rusqlite/
pragma.rs

1//! Pragma helpers
2
3use std::ops::Deref;
4
5use crate::error::Error;
6use crate::ffi;
7use crate::types::{ToSql, ToSqlOutput, ValueRef};
8use crate::{Connection, DatabaseName, Result, Row};
9
10pub struct Sql {
11    buf: String,
12}
13
14impl Sql {
15    pub fn new() -> Sql {
16        Sql { buf: String::new() }
17    }
18
19    pub fn push_pragma(
20        &mut self,
21        schema_name: Option<DatabaseName<'_>>,
22        pragma_name: &str,
23    ) -> Result<()> {
24        self.push_keyword("PRAGMA")?;
25        self.push_space();
26        if let Some(schema_name) = schema_name {
27            self.push_schema_name(schema_name);
28            self.push_dot();
29        }
30        self.push_keyword(pragma_name)
31    }
32
33    pub fn push_keyword(&mut self, keyword: &str) -> Result<()> {
34        if !keyword.is_empty() && is_identifier(keyword) {
35            self.buf.push_str(keyword);
36            Ok(())
37        } else {
38            Err(Error::SqliteFailure(
39                ffi::Error::new(ffi::SQLITE_MISUSE),
40                Some(format!("Invalid keyword \"{}\"", keyword)),
41            ))
42        }
43    }
44
45    pub fn push_schema_name(&mut self, schema_name: DatabaseName<'_>) {
46        match schema_name {
47            DatabaseName::Main => self.buf.push_str("main"),
48            DatabaseName::Temp => self.buf.push_str("temp"),
49            DatabaseName::Attached(s) => self.push_identifier(s),
50        };
51    }
52
53    pub fn push_identifier(&mut self, s: &str) {
54        if is_identifier(s) {
55            self.buf.push_str(s);
56        } else {
57            self.wrap_and_escape(s, '"');
58        }
59    }
60
61    pub fn push_value(&mut self, value: &dyn ToSql) -> Result<()> {
62        let value = value.to_sql()?;
63        let value = match value {
64            ToSqlOutput::Borrowed(v) => v,
65            ToSqlOutput::Owned(ref v) => ValueRef::from(v),
66            #[cfg(feature = "blob")]
67            ToSqlOutput::ZeroBlob(_) => {
68                return Err(Error::SqliteFailure(
69                    ffi::Error::new(ffi::SQLITE_MISUSE),
70                    Some(format!("Unsupported value \"{:?}\"", value)),
71                ));
72            }
73            #[cfg(feature = "array")]
74            ToSqlOutput::Array(_) => {
75                return Err(Error::SqliteFailure(
76                    ffi::Error::new(ffi::SQLITE_MISUSE),
77                    Some(format!("Unsupported value \"{:?}\"", value)),
78                ));
79            }
80        };
81        match value {
82            ValueRef::Integer(i) => {
83                self.push_int(i);
84            }
85            ValueRef::Real(r) => {
86                self.push_real(r);
87            }
88            ValueRef::Text(s) => {
89                let s = std::str::from_utf8(s)?;
90                self.push_string_literal(s);
91            }
92            _ => {
93                return Err(Error::SqliteFailure(
94                    ffi::Error::new(ffi::SQLITE_MISUSE),
95                    Some(format!("Unsupported value \"{:?}\"", value)),
96                ));
97            }
98        };
99        Ok(())
100    }
101
102    pub fn push_string_literal(&mut self, s: &str) {
103        self.wrap_and_escape(s, '\'');
104    }
105
106    pub fn push_int(&mut self, i: i64) {
107        self.buf.push_str(&i.to_string());
108    }
109
110    pub fn push_real(&mut self, f: f64) {
111        self.buf.push_str(&f.to_string());
112    }
113
114    pub fn push_space(&mut self) {
115        self.buf.push(' ');
116    }
117
118    pub fn push_dot(&mut self) {
119        self.buf.push('.');
120    }
121
122    pub fn push_equal_sign(&mut self) {
123        self.buf.push('=');
124    }
125
126    pub fn open_brace(&mut self) {
127        self.buf.push('(');
128    }
129
130    pub fn close_brace(&mut self) {
131        self.buf.push(')');
132    }
133
134    pub fn as_str(&self) -> &str {
135        &self.buf
136    }
137
138    fn wrap_and_escape(&mut self, s: &str, quote: char) {
139        self.buf.push(quote);
140        let chars = s.chars();
141        for ch in chars {
142            // escape `quote` by doubling it
143            if ch == quote {
144                self.buf.push(ch);
145            }
146            self.buf.push(ch)
147        }
148        self.buf.push(quote);
149    }
150}
151
152impl Deref for Sql {
153    type Target = str;
154
155    fn deref(&self) -> &str {
156        self.as_str()
157    }
158}
159
160impl Connection {
161    /// Query the current value of `pragma_name`.
162    ///
163    /// Some pragmas will return multiple rows/values which cannot be retrieved
164    /// with this method.
165    ///
166    /// Prefer [PRAGMA function](https://sqlite.org/pragma.html#pragfunc) introduced in SQLite 3.20:
167    /// `SELECT user_version FROM pragma_user_version;`
168    pub fn pragma_query_value<T, F>(
169        &self,
170        schema_name: Option<DatabaseName<'_>>,
171        pragma_name: &str,
172        f: F,
173    ) -> Result<T>
174    where
175        F: FnOnce(&Row<'_>) -> Result<T>,
176    {
177        let mut query = Sql::new();
178        query.push_pragma(schema_name, pragma_name)?;
179        self.query_row(&query, [], f)
180    }
181
182    /// Query the current rows/values of `pragma_name`.
183    ///
184    /// Prefer [PRAGMA function](https://sqlite.org/pragma.html#pragfunc) introduced in SQLite 3.20:
185    /// `SELECT * FROM pragma_collation_list;`
186    pub fn pragma_query<F>(
187        &self,
188        schema_name: Option<DatabaseName<'_>>,
189        pragma_name: &str,
190        mut f: F,
191    ) -> Result<()>
192    where
193        F: FnMut(&Row<'_>) -> Result<()>,
194    {
195        let mut query = Sql::new();
196        query.push_pragma(schema_name, pragma_name)?;
197        let mut stmt = self.prepare(&query)?;
198        let mut rows = stmt.query([])?;
199        while let Some(result_row) = rows.next()? {
200            let row = result_row;
201            f(&row)?;
202        }
203        Ok(())
204    }
205
206    /// Query the current value(s) of `pragma_name` associated to
207    /// `pragma_value`.
208    ///
209    /// This method can be used with query-only pragmas which need an argument
210    /// (e.g. `table_info('one_tbl')`) or pragmas which returns value(s)
211    /// (e.g. `integrity_check`).
212    ///
213    /// Prefer [PRAGMA function](https://sqlite.org/pragma.html#pragfunc) introduced in SQLite 3.20:
214    /// `SELECT * FROM pragma_table_info(?);`
215    pub fn pragma<F>(
216        &self,
217        schema_name: Option<DatabaseName<'_>>,
218        pragma_name: &str,
219        pragma_value: &dyn ToSql,
220        mut f: F,
221    ) -> Result<()>
222    where
223        F: FnMut(&Row<'_>) -> Result<()>,
224    {
225        let mut sql = Sql::new();
226        sql.push_pragma(schema_name, pragma_name)?;
227        // The argument may be either in parentheses
228        // or it may be separated from the pragma name by an equal sign.
229        // The two syntaxes yield identical results.
230        sql.open_brace();
231        sql.push_value(pragma_value)?;
232        sql.close_brace();
233        let mut stmt = self.prepare(&sql)?;
234        let mut rows = stmt.query([])?;
235        while let Some(result_row) = rows.next()? {
236            let row = result_row;
237            f(&row)?;
238        }
239        Ok(())
240    }
241
242    /// Set a new value to `pragma_name`.
243    ///
244    /// Some pragmas will return the updated value which cannot be retrieved
245    /// with this method.
246    pub fn pragma_update(
247        &self,
248        schema_name: Option<DatabaseName<'_>>,
249        pragma_name: &str,
250        pragma_value: &dyn ToSql,
251    ) -> Result<()> {
252        let mut sql = Sql::new();
253        sql.push_pragma(schema_name, pragma_name)?;
254        // The argument may be either in parentheses
255        // or it may be separated from the pragma name by an equal sign.
256        // The two syntaxes yield identical results.
257        sql.push_equal_sign();
258        sql.push_value(pragma_value)?;
259        self.execute_batch(&sql)
260    }
261
262    /// Set a new value to `pragma_name` and return the updated value.
263    ///
264    /// Only few pragmas automatically return the updated value.
265    pub fn pragma_update_and_check<F, T>(
266        &self,
267        schema_name: Option<DatabaseName<'_>>,
268        pragma_name: &str,
269        pragma_value: &dyn ToSql,
270        f: F,
271    ) -> Result<T>
272    where
273        F: FnOnce(&Row<'_>) -> Result<T>,
274    {
275        let mut sql = Sql::new();
276        sql.push_pragma(schema_name, pragma_name)?;
277        // The argument may be either in parentheses
278        // or it may be separated from the pragma name by an equal sign.
279        // The two syntaxes yield identical results.
280        sql.push_equal_sign();
281        sql.push_value(pragma_value)?;
282        self.query_row(&sql, [], f)
283    }
284}
285
286fn is_identifier(s: &str) -> bool {
287    let chars = s.char_indices();
288    for (i, ch) in chars {
289        if i == 0 {
290            if !is_identifier_start(ch) {
291                return false;
292            }
293        } else if !is_identifier_continue(ch) {
294            return false;
295        }
296    }
297    true
298}
299
300fn is_identifier_start(c: char) -> bool {
301    (c >= 'A' && c <= 'Z') || c == '_' || (c >= 'a' && c <= 'z') || c > '\x7F'
302}
303
304fn is_identifier_continue(c: char) -> bool {
305    c == '$'
306        || (c >= '0' && c <= '9')
307        || (c >= 'A' && c <= 'Z')
308        || c == '_'
309        || (c >= 'a' && c <= 'z')
310        || c > '\x7F'
311}
312
313#[cfg(test)]
314mod test {
315    use super::Sql;
316    use crate::pragma;
317    use crate::{Connection, DatabaseName, Result};
318
319    #[test]
320    fn pragma_query_value() -> Result<()> {
321        let db = Connection::open_in_memory()?;
322        let user_version: i32 = db.pragma_query_value(None, "user_version", |row| row.get(0))?;
323        assert_eq!(0, user_version);
324        Ok(())
325    }
326
327    #[test]
328    #[cfg(feature = "modern_sqlite")]
329    fn pragma_func_query_value() -> Result<()> {
330        let db = Connection::open_in_memory()?;
331        let user_version: i32 =
332            db.query_row("SELECT user_version FROM pragma_user_version", [], |row| {
333                row.get(0)
334            })?;
335        assert_eq!(0, user_version);
336        Ok(())
337    }
338
339    #[test]
340    fn pragma_query_no_schema() -> Result<()> {
341        let db = Connection::open_in_memory()?;
342        let mut user_version = -1;
343        db.pragma_query(None, "user_version", |row| {
344            user_version = row.get(0)?;
345            Ok(())
346        })?;
347        assert_eq!(0, user_version);
348        Ok(())
349    }
350
351    #[test]
352    fn pragma_query_with_schema() -> Result<()> {
353        let db = Connection::open_in_memory()?;
354        let mut user_version = -1;
355        db.pragma_query(Some(DatabaseName::Main), "user_version", |row| {
356            user_version = row.get(0)?;
357            Ok(())
358        })?;
359        assert_eq!(0, user_version);
360        Ok(())
361    }
362
363    #[test]
364    fn pragma() -> Result<()> {
365        let db = Connection::open_in_memory()?;
366        let mut columns = Vec::new();
367        db.pragma(None, "table_info", &"sqlite_master", |row| {
368            let column: String = row.get(1)?;
369            columns.push(column);
370            Ok(())
371        })?;
372        assert_eq!(5, columns.len());
373        Ok(())
374    }
375
376    #[test]
377    #[cfg(feature = "modern_sqlite")]
378    fn pragma_func() -> Result<()> {
379        let db = Connection::open_in_memory()?;
380        let mut table_info = db.prepare("SELECT * FROM pragma_table_info(?)")?;
381        let mut columns = Vec::new();
382        let mut rows = table_info.query(&["sqlite_master"])?;
383
384        while let Some(row) = rows.next()? {
385            let row = row;
386            let column: String = row.get(1)?;
387            columns.push(column);
388        }
389        assert_eq!(5, columns.len());
390        Ok(())
391    }
392
393    #[test]
394    fn pragma_update() -> Result<()> {
395        let db = Connection::open_in_memory()?;
396        db.pragma_update(None, "user_version", &1)
397    }
398
399    #[test]
400    fn pragma_update_and_check() -> Result<()> {
401        let db = Connection::open_in_memory()?;
402        let journal_mode: String =
403            db.pragma_update_and_check(None, "journal_mode", &"OFF", |row| row.get(0))?;
404        assert_eq!("off", &journal_mode);
405        Ok(())
406    }
407
408    #[test]
409    fn is_identifier() {
410        assert!(pragma::is_identifier("full"));
411        assert!(pragma::is_identifier("r2d2"));
412        assert!(!pragma::is_identifier("sp ce"));
413        assert!(!pragma::is_identifier("semi;colon"));
414    }
415
416    #[test]
417    fn double_quote() {
418        let mut sql = Sql::new();
419        sql.push_schema_name(DatabaseName::Attached(r#"schema";--"#));
420        assert_eq!(r#""schema"";--""#, sql.as_str());
421    }
422
423    #[test]
424    fn wrap_and_escape() {
425        let mut sql = Sql::new();
426        sql.push_string_literal("value'; --");
427        assert_eq!("'value''; --'", sql.as_str());
428    }
429
430    #[test]
431    fn locking_mode() -> Result<()> {
432        let db = Connection::open_in_memory()?;
433        let r = db.pragma_update(None, "locking_mode", &"exclusive");
434        if cfg!(feature = "extra_check") {
435            r.unwrap_err();
436        } else {
437            r?;
438        }
439        Ok(())
440    }
441}
rusqlite/pragma.rs

rusqlite/
pragma.rs
