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https://github.com/fluencelabs/llamadb
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Move ExecuteQueryPlan to queryplan module
This commit is contained in:
Dan Spencer
parent
5b921a24ba
commit
0372b5d3fe
@ -1,150 +1,8 @@
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use databaseinfo::{DatabaseInfo, ColumnValueOps};
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use queryplan::SExpression;
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// pub enum Bound<'a> {
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// Included(&'a [u8]),
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// Excluded(&'a [u8]),
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// Unbounded
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// }
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//
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// #[derive(PartialEq)]
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// pub enum Order {
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// Ascending,
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// Descending
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// }
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use databaseinfo::DatabaseInfo;
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pub trait DatabaseStorage {
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type Info: DatabaseInfo;
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type RowIterator: Iterator<Item=Box<[<Self::Info as DatabaseInfo>::ColumnValue]>>;
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type ScanTableRowIterator: Iterator<Item=Box<[<Self::Info as DatabaseInfo>::ColumnValue]>>;
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fn scan_table(&self, table: &<Self::Info as DatabaseInfo>::Table) -> Self::RowIterator;
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}
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struct Source<'a, ColumnValue: Sized + 'static> {
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parent: Option<&'a Source<'a, ColumnValue>>,
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source_id: u32,
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row: &'a [ColumnValue],
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}
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impl<'a, ColumnValue: Sized> Source<'a, ColumnValue> {
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fn find_row_from_source_id(&self, source_id: u32) -> Option<&[ColumnValue]> {
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if self.source_id == source_id {
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Some(self.row)
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} else if let Some(parent) = self.parent {
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parent.find_row_from_source_id(source_id)
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} else {
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None
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}
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}
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}
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/// The query plan is currently defined as a recursive language.
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/// Because of this, it would take some work (and foresight) to make query plan
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/// execution co-operate with the concept of iterators.
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/// For now, callbacks are used to yield rows.
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///
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/// TODO: translate query plan into procedural language
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/// (such as VM instructions, like those found in SQLite's VBDE).
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struct ExecuteQueryPlan<'s, Storage: DatabaseStorage + 's> {
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storage: &'s Storage
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}
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impl<'a, 's, Storage: DatabaseStorage> ExecuteQueryPlan<'s, Storage>
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where <Storage::Info as DatabaseInfo>::Table: 'a
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{
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pub fn new(storage: &'s Storage) -> ExecuteQueryPlan<'s, Storage> {
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ExecuteQueryPlan {
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storage: storage
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}
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}
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pub fn execute_query_plan<'b, R>(&self, expr: &SExpression<'a, Storage::Info>, result_cb: R)
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-> Result<(), ()>
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where R: Fn(&[<Storage::Info as DatabaseInfo>::ColumnValue]) -> Result<(), ()>
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{
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self.execute(expr, &result_cb, None)
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}
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fn execute<'b, 'c, R>(&self, expr: &SExpression<'a, Storage::Info>, result_cb: &'c R,
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source: Option<&Source<'b, <Storage::Info as DatabaseInfo>::ColumnValue>>)
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-> Result<(), ()>
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where R: Fn(&[<Storage::Info as DatabaseInfo>::ColumnValue]) -> Result<(), ()>
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{
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match expr {
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&SExpression::Scan { table, source_id, ref yield_fn } => {
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for row in self.storage.scan_table(table) {
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let new_source = Source {
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parent: source,
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source_id: source_id,
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row: &row
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};
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try!(self.execute(yield_fn, result_cb, Some(&new_source)));
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}
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Ok(())
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},
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&SExpression::Map { source_id, ref yield_in_fn, ref yield_out_fn } => {
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self.execute(yield_in_fn, &|row| {
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let new_source = Source {
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parent: source,
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source_id: source_id,
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row: row
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};
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self.execute(yield_out_fn, result_cb, Some(&new_source))
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}, source)
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},
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&SExpression::Yield { ref fields } => {
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let columns: Result<Vec<_>, ()>;
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columns = fields.iter().map(|e| self.resolve_value(e, source)).collect();
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match columns {
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Ok(columns) => result_cb(&columns),
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Err(()) => Err(())
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}
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},
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&SExpression::If { ref predicate, ref yield_fn } => {
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let pred_result = try!(self.resolve_value(predicate, source));
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if pred_result.tests_true() {
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self.execute(yield_fn, result_cb, source)
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} else {
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Ok(())
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}
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},
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&SExpression::ColumnField { .. } |
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&SExpression::BinaryOp { .. } |
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&SExpression::Value(..) => {
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// these expressions cannot contain yieldable rows.
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Err(())
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}
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}
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}
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fn resolve_value<'b>(&self, expr: &SExpression<'a, Storage::Info>,
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source: Option<&Source<'b, <Storage::Info as DatabaseInfo>::ColumnValue>>)
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-> Result<<Storage::Info as DatabaseInfo>::ColumnValue, ()>
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{
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match expr {
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&SExpression::Value(ref v) => Ok(v.clone()),
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&SExpression::ColumnField { source_id, column_offset } => {
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let row = source.and_then(|s| s.find_row_from_source_id(source_id));
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match row {
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Some(row) => Ok(row[column_offset as usize].clone()),
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None => Err(())
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}
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},
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&SExpression::BinaryOp { op, ref lhs, ref rhs } => {
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let l = try!(self.resolve_value(lhs, source));
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let r = try!(self.resolve_value(rhs, source));
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Ok(match op {
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// Equal => l.equal(&r),
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// NotEqual => l.not_equal(&r),
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_ => unimplemented!()
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})
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},
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_ => Err(())
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}
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}
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fn scan_table(&self, table: &<Self::Info as DatabaseInfo>::Table) -> Self::ScanTableRowIterator;
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}
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132
src/queryplan/execute.rs
Normal file
132
src/queryplan/execute.rs
Normal file
@ -0,0 +1,132 @@
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use databaseinfo::{DatabaseInfo, ColumnValueOps};
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use databasestorage::DatabaseStorage;
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use super::sexpression::SExpression;
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struct Source<'a, ColumnValue: Sized + 'static> {
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parent: Option<&'a Source<'a, ColumnValue>>,
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source_id: u32,
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row: &'a [ColumnValue],
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}
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impl<'a, ColumnValue: Sized> Source<'a, ColumnValue> {
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fn find_row_from_source_id(&self, source_id: u32) -> Option<&[ColumnValue]> {
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if self.source_id == source_id {
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Some(self.row)
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} else if let Some(parent) = self.parent {
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parent.find_row_from_source_id(source_id)
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} else {
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None
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}
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}
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}
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/// The query plan is currently defined as a recursive language.
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/// Because of this, it would take some work (and foresight) to make query plan
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/// execution co-operate with the concept of iterators.
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/// For now, callbacks are used to yield rows.
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///
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/// TODO: translate query plan into procedural language
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/// (such as VM instructions, like those found in SQLite's VBDE).
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pub struct ExecuteQueryPlan<'s, Storage: DatabaseStorage + 's> {
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storage: &'s Storage
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}
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impl<'a, 's, Storage: DatabaseStorage> ExecuteQueryPlan<'s, Storage>
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where <Storage::Info as DatabaseInfo>::Table: 'a
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{
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pub fn new(storage: &'s Storage) -> ExecuteQueryPlan<'s, Storage> {
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ExecuteQueryPlan {
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storage: storage
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}
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}
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pub fn execute_query_plan<'b, R>(&self, expr: &SExpression<'a, Storage::Info>, result_cb: R)
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-> Result<(), ()>
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where R: Fn(&[<Storage::Info as DatabaseInfo>::ColumnValue]) -> Result<(), ()>
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{
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self.execute(expr, &result_cb, None)
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}
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fn execute<'b, 'c, R>(&self, expr: &SExpression<'a, Storage::Info>, result_cb: &'c R,
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source: Option<&Source<'b, <Storage::Info as DatabaseInfo>::ColumnValue>>)
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-> Result<(), ()>
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where R: Fn(&[<Storage::Info as DatabaseInfo>::ColumnValue]) -> Result<(), ()>
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{
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match expr {
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&SExpression::Scan { table, source_id, ref yield_fn } => {
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for row in self.storage.scan_table(table) {
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let new_source = Source {
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parent: source,
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source_id: source_id,
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row: &row
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};
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try!(self.execute(yield_fn, result_cb, Some(&new_source)));
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}
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Ok(())
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},
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&SExpression::Map { source_id, ref yield_in_fn, ref yield_out_fn } => {
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self.execute(yield_in_fn, &|row| {
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let new_source = Source {
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parent: source,
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source_id: source_id,
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row: row
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};
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self.execute(yield_out_fn, result_cb, Some(&new_source))
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}, source)
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},
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&SExpression::Yield { ref fields } => {
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let columns: Result<Vec<_>, ()>;
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columns = fields.iter().map(|e| self.resolve_value(e, source)).collect();
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match columns {
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Ok(columns) => result_cb(&columns),
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Err(()) => Err(())
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}
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},
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&SExpression::If { ref predicate, ref yield_fn } => {
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let pred_result = try!(self.resolve_value(predicate, source));
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if pred_result.tests_true() {
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self.execute(yield_fn, result_cb, source)
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} else {
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Ok(())
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}
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},
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&SExpression::ColumnField { .. } |
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&SExpression::BinaryOp { .. } |
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&SExpression::Value(..) => {
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// these expressions cannot contain yieldable rows.
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Err(())
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}
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}
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}
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fn resolve_value<'b>(&self, expr: &SExpression<'a, Storage::Info>,
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source: Option<&Source<'b, <Storage::Info as DatabaseInfo>::ColumnValue>>)
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-> Result<<Storage::Info as DatabaseInfo>::ColumnValue, ()>
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{
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match expr {
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&SExpression::Value(ref v) => Ok(v.clone()),
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&SExpression::ColumnField { source_id, column_offset } => {
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let row = source.and_then(|s| s.find_row_from_source_id(source_id));
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match row {
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Some(row) => Ok(row[column_offset as usize].clone()),
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None => Err(())
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}
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},
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&SExpression::BinaryOp { op, ref lhs, ref rhs } => {
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let l = try!(self.resolve_value(lhs, source));
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let r = try!(self.resolve_value(rhs, source));
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Ok(match op {
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// Equal => l.equal(&r),
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// NotEqual => l.not_equal(&r),
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_ => unimplemented!()
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})
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},
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_ => Err(())
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}
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}
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}
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@ -5,9 +5,11 @@ use sqlsyntax::ast;
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use std::fmt;
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mod columnnames;
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mod execute;
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mod sexpression;
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mod source;
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pub use self::columnnames::*;
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pub use self::execute::*;
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pub use self::sexpression::*;
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use self::source::*;
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