before this change, we rely on the default-generated fmt::formatter
created from operator<<, but fmt v10 dropped the default-generated
formatter.
in this change, we define formatters for
* raw_value
* raw_value_view
`raw_value_view` 's operator<< is still being used by the generic
homebrew printer for vector<>, so it is preserved.
`raw_value` 's operator<< is still being used by the generic
homebrew printer for optional<>, so it's preserved as well.
Refs #13245
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
The CQL binary protocol introduced "unset" values in version 4
of the protocol. Unset values can be bound to variables, which
cause certain CQL fragments to be skipped. For example, the
fragment `SET a = :var` will not change the value of `a` if `:var`
is bound to an unset value.
Unsets, however, are very limited in where they can appear. They
can only appear at the top-level of an expression, and any computation
done with them is invalid. For example, `SET list_column = [3, :var]`
is invalid if `:var` is bound to unset.
This causes the code to be littered with checks for unset, and there
are plenty of tests dedicated to catching unsets. However, a simpler
way is possible - prevent the infiltration of unsets at the point of
entry (when evaluating a bind variable expression), and introduce
guards to check for the few cases where unsets are allowed.
This is what this long patch does. It performs the following:
(general)
1. unset is removed from the possible values of cql3::raw_value and
cql3::raw_value_view.
(external->cql3)
2. query_options is fortified with a vector of booleans,
unset_bind_variable_vector, where each boolean corresponds to a bind
variable index and is true when it is unset.
3. To avoid churn, two compatiblity structs are introduced:
cql3::raw_value{,_view}_vector_with_unset, which can be constructed
from a std::vector<raw_value{,_view/}>, which is what most callers
have. They can also be constructed with explicit unset vectors, for
the few cases they are needed.
(cql3->variables)
4. query_options::get_value_at() now throws if the requested bind variable
is unset. This replaces all the throwing checks in expression evaluation
and statement execution, which are removed.
5. A new query_options::is_unset() is added for the users that can tolerate
unset; though it is not used directly.
6. A new cql3::unset_operation_guard class guards against unsets. It accepts
an expression, and can be queried whether an unset is present. Two
conditions are checked: the expression must be a singleton bind
variable, and at runtime it must be bound to an unset value.
7. The modification_statement operations are split into two, via two
new subclasses of cql3::operation. cql3::operation_no_unset_support
ignores unsets completely. cql3::operation_skip_if_unset checks if
an operand is unset (luckily all operations have at most one operand that
tolerates unset) and applies unset_operation_guard to it.
8. The various sites that accept expressions or operations are modified
to check for should_skip_operation(). This are the loops around
operations in update_statement and delete_statement, and the checks
for unset in attributes (LIMIT and PER PARTITION LIMIT)
(tests)
9. Many unset tests are removed. It's now impossible to enter an
unset value into the expression evaluation machinery (there's
just no unset value), so it's impossible to test for it.
10. Other unset tests now have to be invoked via bind variables,
since there's no way to create an unset cql3::expr::constant.
11. Many tests have their exception message match strings relaxed.
Since unsets are now checked very early, we don't know the context
where they happen. It would be possible to reintroduce it (by adding
a format string parameter to cql3::unset_operation_guard), but it
seems not to be worth the effort. Usage of unsets is rare, and it is
explicit (at least with the Python driver, an unset cannot be
introduced by ommission).
I tried as an alternative to wrap cql3::raw_value{,_view} (that doesn't
recognize unsets) with cql3::maybe_unset_value (that does), but that
caused huge amounts of churn, so I abandoned that in favor of the
current approach.
Closes#12517
It's possible to print raw_value_view,
but not raw_value. It would be useful
to be able to print both.
Implement printing raw_value
by creating raw_value_view from it
and printing the view.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
This is useful for implementing operator==() for expressions, which in
turn require comparing constants, which contain raw_values.
Note that this is not CQL comparison (that would be implemented
in cql3::expr::evaluate() and would return a CQL boolean, not a C++
boolean, but a traditional C++ value comparison.
Commit e739f2b779 ("cql3: expr: make evaluate() return a
cql3::raw_value rather than an expr::constant") introduced
raw_value::view() as a synonym to raw_value::to_view() to reduce
churn. To fix this duplication, we now remove raw_value::to_view().
raw_value::to_view() was picked for removal because is has fewer
call sites, reducing churn again.
Closes#10819
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
When unset_value is passed to make_temporary it gets converted to null_value.
This looks like a mistake, it should be just unset_value.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
This reverts commit e9343fd382, reversing
changes made to 27138b215b. It causes a
regression in v2 serialization_format support:
collection_serialization_with_protocol_v2_test fails with: marshaling error: read_simple_bytes - not enough bytes (requested 1627390306, got 3)
Fixes#9360
When unset_value is passed to make_temporary it gets converted to null_value.
This looks like a mistake, it should be just unset_value.
Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com>
As a part of the effort of removing big, contiguous buffers from the codebase,
cql3::raw_value should be made fragmented. Unfortunately the change involves
some nontrivial work, because raw_value must be viewable with raw_value_view,
and raw_value_view must accomodate both raw_value (that's where we store
values in prepared queries) and fragmented_temporary_buffer::view
(because that's the type of values coming from the wire).
This patch makes raw_value fragmented, by changing the backing type from
bytes to managed_bytes. raw_value_view is modified accordingly by changing
the backing type from fragmented_temporary_buffer::view to a variant of
fragmented_temporary_buffer::view and managed_bytes_view.
We have prepared the users of raw_value{_view} for this change in preceding
commits.
When a value_view needs to store a temporarily instantiated object,
it can use the new variant field. The temporary value will live
only as long as the view itself.
