Refactor hooks

This commit is contained in:
gwenn 2018-08-05 10:58:00 +02:00
parent 11ee69b571
commit 437f7dab42

View File

@ -1,6 +1,7 @@
//! Commit, Data Change and Rollback Notification Callbacks //! Commit, Data Change and Rollback Notification Callbacks
#![allow(non_camel_case_types)] #![allow(non_camel_case_types)]
use std::mem::size_of;
use std::ptr; use std::ptr;
use std::os::raw::{c_int, c_char, c_void}; use std::os::raw::{c_int, c_char, c_void};
@ -94,8 +95,9 @@ impl Connection {
/// Register a callback function to be invoked whenever a transaction is committed. /// Register a callback function to be invoked whenever a transaction is committed.
/// ///
/// The callback returns `true` to rollback. /// The callback returns `true` to rollback.
pub fn commit_hook<F>(&self, hook: F) pub fn commit_hook<F>(&self, hook: Option<F>)
where F: FnMut() -> bool where
F: FnMut() -> bool,
{ {
self.db.borrow_mut().commit_hook(hook); self.db.borrow_mut().commit_hook(hook);
} }
@ -103,8 +105,9 @@ impl Connection {
/// Register a callback function to be invoked whenever a transaction is committed. /// Register a callback function to be invoked whenever a transaction is committed.
/// ///
/// The callback returns `true` to rollback. /// The callback returns `true` to rollback.
pub fn rollback_hook<F>(&self, hook: F) pub fn rollback_hook<F>(&self, hook: Option<F>)
where F: FnMut() where
F: FnMut(),
{ {
self.db.borrow_mut().rollback_hook(hook); self.db.borrow_mut().rollback_hook(hook);
} }
@ -118,99 +121,104 @@ impl Connection {
/// - the name of the database ("main", "temp", ...), /// - the name of the database ("main", "temp", ...),
/// - the name of the table that is updated, /// - the name of the table that is updated,
/// - the ROWID of the row that is updated. /// - the ROWID of the row that is updated.
pub fn update_hook<F>(&self, hook: F) pub fn update_hook<F>(&self, hook: Option<F>)
where F: FnMut(Action, &str, &str, i64) where
F: FnMut(Action, &str, &str, i64),
{ {
self.db.borrow_mut().update_hook(hook); self.db.borrow_mut().update_hook(hook);
} }
/// Remove hook installed by `update_hook`.
pub fn remove_update_hook(&self) {
self.db.borrow_mut().remove_update_hook();
}
/// Remove hook installed by `commit_hook`.
pub fn remove_commit_hook(&self) {
self.db.borrow_mut().remove_commit_hook();
}
/// Remove hook installed by `rollback_hook`.
pub fn remove_rollback_hook(&self) {
self.db.borrow_mut().remove_rollback_hook();
}
} }
impl InnerConnection { impl InnerConnection {
pub fn remove_hooks(&mut self) { pub fn remove_hooks(&mut self) {
self.remove_update_hook(); self.update_hook(None::<fn(Action, &str, &str, i64)>);
self.remove_commit_hook(); self.commit_hook(None::<fn() -> bool>);
self.remove_rollback_hook(); self.rollback_hook(None::<fn()>);
} }
fn commit_hook<F>(&self, hook: F) fn commit_hook<F>(&self, hook: Option<F>)
where F: FnMut() -> bool where
F: FnMut() -> bool,
{ {
assert_eq!(size_of::<*mut F>(), size_of::<*mut c_void>());
unsafe extern "C" fn call_boxed_closure<F>(p_arg: *mut c_void) -> c_int unsafe extern "C" fn call_boxed_closure<F>(p_arg: *mut c_void) -> c_int
where F: FnMut() -> bool where
F: FnMut() -> bool,
{ {
let boxed_hook: *mut F = p_arg as *mut F; let boxed_hook: *mut F = p_arg as *mut F;
assert!(!boxed_hook.is_null(), if (*boxed_hook)() {
"Internal error - null function pointer"); 1
} else {
if (*boxed_hook)() { 1 } else { 0 } 0
}
} }
let previous_hook = { let previous_hook = match hook {
Some(hook) => {
let boxed_hook: *mut F = Box::into_raw(Box::new(hook)); let boxed_hook: *mut F = Box::into_raw(Box::new(hook));
unsafe { unsafe {
ffi::sqlite3_commit_hook(self.db(), ffi::sqlite3_commit_hook(
self.db(),
Some(call_boxed_closure::<F>), Some(call_boxed_closure::<F>),
boxed_hook as *mut _) boxed_hook as *mut _,
)
} }
}
_ => unsafe { ffi::sqlite3_commit_hook(self.db(), None, ptr::null_mut()) },
}; };
free_boxed_hook(previous_hook); free_boxed_hook(previous_hook);
} }
fn rollback_hook<F>(&self, hook: F) fn rollback_hook<F>(&self, hook: Option<F>)
where F: FnMut() where
F: FnMut(),
{ {
assert_eq!(size_of::<*mut F>(), size_of::<*mut c_void>());
unsafe extern "C" fn call_boxed_closure<F>(p_arg: *mut c_void) unsafe extern "C" fn call_boxed_closure<F>(p_arg: *mut c_void)
where F: FnMut() where
F: FnMut(),
{ {
let boxed_hook: *mut F = p_arg as *mut F; let boxed_hook: *mut F = p_arg as *mut F;
assert!(!boxed_hook.is_null(),
"Internal error - null function pointer");
(*boxed_hook)(); (*boxed_hook)();
} }
let previous_hook = { let previous_hook = match hook {
Some(hook) => {
let boxed_hook: *mut F = Box::into_raw(Box::new(hook)); let boxed_hook: *mut F = Box::into_raw(Box::new(hook));
unsafe { unsafe {
ffi::sqlite3_rollback_hook(self.db(), ffi::sqlite3_rollback_hook(
self.db(),
Some(call_boxed_closure::<F>), Some(call_boxed_closure::<F>),
boxed_hook as *mut _) boxed_hook as *mut _,
)
} }
}
_ => unsafe { ffi::sqlite3_rollback_hook(self.db(), None, ptr::null_mut()) },
}; };
free_boxed_hook(previous_hook); free_boxed_hook(previous_hook);
} }
fn update_hook<F>(&mut self, hook: F) fn update_hook<F>(&mut self, hook: Option<F>)
where F: FnMut(Action, &str, &str, i64) where
F: FnMut(Action, &str, &str, i64),
{ {
unsafe extern "C" fn call_boxed_closure<F>(p_arg: *mut c_void, assert_eq!(size_of::<*mut F>(), size_of::<*mut c_void>());
unsafe extern "C" fn call_boxed_closure<F>(
p_arg: *mut c_void,
action_code: c_int, action_code: c_int,
db_str: *const c_char, db_str: *const c_char,
tbl_str: *const c_char, tbl_str: *const c_char,
row_id: i64) row_id: i64,
where F: FnMut(Action, &str, &str, i64) ) where
F: FnMut(Action, &str, &str, i64),
{ {
use std::ffi::CStr; use std::ffi::CStr;
use std::str; use std::str;
let boxed_hook: *mut F = p_arg as *mut F; let boxed_hook: *mut F = p_arg as *mut F;
assert!(!boxed_hook.is_null(),
"Internal error - null function pointer");
let action = Action::from(action_code); let action = Action::from(action_code);
let db_name = { let db_name = {
@ -225,36 +233,26 @@ impl InnerConnection {
(*boxed_hook)(action, db_name, tbl_name, row_id); (*boxed_hook)(action, db_name, tbl_name, row_id);
} }
let previous_hook = { let previous_hook = match hook {
Some(hook) => {
let boxed_hook: *mut F = Box::into_raw(Box::new(hook)); let boxed_hook: *mut F = Box::into_raw(Box::new(hook));
unsafe { unsafe {
ffi::sqlite3_update_hook(self.db(), ffi::sqlite3_update_hook(
self.db(),
Some(call_boxed_closure::<F>), Some(call_boxed_closure::<F>),
boxed_hook as *mut _) boxed_hook as *mut _,
)
} }
}
_ => unsafe { ffi::sqlite3_update_hook(self.db(), None, ptr::null_mut()) },
}; };
free_boxed_hook(previous_hook); free_boxed_hook(previous_hook);
} }
fn remove_update_hook(&mut self) {
let previous_hook = unsafe { ffi::sqlite3_update_hook(self.db(), None, ptr::null_mut()) };
free_boxed_hook(previous_hook);
}
fn remove_commit_hook(&mut self) {
let previous_hook = unsafe { ffi::sqlite3_commit_hook(self.db(), None, ptr::null_mut()) };
free_boxed_hook(previous_hook);
}
fn remove_rollback_hook(&mut self) {
let previous_hook = unsafe { ffi::sqlite3_rollback_hook(self.db(), None, ptr::null_mut()) };
free_boxed_hook(previous_hook);
}
} }
fn free_boxed_hook(hook: *mut c_void) { fn free_boxed_hook(hook: *mut c_void) {
if !hook.is_null() { if !hook.is_null() {
// TODO make sure that size_of::<*mut F>() is always equal to size_of::<*mut c_void>() // make sure that size_of::<*mut F>() is always equal to size_of::<*mut c_void>()
let _: Box<*mut c_void> = unsafe { Box::from_raw(hook as *mut _) }; let _: Box<*mut c_void> = unsafe { Box::from_raw(hook as *mut _) };
} }
} }
@ -269,10 +267,10 @@ mod test {
let db = Connection::open_in_memory().unwrap(); let db = Connection::open_in_memory().unwrap();
let mut called = false; let mut called = false;
db.commit_hook(|| { db.commit_hook(Some(|| {
called = true; called = true;
false false
}); }));
db.execute_batch("BEGIN; CREATE TABLE foo (t TEXT); COMMIT;") db.execute_batch("BEGIN; CREATE TABLE foo (t TEXT); COMMIT;")
.unwrap(); .unwrap();
assert!(called); assert!(called);
@ -283,7 +281,9 @@ mod test {
let db = Connection::open_in_memory().unwrap(); let db = Connection::open_in_memory().unwrap();
let mut called = false; let mut called = false;
db.rollback_hook(|| { called = true; }); db.rollback_hook(Some(|| {
called = true;
}));
db.execute_batch("BEGIN; CREATE TABLE foo (t TEXT); ROLLBACK;") db.execute_batch("BEGIN; CREATE TABLE foo (t TEXT); ROLLBACK;")
.unwrap(); .unwrap();
assert!(called); assert!(called);
@ -294,13 +294,13 @@ mod test {
let db = Connection::open_in_memory().unwrap(); let db = Connection::open_in_memory().unwrap();
let mut called = false; let mut called = false;
db.update_hook(|action, db, tbl, row_id| { db.update_hook(Some(|action, db: &str, tbl: &str, row_id| {
assert_eq!(Action::SQLITE_INSERT, action); assert_eq!(Action::SQLITE_INSERT, action);
assert_eq!("main", db); assert_eq!("main", db);
assert_eq!("foo", tbl); assert_eq!("foo", tbl);
assert_eq!(1, row_id); assert_eq!(1, row_id);
called = true; called = true;
}); }));
db.execute_batch("CREATE TABLE foo (t TEXT)").unwrap(); db.execute_batch("CREATE TABLE foo (t TEXT)").unwrap();
db.execute_batch("INSERT INTO foo VALUES ('lisa')").unwrap(); db.execute_batch("INSERT INTO foo VALUES ('lisa')").unwrap();
assert!(called); assert!(called);