nomicon/development/libs/barrel/src/backend/sqlite3.rs

//! Sqlite3 implementation of a generator

use super::SqlGenerator;
use crate::types::{BaseType, Type};

/// A simple macro that will generate a schema prefix if it exists
macro_rules! prefix {
    ($schema:expr) => {
        $schema
            .map(|s| format!("\"{}\".", s))
            .unwrap_or_else(|| String::new())
    };
}

/// We call this struct Sqlite instead of Sqlite3 because we hope not
/// to have to break the API further down the road
pub struct Sqlite;
impl SqlGenerator for Sqlite {
    fn create_table(name: &str, schema: Option<&str>) -> String {
        format!("CREATE TABLE {}\"{}\"", prefix!(schema), name)
    }

    fn create_table_if_not_exists(name: &str, schema: Option<&str>) -> String {
        format!("CREATE TABLE IF NOT EXISTS {}\"{}\"", prefix!(schema), name)
    }

    fn drop_table(name: &str, schema: Option<&str>) -> String {
        format!("DROP TABLE {}\"{}\"", prefix!(schema), name)
    }

    fn drop_table_if_exists(name: &str, schema: Option<&str>) -> String {
        format!("DROP TABLE IF EXISTS {}\"{}\"", prefix!(schema), name)
    }

    fn rename_table(old: &str, new: &str, schema: Option<&str>) -> String {
        let schema = prefix!(schema);
        format!("ALTER TABLE {}\"{}\" RENAME TO \"{}\"", schema, old, new)
    }

    fn alter_table(name: &str, schema: Option<&str>) -> String {
        format!("ALTER TABLE {}\"{}\"", prefix!(schema), name)
    }

    fn add_column(ex: bool, _: Option<&str>, name: &str, tt: &Type) -> String {
        let bt: BaseType = tt.get_inner();
        use self::BaseType::*;

        #[cfg_attr(rustfmt, rustfmt_skip)] /* This shouldn't be formatted. It's too long */
        format!(
            // SQL base - default - nullable - unique
            "{}{}{}{}{}",
            match bt {
                Text => format!("{}\"{}\" {}", Sqlite::prefix(ex), name, Sqlite::print_type(bt)),
                Varchar(_) => format!("{}\"{}\" {}", Sqlite::prefix(ex), name, Sqlite::print_type(bt)),
                Primary => format!("{}\"{}\" {}", Sqlite::prefix(ex), name, Sqlite::print_type(bt)),
                Integer => format!("{}\"{}\" {}", Sqlite::prefix(ex), name, Sqlite::print_type(bt)),
                Float => format!("{}\"{}\" {}", Sqlite::prefix(ex), name, Sqlite::print_type(bt)),
                Double => format!("{}\"{}\" {}", Sqlite::prefix(ex), name, Sqlite::print_type(bt)),
                UUID => panic!("`UUID` not supported by Sqlite3. Use `Text` instead!"),
                Json => panic!("`Json` not supported by Sqlite3. Use `Text` instead!"),
                Boolean => format!("{}\"{}\" {}", Sqlite::prefix(ex), name, Sqlite::print_type(bt)),
                Date => format!("{}\"{}\" {}", Sqlite::prefix(ex), name, Sqlite::print_type(bt)),
                Binary => format!("{}\"{}\" {}", Sqlite::prefix(ex), name, Sqlite::print_type(bt)),
                Foreign(_, _, _) => format!("{}\"{}\" {}", Sqlite::prefix(ex), name, Sqlite::print_type(bt)),
                Custom(_) => format!("{}\"{}\" {}", Sqlite::prefix(ex), name, Sqlite::print_type(bt)),
                Array(it) => format!("{}\"{}\" {}", Sqlite::prefix(ex), name, Sqlite::print_type(Array(Box::new(*it)))),
                Index(_) => unreachable!(), // Indices are handled via custom builders
            },
            match tt.primary {
                true => " PRIMARY KEY",
                false => "",
            },
            match (&tt.default).as_ref() {
                Some(ref m) => format!(" DEFAULT '{}'", m),
                _ => format!(""),
            },
            match tt.nullable {
                true => "",
                false => " NOT NULL",
            },
            match tt.unique {
                true => " UNIQUE",
                false => "",
            }
        )
    }

    /// Create a multi-column index
    fn create_index(table: &str, schema: Option<&str>, name: &str, _type: &Type) -> String {
        format!(
            "CREATE {} INDEX {}\"{}\" ON \"{}\" ({});",
            match _type.unique {
                true => "UNIQUE",
                false => "",
            },
            prefix!(schema),
            name,
            table,
            match _type.inner {
                BaseType::Index(ref cols) => cols
                    .iter()
                    .map(|col| format!("\"{}\"", col))
                    .collect::<Vec<_>>()
                    .join(", "),
                _ => unreachable!(),
            }
        )
    }

    /// Drop a multi-column index
    fn drop_index(name: &str) -> String {
        format!("DROP INDEX \"{}\"", name)
    }

    fn drop_column(_: &str) -> String {
        panic!("Sqlite does not support dropping columns!")
    }

    fn rename_column(_: &str, _: &str) -> String {
        panic!("Sqlite does not support renaming columns!")
    }
}

impl Sqlite {
    fn prefix(ex: bool) -> String {
        match ex {
            true => format!("ADD COLUMN "),
            false => format!(""),
        }
    }

    fn print_type(t: BaseType) -> String {
        use self::BaseType::*;
        match t {
            Text => format!("TEXT"),
            Varchar(l) => match l {
                0 => format!("VARCHAR"), // For "0" remove the limit
                _ => format!("VARCHAR({})", l),
            },
            Primary => format!("INTEGER NOT NULL PRIMARY KEY"),
            Integer => format!("INTEGER"),
            Float => format!("REAL"),
            Double => format!("DOUBLE"),
            UUID => unimplemented!(),
            Boolean => format!("BOOLEAN"),
            Date => format!("DATE"),
            Json => panic!("Json is not supported by Sqlite3"),
            Binary => format!("BINARY"),
            Foreign(_, t, refs) => format!("INTEGER REFERENCES {}({})", t, refs.0.join(",")),
            Custom(t) => format!("{}", t),
            Array(meh) => format!("{}[]", Sqlite::print_type(*meh)),
            Index(_) => unimplemented!(),
        }
    }
}