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use std::marker::PhantomData;
use std::ops::{Deref, DerefMut};
use std::path::Path;
use libc::{c_char, c_int, c_void};
use crate::error::Result;
use crate::statement::Statement;
/// A database connection.
pub struct Connection {
raw: Raw,
busy_callback: Option<Box<dyn FnMut(usize) -> bool + Send>>,
phantom: PhantomData<ffi::sqlite3>,
}
/// A thread-safe database connection.
pub struct ConnectionWithFullMutex(Connection);
/// Flags for opening a database connection.
#[derive(Clone, Copy, Debug)]
pub struct OpenFlags(c_int);
struct Raw(*mut ffi::sqlite3);
impl Connection {
/// Open a read-write connection to a new or existing database.
pub fn open<T: AsRef<Path>>(path: T) -> Result<Connection> {
Connection::open_with_flags(path, OpenFlags::new().set_create().set_read_write())
}
/// Open a connection with specific flags.
pub fn open_with_flags<T: AsRef<Path>>(path: T, flags: OpenFlags) -> Result<Connection> {
let mut raw = std::ptr::null_mut();
unsafe {
let code = ffi::sqlite3_open_v2(
path_to_cstr!(path.as_ref()).as_ptr(),
&mut raw,
flags.0,
std::ptr::null(),
);
match code {
ffi::SQLITE_OK => {}
code => match crate::error::last(raw) {
Some(error) => {
ffi::sqlite3_close(raw);
return Err(error);
}
_ => {
ffi::sqlite3_close(raw);
return Err(crate::error::Error {
code: Some(code as isize),
message: None,
});
}
},
}
}
Ok(Connection {
raw: Raw(raw),
busy_callback: None,
phantom: PhantomData,
})
}
/// Open a thread-safe read-write connection to a new or existing database.
pub fn open_with_full_mutex<T: AsRef<Path>>(path: T) -> Result<ConnectionWithFullMutex> {
Connection::open_with_flags(
path,
OpenFlags::new()
.set_create()
.set_read_write()
.set_full_mutex(),
)
.map(ConnectionWithFullMutex)
}
/// Execute a statement without processing the resulting rows if any.
#[inline]
pub fn execute<T: AsRef<str>>(&self, statement: T) -> Result<()> {
unsafe {
ok!(
self.raw.0,
ffi::sqlite3_exec(
self.raw.0,
str_to_cstr!(statement.as_ref()).as_ptr(),
None,
std::ptr::null_mut(),
std::ptr::null_mut(),
)
);
}
Ok(())
}
/// Execute a statement and process the resulting rows as plain text.
///
/// The callback is triggered for each row. If the callback returns `false`,
/// no more rows will be processed. For large queries and non-string data
/// types, prepared statement are highly preferable; see `prepare`.
#[inline]
pub fn iterate<T: AsRef<str>, F>(&self, statement: T, callback: F) -> Result<()>
where
F: FnMut(&[(&str, Option<&str>)]) -> bool,
{
unsafe {
let callback = Box::new(callback);
ok!(
self.raw.0,
ffi::sqlite3_exec(
self.raw.0,
str_to_cstr!(statement.as_ref()).as_ptr(),
Some(process_callback::<F>),
&*callback as *const F as *mut F as *mut _,
std::ptr::null_mut(),
)
);
}
Ok(())
}
/// Create a prepared statement.
#[inline]
pub fn prepare<T: AsRef<str>>(&self, statement: T) -> Result<Statement<'_>> {
crate::statement::new(self.raw.0, statement)
}
/// Return the number of rows inserted, updated, or deleted by the most
/// recent INSERT, UPDATE, or DELETE statement.
#[inline]
pub fn change_count(&self) -> usize {
unsafe { ffi::sqlite3_changes(self.raw.0) as usize }
}
/// Return the total number of rows inserted, updated, and deleted by all
/// INSERT, UPDATE, and DELETE statements since the connection was opened.
#[inline]
pub fn total_change_count(&self) -> usize {
unsafe { ffi::sqlite3_total_changes(self.raw.0) as usize }
}
/// Set a callback for handling busy events.
///
/// The callback is triggered when the database cannot perform an operation
/// due to processing of some other request. If the callback returns `true`,
/// the operation will be repeated.
pub fn set_busy_handler<F>(&mut self, callback: F) -> Result<()>
where
F: FnMut(usize) -> bool + Send + 'static,
{
self.remove_busy_handler()?;
unsafe {
let callback = Box::new(callback);
let result = ffi::sqlite3_busy_handler(
self.raw.0,
Some(busy_callback::<F>),
&*callback as *const F as *mut F as *mut _,
);
self.busy_callback = Some(callback);
ok!(self.raw.0, result);
}
Ok(())
}
/// Set an implicit callback for handling busy events that tries to repeat
/// rejected operations until a timeout expires.
#[inline]
pub fn set_busy_timeout(&mut self, milliseconds: usize) -> Result<()> {
unsafe {
ok!(
self.raw.0,
ffi::sqlite3_busy_timeout(self.raw.0, milliseconds as c_int)
);
}
Ok(())
}
/// Remove the callback handling busy events.
#[inline]
pub fn remove_busy_handler(&mut self) -> Result<()> {
self.busy_callback = None;
unsafe {
ok!(
self.raw.0,
ffi::sqlite3_busy_handler(self.raw.0, None, std::ptr::null_mut())
);
}
Ok(())
}
#[doc(hidden)]
#[inline]
pub fn as_raw(&self) -> *mut ffi::sqlite3 {
self.raw.0
}
}
impl Drop for Connection {
#[inline]
#[allow(unused_must_use)]
fn drop(&mut self) {
self.remove_busy_handler();
unsafe { ffi::sqlite3_close(self.raw.0) };
}
}
impl OpenFlags {
/// Create flags for opening a database connection.
#[inline]
pub fn new() -> Self {
OpenFlags(0)
}
/// Create the database if it does not already exist.
pub fn set_create(mut self) -> Self {
self.0 |= ffi::SQLITE_OPEN_CREATE;
self
}
/// Open the database in the serialized [threading mode][1].
///
/// [1]: https://www.sqlite.org/threadsafe.html
pub fn set_full_mutex(mut self) -> Self {
self.0 |= ffi::SQLITE_OPEN_FULLMUTEX;
self
}
/// Opens the database in the multi-thread [threading mode][1].
///
/// [1]: https://www.sqlite.org/threadsafe.html
pub fn set_no_mutex(mut self) -> Self {
self.0 |= ffi::SQLITE_OPEN_NOMUTEX;
self
}
/// Open the database for reading only.
pub fn set_read_only(mut self) -> Self {
self.0 |= ffi::SQLITE_OPEN_READONLY;
self
}
/// Open the database for reading and writing.
pub fn set_read_write(mut self) -> Self {
self.0 |= ffi::SQLITE_OPEN_READWRITE;
self
}
}
impl Default for OpenFlags {
#[inline]
fn default() -> Self {
Self::new()
}
}
impl Deref for ConnectionWithFullMutex {
type Target = Connection;
#[inline]
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl DerefMut for ConnectionWithFullMutex {
#[inline]
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0
}
}
unsafe impl Sync for ConnectionWithFullMutex {}
unsafe impl Send for Raw {}
extern "C" fn busy_callback<F>(callback: *mut c_void, attempts: c_int) -> c_int
where
F: FnMut(usize) -> bool,
{
unsafe { c_int::from((*(callback as *mut F))(attempts as usize)) }
}
extern "C" fn process_callback<F>(
callback: *mut c_void,
count: c_int,
values: *mut *mut c_char,
columns: *mut *mut c_char,
) -> c_int
where
F: FnMut(&[(&str, Option<&str>)]) -> bool,
{
unsafe {
let mut pairs = Vec::with_capacity(count as usize);
for index in 0..(count as isize) {
let column = {
let pointer = *columns.offset(index);
debug_assert!(!pointer.is_null());
c_str_to_str!(pointer).unwrap()
};
let value = {
let pointer = *values.offset(index);
if pointer.is_null() {
None
} else {
Some(c_str_to_str!(pointer).unwrap())
}
};
pairs.push((column, value));
}
c_int::from(!(*(callback as *mut F))(&pairs))
}
}