Make allocating field names avoidable for range and exists queries.

If the field names are statically known, `Cow::Borrowed(&'static str)` can
handle them without allocations. The general case is still handled by
`Cow::Owned(String)`.

src/query/exist_query.rs

@@ -1,4 +1,4 @@
-use core::fmt::Debug;
+use std::borrow::Cow;
 
 use columnar::{ColumnIndex, DynamicColumn};
 
@@ -14,7 +14,7 @@ use crate::{DocId, Score, TantivyError};
 /// All of the matched documents get the score 1.0.
 #[derive(Clone, Debug)]
 pub struct ExistsQuery {
-    field_name: String,
+    field: Cow<'static, str>,
 }
 
 impl ExistsQuery {
@@ -23,40 +23,42 @@ impl ExistsQuery {
     /// This query matches all documents with at least one non-null value in the specified field.
     /// This constructor never fails, but executing the search with this query will return an
     /// error if the specified field doesn't exists or is not a fast field.
-    pub fn new_exists_query(field: String) -> ExistsQuery {
-        ExistsQuery { field_name: field }
+    pub fn new_exists_query<F: Into<Cow<'static, str>>>(field: F) -> ExistsQuery {
+        ExistsQuery {
+            field: field.into(),
+        }
     }
 }
 
 impl Query for ExistsQuery {
     fn weight(&self, enable_scoring: EnableScoring) -> crate::Result<Box<dyn Weight>> {
         let schema = enable_scoring.schema();
-        let Some((field, _path)) = schema.find_field(&self.field_name) else {
-            return Err(TantivyError::FieldNotFound(self.field_name.clone()));
+        let Some((field, _path)) = schema.find_field(&self.field) else {
+            return Err(TantivyError::FieldNotFound(self.field.to_string()));
         };
         let field_type = schema.get_field_entry(field).field_type();
         if !field_type.is_fast() {
             return Err(TantivyError::SchemaError(format!(
                 "Field {} is not a fast field.",
-                self.field_name
+                self.field
             )));
         }
         Ok(Box::new(ExistsWeight {
-            field_name: self.field_name.clone(),
+            field: self.field.clone(),
         }))
     }
 }
 
 /// Weight associated with the `ExistsQuery` query.
 pub struct ExistsWeight {
-    field_name: String,
+    field: Cow<'static, str>,
 }
 
 impl Weight for ExistsWeight {
     fn scorer(&self, reader: &SegmentReader, boost: Score) -> crate::Result<Box<dyn Scorer>> {
         let fast_field_reader = reader.fast_fields();
         let dynamic_columns: crate::Result<Vec<DynamicColumn>> = fast_field_reader
-            .dynamic_column_handles(&self.field_name)?
+            .dynamic_column_handles(&self.field)?
             .into_iter()
             .map(|handle| handle.open().map_err(|io_error| io_error.into()))
             .collect();

src/query/range_query/range_query.rs

@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::io;
 use std::net::Ipv6Addr;
 use std::ops::{Bound, Range};
@@ -68,7 +69,7 @@ use crate::{DateTime, DocId, Score};
 /// ```
 #[derive(Clone, Debug)]
 pub struct RangeQuery {
-    field: String,
+    field: Cow<'static, str>,
     value_type: Type,
     lower_bound: Bound<Vec<u8>>,
     upper_bound: Bound<Vec<u8>>,
@@ -80,15 +81,15 @@ impl RangeQuery {
     ///
     /// If the value type is not correct, something may go terribly wrong when
     /// the `Weight` object is created.
-    pub fn new_term_bounds(
-        field: String,
+    pub fn new_term_bounds<F: Into<Cow<'static, str>>>(
+        field: F,
         value_type: Type,
         lower_bound: &Bound<Term>,
         upper_bound: &Bound<Term>,
     ) -> RangeQuery {
         let verify_and_unwrap_term = |val: &Term| val.serialized_value_bytes().to_owned();
         RangeQuery {
-            field,
+            field: field.into(),
             value_type,
             lower_bound: map_bound(lower_bound, verify_and_unwrap_term),
             upper_bound: map_bound(upper_bound, verify_and_unwrap_term),
@@ -100,7 +101,7 @@ impl RangeQuery {
     ///
     /// If the field is not of the type `i64`, tantivy
     /// will panic when the `Weight` object is created.
-    pub fn new_i64(field: String, range: Range<i64>) -> RangeQuery {
+    pub fn new_i64<F: Into<Cow<'static, str>>>(field: F, range: Range<i64>) -> RangeQuery {
         RangeQuery::new_i64_bounds(
             field,
             Bound::Included(range.start),
@@ -115,8 +116,8 @@ impl RangeQuery {
     ///
     /// If the field is not of the type `i64`, tantivy
     /// will panic when the `Weight` object is created.
-    pub fn new_i64_bounds(
-        field: String,
+    pub fn new_i64_bounds<F: Into<Cow<'static, str>>>(
+        field: F,
         lower_bound: Bound<i64>,
         upper_bound: Bound<i64>,
     ) -> RangeQuery {
@@ -126,7 +127,7 @@ impl RangeQuery {
                 .to_owned()
         };
         RangeQuery {
-            field,
+            field: field.into(),
             value_type: Type::I64,
             lower_bound: map_bound(&lower_bound, make_term_val),
             upper_bound: map_bound(&upper_bound, make_term_val),
@@ -138,7 +139,7 @@ impl RangeQuery {
     ///
     /// If the field is not of the type `f64`, tantivy
     /// will panic when the `Weight` object is created.
-    pub fn new_f64(field: String, range: Range<f64>) -> RangeQuery {
+    pub fn new_f64<F: Into<Cow<'static, str>>>(field: F, range: Range<f64>) -> RangeQuery {
         RangeQuery::new_f64_bounds(
             field,
             Bound::Included(range.start),
@@ -153,8 +154,8 @@ impl RangeQuery {
     ///
     /// If the field is not of the type `f64`, tantivy
     /// will panic when the `Weight` object is created.
-    pub fn new_f64_bounds(
-        field: String,
+    pub fn new_f64_bounds<F: Into<Cow<'static, str>>>(
+        field: F,
         lower_bound: Bound<f64>,
         upper_bound: Bound<f64>,
     ) -> RangeQuery {
@@ -164,7 +165,7 @@ impl RangeQuery {
                 .to_owned()
         };
         RangeQuery {
-            field,
+            field: field.into(),
             value_type: Type::F64,
             lower_bound: map_bound(&lower_bound, make_term_val),
             upper_bound: map_bound(&upper_bound, make_term_val),
@@ -179,8 +180,8 @@ impl RangeQuery {
     ///
     /// If the field is not of the type `u64`, tantivy
     /// will panic when the `Weight` object is created.
-    pub fn new_u64_bounds(
-        field: String,
+    pub fn new_u64_bounds<F: Into<Cow<'static, str>>>(
+        field: F,
         lower_bound: Bound<u64>,
         upper_bound: Bound<u64>,
     ) -> RangeQuery {
@@ -190,7 +191,7 @@ impl RangeQuery {
                 .to_owned()
         };
         RangeQuery {
-            field,
+            field: field.into(),
             value_type: Type::U64,
             lower_bound: map_bound(&lower_bound, make_term_val),
             upper_bound: map_bound(&upper_bound, make_term_val),
@@ -202,8 +203,8 @@ impl RangeQuery {
     ///
     /// If the field is not of the type `ip`, tantivy
     /// will panic when the `Weight` object is created.
-    pub fn new_ip_bounds(
-        field: String,
+    pub fn new_ip_bounds<F: Into<Cow<'static, str>>>(
+        field: F,
         lower_bound: Bound<Ipv6Addr>,
         upper_bound: Bound<Ipv6Addr>,
     ) -> RangeQuery {
@@ -213,7 +214,7 @@ impl RangeQuery {
                 .to_owned()
         };
         RangeQuery {
-            field,
+            field: field.into(),
             value_type: Type::IpAddr,
             lower_bound: map_bound(&lower_bound, make_term_val),
             upper_bound: map_bound(&upper_bound, make_term_val),
@@ -225,7 +226,7 @@ impl RangeQuery {
     ///
     /// If the field is not of the type `u64`, tantivy
     /// will panic when the `Weight` object is created.
-    pub fn new_u64(field: String, range: Range<u64>) -> RangeQuery {
+    pub fn new_u64<F: Into<Cow<'static, str>>>(field: F, range: Range<u64>) -> RangeQuery {
         RangeQuery::new_u64_bounds(
             field,
             Bound::Included(range.start),
@@ -240,8 +241,8 @@ impl RangeQuery {
     ///
     /// If the field is not of the type `date`, tantivy
     /// will panic when the `Weight` object is created.
-    pub fn new_date_bounds(
-        field: String,
+    pub fn new_date_bounds<F: Into<Cow<'static, str>>>(
+        field: F,
         lower_bound: Bound<DateTime>,
         upper_bound: Bound<DateTime>,
     ) -> RangeQuery {
@@ -251,7 +252,7 @@ impl RangeQuery {
                 .to_owned()
         };
         RangeQuery {
-            field,
+            field: field.into(),
             value_type: Type::Date,
             lower_bound: map_bound(&lower_bound, make_term_val),
             upper_bound: map_bound(&upper_bound, make_term_val),
@@ -263,7 +264,7 @@ impl RangeQuery {
     ///
     /// If the field is not of the type `date`, tantivy
     /// will panic when the `Weight` object is created.
-    pub fn new_date(field: String, range: Range<DateTime>) -> RangeQuery {
+    pub fn new_date<F: Into<Cow<'static, str>>>(field: F, range: Range<DateTime>) -> RangeQuery {
         RangeQuery::new_date_bounds(
             field,
             Bound::Included(range.start),
@@ -278,14 +279,14 @@ impl RangeQuery {
     ///
     /// If the field is not of the type `Str`, tantivy
     /// will panic when the `Weight` object is created.
-    pub fn new_str_bounds(
-        field: String,
+    pub fn new_str_bounds<F: Into<Cow<'static, str>>>(
+        field: F,
         lower_bound: Bound<&str>,
         upper_bound: Bound<&str>,
     ) -> RangeQuery {
         let make_term_val = |val: &&str| val.as_bytes().to_vec();
         RangeQuery {
-            field,
+            field: field.into(),
             value_type: Type::Str,
             lower_bound: map_bound(&lower_bound, make_term_val),
             upper_bound: map_bound(&upper_bound, make_term_val),
@@ -297,7 +298,7 @@ impl RangeQuery {
     ///
     /// If the field is not of the type `Str`, tantivy
     /// will panic when the `Weight` object is created.
-    pub fn new_str(field: String, range: Range<&str>) -> RangeQuery {
+    pub fn new_str<F: Into<Cow<'static, str>>>(field: F, range: Range<&str>) -> RangeQuery {
         RangeQuery::new_str_bounds(
             field,
             Bound::Included(range.start),
@@ -358,7 +359,7 @@ impl Query for RangeQuery {
                 let lower_bound = map_bound_res(&self.lower_bound, parse_ip_from_bytes)?;
                 let upper_bound = map_bound_res(&self.upper_bound, parse_ip_from_bytes)?;
                 Ok(Box::new(IPFastFieldRangeWeight::new(
-                    self.field.to_string(),
+                    self.field.clone(),
                     lower_bound,
                     upper_bound,
                 )))
@@ -373,14 +374,14 @@ impl Query for RangeQuery {
                 let lower_bound = map_bound(&self.lower_bound, parse_from_bytes);
                 let upper_bound = map_bound(&self.upper_bound, parse_from_bytes);
                 Ok(Box::new(FastFieldRangeWeight::new_u64_lenient(
-                    self.field.to_string(),
+                    self.field.clone(),
                     lower_bound,
                     upper_bound,
                 )))
             }
         } else {
             Ok(Box::new(RangeWeight {
-                field: self.field.to_string(),
+                field: self.field.clone(),
                 lower_bound: self.lower_bound.clone(),
                 upper_bound: self.upper_bound.clone(),
                 limit: self.limit,
@@ -390,7 +391,7 @@ impl Query for RangeQuery {
 }
 
 pub struct RangeWeight {
-    field: String,
+    field: Cow<'static, str>,
     lower_bound: Bound<Vec<u8>>,
     upper_bound: Bound<Vec<u8>>,
     limit: Option<u64>,

src/query/range_query/range_query_ip_fastfield.rs

@@ -2,6 +2,7 @@
 //! We use this variant only if the fastfield exists, otherwise the default in `range_query` is
 //! used, which uses the term dictionary + postings.
 
+use std::borrow::Cow;
 use std::net::Ipv6Addr;
 use std::ops::{Bound, RangeInclusive};
 
@@ -13,14 +14,18 @@ use crate::{DocId, DocSet, Score, SegmentReader, TantivyError};
 
 /// `IPFastFieldRangeWeight` uses the ip address fast field to execute range queries.
 pub struct IPFastFieldRangeWeight {
-    field: String,
+    field: Cow<'static, str>,
     lower_bound: Bound<Ipv6Addr>,
     upper_bound: Bound<Ipv6Addr>,
 }
 
 impl IPFastFieldRangeWeight {
     /// Creates a new IPFastFieldRangeWeight.
-    pub fn new(field: String, lower_bound: Bound<Ipv6Addr>, upper_bound: Bound<Ipv6Addr>) -> Self {
+    pub fn new(
+        field: Cow<'static, str>,
+        lower_bound: Bound<Ipv6Addr>,
+        upper_bound: Bound<Ipv6Addr>,
+    ) -> Self {
         Self {
             field,
             lower_bound,
@@ -171,7 +176,7 @@ pub mod tests {
         writer.commit().unwrap();
         let searcher = index.reader().unwrap().searcher();
         let range_weight = IPFastFieldRangeWeight {
-            field: "ips".to_string(),
+            field: Cow::Borrowed("ips"),
             lower_bound: Bound::Included(ip_addrs[1]),
             upper_bound: Bound::Included(ip_addrs[2]),
         };

src/query/range_query/range_query_u64_fastfield.rs

@@ -2,6 +2,7 @@
 //! We use this variant only if the fastfield exists, otherwise the default in `range_query` is
 //! used, which uses the term dictionary + postings.
 
+use std::borrow::Cow;
 use std::ops::{Bound, RangeInclusive};
 
 use columnar::{ColumnType, HasAssociatedColumnType, MonotonicallyMappableToU64};
@@ -14,7 +15,7 @@ use crate::{DocId, DocSet, Score, SegmentReader, TantivyError};
 /// `FastFieldRangeWeight` uses the fast field to execute range queries.
 #[derive(Clone, Debug)]
 pub struct FastFieldRangeWeight {
-    field: String,
+    field: Cow<'static, str>,
     lower_bound: Bound<u64>,
     upper_bound: Bound<u64>,
     column_type_opt: Option<ColumnType>,
@@ -23,7 +24,7 @@ pub struct FastFieldRangeWeight {
 impl FastFieldRangeWeight {
     /// Create a new FastFieldRangeWeight, using the u64 representation of any fast field.
     pub(crate) fn new_u64_lenient(
-        field: String,
+        field: Cow<'static, str>,
         lower_bound: Bound<u64>,
         upper_bound: Bound<u64>,
     ) -> Self {
@@ -39,7 +40,7 @@ impl FastFieldRangeWeight {
 
     /// Create a new `FastFieldRangeWeight` for a range of a u64-mappable type .
     pub fn new<T: HasAssociatedColumnType + MonotonicallyMappableToU64>(
-        field: String,
+        field: Cow<'static, str>,
         lower_bound: Bound<T>,
         upper_bound: Bound<T>,
     ) -> Self {
@@ -130,6 +131,7 @@ fn bound_to_value_range<T: MonotonicallyMappableToU64>(
 
 #[cfg(test)]
 pub mod tests {
+    use std::borrow::Cow;
     use std::ops::{Bound, RangeInclusive};
 
     use proptest::prelude::*;
@@ -214,7 +216,7 @@ pub mod tests {
         writer.commit().unwrap();
         let searcher = index.reader().unwrap().searcher();
         let range_query = FastFieldRangeWeight::new_u64_lenient(
-            "test_field".to_string(),
+            Cow::Borrowed("test_field"),
             Bound::Included(50_000),
             Bound::Included(50_002),
         );