implements filter logic

meilisearch-core/src/error.rs

@@ -33,6 +33,28 @@ impl From<io::Error> for Error {
     }
 }
 
+impl From<PestError<Rule>> for Error {
+    fn from(error: PestError<Rule>) -> Error {
+        Error::FilterParseError(error.renamed_rules(|r| {
+            let s  = match r {
+                Rule::or => "OR",
+                Rule::and => "AND",
+                Rule::not => "NOT",
+                Rule::string => "string",
+                Rule::word => "word",
+                Rule::greater => "field>value",
+                Rule::less => "field<value",
+                Rule::eq => "field:value",
+                Rule::leq => "field<=value",
+                Rule::geq => "field>=value",
+                Rule::key => "key",
+                _ => "other",
+            };
+            s.to_string()
+        }))
+    }
+} 
+
 impl From<meilisearch_schema::Error> for Error {
     fn from(error: meilisearch_schema::Error) -> Error {
         Error::Schema(error)

meilisearch-core/src/filters/condition.rs

@@ -0,0 +1,200 @@
+use std::str::FromStr;
+use std::cmp::Ordering;
+
+use crate::error::Error;
+use crate::{store::Index, DocumentId, MainT};
+use heed::RoTxn;
+use meilisearch_schema::{FieldId, Schema};
+use pest::error::{Error as PestError, ErrorVariant};
+use pest::iterators::Pair;
+use serde_json::{Value, Number};
+use super::parser::Rule;
+
+#[derive(Debug)]
+enum ConditionType {
+    Greater,
+    Less,
+    Equal,
+    LessEqual,
+    GreaterEqual,
+    NotEqual,
+}
+
+/// We need to infer type when the filter is constructed
+/// and match every possible types it can be parsed into.
+#[derive(Debug)]
+struct ConditionValue<'a> {
+    string: &'a str,
+    boolean: Option<bool>,
+    number: Option<Number>
+}
+
+impl<'a> ConditionValue<'a> {
+    pub fn new(value: &Pair<'a, Rule>) -> Self {
+        let value = match value.as_rule() {
+            Rule::string | Rule::word => {
+                let string =  value.as_str();
+                let boolean = match value.as_str() {
+                    "true" => Some(true),
+                    "false" => Some(false),
+                    _ => None,
+                };
+                let number = Number::from_str(value.as_str()).ok();
+                ConditionValue { string, boolean, number }
+            },
+            _ => unreachable!(),
+        };
+        value
+    }
+
+    pub fn as_str(&self) -> &str {
+        self.string.as_ref()
+    }
+
+    pub fn as_number(&self) -> Option<&Number> {
+        self.number.as_ref()
+    }
+
+    pub fn as_bool(&self) -> Option<bool> {
+        self.boolean
+    }
+}
+
+#[derive(Debug)]
+pub struct Condition<'a> {
+    field: FieldId,
+    condition: ConditionType,
+    value: ConditionValue<'a>
+}
+
+fn get_field_value<'a>(schema: &Schema, pair: Pair<'a, Rule>) -> Result<(FieldId, ConditionValue<'a>), Error> {
+    let mut items = pair.into_inner();
+    // lexing ensures that we at least have a key
+    let key = items.next().unwrap();
+    let field = schema
+        .id(key.as_str())
+        .ok_or::<PestError<Rule>>(PestError::new_from_span(
+                ErrorVariant::CustomError {
+                    message: format!(
+                                 "attribute `{}` not found, available attributes are: {}",
+                                 key.as_str(),
+                                 schema.names().collect::<Vec<_>>().join(", ")
+                             ),
+                },
+                key.as_span()))?;
+    let value = ConditionValue::new(&items.next().unwrap());
+    Ok((field, value))
+}
+
+// undefined behavior with big numbers
+fn compare_numbers(lhs: &Number, rhs: &Number) -> Option<Ordering> {
+    match (lhs.as_i64(), lhs.as_u64(), lhs.as_f64(),
+        rhs.as_i64(), rhs.as_u64(), rhs.as_f64()) {
+    //    i64   u64  f64  i64  u64  f64
+        (Some(lhs), _, _, Some(rhs), _, _) => lhs.partial_cmp(&rhs),
+        (_, Some(lhs), _, _, Some(rhs), _) => lhs.partial_cmp(&rhs),
+        (_, _, Some(lhs), _, _, Some(rhs)) => lhs.partial_cmp(&rhs),
+        (_, _, _, _, _, _) => None,
+    }
+}
+
+impl<'a> Condition<'a> {
+    pub fn less(
+        item: Pair<'a, Rule>,
+        schema: &'a Schema,
+    ) -> Result<Self, Error> {
+        let (field, value) = get_field_value(schema, item)?;
+        let condition = ConditionType::Less;
+        Ok(Self { field, condition, value })
+    }
+
+    pub fn greater(
+        item: Pair<'a, Rule>,
+        schema: &'a Schema,
+    ) -> Result<Self, Error> {
+        let (field, value) = get_field_value(schema, item)?;
+        let condition = ConditionType::Greater;
+        Ok(Self { field, condition, value })
+    }
+
+    pub fn neq(
+        item: Pair<'a, Rule>,
+        schema: &'a Schema,
+    ) -> Result<Self, Error> {
+        let (field, value) = get_field_value(schema, item)?;
+        let condition = ConditionType::NotEqual;
+        Ok(Self { field, condition, value })
+    }
+
+    pub fn geq(
+        item: Pair<'a, Rule>,
+        schema: &'a Schema,
+    ) -> Result<Self, Error> {
+        let (field, value) = get_field_value(schema, item)?;
+        let condition = ConditionType::GreaterEqual;
+        Ok(Self { field, condition, value })
+    }
+
+    pub fn leq(
+        item: Pair<'a, Rule>,
+        schema: &'a Schema,
+    ) -> Result<Self, Error> {
+        let (field, value) = get_field_value(schema, item)?;
+        let condition = ConditionType::LessEqual;
+        Ok(Self { field, condition, value })
+    }
+
+    pub fn eq(
+        item: Pair<'a, Rule>,
+        schema: &'a Schema,
+    ) -> Result<Self, Error> {
+        let (field, value) = get_field_value(schema, item)?;
+        let condition = ConditionType::Equal;
+        Ok(Self { field, condition, value })
+    }
+
+    pub fn test(
+        &self,
+        reader: &RoTxn<MainT>,
+        index: &Index,
+        document_id: DocumentId,
+    ) -> Result<bool, Error> {
+        match index.document_attribute::<Value>(reader, document_id, self.field)? {
+            Some(Value::String(s)) => {
+                let value = self.value.as_str();
+                match self.condition {
+                    ConditionType::Equal => Ok(unicase::eq(value, &s)),
+                    ConditionType::NotEqual => Ok(!unicase::eq(value, &s)),
+                    _ => Ok(false)
+                }
+            },
+            Some(Value::Number(n)) => { 
+                if let Some(value) = self.value.as_number() {
+                    if let Some(ord) = compare_numbers(&n, value) {
+                        let res =  match self.condition {
+                            ConditionType::Equal => ord == Ordering::Equal,
+                            ConditionType::NotEqual => ord != Ordering::Equal,
+                            ConditionType::GreaterEqual => ord != Ordering::Less,
+                            ConditionType::LessEqual => ord != Ordering::Greater,
+                            ConditionType::Greater => ord == Ordering::Greater,
+                            ConditionType::Less => ord == Ordering::Less,
+                        };
+                        return Ok(res)
+                    } 
+                } 
+                Ok(false)
+            },
+            Some(Value::Bool(b)) => {
+                if let Some(value) = self.value.as_bool() {
+                    return match self.condition {
+                        ConditionType::Equal => Ok(b == value),
+                        ConditionType::NotEqual => Ok(b != value),
+                        _ => Ok(false)
+                    }
+                }
+                Ok(false)
+            },
+            _ => Ok(false),
+        }
+    }
+}

meilisearch-core/src/filters/mod.rs

@@ -0,0 +1,125 @@
+mod parser;
+mod condition;
+
+pub(crate) use parser::Rule;
+
+use std::ops::Not;
+
+use condition::Condition;
+use crate::error::Error;
+use crate::{DocumentId, MainT, store::Index};
+use heed::RoTxn;
+use meilisearch_schema::Schema;
+use parser::{PREC_CLIMBER, FilterParser};
+use pest::iterators::{Pair, Pairs};
+use pest::Parser;
+
+type FilterResult<'a> = Result<Filter<'a>, Error>;
+
+#[derive(Debug)]
+pub enum Filter<'a> {
+    Condition(Condition<'a>),
+    Or(Box<Self>, Box<Self>),
+    And(Box<Self>, Box<Self>),
+    Not(Box<Self>),
+}
+
+impl<'a> Filter<'a> {
+    pub fn parse(expr: &'a str, schema: &'a Schema) -> FilterResult<'a> {
+        let mut lexed = FilterParser::parse(Rule::prgm, expr.as_ref())?;
+        Self::build(lexed.next().unwrap().into_inner(), schema)
+    }
+
+    pub fn test(
+        &self,
+        reader: &RoTxn<MainT>,
+        index: &Index,
+        document_id: DocumentId,
+    ) -> Result<bool, Error> {
+        use Filter::*;
+        match self {
+            Condition(c) => c.test(reader, index, document_id),
+            Or(lhs, rhs) => Ok(
+                lhs.test(reader, index, document_id)? || rhs.test(reader, index, document_id)?
+            ),
+            And(lhs, rhs) => Ok(
+                lhs.test(reader, index, document_id)? && rhs.test(reader, index, document_id)?
+            ),
+            Not(op) => op.test(reader, index, document_id).map(bool::not),
+        }
+    }
+
+    fn build(expression: Pairs<'a, Rule>, schema: &'a Schema) -> FilterResult<'a> {
+        PREC_CLIMBER.climb(
+            expression,
+            |pair: Pair<Rule>| match pair.as_rule() {
+                Rule::eq => Ok(Filter::Condition(Condition::eq(pair, schema)?)),
+                Rule::greater => Ok(Filter::Condition(Condition::greater(pair, schema)?)),
+                Rule::less => Ok(Filter::Condition(Condition::less(pair, schema)?)),
+                Rule::neq => Ok(Filter::Condition(Condition::neq(pair, schema)?)),
+                Rule::geq => Ok(Filter::Condition(Condition::geq(pair, schema)?)),
+                Rule::leq => Ok(Filter::Condition(Condition::leq(pair, schema)?)),
+                Rule::prgm => Self::build(pair.into_inner(), schema),
+                Rule::not => Ok(Filter::Not(Box::new(Self::build(
+                    pair.into_inner(),
+                    schema,
+                )?))),
+                _ => unreachable!(),
+            },
+            |lhs: FilterResult, op: Pair<Rule>, rhs: FilterResult| match op.as_rule() {
+                Rule::or => Ok(Filter::Or(Box::new(lhs?), Box::new(rhs?))),
+                Rule::and => Ok(Filter::And(Box::new(lhs?), Box::new(rhs?))),
+                _ => unreachable!(),
+            },
+        )
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn invalid_syntax() {
+        assert!(FilterParser::parse(Rule::prgm, "field : id").is_err());
+        assert!(FilterParser::parse(Rule::prgm, "field=hello hello").is_err());
+        assert!(FilterParser::parse(Rule::prgm, "field=hello OR OR").is_err());
+        assert!(FilterParser::parse(Rule::prgm, "OR field:hello").is_err());
+        assert!(FilterParser::parse(Rule::prgm, r#"field="hello world"#).is_err());
+        assert!(FilterParser::parse(Rule::prgm, r#"field='hello world"#).is_err());
+        assert!(FilterParser::parse(Rule::prgm, "NOT field=").is_err());
+        assert!(FilterParser::parse(Rule::prgm, "N").is_err());
+        assert!(FilterParser::parse(Rule::prgm, "(field=1").is_err());
+        assert!(FilterParser::parse(Rule::prgm, "(field=1))").is_err());
+        assert!(FilterParser::parse(Rule::prgm, "field=1ORfield=2").is_err());
+        assert!(FilterParser::parse(Rule::prgm, "field=1 ( OR field=2)").is_err());
+        assert!(FilterParser::parse(Rule::prgm, "hello world=1").is_err());
+        assert!(FilterParser::parse(Rule::prgm, "").is_err());
+        assert!(FilterParser::parse(Rule::prgm, r#"((((((hello=world)))))"#).is_err());
+    }
+
+    #[test]
+    fn valid_syntax() {
+        assert!(FilterParser::parse(Rule::prgm, "field = id").is_ok());
+        assert!(FilterParser::parse(Rule::prgm, "field=id").is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"field >= 10"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"field <= 10"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"field="hello world""#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"field='hello world'"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"field > 10"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"field < 10"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"field < 10 AND NOT field=5"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"field=true OR NOT field=5"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"NOT field=true OR NOT field=5"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"field='hello world' OR ( NOT field=true OR NOT field=5 )"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"field='hello \'worl\'d' OR ( NOT field=true OR NOT field=5 )"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"field="hello \"worl\"d" OR ( NOT field=true OR NOT field=5 )"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"((((((hello=world))))))"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#""foo bar" > 10"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#""foo bar" = 10"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"'foo bar' = 10"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"'foo bar' <= 10"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"'foo bar' != 10"#).is_ok());
+        assert!(FilterParser::parse(Rule::prgm, r#"bar != 10"#).is_ok());
+    }
+}