From f890995202ddbea7e162a175f01741866b02e10f Mon Sep 17 00:00:00 2001 From: Richard Newman Date: Thu, 16 Feb 2017 15:07:52 -0800 Subject: [PATCH] Add a rudimentary SQL builder, based on parts of Diesel. (#273) r=nalexander https://github.com/diesel-rs/diesel/ --- Cargo.toml | 3 ++ sql/Cargo.toml | 3 ++ sql/README.md | 7 +++++ sql/src/lib.rs | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 92 insertions(+) create mode 100644 sql/Cargo.toml create mode 100644 sql/README.md create mode 100644 sql/src/lib.rs diff --git a/Cargo.toml b/Cargo.toml index 6cbe021a..a141feca 100644 --- a/Cargo.toml +++ b/Cargo.toml @@ -35,6 +35,9 @@ path = "parser-utils" [dependencies.mentat_core] path = "core" +[dependencies.mentat_sql] +path = "sql" + [dependencies.mentat_db] path = "db" diff --git a/sql/Cargo.toml b/sql/Cargo.toml new file mode 100644 index 00000000..2857ab07 --- /dev/null +++ b/sql/Cargo.toml @@ -0,0 +1,3 @@ +[package] +name = "mentat_sql" +version = "0.0.1" diff --git a/sql/README.md b/sql/README.md new file mode 100644 index 00000000..4de40a91 --- /dev/null +++ b/sql/README.md @@ -0,0 +1,7 @@ +This is a tiny SQL query builder. + +The majority of this code was distilled from QueryBuilder in Diesel: + +https://github.com/diesel-rs/diesel/ + +used under the Apache 2.0 license. diff --git a/sql/src/lib.rs b/sql/src/lib.rs new file mode 100644 index 00000000..670de167 --- /dev/null +++ b/sql/src/lib.rs @@ -0,0 +1,79 @@ +// 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::error::Error; + +pub type BuildQueryError = Box; +pub type BuildQueryResult = Result<(), BuildQueryError>; + +/// Gratefully based on Diesel's QueryBuilder trait: +/// https://github.com/diesel-rs/diesel/blob/4885f61b8205f7f3c2cfa03837ed6714831abe6b/diesel/src/query_builder/mod.rs#L56 +pub trait QueryBuilder { + fn push_sql(&mut self, sql: &str); + fn push_identifier(&mut self, identifier: &str) -> BuildQueryResult; + fn push_bind_param(&mut self); + fn finish(self) -> String; +} + +pub trait QueryFragment { + fn push_sql(&self, out: &mut QueryBuilder) -> BuildQueryResult; +} + +impl QueryFragment for Box { + fn push_sql(&self, out: &mut QueryBuilder) -> BuildQueryResult { + QueryFragment::push_sql(&**self, out) + } +} + +impl<'a> QueryFragment for &'a QueryFragment { + fn push_sql(&self, out: &mut QueryBuilder) -> BuildQueryResult { + QueryFragment::push_sql(&**self, out) + } +} + +impl QueryFragment for () { + fn push_sql(&self, _out: &mut QueryBuilder) -> BuildQueryResult { + Ok(()) + } +} + +/// A QueryBuilder that implements SQLite's specific escaping rules. +pub struct SQLiteQueryBuilder { + pub sql: String, +} + +impl SQLiteQueryBuilder { + pub fn new() -> Self { + SQLiteQueryBuilder { + sql: String::new(), + } + } +} + +impl QueryBuilder for SQLiteQueryBuilder { + fn push_sql(&mut self, sql: &str) { + self.sql.push_str(sql); + } + + fn push_identifier(&mut self, identifier: &str) -> BuildQueryResult { + self.push_sql("`"); + self.push_sql(&identifier.replace("`", "``")); + self.push_sql("`"); + Ok(()) + } + + fn push_bind_param(&mut self) { + self.push_sql("?"); + } + + fn finish(self) -> String { + self.sql + } +}