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Copy pathstatement.rs
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Copy pathstatement.rs
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206 lines (169 loc) · 5.89 KB
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use core::ptr::{null, null_mut, NonNull};
use std::collections::HashMap;
use std::ffi::CStr;
use std::os::raw::c_int;
use libsqlite3_sys::{
sqlite3_bind_parameter_count, sqlite3_column_count, sqlite3_column_decltype,
sqlite3_column_name, sqlite3_finalize, sqlite3_prepare_v3, sqlite3_reset, sqlite3_step,
sqlite3_stmt, SQLITE_DONE, SQLITE_OK, SQLITE_PREPARE_NO_VTAB, SQLITE_PREPARE_PERSISTENT,
SQLITE_ROW,
};
use crate::sqlite::worker::Worker;
use crate::sqlite::SqliteError;
use crate::sqlite::{SqliteArguments, SqliteConnection};
pub(crate) enum Step {
Done,
Row,
}
#[derive(Clone, Copy)]
pub(super) struct SqliteStatementHandle(NonNull<sqlite3_stmt>);
pub(super) struct SqliteStatement {
worker: Worker,
pub(super) tail: usize,
pub(super) handle: SqliteStatementHandle,
pub(super) columns: HashMap<String, usize>,
}
// SAFE: See notes for the Send impl on [SqliteConnection].
#[allow(unsafe_code)]
unsafe impl Send for SqliteStatementHandle {}
#[allow(unsafe_code)]
unsafe impl Sync for SqliteStatementHandle {}
impl SqliteStatement {
pub(super) fn handle(&self) -> *mut sqlite3_stmt {
self.handle.0.as_ptr()
}
pub(super) fn new(
conn: &mut SqliteConnection,
query: &mut &str,
persistent: bool,
) -> crate::Result<Self> {
// TODO: Error on queries that are too large
let query_ptr = query.as_bytes().as_ptr() as *const i8;
let query_len = query.len() as i32;
let mut statement_handle: *mut sqlite3_stmt = null_mut();
let mut flags = SQLITE_PREPARE_NO_VTAB;
let mut tail: *const i8 = null();
if persistent {
// SQLITE_PREPARE_PERSISTENT
// The SQLITE_PREPARE_PERSISTENT flag is a hint to the query
// planner that the prepared statement will be retained for a long time
// and probably reused many times.
flags |= SQLITE_PREPARE_PERSISTENT;
}
// <https://www.sqlite.org/c3ref/prepare.html>
#[allow(unsafe_code)]
let status = unsafe {
sqlite3_prepare_v3(
conn.handle(),
query_ptr,
query_len,
flags as u32,
&mut statement_handle,
&mut tail,
)
};
// If pzTail is not NULL then *pzTail is made to point to the first byte
// past the end of the first SQL statement in zSql.
let tail = (tail as usize) - (query_ptr as usize);
*query = &query[tail..].trim();
if status != SQLITE_OK {
return Err(SqliteError::new(status).into());
}
let mut self_ = Self {
worker: conn.worker.clone(),
handle: SqliteStatementHandle(NonNull::new(statement_handle).unwrap()),
columns: HashMap::new(),
tail,
};
// Prepare a column hash map for use in pulling values from a column by name
let count = self_.num_columns();
self_.columns.reserve(count);
for i in 0..count {
self_.columns.insert(self_.column_name(i).to_owned(), i);
}
Ok(self_)
}
pub(super) fn num_columns(&self) -> usize {
// https://sqlite.org/c3ref/column_count.html
#[allow(unsafe_code)]
let count = unsafe { sqlite3_column_count(self.handle()) };
count as usize
}
pub(super) fn column_name(&self, index: usize) -> &str {
// https://sqlite.org/c3ref/column_name.html
#[allow(unsafe_code)]
let name = unsafe {
let ptr = sqlite3_column_name(self.handle(), index as c_int);
debug_assert!(!ptr.is_null());
CStr::from_ptr(ptr)
};
name.to_str().unwrap()
}
pub(super) fn column_decltype(&self, index: usize) -> Option<&str> {
// https://sqlite.org/c3ref/column_name.html
#[allow(unsafe_code)]
let name = unsafe {
let ptr = sqlite3_column_decltype(self.handle(), index as c_int);
if ptr.is_null() {
None
} else {
Some(CStr::from_ptr(ptr))
}
};
name.map(|s| s.to_str().unwrap())
}
pub(super) fn params(&self) -> usize {
// https://www.hwaci.com/sw/sqlite/c3ref/bind_parameter_count.html
#[allow(unsafe_code)]
let num = unsafe { sqlite3_bind_parameter_count(self.handle()) };
num as usize
}
pub(super) fn bind(&mut self, arguments: &mut SqliteArguments) -> crate::Result<()> {
for index in 0..self.params() {
if let Some(value) = arguments.next() {
value.bind(self, index + 1)?;
} else {
break;
}
}
Ok(())
}
pub(super) fn reset(&mut self) {
// https://sqlite.org/c3ref/reset.html
// the status value of reset is ignored because it merely propagates
// the status of the most recently invoked step function
#[allow(unsafe_code)]
let _ = unsafe { sqlite3_reset(self.handle()) };
}
pub(super) async fn step(&mut self) -> crate::Result<Step> {
// https://sqlite.org/c3ref/step.html
let status = self
.worker
.run({
let handle = self.handle;
move || {
#[allow(unsafe_code)]
unsafe {
sqlite3_step(handle.0.as_ptr())
}
}
})
.await;
match status {
SQLITE_DONE => Ok(Step::Done),
SQLITE_ROW => Ok(Step::Row),
status => {
return Err(SqliteError::new(status).into());
}
}
}
}
impl Drop for SqliteStatement {
fn drop(&mut self) {
// https://sqlite.org/c3ref/finalize.html
#[allow(unsafe_code)]
unsafe {
let _ = sqlite3_finalize(self.handle());
}
}
}