Introduce the field-id-docid-facet-values database

src/heed_codec/facet/field_doc_id_facet_f64_codec.rs

@@ -0,0 +1,36 @@
+use std::borrow::Cow;
+use std::convert::TryInto;
+
+use crate::{FieldId, DocumentId};
+use crate::facet::value_encoding::f64_into_bytes;
+
+pub struct FieldDocIdFacetF64Codec;
+
+impl<'a> heed::BytesDecode<'a> for FieldDocIdFacetF64Codec {
+    type DItem = (FieldId, DocumentId, f64);
+
+    fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
+        let (field_id, bytes) = bytes.split_first()?;
+
+        let (document_id_bytes, bytes) = bytes.split_at(4);
+        let document_id = document_id_bytes.try_into().map(u32::from_be_bytes).ok()?;
+
+        let value = bytes[8..16].try_into().map(f64::from_be_bytes).ok()?;
+
+        Some((*field_id, document_id, value))
+    }
+}
+
+impl<'a> heed::BytesEncode<'a> for FieldDocIdFacetF64Codec {
+    type EItem = (FieldId, DocumentId, f64);
+
+    fn bytes_encode((field_id, document_id, value): &Self::EItem) -> Option<Cow<[u8]>> {
+        let mut bytes = Vec::with_capacity(1 + 4 + 8 + 8);
+        bytes.push(*field_id);
+        bytes.extend_from_slice(&document_id.to_be_bytes());
+        let value_bytes = f64_into_bytes(*value)?;
+        bytes.extend_from_slice(&value_bytes);
+        bytes.extend_from_slice(&value.to_be_bytes());
+        Some(Cow::Owned(bytes))
+    }
+}

src/heed_codec/facet/field_doc_id_facet_i64_codec.rs

@@ -0,0 +1,34 @@
+use std::borrow::Cow;
+use std::convert::TryInto;
+
+use crate::facet::value_encoding::{i64_into_bytes, i64_from_bytes};
+use crate::{FieldId, DocumentId};
+
+pub struct FieldDocIdFacetI64Codec;
+
+impl<'a> heed::BytesDecode<'a> for FieldDocIdFacetI64Codec {
+    type DItem = (FieldId, DocumentId, i64);
+
+    fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
+        let (field_id, bytes) = bytes.split_first()?;
+
+        let (document_id_bytes, bytes) = bytes.split_at(4);
+        let document_id = document_id_bytes.try_into().map(u32::from_be_bytes).ok()?;
+
+        let value = bytes[..8].try_into().map(i64_from_bytes).ok()?;
+
+        Some((*field_id, document_id, value))
+    }
+}
+
+impl<'a> heed::BytesEncode<'a> for FieldDocIdFacetI64Codec {
+    type EItem = (FieldId, DocumentId, i64);
+
+    fn bytes_encode((field_id, document_id, value): &Self::EItem) -> Option<Cow<[u8]>> {
+        let mut bytes = Vec::with_capacity(1 + 4 + 8);
+        bytes.push(*field_id);
+        bytes.extend_from_slice(&document_id.to_be_bytes());
+        bytes.extend_from_slice(&i64_into_bytes(*value));
+        Some(Cow::Owned(bytes))
+    }
+}

src/heed_codec/facet/field_doc_id_facet_string_codec.rs

@@ -0,0 +1,31 @@
+use std::borrow::Cow;
+use std::convert::TryInto;
+use std::str;
+
+use crate::{FieldId, DocumentId};
+
+pub struct FieldDocIdFacetStringCodec;
+
+impl<'a> heed::BytesDecode<'a> for FieldDocIdFacetStringCodec {
+    type DItem = (FieldId, DocumentId, &'a str);
+
+    fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
+        let (field_id, bytes) = bytes.split_first()?;
+        let (document_id_bytes, bytes) = bytes.split_at(4);
+        let document_id = document_id_bytes.try_into().map(u32::from_be_bytes).ok()?;
+        let value = str::from_utf8(bytes).ok()?;
+        Some((*field_id, document_id, value))
+    }
+}
+
+impl<'a> heed::BytesEncode<'a> for FieldDocIdFacetStringCodec {
+    type EItem = (FieldId, DocumentId, &'a str);
+
+    fn bytes_encode((field_id, document_id, value): &Self::EItem) -> Option<Cow<[u8]>> {
+        let mut bytes = Vec::with_capacity(1 + 4 + value.len());
+        bytes.push(*field_id);
+        bytes.extend_from_slice(&document_id.to_be_bytes());
+        bytes.extend_from_slice(value.as_bytes());
+        Some(Cow::Owned(bytes))
+    }
+}

src/heed_codec/facet/mod.rs

@@ -1,7 +1,13 @@
 mod facet_level_value_f64_codec;
 mod facet_level_value_i64_codec;
 mod facet_value_string_codec;
+mod field_doc_id_facet_f64_codec;
+mod field_doc_id_facet_i64_codec;
+mod field_doc_id_facet_string_codec;
 
 pub use self::facet_level_value_f64_codec::FacetLevelValueF64Codec;
 pub use self::facet_level_value_i64_codec::FacetLevelValueI64Codec;
 pub use self::facet_value_string_codec::FacetValueStringCodec;
+pub use self::field_doc_id_facet_f64_codec::FieldDocIdFacetF64Codec;
+pub use self::field_doc_id_facet_i64_codec::FieldDocIdFacetI64Codec;
+pub use self::field_doc_id_facet_string_codec::FieldDocIdFacetStringCodec;