1use std::{
2 cell::RefCell,
3 ffi::{CStr, CString},
4 marker::PhantomData,
5 path::Path,
6 ptr,
7};
8
9use anyhow::{anyhow, Result};
10use libsqlite3_sys::*;
11
12pub struct Connection {
13 pub(crate) sqlite3: *mut sqlite3,
14 persistent: bool,
15 pub(crate) write: RefCell<bool>,
16 _sqlite: PhantomData<sqlite3>,
17}
18unsafe impl Send for Connection {}
19
20impl Connection {
21 pub(crate) fn open(uri: &str, persistent: bool) -> Result<Self> {
22 let mut connection = Self {
23 sqlite3: ptr::null_mut(),
24 persistent,
25 write: RefCell::new(true),
26 _sqlite: PhantomData,
27 };
28
29 let flags = SQLITE_OPEN_CREATE | SQLITE_OPEN_NOMUTEX | SQLITE_OPEN_READWRITE;
30 unsafe {
31 sqlite3_open_v2(
32 CString::new(uri)?.as_ptr(),
33 &mut connection.sqlite3,
34 flags,
35 ptr::null(),
36 );
37
38 // Turn on extended error codes
39 sqlite3_extended_result_codes(connection.sqlite3, 1);
40
41 connection.last_error()?;
42 }
43
44 Ok(connection)
45 }
46
47 /// Attempts to open the database at uri. If it fails, a shared memory db will be opened
48 /// instead.
49 pub fn open_file(uri: &str) -> Self {
50 Self::open(uri, true).unwrap_or_else(|_| Self::open_memory(Some(uri)))
51 }
52
53 pub fn open_memory(uri: Option<&str>) -> Self {
54 let in_memory_path = if let Some(uri) = uri {
55 format!("file:{}?mode=memory&cache=shared", uri)
56 } else {
57 ":memory:".to_string()
58 };
59
60 Self::open(&in_memory_path, false).expect("Could not create fallback in memory db")
61 }
62
63 pub fn persistent(&self) -> bool {
64 self.persistent
65 }
66
67 pub fn can_write(&self) -> bool {
68 *self.write.borrow()
69 }
70
71 pub fn backup_main(&self, destination: &Connection) -> Result<()> {
72 unsafe {
73 let backup = sqlite3_backup_init(
74 destination.sqlite3,
75 CString::new("main")?.as_ptr(),
76 self.sqlite3,
77 CString::new("main")?.as_ptr(),
78 );
79 sqlite3_backup_step(backup, -1);
80 sqlite3_backup_finish(backup);
81 destination.last_error()
82 }
83 }
84
85 pub fn backup_main_to(&self, destination: impl AsRef<Path>) -> Result<()> {
86 let destination = Self::open_file(destination.as_ref().to_string_lossy().as_ref());
87 self.backup_main(&destination)
88 }
89
90 pub fn sql_has_syntax_error(&self, sql: &str) -> Option<(String, usize)> {
91 let sql = CString::new(sql).unwrap();
92 let mut remaining_sql = sql.as_c_str();
93 let sql_start = remaining_sql.as_ptr();
94
95 unsafe {
96 let mut alter_table = None;
97 while {
98 let remaining_sql_str = remaining_sql.to_str().unwrap().trim();
99 let any_remaining_sql = remaining_sql_str != ";" && !remaining_sql_str.is_empty();
100 if any_remaining_sql {
101 alter_table = parse_alter_table(remaining_sql_str);
102 }
103 any_remaining_sql
104 } {
105 let mut raw_statement = ptr::null_mut::<sqlite3_stmt>();
106 let mut remaining_sql_ptr = ptr::null();
107
108 let (res, offset, message, _conn) = if let Some(table_to_alter) = alter_table {
109 // ALTER TABLE is a weird statement. When preparing the statement the table's
110 // existence is checked *before* syntax checking any other part of the statement.
111 // Therefore, we need to make sure that the table has been created before calling
112 // prepare. As we don't want to trash whatever database this is connected to, we
113 // create a new in-memory DB to test.
114
115 let temp_connection = Connection::open_memory(None);
116 //This should always succeed, if it doesn't then you really should know about it
117 temp_connection
118 .exec(&format!(
119 "CREATE TABLE {table_to_alter}(__place_holder_column_for_syntax_checking)"
120 ))
121 .unwrap()()
122 .unwrap();
123
124 sqlite3_prepare_v2(
125 temp_connection.sqlite3,
126 remaining_sql.as_ptr(),
127 -1,
128 &mut raw_statement,
129 &mut remaining_sql_ptr,
130 );
131
132 (
133 sqlite3_errcode(temp_connection.sqlite3),
134 sqlite3_error_offset(temp_connection.sqlite3),
135 sqlite3_errmsg(temp_connection.sqlite3),
136 Some(temp_connection),
137 )
138 } else {
139 sqlite3_prepare_v2(
140 self.sqlite3,
141 remaining_sql.as_ptr(),
142 -1,
143 &mut raw_statement,
144 &mut remaining_sql_ptr,
145 );
146 (
147 sqlite3_errcode(self.sqlite3),
148 sqlite3_error_offset(self.sqlite3),
149 sqlite3_errmsg(self.sqlite3),
150 None,
151 )
152 };
153
154 sqlite3_finalize(raw_statement);
155
156 if res == 1 && offset >= 0 {
157 let sub_statement_correction =
158 remaining_sql.as_ptr() as usize - sql_start as usize;
159 let err_msg =
160 String::from_utf8_lossy(CStr::from_ptr(message as *const _).to_bytes())
161 .into_owned();
162
163 return Some((err_msg, offset as usize + sub_statement_correction));
164 }
165 remaining_sql = CStr::from_ptr(remaining_sql_ptr);
166 alter_table = None;
167 }
168 }
169 None
170 }
171
172 pub(crate) fn last_error(&self) -> Result<()> {
173 unsafe {
174 let code = sqlite3_errcode(self.sqlite3);
175 const NON_ERROR_CODES: &[i32] = &[SQLITE_OK, SQLITE_ROW];
176 if NON_ERROR_CODES.contains(&code) {
177 return Ok(());
178 }
179
180 let message = sqlite3_errmsg(self.sqlite3);
181 let message = if message.is_null() {
182 None
183 } else {
184 Some(
185 String::from_utf8_lossy(CStr::from_ptr(message as *const _).to_bytes())
186 .into_owned(),
187 )
188 };
189
190 Err(anyhow!(
191 "Sqlite call failed with code {} and message: {:?}",
192 code as isize,
193 message
194 ))
195 }
196 }
197
198 pub(crate) fn with_write<T>(&self, callback: impl FnOnce(&Connection) -> T) -> T {
199 *self.write.borrow_mut() = true;
200 let result = callback(self);
201 *self.write.borrow_mut() = false;
202 result
203 }
204}
205
206fn parse_alter_table(remaining_sql_str: &str) -> Option<String> {
207 let remaining_sql_str = remaining_sql_str.to_lowercase();
208 if remaining_sql_str.starts_with("alter") {
209 if let Some(table_offset) = remaining_sql_str.find("table") {
210 let after_table_offset = table_offset + "table".len();
211 let table_to_alter = remaining_sql_str
212 .chars()
213 .skip(after_table_offset)
214 .skip_while(|c| c.is_whitespace())
215 .take_while(|c| !c.is_whitespace())
216 .collect::<String>();
217 if !table_to_alter.is_empty() {
218 return Some(table_to_alter);
219 }
220 }
221 }
222 None
223}
224
225impl Drop for Connection {
226 fn drop(&mut self) {
227 unsafe { sqlite3_close(self.sqlite3) };
228 }
229}
230
231#[cfg(test)]
232mod test {
233 use anyhow::Result;
234 use indoc::indoc;
235
236 use crate::connection::Connection;
237
238 #[test]
239 fn string_round_trips() -> Result<()> {
240 let connection = Connection::open_memory(Some("string_round_trips"));
241 connection
242 .exec(indoc! {"
243 CREATE TABLE text (
244 text TEXT
245 );"})
246 .unwrap()()
247 .unwrap();
248
249 let text = "Some test text";
250
251 connection
252 .exec_bound("INSERT INTO text (text) VALUES (?);")
253 .unwrap()(text)
254 .unwrap();
255
256 assert_eq!(
257 connection.select_row("SELECT text FROM text;").unwrap()().unwrap(),
258 Some(text.to_string())
259 );
260
261 Ok(())
262 }
263
264 #[test]
265 fn tuple_round_trips() {
266 let connection = Connection::open_memory(Some("tuple_round_trips"));
267 connection
268 .exec(indoc! {"
269 CREATE TABLE test (
270 text TEXT,
271 integer INTEGER,
272 blob BLOB
273 );"})
274 .unwrap()()
275 .unwrap();
276
277 let tuple1 = ("test".to_string(), 64, vec![0, 1, 2, 4, 8, 16, 32, 64]);
278 let tuple2 = ("test2".to_string(), 32, vec![64, 32, 16, 8, 4, 2, 1, 0]);
279
280 let mut insert = connection
281 .exec_bound::<(String, usize, Vec<u8>)>(
282 "INSERT INTO test (text, integer, blob) VALUES (?, ?, ?)",
283 )
284 .unwrap();
285
286 insert(tuple1.clone()).unwrap();
287 insert(tuple2.clone()).unwrap();
288
289 assert_eq!(
290 connection
291 .select::<(String, usize, Vec<u8>)>("SELECT * FROM test")
292 .unwrap()()
293 .unwrap(),
294 vec![tuple1, tuple2]
295 );
296 }
297
298 #[test]
299 fn bool_round_trips() {
300 let connection = Connection::open_memory(Some("bool_round_trips"));
301 connection
302 .exec(indoc! {"
303 CREATE TABLE bools (
304 t INTEGER,
305 f INTEGER
306 );"})
307 .unwrap()()
308 .unwrap();
309
310 connection
311 .exec_bound("INSERT INTO bools(t, f) VALUES (?, ?)")
312 .unwrap()((true, false))
313 .unwrap();
314
315 assert_eq!(
316 connection
317 .select_row::<(bool, bool)>("SELECT * FROM bools;")
318 .unwrap()()
319 .unwrap(),
320 Some((true, false))
321 );
322 }
323
324 #[test]
325 fn backup_works() {
326 let connection1 = Connection::open_memory(Some("backup_works"));
327 connection1
328 .exec(indoc! {"
329 CREATE TABLE blobs (
330 data BLOB
331 );"})
332 .unwrap()()
333 .unwrap();
334 let blob = vec![0, 1, 2, 4, 8, 16, 32, 64];
335 connection1
336 .exec_bound::<Vec<u8>>("INSERT INTO blobs (data) VALUES (?);")
337 .unwrap()(blob.clone())
338 .unwrap();
339
340 // Backup connection1 to connection2
341 let connection2 = Connection::open_memory(Some("backup_works_other"));
342 connection1.backup_main(&connection2).unwrap();
343
344 // Delete the added blob and verify its deleted on the other side
345 let read_blobs = connection1
346 .select::<Vec<u8>>("SELECT * FROM blobs;")
347 .unwrap()()
348 .unwrap();
349 assert_eq!(read_blobs, vec![blob]);
350 }
351
352 #[test]
353 fn multi_step_statement_works() {
354 let connection = Connection::open_memory(Some("multi_step_statement_works"));
355
356 connection
357 .exec(indoc! {"
358 CREATE TABLE test (
359 col INTEGER
360 )"})
361 .unwrap()()
362 .unwrap();
363
364 connection
365 .exec(indoc! {"
366 INSERT INTO test(col) VALUES (2)"})
367 .unwrap()()
368 .unwrap();
369
370 assert_eq!(
371 connection
372 .select_row::<usize>("SELECT * FROM test")
373 .unwrap()()
374 .unwrap(),
375 Some(2)
376 );
377 }
378
379 #[test]
380 fn test_sql_has_syntax_errors() {
381 let connection = Connection::open_memory(Some("test_sql_has_syntax_errors"));
382 let first_stmt =
383 "CREATE TABLE kv_store(key TEXT PRIMARY KEY, value TEXT NOT NULL) STRICT ;";
384 let second_stmt = "SELECT FROM";
385
386 let second_offset = connection.sql_has_syntax_error(second_stmt).unwrap().1;
387
388 let res = connection
389 .sql_has_syntax_error(&format!("{}\n{}", first_stmt, second_stmt))
390 .map(|(_, offset)| offset);
391
392 assert_eq!(res, Some(first_stmt.len() + second_offset + 1));
393 }
394
395 #[test]
396 fn test_alter_table_syntax() {
397 let connection = Connection::open_memory(Some("test_alter_table_syntax"));
398
399 assert!(connection
400 .sql_has_syntax_error("ALTER TABLE test ADD x TEXT")
401 .is_none());
402
403 assert!(connection
404 .sql_has_syntax_error("ALTER TABLE test AAD x TEXT")
405 .is_some());
406 }
407}