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statement.cpp
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statement.cpp
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//
// Copyright (C) 2004-2008 Maciej Sobczak, Stephen Hutton
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
#define SOCI_POSTGRESQL_SOURCE
#include "soci/postgresql/soci-postgresql.h"
#include "soci/soci-platform.h"
#include <libpq/libpq-fs.h> // libpq
#include <cctype>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <sstream>
#ifdef SOCI_POSTGRESQL_NOPARAMS
#ifndef SOCI_POSTGRESQL_NOBINDBYNAME
#define SOCI_POSTGRESQL_NOBINDBYNAME
#endif // SOCI_POSTGRESQL_NOBINDBYNAME
#endif // SOCI_POSTGRESQL_NOPARAMS
using namespace soci;
using namespace soci::details;
namespace // unnamed
{
// used only with asynchronous operations in single-row mode
void wait_until_operation_complete(PGconn * conn)
{
while (true)
{
PGresult * result = PQgetResult(conn);
if (result == NULL)
{
break;
}
else
{
PQclear(result);
}
}
}
void throw_soci_error(PGconn * conn, const char * msg)
{
std::string description = msg;
description += ": ";
description += PQerrorMessage(conn);
throw soci_error(description);
}
} // unnamed namespace
postgresql_statement_backend::postgresql_statement_backend(
postgresql_session_backend &session, bool single_row_mode)
: session_(session), single_row_mode_(single_row_mode),
result_(session, NULL),
rowsAffectedBulk_(-1LL), justDescribed_(false),
hasIntoElements_(false), hasVectorIntoElements_(false),
hasUseElements_(false), hasVectorUseElements_(false)
{
}
postgresql_statement_backend::~postgresql_statement_backend()
{
if (statementName_.empty() == false)
{
try
{
session_.deallocate_prepared_statement(statementName_);
}
catch (...)
{
// Don't allow exceptions to escape from dtor. Suppressing them is
// not ideal, but terminating the program, as would happen if we're
// already unwinding the stack because of a previous exception,
// would be even worse.
}
}
}
void postgresql_statement_backend::alloc()
{
// nothing to do here
}
void postgresql_statement_backend::clean_up()
{
// 'reset' the value for a
// potential new execution.
rowsAffectedBulk_ = -1;
// nothing to do here
}
void postgresql_statement_backend::prepare(std::string const & query,
statement_type stType)
{
#ifdef SOCI_POSTGRESQL_NOBINDBYNAME
query_ = query;
#else
// rewrite the query by transforming all named parameters into
// the postgresql_ numbers ones (:abc -> $1, etc.)
enum { normal, in_quotes, in_name } state = normal;
std::string name;
int position = 1;
for (std::string::const_iterator it = query.begin(), end = query.end();
it != end; ++it)
{
switch (state)
{
case normal:
if (*it == '\'')
{
query_ += *it;
state = in_quotes;
}
else if (*it == ':')
{
// Check whether this is a cast operator (e.g. 23::float)
// and treat it as a special case, not as a named binding
const std::string::const_iterator next_it = it + 1;
if ((next_it != end) && (*next_it == ':'))
{
query_ += "::";
++it;
}
// Check whether this is an assignment(e.g. x:=y)
// and treat it as a special case, not as a named binding
else if ((next_it != end) && (*next_it == '='))
{
query_ += ":=";
++it;
}
else
{
state = in_name;
}
}
else // regular character, stay in the same state
{
query_ += *it;
}
break;
case in_quotes:
if (*it == '\'')
{
query_ += *it;
state = normal;
}
else // regular quoted character
{
query_ += *it;
}
break;
case in_name:
if (std::isalnum(*it) || *it == '_')
{
name += *it;
}
else // end of name
{
names_.push_back(name);
name.clear();
std::ostringstream ss;
ss << '$' << position++;
query_ += ss.str();
query_ += *it;
state = normal;
// Check whether the named parameter is immediatelly
// followed by a cast operator (e.g. :name::float)
// and handle the additional colon immediately to avoid
// its misinterpretation later on.
if (*it == ':')
{
const std::string::const_iterator next_it = it + 1;
if ((next_it != end) && (*next_it == ':'))
{
query_ += ':';
++it;
}
}
}
break;
}
}
if (state == in_name)
{
names_.push_back(name);
std::ostringstream ss;
ss << '$' << position++;
query_ += ss.str();
}
#endif // SOCI_POSTGRESQL_NOBINDBYNAME
#ifndef SOCI_POSTGRESQL_NOPREPARE
if (stType == st_repeatable_query)
{
if (!statementName_.empty())
{
throw soci_error("Shouldn't already have a prepared statement.");
}
// Holding the name temporarily in this var because
// if it fails to prepare it we can't DEALLOCATE it.
std::string statementName = session_.get_next_statement_name();
if (single_row_mode_)
{
// prepare for single-row retrieval
int result = PQsendPrepare(session_.conn_, statementName.c_str(),
query_.c_str(), static_cast<int>(names_.size()), NULL);
if (result != 1)
{
throw_soci_error(session_.conn_,
"Cannot prepare statement in singlerow mode");
}
wait_until_operation_complete(session_.conn_);
}
else
{
// default multi-row query execution
postgresql_result result(session_,
PQprepare(session_.conn_, statementName.c_str(),
query_.c_str(), static_cast<int>(names_.size()), NULL));
result.check_for_errors("Cannot prepare statement.");
}
// Now it's safe to save this info.
statementName_ = statementName;
}
stType_ = stType;
#endif // SOCI_POSTGRESQL_NOPREPARE
}
statement_backend::exec_fetch_result
postgresql_statement_backend::execute(int number)
{
if (single_row_mode_ && (number > 1))
{
throw soci_error("Bulk operations are not supported with single-row mode.");
}
// If the statement was "just described", then we know that
// it was actually executed with all the use elements
// already bound and pre-used. This means that the result of the
// query is already on the client side, so there is no need
// to re-execute it.
// The optimization based on the existing results
// from the row description can be performed only once.
// If the same statement is re-executed,
// it will be *really* re-executed, without reusing existing data.
if (justDescribed_ == false)
{
// This object could have been already filled with data before.
clean_up();
if ((number > 1) && hasIntoElements_)
{
throw soci_error(
"Bulk use with single into elements is not supported.");
}
// Since the bulk operations are not natively supported by postgresql_,
// we have to explicitly loop to achieve the bulk operations.
// On the other hand, looping is not needed if there are single
// use elements, even if there is a bulk fetch.
// We know that single use and bulk use elements in the same query are
// not supported anyway, so in the effect the 'number' parameter here
// specifies the size of vectors (into/use), but 'numberOfExecutions'
// specifies the number of loops that need to be performed.
int numberOfExecutions = 1;
if (number > 0)
{
numberOfExecutions = hasUseElements_ ? 1 : number;
}
if ((useByPosBuffers_.empty() == false) ||
(useByNameBuffers_.empty() == false))
{
if ((useByPosBuffers_.empty() == false) &&
(useByNameBuffers_.empty() == false))
{
throw soci_error(
"Binding for use elements must be either by position "
"or by name.");
}
long long rowsAffectedBulkTemp = 0;
for (int i = 0; i != numberOfExecutions; ++i)
{
std::vector<char *> paramValues;
if (useByPosBuffers_.empty() == false)
{
// use elements bind by position
// the map of use buffers can be traversed
// in its natural order
for (UseByPosBuffersMap::iterator
it = useByPosBuffers_.begin(),
end = useByPosBuffers_.end();
it != end; ++it)
{
char ** buffers = it->second;
paramValues.push_back(buffers[i]);
}
}
else
{
// use elements bind by name
for (std::vector<std::string>::iterator
it = names_.begin(), end = names_.end();
it != end; ++it)
{
UseByNameBuffersMap::iterator b
= useByNameBuffers_.find(*it);
if (b == useByNameBuffers_.end())
{
std::string msg(
"Missing use element for bind by name (");
msg += *it;
msg += ").";
throw soci_error(msg);
}
char ** buffers = b->second;
paramValues.push_back(buffers[i]);
}
}
#ifdef SOCI_POSTGRESQL_NOPARAMS
throw soci_error("Queries with parameters are not supported.");
#else
#ifdef SOCI_POSTGRESQL_NOPREPARE
if (single_row_mode_)
{
int result = PQsendQueryParams(
session_.conn_, query_.c_str(),
static_cast<int>(paramValues.size()),
NULL, ¶mValues[0], NULL, NULL, 0);
if (result != 1)
{
throw_soci_error(session_.conn_,
"Cannot execute query in single-row mode");
}
result = PQsetSingleRowMode(session_.conn_);
if (result != 1)
{
throw_soci_error(session_.conn_,
"cannot set singlerow mode");
}
}
else
{
// default multi-row execution
result_.reset(PQexecParams(session_.conn_, query_.c_str(),
static_cast<int>(paramValues.size()),
NULL, ¶mValues[0], NULL, NULL, 0));
}
#else
if (stType_ == st_repeatable_query)
{
// this query was separately prepared
if (single_row_mode_)
{
int result = PQsendQueryPrepared(session_.conn_,
statementName_.c_str(),
static_cast<int>(paramValues.size()),
¶mValues[0], NULL, NULL, 0);
if (result != 1)
{
throw_soci_error(session_.conn_,
"Cannot execute prepared query in single-row mode");
}
result = PQsetSingleRowMode(session_.conn_);
if (result != 1)
{
throw_soci_error(session_.conn_,
"Cannot set singlerow mode");
}
}
else
{
// default multi-row execution
result_.reset(PQexecPrepared(session_.conn_,
statementName_.c_str(),
static_cast<int>(paramValues.size()),
¶mValues[0], NULL, NULL, 0));
}
}
else // stType_ == st_one_time_query
{
// this query was not separately prepared and should
// be executed as a one-time query
if (single_row_mode_)
{
int result = PQsendQueryParams(session_.conn_, query_.c_str(),
static_cast<int>(paramValues.size()),
NULL, ¶mValues[0], NULL, NULL, 0);
if (result != 1)
{
throw_soci_error(session_.conn_,
"cannot execute query in single-row mode");
}
result = PQsetSingleRowMode(session_.conn_);
if (result != 1)
{
throw_soci_error(session_.conn_,
"Cannot set singlerow mode");
}
}
else
{
// default multi-row execution
result_.reset(PQexecParams(session_.conn_, query_.c_str(),
static_cast<int>(paramValues.size()),
NULL, ¶mValues[0], NULL, NULL, 0));
}
}
#endif // SOCI_POSTGRESQL_NOPREPARE
#endif // SOCI_POSTGRESQL_NOPARAMS
if (numberOfExecutions > 1)
{
// there are only bulk use elements (no intos)
// preserve the number of rows affected so far.
rowsAffectedBulk_ = rowsAffectedBulkTemp;
result_.check_for_errors("Cannot execute query.");
rowsAffectedBulkTemp += get_affected_rows();
}
}
rowsAffectedBulk_ = rowsAffectedBulkTemp;
if (numberOfExecutions > 1)
{
// it was a bulk operation
result_.reset();
return ef_no_data;
}
// otherwise (no bulk), follow the code below
}
else
{
// there are no use elements
// - execute the query without parameter information
#ifdef SOCI_POSTGRESQL_NOPREPARE
if (single_row_mode_)
{
int result = PQsendQuery(session_.conn_, query_.c_str());
if (result != 1)
{
throw_soci_error(session_.conn_,
"Cannot execute query in single-row mode");
}
result = PQsetSingleRowMode(session_.conn_);
if (result != 1)
{
throw_soci_error(session_.conn_,
"Cannot set single-row mode");
}
}
else
{
// default multi-row execution
result_.reset(PQexec(session_.conn_, query_.c_str()));
}
#else
if (stType_ == st_repeatable_query)
{
// this query was separately prepared
if (single_row_mode_)
{
int result = PQsendQueryPrepared(session_.conn_,
statementName_.c_str(), 0, NULL, NULL, NULL, 0);
if (result != 1)
{
throw_soci_error(session_.conn_,
"Cannot execute prepared query in single-row mode");
}
result = PQsetSingleRowMode(session_.conn_);
if (result != 1)
{
throw_soci_error(session_.conn_,
"Cannot set singlerow mode");
}
}
else
{
// default multi-row execution
result_.reset(PQexecPrepared(session_.conn_,
statementName_.c_str(), 0, NULL, NULL, NULL, 0));
}
}
else // stType_ == st_one_time_query
{
if (single_row_mode_)
{
int result = PQsendQuery(session_.conn_, query_.c_str());
if (result != 1)
{
throw_soci_error(session_.conn_,
"Cannot execute query in single-row mode");
}
result = PQsetSingleRowMode(session_.conn_);
if (result != 1)
{
throw_soci_error(session_.conn_,
"Cannot set single-row mode");
}
}
else
{
// default multi-row execution
result_.reset(PQexec(session_.conn_, query_.c_str()));
}
}
#endif // SOCI_POSTGRESQL_NOPREPARE
}
}
bool process_result;
if (single_row_mode_)
{
if (justDescribed_)
{
// reuse the result_ that was already filled when executing the query
// for the purpose of row describe
}
else
{
PGresult * res = PQgetResult(session_.conn_);
result_.reset(res);
}
process_result = result_.get_result() != NULL;
}
else
{
// default multi-row execution
process_result = result_.check_for_data("Cannot execute query.");
}
justDescribed_ = false;
if (process_result)
{
currentRow_ = 0;
rowsToConsume_ = 0;
numberOfRows_ = PQntuples(result_);
if (numberOfRows_ == 0)
{
return ef_no_data;
}
else
{
if (number > 0)
{
// prepare for the subsequent data consumption
return fetch(number);
}
else
{
// execute(0) was meant to only perform the query
return ef_success;
}
}
}
else
{
return ef_no_data;
}
}
statement_backend::exec_fetch_result
postgresql_statement_backend::fetch(int number)
{
if (single_row_mode_ && (number > 1))
{
throw soci_error("Bulk operations are not supported with single-row mode.");
}
// Note:
// In the multi-row mode this function does not actually fetch anything from anywhere
// - the data was already retrieved from the server in the execute()
// function, and the actual consumption of this data will take place
// in the postFetch functions, called for each into element.
// Here, we only prepare for this to happen (to emulate "the Oracle way").
// In the single-row mode the fetch of single row of data is performed as expected.
// forward the "cursor" from the last fetch
currentRow_ += rowsToConsume_;
if (currentRow_ >= numberOfRows_)
{
if (single_row_mode_)
{
PGresult* res = PQgetResult(session_.conn_);
result_.reset(res);
if (res == NULL)
{
return ef_no_data;
}
currentRow_ = 0;
rowsToConsume_ = 0;
numberOfRows_ = PQntuples(result_);
if (numberOfRows_ == 0)
{
return ef_no_data;
}
else
{
rowsToConsume_ = 1;
return ef_success;
}
}
else
{
// default multi-row execution
// all rows were already consumed
return ef_no_data;
}
}
else
{
if (currentRow_ + number > numberOfRows_)
{
if (single_row_mode_)
{
rowsToConsume_ = 1;
return ef_success;
}
else
{
// default multi-row execution
rowsToConsume_ = numberOfRows_ - currentRow_;
// this simulates the behaviour of Oracle
// - when EOF is hit, we return ef_no_data even when there are
// actually some rows fetched
return ef_no_data;
}
}
else
{
if (single_row_mode_)
{
rowsToConsume_ = 1;
}
else
{
rowsToConsume_ = number;
}
return ef_success;
}
}
}
long long postgresql_statement_backend::get_affected_rows()
{
// PQcmdTuples() doesn't really modify the result but it takes a non-const
// pointer to it, so we can't rely on implicit conversion here.
const char * const resultStr = PQcmdTuples(result_.get_result());
char * end;
long long result = std::strtoll(resultStr, &end, 0);
if (end != resultStr)
{
return result;
}
else if (rowsAffectedBulk_ >= 0)
{
return rowsAffectedBulk_;
}
else
{
return -1;
}
}
int postgresql_statement_backend::get_number_of_rows()
{
return numberOfRows_ - currentRow_;
}
std::string postgresql_statement_backend::get_parameter_name(int index) const
{
return names_.at(index);
}
std::string postgresql_statement_backend::rewrite_for_procedure_call(
std::string const & query)
{
std::string newQuery("select ");
newQuery += query;
return newQuery;
}
int postgresql_statement_backend::prepare_for_describe()
{
execute(1);
justDescribed_ = true;
int columns = PQnfields(result_);
return columns;
}
void postgresql_statement_backend::describe_column(int colNum, data_type & type,
std::string & columnName)
{
// In postgresql_ column numbers start from 0
int const pos = colNum - 1;
unsigned long const typeOid = PQftype(result_, pos);
switch (typeOid)
{
// Note: the following list of OIDs was taken from the pg_type table
// we do not claim that this list is exchaustive or even correct.
// from pg_type:
case 25: // text
case 1043: // varchar
case 2275: // cstring
case 18: // char
case 1042: // bpchar
case 142: // xml
case 114: // json
case 17: // bytea
case 2950: // uuid
type = dt_string;
break;
case 702: // abstime
case 703: // reltime
case 1082: // date
case 1083: // time
case 1114: // timestamp
case 1184: // timestamptz
case 1266: // timetz
type = dt_date;
break;
case 700: // float4
case 701: // float8
case 1700: // numeric
type = dt_double;
break;
case 16: // bool
case 21: // int2
case 23: // int4
case 26: // oid
type = dt_integer;
break;
case 20: // int8
type = dt_long_long;
break;
default:
{
int form = PQfformat(result_, pos);
int size = PQfsize(result_, pos);
if (form == 0 && size == -1)
{
type = dt_string;
}
else
{
std::stringstream message;
message << "unknown data type with typelem: " << typeOid
<< " for colNum: " << colNum
<< " with name: " << PQfname(result_, pos);
throw soci_error(message.str());
}
}
}
columnName = PQfname(result_, pos);
}
postgresql_standard_into_type_backend *
postgresql_statement_backend::make_into_type_backend()
{
hasIntoElements_ = true;
return new postgresql_standard_into_type_backend(*this);
}
postgresql_standard_use_type_backend *
postgresql_statement_backend::make_use_type_backend()
{
hasUseElements_ = true;
return new postgresql_standard_use_type_backend(*this);
}
postgresql_vector_into_type_backend *
postgresql_statement_backend::make_vector_into_type_backend()
{
hasVectorIntoElements_ = true;
return new postgresql_vector_into_type_backend(*this);
}
postgresql_vector_use_type_backend *
postgresql_statement_backend::make_vector_use_type_backend()
{
hasVectorUseElements_ = true;
return new postgresql_vector_use_type_backend(*this);
}