ZeroTierOne/ext/libpqxx-7.7.3/test/test84.cxx
2022-06-22 15:03:19 -07:00

110 lines
3.1 KiB
C++

#include <algorithm>
#include <cstdio>
#include <iostream>
#include <string>
#include <vector>
#include <pqxx/cursor>
#include <pqxx/transaction>
#include "test_helpers.hxx"
// "Adopted SQL Cursor" test program for libpqxx. Create SQL cursor, wrap it
// in a cursor stream, then use it to fetch data and check for consistent
// results. Compare results against an icursor_iterator so that is tested as
// well.
namespace
{
void test_084()
{
pqxx::connection conn;
pqxx::transaction<pqxx::serializable> tx{conn};
std::string const Table{"pg_tables"}, Key{"tablename"};
// Count rows.
pqxx::result R(tx.exec("SELECT count(*) FROM " + Table));
PQXX_CHECK(
R.at(0).at(0).as<long>() > 20,
"Not enough rows in " + Table + ", cannot test.");
// Create an SQL cursor and, for good measure, muddle up its state a bit.
std::string const CurName{"MYCUR"},
Query{"SELECT * FROM " + Table + " ORDER BY " + Key};
constexpr int InitialSkip{2}, GetRows{3};
tx.exec0("DECLARE " + tx.quote_name(CurName) + " CURSOR FOR " + Query);
tx.exec0(
"MOVE " + pqxx::to_string(InitialSkip * GetRows) +
" "
"IN " +
tx.quote_name(CurName));
// Wrap cursor in cursor stream. Apply some trickery to get its name inside
// a result field for this purpose. This isn't easy because it's not
// supposed to be easy; normally we'd only construct streams around existing
// SQL cursors if they were being returned by functions.
pqxx::icursorstream C{
tx, tx.exec("SELECT '" + tx.esc(CurName) + "'")[0][0], GetRows};
// Create parallel cursor to check results
pqxx::icursorstream C2{tx, Query, "CHECKCUR", GetRows};
pqxx::icursor_iterator i2{C2};
// Remember, our adopted cursor is at position (InitialSkip*GetRows)
pqxx::icursor_iterator i3(i2);
PQXX_CHECK(
(i3 == i2) and not(i3 != i2),
"Equality on copy-constructed icursor_iterator is broken.");
PQXX_CHECK(
not(i3 > i2) and not(i3 < i2) and (i3 <= i2) and (i3 >= i2),
"Comparison on identical icursor_iterators is broken.");
i3 += InitialSkip;
PQXX_CHECK(not(i3 <= i2), "icursor_iterator operator<=() is broken.");
pqxx::icursor_iterator iend, i4;
PQXX_CHECK(i3 != iend, "Early end to icursor_iterator iteration.");
i4 = iend;
PQXX_CHECK(i4 == iend, "Assigning empty icursor_iterator fails.");
// Now start testing our new Cursor.
C >> R;
i2 = i3;
pqxx::result R2(*i2++);
PQXX_CHECK_EQUAL(
std::size(R), static_cast<pqxx::result::size_type>(GetRows),
"Got unexpected number of rows.");
PQXX_CHECK_EQUAL(R, R2, "Unexpected result at [1]");
C.get(R);
R2 = *i2;
PQXX_CHECK_EQUAL(R, R2, "Unexpected result at [2]");
i2 += 1;
C.ignore(GetRows);
C.get(R);
R2 = *++i2;
PQXX_CHECK_EQUAL(R, R2, "Unexpected result at [3]");
++i2;
R2 = *i2++;
for (int i{1}; C.get(R) and i2 != iend; R2 = *i2++, ++i)
PQXX_CHECK_EQUAL(
R, R2, "Unexpected result in iteration at " + pqxx::to_string(i));
PQXX_CHECK(i2 == iend, "Adopted cursor terminated early.");
PQXX_CHECK(not(C >> R), "icursor_iterator terminated early.");
}
} // namespace
PQXX_REGISTER_TEST(test_084);