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) =
109 if let Some((table_to_alter, column)) = alter_table {
110 // ALTER TABLE is a weird statement. When preparing the statement the table's
111 // existence is checked *before* syntax checking any other part of the statement.
112 // Therefore, we need to make sure that the table has been created before calling
113 // prepare. As we don't want to trash whatever database this is connected to, we
114 // create a new in-memory DB to test.
115
116 let temp_connection = Connection::open_memory(None);
117 //This should always succeed, if it doesn't then you really should know about it
118 temp_connection
119 .exec(&format!("CREATE TABLE {table_to_alter}({column})"))
120 .unwrap()()
121 .unwrap();
122
123 sqlite3_prepare_v2(
124 temp_connection.sqlite3,
125 remaining_sql.as_ptr(),
126 -1,
127 &mut raw_statement,
128 &mut remaining_sql_ptr,
129 );
130
131 (
132 sqlite3_errcode(temp_connection.sqlite3),
133 sqlite3_error_offset(temp_connection.sqlite3),
134 sqlite3_errmsg(temp_connection.sqlite3),
135 Some(temp_connection),
136 )
137 } else {
138 sqlite3_prepare_v2(
139 self.sqlite3,
140 remaining_sql.as_ptr(),
141 -1,
142 &mut raw_statement,
143 &mut remaining_sql_ptr,
144 );
145 (
146 sqlite3_errcode(self.sqlite3),
147 sqlite3_error_offset(self.sqlite3),
148 sqlite3_errmsg(self.sqlite3),
149 None,
150 )
151 };
152
153 sqlite3_finalize(raw_statement);
154
155 if res == 1 && offset >= 0 {
156 let sub_statement_correction =
157 remaining_sql.as_ptr() as usize - sql_start as usize;
158 let err_msg =
159 String::from_utf8_lossy(CStr::from_ptr(message as *const _).to_bytes())
160 .into_owned();
161
162 return Some((err_msg, offset as usize + sub_statement_correction));
163 }
164 remaining_sql = CStr::from_ptr(remaining_sql_ptr);
165 alter_table = None;
166 }
167 }
168 None
169 }
170
171 pub(crate) fn last_error(&self) -> Result<()> {
172 unsafe {
173 let code = sqlite3_errcode(self.sqlite3);
174 const NON_ERROR_CODES: &[i32] = &[SQLITE_OK, SQLITE_ROW];
175 if NON_ERROR_CODES.contains(&code) {
176 return Ok(());
177 }
178
179 let message = sqlite3_errmsg(self.sqlite3);
180 let message = if message.is_null() {
181 None
182 } else {
183 Some(
184 String::from_utf8_lossy(CStr::from_ptr(message as *const _).to_bytes())
185 .into_owned(),
186 )
187 };
188
189 Err(anyhow!(
190 "Sqlite call failed with code {} and message: {:?}",
191 code as isize,
192 message
193 ))
194 }
195 }
196
197 pub(crate) fn with_write<T>(&self, callback: impl FnOnce(&Connection) -> T) -> T {
198 *self.write.borrow_mut() = true;
199 let result = callback(self);
200 *self.write.borrow_mut() = false;
201 result
202 }
203}
204
205fn parse_alter_table(remaining_sql_str: &str) -> Option<(String, String)> {
206 let remaining_sql_str = remaining_sql_str.to_lowercase();
207 if remaining_sql_str.starts_with("alter") {
208 if let Some(table_offset) = remaining_sql_str.find("table") {
209 let after_table_offset = table_offset + "table".len();
210 let table_to_alter = remaining_sql_str
211 .chars()
212 .skip(after_table_offset)
213 .skip_while(|c| c.is_whitespace())
214 .take_while(|c| !c.is_whitespace())
215 .collect::<String>();
216 if !table_to_alter.is_empty() {
217 let column_name =
218 if let Some(rename_offset) = remaining_sql_str.find("rename column") {
219 let after_rename_offset = rename_offset + "rename column".len();
220 remaining_sql_str
221 .chars()
222 .skip(after_rename_offset)
223 .skip_while(|c| c.is_whitespace())
224 .take_while(|c| !c.is_whitespace())
225 .collect::<String>()
226 } else if let Some(drop_offset) = remaining_sql_str.find("drop column") {
227 let after_drop_offset = drop_offset + "drop column".len();
228 remaining_sql_str
229 .chars()
230 .skip(after_drop_offset)
231 .skip_while(|c| c.is_whitespace())
232 .take_while(|c| !c.is_whitespace())
233 .collect::<String>()
234 } else {
235 "__place_holder_column_for_syntax_checking".to_string()
236 };
237 return Some((table_to_alter, column_name));
238 }
239 }
240 }
241 None
242}
243
244impl Drop for Connection {
245 fn drop(&mut self) {
246 unsafe { sqlite3_close(self.sqlite3) };
247 }
248}
249
250#[cfg(test)]
251mod test {
252 use anyhow::Result;
253 use indoc::indoc;
254
255 use crate::connection::Connection;
256
257 #[test]
258 fn string_round_trips() -> Result<()> {
259 let connection = Connection::open_memory(Some("string_round_trips"));
260 connection
261 .exec(indoc! {"
262 CREATE TABLE text (
263 text TEXT
264 );"})
265 .unwrap()()
266 .unwrap();
267
268 let text = "Some test text";
269
270 connection
271 .exec_bound("INSERT INTO text (text) VALUES (?);")
272 .unwrap()(text)
273 .unwrap();
274
275 assert_eq!(
276 connection.select_row("SELECT text FROM text;").unwrap()().unwrap(),
277 Some(text.to_string())
278 );
279
280 Ok(())
281 }
282
283 #[test]
284 fn tuple_round_trips() {
285 let connection = Connection::open_memory(Some("tuple_round_trips"));
286 connection
287 .exec(indoc! {"
288 CREATE TABLE test (
289 text TEXT,
290 integer INTEGER,
291 blob BLOB
292 );"})
293 .unwrap()()
294 .unwrap();
295
296 let tuple1 = ("test".to_string(), 64, vec![0, 1, 2, 4, 8, 16, 32, 64]);
297 let tuple2 = ("test2".to_string(), 32, vec![64, 32, 16, 8, 4, 2, 1, 0]);
298
299 let mut insert = connection
300 .exec_bound::<(String, usize, Vec<u8>)>(
301 "INSERT INTO test (text, integer, blob) VALUES (?, ?, ?)",
302 )
303 .unwrap();
304
305 insert(tuple1.clone()).unwrap();
306 insert(tuple2.clone()).unwrap();
307
308 assert_eq!(
309 connection
310 .select::<(String, usize, Vec<u8>)>("SELECT * FROM test")
311 .unwrap()()
312 .unwrap(),
313 vec![tuple1, tuple2]
314 );
315 }
316
317 #[test]
318 fn bool_round_trips() {
319 let connection = Connection::open_memory(Some("bool_round_trips"));
320 connection
321 .exec(indoc! {"
322 CREATE TABLE bools (
323 t INTEGER,
324 f INTEGER
325 );"})
326 .unwrap()()
327 .unwrap();
328
329 connection
330 .exec_bound("INSERT INTO bools(t, f) VALUES (?, ?)")
331 .unwrap()((true, false))
332 .unwrap();
333
334 assert_eq!(
335 connection
336 .select_row::<(bool, bool)>("SELECT * FROM bools;")
337 .unwrap()()
338 .unwrap(),
339 Some((true, false))
340 );
341 }
342
343 #[test]
344 fn backup_works() {
345 let connection1 = Connection::open_memory(Some("backup_works"));
346 connection1
347 .exec(indoc! {"
348 CREATE TABLE blobs (
349 data BLOB
350 );"})
351 .unwrap()()
352 .unwrap();
353 let blob = vec![0, 1, 2, 4, 8, 16, 32, 64];
354 connection1
355 .exec_bound::<Vec<u8>>("INSERT INTO blobs (data) VALUES (?);")
356 .unwrap()(blob.clone())
357 .unwrap();
358
359 // Backup connection1 to connection2
360 let connection2 = Connection::open_memory(Some("backup_works_other"));
361 connection1.backup_main(&connection2).unwrap();
362
363 // Delete the added blob and verify its deleted on the other side
364 let read_blobs = connection1
365 .select::<Vec<u8>>("SELECT * FROM blobs;")
366 .unwrap()()
367 .unwrap();
368 assert_eq!(read_blobs, vec![blob]);
369 }
370
371 #[test]
372 fn multi_step_statement_works() {
373 let connection = Connection::open_memory(Some("multi_step_statement_works"));
374
375 connection
376 .exec(indoc! {"
377 CREATE TABLE test (
378 col INTEGER
379 )"})
380 .unwrap()()
381 .unwrap();
382
383 connection
384 .exec(indoc! {"
385 INSERT INTO test(col) VALUES (2)"})
386 .unwrap()()
387 .unwrap();
388
389 assert_eq!(
390 connection
391 .select_row::<usize>("SELECT * FROM test")
392 .unwrap()()
393 .unwrap(),
394 Some(2)
395 );
396 }
397
398 #[test]
399 fn test_sql_has_syntax_errors() {
400 let connection = Connection::open_memory(Some("test_sql_has_syntax_errors"));
401 let first_stmt =
402 "CREATE TABLE kv_store(key TEXT PRIMARY KEY, value TEXT NOT NULL) STRICT ;";
403 let second_stmt = "SELECT FROM";
404
405 let second_offset = connection.sql_has_syntax_error(second_stmt).unwrap().1;
406
407 let res = connection
408 .sql_has_syntax_error(&format!("{}\n{}", first_stmt, second_stmt))
409 .map(|(_, offset)| offset);
410
411 assert_eq!(res, Some(first_stmt.len() + second_offset + 1));
412 }
413
414 #[test]
415 fn test_alter_table_syntax() {
416 let connection = Connection::open_memory(Some("test_alter_table_syntax"));
417
418 assert!(connection
419 .sql_has_syntax_error("ALTER TABLE test ADD x TEXT")
420 .is_none());
421
422 assert!(connection
423 .sql_has_syntax_error("ALTER TABLE test AAD x TEXT")
424 .is_some());
425 }
426}