mentat/src/query.rs
Richard Newman a5023c70cb Use Rc for TypedValue, Variable, and query Ident keywords. (#395) r=nalexander
Part 1, core: use Rc for String and Keyword.
Part 2, query: use Rc for Variable.
Part 3, sql: use Rc for args in SQLiteQueryBuilder.
Part 4, query-algebrizer: use Rc.
Part 5, db: use Rc.
Part 6, query-parser: use Rc.
Part 7, query-projector: use Rc.
Part 8, query-translator: use Rc.
Part 9, top level: use Rc.
Part 10: intern Ident and IdentOrKeyword.
2017-04-02 21:38:36 -07:00

95 lines
2.7 KiB
Rust

// Copyright 2016 Mozilla
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
// this file except in compliance with the License. You may obtain a copy of the
// License at http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.
use std::collections::HashMap;
use rusqlite;
use rusqlite::types::ToSql;
use mentat_core::{
Schema,
TypedValue,
};
use mentat_query_algebrizer::algebrize;
pub use mentat_query::{
NamespacedKeyword,
PlainSymbol,
};
use mentat_query_parser::{
parse_find_string,
};
use mentat_sql::{
SQLQuery,
};
use mentat_query_translator::{
query_to_select,
};
pub use mentat_query_projector::{
QueryResults,
};
use errors::Result;
pub type QueryExecutionResult = Result<QueryResults>;
/// Take an EDN query string, a reference to a open SQLite connection, a Mentat DB, and an optional
/// collection of input bindings (which should be keyed by `"?varname"`), and execute the query
/// immediately, blocking the current thread.
/// Returns a structure that corresponds to the kind of input query, populated with `TypedValue`
/// instances.
/// The caller is responsible for ensuring that the SQLite connection is in a transaction if
/// isolation is required.
#[allow(unused_variables)]
pub fn q_once<'sqlite, 'schema, 'query, T, U>
(sqlite: &'sqlite rusqlite::Connection,
schema: &'schema Schema,
query: &'query str,
inputs: T,
limit: U) -> QueryExecutionResult
where T: Into<Option<HashMap<String, TypedValue>>>,
U: Into<Option<u64>>
{
// TODO: validate inputs.
let parsed = parse_find_string(query)?;
let mut algebrized = algebrize(schema, parsed)?;
if algebrized.is_known_empty() {
// We don't need to do any SQL work at all.
return Ok(QueryResults::empty(&algebrized.find_spec));
}
algebrized.apply_limit(limit.into());
let select = query_to_select(algebrized);
let SQLQuery { sql, args } = select.query.to_sql_query()?;
let mut statement = sqlite.prepare(sql.as_str())?;
let rows = if args.is_empty() {
statement.query(&[])?
} else {
let refs: Vec<(&str, &ToSql)> =
args.iter()
.map(|&(ref k, ref v)| (k.as_str(), v.as_ref() as &ToSql))
.collect();
statement.query_named(refs.as_slice())?
};
select.projector
.project(rows)
.map_err(|e| e.into())
}