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lib/xandra/prepared.ex

defmodule Xandra.Prepared do
@moduledoc """
A data structure used to internally represent prepared queries.
"""
defstruct [:statement, :values, :id, :bound_columns, :result_columns]
@opaque t :: %__MODULE__{
statement: Xandra.statement,
values: Xandra.values | nil,
id: binary | nil,
bound_columns: list | nil,
result_columns: list | nil,
}
@doc false
def rewrite_named_params_to_positional(%__MODULE__{} = prepared, params)
when is_map(params) do
Enum.map(prepared.bound_columns, fn {_keyspace, _table, name, _type} ->
case Map.fetch(params, name) do
{:ok, value} ->
value
:error ->
raise ArgumentError,
"missing named parameter #{inspect(name)} for prepared query, " <>
"got: #{inspect(params)}"
end
end)
end
defimpl DBConnection.Query do
alias Xandra.{Frame, Protocol}
def parse(prepared, _options) do
prepared
end
def encode(prepared, values, options) when is_map(values) do
encode(prepared, @for.rewrite_named_params_to_positional(prepared, values), options)
end
def encode(prepared, values, options) when is_list(values) do
Frame.new(:execute)
|> Protocol.encode_request(%{prepared | values: values}, options)
|> Frame.encode(options[:compressor])
end
def decode(prepared, %Frame{} = frame, _options) do
Protocol.decode_response(frame, prepared)
end
def describe(prepared, _options) do
prepared
end
end
defimpl Inspect do
import Inspect.Algebra
def inspect(prepared, options) do
concat(["#Xandra.Prepared<", to_doc(prepared.statement, options), ">"])
end
end
end