mentat/core/src/lib.rs
Richard Newman a5023c70cb Use Rc for TypedValue, Variable, and query Ident keywords. (#395) r=nalexander
Part 1, core: use Rc for String and Keyword.
Part 2, query: use Rc for Variable.
Part 3, sql: use Rc for args in SQLiteQueryBuilder.
Part 4, query-algebrizer: use Rc.
Part 5, db: use Rc.
Part 6, query-parser: use Rc.
Part 7, query-projector: use Rc.
Part 8, query-translator: use Rc.
Part 9, top level: use Rc.
Part 10: intern Ident and IdentOrKeyword.
2017-04-02 21:38:36 -07:00

491 lines
17 KiB
Rust

// Copyright 2016 Mozilla
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
// this file except in compliance with the License. You may obtain a copy of the
// License at http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.
#[macro_use]
extern crate lazy_static;
extern crate ordered_float;
extern crate edn;
pub mod values;
use std::collections::BTreeMap;
use std::rc::Rc;
use self::ordered_float::OrderedFloat;
use self::edn::NamespacedKeyword;
/// Core types defining a Mentat knowledge base.
/// Represents one entid in the entid space.
///
/// Per https://www.sqlite.org/datatype3.html (see also http://stackoverflow.com/a/8499544), SQLite
/// stores signed integers up to 64 bits in size. Since u32 is not appropriate for our use case, we
/// use i64 rather than manually truncating u64 to u63 and casting to i64 throughout the codebase.
pub type Entid = i64;
/// The attribute of each Mentat assertion has a :db/valueType constraining the value to a
/// particular set. Mentat recognizes the following :db/valueType values.
#[derive(Clone,Copy,Debug,Eq,Hash,Ord,PartialOrd,PartialEq)]
pub enum ValueType {
Ref,
Boolean,
Instant,
Long,
Double,
String,
Keyword,
}
impl ValueType {
pub fn to_edn_value(&self) -> edn::Value {
match self {
&ValueType::Ref => values::DB_TYPE_REF.clone(),
&ValueType::Boolean => values::DB_TYPE_BOOLEAN.clone(),
&ValueType::Instant => values::DB_TYPE_INSTANT.clone(),
&ValueType::Long => values::DB_TYPE_LONG.clone(),
&ValueType::Double => values::DB_TYPE_DOUBLE.clone(),
&ValueType::String => values::DB_TYPE_STRING.clone(),
&ValueType::Keyword => values::DB_TYPE_KEYWORD.clone(),
}
}
}
/// Represents a Mentat value in a particular value set.
// TODO: expand to include :db.type/{instant,url,uuid}.
// TODO: BigInt?
#[derive(Clone,Debug,Eq,Hash,Ord,PartialOrd,PartialEq)]
pub enum TypedValue {
Ref(Entid),
Boolean(bool),
Long(i64),
Double(OrderedFloat<f64>),
// TODO: &str throughout?
String(Rc<String>),
Keyword(Rc<NamespacedKeyword>),
}
impl TypedValue {
/// Returns true if the provided type is `Some` and matches this value's type, or if the
/// provided type is `None`.
#[inline]
pub fn is_congruent_with<T: Into<Option<ValueType>>>(&self, t: T) -> bool {
t.into().map_or(true, |x| self.matches_type(x))
}
#[inline]
pub fn matches_type(&self, t: ValueType) -> bool {
self.value_type() == t
}
pub fn value_type(&self) -> ValueType {
match self {
&TypedValue::Ref(_) => ValueType::Ref,
&TypedValue::Boolean(_) => ValueType::Boolean,
&TypedValue::Long(_) => ValueType::Long,
&TypedValue::Double(_) => ValueType::Double,
&TypedValue::String(_) => ValueType::String,
&TypedValue::Keyword(_) => ValueType::Keyword,
}
}
/// Construct a new `TypedValue::Keyword` instance by cloning the provided
/// values and wrapping them in a new `Rc`. This is expensive, so this might
/// be best limited to tests.
pub fn typed_ns_keyword(ns: &str, name: &str) -> TypedValue {
TypedValue::Keyword(Rc::new(NamespacedKeyword::new(ns, name)))
}
/// Construct a new `TypedValue::String` instance by cloning the provided
/// value and wrapping it in a new `Rc`. This is expensive, so this might
/// be best limited to tests.
pub fn typed_string(s: &str) -> TypedValue {
TypedValue::String(Rc::new(s.to_string()))
}
}
// Put this here rather than in `db` simply because it's widely needed.
pub trait SQLValueType {
fn value_type_tag(&self) -> i32;
fn accommodates_integer(&self, int: i64) -> bool;
}
impl SQLValueType for ValueType {
fn value_type_tag(&self) -> i32 {
match *self {
ValueType::Ref => 0,
ValueType::Boolean => 1,
ValueType::Instant => 4,
// SQLite distinguishes integral from decimal types, allowing long and double to share a tag.
ValueType::Long => 5,
ValueType::Double => 5,
ValueType::String => 10,
ValueType::Keyword => 13,
}
}
/// Returns true if the provided integer is in the SQLite value space of this type. For
/// example, `1` is how we encode `true`.
///
/// ```
/// use mentat_core::{ValueType, SQLValueType};
/// assert!(ValueType::Boolean.accommodates_integer(1));
/// assert!(!ValueType::Boolean.accommodates_integer(-1));
/// assert!(!ValueType::Boolean.accommodates_integer(10));
/// assert!(!ValueType::String.accommodates_integer(10));
/// ```
fn accommodates_integer(&self, int: i64) -> bool {
use ValueType::*;
match *self {
Instant | Long | Double => true,
Ref => int >= 0,
Boolean => (int == 0) || (int == 1),
ValueType::String => false,
Keyword => false,
}
}
}
#[test]
fn test_typed_value() {
assert!(TypedValue::Boolean(false).is_congruent_with(None));
assert!(TypedValue::Boolean(false).is_congruent_with(ValueType::Boolean));
assert!(!TypedValue::typed_string("foo").is_congruent_with(ValueType::Boolean));
assert!(TypedValue::typed_string("foo").is_congruent_with(ValueType::String));
assert!(TypedValue::typed_string("foo").is_congruent_with(None));
}
/// Bit flags used in `flags0` column in temporary tables created during search,
/// such as the `search_results`, `inexact_searches` and `exact_searches` tables.
/// When moving to a more concrete table, such as `datoms`, they are expanded out
/// via these flags and put into their own column rather than a bit field.
pub enum AttributeBitFlags {
IndexAVET = 1 << 0,
IndexVAET = 1 << 1,
IndexFulltext = 1 << 2,
UniqueValue = 1 << 3,
}
pub mod attribute {
#[derive(Clone,Debug,Eq,Hash,Ord,PartialOrd,PartialEq)]
pub enum Unique {
Value,
Identity,
}
}
/// A Mentat schema attribute has a value type and several other flags determining how assertions
/// with the attribute are interpreted.
///
/// TODO: consider packing this into a bitfield or similar.
#[derive(Clone,Debug,Eq,Hash,Ord,PartialOrd,PartialEq)]
pub struct Attribute {
/// The associated value type, i.e., `:db/valueType`?
pub value_type: ValueType,
/// `true` if this attribute is multi-valued, i.e., it is `:db/cardinality
/// :db.cardinality/many`. `false` if this attribute is single-valued (the default), i.e., it
/// is `:db/cardinality :db.cardinality/one`.
pub multival: bool,
/// `None` if this attribute is neither unique-value nor unique-identity.
///
/// `Some(attribute::Unique::Value)` if this attribute is unique-value, i.e., it is `:db/unique
/// :db.unique/value`.
///
/// *Unique-value* means that there is at most one assertion with the attribute and a
/// particular value in the datom store. Unique-value attributes can be used in lookup-refs.
///
/// `Some(attribute::Unique::Identity)` if this attribute is unique-identity, i.e., it is `:db/unique
/// :db.unique/identity`.
///
/// Unique-identity attributes always have value type `Ref`.
///
/// *Unique-identity* means that the attribute is *unique-value* and that they can be used in
/// lookup-refs and will automatically upsert where appropriate.
pub unique: Option<attribute::Unique>,
/// `true` if this attribute is automatically indexed, i.e., it is `:db/indexing true`.
pub index: bool,
/// `true` if this attribute is automatically fulltext indexed, i.e., it is `:db/fulltext true`.
///
/// Fulltext attributes always have string values.
pub fulltext: bool,
/// `true` if this attribute is a component, i.e., it is `:db/isComponent true`.
///
/// Component attributes always have value type `Ref`.
///
/// They are used to compose entities from component sub-entities: they are fetched recursively
/// by pull expressions, and they are automatically recursively deleted where appropriate.
pub component: bool,
}
impl Attribute {
/// Combine several attribute flags into a bitfield used in temporary search tables.
pub fn flags(&self) -> u8 {
let mut flags: u8 = 0;
if self.index {
flags |= AttributeBitFlags::IndexAVET as u8;
}
if self.value_type == ValueType::Ref {
flags |= AttributeBitFlags::IndexVAET as u8;
}
if self.fulltext {
flags |= AttributeBitFlags::IndexFulltext as u8;
}
if self.unique.is_some() {
flags |= AttributeBitFlags::UniqueValue as u8;
}
flags
}
pub fn to_edn_value(&self, ident: Option<NamespacedKeyword>) -> edn::Value {
let mut attribute_map: BTreeMap<edn::Value, edn::Value> = BTreeMap::default();
if let Some(ident) = ident {
attribute_map.insert(values::DB_IDENT.clone(), edn::Value::NamespacedKeyword(ident));
}
attribute_map.insert(values::DB_VALUE_TYPE.clone(), self.value_type.to_edn_value());
attribute_map.insert(values::DB_CARDINALITY.clone(), if self.multival { values::DB_CARDINALITY_MANY.clone() } else { values::DB_CARDINALITY_ONE.clone() });
match self.unique {
Some(attribute::Unique::Value) => { attribute_map.insert(values::DB_UNIQUE.clone(), values::DB_UNIQUE_VALUE.clone()); },
Some(attribute::Unique::Identity) => { attribute_map.insert(values::DB_UNIQUE.clone(), values::DB_UNIQUE_IDENTITY.clone()); },
None => (),
}
if self.index {
attribute_map.insert(values::DB_INDEX.clone(), edn::Value::Boolean(true));
}
if self.fulltext {
attribute_map.insert(values::DB_FULLTEXT.clone(), edn::Value::Boolean(true));
}
if self.component {
attribute_map.insert(values::DB_IS_COMPONENT.clone(), edn::Value::Boolean(true));
}
edn::Value::Map(attribute_map)
}
}
impl Default for Attribute {
fn default() -> Attribute {
Attribute {
// There's no particular reason to favour one value type, so Ref it is.
value_type: ValueType::Ref,
fulltext: false,
index: false,
multival: false,
unique: None,
component: false,
}
}
}
/// Map `NamespacedKeyword` idents (`:db/ident`) to positive integer entids (`1`).
pub type IdentMap = BTreeMap<NamespacedKeyword, Entid>;
/// Map positive integer entids (`1`) to `NamespacedKeyword` idents (`:db/ident`).
pub type EntidMap = BTreeMap<Entid, NamespacedKeyword>;
/// Map attribute entids to `Attribute` instances.
pub type SchemaMap = BTreeMap<Entid, Attribute>;
/// Represents a Mentat schema.
///
/// Maintains the mapping between string idents and positive integer entids; and exposes the schema
/// flags associated to a given entid (equivalently, ident).
///
/// TODO: consider a single bi-directional map instead of separate ident->entid and entid->ident
/// maps.
#[derive(Clone, Debug, Default, Eq, Hash, Ord, PartialOrd, PartialEq)]
pub struct Schema {
/// Map entid->ident.
///
/// Invariant: is the inverse map of `ident_map`.
pub entid_map: EntidMap,
/// Map ident->entid.
///
/// Invariant: is the inverse map of `entid_map`.
pub ident_map: IdentMap,
/// Map entid->attribute flags.
///
/// Invariant: key-set is the same as the key-set of `entid_map` (equivalently, the value-set of
/// `ident_map`).
pub schema_map: SchemaMap,
}
impl Schema {
pub fn get_ident(&self, x: Entid) -> Option<&NamespacedKeyword> {
self.entid_map.get(&x)
}
pub fn get_entid(&self, x: &NamespacedKeyword) -> Option<Entid> {
self.ident_map.get(x).map(|x| *x)
}
pub fn attribute_for_entid(&self, x: Entid) -> Option<&Attribute> {
self.schema_map.get(&x)
}
pub fn attribute_for_ident(&self, ident: &NamespacedKeyword) -> Option<&Attribute> {
self.get_entid(&ident)
.and_then(|x| self.attribute_for_entid(x))
}
/// Return true if the provided entid identifies an attribute in this schema.
pub fn is_attribute(&self, x: Entid) -> bool {
self.schema_map.contains_key(&x)
}
/// Return true if the provided ident identifies an attribute in this schema.
pub fn identifies_attribute(&self, x: &NamespacedKeyword) -> bool {
self.get_entid(x).map(|e| self.is_attribute(e)).unwrap_or(false)
}
/// Returns an symbolic representation of the schema suitable for applying across Mentat stores.
pub fn to_edn_value(&self) -> edn::Value {
edn::Value::Vector((&self.schema_map).iter()
.map(|(entid, attribute)|
attribute.to_edn_value(self.get_ident(*entid).cloned()))
.collect())
}
}
#[cfg(test)]
mod test {
use super::*;
fn associate_ident(schema: &mut Schema, i: NamespacedKeyword, e: Entid) {
schema.entid_map.insert(e, i.clone());
schema.ident_map.insert(i, e);
}
fn add_attribute(schema: &mut Schema, e: Entid, a: Attribute) {
schema.schema_map.insert(e, a);
}
#[test]
fn test_attribute_flags() {
let attr1 = Attribute {
index: true,
value_type: ValueType::Ref,
fulltext: false,
unique: None,
multival: false,
component: false,
};
assert!(attr1.flags() & AttributeBitFlags::IndexAVET as u8 != 0);
assert!(attr1.flags() & AttributeBitFlags::IndexVAET as u8 != 0);
assert!(attr1.flags() & AttributeBitFlags::IndexFulltext as u8 == 0);
assert!(attr1.flags() & AttributeBitFlags::UniqueValue as u8 == 0);
let attr2 = Attribute {
index: false,
value_type: ValueType::Boolean,
fulltext: true,
unique: Some(attribute::Unique::Value),
multival: false,
component: false,
};
assert!(attr2.flags() & AttributeBitFlags::IndexAVET as u8 == 0);
assert!(attr2.flags() & AttributeBitFlags::IndexVAET as u8 == 0);
assert!(attr2.flags() & AttributeBitFlags::IndexFulltext as u8 != 0);
assert!(attr2.flags() & AttributeBitFlags::UniqueValue as u8 != 0);
let attr3 = Attribute {
index: false,
value_type: ValueType::Boolean,
fulltext: true,
unique: Some(attribute::Unique::Identity),
multival: false,
component: false,
};
assert!(attr3.flags() & AttributeBitFlags::IndexAVET as u8 == 0);
assert!(attr3.flags() & AttributeBitFlags::IndexVAET as u8 == 0);
assert!(attr3.flags() & AttributeBitFlags::IndexFulltext as u8 != 0);
assert!(attr3.flags() & AttributeBitFlags::UniqueValue as u8 != 0);
}
#[test]
fn test_as_edn_value() {
let mut schema = Schema::default();
let attr1 = Attribute {
index: true,
value_type: ValueType::Ref,
fulltext: false,
unique: None,
multival: false,
component: false,
};
associate_ident(&mut schema, NamespacedKeyword::new("foo", "bar"), 97);
add_attribute(&mut schema, 97, attr1);
let attr2 = Attribute {
index: false,
value_type: ValueType::String,
fulltext: true,
unique: Some(attribute::Unique::Value),
multival: true,
component: false,
};
associate_ident(&mut schema, NamespacedKeyword::new("foo", "bas"), 98);
add_attribute(&mut schema, 98, attr2);
let attr3 = Attribute {
index: false,
value_type: ValueType::Boolean,
fulltext: false,
unique: Some(attribute::Unique::Identity),
multival: false,
component: true,
};
associate_ident(&mut schema, NamespacedKeyword::new("foo", "bat"), 99);
add_attribute(&mut schema, 99, attr3);
let value = schema.to_edn_value();
let expected_output = r#"[ { :db/ident :foo/bar
:db/valueType :db.type/ref
:db/cardinality :db.cardinality/one
:db/index true },
{ :db/ident :foo/bas
:db/valueType :db.type/string
:db/cardinality :db.cardinality/many
:db/unique :db.unique/value
:db/fulltext true },
{ :db/ident :foo/bat
:db/valueType :db.type/boolean
:db/cardinality :db.cardinality/one
:db/unique :db.unique/identity
:db/component true }, ]"#;
let expected_value = edn::parse::value(&expected_output).expect("to be able to parse").without_spans();
assert_eq!(expected_value, value);
// let's compare the whole thing again, just to make sure we are not changing anything when we convert to edn.
let value2 = schema.to_edn_value();
assert_eq!(expected_value, value2);
}
}
pub mod intern_set;
pub mod util;