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//! Pragma helpers
use std::ops::Deref;
use crate::error::Error;
use crate::ffi;
use crate::types::{ToSql, ToSqlOutput, ValueRef};
use crate::{Connection, DatabaseName, Result, Row};
pub struct Sql {
buf: String,
}
impl Sql {
pub fn new() -> Sql {
Sql { buf: String::new() }
}
pub fn push_pragma(
&mut self,
schema_name: Option<DatabaseName<'_>>,
pragma_name: &str,
) -> Result<()> {
self.push_keyword("PRAGMA")?;
self.push_space();
if let Some(schema_name) = schema_name {
self.push_schema_name(schema_name);
self.push_dot();
}
self.push_keyword(pragma_name)
}
pub fn push_keyword(&mut self, keyword: &str) -> Result<()> {
if !keyword.is_empty() && is_identifier(keyword) {
self.buf.push_str(keyword);
Ok(())
} else {
Err(Error::SqliteFailure(
ffi::Error::new(ffi::SQLITE_MISUSE),
Some(format!("Invalid keyword \"{keyword}\"")),
))
}
}
pub fn push_schema_name(&mut self, schema_name: DatabaseName<'_>) {
match schema_name {
DatabaseName::Main => self.buf.push_str("main"),
DatabaseName::Temp => self.buf.push_str("temp"),
DatabaseName::Attached(s) => self.push_identifier(s),
};
}
pub fn push_identifier(&mut self, s: &str) {
if is_identifier(s) {
self.buf.push_str(s);
} else {
self.wrap_and_escape(s, '"');
}
}
pub fn push_value(&mut self, value: &dyn ToSql) -> Result<()> {
let value = value.to_sql()?;
let value = match value {
ToSqlOutput::Borrowed(v) => v,
ToSqlOutput::Owned(ref v) => ValueRef::from(v),
#[cfg(feature = "blob")]
ToSqlOutput::ZeroBlob(_) => {
return Err(Error::SqliteFailure(
ffi::Error::new(ffi::SQLITE_MISUSE),
Some(format!("Unsupported value \"{value:?}\"")),
));
}
#[cfg(feature = "functions")]
ToSqlOutput::Arg(_) => {
return Err(Error::SqliteFailure(
ffi::Error::new(ffi::SQLITE_MISUSE),
Some(format!("Unsupported value \"{value:?}\"")),
));
}
#[cfg(feature = "array")]
ToSqlOutput::Array(_) => {
return Err(Error::SqliteFailure(
ffi::Error::new(ffi::SQLITE_MISUSE),
Some(format!("Unsupported value \"{value:?}\"")),
));
}
};
match value {
ValueRef::Integer(i) => {
self.push_int(i);
}
ValueRef::Real(r) => {
self.push_real(r);
}
ValueRef::Text(s) => {
let s = std::str::from_utf8(s)?;
self.push_string_literal(s);
}
_ => {
return Err(Error::SqliteFailure(
ffi::Error::new(ffi::SQLITE_MISUSE),
Some(format!("Unsupported value \"{value:?}\"")),
));
}
};
Ok(())
}
pub fn push_string_literal(&mut self, s: &str) {
self.wrap_and_escape(s, '\'');
}
pub fn push_int(&mut self, i: i64) {
self.buf.push_str(&i.to_string());
}
pub fn push_real(&mut self, f: f64) {
self.buf.push_str(&f.to_string());
}
pub fn push_space(&mut self) {
self.buf.push(' ');
}
pub fn push_dot(&mut self) {
self.buf.push('.');
}
pub fn push_equal_sign(&mut self) {
self.buf.push('=');
}
pub fn open_brace(&mut self) {
self.buf.push('(');
}
pub fn close_brace(&mut self) {
self.buf.push(')');
}
pub fn as_str(&self) -> &str {
&self.buf
}
fn wrap_and_escape(&mut self, s: &str, quote: char) {
self.buf.push(quote);
let chars = s.chars();
for ch in chars {
// escape `quote` by doubling it
if ch == quote {
self.buf.push(ch);
}
self.buf.push(ch);
}
self.buf.push(quote);
}
}
impl Deref for Sql {
type Target = str;
fn deref(&self) -> &str {
self.as_str()
}
}
impl Connection {
/// Query the current value of `pragma_name`.
///
/// Some pragmas will return multiple rows/values which cannot be retrieved
/// with this method.
///
/// `SELECT user_version FROM pragma_user_version;`
pub fn pragma_query_value<T, F>(
&self,
schema_name: Option<DatabaseName<'_>>,
pragma_name: &str,
f: F,
) -> Result<T>
where
F: FnOnce(&Row<'_>) -> Result<T>,
{
let mut query = Sql::new();
query.push_pragma(schema_name, pragma_name)?;
self.query_row(&query, [], f)
}
/// Query the current rows/values of `pragma_name`.
///
/// `SELECT * FROM pragma_collation_list;`
pub fn pragma_query<F>(
&self,
schema_name: Option<DatabaseName<'_>>,
pragma_name: &str,
mut f: F,
) -> Result<()>
where
F: FnMut(&Row<'_>) -> Result<()>,
{
let mut query = Sql::new();
query.push_pragma(schema_name, pragma_name)?;
let mut stmt = self.prepare(&query)?;
let mut rows = stmt.query([])?;
while let Some(result_row) = rows.next()? {
let row = result_row;
f(row)?;
}
Ok(())
}
/// Query the current value(s) of `pragma_name` associated to
/// `pragma_value`.
///
/// This method can be used with query-only pragmas which need an argument
/// (e.g. `table_info('one_tbl')`) or pragmas which returns value(s)
/// (e.g. `integrity_check`).
///
/// `SELECT * FROM pragma_table_info(?1);`
pub fn pragma<F, V>(
&self,
schema_name: Option<DatabaseName<'_>>,
pragma_name: &str,
pragma_value: V,
mut f: F,
) -> Result<()>
where
F: FnMut(&Row<'_>) -> Result<()>,
V: ToSql,
{
let mut sql = Sql::new();
sql.push_pragma(schema_name, pragma_name)?;
// The argument may be either in parentheses
// or it may be separated from the pragma name by an equal sign.
// The two syntaxes yield identical results.
sql.open_brace();
sql.push_value(&pragma_value)?;
sql.close_brace();
let mut stmt = self.prepare(&sql)?;
let mut rows = stmt.query([])?;
while let Some(result_row) = rows.next()? {
let row = result_row;
f(row)?;
}
Ok(())
}
/// Set a new value to `pragma_name`.
///
/// Some pragmas will return the updated value which cannot be retrieved
/// with this method.
pub fn pragma_update<V>(
&self,
schema_name: Option<DatabaseName<'_>>,
pragma_name: &str,
pragma_value: V,
) -> Result<()>
where
V: ToSql,
{
let mut sql = Sql::new();
sql.push_pragma(schema_name, pragma_name)?;
// The argument may be either in parentheses
// or it may be separated from the pragma name by an equal sign.
// The two syntaxes yield identical results.
sql.push_equal_sign();
sql.push_value(&pragma_value)?;
self.execute_batch(&sql)
}
/// Set a new value to `pragma_name` and return the updated value.
///
/// Only few pragmas automatically return the updated value.
pub fn pragma_update_and_check<F, T, V>(
&self,
schema_name: Option<DatabaseName<'_>>,
pragma_name: &str,
pragma_value: V,
f: F,
) -> Result<T>
where
F: FnOnce(&Row<'_>) -> Result<T>,
V: ToSql,
{
let mut sql = Sql::new();
sql.push_pragma(schema_name, pragma_name)?;
// The argument may be either in parentheses
// or it may be separated from the pragma name by an equal sign.
// The two syntaxes yield identical results.
sql.push_equal_sign();
sql.push_value(&pragma_value)?;
self.query_row(&sql, [], f)
}
}
fn is_identifier(s: &str) -> bool {
let chars = s.char_indices();
for (i, ch) in chars {
if i == 0 {
if !is_identifier_start(ch) {
return false;
}
} else if !is_identifier_continue(ch) {
return false;
}
}
true
}
fn is_identifier_start(c: char) -> bool {
c.is_ascii_uppercase() || c == '_' || c.is_ascii_lowercase() || c > '\x7F'
}
fn is_identifier_continue(c: char) -> bool {
c == '$'
|| c.is_ascii_digit()
|| c.is_ascii_uppercase()
|| c == '_'
|| c.is_ascii_lowercase()
|| c > '\x7F'
}
#[cfg(test)]
mod test {
use super::Sql;
use crate::pragma;
use crate::{Connection, DatabaseName, Result};
#[test]
fn pragma_query_value() -> Result<()> {
let db = Connection::open_in_memory()?;
let user_version: i32 = db.pragma_query_value(None, "user_version", |row| row.get(0))?;
assert_eq!(0, user_version);
Ok(())
}
#[test]
#[cfg(feature = "modern_sqlite")]
fn pragma_func_query_value() -> Result<()> {
let db = Connection::open_in_memory()?;
let user_version: i32 = db.one_column("SELECT user_version FROM pragma_user_version")?;
assert_eq!(0, user_version);
Ok(())
}
#[test]
fn pragma_query_no_schema() -> Result<()> {
let db = Connection::open_in_memory()?;
let mut user_version = -1;
db.pragma_query(None, "user_version", |row| {
user_version = row.get(0)?;
Ok(())
})?;
assert_eq!(0, user_version);
Ok(())
}
#[test]
fn pragma_query_with_schema() -> Result<()> {
let db = Connection::open_in_memory()?;
let mut user_version = -1;
db.pragma_query(Some(DatabaseName::Main), "user_version", |row| {
user_version = row.get(0)?;
Ok(())
})?;
assert_eq!(0, user_version);
Ok(())
}
#[test]
fn pragma() -> Result<()> {
let db = Connection::open_in_memory()?;
let mut columns = Vec::new();
db.pragma(None, "table_info", "sqlite_master", |row| {
let column: String = row.get(1)?;
columns.push(column);
Ok(())
})?;
assert_eq!(5, columns.len());
Ok(())
}
#[test]
#[cfg(feature = "modern_sqlite")]
fn pragma_func() -> Result<()> {
let db = Connection::open_in_memory()?;
let mut table_info = db.prepare("SELECT * FROM pragma_table_info(?1)")?;
let mut columns = Vec::new();
let mut rows = table_info.query(["sqlite_master"])?;
while let Some(row) = rows.next()? {
let column: String = row.get(1)?;
columns.push(column);
}
assert_eq!(5, columns.len());
Ok(())
}
#[test]
fn pragma_update() -> Result<()> {
let db = Connection::open_in_memory()?;
db.pragma_update(None, "user_version", 1)
}
#[test]
fn pragma_update_and_check() -> Result<()> {
let db = Connection::open_in_memory()?;
let journal_mode: String =
db.pragma_update_and_check(None, "journal_mode", "OFF", |row| row.get(0))?;
assert!(
journal_mode == "off" || journal_mode == "memory",
"mode: {journal_mode:?}"
);
// Sanity checks to ensure the move to a generic `ToSql` wasn't breaking
let mode =
db.pragma_update_and_check(None, "journal_mode", "OFF", |row| row.get::<_, String>(0))?;
assert!(mode == "off" || mode == "memory", "mode: {mode:?}");
let param: &dyn crate::ToSql = &"OFF";
let mode =
db.pragma_update_and_check(None, "journal_mode", param, |row| row.get::<_, String>(0))?;
assert!(mode == "off" || mode == "memory", "mode: {mode:?}");
Ok(())
}
#[test]
fn is_identifier() {
assert!(pragma::is_identifier("full"));
assert!(pragma::is_identifier("r2d2"));
assert!(!pragma::is_identifier("sp ce"));
assert!(!pragma::is_identifier("semi;colon"));
}
#[test]
fn double_quote() {
let mut sql = Sql::new();
sql.push_schema_name(DatabaseName::Attached(r#"schema";--"#));
assert_eq!(r#""schema"";--""#, sql.as_str());
}
#[test]
fn wrap_and_escape() {
let mut sql = Sql::new();
sql.push_string_literal("value'; --");
assert_eq!("'value''; --'", sql.as_str());
}
#[test]
fn locking_mode() -> Result<()> {
let db = Connection::open_in_memory()?;
let r = db.pragma_update(None, "locking_mode", "exclusive");
if cfg!(feature = "extra_check") {
r.unwrap_err();
} else {
r?;
}
Ok(())
}
}