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