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Updatable eponymous virtual table

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gwenn 2022-03-19 10:39:31 +01:00 committed by Thom Chiovoloni
parent 3787f432a4
commit f04bec2fd5
2 changed files with 49 additions and 12 deletions
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6
src/vtab/csvtab.rs
View File

@ -31,7 +31,7 @@ use crate::ffi;
use crate::types::Null;
use crate::vtab::{
dequote, escape_double_quote, parse_boolean, read_only_module, Context, CreateVTab, IndexInfo,
VTab, VTabConfig, VTabConnection, VTabCursor, Values,
VTab, VTabConfig, VTabConnection, VTabCursor, VTabKind, Values,
};
use crate::{Connection, Error, Result};
@ -264,7 +264,9 @@ unsafe impl<'vtab> VTab<'vtab> for CsvTab {
}
}
impl CreateVTab<'_> for CsvTab {}
impl CreateVTab<'_> for CsvTab {
const KIND: VTabKind = VTabKind::Default;
}
/// A cursor for the CSV virtual table
#[repr(C)]

55
src/vtab/mod.rs
View File

@ -57,6 +57,19 @@ use crate::{str_to_cstring, Connection, Error, InnerConnection, Result};
// ffi::sqlite3_vtab => VTab
// ffi::sqlite3_vtab_cursor => VTabCursor
/// Virtual table kind
pub enum VTabKind {
/// Non-eponymous
Default,
/// [`create`](CreateVTab::create) == [`connect`](VTab::connect)
Eponymous,
/// No [`create`](CreateVTab::create) / [`destroy`](CreateVTab::destroy) or
/// not used
///
/// SQLite >= 3.9.0
EponymousOnly,
}
/// Virtual table module
///
/// (See [SQLite doc](https://sqlite.org/c3ref/module.html))
@ -93,11 +106,19 @@ pub fn update_module<'vtab, T: UpdateVTab<'vtab>>() -> &'static Module<'vtab, T>
&Module {
base: ffi::sqlite3_module {
iVersion: 2,
xCreate: Some(rust_create::<T>),
xCreate: match T::KIND {
VTabKind::EponymousOnly => None,
VTabKind::Eponymous => Some(rust_connect::<T>),
_ => Some(rust_create::<T>),
},
xConnect: Some(rust_connect::<T>),
xBestIndex: Some(rust_best_index::<T>),
xDisconnect: Some(rust_disconnect::<T>),
xDestroy: Some(rust_destroy::<T>),
xDestroy: match T::KIND {
VTabKind::EponymousOnly => None,
VTabKind::Eponymous => Some(rust_disconnect::<T>),
_ => Some(rust_destroy::<T>),
},
xOpen: Some(rust_open::<T>),
xClose: Some(rust_close::<T::Cursor>),
xFilter: Some(rust_filter::<T::Cursor>),
@ -133,11 +154,19 @@ pub fn read_only_module<'vtab, T: CreateVTab<'vtab>>() -> &'static Module<'vtab,
base: ffi::sqlite3_module {
// We don't use V3
iVersion: 2, // We don't use V2 or V3 features in read_only_module types
xCreate: Some(rust_create::<T>),
xCreate: match T::KIND {
VTabKind::EponymousOnly => None,
VTabKind::Eponymous => Some(rust_connect::<T>),
_ => Some(rust_create::<T>),
},
xConnect: Some(rust_connect::<T>),
xBestIndex: Some(rust_best_index::<T>),
xDisconnect: Some(rust_disconnect::<T>),
xDestroy: Some(rust_destroy::<T>),
xDestroy: match T::KIND {
VTabKind::EponymousOnly => None,
VTabKind::Eponymous => Some(rust_disconnect::<T>),
_ => Some(rust_destroy::<T>),
},
xOpen: Some(rust_open::<T>),
xClose: Some(rust_close::<T::Cursor>),
xFilter: Some(rust_filter::<T::Cursor>),
@ -247,7 +276,7 @@ impl VTabConnection {
}
}
/// Virtual table instance trait.
/// Eponymous-only virtual table instance trait.
///
/// # Safety
///
@ -288,10 +317,14 @@ pub unsafe trait VTab<'vtab>: Sized {
fn open(&'vtab self) -> Result<Self::Cursor>;
}
/// Non-eponymous virtual table instance trait.
/// Read-only virtual table instance trait.
///
/// (See [SQLite doc](https://sqlite.org/c3ref/vtab.html))
pub trait CreateVTab<'vtab>: VTab<'vtab> {
/// For [`EponymousOnly`](VTabKind::EponymousOnly),
/// [`create`](CreateVTab::create) and [`destroy`](CreateVTab::destroy) are
/// not called
const KIND: VTabKind;
/// Create a new instance of a virtual table in response to a CREATE VIRTUAL
/// TABLE statement. The `db` parameter is a pointer to the SQLite
/// database connection that is executing the CREATE VIRTUAL TABLE
@ -323,12 +356,14 @@ pub trait CreateVTab<'vtab>: VTab<'vtab> {
pub trait UpdateVTab<'vtab>: CreateVTab<'vtab> {
/// Delete rowid or PK
fn delete(&mut self, arg: ValueRef<'_>) -> Result<()>;
/// Insert: args[0] == NULL: old rowid or PK, args[1]: new rowid or PK,
/// args[2]: ... Return the new rowid.
/// Insert: `args[0] == NULL: old rowid or PK, args[1]: new rowid or PK,
/// args[2]: ...`
///
/// Return the new rowid.
// TODO Make the distinction between argv[1] == NULL and argv[1] != NULL ?
fn insert(&mut self, args: &Values<'_>) -> Result<i64>;
/// Update: args[0] != NULL: old rowid or PK, args[1]: new row id or PK,
/// args[2]: ...
/// Update: `args[0] != NULL: old rowid or PK, args[1]: new row id or PK,
/// args[2]: ...`
fn update(&mut self, args: &Values<'_>) -> Result<()>;
}