story-kit: merge 260_refactor_upgrade_libsqlite3_sys

vendor/rusqlite/src/vtab/array.rs

@@ -0,0 +1,221 @@
+//! Array Virtual Table.
+//!
+//! Note: `rarray`, not `carray` is the name of the table valued function we
+//! define.
+//!
+//! Port of [carray](http://www.sqlite.org/cgi/src/finfo?name=ext/misc/carray.c)
+//! C extension: `https://www.sqlite.org/carray.html`
+//!
+//! # Example
+//!
+//! ```rust,no_run
+//! # use rusqlite::{types::Value, Connection, Result, params};
+//! # use std::rc::Rc;
+//! fn example(db: &Connection) -> Result<()> {
+//!     // Note: This should be done once (usually when opening the DB).
+//!     rusqlite::vtab::array::load_module(&db)?;
+//!     let v = [1i64, 2, 3, 4];
+//!     // Note: A `Rc<Vec<Value>>` must be used as the parameter.
+//!     let values = Rc::new(v.iter().copied().map(Value::from).collect::<Vec<Value>>());
+//!     let mut stmt = db.prepare("SELECT value from rarray(?1);")?;
+//!     let rows = stmt.query_map([values], |row| row.get::<_, i64>(0))?;
+//!     for value in rows {
+//!         println!("{}", value?);
+//!     }
+//!     Ok(())
+//! }
+//! ```
+
+use std::ffi::{c_int, CStr};
+use std::marker::PhantomData;
+use std::rc::Rc;
+
+use crate::ffi;
+use crate::types::{ToSql, ToSqlOutput, Value};
+use crate::vtab::{
+    eponymous_only_module, Context, Filters, IndexConstraintOp, IndexInfo, VTab, VTabConnection,
+    VTabCursor,
+};
+use crate::{Connection, Result};
+
+// http://sqlite.org/bindptr.html
+
+const ARRAY_TYPE: &CStr = c"rarray";
+
+/// Array parameter / pointer
+pub type Array = Rc<Vec<Value>>;
+
+impl ToSql for Array {
+    #[inline]
+    fn to_sql(&self) -> Result<ToSqlOutput<'_>> {
+        Ok(ToSqlOutput::from_rc(self.clone(), ARRAY_TYPE))
+    }
+}
+
+/// Register the "rarray" module.
+pub fn load_module(conn: &Connection) -> Result<()> {
+    let aux: Option<()> = None;
+    conn.create_module(c"rarray", eponymous_only_module::<ArrayTab>(), aux)
+}
+
+// Column numbers
+// const CARRAY_COLUMN_VALUE : c_int = 0;
+const CARRAY_COLUMN_POINTER: c_int = 1;
+
+/// An instance of the Array virtual table
+#[repr(C)]
+struct ArrayTab {
+    /// Base class. Must be first
+    base: ffi::sqlite3_vtab,
+}
+
+unsafe impl<'vtab> VTab<'vtab> for ArrayTab {
+    type Aux = ();
+    type Cursor = ArrayTabCursor<'vtab>;
+
+    fn connect(
+        _: &mut VTabConnection,
+        _aux: Option<&()>,
+        _args: &[&[u8]],
+    ) -> Result<(String, Self)> {
+        let vtab = Self {
+            base: ffi::sqlite3_vtab::default(),
+        };
+        Ok(("CREATE TABLE x(value,pointer hidden)".to_owned(), vtab))
+    }
+
+    fn best_index(&self, info: &mut IndexInfo) -> Result<()> {
+        // Index of the pointer= constraint
+        let mut ptr_idx = false;
+        for (constraint, mut constraint_usage) in info.constraints_and_usages() {
+            if !constraint.is_usable() {
+                continue;
+            }
+            if constraint.operator() != IndexConstraintOp::SQLITE_INDEX_CONSTRAINT_EQ {
+                continue;
+            }
+            if let CARRAY_COLUMN_POINTER = constraint.column() {
+                ptr_idx = true;
+                constraint_usage.set_argv_index(1);
+                constraint_usage.set_omit(true);
+            }
+        }
+        if ptr_idx {
+            info.set_estimated_cost(1_f64);
+            info.set_estimated_rows(100);
+            info.set_idx_num(1);
+        } else {
+            info.set_estimated_cost(2_147_483_647_f64);
+            info.set_estimated_rows(2_147_483_647);
+            info.set_idx_num(0);
+        }
+        Ok(())
+    }
+
+    fn open(&mut self) -> Result<ArrayTabCursor<'_>> {
+        Ok(ArrayTabCursor::new())
+    }
+}
+
+/// A cursor for the Array virtual table
+#[repr(C)]
+struct ArrayTabCursor<'vtab> {
+    /// Base class. Must be first
+    base: ffi::sqlite3_vtab_cursor,
+    /// The rowid
+    row_id: i64,
+    /// Pointer to the array of values ("pointer")
+    ptr: Option<&'vtab Vec<Value>>,
+    phantom: PhantomData<&'vtab ArrayTab>,
+}
+
+impl ArrayTabCursor<'_> {
+    fn new<'vtab>() -> ArrayTabCursor<'vtab> {
+        ArrayTabCursor {
+            base: ffi::sqlite3_vtab_cursor::default(),
+            row_id: 0,
+            ptr: None,
+            phantom: PhantomData,
+        }
+    }
+
+    fn len(&self) -> i64 {
+        match self.ptr {
+            Some(a) => a.len() as i64,
+            _ => 0,
+        }
+    }
+}
+unsafe impl VTabCursor for ArrayTabCursor<'_> {
+    fn filter(&mut self, idx_num: c_int, _idx_str: Option<&str>, args: &Filters<'_>) -> Result<()> {
+        if idx_num > 0 {
+            self.ptr = unsafe { args.get_pointer(0, ARRAY_TYPE) };
+        } else {
+            self.ptr = None;
+        }
+        self.row_id = 1;
+        Ok(())
+    }
+
+    fn next(&mut self) -> Result<()> {
+        self.row_id += 1;
+        Ok(())
+    }
+
+    fn eof(&self) -> bool {
+        self.row_id > self.len()
+    }
+
+    fn column(&self, ctx: &mut Context, i: c_int) -> Result<()> {
+        match i {
+            CARRAY_COLUMN_POINTER => Ok(()),
+            _ => {
+                if let Some(array) = self.ptr {
+                    let value = &array[(self.row_id - 1) as usize];
+                    ctx.set_result(&value)
+                } else {
+                    Ok(())
+                }
+            }
+        }
+    }
+
+    fn rowid(&self) -> Result<i64> {
+        Ok(self.row_id)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    #[cfg(all(target_family = "wasm", target_os = "unknown"))]
+    use wasm_bindgen_test::wasm_bindgen_test as test;
+
+    use crate::types::Value;
+    use crate::vtab::array;
+    use crate::{Connection, Result};
+    use std::rc::Rc;
+
+    #[test]
+    fn test_array_module() -> Result<()> {
+        let db = Connection::open_in_memory()?;
+        array::load_module(&db)?;
+
+        let v = vec![1i64, 2, 3, 4];
+        let values: Vec<Value> = v.into_iter().map(Value::from).collect();
+        let ptr = Rc::new(values);
+        {
+            let mut stmt = db.prepare("SELECT value from rarray(?1);")?;
+
+            let rows = stmt.query_map([&ptr], |row| row.get::<_, i64>(0))?;
+            assert_eq!(2, Rc::strong_count(&ptr));
+            let mut count = 0;
+            for (i, value) in rows.enumerate() {
+                assert_eq!(i as i64, value? - 1);
+                count += 1;
+            }
+            assert_eq!(4, count);
+        }
+        assert_eq!(1, Rc::strong_count(&ptr));
+        Ok(())
+    }
+}