to read past a token

void tds_swap_datatype (int coltype, unsigned char *buf)
int tds5_send_optioncmd (TDSSOCKET *tds, TDS_OPTION_CMD tds_command, TDS_OPTION tds_option, TDS_OPTION_ARG *ptds_argument, TDS_INT *ptds_argsize)
const char * tds_prtype (int token)

Detailed Description

Handle tokens in packets.

Many PDU (packets data unit) contain tokens. (like result description, rows, data, errors and many other).


Function Documentation

void tds_add_row_column_size TDSRESULTINFO info,
TDSCOLUMN curcol
 

Add a column size to result info row size and calc offset into row.

Parameters:
info result where to add column
curcol column to add

int tds_alloc_get_string TDSSOCKET *  tds,
char **  string,
int  len
 

Read a string from wire in a new allocated buffer.

Parameters:
len length of string to read

int tds_client_msg TDSCONTEXT *  tds_ctx,
TDSSOCKET *  tds,
int  msgnum,
int  level,
int  state,
int  line,
const char *  msg_text
 

tds_client_msg() sends a message to the client application from the CLI or TDS layer.

A client message is one that is generated from with the library and not from the server. The message is sent to the CLI (the err_handler) so that it may forward it to the client application or discard it if no msg handler has been by the application. tds->parent contains a void pointer to the parent of the tds socket. This can be cast back into DBPROCESS or CS_CONNECTION by the CLI and used to determine the proper recipient function for this message.

Todo:
This procedure is deprecated, because the client libraries use differing messages and message numbers. The general approach is to emit ct-lib error information and let db-lib and ODBC map that to their number and text.

int tds_do_until_done TDSSOCKET *  tds  ) 
 

simple flush function.

maybe be superseded soon.

TDSDYNAMIC* tds_lookup_dynamic TDSSOCKET *  tds,
char *  id
 

Find a dynamic given string id.

Returns:
dynamic or NULL is not found
Parameters:
id dynamic id to search

int tds_process_cancel TDSSOCKET *  tds  ) 
 

tds_process_cancel() processes the incoming token stream until it finds an end token (DONE, DONEPROC, DONEINPROC) with the cancel flag set.

a that point the connetion should be ready to handle a new query.

int tds_process_login_tokens TDSSOCKET *  tds  ) 
 

tds_process_login_tokens() is called after sending the login packet to the server.

It returns the success or failure of the login dependent on the protocol version. 4.2 sends an ACK token only when successful, TDS 5.0 sends it always with a success byte within

int tds_process_result_tokens TDSSOCKET *  tds,
TDS_INT *  result_type,
int *  done_flags
 

process TDS result-type message streams.

tds_process_result_tokens() is called after submitting a query with tds_submit_query() and is responsible for calling the routines to populate tds->res_info if appropriate (some query have no result sets)

Parameters:
tds A pointer to the TDSSOCKET structure managing a client/server operation.
result_type A pointer to an integer variable which tds_process_result_tokens sets to indicate the current type of result.
Values that indicate command status
TDS_DONE_RESULTThe results of a command have been completely processed. This command return no rows.
TDS_DONEPROC_RESULTThe results of a command have been completely processed. This command return rows.
TDS_DONEINPROC_RESULTThe results of a command have been completely processed. This command return rows.
Values that indicate results information is available
TDS_ROWFMT_RESULTRegular Data format information tds->res_info now contains the result details ; tds->current_results now points to that data
TDS_COMPUTEFMT_ RESULTCompute data format information tds->comp_info now contains the result data; tds->current_results now points to that data
TDS_DESCRIBE_RESULT
Values that indicate data is available
ValueMeaningInformation returned
TDS_ROW_RESULTRegular row results 1 or more rows of regular data can now be retrieved
TDS_COMPUTE_RESULTCompute row results A single row of compute data can now be retrieved
TDS_PARAM_RESULTReturn parameter results param_info or cur_dyn->params contain returned parameters
TDS_STATUS_RESULTStored procedure status results tds->ret_status contain the returned code
Todo:
Complete TDS_DESCRIBE_RESULT description
Return values:
TDS_SUCCEED if a result set is available for processing.
TDS_NO_MORE_RESULTS if all results have been completely processed.
Examples
The following code is cut from ct_results(), the ct-library function
done = 0;

    /* see what "result" tokens we have. a "result" in ct-lib terms also  */
    /* includes row data. Some result types always get reported back  to  */
    /* the calling program, others are only reported back if the relevant */
    /* config flag is set.                                                */

while (!done) {

        tdsret = tds_process_result_tokens(tds, &res_type, NULL);

        switch (tdsret) {

        case TDS_SUCCEED:

                cmd->curr_result_type = res_type;

                switch (res_type) {
                case TDS_COMPUTEFMT_RESULT:
                case TDS_ROWFMT_RESULT:
                        if (context->config.cs_expose_formats) {
                                done = 1;
                                retcode = CS_SUCCEED;
                                *result_type = res_type;
                        }
                        break;

                case TDS_COMPUTE_RESULT:
                        /* we've hit a compute data row. We have to get hold of this */
                        /* data now, as it's necessary  to tie this data back to its */
                        /* result format...the user may call ct_res_info() & friends */
                        /* after getting back a compute "result".                    */

                        tdsret = tds_process_row_tokens(tds, &rowtype, &computeid);

                        if (tdsret == TDS_SUCCEED) {
                                if (rowtype == TDS_COMP_ROW) {
                                        cmd->row_prefetched = 1;
                                        retcode = CS_SUCCEED;
                                } else {
                                        /* this couldn't really happen, but... */
                                        retcode = CS_FAIL;
                                }
                        } else
                                retcode = CS_FAIL;
                        done = 1;
                        *result_type = res_type;
                        break;

                case TDS_DONE_RESULT:
                case TDS_DONEPROC_RESULT:
                case TDS_DONEINPROC_RESULT:

                        /* there's a distinction in ct-library     */
                        /* depending on whether a command returned */
                        /* results or not...                          */

                        if (tds->res_info)
                                *result_type = CS_CMD_DONE;
                        else
                                *result_type = CS_CMD_SUCCEED;

                        retcode = CS_SUCCEED;
                        done = 1;
                        break;


                default:
                        retcode = CS_SUCCEED;
                        *result_type = res_type;
                        done = 1;
                        break;
                }
                break;

        case TDS_NO_MORE_RESULTS:
                done = 1;
                retcode = CS_END_RESULTS;
                break;
        case TDS_FAIL:
                done = 1;
                retcode = CS_FAIL;
                break;
        }
}

int tds_process_row_tokens TDSSOCKET *  tds,
TDS_INT *  rowtype,
TDS_INT *  computeid
 

process TDS row-type message streams.

tds_process_row_tokens() is called once a result set has been obtained with tds_process_result_tokens(). It calls tds_process_row() to copy data into the row buffer.

Parameters:
tds A pointer to the TDSSOCKET structure managing a client/server operation.
rowtype A pointer to an integer variable which tds_process_row_tokens sets to indicate the current type of row
computeid A pointer to an integer variable which tds_process_row_tokens sets to identify the compute_id of the row being returned. A compute row is a row that is generated by a compute clause. The compute_id matches the number of the compute row that was read; the first compute row is 1, the second is 2, and so forth.
Possible values of *rowtype
  • TDS_REG_ROW A regular data row
  • TDS_COMP_ROW A row of compute data
  • TDS_NO_MORE_ROWS There are no more rows of data in this result set
Return values:
TDS_SUCCEED A row of data is available for processing.
TDS_NO_MORE_ROWS All rows have been completely processed.
TDS_FAIL An unexpected error occurred
Examples
The following code is cut from dbnextrow(), the db-library function
if ((ret = tds_process_row_tokens(dbproc->tds_socket, &rowtype, &computeid))
    == TDS_SUCCEED) {
        if (rowtype == TDS_REG_ROW) {
                /* Add the row to the row buffer */
                resinfo = tds->current_results;
                buffer_add_row(&(dbproc->row_buf), resinfo->current_row,
                                        resinfo->row_size);
                result = REG_ROW;
        } else if (rowtype == TDS_COMP_ROW) {
                /* Add the row to the row buffer */
                resinfo = tds->current_results;
                buffer_add_row(&(dbproc->row_buf), resinfo->current_row,
                                        resinfo->row_size);
                result = computeid;
        } else
                result = FAIL;
} else if (ret == TDS_NO_MORE_ROWS) {
        result = NO_MORE_ROWS;
} else
        result = FAIL;

int tds_process_simple_query TDSSOCKET *  tds  ) 
 

Process results for simple query as "SET TEXTSIZE" or "USE dbname" If the statement returns results, beware they are discarded.

This function was written to avoid direct calls to tds_process_default_tokens (which caused problems such as ignoring query errors). Results are read until idle state or severe failure (do not stop for statement failure).

Returns:
see tds_process_result_tokens for results (TDS_NO_MORE_RESULTS is never returned)

int tds_process_trailing_tokens TDSSOCKET *  tds  ) 
 

tds_process_trailing_tokens() is called to discard messages that may be left unprocessed at the end of a result "batch".

In dblibrary, it is valid to process all the data rows that a command may have returned but to leave end tokens etc. unprocessed (at least explicitly) This function is called to discard such tokens. If it comes across a token that does not fall into the category of valid "trailing" tokens, it will return TDS_FAIL, allowing the calling dblibrary function to return a "results pending" message. The valid "trailing" tokens are :

TDS_DONE_TOKEN TDS_DONEPROC_TOKEN TDS_DONEINPROC_TOKEN TDS_RETURNSTATUS_TOKEN TDS_PARAM_TOKEN TDS5_PARAMFMT_TOKEN TDS5_PARAMS_TOKEN


Generated on Tue Mar 29 19:52:38 2005 for FreeTDS API by doxygen1.3